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dart / sdk.git / 261f8199afca747d4e89c1dc0b2348cff81e734d / . / runtime / vm / regexp / regexp.cc
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// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/regexp/regexp.h"
#include <memory>
#include "platform/splay-tree-inl.h"
#include "platform/unicode.h"
#include "unicode/uniset.h"
#include "vm/dart_entry.h"
#include "vm/regexp/regexp_assembler.h"
#include "vm/regexp/regexp_assembler_bytecode.h"
#include "vm/regexp/regexp_ast.h"
#include "vm/regexp/unibrow-inl.h"
#include "vm/symbols.h"
#include "vm/thread.h"
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/regexp/regexp_assembler_ir.h"
#endif // !defined(DART_PRECOMPILED_RUNTIME)
#define Z (zone())
namespace dart {
// Default to generating optimized regexp code.
static constexpr bool kRegexpOptimization = true;
// More makes code generation slower, less makes V8 benchmark score lower.
static constexpr intptr_t kMaxLookaheadForBoyerMoore = 8;
ContainedInLattice AddRange(ContainedInLattice containment,
const int32_t* ranges,
intptr_t ranges_length,
Interval new_range) {
ASSERT((ranges_length & 1) == 1);
ASSERT(ranges[ranges_length - 1] == Utf::kMaxCodePoint + 1);
if (containment == kLatticeUnknown) return containment;
bool inside = false;
int32_t last = 0;
for (intptr_t i = 0; i < ranges_length;
inside = !inside, last = ranges[i], i++) {
// Consider the range from last to ranges[i].
// We haven't got to the new range yet.
if (ranges[i] <= new_range.from()) continue;
// New range is wholly inside last-ranges[i]. Note that new_range.to() is
// inclusive, but the values in ranges are not.
if (last <= new_range.from() && new_range.to() < ranges[i]) {
return Combine(containment, inside ? kLatticeIn : kLatticeOut);
}
return kLatticeUnknown;
}
return containment;
}
// -------------------------------------------------------------------
// Implementation of the Irregexp regular expression engine.
//
// The Irregexp regular expression engine is intended to be a complete
// implementation of ECMAScript regular expressions. It generates
// IR code that is subsequently compiled to native code.
// The Irregexp regexp engine is structured in three steps.
// 1) The parser generates an abstract syntax tree. See regexp_ast.cc.
// 2) From the AST a node network is created. The nodes are all
// subclasses of RegExpNode. The nodes represent states when
// executing a regular expression. Several optimizations are
// performed on the node network.
// 3) From the nodes we generate IR instructions that can actually
// execute the regular expression (perform the search). The
// code generation step is described in more detail below.
// Code generation.
//
// The nodes are divided into four main categories.
// * Choice nodes
// These represent places where the regular expression can
// match in more than one way. For example on entry to an
// alternation (foo|bar) or a repetition (*, +, ? or {}).
// * Action nodes
// These represent places where some action should be
// performed. Examples include recording the current position
// in the input string to a register (in order to implement
// captures) or other actions on register for example in order
// to implement the counters needed for {} repetitions.
// * Matching nodes
// These attempt to match some element part of the input string.
// Examples of elements include character classes, plain strings
// or back references.
// * End nodes
// These are used to implement the actions required on finding
// a successful match or failing to find a match.
//
// The code generated maintains some state as it runs. This consists of the
// following elements:
//
// * The capture registers. Used for string captures.
// * Other registers. Used for counters etc.
// * The current position.
// * The stack of backtracking information. Used when a matching node
// fails to find a match and needs to try an alternative.
//
// Conceptual regular expression execution model:
//
// There is a simple conceptual model of regular expression execution
// which will be presented first. The actual code generated is a more
// efficient simulation of the simple conceptual model:
//
// * Choice nodes are implemented as follows:
// For each choice except the last {
// push current position
// push backtrack code location
// <generate code to test for choice>
// backtrack code location:
// pop current position
// }
// <generate code to test for last choice>
//
// * Actions nodes are generated as follows
// <push affected registers on backtrack stack>
// <generate code to perform action>
// push backtrack code location
// <generate code to test for following nodes>
// backtrack code location:
// <pop affected registers to restore their state>
// <pop backtrack location from stack and go to it>
//
// * Matching nodes are generated as follows:
// if input string matches at current position
// update current position
// <generate code to test for following nodes>
// else
// <pop backtrack location from stack and go to it>
//
// Thus it can be seen that the current position is saved and restored
// by the choice nodes, whereas the registers are saved and restored by
// by the action nodes that manipulate them.
//
// The other interesting aspect of this model is that nodes are generated
// at the point where they are needed by a recursive call to Emit(). If
// the node has already been code generated then the Emit() call will
// generate a jump to the previously generated code instead. In order to
// limit recursion it is possible for the Emit() function to put the node
// on a work list for later generation and instead generate a jump. The
// destination of the jump is resolved later when the code is generated.
//
// Actual regular expression code generation.
//
// Code generation is actually more complicated than the above. In order
// to improve the efficiency of the generated code some optimizations are
// performed
//
// * Choice nodes have 1-character lookahead.
// A choice node looks at the following character and eliminates some of
// the choices immediately based on that character. This is not yet
// implemented.
// * Simple greedy loops store reduced backtracking information.
// A quantifier like /.*foo/m will greedily match the whole input. It will
// then need to backtrack to a point where it can match "foo". The naive
// implementation of this would push each character position onto the
// backtracking stack, then pop them off one by one. This would use space
// proportional to the length of the input string. However since the "."
// can only match in one way and always has a constant length (in this case
// of 1) it suffices to store the current position on the top of the stack
// once. Matching now becomes merely incrementing the current position and
// backtracking becomes decrementing the current position and checking the
// result against the stored current position. This is faster and saves
// space.
// * The current state is virtualized.
// This is used to defer expensive operations until it is clear that they
// are needed and to generate code for a node more than once, allowing
// specialized an efficient versions of the code to be created. This is
// explained in the section below.
//
// Execution state virtualization.
//
// Instead of emitting code, nodes that manipulate the state can record their
// manipulation in an object called the Trace. The Trace object can record a
// current position offset, an optional backtrack code location on the top of
// the virtualized backtrack stack and some register changes. When a node is
// to be emitted it can flush the Trace or update it. Flushing the Trace
// will emit code to bring the actual state into line with the virtual state.
// Avoiding flushing the state can postpone some work (e.g. updates of capture
// registers). Postponing work can save time when executing the regular
// expression since it may be found that the work never has to be done as a
// failure to match can occur. In addition it is much faster to jump to a
// known backtrack code location than it is to pop an unknown backtrack
// location from the stack and jump there.
//
// The virtual state found in the Trace affects code generation. For example
// the virtual state contains the difference between the actual current
// position and the virtual current position, and matching code needs to use
// this offset to attempt a match in the correct location of the input
// string. Therefore code generated for a non-trivial trace is specialized
// to that trace. The code generator therefore has the ability to generate
// code for each node several times. In order to limit the size of the
// generated code there is an arbitrary limit on how many specialized sets of
// code may be generated for a given node. If the limit is reached, the
// trace is flushed and a generic version of the code for a node is emitted.
// This is subsequently used for that node. The code emitted for non-generic
// trace is not recorded in the node and so it cannot currently be reused in
// the event that code generation is requested for an identical trace.
void RegExpTree::AppendToText(RegExpText* text) {
UNREACHABLE();
}
void RegExpAtom::AppendToText(RegExpText* text) {
text->AddElement(TextElement::Atom(this));
}
void RegExpCharacterClass::AppendToText(RegExpText* text) {
text->AddElement(TextElement::CharClass(this));
}
void RegExpText::AppendToText(RegExpText* text) {
for (intptr_t i = 0; i < elements()->length(); i++)
text->AddElement((*elements())[i]);
}
TextElement TextElement::Atom(RegExpAtom* atom) {
return TextElement(ATOM, atom);
}
TextElement TextElement::CharClass(RegExpCharacterClass* char_class) {
return TextElement(CHAR_CLASS, char_class);
}
intptr_t TextElement::length() const {
switch (text_type()) {
case ATOM:
return atom()->length();
case CHAR_CLASS:
return 1;
}
UNREACHABLE();
return 0;
}
class FrequencyCollator : public ValueObject {
public:
FrequencyCollator() : total_samples_(0) {
for (intptr_t i = 0; i < RegExpMacroAssembler::kTableSize; i++) {
frequencies_[i] = CharacterFrequency(i);
}
}
void CountCharacter(intptr_t character) {
intptr_t index = (character & RegExpMacroAssembler::kTableMask);
frequencies_[index].Increment();
total_samples_++;
}
// Does not measure in percent, but rather per-128 (the table size from the
// regexp macro assembler).
intptr_t Frequency(intptr_t in_character) {
ASSERT((in_character & RegExpMacroAssembler::kTableMask) == in_character);
if (total_samples_ < 1) return 1; // Division by zero.
intptr_t freq_in_per128 =
(frequencies_[in_character].counter() * 128) / total_samples_;
return freq_in_per128;
}
private:
class CharacterFrequency {
public:
CharacterFrequency() : counter_(0), character_(-1) {}
explicit CharacterFrequency(intptr_t character)
: counter_(0), character_(character) {}
void Increment() { counter_++; }
intptr_t counter() { return counter_; }
intptr_t character() { return character_; }
private:
intptr_t counter_;
intptr_t character_;
DISALLOW_ALLOCATION();
};
private:
CharacterFrequency frequencies_[RegExpMacroAssembler::kTableSize];
intptr_t total_samples_;
};
class RegExpCompiler : public ValueObject {
public:
RegExpCompiler(intptr_t capture_count, bool is_one_byte);
intptr_t AllocateRegister() { return next_register_++; }
// Lookarounds to match lone surrogates for unicode character class matches
// are never nested. We can therefore reuse registers.
intptr_t UnicodeLookaroundStackRegister() {
if (unicode_lookaround_stack_register_ == kNoRegister) {
unicode_lookaround_stack_register_ = AllocateRegister();
}
return unicode_lookaround_stack_register_;
}
intptr_t UnicodeLookaroundPositionRegister() {
if (unicode_lookaround_position_register_ == kNoRegister) {
unicode_lookaround_position_register_ = AllocateRegister();
}
return unicode_lookaround_position_register_;
}
#if !defined(DART_PRECOMPILED_RUNTIME)
RegExpEngine::CompilationResult Assemble(IRRegExpMacroAssembler* assembler,
RegExpNode* start,
intptr_t capture_count,
const String& pattern);
#endif
RegExpEngine::CompilationResult Assemble(
BytecodeRegExpMacroAssembler* assembler,
RegExpNode* start,
intptr_t capture_count,
const String& pattern);
inline void AddWork(RegExpNode* node) { work_list_->Add(node); }
static constexpr intptr_t kImplementationOffset = 0;
static constexpr intptr_t kNumberOfRegistersOffset = 0;
static constexpr intptr_t kCodeOffset = 1;
RegExpMacroAssembler* macro_assembler() { return macro_assembler_; }
EndNode* accept() { return accept_; }
static constexpr intptr_t kMaxRecursion = 100;
inline intptr_t recursion_depth() { return recursion_depth_; }
inline void IncrementRecursionDepth() { recursion_depth_++; }
inline void DecrementRecursionDepth() { recursion_depth_--; }
void SetRegExpTooBig() { reg_exp_too_big_ = true; }
inline bool one_byte() const { return is_one_byte_; }
bool read_backward() { return read_backward_; }
void set_read_backward(bool value) { read_backward_ = value; }
FrequencyCollator* frequency_collator() { return &frequency_collator_; }
intptr_t current_expansion_factor() { return current_expansion_factor_; }
void set_current_expansion_factor(intptr_t value) {
current_expansion_factor_ = value;
}
Zone* zone() const { return zone_; }
static constexpr intptr_t kNoRegister = -1;
private:
EndNode* accept_;
intptr_t next_register_;
intptr_t unicode_lookaround_stack_register_;
intptr_t unicode_lookaround_position_register_;
ZoneGrowableArray<RegExpNode*>* work_list_;
intptr_t recursion_depth_;
RegExpMacroAssembler* macro_assembler_;
bool is_one_byte_;
bool reg_exp_too_big_;
bool read_backward_;
intptr_t current_expansion_factor_;
FrequencyCollator frequency_collator_;
Zone* zone_;
};
class RecursionCheck : public ValueObject {
public:
explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) {
compiler->IncrementRecursionDepth();
}
~RecursionCheck() { compiler_->DecrementRecursionDepth(); }
private:
RegExpCompiler* compiler_;
};
static RegExpEngine::CompilationResult IrregexpRegExpTooBig() {
return RegExpEngine::CompilationResult("RegExp too big");
}
// Attempts to compile the regexp using an Irregexp code generator. Returns
// a fixed array or a null handle depending on whether it succeeded.
RegExpCompiler::RegExpCompiler(intptr_t capture_count, bool is_one_byte)
: next_register_(2 * (capture_count + 1)),
unicode_lookaround_stack_register_(kNoRegister),
unicode_lookaround_position_register_(kNoRegister),
work_list_(nullptr),
recursion_depth_(0),
is_one_byte_(is_one_byte),
reg_exp_too_big_(false),
read_backward_(false),
current_expansion_factor_(1),
zone_(Thread::Current()->zone()) {
accept_ = new (Z) EndNode(EndNode::ACCEPT, Z);
}
#if !defined(DART_PRECOMPILED_RUNTIME)
RegExpEngine::CompilationResult RegExpCompiler::Assemble(
IRRegExpMacroAssembler* macro_assembler,
RegExpNode* start,
intptr_t capture_count,
const String& pattern) {
macro_assembler->set_slow_safe(false /* use_slow_safe_regexp_compiler */);
macro_assembler_ = macro_assembler;
ZoneGrowableArray<RegExpNode*> work_list(0);
work_list_ = &work_list;
BlockLabel fail;
macro_assembler_->PushBacktrack(&fail);
Trace new_trace;
start->Emit(this, &new_trace);
macro_assembler_->BindBlock(&fail);
macro_assembler_->Fail();
while (!work_list.is_empty()) {
work_list.RemoveLast()->Emit(this, &new_trace);
}
if (reg_exp_too_big_) return IrregexpRegExpTooBig();
macro_assembler->GenerateBacktrackBlock();
macro_assembler->FinalizeRegistersArray();
return RegExpEngine::CompilationResult(
macro_assembler->backtrack_goto(), macro_assembler->graph_entry(),
macro_assembler->num_blocks(), macro_assembler->num_stack_locals(),
next_register_);
}
#endif
RegExpEngine::CompilationResult RegExpCompiler::Assemble(
BytecodeRegExpMacroAssembler* macro_assembler,
RegExpNode* start,
intptr_t capture_count,
const String& pattern) {
macro_assembler->set_slow_safe(false /* use_slow_safe_regexp_compiler */);
macro_assembler_ = macro_assembler;
ZoneGrowableArray<RegExpNode*> work_list(0);
work_list_ = &work_list;
BlockLabel fail;
macro_assembler_->PushBacktrack(&fail);
Trace new_trace;
start->Emit(this, &new_trace);
macro_assembler_->BindBlock(&fail);
macro_assembler_->Fail();
while (!work_list.is_empty()) {
work_list.RemoveLast()->Emit(this, &new_trace);
}
if (reg_exp_too_big_) return IrregexpRegExpTooBig();
TypedData& bytecode = TypedData::ZoneHandle(macro_assembler->GetBytecode());
return RegExpEngine::CompilationResult(&bytecode, next_register_);
}
bool Trace::DeferredAction::Mentions(intptr_t that) {
if (action_type() == ActionNode::CLEAR_CAPTURES) {
Interval range = static_cast<DeferredClearCaptures*>(this)->range();
return range.Contains(that);
} else {
return reg() == that;
}
}
bool Trace::mentions_reg(intptr_t reg) {
for (DeferredAction* action = actions_; action != nullptr;
action = action->next()) {
if (action->Mentions(reg)) return true;
}
return false;
}
bool Trace::GetStoredPosition(intptr_t reg, intptr_t* cp_offset) {
ASSERT(*cp_offset == 0);
for (DeferredAction* action = actions_; action != nullptr;
action = action->next()) {
if (action->Mentions(reg)) {
if (action->action_type() == ActionNode::STORE_POSITION) {
*cp_offset = static_cast<DeferredCapture*>(action)->cp_offset();
return true;
} else {
return false;
}
}
}
return false;
}
// This is called as we come into a loop choice node and some other tricky
// nodes. It normalizes the state of the code generator to ensure we can
// generate generic code.
intptr_t Trace::FindAffectedRegisters(OutSet* affected_registers, Zone* zone) {
intptr_t max_register = RegExpCompiler::kNoRegister;
for (DeferredAction* action = actions_; action != nullptr;
action = action->next()) {
if (action->action_type() == ActionNode::CLEAR_CAPTURES) {
Interval range = static_cast<DeferredClearCaptures*>(action)->range();
for (intptr_t i = range.from(); i <= range.to(); i++)
affected_registers->Set(i, zone);
if (range.to() > max_register) max_register = range.to();
} else {
affected_registers->Set(action->reg(), zone);
if (action->reg() > max_register) max_register = action->reg();
}
}
return max_register;
}
void Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler,
intptr_t max_register,
const OutSet& registers_to_pop,
const OutSet& registers_to_clear) {
for (intptr_t reg = max_register; reg >= 0; reg--) {
if (registers_to_pop.Get(reg)) {
assembler->PopRegister(reg);
} else if (registers_to_clear.Get(reg)) {
intptr_t clear_to = reg;
while (reg > 0 && registers_to_clear.Get(reg - 1)) {
reg--;
}
assembler->ClearRegisters(reg, clear_to);
}
}
}
void Trace::PerformDeferredActions(RegExpMacroAssembler* assembler,
intptr_t max_register,
const OutSet& affected_registers,
OutSet* registers_to_pop,
OutSet* registers_to_clear,
Zone* zone) {
for (intptr_t reg = 0; reg <= max_register; reg++) {
if (!affected_registers.Get(reg)) {
continue;
}
// The chronologically first deferred action in the trace
// is used to infer the action needed to restore a register
// to its previous state (or not, if it's safe to ignore it).
enum DeferredActionUndoType { ACTION_IGNORE, ACTION_RESTORE, ACTION_CLEAR };
DeferredActionUndoType undo_action = ACTION_IGNORE;
intptr_t value = 0;
bool absolute = false;
bool clear = false;
const intptr_t kNoStore = kMinInt32;
intptr_t store_position = kNoStore;
// This is a little tricky because we are scanning the actions in reverse
// historical order (newest first).
for (DeferredAction* action = actions_; action != nullptr;
action = action->next()) {
if (action->Mentions(reg)) {
switch (action->action_type()) {
case ActionNode::SET_REGISTER: {
Trace::DeferredSetRegister* psr =
static_cast<Trace::DeferredSetRegister*>(action);
if (!absolute) {
value += psr->value();
absolute = true;
}
// SET_REGISTER is currently only used for newly introduced loop
// counters. They can have a significant previous value if they
// occur in a loop. TODO(lrn): Propagate this information, so we
// can set undo_action to ACTION_IGNORE if we know there is no
// value to restore.
undo_action = ACTION_RESTORE;
ASSERT(store_position == kNoStore);
ASSERT(!clear);
break;
}
case ActionNode::INCREMENT_REGISTER:
if (!absolute) {
value++;
}
ASSERT(store_position == kNoStore);
ASSERT(!clear);
undo_action = ACTION_RESTORE;
break;
case ActionNode::STORE_POSITION: {
Trace::DeferredCapture* pc =
static_cast<Trace::DeferredCapture*>(action);
if (!clear && store_position == kNoStore) {
store_position = pc->cp_offset();
}
// For captures we know that stores and clears alternate.
// Other register, are never cleared, and if the occur
// inside a loop, they might be assigned more than once.
if (reg <= 1) {
// Registers zero and one, aka "capture zero", is
// always set correctly if we succeed. There is no
// need to undo a setting on backtrack, because we
// will set it again or fail.
undo_action = ACTION_IGNORE;
} else {
undo_action = pc->is_capture() ? ACTION_CLEAR : ACTION_RESTORE;
}
ASSERT(!absolute);
ASSERT(value == 0);
break;
}
case ActionNode::CLEAR_CAPTURES: {
// Since we're scanning in reverse order, if we've already
// set the position we have to ignore historically earlier
// clearing operations.
if (store_position == kNoStore) {
clear = true;
}
undo_action = ACTION_RESTORE;
ASSERT(!absolute);
ASSERT(value == 0);
break;
}
default:
UNREACHABLE();
break;
}
}
}
// Prepare for the undo-action (e.g., push if it's going to be popped).
if (undo_action == ACTION_RESTORE) {
assembler->PushRegister(reg);
registers_to_pop->Set(reg, zone);
} else if (undo_action == ACTION_CLEAR) {
registers_to_clear->Set(reg, zone);
}
// Perform the chronologically last action (or accumulated increment)
// for the register.
if (store_position != kNoStore) {
assembler->WriteCurrentPositionToRegister(reg, store_position);
} else if (clear) {
assembler->ClearRegisters(reg, reg);
} else if (absolute) {
assembler->SetRegister(reg, value);
} else if (value != 0) {
assembler->AdvanceRegister(reg, value);
}
}
}
// This is called as we come into a loop choice node and some other tricky
// nodes. It normalizes the state of the code generator to ensure we can
// generate generic code.
void Trace::Flush(RegExpCompiler* compiler, RegExpNode* successor) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
ASSERT(!is_trivial());
if (actions_ == nullptr && backtrack() == nullptr) {
// Here we just have some deferred cp advances to fix and we are back to
// a normal situation. We may also have to forget some information gained
// through a quick check that was already performed.
if (cp_offset_ != 0) assembler->AdvanceCurrentPosition(cp_offset_);
// Create a new trivial state and generate the node with that.
Trace new_state;
successor->Emit(compiler, &new_state);
return;
}
// Generate deferred actions here along with code to undo them again.
OutSet affected_registers;
if (backtrack() != nullptr) {
// Here we have a concrete backtrack location. These are set up by choice
// nodes and so they indicate that we have a deferred save of the current
// position which we may need to emit here.
assembler->PushCurrentPosition();
}
Zone* zone = successor->zone();
intptr_t max_register = FindAffectedRegisters(&affected_registers, zone);
OutSet registers_to_pop;
OutSet registers_to_clear;
PerformDeferredActions(assembler, max_register, affected_registers,
&registers_to_pop, &registers_to_clear, zone);
if (cp_offset_ != 0) {
assembler->AdvanceCurrentPosition(cp_offset_);
}
// Create a new trivial state and generate the node with that.
BlockLabel undo;
assembler->PushBacktrack(&undo);
Trace new_state;
successor->Emit(compiler, &new_state);
// On backtrack we need to restore state.
assembler->BindBlock(&undo);
RestoreAffectedRegisters(assembler, max_register, registers_to_pop,
registers_to_clear);
if (backtrack() == nullptr) {
assembler->Backtrack();
} else {
assembler->PopCurrentPosition();
assembler->GoTo(backtrack());
}
}
void NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
// Omit flushing the trace. We discard the entire stack frame anyway.
if (!label()->is_bound()) {
// We are completely independent of the trace, since we ignore it,
// so this code can be used as the generic version.
assembler->BindBlock(label());
}
// Throw away everything on the backtrack stack since the start
// of the negative submatch and restore the character position.
assembler->ReadCurrentPositionFromRegister(current_position_register_);
assembler->ReadStackPointerFromRegister(stack_pointer_register_);
if (clear_capture_count_ > 0) {
// Clear any captures that might have been performed during the success
// of the body of the negative look-ahead.
int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1;
assembler->ClearRegisters(clear_capture_start_, clear_capture_end);
}
// Now that we have unwound the stack we find at the top of the stack the
// backtrack that the BeginSubmatch node got.
assembler->Backtrack();
}
void EndNode::Emit(RegExpCompiler* compiler, Trace* trace) {
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (!label()->is_bound()) {
assembler->BindBlock(label());
}
switch (action_) {
case ACCEPT:
assembler->Succeed();
return;
case BACKTRACK:
assembler->GoTo(trace->backtrack());
return;
case NEGATIVE_SUBMATCH_SUCCESS:
// This case is handled in a different virtual method.
UNREACHABLE();
}
UNIMPLEMENTED();
}
void GuardedAlternative::AddGuard(Guard* guard, Zone* zone) {
if (guards_ == nullptr) guards_ = new (zone) ZoneGrowableArray<Guard*>(1);
guards_->Add(guard);
}
ActionNode* ActionNode::SetRegister(intptr_t reg,
intptr_t val,
RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(SET_REGISTER, on_success);
result->data_.u_store_register.reg = reg;
result->data_.u_store_register.value = val;
return result;
}
ActionNode* ActionNode::IncrementRegister(intptr_t reg,
RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(INCREMENT_REGISTER, on_success);
result->data_.u_increment_register.reg = reg;
return result;
}
ActionNode* ActionNode::StorePosition(intptr_t reg,
bool is_capture,
RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(STORE_POSITION, on_success);
result->data_.u_position_register.reg = reg;
result->data_.u_position_register.is_capture = is_capture;
return result;
}
ActionNode* ActionNode::ClearCaptures(Interval range, RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(CLEAR_CAPTURES, on_success);
result->data_.u_clear_captures.range_from = range.from();
result->data_.u_clear_captures.range_to = range.to();
return result;
}
ActionNode* ActionNode::BeginSubmatch(intptr_t stack_reg,
intptr_t position_reg,
RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(BEGIN_SUBMATCH, on_success);
result->data_.u_submatch.stack_pointer_register = stack_reg;
result->data_.u_submatch.current_position_register = position_reg;
return result;
}
ActionNode* ActionNode::PositiveSubmatchSuccess(intptr_t stack_reg,
intptr_t position_reg,
intptr_t clear_register_count,
intptr_t clear_register_from,
RegExpNode* on_success) {
ActionNode* result = new (on_success->zone())
ActionNode(POSITIVE_SUBMATCH_SUCCESS, on_success);
result->data_.u_submatch.stack_pointer_register = stack_reg;
result->data_.u_submatch.current_position_register = position_reg;
result->data_.u_submatch.clear_register_count = clear_register_count;
result->data_.u_submatch.clear_register_from = clear_register_from;
return result;
}
ActionNode* ActionNode::EmptyMatchCheck(intptr_t start_register,
intptr_t repetition_register,
intptr_t repetition_limit,
RegExpNode* on_success) {
ActionNode* result =
new (on_success->zone()) ActionNode(EMPTY_MATCH_CHECK, on_success);
result->data_.u_empty_match_check.start_register = start_register;
result->data_.u_empty_match_check.repetition_register = repetition_register;
result->data_.u_empty_match_check.repetition_limit = repetition_limit;
return result;
}
#define DEFINE_ACCEPT(Type) \
void Type##Node::Accept(NodeVisitor* visitor) { \
visitor->Visit##Type(this); \
}
FOR_EACH_NODE_TYPE(DEFINE_ACCEPT)
#undef DEFINE_ACCEPT
void LoopChoiceNode::Accept(NodeVisitor* visitor) {
visitor->VisitLoopChoice(this);
}
// -------------------------------------------------------------------
// Emit code.
void ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler,
Guard* guard,
Trace* trace) {
switch (guard->op()) {
case Guard::LT:
ASSERT(!trace->mentions_reg(guard->reg()));
macro_assembler->IfRegisterGE(guard->reg(), guard->value(),
trace->backtrack());
break;
case Guard::GEQ:
ASSERT(!trace->mentions_reg(guard->reg()));
macro_assembler->IfRegisterLT(guard->reg(), guard->value(),
trace->backtrack());
break;
}
}
// Returns the number of characters in the equivalence class, omitting those
// that cannot occur in the source string because it is ASCII.
static intptr_t GetCaseIndependentLetters(uint16_t character,
bool one_byte_subject,
int32_t* letters) {
unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize;
intptr_t length = jsregexp_uncanonicalize.get(character, '\0', letters);
// Unibrow returns 0 or 1 for characters where case independence is
// trivial.
if (length == 0) {
letters[0] = character;
length = 1;
}
if (!one_byte_subject || character <= Symbols::kMaxOneCharCodeSymbol) {
return length;
}
// The standard requires that non-ASCII characters cannot have ASCII
// character codes in their equivalence class.
// TODO(dcarney): issue 3550 this is not actually true for Latin1 anymore,
// is it? For example, \u00C5 is equivalent to \u212B.
return 0;
}
static inline bool EmitSimpleCharacter(Zone* zone,
RegExpCompiler* compiler,
uint16_t c,
BlockLabel* on_failure,
intptr_t cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
bool bound_checked = false;
if (!preloaded) {
assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
bound_checked = true;
}
assembler->CheckNotCharacter(c, on_failure);
return bound_checked;
}
// Only emits non-letters (things that don't have case). Only used for case
// independent matches.
static inline bool EmitAtomNonLetter(Zone* zone,
RegExpCompiler* compiler,
uint16_t c,
BlockLabel* on_failure,
intptr_t cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
bool one_byte = compiler->one_byte();
int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
intptr_t length = GetCaseIndependentLetters(c, one_byte, chars);
if (length < 1) {
// This can't match. Must be an one-byte subject and a non-one-byte
// character. We do not need to do anything since the one-byte pass
// already handled this.
return false; // Bounds not checked.
}
bool checked = false;
// We handle the length > 1 case in a later pass.
if (length == 1) {
if (one_byte && c > Symbols::kMaxOneCharCodeSymbol) {
// Can't match - see above.
return false; // Bounds not checked.
}
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
checked = check;
}
macro_assembler->CheckNotCharacter(c, on_failure);
}
return checked;
}
static bool ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler,
bool one_byte,
uint16_t c1,
uint16_t c2,
BlockLabel* on_failure) {
uint16_t char_mask;
if (one_byte) {
char_mask = Symbols::kMaxOneCharCodeSymbol;
} else {
char_mask = Utf16::kMaxCodeUnit;
}
uint16_t exor = c1 ^ c2;
// Check whether exor has only one bit set.
if (((exor - 1) & exor) == 0) {
// If c1 and c2 differ only by one bit.
// Ecma262UnCanonicalize always gives the highest number last.
ASSERT(c2 > c1);
uint16_t mask = char_mask ^ exor;
macro_assembler->CheckNotCharacterAfterAnd(c1, mask, on_failure);
return true;
}
ASSERT(c2 > c1);
uint16_t diff = c2 - c1;
if (((diff - 1) & diff) == 0 && c1 >= diff) {
// If the characters differ by 2^n but don't differ by one bit then
// subtract the difference from the found character, then do the or
// trick. We avoid the theoretical case where negative numbers are
// involved in order to simplify code generation.
uint16_t mask = char_mask ^ diff;
macro_assembler->CheckNotCharacterAfterMinusAnd(c1 - diff, diff, mask,
on_failure);
return true;
}
return false;
}
typedef bool EmitCharacterFunction(Zone* zone,
RegExpCompiler* compiler,
uint16_t c,
BlockLabel* on_failure,
intptr_t cp_offset,
bool check,
bool preloaded);
// Only emits letters (things that have case). Only used for case independent
// matches.
static inline bool EmitAtomLetter(Zone* zone,
RegExpCompiler* compiler,
uint16_t c,
BlockLabel* on_failure,
intptr_t cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
bool one_byte = compiler->one_byte();
int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
intptr_t length = GetCaseIndependentLetters(c, one_byte, chars);
if (length <= 1) return false;
// We may not need to check against the end of the input string
// if this character lies before a character that matched.
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
}
BlockLabel ok;
ASSERT(unibrow::Ecma262UnCanonicalize::kMaxWidth == 4);
switch (length) {
case 2: {
if (ShortCutEmitCharacterPair(macro_assembler, one_byte, chars[0],
chars[1], on_failure)) {
} else {
macro_assembler->CheckCharacter(chars[0], &ok);
macro_assembler->CheckNotCharacter(chars[1], on_failure);
macro_assembler->BindBlock(&ok);
}
break;
}
case 4:
macro_assembler->CheckCharacter(chars[3], &ok);
FALL_THROUGH;
case 3:
macro_assembler->CheckCharacter(chars[0], &ok);
macro_assembler->CheckCharacter(chars[1], &ok);
macro_assembler->CheckNotCharacter(chars[2], on_failure);
macro_assembler->BindBlock(&ok);
break;
default:
UNREACHABLE();
break;
}
return true;
}
static void EmitBoundaryTest(RegExpMacroAssembler* masm,
uint16_t border,
BlockLabel* fall_through,
BlockLabel* above_or_equal,
BlockLabel* below) {
if (below != fall_through) {
masm->CheckCharacterLT(border, below);
if (above_or_equal != fall_through) masm->GoTo(above_or_equal);
} else {
masm->CheckCharacterGT(border - 1, above_or_equal);
}
}
static void EmitDoubleBoundaryTest(RegExpMacroAssembler* masm,
uint16_t first,
uint16_t last,
BlockLabel* fall_through,
BlockLabel* in_range,
BlockLabel* out_of_range) {
if (in_range == fall_through) {
if (first == last) {
masm->CheckNotCharacter(first, out_of_range);
} else {
masm->CheckCharacterNotInRange(first, last, out_of_range);
}
} else {
if (first == last) {
masm->CheckCharacter(first, in_range);
} else {
masm->CheckCharacterInRange(first, last, in_range);
}
if (out_of_range != fall_through) masm->GoTo(out_of_range);
}
}
// even_label is for ranges[i] to ranges[i + 1] where i - start_index is even.
// odd_label is for ranges[i] to ranges[i + 1] where i - start_index is odd.
static void EmitUseLookupTable(RegExpMacroAssembler* masm,
ZoneGrowableArray<uint16_t>* ranges,
intptr_t start_index,
intptr_t end_index,
uint16_t min_char,
BlockLabel* fall_through,
BlockLabel* even_label,
BlockLabel* odd_label) {
const intptr_t kSize = RegExpMacroAssembler::kTableSize;
const intptr_t kMask = RegExpMacroAssembler::kTableMask;
intptr_t base = (min_char & ~kMask);
// Assert that everything is on one kTableSize page.
for (intptr_t i = start_index; i <= end_index; i++) {
ASSERT((ranges->At(i) & ~kMask) == base);
}
ASSERT(start_index == 0 || (ranges->At(start_index - 1) & ~kMask) <= base);
char templ[kSize];
BlockLabel* on_bit_set;
BlockLabel* on_bit_clear;
intptr_t bit;
if (even_label == fall_through) {
on_bit_set = odd_label;
on_bit_clear = even_label;
bit = 1;
} else {
on_bit_set = even_label;
on_bit_clear = odd_label;
bit = 0;
}
for (intptr_t i = 0; i < (ranges->At(start_index) & kMask) && i < kSize;
i++) {
templ[i] = bit;
}
intptr_t j = 0;
bit ^= 1;
for (intptr_t i = start_index; i < end_index; i++) {
for (j = (ranges->At(i) & kMask); j < (ranges->At(i + 1) & kMask); j++) {
templ[j] = bit;
}
bit ^= 1;
}
for (intptr_t i = j; i < kSize; i++) {
templ[i] = bit;
}
// TODO(erikcorry): Cache these.
const TypedData& ba = TypedData::ZoneHandle(
masm->zone(), TypedData::New(kTypedDataUint8ArrayCid, kSize, Heap::kOld));
for (intptr_t i = 0; i < kSize; i++) {
ba.SetUint8(i, templ[i]);
}
masm->CheckBitInTable(ba, on_bit_set);
if (on_bit_clear != fall_through) masm->GoTo(on_bit_clear);
}
static void CutOutRange(RegExpMacroAssembler* masm,
ZoneGrowableArray<uint16_t>* ranges,
intptr_t start_index,
intptr_t end_index,
intptr_t cut_index,
BlockLabel* even_label,
BlockLabel* odd_label) {
bool odd = (((cut_index - start_index) & 1) == 1);
BlockLabel* in_range_label = odd ? odd_label : even_label;
BlockLabel dummy;
EmitDoubleBoundaryTest(masm, ranges->At(cut_index),
ranges->At(cut_index + 1) - 1, &dummy, in_range_label,
&dummy);
ASSERT(!dummy.is_linked());
// Cut out the single range by rewriting the array. This creates a new
// range that is a merger of the two ranges on either side of the one we
// are cutting out. The oddity of the labels is preserved.
for (intptr_t j = cut_index; j > start_index; j--) {
(*ranges)[j] = ranges->At(j - 1);
}
for (intptr_t j = cut_index + 1; j < end_index; j++) {
(*ranges)[j] = ranges->At(j + 1);
}
}
// Unicode case. Split the search space into kSize spaces that are handled
// with recursion.
static void SplitSearchSpace(ZoneGrowableArray<uint16_t>* ranges,
intptr_t start_index,
intptr_t end_index,
intptr_t* new_start_index,
intptr_t* new_end_index,
uint16_t* border) {
const intptr_t kSize = RegExpMacroAssembler::kTableSize;
const intptr_t kMask = RegExpMacroAssembler::kTableMask;
uint16_t first = ranges->At(start_index);
uint16_t last = ranges->At(end_index) - 1;
*new_start_index = start_index;
*border = (ranges->At(start_index) & ~kMask) + kSize;
while (*new_start_index < end_index) {
if (ranges->At(*new_start_index) > *border) break;
(*new_start_index)++;
}
// new_start_index is the index of the first edge that is beyond the
// current kSize space.
// For very large search spaces we do a binary chop search of the non-Latin1
// space instead of just going to the end of the current kSize space. The
// heuristics are complicated a little by the fact that any 128-character
// encoding space can be quickly tested with a table lookup, so we don't
// wish to do binary chop search at a smaller granularity than that. A
// 128-character space can take up a lot of space in the ranges array if,
// for example, we only want to match every second character (eg. the lower
// case characters on some Unicode pages).
intptr_t binary_chop_index = (end_index + start_index) / 2;
// The first test ensures that we get to the code that handles the Latin1
// range with a single not-taken branch, speeding up this important
// character range (even non-Latin1 charset-based text has spaces and
// punctuation).
if (*border - 1 > Symbols::kMaxOneCharCodeSymbol && // Latin1 case.
end_index - start_index > (*new_start_index - start_index) * 2 &&
last - first > kSize * 2 && binary_chop_index > *new_start_index &&
ranges->At(binary_chop_index) >= first + 2 * kSize) {
intptr_t scan_forward_for_section_border = binary_chop_index;
intptr_t new_border = (ranges->At(binary_chop_index) | kMask) + 1;
while (scan_forward_for_section_border < end_index) {
if (ranges->At(scan_forward_for_section_border) > new_border) {
*new_start_index = scan_forward_for_section_border;
*border = new_border;
break;
}
scan_forward_for_section_border++;
}
}
ASSERT(*new_start_index > start_index);
*new_end_index = *new_start_index - 1;
if (ranges->At(*new_end_index) == *border) {
(*new_end_index)--;
}
if (*border >= ranges->At(end_index)) {
*border = ranges->At(end_index);
*new_start_index = end_index; // Won't be used.
*new_end_index = end_index - 1;
}
}
// Gets a series of segment boundaries representing a character class. If the
// character is in the range between an even and an odd boundary (counting from
// start_index) then go to even_label, otherwise go to odd_label. We already
// know that the character is in the range of min_char to max_char inclusive.
// Either label can be null indicating backtracking. Either label can also be
// equal to the fall_through label.
static void GenerateBranches(RegExpMacroAssembler* masm,
ZoneGrowableArray<uint16_t>* ranges,
intptr_t start_index,
intptr_t end_index,
uint16_t min_char,
uint16_t max_char,
BlockLabel* fall_through,
BlockLabel* even_label,
BlockLabel* odd_label) {
uint16_t first = ranges->At(start_index);
uint16_t last = ranges->At(end_index) - 1;
ASSERT(min_char < first);
// Just need to test if the character is before or on-or-after
// a particular character.
if (start_index == end_index) {
EmitBoundaryTest(masm, first, fall_through, even_label, odd_label);
return;
}
// Another almost trivial case: There is one interval in the middle that is
// different from the end intervals.
if (start_index + 1 == end_index) {
EmitDoubleBoundaryTest(masm, first, last, fall_through, even_label,
odd_label);
return;
}
// It's not worth using table lookup if there are very few intervals in the
// character class.
if (end_index - start_index <= 6) {
// It is faster to test for individual characters, so we look for those
// first, then try arbitrary ranges in the second round.
static intptr_t kNoCutIndex = -1;
intptr_t cut = kNoCutIndex;
for (intptr_t i = start_index; i < end_index; i++) {
if (ranges->At(i) == ranges->At(i + 1) - 1) {
cut = i;
break;
}
}
if (cut == kNoCutIndex) cut = start_index;
CutOutRange(masm, ranges, start_index, end_index, cut, even_label,
odd_label);
ASSERT(end_index - start_index >= 2);
GenerateBranches(masm, ranges, start_index + 1, end_index - 1, min_char,
max_char, fall_through, even_label, odd_label);
return;
}
// If there are a lot of intervals in the regexp, then we will use tables to
// determine whether the character is inside or outside the character class.
const intptr_t kBits = RegExpMacroAssembler::kTableSizeBits;
if ((max_char >> kBits) == (min_char >> kBits)) {
EmitUseLookupTable(masm, ranges, start_index, end_index, min_char,
fall_through, even_label, odd_label);
return;
}
if ((min_char >> kBits) != (first >> kBits)) {
masm->CheckCharacterLT(first, odd_label);
GenerateBranches(masm, ranges, start_index + 1, end_index, first, max_char,
fall_through, odd_label, even_label);
return;
}
intptr_t new_start_index = 0;
intptr_t new_end_index = 0;
uint16_t border = 0;
SplitSearchSpace(ranges, start_index, end_index, &new_start_index,
&new_end_index, &border);
BlockLabel handle_rest;
BlockLabel* above = &handle_rest;
if (border == last + 1) {
// We didn't find any section that started after the limit, so everything
// above the border is one of the terminal labels.
above = (end_index & 1) != (start_index & 1) ? odd_label : even_label;
ASSERT(new_end_index == end_index - 1);
}
ASSERT(start_index <= new_end_index);
ASSERT(new_start_index <= end_index);
ASSERT(start_index < new_start_index);
ASSERT(new_end_index < end_index);
ASSERT(new_end_index + 1 == new_start_index ||
(new_end_index + 2 == new_start_index &&
border == ranges->At(new_end_index + 1)));
ASSERT(min_char < border - 1);
ASSERT(border < max_char);
ASSERT(ranges->At(new_end_index) < border);
ASSERT(border < ranges->At(new_start_index) ||
(border == ranges->At(new_start_index) &&
new_start_index == end_index && new_end_index == end_index - 1 &&
border == last + 1));
ASSERT(new_start_index == 0 || border >= ranges->At(new_start_index - 1));
masm->CheckCharacterGT(border - 1, above);
BlockLabel dummy;
GenerateBranches(masm, ranges, start_index, new_end_index, min_char,
border - 1, &dummy, even_label, odd_label);
if (handle_rest.is_linked()) {
masm->BindBlock(&handle_rest);
bool flip = (new_start_index & 1) != (start_index & 1);
GenerateBranches(masm, ranges, new_start_index, end_index, border, max_char,
&dummy, flip ? odd_label : even_label,
flip ? even_label : odd_label);
}
}
static void EmitCharClass(RegExpMacroAssembler* macro_assembler,
RegExpCharacterClass* cc,
bool one_byte,
BlockLabel* on_failure,
intptr_t cp_offset,
bool check_offset,
bool preloaded,
Zone* zone) {
ZoneGrowableArray<CharacterRange>* ranges = cc->ranges();
if (!CharacterRange::IsCanonical(ranges)) {
CharacterRange::Canonicalize(ranges);
}
uint16_t max_char;
if (one_byte) {
max_char = Symbols::kMaxOneCharCodeSymbol;
} else {
max_char = Utf16::kMaxCodeUnit;
}
intptr_t range_count = ranges->length();
intptr_t last_valid_range = range_count - 1;
while (last_valid_range >= 0) {
const CharacterRange& range = ranges->At(last_valid_range);
if (range.from() <= max_char) {
break;
}
last_valid_range--;
}
if (last_valid_range < 0) {
if (!cc->is_negated()) {
macro_assembler->GoTo(on_failure);
}
if (check_offset) {
macro_assembler->CheckPosition(cp_offset, on_failure);
}
return;
}
if (last_valid_range == 0 && ranges->At(0).IsEverything(max_char)) {
if (cc->is_negated()) {
macro_assembler->GoTo(on_failure);
} else {
// This is a common case hit by non-anchored expressions.
if (check_offset) {
macro_assembler->CheckPosition(cp_offset, on_failure);
}
}
return;
}
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
}
if (cc->is_standard() && macro_assembler->CheckSpecialCharacterClass(
cc->standard_type(), on_failure)) {
return;
}
// A new list with ascending entries. Each entry is a code unit
// where there is a boundary between code units that are part of
// the class and code units that are not. Normally we insert an
// entry at zero which goes to the failure label, but if there
// was already one there we fall through for success on that entry.
// Subsequent entries have alternating meaning (success/failure).
ZoneGrowableArray<uint16_t>* range_boundaries =
new (zone) ZoneGrowableArray<uint16_t>(last_valid_range);
bool zeroth_entry_is_failure = !cc->is_negated();
for (intptr_t i = 0; i <= last_valid_range; i++) {
const CharacterRange& range = ranges->At(i);
if (range.from() == 0) {
ASSERT(i == 0);
zeroth_entry_is_failure = !zeroth_entry_is_failure;
} else {
range_boundaries->Add(range.from());
}
if (range.to() + 1 <= max_char) {
range_boundaries->Add(range.to() + 1);
}
}
intptr_t end_index = range_boundaries->length() - 1;
BlockLabel fall_through;
GenerateBranches(macro_assembler, range_boundaries,
0, // start_index.
end_index,
0, // min_char.
max_char, &fall_through,
zeroth_entry_is_failure ? &fall_through : on_failure,
zeroth_entry_is_failure ? on_failure : &fall_through);
macro_assembler->BindBlock(&fall_through);
}
RegExpNode::~RegExpNode() {}
RegExpNode::LimitResult RegExpNode::LimitVersions(RegExpCompiler* compiler,
Trace* trace) {
// If we are generating a greedy loop then don't stop and don't reuse code.
if (trace->stop_node() != nullptr) {
return CONTINUE;
}
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
if (trace->is_trivial()) {
if (label_.is_bound()) {
// We are being asked to generate a generic version, but that's already
// been done so just go to it.
macro_assembler->GoTo(&label_);
return DONE;
}
if (compiler->recursion_depth() >= RegExpCompiler::kMaxRecursion) {
// To avoid too deep recursion we push the node to the work queue and just
// generate a goto here.
compiler->AddWork(this);
macro_assembler->GoTo(&label_);
return DONE;
}
// Generate generic version of the node and bind the label for later use.
macro_assembler->BindBlock(&label_);
return CONTINUE;
}
// We are being asked to make a non-generic version. Keep track of how many
// non-generic versions we generate so as not to overdo it.
trace_count_++;
if (kRegexpOptimization && trace_count_ < kMaxCopiesCodeGenerated &&
compiler->recursion_depth() <= RegExpCompiler::kMaxRecursion) {
return CONTINUE;
}
// If we get here code has been generated for this node too many times or
// recursion is too deep. Time to switch to a generic version. The code for
// generic versions above can handle deep recursion properly.
trace->Flush(compiler, this);
return DONE;
}
intptr_t ActionNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
if (budget <= 0) return 0;
if (action_type_ == POSITIVE_SUBMATCH_SUCCESS) return 0; // Rewinds input!
return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start);
}
void ActionNode::FillInBMInfo(intptr_t offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
if (action_type_ == BEGIN_SUBMATCH) {
bm->SetRest(offset);
} else if (action_type_ != POSITIVE_SUBMATCH_SUCCESS) {
on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start);
}
SaveBMInfo(bm, not_at_start, offset);
}
intptr_t AssertionNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
if (budget <= 0) return 0;
// If we know we are not at the start and we are asked "how many characters
// will you match if you succeed?" then we can answer anything since false
// implies false. So lets just return the max answer (still_to_find) since
// that won't prevent us from preloading a lot of characters for the other
// branches in the node graph.
if (assertion_type() == AT_START && not_at_start) return still_to_find;
return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start);
}
void AssertionNode::FillInBMInfo(intptr_t offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
// Match the behaviour of EatsAtLeast on this node.
if (assertion_type() == AT_START && not_at_start) return;
on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start);
SaveBMInfo(bm, not_at_start, offset);
}
intptr_t BackReferenceNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
if (read_backward()) return 0;
if (budget <= 0) return 0;
return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start);
}
intptr_t TextNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
if (read_backward()) return 0;
intptr_t answer = Length();
if (answer >= still_to_find) return answer;
if (budget <= 0) return answer;
// We are not at start after this node so we set the last argument to 'true'.
return answer +
on_success()->EatsAtLeast(still_to_find - answer, budget - 1, true);
}
intptr_t NegativeLookaroundChoiceNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
if (budget <= 0) return 0;
// Alternative 0 is the negative lookahead, alternative 1 is what comes
// afterwards.
RegExpNode* node = (*alternatives_)[1].node();
return node->EatsAtLeast(still_to_find, budget - 1, not_at_start);
}
void NegativeLookaroundChoiceNode::GetQuickCheckDetails(
QuickCheckDetails* details,
RegExpCompiler* compiler,
intptr_t filled_in,
bool not_at_start) {
// Alternative 0 is the negative lookahead, alternative 1 is what comes
// afterwards.
RegExpNode* node = (*alternatives_)[1].node();
return node->GetQuickCheckDetails(details, compiler, filled_in, not_at_start);
}
intptr_t ChoiceNode::EatsAtLeastHelper(intptr_t still_to_find,
intptr_t budget,
RegExpNode* ignore_this_node,
bool not_at_start) {
if (budget <= 0) return 0;
intptr_t min = 100;
intptr_t choice_count = alternatives_->length();
budget = (budget - 1) / choice_count;
for (intptr_t i = 0; i < choice_count; i++) {
RegExpNode* node = (*alternatives_)[i].node();
if (node == ignore_this_node) continue;
intptr_t node_eats_at_least =
node->EatsAtLeast(still_to_find, budget, not_at_start);
if (node_eats_at_least < min) min = node_eats_at_least;
if (min == 0) return 0;
}
return min;
}
intptr_t LoopChoiceNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
return EatsAtLeastHelper(still_to_find, budget - 1, loop_node_, not_at_start);
}
intptr_t ChoiceNode::EatsAtLeast(intptr_t still_to_find,
intptr_t budget,
bool not_at_start) {
return EatsAtLeastHelper(still_to_find, budget, nullptr, not_at_start);
}
// Takes the left-most 1-bit and smears it out, setting all bits to its right.
static inline uint32_t SmearBitsRight(uint32_t v) {
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
return v;
}
bool QuickCheckDetails::Rationalize(bool asc) {
bool found_useful_op = false;
uint32_t char_mask;
if (asc) {
char_mask = Symbols::kMaxOneCharCodeSymbol;
} else {
char_mask = Utf16::kMaxCodeUnit;
}
mask_ = 0;
value_ = 0;
intptr_t char_shift = 0;
for (intptr_t i = 0; i < characters_; i++) {
Position* pos = &positions_[i];
if ((pos->mask & Symbols::kMaxOneCharCodeSymbol) != 0) {
found_useful_op = true;
}
mask_ |= (pos->mask & char_mask) << char_shift;
value_ |= (pos->value & char_mask) << char_shift;
char_shift += asc ? 8 : 16;
}
return found_useful_op;
}
bool RegExpNode::EmitQuickCheck(RegExpCompiler* compiler,
Trace* bounds_check_trace,
Trace* trace,
bool preload_has_checked_bounds,
BlockLabel* on_possible_success,
QuickCheckDetails* details,
bool fall_through_on_failure) {
if (details->characters() == 0) return false;
GetQuickCheckDetails(details, compiler, 0,
trace->at_start() == Trace::FALSE_VALUE);
if (details->cannot_match()) return false;
if (!details->Rationalize(compiler->one_byte())) return false;
ASSERT(details->characters() == 1 ||
compiler->macro_assembler()->CanReadUnaligned());
uint32_t mask = details->mask();
uint32_t value = details->value();
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (trace->characters_preloaded() != details->characters()) {
ASSERT(trace->cp_offset() == bounds_check_trace->cp_offset());
// We are attempting to preload the minimum number of characters
// any choice would eat, so if the bounds check fails, then none of the
// choices can succeed, so we can just immediately backtrack, rather
// than go to the next choice.
assembler->LoadCurrentCharacter(
trace->cp_offset(), bounds_check_trace->backtrack(),
!preload_has_checked_bounds, details->characters());
}
bool need_mask = true;
if (details->characters() == 1) {
// If number of characters preloaded is 1 then we used a byte or 16 bit
// load so the value is already masked down.
uint32_t char_mask;
if (compiler->one_byte()) {
char_mask = Symbols::kMaxOneCharCodeSymbol;
} else {
char_mask = Utf16::kMaxCodeUnit;
}
if ((mask & char_mask) == char_mask) need_mask = false;
mask &= char_mask;
} else {
// For 2-character preloads in one-byte mode or 1-character preloads in
// two-byte mode we also use a 16 bit load with zero extend.
if (details->characters() == 2 && compiler->one_byte()) {
if ((mask & 0xffff) == 0xffff) need_mask = false;
} else if (details->characters() == 1 && !compiler->one_byte()) {
if ((mask & 0xffff) == 0xffff) need_mask = false;
} else {
if (mask == 0xffffffff) need_mask = false;
}
}
if (fall_through_on_failure) {
if (need_mask) {
assembler->CheckCharacterAfterAnd(value, mask, on_possible_success);
} else {
assembler->CheckCharacter(value, on_possible_success);
}
} else {
if (need_mask) {
assembler->CheckNotCharacterAfterAnd(value, mask, trace->backtrack());
} else {
assembler->CheckNotCharacter(value, trace->backtrack());
}
}
return true;
}
// Here is the meat of GetQuickCheckDetails (see also the comment on the
// super-class in the .h file).
//
// We iterate along the text object, building up for each character a
// mask and value that can be used to test for a quick failure to match.
// The masks and values for the positions will be combined into a single
// machine word for the current character width in order to be used in
// generating a quick check.
void TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
intptr_t characters_filled_in,
bool not_at_start) {
#if defined(__GNUC__) && defined(__BYTE_ORDER__)
// TODO(zerny): Make the combination code byte-order independent.
ASSERT(details->characters() == 1 ||
(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__));
#endif
// Do not collect any quick check details if the text node reads backward,
// since it reads in the opposite direction than we use for quick checks.
if (read_backward()) return;
ASSERT(characters_filled_in < details->characters());
intptr_t characters = details->characters();
int32_t char_mask;
if (compiler->one_byte()) {
char_mask = Symbols::kMaxOneCharCodeSymbol;
} else {
char_mask = Utf16::kMaxCodeUnit;
}
for (intptr_t k = 0; k < elms_->length(); k++) {
TextElement elm = elms_->At(k);
if (elm.text_type() == TextElement::ATOM) {
ZoneGrowableArray<uint16_t>* quarks = elm.atom()->data();
for (intptr_t i = 0; i < characters && i < quarks->length(); i++) {
QuickCheckDetails::Position* pos =
details->positions(characters_filled_in);
uint16_t c = quarks->At(i);
if (c > char_mask) {
// If we expect a non-Latin1 character from an one-byte string,
// there is no way we can match. Not even case independent
// matching can turn an Latin1 character into non-Latin1 or
// vice versa.
// TODO(dcarney): issue 3550. Verify that this works as expected.
// For example, \u0178 is uppercase of \u00ff (y-umlaut).
details->set_cannot_match();
pos->determines_perfectly = false;
return;
}
if (elm.atom()->ignore_case()) {
int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
intptr_t length =
GetCaseIndependentLetters(c, compiler->one_byte(), chars);
ASSERT(length != 0); // Can only happen if c > char_mask (see above).
if (length == 1) {
// This letter has no case equivalents, so it's nice and simple
// and the mask-compare will determine definitely whether we have
// a match at this character position.
pos->mask = char_mask;
pos->value = c;
pos->determines_perfectly = true;
} else {
uint32_t common_bits = char_mask;
uint32_t bits = chars[0];
for (intptr_t j = 1; j < length; j++) {
uint32_t differing_bits = ((chars[j] & common_bits) ^ bits);
common_bits ^= differing_bits;
bits &= common_bits;
}
// If length is 2 and common bits has only one zero in it then
// our mask and compare instruction will determine definitely
// whether we have a match at this character position. Otherwise
// it can only be an approximate check.
uint32_t one_zero = (common_bits | ~char_mask);
if (length == 2 && ((~one_zero) & ((~one_zero) - 1)) == 0) {
pos->determines_perfectly = true;
}
pos->mask = common_bits;
pos->value = bits;
}
} else {
// Don't ignore case. Nice simple case where the mask-compare will
// determine definitely whether we have a match at this character
// position.
pos->mask = char_mask;
pos->value = c;
pos->determines_perfectly = true;
}
characters_filled_in++;
ASSERT(characters_filled_in <= details->characters());
if (characters_filled_in == details->characters()) {
return;
}
}
} else {
QuickCheckDetails::Position* pos =
details->positions(characters_filled_in);
RegExpCharacterClass* tree = elm.char_class();
ZoneGrowableArray<CharacterRange>* ranges = tree->ranges();
ASSERT(!ranges->is_empty());
if (!CharacterRange::IsCanonical(ranges)) {
CharacterRange::Canonicalize(ranges);
}
if (tree->is_negated()) {
// A quick check uses multi-character mask and compare. There is no
// useful way to incorporate a negative char class into this scheme
// so we just conservatively create a mask and value that will always
// succeed.
pos->mask = 0;
pos->value = 0;
} else {
intptr_t first_range = 0;
while (ranges->At(first_range).from() > char_mask) {
first_range++;
if (first_range == ranges->length()) {
details->set_cannot_match();
pos->determines_perfectly = false;
return;
}
}
CharacterRange range = ranges->At(first_range);
uint16_t from = range.from();
uint16_t to = range.to();
if (to > char_mask) {
to = char_mask;
}
uint32_t differing_bits = (from ^ to);
// A mask and compare is only perfect if the differing bits form a
// number like 00011111 with one single block of trailing 1s.
if ((differing_bits & (differing_bits + 1)) == 0 &&
from + differing_bits == to) {
pos->determines_perfectly = true;
}
uint32_t common_bits = ~SmearBitsRight(differing_bits);
uint32_t bits = (from & common_bits);
for (intptr_t i = first_range + 1; i < ranges->length(); i++) {
CharacterRange range = ranges->At(i);
uint16_t from = range.from();
uint16_t to = range.to();
if (from > char_mask) continue;
if (to > char_mask) to = char_mask;
// Here we are combining more ranges into the mask and compare
// value. With each new range the mask becomes more sparse and
// so the chances of a false positive rise. A character class
// with multiple ranges is assumed never to be equivalent to a
// mask and compare operation.
pos->determines_perfectly = false;
uint32_t new_common_bits = (from ^ to);
new_common_bits = ~SmearBitsRight(new_common_bits);
common_bits &= new_common_bits;
bits &= new_common_bits;
uint32_t differing_bits = (from & common_bits) ^ bits;
common_bits ^= differing_bits;
bits &= common_bits;
}
pos->mask = common_bits;
pos->value = bits;
}
characters_filled_in++;
ASSERT(characters_filled_in <= details->characters());
if (characters_filled_in == details->characters()) {
return;
}
}
}
ASSERT(characters_filled_in != details->characters());
if (!details->cannot_match()) {
on_success()->GetQuickCheckDetails(details, compiler, characters_filled_in,
true);
}
}
void QuickCheckDetails::Clear() {
for (int i = 0; i < characters_; i++) {
positions_[i].mask = 0;
positions_[i].value = 0;
positions_[i].determines_perfectly = false;
}
characters_ = 0;
}
void QuickCheckDetails::Advance(intptr_t by, bool one_byte) {
if (by >= characters_ || by < 0) {
// check that by < 0 => characters_ == 0
ASSERT(by >= 0 || characters_ == 0);
Clear();
return;
}
for (intptr_t i = 0; i < characters_ - by; i++) {
positions_[i] = positions_[by + i];
}
for (intptr_t i = characters_ - by; i < characters_; i++) {
positions_[i].mask = 0;
positions_[i].value = 0;
positions_[i].determines_perfectly = false;
}
characters_ -= by;
// We could change mask_ and value_ here but we would never advance unless
// they had already been used in a check and they won't be used again because
// it would gain us nothing. So there's no point.
}
void QuickCheckDetails::Merge(QuickCheckDetails* other, intptr_t from_index) {
ASSERT(characters_ == other->characters_);
if (other->cannot_match_) {
return;
}
if (cannot_match_) {
*this = *other;
return;
}
for (intptr_t i = from_index; i < characters_; i++) {
QuickCheckDetails::Position* pos = positions(i);
QuickCheckDetails::Position* other_pos = other->positions(i);
if (pos->mask != other_pos->mask || pos->value != other_pos->value ||
!other_pos->determines_perfectly) {
// Our mask-compare operation will be approximate unless we have the
// exact same operation on both sides of the alternation.
pos->determines_perfectly = false;
}
pos->mask &= other_pos->mask;
pos->value &= pos->mask;
other_pos->value &= pos->mask;
uint16_t differing_bits = (pos->value ^ other_pos->value);
pos->mask &= ~differing_bits;
pos->value &= pos->mask;
}
}
class VisitMarker : public ValueObject {
public:
explicit VisitMarker(NodeInfo* info) : info_(info) {
ASSERT(!info->visited);
info->visited = true;
}
~VisitMarker() { info_->visited = false; }
private:
NodeInfo* info_;
};
RegExpNode* SeqRegExpNode::FilterOneByte(intptr_t depth) {
if (info()->replacement_calculated) return replacement();
if (depth < 0) return this;
ASSERT(!info()->visited);
VisitMarker marker(info());
return FilterSuccessor(depth - 1);
}
RegExpNode* SeqRegExpNode::FilterSuccessor(intptr_t depth) {
RegExpNode* next = on_success_->FilterOneByte(depth - 1);
if (next == nullptr) return set_replacement(nullptr);
on_success_ = next;
return set_replacement(this);
}
// We need to check for the following characters: 0x39c 0x3bc 0x178.
static inline bool RangeContainsLatin1Equivalents(CharacterRange range) {
// TODO(dcarney): this could be a lot more efficient.
return range.Contains(0x39c) || range.Contains(0x3bc) ||
range.Contains(0x178);
}
static bool RangesContainLatin1Equivalents(
ZoneGrowableArray<CharacterRange>* ranges) {
for (intptr_t i = 0; i < ranges->length(); i++) {
// TODO(dcarney): this could be a lot more efficient.
if (RangeContainsLatin1Equivalents(ranges->At(i))) return true;
}
return false;
}
static uint16_t ConvertNonLatin1ToLatin1(uint16_t c) {
ASSERT(c > Symbols::kMaxOneCharCodeSymbol);
switch (c) {
// This are equivalent characters in unicode.
case 0x39c:
case 0x3bc:
return 0xb5;
// This is an uppercase of a Latin-1 character
// outside of Latin-1.
case 0x178:
return 0xff;
}
return 0;
}
RegExpNode* TextNode::FilterOneByte(intptr_t depth) {
if (info()->replacement_calculated) return replacement();
if (depth < 0) return this;
ASSERT(!info()->visited);
VisitMarker marker(info());
intptr_t element_count = elms_->length();
for (intptr_t i = 0; i < element_count; i++) {
TextElement elm = elms_->At(i);
if (elm.text_type() == TextElement::ATOM) {
ZoneGrowableArray<uint16_t>* quarks = elm.atom()->data();
for (intptr_t j = 0; j < quarks->length(); j++) {
uint16_t c = quarks->At(j);
if (c <= Symbols::kMaxOneCharCodeSymbol) continue;
if (!elm.atom()->ignore_case()) return set_replacement(nullptr);
// Here, we need to check for characters whose upper and lower cases
// are outside the Latin-1 range.
uint16_t converted = ConvertNonLatin1ToLatin1(c);
// Character is outside Latin-1 completely
if (converted == 0) return set_replacement(nullptr);
// Convert quark to Latin-1 in place.
(*quarks)[0] = converted;
}
} else {
ASSERT(elm.text_type() == TextElement::CHAR_CLASS);
RegExpCharacterClass* cc = elm.char_class();
ZoneGrowableArray<CharacterRange>* ranges = cc->ranges();
if (!CharacterRange::IsCanonical(ranges)) {
CharacterRange::Canonicalize(ranges);
}
// Now they are in order so we only need to look at the first.
intptr_t range_count = ranges->length();
if (cc->is_negated()) {
if (range_count != 0 && ranges->At(0).from() == 0 &&
ranges->At(0).to() >= Symbols::kMaxOneCharCodeSymbol) {
// This will be handled in a later filter.
if (cc->flags().IgnoreCase() &&
RangesContainLatin1Equivalents(ranges)) {
continue;
}
return set_replacement(nullptr);
}
} else {
if (range_count == 0 ||
ranges->At(0).from() > Symbols::kMaxOneCharCodeSymbol) {
// This will be handled in a later filter.
if (cc->flags().IgnoreCase() &&
RangesContainLatin1Equivalents(ranges))
continue;
return set_replacement(nullptr);
}
}
}
}
return FilterSuccessor(depth - 1);
}
RegExpNode* LoopChoiceNode::FilterOneByte(intptr_t depth) {
if (info()->replacement_calculated) return replacement();
if (depth < 0) return this;
if (info()->visited) return this;
{
VisitMarker marker(info());
RegExpNode* continue_replacement = continue_node_->FilterOneByte(depth - 1);
// If we can't continue after the loop then there is no sense in doing the
// loop.
if (continue_replacement == nullptr) return set_replacement(nullptr);
}
return ChoiceNode::FilterOneByte(depth - 1);
}
RegExpNode* ChoiceNode::FilterOneByte(intptr_t depth) {
if (info()->replacement_calculated) return replacement();
if (depth < 0) return this;
if (info()->visited) return this;
VisitMarker marker(info());
intptr_t choice_count = alternatives_->length();
for (intptr_t i = 0; i < choice_count; i++) {
GuardedAlternative alternative = alternatives_->At(i);
if (alternative.guards() != nullptr &&
alternative.guards()->length() != 0) {
set_replacement(this);
return this;
}
}
intptr_t surviving = 0;
RegExpNode* survivor = nullptr;
for (intptr_t i = 0; i < choice_count; i++) {
GuardedAlternative alternative = alternatives_->At(i);
RegExpNode* replacement = alternative.node()->FilterOneByte(depth - 1);
ASSERT(replacement != this); // No missing EMPTY_MATCH_CHECK.
if (replacement != nullptr) {
(*alternatives_)[i].set_node(replacement);
surviving++;
survivor = replacement;
}
}
if (surviving < 2) return set_replacement(survivor);
set_replacement(this);
if (surviving == choice_count) {
return this;
}
// Only some of the nodes survived the filtering. We need to rebuild the
// alternatives list.
ZoneGrowableArray<GuardedAlternative>* new_alternatives =
new (Z) ZoneGrowableArray<GuardedAlternative>(surviving);
for (intptr_t i = 0; i < choice_count; i++) {
RegExpNode* replacement =
(*alternatives_)[i].node()->FilterOneByte(depth - 1);
if (replacement != nullptr) {
(*alternatives_)[i].set_node(replacement);
new_alternatives->Add((*alternatives_)[i]);
}
}
alternatives_ = new_alternatives;
return this;
}
RegExpNode* NegativeLookaroundChoiceNode::FilterOneByte(intptr_t depth) {
if (info()->replacement_calculated) return replacement();
if (depth < 0) return this;
if (info()->visited) return this;
VisitMarker marker(info());
// Alternative 0 is the negative lookahead, alternative 1 is what comes
// afterwards.
RegExpNode* node = (*alternatives_)[1].node();
RegExpNode* replacement = node->FilterOneByte(depth - 1);
if (replacement == nullptr) return set_replacement(nullptr);
(*alternatives_)[1].set_node(replacement);
RegExpNode* neg_node = (*alternatives_)[0].node();
RegExpNode* neg_replacement = neg_node->FilterOneByte(depth - 1);
// If the negative lookahead is always going to fail then
// we don't need to check it.
if (neg_replacement == nullptr) return set_replacement(replacement);
(*alternatives_)[0].set_node(neg_replacement);
return set_replacement(this);
}
void LoopChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
intptr_t characters_filled_in,
bool not_at_start) {
if (body_can_be_zero_length_ || info()->visited) return;
VisitMarker marker(info());
return ChoiceNode::GetQuickCheckDetails(details, compiler,
characters_filled_in, not_at_start);
}
void LoopChoiceNode::FillInBMInfo(intptr_t offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
if (body_can_be_zero_length_ || budget <= 0) {
bm->SetRest(offset);
SaveBMInfo(bm, not_at_start, offset);
return;
}
ChoiceNode::FillInBMInfo(offset, budget - 1, bm, not_at_start);
SaveBMInfo(bm, not_at_start, offset);
}
void ChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
intptr_t characters_filled_in,
bool not_at_start) {
not_at_start = (not_at_start || not_at_start_);
intptr_t choice_count = alternatives_->length();
ASSERT(choice_count > 0);
(*alternatives_)[0].node()->GetQuickCheckDetails(
details, compiler, characters_filled_in, not_at_start);
for (intptr_t i = 1; i < choice_count; i++) {
QuickCheckDetails new_details(details->characters());
RegExpNode* node = (*alternatives_)[i].node();
node->GetQuickCheckDetails(&new_details, compiler, characters_filled_in,
not_at_start);
// Here we merge the quick match details of the two branches.
details->Merge(&new_details, characters_filled_in);
}
}
// Check for [0-9A-Z_a-z].
static void EmitWordCheck(RegExpMacroAssembler* assembler,
BlockLabel* word,
BlockLabel* non_word,
bool fall_through_on_word) {
if (assembler->CheckSpecialCharacterClass(
fall_through_on_word ? 'w' : 'W',
fall_through_on_word ? non_word : word)) {
// Optimized implementation available.
return;
}
assembler->CheckCharacterGT('z', non_word);
assembler->CheckCharacterLT('0', non_word);
assembler->CheckCharacterGT('a' - 1, word);
assembler->CheckCharacterLT('9' + 1, word);
assembler->CheckCharacterLT('A', non_word);
assembler->CheckCharacterLT('Z' + 1, word);
if (fall_through_on_word) {
assembler->CheckNotCharacter('_', non_word);
} else {
assembler->CheckCharacter('_', word);
}
}
// Emit the code to check for a ^ in multiline mode (1-character lookbehind
// that matches newline or the start of input).
static void EmitHat(RegExpCompiler* compiler,
RegExpNode* on_success,
Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
// We will be loading the previous character into the current character
// register.
Trace new_trace(*trace);
new_trace.InvalidateCurrentCharacter();
BlockLabel ok;
if (new_trace.cp_offset() == 0) {
// The start of input counts as a newline in this context, so skip to
// ok if we are at the start.
assembler->CheckAtStart(&ok);
}
// We already checked that we are not at the start of input so it must be
// OK to load the previous character.
assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1,
new_trace.backtrack(), false);
if (!assembler->CheckSpecialCharacterClass('n', new_trace.backtrack())) {
// Newline means \n, \r, 0x2028 or 0x2029.
if (!compiler->one_byte()) {
assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
}
assembler->CheckCharacter('\n', &ok);
assembler->CheckNotCharacter('\r', new_trace.backtrack());
}
assembler->BindBlock(&ok);
on_success->Emit(compiler, &new_trace);
}
// Emit the code to handle \b and \B (word-boundary or non-word-boundary).
void AssertionNode::EmitBoundaryCheck(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
Trace::TriBool next_is_word_character = Trace::UNKNOWN;
bool not_at_start = (trace->at_start() == Trace::FALSE_VALUE);
BoyerMooreLookahead* lookahead = bm_info(not_at_start);
if (lookahead == nullptr) {
intptr_t eats_at_least =
Utils::Minimum(kMaxLookaheadForBoyerMoore,
EatsAtLeast(kMaxLookaheadForBoyerMoore, kRecursionBudget,
not_at_start));
if (eats_at_least >= 1) {
BoyerMooreLookahead* bm =
new (Z) BoyerMooreLookahead(eats_at_least, compiler, Z);
FillInBMInfo(0, kRecursionBudget, bm, not_at_start);
if (bm->at(0)->is_non_word()) next_is_word_character = Trace::FALSE_VALUE;
if (bm->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE;
}
} else {
if (lookahead->at(0)->is_non_word())
next_is_word_character = Trace::FALSE_VALUE;
if (lookahead->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE;
}
bool at_boundary = (assertion_type_ == AssertionNode::AT_BOUNDARY);
if (next_is_word_character == Trace::UNKNOWN) {
BlockLabel before_non_word;
BlockLabel before_word;
if (trace->characters_preloaded() != 1) {
assembler->LoadCurrentCharacter(trace->cp_offset(), &before_non_word);
}
// Fall through on non-word.
EmitWordCheck(assembler, &before_word, &before_non_word, false);
// Next character is not a word character.
assembler->BindBlock(&before_non_word);
BlockLabel ok;
// Backtrack on \B (non-boundary check) if previous is a word,
// since we know next *is not* a word and this would be a boundary.
BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
if (!assembler->IsClosed()) {
assembler->GoTo(&ok);
}
assembler->BindBlock(&before_word);
BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
assembler->BindBlock(&ok);
} else if (next_is_word_character == Trace::TRUE_VALUE) {
BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
} else {
ASSERT(next_is_word_character == Trace::FALSE_VALUE);
BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
}
}
void AssertionNode::BacktrackIfPrevious(
RegExpCompiler* compiler,
Trace* trace,
AssertionNode::IfPrevious backtrack_if_previous) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
Trace new_trace(*trace);
new_trace.InvalidateCurrentCharacter();
BlockLabel fall_through, dummy;
BlockLabel* non_word = backtrack_if_previous == kIsNonWord
? new_trace.backtrack()
: &fall_through;
BlockLabel* word = backtrack_if_previous == kIsNonWord
? &fall_through
: new_trace.backtrack();
if (new_trace.cp_offset() == 0) {
// The start of input counts as a non-word character, so the question is
// decided if we are at the start.
assembler->CheckAtStart(non_word);
}
// We already checked that we are not at the start of input so it must be
// OK to load the previous character.
assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, &dummy, false);
EmitWordCheck(assembler, word, non_word, backtrack_if_previous == kIsNonWord);
assembler->BindBlock(&fall_through);
on_success()->Emit(compiler, &new_trace);
}
void AssertionNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
intptr_t filled_in,
bool not_at_start) {
if (assertion_type_ == AT_START && not_at_start) {
details->set_cannot_match();
return;
}
return on_success()->GetQuickCheckDetails(details, compiler, filled_in,
not_at_start);
}
void AssertionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
switch (assertion_type_) {
case AT_END: {
BlockLabel ok;
assembler->CheckPosition(trace->cp_offset(), &ok);
assembler->GoTo(trace->backtrack());
assembler->BindBlock(&ok);
break;
}
case AT_START: {
if (trace->at_start() == Trace::FALSE_VALUE) {
assembler->GoTo(trace->backtrack());
return;
}
if (trace->at_start() == Trace::UNKNOWN) {
assembler->CheckNotAtStart(trace->cp_offset(), trace->backtrack());
Trace at_start_trace = *trace;
at_start_trace.set_at_start(Trace::TRUE_VALUE);
on_success()->Emit(compiler, &at_start_trace);
return;
}
} break;
case AFTER_NEWLINE:
EmitHat(compiler, on_success(), trace);
return;
case AT_BOUNDARY:
case AT_NON_BOUNDARY: {
EmitBoundaryCheck(compiler, trace);
return;
}
}
on_success()->Emit(compiler, trace);
}
static bool DeterminedAlready(QuickCheckDetails* quick_check, intptr_t offset) {
if (quick_check == nullptr) return false;
if (offset >= quick_check->characters()) return false;
return quick_check->positions(offset)->determines_perfectly;
}
static void UpdateBoundsCheck(intptr_t index, intptr_t* checked_up_to) {
if (index > *checked_up_to) {
*checked_up_to = index;
}
}
// We call this repeatedly to generate code for each pass over the text node.
// The passes are in increasing order of difficulty because we hope one
// of the first passes will fail in which case we are saved the work of the
// later passes. for example for the case independent regexp /%[asdfghjkl]a/
// we will check the '%' in the first pass, the case independent 'a' in the
// second pass and the character class in the last pass.
//
// The passes are done from right to left, so for example to test for /bar/
// we will first test for an 'r' with offset 2, then an 'a' with offset 1
// and then a 'b' with offset 0. This means we can avoid the end-of-input
// bounds check most of the time. In the example we only need to check for
// end-of-input when loading the putative 'r'.
//
// A slight complication involves the fact that the first character may already
// be fetched into a register by the previous node. In this case we want to
// do the test for that character first. We do this in separate passes. The
// 'preloaded' argument indicates that we are doing such a 'pass'. If such a
// pass has been performed then subsequent passes will have true in
// first_element_checked to indicate that character does not need to be
// checked again.
//
// In addition to all this we are passed a Trace, which can
// contain an AlternativeGeneration object. In this AlternativeGeneration
// object we can see details of any quick check that was already passed in
// order to get to the code we are now generating. The quick check can involve
// loading characters, which means we do not need to recheck the bounds
// up to the limit the quick check already checked. In addition the quick
// check can have involved a mask and compare operation which may simplify
// or obviate the need for further checks at some character positions.
void TextNode::TextEmitPass(RegExpCompiler* compiler,
TextEmitPassType pass,
bool preloaded,
Trace* trace,
bool first_element_checked,
intptr_t* checked_up_to) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
bool one_byte = compiler->one_byte();
BlockLabel* backtrack = trace->backtrack();
QuickCheckDetails* quick_check = trace->quick_check_performed();
intptr_t element_count = elms_->length();
intptr_t backward_offset = read_backward() ? -Length() : 0;
for (intptr_t i = preloaded ? 0 : element_count - 1; i >= 0; i--) {
TextElement elm = elms_->At(i);
intptr_t cp_offset = trace->cp_offset() + elm.cp_offset() + backward_offset;
if (elm.text_type() == TextElement::ATOM) {
ZoneGrowableArray<uint16_t>* quarks = elm.atom()->data();
for (intptr_t j = preloaded ? 0 : quarks->length() - 1; j >= 0; j--) {
if (SkipPass(pass, elm.atom()->ignore_case())) continue;
if (first_element_checked && i == 0 && j == 0) continue;
if (DeterminedAlready(quick_check, elm.cp_offset() + j)) continue;
EmitCharacterFunction* emit_function = nullptr;
uint16_t quark = quarks->At(j);
if (elm.atom()->ignore_case()) {
// Everywhere else we assume that a non-Latin-1 character cannot match
// a Latin-1 character. Avoid the cases where this is assumption is
// invalid by using the Latin1 equivalent instead.
quark = Latin1::TryConvertToLatin1(quark);
}
switch (pass) {
case NON_LATIN1_MATCH:
ASSERT(one_byte);
if (quark > Symbols::kMaxOneCharCodeSymbol) {
assembler->GoTo(backtrack);
return;
}
break;
case NON_LETTER_CHARACTER_MATCH:
emit_function = &EmitAtomNonLetter;
break;
case SIMPLE_CHARACTER_MATCH:
emit_function = &EmitSimpleCharacter;
break;
case CASE_CHARACTER_MATCH:
emit_function = &EmitAtomLetter;
break;
default:
break;
}
if (emit_function != nullptr) {
const bool bounds_check =
*checked_up_to < (cp_offset + j) || read_backward();
bool bound_checked =
emit_function(Z, compiler, quarks->At(j), backtrack,
cp_offset + j, bounds_check, preloaded);
if (bound_checked) UpdateBoundsCheck(cp_offset + j, checked_up_to);
}
}
} else {
ASSERT(elm.text_type() == TextElement::CHAR_CLASS);
if (pass == CHARACTER_CLASS_MATCH) {
if (first_element_checked && i == 0) continue;
if (DeterminedAlready(quick_check, elm.cp_offset())) continue;
RegExpCharacterClass* cc = elm.char_class();
bool bounds_check = *checked_up_to < cp_offset || read_backward();
EmitCharClass(assembler, cc, one_byte, backtrack, cp_offset,
bounds_check, preloaded, Z);
UpdateBoundsCheck(cp_offset, checked_up_to);
}
}
}
}
intptr_t TextNode::Length() {
TextElement elm = elms_->Last();
ASSERT(elm.cp_offset() >= 0);
return elm.cp_offset() + elm.length();
}
bool TextNode::SkipPass(intptr_t intptr_t_pass, bool ignore_case) {
TextEmitPassType pass = static_cast<TextEmitPassType>(intptr_t_pass);
if (ignore_case) {
return pass == SIMPLE_CHARACTER_MATCH;
} else {
return pass == NON_LETTER_CHARACTER_MATCH || pass == CASE_CHARACTER_MATCH;
}
}
TextNode* TextNode::CreateForCharacterRanges(
ZoneGrowableArray<CharacterRange>* ranges,
bool read_backward,
RegExpNode* on_success,
RegExpFlags flags) {
ASSERT(ranges != nullptr);
ZoneGrowableArray<TextElement>* elms = new ZoneGrowableArray<TextElement>(1);
elms->Add(TextElement::CharClass(new RegExpCharacterClass(ranges, flags)));
return new TextNode(elms, read_backward, on_success);
}
TextNode* TextNode::CreateForSurrogatePair(CharacterRange lead,
CharacterRange trail,
bool read_backward,
RegExpNode* on_success,
RegExpFlags flags) {
auto lead_ranges = CharacterRange::List(on_success->zone(), lead);
auto trail_ranges = CharacterRange::List(on_success->zone(), trail);
auto elms = new ZoneGrowableArray<TextElement>(2);
elms->Add(
TextElement::CharClass(new RegExpCharacterClass(lead_ranges, flags)));
elms->Add(
TextElement::CharClass(new RegExpCharacterClass(trail_ranges, flags)));
return new TextNode(elms, read_backward, on_success);
}
// This generates the code to match a text node. A text node can contain
// straight character sequences (possibly to be matched in a case-independent
// way) and character classes. For efficiency we do not do this in a single
// pass from left to right. Instead we pass over the text node several times,
// emitting code for some character positions every time. See the comment on
// TextEmitPass for details.
void TextNode::Emit(RegExpCompiler* compiler, Trace* trace) {
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
if (trace->cp_offset() + Length() > RegExpMacroAssembler::kMaxCPOffset) {
compiler->SetRegExpTooBig();
return;
}
if (compiler->one_byte()) {
intptr_t dummy = 0;
TextEmitPass(compiler, NON_LATIN1_MATCH, false, trace, false, &dummy);
}
bool first_elt_done = false;
intptr_t bound_checked_to = trace->cp_offset() - 1;
bound_checked_to += trace->bound_checked_up_to();
// If a character is preloaded into the current character register then
// check that now.
if (trace->characters_preloaded() == 1) {
for (intptr_t pass = kFirstRealPass; pass <= kLastPass; pass++) {
TextEmitPass(compiler, static_cast<TextEmitPassType>(pass), true, trace,
false, &bound_checked_to);
}
first_elt_done = true;
}
for (intptr_t pass = kFirstRealPass; pass <= kLastPass; pass++) {
TextEmitPass(compiler, static_cast<TextEmitPassType>(pass), false, trace,
first_elt_done, &bound_checked_to);
}
Trace successor_trace(*trace);
// If we advance backward, we may end up at the start.
successor_trace.AdvanceCurrentPositionInTrace(
read_backward() ? -Length() : Length(), compiler);
successor_trace.set_at_start(read_backward() ? Trace::UNKNOWN
: Trace::FALSE_VALUE);
RecursionCheck rc(compiler);
on_success()->Emit(compiler, &successor_trace);
}
void Trace::InvalidateCurrentCharacter() {
characters_preloaded_ = 0;
}
void Trace::AdvanceCurrentPositionInTrace(intptr_t by,
RegExpCompiler* compiler) {
// We don't have an instruction for shifting the current character register
// down or for using a shifted value for anything so lets just forget that
// we preloaded any characters into it.
characters_preloaded_ = 0;
// Adjust the offsets of the quick check performed information. This
// information is used to find out what we already determined about the
// characters by means of mask and compare.
quick_check_performed_.Advance(by, compiler->one_byte());
cp_offset_ += by;
if (cp_offset_ > RegExpMacroAssembler::kMaxCPOffset) {
compiler->SetRegExpTooBig();
cp_offset_ = 0;
}
bound_checked_up_to_ =
Utils::Maximum(static_cast<intptr_t>(0), bound_checked_up_to_ - by);
}
void TextNode::MakeCaseIndependent(bool is_one_byte) {
intptr_t element_count = elms_->length();
for (intptr_t i = 0; i < element_count; i++) {
TextElement elm = elms_->At(i);
if (elm.text_type() == TextElement::CHAR_CLASS) {
RegExpCharacterClass* cc = elm.char_class();
bool case_equivalents_already_added =
cc->flags().NeedsUnicodeCaseEquivalents();
if (cc->flags().IgnoreCase() && !case_equivalents_already_added) {
// None of the standard character classes is different in the case
// independent case and it slows us down if we don't know that.
if (cc->is_standard()) continue;
CharacterRange::AddCaseEquivalents(cc->ranges(), is_one_byte, Z);
}
}
}
}
intptr_t TextNode::GreedyLoopTextLength() {
TextElement elm = elms_->At(elms_->length() - 1);
return elm.cp_offset() + elm.length();
}
RegExpNode* TextNode::GetSuccessorOfOmnivorousTextNode(
RegExpCompiler* compiler) {
if (read_backward()) return nullptr;
if (elms_->length() != 1) return nullptr;
TextElement elm = elms_->At(0);
if (elm.text_type() != TextElement::CHAR_CLASS) return nullptr;
RegExpCharacterClass* node = elm.char_class();
ZoneGrowableArray<CharacterRange>* ranges = node->ranges();
if (!CharacterRange::IsCanonical(ranges)) {
CharacterRange::Canonicalize(ranges);
}
if (node->is_negated()) {
return ranges->length() == 0 ? on_success() : nullptr;
}
if (ranges->length() != 1) return nullptr;
uint32_t max_char;
if (compiler->one_byte()) {
max_char = Symbols::kMaxOneCharCodeSymbol;
} else {
max_char = Utf16::kMaxCodeUnit;
}
return ranges->At(0).IsEverything(max_char) ? on_success() : nullptr;
}
// Finds the fixed match length of a sequence of nodes that goes from
// this alternative and back to this choice node. If there are variable
// length nodes or other complications in the way then return a sentinel
// value indicating that a greedy loop cannot be constructed.
intptr_t ChoiceNode::GreedyLoopTextLengthForAlternative(
const GuardedAlternative* alternative) {
intptr_t length = 0;
RegExpNode* node = alternative->node();
// Later we will generate code for all these text nodes using recursion
// so we have to limit the max number.
intptr_t recursion_depth = 0;
while (node != this) {
if (recursion_depth++ > RegExpCompiler::kMaxRecursion) {
return kNodeIsTooComplexForGreedyLoops;
}
intptr_t node_length = node->GreedyLoopTextLength();
if (node_length == kNodeIsTooComplexForGreedyLoops) {
return kNodeIsTooComplexForGreedyLoops;
}
length += node_length;
SeqRegExpNode* seq_node = static_cast<SeqRegExpNode*>(node);
node = seq_node->on_success();
}
return read_backward() ? -length : length;
}
void LoopChoiceNode::AddLoopAlternative(GuardedAlternative alt) {
ASSERT(loop_node_ == nullptr);
AddAlternative(alt);
loop_node_ = alt.node();
}
void LoopChoiceNode::AddContinueAlternative(GuardedAlternative alt) {
ASSERT(continue_node_ == nullptr);
AddAlternative(alt);
continue_node_ = alt.node();
}
void LoopChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
if (trace->stop_node() == this) {
// Back edge of greedy optimized loop node graph.
intptr_t text_length =
GreedyLoopTextLengthForAlternative(&alternatives_->At(0));
ASSERT(text_length != kNodeIsTooComplexForGreedyLoops);
// Update the counter-based backtracking info on the stack. This is an
// optimization for greedy loops (see below).
ASSERT(trace->cp_offset() == text_length);
macro_assembler->AdvanceCurrentPosition(text_length);
macro_assembler->GoTo(trace->loop_label());
return;
}
ASSERT(trace->stop_node() == nullptr);
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
ChoiceNode::Emit(compiler, trace);
}
intptr_t ChoiceNode::CalculatePreloadCharacters(RegExpCompiler* compiler,
intptr_t eats_at_least) {
intptr_t preload_characters =
Utils::Minimum(static_cast<intptr_t>(4), eats_at_least);
if (compiler->one_byte()) {
#if !defined(DART_COMPRESSED_POINTERS) && !defined(TARGET_ARCH_RISCV32)
if (preload_characters > 4) preload_characters = 4;
// We can't preload 3 characters because there is no machine instruction
// to do that. We can't just load 4 because we could be reading
// beyond the end of the string, which could cause a memory fault.
if (preload_characters == 3) preload_characters = 2;
#else
// Ensure LoadCodeUnitsInstr can always produce a Smi. See
// https://github.com/dart-lang/sdk/issues/29951
if (preload_characters > 2) preload_characters = 2;
#endif
} else {
#if !defined(DART_COMPRESSED_POINTERS) && !defined(TARGET_ARCH_RISCV32)
if (preload_characters > 2) preload_characters = 2;
#else
// Ensure LoadCodeUnitsInstr can always produce a Smi. See
// https://github.com/dart-lang/sdk/issues/29951
if (preload_characters > 1) preload_characters = 1;
#endif
}
if (!compiler->macro_assembler()->CanReadUnaligned()) {
if (preload_characters > 1) preload_characters = 1;
}
return preload_characters;
}
// This structure is used when generating the alternatives in a choice node. It
// records the way the alternative is being code generated.
struct AlternativeGeneration {
AlternativeGeneration()
: possible_success(),
expects_preload(false),
after(),
quick_check_details() {}
BlockLabel possible_success;
bool expects_preload;
BlockLabel after;
QuickCheckDetails quick_check_details;
};
// Creates a list of AlternativeGenerations. If the list has a reasonable
// size then it is on the stack, otherwise the excess is on the heap.
class AlternativeGenerationList {
public:
explicit AlternativeGenerationList(intptr_t count) : count_(count) {
ASSERT(count >= 0);
if (count > kAFew) {
excess_alt_gens_.reset(new AlternativeGeneration[count - kAFew]);
}
}
AlternativeGeneration* at(intptr_t i) {
ASSERT(0 <= i);
ASSERT(i < count_);
if (i < kAFew) {
return &a_few_alt_gens_[i];
}
return &excess_alt_gens_[i - kAFew];
}
private:
static constexpr intptr_t kAFew = 10;
intptr_t count_;
AlternativeGeneration a_few_alt_gens_[kAFew];
std::unique_ptr<AlternativeGeneration[]> excess_alt_gens_;
DISALLOW_ALLOCATION();
DISALLOW_COPY_AND_ASSIGN(AlternativeGenerationList);
};
static constexpr int32_t kRangeEndMarker = Utf::kMaxCodePoint + 1;
// The '2' variant is inclusive from and exclusive to.
// This covers \s as defined in ECMA-262 5.1, 15.10.2.12,
// which include WhiteSpace (7.2) or LineTerminator (7.3) values.
// 0x180E has been removed from Unicode's Zs category and thus
// from ECMAScript's WhiteSpace category as of Unicode 6.3.
static constexpr int32_t kSpaceRanges[] = {
'\t', '\r' + 1, ' ', ' ' + 1, 0x00A0, 0x00A1, 0x1680,
0x1681, 0x2000, 0x200B, 0x2028, 0x202A, 0x202F, 0x2030,
0x205F, 0x2060, 0x3000, 0x3001, 0xFEFF, 0xFF00, kRangeEndMarker};
static constexpr intptr_t kSpaceRangeCount = ARRAY_SIZE(kSpaceRanges);
static constexpr int32_t kWordRanges[] = {
'0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, kRangeEndMarker};
static constexpr intptr_t kWordRangeCount = ARRAY_SIZE(kWordRanges);
static constexpr int32_t kDigitRanges[] = {'0', '9' + 1, kRangeEndMarker};
static constexpr intptr_t kDigitRangeCount = ARRAY_SIZE(kDigitRanges);
static constexpr int32_t kSurrogateRanges[] = {0xd800, 0xe000, kRangeEndMarker};
static constexpr intptr_t kSurrogateRangeCount = ARRAY_SIZE(kSurrogateRanges);
static constexpr int32_t kLineTerminatorRanges[] = {
0x000A, 0x000B, 0x000D, 0x000E, 0x2028, 0x202A, kRangeEndMarker};
static constexpr intptr_t kLineTerminatorRangeCount =
ARRAY_SIZE(kLineTerminatorRanges);
void BoyerMoorePositionInfo::Set(intptr_t character) {
SetInterval(Interval(character, character));
}
void BoyerMoorePositionInfo::SetInterval(const Interval& interval) {
s_ = AddRange(s_, kSpaceRanges, kSpaceRangeCount, interval);
w_ = AddRange(w_, kWordRanges, kWordRangeCount, interval);
d_ = AddRange(d_, kDigitRanges, kDigitRangeCount, interval);
surrogate_ =
AddRange(surrogate_, kSurrogateRanges, kSurrogateRangeCount, interval);
if (interval.to() - interval.from() >= kMapSize - 1) {
if (map_count_ != kMapSize) {
map_count_ = kMapSize;
for (intptr_t i = 0; i < kMapSize; i++)
(*map_)[i] = true;
}
return;
}
for (intptr_t i = interval.from(); i <= interval.to(); i++) {
intptr_t mod_character = (i & kMask);
if (!map_->At(mod_character)) {
map_count_++;
(*map_)[mod_character] = true;
}
if (map_count_ == kMapSize) return;
}
}
void BoyerMoorePositionInfo::SetAll() {
s_ = w_ = d_ = kLatticeUnknown;
if (map_count_ != kMapSize) {
map_count_ = kMapSize;
for (intptr_t i = 0; i < kMapSize; i++)
(*map_)[i] = true;
}
}
BoyerMooreLookahead::BoyerMooreLookahead(intptr_t length,
RegExpCompiler* compiler,
Zone* zone)
: length_(length), compiler_(compiler) {
if (compiler->one_byte()) {
max_char_ = Symbols::kMaxOneCharCodeSymbol;
} else {
max_char_ = Utf16::kMaxCodeUnit;
}
bitmaps_ = new (zone) ZoneGrowableArray<BoyerMoorePositionInfo*>(length);
for (intptr_t i = 0; i < length; i++) {
bitmaps_->Add(new (zone) BoyerMoorePositionInfo(zone));
}
}
// Find the longest range of lookahead that has the fewest number of different
// characters that can occur at a given position. Since we are optimizing two
// different parameters at once this is a tradeoff.
bool BoyerMooreLookahead::FindWorthwhileInterval(intptr_t* from, intptr_t* to) {
intptr_t biggest_points = 0;
// If more than 32 characters out of 128 can occur it is unlikely that we can
// be lucky enough to step forwards much of the time.
const intptr_t kMaxMax = 32;
for (intptr_t max_number_of_chars = 4; max_number_of_chars < kMaxMax;
max_number_of_chars *= 2) {
biggest_points =
FindBestInterval(max_number_of_chars, biggest_points, from, to);
}
if (biggest_points == 0) return false;
return true;
}
// Find the highest-points range between 0 and length_ where the character
// information is not too vague. 'Too vague' means that there are more than
// max_number_of_chars that can occur at this position. Calculates the number
// of points as the product of width-of-the-range and
// probability-of-finding-one-of-the-characters, where the probability is
// calculated using the frequency distribution of the sample subject string.
intptr_t BoyerMooreLookahead::FindBestInterval(intptr_t max_number_of_chars,
intptr_t old_biggest_points,
intptr_t* from,
intptr_t* to) {
intptr_t biggest_points = old_biggest_points;
static constexpr intptr_t kSize = RegExpMacroAssembler::kTableSize;
for (intptr_t i = 0; i < length_;) {
while (i < length_ && Count(i) > max_number_of_chars)
i++;
if (i == length_) break;
intptr_t remembered_from = i;
bool union_map[kSize];
for (intptr_t j = 0; j < kSize; j++)
union_map[j] = false;
while (i < length_ && Count(i) <= max_number_of_chars) {
BoyerMoorePositionInfo* map = bitmaps_->At(i);
for (intptr_t j = 0; j < kSize; j++)
union_map[j] |= map->at(j);
i++;
}
intptr_t frequency = 0;
for (intptr_t j = 0; j < kSize; j++) {
if (union_map[j]) {
// Add 1 to the frequency to give a small per-character boost for
// the cases where our sampling is not good enough and many
// characters have a frequency of zero. This means the frequency
// can theoretically be up to 2*kSize though we treat it mostly as
// a fraction of kSize.
frequency += compiler_->frequency_collator()->Frequency(j) + 1;
}
}
// We use the probability of skipping times the distance we are skipping to
// judge the effectiveness of this. Actually we have a cut-off: By
// dividing by 2 we switch off the skipping if the probability of skipping
// is less than 50%. This is because the multibyte mask-and-compare
// skipping in quickcheck is more likely to do well on this case.
bool in_quickcheck_range =
((i - remembered_from < 4) ||
(compiler_->one_byte() ? remembered_from <= 4 : remembered_from <= 2));
// Called 'probability' but it is only a rough estimate and can actually
// be outside the 0-kSize range.
intptr_t probability =
(in_quickcheck_range ? kSize / 2 : kSize) - frequency;
intptr_t points = (i - remembered_from) * probability;
if (points > biggest_points) {
*from = remembered_from;
*to = i - 1;
biggest_points = points;
}
}
return biggest_points;
}
// Take all the characters that will not prevent a successful match if they
// occur in the subject string in the range between min_lookahead and
// max_lookahead (inclusive) measured from the current position. If the
// character at max_lookahead offset is not one of these characters, then we
// can safely skip forwards by the number of characters in the range.
intptr_t BoyerMooreLookahead::GetSkipTable(
intptr_t min_lookahead,
intptr_t max_lookahead,
const TypedData& boolean_skip_table) {
const intptr_t kSize = RegExpMacroAssembler::kTableSize;
const intptr_t kSkipArrayEntry = 0;
const intptr_t kDontSkipArrayEntry = 1;
for (intptr_t i = 0; i < kSize; i++) {
boolean_skip_table.SetUint8(i, kSkipArrayEntry);
}
intptr_t skip = max_lookahead + 1 - min_lookahead;
for (intptr_t i = max_lookahead; i >= min_lookahead; i--) {
BoyerMoorePositionInfo* map = bitmaps_->At(i);
for (intptr_t j = 0; j < kSize; j++) {
if (map->at(j)) {
boolean_skip_table.SetUint8(j, kDontSkipArrayEntry);
}
}
}
return skip;
}
// See comment above on the implementation of GetSkipTable.
void BoyerMooreLookahead::EmitSkipInstructions(RegExpMacroAssembler* masm) {
const intptr_t kSize = RegExpMacroAssembler::kTableSize;
intptr_t min_lookahead = 0;
intptr_t max_lookahead = 0;
if (!FindWorthwhileInterval(&min_lookahead, &max_lookahead)) return;
bool found_single_character = false;
intptr_t single_character = 0;
for (intptr_t i = max_lookahead; i >= min_lookahead; i--) {
BoyerMoorePositionInfo* map = bitmaps_->At(i);
if (map->map_count() > 1 ||
(found_single_character && map->map_count() != 0)) {
found_single_character = false;
break;
}
for (intptr_t j = 0; j < kSize; j++) {
if (map->at(j)) {
found_single_character = true;
single_character = j;
break;
}
}
}
intptr_t lookahead_width = max_lookahead + 1 - min_lookahead;
if (found_single_character && lookahead_width == 1 && max_lookahead < 3) {
// The mask-compare can probably handle this better.
return;
}
if (found_single_character) {
BlockLabel cont, again;
masm->BindBlock(&again);
masm->LoadCurrentCharacter(max_lookahead, &cont, true);
if (max_char_ > kSize) {
masm->CheckCharacterAfterAnd(single_character,
RegExpMacroAssembler::kTableMask, &cont);
} else {
masm->CheckCharacter(single_character, &cont);
}
masm->AdvanceCurrentPosition(lookahead_width);
masm->GoTo(&again);
masm->BindBlock(&cont);
return;
}
const TypedData& boolean_skip_table = TypedData::ZoneHandle(
compiler_->zone(),
TypedData::New(kTypedDataUint8ArrayCid, kSize, Heap::kOld));
intptr_t skip_distance =
GetSkipTable(min_lookahead, max_lookahead, boolean_skip_table);
ASSERT(skip_distance != 0);
BlockLabel cont, again;
masm->BindBlock(&again);
masm->CheckPreemption(/*is_backtrack=*/false);
masm->LoadCurrentCharacter(max_lookahead, &cont, true);
masm->CheckBitInTable(boolean_skip_table, &cont);
masm->AdvanceCurrentPosition(skip_distance);
masm->GoTo(&again);
masm->BindBlock(&cont);
return;
}
/* Code generation for choice nodes.
*
* We generate quick checks that do a mask and compare to eliminate a
* choice. If the quick check succeeds then it jumps to the continuation to
* do slow checks and check subsequent nodes. If it fails (the common case)
* it falls through to the next choice.
*
* Here is the desired flow graph. Nodes directly below each other imply
* fallthrough. Alternatives 1 and 2 have quick checks. Alternative
* 3 doesn't have a quick check so we have to call the slow check.
* Nodes are marked Qn for quick checks and Sn for slow checks. The entire
* regexp continuation is generated directly after the Sn node, up to the
* next GoTo if we decide to reuse some already generated code. Some
* nodes expect preload_characters to be preloaded into the current
* character register. R nodes do this preloading. Vertices are marked
* F for failures and S for success (possible success in the case of quick
* nodes). L, V, < and > are used as arrow heads.
*
* ----------> R
* |
* V
* Q1 -----> S1
* | S /
* F| /
* | F/
* | /
* | R
* | /
* V L
* Q2 -----> S2
* | S /
* F| /
* | F/
* | /
* | R
* | /
* V L
* S3
* |
* F|
* |
* R
* |
* backtrack V
* <----------Q4
* \ F |
* \ |S
* \ F V
* \-----S4
*
* For greedy loops we push the current position, then generate the code that
* eats the input specially in EmitGreedyLoop. The other choice (the
* continuation) is generated by the normal code in EmitChoices, and steps back
* in the input to the starting position when it fails to match. The loop code
* looks like this (U is the unwind code that steps back in the greedy loop).
*
* _____
* / \
* V |
* ----------> S1 |
* /| |
* / |S |
* F/ \_____/
* /
* |<-----
* | \
* V |S
* Q2 ---> U----->backtrack
* | F /
* S| /
* V F /
* S2--/
*/
GreedyLoopState::GreedyLoopState(bool not_at_start) {
counter_backtrack_trace_.set_backtrack(&label_);
if (not_at_start) counter_backtrack_trace_.set_at_start(Trace::FALSE_VALUE);
}
void ChoiceNode::AssertGuardsMentionRegisters(Trace* trace) {
#ifdef DEBUG
intptr_t choice_count = alternatives_->length();
for (intptr_t i = 0; i < choice_count - 1; i++) {
GuardedAlternative alternative = alternatives_->At(i);
ZoneGrowableArray<Guard*>* guards = alternative.guards();
intptr_t guard_count = (guards == nullptr) ? 0 : guards->length();
for (intptr_t j = 0; j < guard_count; j++) {
ASSERT(!trace->mentions_reg(guards->At(j)->reg()));
}
}
#endif
}
void ChoiceNode::SetUpPreLoad(RegExpCompiler* compiler,
Trace* current_trace,
PreloadState* state) {
if (state->eats_at_least_ == PreloadState::kEatsAtLeastNotYetInitialized) {
// Save some time by looking at most one machine word ahead.
state->eats_at_least_ =
EatsAtLeast(compiler->one_byte() ? 4 : 2, kRecursionBudget,
current_trace->at_start() == Trace::FALSE_VALUE);
}
state->preload_characters_ =
CalculatePreloadCharacters(compiler, state->eats_at_least_);
state->preload_is_current_ =
(current_trace->characters_preloaded() == state->preload_characters_);
state->preload_has_checked_bounds_ = state->preload_is_current_;
}
void ChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
intptr_t choice_count = alternatives_->length();
if (choice_count == 1 && alternatives_->At(0).guards() == nullptr) {
alternatives_->At(0).node()->Emit(compiler, trace);
return;
}
AssertGuardsMentionRegisters(trace);
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
// For loop nodes we already flushed (see LoopChoiceNode::Emit), but for
// other choice nodes we only flush if we are out of code size budget.
if (trace->flush_budget() == 0 && trace->actions() != nullptr) {
trace->Flush(compiler, this);
return;
}
RecursionCheck rc(compiler);
PreloadState preload;
preload.init();
GreedyLoopState greedy_loop_state(not_at_start());
intptr_t text_length =
GreedyLoopTextLengthForAlternative(&alternatives_->At(0));
AlternativeGenerationList alt_gens(choice_count);
if (choice_count > 1 && text_length != kNodeIsTooComplexForGreedyLoops) {
trace = EmitGreedyLoop(compiler, trace, &alt_gens, &preload,
&greedy_loop_state, text_length);
} else {
// TODO(erikcorry): Delete this. We don't need this label, but it makes us
// match the traces produced pre-cleanup.
BlockLabel second_choice;
compiler->macro_assembler()->BindBlock(&second_choice);
preload.eats_at_least_ = EmitOptimizedUnanchoredSearch(compiler, trace);
EmitChoices(compiler, &alt_gens, 0, trace, &preload);
}
// At this point we need to generate slow checks for the alternatives where
// the quick check was inlined. We can recognize these because the associated
// label was bound.
intptr_t new_flush_budget = trace->flush_budget() / choice_count;
for (intptr_t i = 0; i < choice_count; i++) {
AlternativeGeneration* alt_gen = alt_gens.at(i);
Trace new_trace(*trace);
// If there are actions to be flushed we have to limit how many times
// they are flushed. Take the budget of the parent trace and distribute
// it fairly amongst the children.
if (new_trace.actions() != nullptr) {
new_trace.set_flush_budget(new_flush_budget);
}
bool next_expects_preload =
i == choice_count - 1 ? false : alt_gens.at(i + 1)->expects_preload;
EmitOutOfLineContinuation(compiler, &new_trace, alternatives_->At(i),
alt_gen, preload.preload_characters_,
next_expects_preload);
}
}
Trace* ChoiceNode::EmitGreedyLoop(RegExpCompiler* compiler,
Trace* trace,
AlternativeGenerationList* alt_gens,
PreloadState* preload,
GreedyLoopState* greedy_loop_state,
intptr_t text_length) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
// Here we have special handling for greedy loops containing only text nodes
// and other simple nodes. These are handled by pushing the current
// position on the stack and then incrementing the current position each
// time around the switch. On backtrack we decrement the current position
// and check it against the pushed value. This avoids pushing backtrack
// information for each iteration of the loop, which could take up a lot of
// space.
ASSERT(trace->stop_node() == nullptr);
macro_assembler->PushCurrentPosition();
BlockLabel greedy_match_failed;
Trace greedy_match_trace;
if (not_at_start()) greedy_match_trace.set_at_start(Trace::FALSE_VALUE);
greedy_match_trace.set_backtrack(&greedy_match_failed);
BlockLabel loop_label;
macro_assembler->BindBlock(&loop_label);
macro_assembler->CheckPreemption(/*is_backtrack=*/false);
greedy_match_trace.set_stop_node(this);
greedy_match_trace.set_loop_label(&loop_label);
(*alternatives_)[0].node()->Emit(compiler, &greedy_match_trace);
macro_assembler->BindBlock(&greedy_match_failed);
BlockLabel second_choice; // For use in greedy matches.
macro_assembler->BindBlock(&second_choice);
Trace* new_trace = greedy_loop_state->counter_backtrack_trace();
EmitChoices(compiler, alt_gens, 1, new_trace, preload);
macro_assembler->BindBlock(greedy_loop_state->label());
// If we have unwound to the bottom then backtrack.
macro_assembler->CheckGreedyLoop(trace->backtrack());
// Otherwise try the second priority at an earlier position.
macro_assembler->AdvanceCurrentPosition(-text_length);
macro_assembler->GoTo(&second_choice);
return new_trace;
}
intptr_t ChoiceNode::EmitOptimizedUnanchoredSearch(RegExpCompiler* compiler,
Trace* trace) {
intptr_t eats_at_least = PreloadState::kEatsAtLeastNotYetInitialized;
if (alternatives_->length() != 2) return eats_at_least;
GuardedAlternative alt1 = alternatives_->At(1);
if (alt1.guards() != nullptr && alt1.guards()->length() != 0) {
return eats_at_least;
}
RegExpNode* eats_anything_node = alt1.node();
if (eats_anything_node->GetSuccessorOfOmnivorousTextNode(compiler) != this) {
return eats_at_least;
}
// Really we should be creating a new trace when we execute this function,
// but there is no need, because the code it generates cannot backtrack, and
// we always arrive here with a trivial trace (since it's the entry to a
// loop. That also implies that there are no preloaded characters, which is
// good, because it means we won't be violating any assumptions by
// overwriting those characters with new load instructions.
ASSERT(trace->is_trivial());
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
// At this point we know that we are at a non-greedy loop that will eat
// any character one at a time. Any non-anchored regexp has such a
// loop prepended to it in order to find where it starts. We look for
// a pattern of the form ...abc... where we can look 6 characters ahead
// and step forwards 3 if the character is not one of abc. Abc need
// not be atoms, they can be any reasonably limited character class or
// small alternation.
BoyerMooreLookahead* bm = bm_info(false);
if (bm == nullptr) {
eats_at_least = Utils::Minimum(
kMaxLookaheadForBoyerMoore,
EatsAtLeast(kMaxLookaheadForBoyerMoore, kRecursionBudget, false));
if (eats_at_least >= 1) {
bm = new (Z) BoyerMooreLookahead(eats_at_least, compiler, Z);
GuardedAlternative alt0 = alternatives_->At(0);
alt0.node()->FillInBMInfo(0, kRecursionBudget, bm, false);
}
}
if (bm != nullptr) {
bm->EmitSkipInstructions(macro_assembler);
}
return eats_at_least;
}
void ChoiceNode::EmitChoices(RegExpCompiler* compiler,
AlternativeGenerationList* alt_gens,
intptr_t first_choice,
Trace* trace,
PreloadState* preload) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
SetUpPreLoad(compiler, trace, preload);
// For now we just call all choices one after the other. The idea ultimately
// is to use the Dispatch table to try only the relevant ones.
intptr_t choice_count = alternatives_->length();
intptr_t new_flush_budget = trace->flush_budget() / choice_count;
for (intptr_t i = first_choice; i < choice_count; i++) {
bool is_last = i == choice_count - 1;
bool fall_through_on_failure = !is_last;
GuardedAlternative alternative = alternatives_->At(i);
AlternativeGeneration* alt_gen = alt_gens->at(i);
alt_gen->quick_check_details.set_characters(preload->preload_characters_);
ZoneGrowableArray<Guard*>* guards = alternative.guards();
intptr_t guard_count = (guards == nullptr) ? 0 : guards->length();
Trace new_trace(*trace);
new_trace.set_characters_preloaded(
preload->preload_is_current_ ? preload->preload_characters_ : 0);
if (preload->preload_has_checked_bounds_) {
new_trace.set_bound_checked_up_to(preload->preload_characters_);
}
new_trace.quick_check_performed()->Clear();
if (not_at_start_) new_trace.set_at_start(Trace::FALSE_VALUE);
if (!is_last) {
new_trace.set_backtrack(&alt_gen->after);
}
alt_gen->expects_preload = preload->preload_is_current_;
bool generate_full_check_inline = false;
if (kRegexpOptimization &&
try_to_emit_quick_check_for_alternative(i == 0) &&
alternative.node()->EmitQuickCheck(
compiler, trace, &new_trace, preload->preload_has_checked_bounds_,
&alt_gen->possible_success, &alt_gen->quick_check_details,
fall_through_on_failure)) {
// Quick check was generated for this choice.
preload->preload_is_current_ = true;
preload->preload_has_checked_bounds_ = true;
// If we generated the quick check to fall through on possible success,
// we now need to generate the full check inline.
if (!fall_through_on_failure) {
macro_assembler->BindBlock(&alt_gen->possible_success);
new_trace.set_quick_check_performed(&alt_gen->quick_check_details);
new_trace.set_characters_preloaded(preload->preload_characters_);
new_trace.set_bound_checked_up_to(preload->preload_characters_);
generate_full_check_inline = true;
}
} else if (alt_gen->quick_check_details.cannot_match()) {
if (!fall_through_on_failure) {
macro_assembler->GoTo(trace->backtrack());
}
continue;
} else {
// No quick check was generated. Put the full code here.
// If this is not the first choice then there could be slow checks from
// previous cases that go here when they fail. There's no reason to
// insist that they preload characters since the slow check we are about
// to generate probably can't use it.
if (i != first_choice) {
alt_gen->expects_preload = false;
new_trace.InvalidateCurrentCharacter();
}
generate_full_check_inline = true;
}
if (generate_full_check_inline) {
if (new_trace.actions() != nullptr) {
new_trace.set_flush_budget(new_flush_budget);
}
for (intptr_t j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->At(j), &new_trace);
}
alternative.node()->Emit(compiler, &new_trace);
preload->preload_is_current_ = false;
}
macro_assembler->BindBlock(&alt_gen->after);
}
}
void ChoiceNode::EmitOutOfLineContinuation(RegExpCompiler* compiler,
Trace* trace,
GuardedAlternative alternative,
AlternativeGeneration* alt_gen,
intptr_t preload_characters,
bool next_expects_preload) {
if (!alt_gen->possible_success.is_linked()) return;
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
macro_assembler->BindBlock(&alt_gen->possible_success);
Trace out_of_line_trace(*trace);
out_of_line_trace.set_characters_preloaded(preload_characters);
out_of_line_trace.set_quick_check_performed(&alt_gen->quick_check_details);
if (not_at_start_) out_of_line_trace.set_at_start(Trace::FALSE_VALUE);
ZoneGrowableArray<Guard*>* guards = alternative.guards();
intptr_t guard_count = (guards == nullptr) ? 0 : guards->length();
if (next_expects_preload) {
BlockLabel reload_current_char;
out_of_line_trace.set_backtrack(&reload_current_char);
for (intptr_t j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->At(j), &out_of_line_trace);
}
alternative.node()->Emit(compiler, &out_of_line_trace);
macro_assembler->BindBlock(&reload_current_char);
// Reload the current character, since the next quick check expects that.
// We don't need to check bounds here because we only get into this
// code through a quick check which already did the checked load.
macro_assembler->LoadCurrentCharacter(trace->cp_offset(), nullptr, false,
preload_characters);
macro_assembler->GoTo(&(alt_gen->after));
} else {
out_of_line_trace.set_backtrack(&(alt_gen->after));
for (intptr_t j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->At(j), &out_of_line_trace);
}
alternative.node()->Emit(compiler, &out_of_line_trace);
}
}
void ActionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
RecursionCheck rc(compiler);
switch (action_type_) {
case STORE_POSITION: {
Trace::DeferredCapture new_capture(data_.u_position_register.reg,
data_.u_position_register.is_capture,
trace);
Trace new_trace = *trace;
new_trace.add_action(&new_capture);
on_success()->Emit(compiler, &new_trace);
break;
}
case INCREMENT_REGISTER: {
Trace::DeferredIncrementRegister new_increment(
data_.u_increment_register.reg);
Trace new_trace = *trace;
new_trace.add_action(&new_increment);
on_success()->Emit(compiler, &new_trace);
break;
}
case SET_REGISTER: {
Trace::DeferredSetRegister new_set(data_.u_store_register.reg,
data_.u_store_register.value);
Trace new_trace = *trace;
new_trace.add_action(&new_set);
on_success()->Emit(compiler, &new_trace);
break;
}
case CLEAR_CAPTURES: {
Trace::DeferredClearCaptures new_capture(Interval(
data_.u_clear_captures.range_from, data_.u_clear_captures.range_to));
Trace new_trace = *trace;
new_trace.add_action(&new_capture);
on_success()->Emit(compiler, &new_trace);
break;
}
case BEGIN_SUBMATCH:
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
} else {
assembler->WriteCurrentPositionToRegister(
data_.u_submatch.current_position_register, 0);
assembler->WriteStackPointerToRegister(
data_.u_submatch.stack_pointer_register);
on_success()->Emit(compiler, trace);
}
break;
case EMPTY_MATCH_CHECK: {
intptr_t start_pos_reg = data_.u_empty_match_check.start_register;
intptr_t stored_pos = 0;
intptr_t rep_reg = data_.u_empty_match_check.repetition_register;
bool has_minimum = (rep_reg != RegExpCompiler::kNoRegister);
bool know_dist = trace->GetStoredPosition(start_pos_reg, &stored_pos);
if (know_dist && !has_minimum && stored_pos == trace->cp_offset()) {
// If we know we haven't advanced and there is no minimum we
// can just backtrack immediately.
assembler->GoTo(trace->backtrack());
} else if (know_dist && stored_pos < trace->cp_offset()) {
// If we know we've advanced we can generate the continuation
// immediately.
on_success()->Emit(compiler, trace);
} else if (!trace->is_trivial()) {
trace->Flush(compiler, this);
} else {
BlockLabel skip_empty_check;
// If we have a minimum number of repetitions we check the current
// number first and skip the empty check if it's not enough.
if (has_minimum) {
intptr_t limit = data_.u_empty_match_check.repetition_limit;
assembler->IfRegisterLT(rep_reg, limit, &skip_empty_check);
}
// If the match is empty we bail out, otherwise we fall through
// to the on-success continuation.
assembler->IfRegisterEqPos(data_.u_empty_match_check.start_register,
trace->backtrack());
assembler->BindBlock(&skip_empty_check);
on_success()->Emit(compiler, trace);
}
break;
}
case POSITIVE_SUBMATCH_SUCCESS: {
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
assembler->ReadCurrentPositionFromRegister(
data_.u_submatch.current_position_register);
assembler->ReadStackPointerFromRegister(
data_.u_submatch.stack_pointer_register);
intptr_t clear_register_count = data_.u_submatch.clear_register_count;
if (clear_register_count == 0) {
on_success()->Emit(compiler, trace);
return;
}
intptr_t clear_registers_from = data_.u_submatch.clear_register_from;
BlockLabel clear_registers_backtrack;
Trace new_trace = *trace;
new_trace.set_backtrack(&clear_registers_backtrack);
on_success()->Emit(compiler, &new_trace);
assembler->BindBlock(&clear_registers_backtrack);
intptr_t clear_registers_to =
clear_registers_from + clear_register_count - 1;
assembler->ClearRegisters(clear_registers_from, clear_registers_to);
ASSERT(trace->backtrack() == nullptr);
assembler->Backtrack();
return;
}
default:
UNREACHABLE();
}
}
void BackReferenceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
RecursionCheck rc(compiler);
ASSERT(start_reg_ + 1 == end_reg_);
if (flags_.IgnoreCase()) {
assembler->CheckNotBackReferenceIgnoreCase(
start_reg_, read_backward(), flags_.IsUnicode(), trace->backtrack());
} else {
assembler->CheckNotBackReference(start_reg_, read_backward(),
trace->backtrack());
}
// We are going to advance backward, so we may end up at the start.
if (read_backward()) trace->set_at_start(Trace::UNKNOWN);
// Check that the back reference does not end inside a surrogate pair.
if (flags_.IsUnicode() && !compiler->one_byte()) {
assembler->CheckNotInSurrogatePair(trace->cp_offset(), trace->backtrack());
}
on_success()->Emit(compiler, trace);
}
// -------------------------------------------------------------------
// Dot/dotty output
#ifdef DEBUG
class DotPrinter : public NodeVisitor {
public:
explicit DotPrinter(bool ignore_case) {}
void PrintNode(const char* label, RegExpNode* node);
void Visit(RegExpNode* node);
void PrintAttributes(RegExpNode* from);
void PrintOnFailure(RegExpNode* from, RegExpNode* to);
#define DECLARE_VISIT(Type) virtual void Visit##Type(Type##Node* that);
FOR_EACH_NODE_TYPE(DECLARE_VISIT)
#undef DECLARE_VISIT
};
void DotPrinter::PrintNode(const char* label, RegExpNode* node) {
OS::PrintErr("digraph G {\n graph [label=\"");
for (intptr_t i = 0; label[i] != '\0'; i++) {
switch (label[i]) {
case '\\':
OS::PrintErr("\\\\");
break;
case '"':
OS::PrintErr("\"");
break;
default:
OS::PrintErr("%c", label[i]);
break;
}
}
OS::PrintErr("\"];\n");
Visit(node);
OS::PrintErr("}\n");
}
void DotPrinter::Visit(RegExpNode* node) {
if (node->info()->visited) return;
node->info()->visited = true;
node->Accept(this);
}
void DotPrinter::PrintOnFailure(RegExpNode* from, RegExpNode* on_failure) {
OS::PrintErr(" n%p -> n%p [style=dotted];\n", from, on_failure);
Visit(on_failure);
}
class AttributePrinter : public ValueObject {
public:
AttributePrinter() : first_(true) {}
void PrintSeparator() {
if (first_) {
first_ = false;
} else {
OS::PrintErr("|");
}
}
void PrintBit(const char* name, bool value) {
if (!value) return;
PrintSeparator();
OS::PrintErr("{%s}", name);
}
void PrintPositive(const char* name, intptr_t value) {
if (value < 0) return;
PrintSeparator();
OS::PrintErr("{%s|%" Pd "}", name, value);
}
private:
bool first_;
};
void DotPrinter::PrintAttributes(RegExpNode* that) {
OS::PrintErr(
" a%p [shape=Mrecord, color=grey, fontcolor=grey, "
"margin=0.1, fontsize=10, label=\"{",
that);
AttributePrinter printer;
NodeInfo* info = that->info();
printer.PrintBit("NI", info->follows_newline_interest);
printer.PrintBit("WI", info->follows_word_interest);
printer.PrintBit("SI", info->follows_start_interest);
BlockLabel* label = that->label();
if (label->is_bound()) printer.PrintPositive("@", label->pos());
OS::PrintErr(
"}\"];\n"
" a%p -> n%p [style=dashed, color=grey, arrowhead=none];\n",
that, that);
}
void DotPrinter::VisitChoice(ChoiceNode* that) {
OS::PrintErr(" n%p [shape=Mrecord, label=\"?\"];\n", that);
for (intptr_t i = 0; i < that->alternatives()->length(); i++) {
GuardedAlternative alt = that->alternatives()->At(i);
OS::PrintErr(" n%p -> n%p", that, alt.node());
}
for (intptr_t i = 0; i < that->alternatives()->length(); i++) {
GuardedAlternative alt = that->alternatives()->At(i);
alt.node()->Accept(this);
}
}
void DotPrinter::VisitText(TextNode* that) {
OS::PrintErr(" n%p [label=\"", that);
for (intptr_t i = 0; i < that->elements()->length(); i++) {
if (i > 0) OS::PrintErr(" ");
TextElement elm = that->elements()->At(i);
switch (elm.text_type()) {
case TextElement::ATOM: {
ZoneGrowableArray<uint16_t>* data = elm.atom()->data();
for (intptr_t i = 0; i < data->length(); i++) {
OS::PrintErr("%c", static_cast<char>(data->At(i)));
}
break;
}
case TextElement::CHAR_CLASS: {
RegExpCharacterClass* node = elm.char_class();
OS::PrintErr("[");
if (node->is_negated()) OS::PrintErr("^");
for (intptr_t j = 0; j < node->ranges()->length(); j++) {
CharacterRange range = node->ranges()->At(j);
PrintUtf16(range.from());
OS::PrintErr("-");
PrintUtf16(range.to());
}
OS::PrintErr("]");
break;
}
default:
UNREACHABLE();
}
}
OS::PrintErr("\", shape=box, peripheries=2];\n");
PrintAttributes(that);
OS::PrintErr(" n%p -> n%p;\n", that, that->on_success());
Visit(that->on_success());
}
void DotPrinter::VisitBackReference(BackReferenceNode* that) {
OS::PrintErr(" n%p [label=\"$%" Pd "..$%" Pd "\", shape=doubleoctagon];\n",
that, that->start_register(), that->end_register());
PrintAttributes(that);
OS::PrintErr(" n%p -> n%p;\n", that, that->on_success());
Visit(that->on_success());
}
void DotPrinter::VisitEnd(EndNode* that) {
OS::PrintErr(" n%p [style=bold, shape=point];\n", that);
PrintAttributes(that);
}
void DotPrinter::VisitAssertion(AssertionNode* that) {
OS::PrintErr(" n%p [", that);
switch (that->assertion_type()) {
case AssertionNode::AT_END:
OS::PrintErr("label=\"$\", shape=septagon");
break;
case AssertionNode::AT_START:
OS::PrintErr("label=\"^\", shape=septagon");
break;
case AssertionNode::AT_BOUNDARY:
OS::PrintErr("label=\"\\b\", shape=septagon");
break;
case AssertionNode::AT_NON_BOUNDARY:
OS::PrintErr("label=\"\\B\", shape=septagon");
break;
case AssertionNode::AFTER_NEWLINE:
OS::PrintErr("label=\"(?<=\\n)\", shape=septagon");
break;
}
OS::PrintErr("];\n");
PrintAttributes(that);
RegExpNode* successor = that->on_success();
OS::PrintErr(" n%p -> n%p;\n", that, successor);
Visit(successor);
}
void DotPrinter::VisitAction(ActionNode* that) {
OS::PrintErr(" n%p [", that);
switch (that->action_type_) {
case ActionNode::SET_REGISTER:
OS::PrintErr("label=\"$%" Pd ":=%" Pd "\", shape=octagon",
that->data_.u_store_register.reg,
that->data_.u_store_register.value);
break;
case ActionNode::INCREMENT_REGISTER:
OS::PrintErr("label=\"$%" Pd "++\", shape=octagon",
that->data_.u_increment_register.reg);
break;
case ActionNode::STORE_POSITION:
OS::PrintErr("label=\"$%" Pd ":=$pos\", shape=octagon",
that->data_.u_position_register.reg);
break;
case ActionNode::BEGIN_SUBMATCH:
OS::PrintErr("label=\"$%" Pd ":=$pos,begin\", shape=septagon",
that->data_.u_submatch.current_position_register);
break;
case ActionNode::POSITIVE_SUBMATCH_SUCCESS:
OS::PrintErr("label=\"escape\", shape=septagon");
break;
case ActionNode::EMPTY_MATCH_CHECK:
OS::PrintErr("label=\"$%" Pd "=$pos?,$%" Pd "<%" Pd "?\", shape=septagon",
that->data_.u_empty_match_check.start_register,
that->data_.u_empty_match_check.repetition_register,
that->data_.u_empty_match_check.repetition_limit);
break;
case ActionNode::CLEAR_CAPTURES: {
OS::PrintErr("label=\"clear $%" Pd " to $%" Pd "\", shape=septagon",
that->data_.u_clear_captures.range_from,
that->data_.u_clear_captures.range_to);
break;
}
}
OS::PrintErr("];\n");
PrintAttributes(that);
RegExpNode* successor = that->on_success();
OS::PrintErr(" n%p -> n%p;\n", that, successor);
Visit(successor);
}
void RegExpEngine::DotPrint(const char* label,
RegExpNode* node,
bool ignore_case) {
DotPrinter printer(ignore_case);
printer.PrintNode(label, node);
}
#endif // DEBUG
// -------------------------------------------------------------------
// Tree to graph conversion
// The zone in which we allocate graph nodes.
#define OZ (on_success->zone())
RegExpNode* RegExpAtom::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneGrowableArray<TextElement>* elms =
new (OZ) ZoneGrowableArray<TextElement>(1);
elms->Add(TextElement::Atom(this));
return new (OZ) TextNode(elms, compiler->read_backward(), on_success);
}
RegExpNode* RegExpText::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneGrowableArray<TextElement>* elms =
new (OZ) ZoneGrowableArray<TextElement>(1);
for (intptr_t i = 0; i < elements()->length(); i++) {
elms->Add(elements()->At(i));
}
return new (OZ) TextNode(elms, compiler->read_backward(), on_success);
}
static bool CompareInverseRanges(ZoneGrowableArray<CharacterRange>* ranges,
const int32_t* special_class,
intptr_t length) {
length--; // Remove final kRangeEndMarker.
ASSERT(special_class[length] == kRangeEndMarker);
ASSERT(ranges->length() != 0);
ASSERT(length != 0);
ASSERT(special_class[0] != 0);
if (ranges->length() != (length >> 1) + 1) {
return false;
}
CharacterRange range = ranges->At(0);
if (range.from() != 0) {
return false;
}
for (intptr_t i = 0; i < length; i += 2) {
if (special_class[i] != (range.to() + 1)) {
return false;
}
range = ranges->At((i >> 1) + 1);
if (special_class[i + 1] != range.from()) {
return false;
}
}
if (range.to() != Utf::kMaxCodePoint) {
return false;
}
return true;
}
static bool CompareRanges(ZoneGrowableArray<CharacterRange>* ranges,
const int32_t* special_class,
intptr_t length) {
length--; // Remove final kRangeEndMarker.
ASSERT(special_class[length] == kRangeEndMarker);
if (ranges->length() * 2 != length) {
return false;
}
for (intptr_t i = 0; i < length; i += 2) {
CharacterRange range = ranges->At(i >> 1);
if (range.from() != special_class[i] ||
range.to() != special_class[i + 1] - 1) {
return false;
}
}
return true;
}
bool RegExpCharacterClass::is_standard() {
// TODO(lrn): Remove need for this function, by not throwing away information
// along the way.
if (is_negated()) {
return false;
}
if (set_.is_standard()) {
return true;
}
if (CompareRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type('s');
return true;
}
if (CompareInverseRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type('S');
return true;
}
if (CompareInverseRanges(set_.ranges(), kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type('.');
return true;
}
if (CompareRanges(set_.ranges(), kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type('n');
return true;
}
if (CompareRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type('w');
return true;
}
if (CompareInverseRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type('W');
return true;
}
return false;
}
UnicodeRangeSplitter::UnicodeRangeSplitter(
Zone* zone,
ZoneGrowableArray<CharacterRange>* base)
: zone_(zone),
table_(zone),
bmp_(nullptr),
lead_surrogates_(nullptr),
trail_surrogates_(nullptr),
non_bmp_(nullptr) {
// The unicode range splitter categorizes given character ranges into:
// - Code points from the BMP representable by one code unit.
// - Code points outside the BMP that need to be split into surrogate pairs.
// - Lone lead surrogates.
// - Lone trail surrogates.
// Lone surrogates are valid code points, even though no actual characters.
// They require special matching to make sure we do not split surrogate pairs.
// We use the dispatch table to accomplish this. The base range is split up
// by the table by the overlay ranges, and the Call callback is used to
// filter and collect ranges for each category.
for (intptr_t i = 0; i < base->length(); i++) {
table_.AddRange(base->At(i), kBase, zone_);
}
// Add overlay ranges.
table_.AddRange(CharacterRange::Range(0, Utf16::kLeadSurrogateStart - 1),
kBmpCodePoints, zone_);
table_.AddRange(CharacterRange::Range(Utf16::kLeadSurrogateStart,
Utf16::kLeadSurrogateEnd),
kLeadSurrogates, zone_);
table_.AddRange(CharacterRange::Range(Utf16::kTrailSurrogateStart,
Utf16::kTrailSurrogateEnd),
kTrailSurrogates, zone_);
table_.AddRange(
CharacterRange::Range(Utf16::kTrailSurrogateEnd + 1, Utf16::kMaxCodeUnit),
kBmpCodePoints, zone_);
table_.AddRange(
CharacterRange::Range(Utf16::kMaxCodeUnit + 1, Utf::kMaxCodePoint),
kNonBmpCodePoints, zone_);
table_.ForEach(this);
}
void UnicodeRangeSplitter::Call(uint32_t from, ChoiceTable::Entry entry) {
OutSet* outset = entry.out_set();
if (!outset->Get(kBase)) return;
ZoneGrowableArray<CharacterRange>** target = nullptr;
if (outset->Get(kBmpCodePoints)) {
target = &bmp_;
} else if (outset->Get(kLeadSurrogates)) {
target = &lead_surrogates_;
} else if (outset->Get(kTrailSurrogates)) {
target = &trail_surrogates_;
} else {
ASSERT(outset->Get(kNonBmpCodePoints));
target = &non_bmp_;
}
if (*target == nullptr) {
*target = new (zone_) ZoneGrowableArray<CharacterRange>(2);
}
(*target)->Add(CharacterRange::Range(entry.from(), entry.to()));
}
void AddBmpCharacters(RegExpCompiler* compiler,
ChoiceNode* result,
RegExpNode* on_success,
UnicodeRangeSplitter* splitter) {
ZoneGrowableArray<CharacterRange>* bmp = splitter->bmp();
if (bmp == nullptr) return;
result->AddAlternative(GuardedAlternative(TextNode::CreateForCharacterRanges(
bmp, compiler->read_backward(), on_success, RegExpFlags())));
}
void AddNonBmpSurrogatePairs(RegExpCompiler* compiler,
ChoiceNode* result,
RegExpNode* on_success,
UnicodeRangeSplitter* splitter) {
ZoneGrowableArray<CharacterRange>* non_bmp = splitter->non_bmp();
if (non_bmp == nullptr) return;
ASSERT(!compiler->one_byte());
CharacterRange::Canonicalize(non_bmp);
for (int i = 0; i < non_bmp->length(); i++) {
// Match surrogate pair.
// E.g. [\u10005-\u11005] becomes
// \ud800[\udc05-\udfff]|
// [\ud801-\ud803][\udc00-\udfff]|
// \ud804[\udc00-\udc05]
uint32_t from = non_bmp->At(i).from();
uint32_t to = non_bmp->At(i).to();
uint16_t from_points[2];
Utf16::Encode(from, from_points);
uint16_t to_points[2];
Utf16::Encode(to, to_points);
if (from_points[0] == to_points[0]) {
// The lead surrogate is the same.
result->AddAlternative(
GuardedAlternative(TextNode::CreateForSurrogatePair(
CharacterRange::Singleton(from_points[0]),
CharacterRange::Range(from_points[1], to_points[1]),
compiler->read_backward(), on_success, RegExpFlags())));
} else {
if (from_points[1] != Utf16::kTrailSurrogateStart) {
// Add [from_l][from_t-\udfff]
result->AddAlternative(
GuardedAlternative(TextNode::CreateForSurrogatePair(
CharacterRange::Singleton(from_points[0]),
CharacterRange::Range(from_points[1],
Utf16::kTrailSurrogateEnd),
compiler->read_backward(), on_success, RegExpFlags())));
from_points[0]++;
}
if (to_points[1] != Utf16::kTrailSurrogateEnd) {
// Add [to_l][\udc00-to_t]
result->AddAlternative(
GuardedAlternative(TextNode::CreateForSurrogatePair(
CharacterRange::Singleton(to_points[0]),
CharacterRange::Range(Utf16::kTrailSurrogateStart,
to_points[1]),
compiler->read_backward(), on_success, RegExpFlags())));
to_points[0]--;
}
if (from_points[0] <= to_points[0]) {
// Add [from_l-to_l][\udc00-\udfff]
result->AddAlternative(
GuardedAlternative(TextNode::CreateForSurrogatePair(
CharacterRange::Range(from_points[0], to_points[0]),
CharacterRange::Range(Utf16::kTrailSurrogateStart,
Utf16::kTrailSurrogateEnd),
compiler->read_backward(), on_success, RegExpFlags())));
}
}
}
}
RegExpNode* NegativeLookaroundAgainstReadDirectionAndMatch(
RegExpCompiler* compiler,
ZoneGrowableArray<CharacterRange>* lookbehind,
ZoneGrowableArray<CharacterRange>* match,
RegExpNode* on_success,
bool read_backward,
RegExpFlags flags) {
RegExpNode* match_node = TextNode::CreateForCharacterRanges(
match, read_backward, on_success, flags);
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
RegExpLookaround::Builder lookaround(false, match_node, stack_register,
position_register);
RegExpNode* negative_match = TextNode::CreateForCharacterRanges(
lookbehind, !read_backward, lookaround.on_match_success(), flags);
return lookaround.ForMatch(negative_match);
}
RegExpNode* MatchAndNegativeLookaroundInReadDirection(
RegExpCompiler* compiler,
ZoneGrowableArray<CharacterRange>* match,
ZoneGrowableArray<CharacterRange>* lookahead,
RegExpNode* on_success,
bool read_backward,
RegExpFlags flags) {
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
RegExpLookaround::Builder lookaround(false, on_success, stack_register,
position_register);
RegExpNode* negative_match = TextNode::CreateForCharacterRanges(
lookahead, read_backward, lookaround.on_match_success(), flags);
return TextNode::CreateForCharacterRanges(
match, read_backward, lookaround.ForMatch(negative_match), flags);
}
void AddLoneLeadSurrogates(RegExpCompiler* compiler,
ChoiceNode* result,
RegExpNode* on_success,
UnicodeRangeSplitter* splitter) {
auto lead_surrogates = splitter->lead_surrogates();
if (lead_surrogates == nullptr) return;
// E.g. \ud801 becomes \ud801(?![\udc00-\udfff]).
auto trail_surrogates = CharacterRange::List(
on_success->zone(), CharacterRange::Range(Utf16::kTrailSurrogateStart,
Utf16::kTrailSurrogateEnd));
RegExpNode* match;
if (compiler->read_backward()) {
// Reading backward. Assert that reading forward, there is no trail
// surrogate, and then backward match the lead surrogate.
match = NegativeLookaroundAgainstReadDirectionAndMatch(
compiler, trail_surrogates, lead_surrogates, on_success, true,
RegExpFlags());
} else {
// Reading forward. Forward match the lead surrogate and assert that
// no trail surrogate follows.
match = MatchAndNegativeLookaroundInReadDirection(
compiler, lead_surrogates, trail_surrogates, on_success, false,
RegExpFlags());
}
result->AddAlternative(GuardedAlternative(match));
}
void AddLoneTrailSurrogates(RegExpCompiler* compiler,
ChoiceNode* result,
RegExpNode* on_success,
UnicodeRangeSplitter* splitter) {
auto trail_surrogates = splitter->trail_surrogates();
if (trail_surrogates == nullptr) return;
// E.g. \udc01 becomes (?<![\ud800-\udbff])\udc01
auto lead_surrogates = CharacterRange::List(
on_success->zone(), CharacterRange::Range(Utf16::kLeadSurrogateStart,
Utf16::kLeadSurrogateEnd));
RegExpNode* match;
if (compiler->read_backward()) {
// Reading backward. Backward match the trail surrogate and assert that no
// lead surrogate precedes it.
match = MatchAndNegativeLookaroundInReadDirection(
compiler, trail_surrogates, lead_surrogates, on_success, true,
RegExpFlags());
} else {
// Reading forward. Assert that reading backward, there is no lead
// surrogate, and then forward match the trail surrogate.
match = NegativeLookaroundAgainstReadDirectionAndMatch(
compiler, lead_surrogates, trail_surrogates, on_success, false,
RegExpFlags());
}
result->AddAlternative(GuardedAlternative(match));
}
RegExpNode* UnanchoredAdvance(RegExpCompiler* compiler,
RegExpNode* on_success) {
// This implements ES2015 21.2.5.2.3, AdvanceStringIndex.
ASSERT(!compiler->read_backward());
// Advance any character. If the character happens to be a lead surrogate and
// we advanced into the middle of a surrogate pair, it will work out, as
// nothing will match from there. We will have to advance again, consuming
// the associated trail surrogate.
auto range = CharacterRange::List(
on_success->zone(), CharacterRange::Range(0, Utf16::kMaxCodeUnit));
return TextNode::CreateForCharacterRanges(range, false, on_success,
RegExpFlags());
}
void AddUnicodeCaseEquivalents(ZoneGrowableArray<CharacterRange>* ranges) {
ASSERT(CharacterRange::IsCanonical(ranges));
// Micro-optimization to avoid passing large ranges to UnicodeSet::closeOver.
// See also https://crbug.com/v8/6727.
// TODO(sstrickl): This only covers the special case of the {0,0x10FFFF}
// range, which we use frequently internally. But large ranges can also easily
// be created by the user. We might want to have a more general caching
// mechanism for such ranges.
if (ranges->length() == 1 && ranges->At(0).IsEverything(Utf::kMaxCodePoint)) {
return;
}
icu::UnicodeSet set;
for (int i = 0; i < ranges->length(); i++) {
set.add(ranges->At(i).from(), ranges->At(i).to());
}
ranges->Clear();
set.closeOver(USET_CASE_INSENSITIVE);
// Full case mapping map single characters to multiple characters.
// Those are represented as strings in the set. Remove them so that
// we end up with only simple and common case mappings.
set.removeAllStrings();
for (int i = 0; i < set.getRangeCount(); i++) {
ranges->Add(
CharacterRange::Range(set.getRangeStart(i), set.getRangeEnd(i)));
}
// No errors and everything we collected have been ranges.
CharacterRange::Canonicalize(ranges);
}
RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
set_.Canonicalize();
ZoneGrowableArray<CharacterRange>* ranges = this->ranges();
if (flags_.NeedsUnicodeCaseEquivalents()) {
AddUnicodeCaseEquivalents(ranges);
}
if (flags_.IsUnicode() && !compiler->one_byte() &&
!contains_split_surrogate()) {
if (is_negated()) {
ZoneGrowableArray<CharacterRange>* negated =
new ZoneGrowableArray<CharacterRange>(2);
CharacterRange::Negate(ranges, negated);
ranges = negated;
}
if (ranges->length() == 0) {
RegExpCharacterClass* fail =
new RegExpCharacterClass(ranges, RegExpFlags());
return new TextNode(fail, compiler->read_backward(), on_success);
}
if (standard_type() == '*') {
return UnanchoredAdvance(compiler, on_success);
} else {
ChoiceNode* result = new (OZ) ChoiceNode(2, OZ);
UnicodeRangeSplitter splitter(OZ, ranges);
AddBmpCharacters(compiler, result, on_success, &splitter);
AddNonBmpSurrogatePairs(compiler, result, on_success, &splitter);
AddLoneLeadSurrogates(compiler, result, on_success, &splitter);
AddLoneTrailSurrogates(compiler, result, on_success, &splitter);
return result;
}
} else {
return new TextNode(this, compiler->read_backward(), on_success);
}
return new (OZ) TextNode(this, compiler->read_backward(), on_success);
}
RegExpNode* RegExpDisjunction::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneGrowableArray<RegExpTree*>* alternatives = this->alternatives();
intptr_t length = alternatives->length();
ChoiceNode* result = new (OZ) ChoiceNode(length, OZ);
for (intptr_t i = 0; i < length; i++) {
GuardedAlternative alternative(
alternatives->At(i)->ToNode(compiler, on_success));
result->AddAlternative(alternative);
}
return result;
}
RegExpNode* RegExpQuantifier::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return ToNode(min(), max(), is_greedy(), body(), compiler, on_success);
}
// Scoped object to keep track of how much we unroll quantifier loops in the
// regexp graph generator.
class RegExpExpansionLimiter : public ValueObject {
public:
static constexpr intptr_t kMaxExpansionFactor = 6;
RegExpExpansionLimiter(RegExpCompiler* compiler, intptr_t factor)
: compiler_(compiler),
saved_expansion_factor_(compiler->current_expansion_factor()),
ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) {
ASSERT(factor > 0);
if (ok_to_expand_) {
if (factor > kMaxExpansionFactor) {
// Avoid integer overflow of the current expansion factor.
ok_to_expand_ = false;
compiler->set_current_expansion_factor(kMaxExpansionFactor + 1);
} else {
intptr_t new_factor = saved_expansion_factor_ * factor;
ok_to_expand_ = (new_factor <= kMaxExpansionFactor);
compiler->set_current_expansion_factor(new_factor);
}
}
}
~RegExpExpansionLimiter() {
compiler_->set_current_expansion_factor(saved_expansion_factor_);
}
bool ok_to_expand() { return ok_to_expand_; }
private:
RegExpCompiler* compiler_;
intptr_t saved_expansion_factor_;
bool ok_to_expand_;
DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpExpansionLimiter);
};
RegExpNode* RegExpQuantifier::ToNode(intptr_t min,
intptr_t max,
bool is_greedy,
RegExpTree* body,
RegExpCompiler* compiler,
RegExpNode* on_success,
bool not_at_start) {
// x{f, t} becomes this:
//
// (r++)<-.
// | `
// | (x)
// v ^
// (r=0)-->(?)---/ [if r < t]
// |
// [if r >= f] \----> ...
//
// 15.10.2.5 RepeatMatcher algorithm.
// The parser has already eliminated the case where max is 0. In the case
// where max_match is zero the parser has removed the quantifier if min was
// > 0 and removed the atom if min was 0. See AddQuantifierToAtom.
// If we know that we cannot match zero length then things are a little
// simpler since we don't need to make the special zero length match check
// from step 2.1. If the min and max are small we can unroll a little in
// this case.
// Unroll (foo)+ and (foo){3,}
const intptr_t kMaxUnrolledMinMatches = 3;
// Unroll (foo)? and (foo){x,3}
const intptr_t kMaxUnrolledMaxMatches = 3;
if (max == 0) return on_success; // This can happen due to recursion.
bool body_can_be_empty = (body->min_match() == 0);
intptr_t body_start_reg = RegExpCompiler::kNoRegister;
Interval capture_registers = body->CaptureRegisters();
bool needs_capture_clearing = !capture_registers.is_empty();
Zone* zone = compiler->zone();
if (body_can_be_empty) {
body_start_reg = compiler->AllocateRegister();
} else if (kRegexpOptimization && !needs_capture_clearing) {
// Only unroll if there are no captures and the body can't be
// empty.
{
RegExpExpansionLimiter limiter(compiler, min + ((max != min) ? 1 : 0));
if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
intptr_t new_max = (max == kInfinity) ? max : max - min;
// Recurse once to get the loop or optional matches after the fixed
// ones.
RegExpNode* answer =
ToNode(0, new_max, is_greedy, body, compiler, on_success, true);
// Unroll the forced matches from 0 to min. This can cause chains of
// TextNodes (which the parser does not generate). These should be
// combined if it turns out they hinder good code generation.
for (intptr_t i = 0; i < min; i++) {
answer = body->ToNode(compiler, answer);
}
return answer;
}
}
if (max <= kMaxUnrolledMaxMatches && min == 0) {
ASSERT(max > 0); // Due to the 'if' above.
RegExpExpansionLimiter limiter(compiler, max);
if (limiter.ok_to_expand()) {
// Unroll the optional matches up to max.
RegExpNode* answer = on_success;
for (intptr_t i = 0; i < max; i++) {
ChoiceNode* alternation = new (zone) ChoiceNode(2, zone);
if (is_greedy) {
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
alternation->AddAlternative(GuardedAlternative(on_success));
} else {
alternation->AddAlternative(GuardedAlternative(on_success));
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
}
answer = alternation;
if (not_at_start && !compiler->read_backward()) {
alternation->set_not_at_start();
}
}
return answer;
}
}
}
bool has_min = min > 0;
bool has_max = max < RegExpTree::kInfinity;
bool needs_counter = has_min || has_max;
intptr_t reg_ctr = needs_counter ? compiler->AllocateRegister()
: RegExpCompiler::kNoRegister;
LoopChoiceNode* center = new (zone)
LoopChoiceNode(body->min_match() == 0, compiler->read_backward(), zone);
if (not_at_start && !compiler->read_backward()) center->set_not_at_start();
RegExpNode* loop_return =
needs_counter ? static_cast<RegExpNode*>(
ActionNode::IncrementRegister(reg_ctr, center))
: static_cast<RegExpNode*>(center);
if (body_can_be_empty) {
// If the body can be empty we need to check if it was and then
// backtrack.
loop_return =
ActionNode::EmptyMatchCheck(body_start_reg, reg_ctr, min, loop_return);
}
RegExpNode* body_node = body->ToNode(compiler, loop_return);
if (body_can_be_empty) {
// If the body can be empty we need to store the start position
// so we can bail out if it was empty.
body_node = ActionNode::StorePosition(body_start_reg, false, body_node);
}
if (needs_capture_clearing) {
// Before entering the body of this loop we need to clear captures.
body_node = ActionNode::ClearCaptures(capture_registers, body_node);
}
GuardedAlternative body_alt(body_node);
if (has_max) {
Guard* body_guard = new (zone) Guard(reg_ctr, Guard::LT, max);
body_alt.AddGuard(body_guard, zone);
}
GuardedAlternative rest_alt(on_success);
if (has_min) {
Guard* rest_guard = new (zone) Guard(reg_ctr, Guard::GEQ, min);
rest_alt.AddGuard(rest_guard, zone);
}
if (is_greedy) {
center->AddLoopAlternative(body_alt);
center->AddContinueAlternative(rest_alt);
} else {
center->AddContinueAlternative(rest_alt);
center->AddLoopAlternative(body_alt);
}
if (needs_counter) {
return ActionNode::SetRegister(reg_ctr, 0, center);
} else {
return center;
}
}
namespace {
// Desugar \b to (?<=\w)(?=\W)|(?<=\W)(?=\w) and
// \B to (?<=\w)(?=\w)|(?<=\W)(?=\W)
RegExpNode* BoundaryAssertionAsLookaround(RegExpCompiler* compiler,
RegExpNode* on_success,
RegExpAssertion::AssertionType type,
RegExpFlags flags) {
ASSERT(flags.NeedsUnicodeCaseEquivalents());
ZoneGrowableArray<CharacterRange>* word_range =
new ZoneGrowableArray<CharacterRange>(2);
CharacterRange::AddClassEscape('w', word_range, true);
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
ChoiceNode* result = new (OZ) ChoiceNode(2, OZ);
// Add two choices. The (non-)boundary could start with a word or
// a non-word-character.
for (int i = 0; i < 2; i++) {
bool lookbehind_for_word = i == 0;
bool lookahead_for_word =
(type == RegExpAssertion::BOUNDARY) ^ lookbehind_for_word;
// Look to the left.
RegExpLookaround::Builder lookbehind(lookbehind_for_word, on_success,
stack_register, position_register);
RegExpNode* backward = TextNode::CreateForCharacterRanges(
word_range, true, lookbehind.on_match_success(), flags);
// Look to the right.
RegExpLookaround::Builder lookahead(lookahead_for_word,
lookbehind.ForMatch(backward),
stack_register, position_register);
RegExpNode* forward = TextNode::CreateForCharacterRanges(
word_range, false, lookahead.on_match_success(), flags);
result->AddAlternative(GuardedAlternative(lookahead.ForMatch(forward)));
}
return result;
}
} // anonymous namespace
RegExpNode* RegExpAssertion::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
switch (assertion_type()) {
case START_OF_LINE:
return AssertionNode::AfterNewline(on_success);
case START_OF_INPUT:
return AssertionNode::AtStart(on_success);
case BOUNDARY:
return flags_.NeedsUnicodeCaseEquivalents()
? BoundaryAssertionAsLookaround(compiler, on_success, BOUNDARY,
flags_)
: AssertionNode::AtBoundary(on_success);
case NON_BOUNDARY:
return flags_.NeedsUnicodeCaseEquivalents()
? BoundaryAssertionAsLookaround(compiler, on_success,
NON_BOUNDARY, flags_)
: AssertionNode::AtNonBoundary(on_success);
case END_OF_INPUT:
return AssertionNode::AtEnd(on_success);
case END_OF_LINE: {
// Compile $ in multiline regexps as an alternation with a positive
// lookahead in one side and an end-of-input on the other side.
// We need two registers for the lookahead.
intptr_t stack_pointer_register = compiler->AllocateRegister();
intptr_t position_register = compiler->AllocateRegister();
// The ChoiceNode to distinguish between a newline and end-of-input.
ChoiceNode* result = new ChoiceNode(2, on_success->zone());
// Create a newline atom.
ZoneGrowableArray<CharacterRange>* newline_ranges =
new ZoneGrowableArray<CharacterRange>(3);
CharacterRange::AddClassEscape('n', newline_ranges);
RegExpCharacterClass* newline_atom =
new RegExpCharacterClass('n', RegExpFlags());
TextNode* newline_matcher =
new TextNode(newline_atom, /*read_backwards=*/false,
ActionNode::PositiveSubmatchSuccess(
stack_pointer_register, position_register,
0, // No captures inside.
-1, // Ignored if no captures.
on_success));
// Create an end-of-input matcher.
RegExpNode* end_of_line = ActionNode::BeginSubmatch(
stack_pointer_register, position_register, newline_matcher);
// Add the two alternatives to the ChoiceNode.
GuardedAlternative eol_alternative(end_of_line);
result->AddAlternative(eol_alternative);
GuardedAlternative end_alternative(AssertionNode::AtEnd(on_success));
result->AddAlternative(end_alternative);
return result;
}
default:
UNREACHABLE();
}
return on_success;
}
RegExpNode* RegExpBackReference::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return new (OZ) BackReferenceNode(RegExpCapture::StartRegister(index()),
RegExpCapture::EndRegister(index()), flags_,
compiler->read_backward(), on_success);
}
RegExpNode* RegExpEmpty::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return on_success;
}
RegExpLookaround::Builder::Builder(bool is_positive,
RegExpNode* on_success,
intptr_t stack_pointer_register,
intptr_t position_register,
intptr_t capture_register_count,
intptr_t capture_register_start)
: is_positive_(is_positive),
on_success_(on_success),
stack_pointer_register_(stack_pointer_register),
position_register_(position_register) {
if (is_positive_) {
on_match_success_ = ActionNode::PositiveSubmatchSuccess(
stack_pointer_register, position_register, capture_register_count,
capture_register_start, on_success);
} else {
on_match_success_ = new (OZ) NegativeSubmatchSuccess(
stack_pointer_register, position_register, capture_register_count,
capture_register_start, OZ);
}
}
RegExpNode* RegExpLookaround::Builder::ForMatch(RegExpNode* match) {
if (is_positive_) {
return ActionNode::BeginSubmatch(stack_pointer_register_,
position_register_, match);
} else {
Zone* zone = on_success_->zone();
// We use a ChoiceNode to represent the negative lookaround. The first
// alternative is the negative match. On success, the end node backtracks.
// On failure, the second alternative is tried and leads to success.
// NegativeLookaroundChoiceNode is a special ChoiceNode that ignores the
// first exit when calculating quick checks.
ChoiceNode* choice_node = new (zone) NegativeLookaroundChoiceNode(
GuardedAlternative(match), GuardedAlternative(on_success_), zone);
return ActionNode::BeginSubmatch(stack_pointer_register_,
position_register_, choice_node);
}
}
RegExpNode* RegExpLookaround::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
intptr_t stack_pointer_register = compiler->AllocateRegister();
intptr_t position_register = compiler->AllocateRegister();
const intptr_t registers_per_capture = 2;
const intptr_t register_of_first_capture = 2;
intptr_t register_count = capture_count_ * registers_per_capture;
intptr_t register_start =
register_of_first_capture + capture_from_ * registers_per_capture;
RegExpNode* result;
bool was_reading_backward = compiler->read_backward();
compiler->set_read_backward(type() == LOOKBEHIND);
Builder builder(is_positive(), on_success, stack_pointer_register,
position_register, register_count, register_start);
RegExpNode* match = body_->ToNode(compiler, builder.on_match_success());
result = builder.ForMatch(match);
compiler->set_read_backward(was_reading_backward);
return result;
}
RegExpNode* RegExpCapture::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return ToNode(body(), index(), compiler, on_success);
}
RegExpNode* RegExpCapture::ToNode(RegExpTree* body,
intptr_t index,
RegExpCompiler* compiler,
RegExpNode* on_success) {
ASSERT(body != nullptr);
intptr_t start_reg = RegExpCapture::StartRegister(index);
intptr_t end_reg = RegExpCapture::EndRegister(index);
if (compiler->read_backward()) {
intptr_t tmp = end_reg;
end_reg = start_reg;
start_reg = tmp;
}
RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success);
RegExpNode* body_node = body->ToNode(compiler, store_end);
return ActionNode::StorePosition(start_reg, true, body_node);
}
RegExpNode* RegExpAlternative::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneGrowableArray<RegExpTree*>* children = nodes();
RegExpNode* current = on_success;
if (compiler->read_backward()) {
for (intptr_t i = 0; i < children->length(); i++) {
current = children->At(i)->ToNode(compiler, current);
}
} else {
for (intptr_t i = children->length() - 1; i >= 0; i--) {
current = children->At(i)->ToNode(compiler, current);
}
}
return current;
}
static void AddClass(const int32_t* elmv,
intptr_t elmc,
ZoneGrowableArray<CharacterRange>* ranges) {
elmc--;
ASSERT(elmv[elmc] == kRangeEndMarker);
for (intptr_t i = 0; i < elmc; i += 2) {
ASSERT(elmv[i] < elmv[i + 1]);
ranges->Add(CharacterRange(elmv[i], elmv[i + 1] - 1));
}
}
static void AddClassNegated(const int32_t* elmv,
intptr_t elmc,
ZoneGrowableArray<CharacterRange>* ranges) {
elmc--;
ASSERT(elmv[elmc] == kRangeEndMarker);
ASSERT(elmv[0] != 0x0000);
ASSERT(elmv[elmc - 1] != Utf::kMaxCodePoint);
uint16_t last = 0x0000;
for (intptr_t i = 0; i < elmc; i += 2) {
ASSERT(last <= elmv[i] - 1);
ASSERT(elmv[i] < elmv[i + 1]);
ranges->Add(CharacterRange(last, elmv[i] - 1));
last = elmv[i + 1];
}
ranges->Add(CharacterRange(last, Utf::kMaxCodePoint));
}
void CharacterRange::AddClassEscape(uint16_t type,
ZoneGrowableArray<CharacterRange>* ranges,
bool add_unicode_case_equivalents) {
if (add_unicode_case_equivalents && (type == 'w' || type == 'W')) {
// See #sec-runtime-semantics-wordcharacters-abstract-operation
// In case of unicode and ignore_case, we need to create the closure over
// case equivalent characters before negating.
ZoneGrowableArray<CharacterRange>* new_ranges =
new ZoneGrowableArray<CharacterRange>(2);
AddClass(kWordRanges, kWordRangeCount, new_ranges);
AddUnicodeCaseEquivalents(new_ranges);
if (type == 'W') {
ZoneGrowableArray<CharacterRange>* negated =
new ZoneGrowableArray<CharacterRange>(2);
CharacterRange::Negate(new_ranges, negated);
new_ranges = negated;
}
ranges->AddArray(*new_ranges);
return;
}
AddClassEscape(type, ranges);
}
void CharacterRange::AddClassEscape(uint16_t type,
ZoneGrowableArray<CharacterRange>* ranges) {
switch (type) {
case 's':
AddClass(kSpaceRanges, kSpaceRangeCount, ranges);
break;
case 'S':
AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges);
break;
case 'w':
AddClass(kWordRanges, kWordRangeCount, ranges);
break;
case 'W':
AddClassNegated(kWordRanges, kWordRangeCount, ranges);
break;
case 'd':
AddClass(kDigitRanges, kDigitRangeCount, ranges);
break;
case 'D':
AddClassNegated(kDigitRanges, kDigitRangeCount, ranges);
break;
case '.':
AddClassNegated(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges);
break;
// This is not a character range as defined by the spec but a
// convenient shorthand for a character class that matches any
// character.
case '*':
ranges->Add(CharacterRange::Everything());
break;
// This is the set of characters matched by the $ and ^ symbols
// in multiline mode.
case 'n':
AddClass(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges);
break;
default:
UNREACHABLE();
}
}
void CharacterRange::AddCaseEquivalents(
ZoneGrowableArray<CharacterRange>* ranges,
bool is_one_byte,
Zone* zone) {
CharacterRange::Canonicalize(ranges);
int range_count = ranges->length();
for (intptr_t i = 0; i < range_count; i++) {
CharacterRange range = ranges->At(i);
int32_t bottom = range.from();
if (bottom > Utf16::kMaxCodeUnit) continue;
int32_t top = Utils::Minimum(range.to(), Utf16::kMaxCodeUnit);
// Nothing to be done for surrogates
if (bottom >= Utf16::kLeadSurrogateStart &&
top <= Utf16::kTrailSurrogateEnd) {
continue;
}
if (is_one_byte && !RangeContainsLatin1Equivalents(range)) {
if (bottom > Symbols::kMaxOneCharCodeSymbol) continue;
if (top > Symbols::kMaxOneCharCodeSymbol) {
top = Symbols::kMaxOneCharCodeSymbol;
}
}
unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize;
unibrow::Mapping<unibrow::CanonicalizationRange> jsregexp_canonrange;
int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
if (top == bottom) {
// If this is a singleton we just expand the one character.
intptr_t length = jsregexp_uncanonicalize.get(bottom, '\0', chars);
for (intptr_t i = 0; i < length; i++) {
int32_t chr = chars[i];
if (chr != bottom) {
ranges->Add(CharacterRange::Singleton(chars[i]));
}
}
} else {
// If this is a range we expand the characters block by block,
// expanding contiguous subranges (blocks) one at a time.
// The approach is as follows. For a given start character we
// look up the remainder of the block that contains it (represented
// by the end point), for instance we find 'z' if the character
// is 'c'. A block is characterized by the property
// that all characters uncanonicalize in the same way, except that
// each entry in the result is incremented by the distance from the first
// element. So a-z is a block because 'a' uncanonicalizes to ['a', 'A']
// and the k'th letter uncanonicalizes to ['a' + k, 'A' + k].
// Once we've found the end point we look up its uncanonicalization
// and produce a range for each element. For instance for [c-f]
// we look up ['z', 'Z'] and produce [c-f] and [C-F]. We then only
// add a range if it is not already contained in the input, so [c-f]
// will be skipped but [C-F] will be added. If this range is not
// completely contained in a block we do this for all the blocks
// covered by the range (handling characters that is not in a block
// as a "singleton block").
int32_t range[unibrow::Ecma262UnCanonicalize::kMaxWidth];
intptr_t pos = bottom;
while (pos <= top) {
intptr_t length = jsregexp_canonrange.get(pos, '\0', range);
int32_t block_end;
if (length == 0) {
block_end = pos;
} else {
ASSERT(length == 1);
block_end = range[0];
}
intptr_t end = (block_end > top) ? top : block_end;
length = jsregexp_uncanonicalize.get(block_end, '\0', range);
for (intptr_t i = 0; i < length; i++) {
int32_t c = range[i];
int32_t range_from = c - (block_end - pos);
int32_t range_to = c - (block_end - end);
if (!(bottom <= range_from && range_to <= top)) {
ranges->Add(CharacterRange(range_from, range_to));
}
}
pos = end + 1;
}
}
}
}
bool CharacterRange::IsCanonical(ZoneGrowableArray<CharacterRange>* ranges) {
ASSERT(ranges != nullptr);
intptr_t n = ranges->length();
if (n <= 1) return true;
intptr_t max = ranges->At(0).to();
for (intptr_t i = 1; i < n; i++) {
CharacterRange next_range = ranges->At(i);
if (next_range.from() <= max + 1) return false;
max = next_range.to();
}
return true;
}
ZoneGrowableArray<CharacterRange>* CharacterSet::ranges() {
if (ranges_ == nullptr) {
ranges_ = new ZoneGrowableArray<CharacterRange>(2);
CharacterRange::AddClassEscape(standard_set_type_, ranges_);
}
return ranges_;
}
// Move a number of elements in a zone array to another position
// in the same array. Handles overlapping source and target areas.
static void MoveRanges(ZoneGrowableArray<CharacterRange>* list,
intptr_t from,
intptr_t to,
intptr_t count) {
// Ranges are potentially overlapping.
if (from < to) {
for (intptr_t i = count - 1; i >= 0; i--) {
(*list)[to + i] = list->At(from + i);
}
} else {
for (intptr_t i = 0; i < count; i++) {
(*list)[to + i] = list->At(from + i);
}
}
}
static intptr_t InsertRangeInCanonicalList(
ZoneGrowableArray<CharacterRange>* list,
intptr_t count,
CharacterRange insert) {
// Inserts a range into list[0..count[, which must be sorted
// by from value and non-overlapping and non-adjacent, using at most
// list[0..count] for the result. Returns the number of resulting
// canonicalized ranges. Inserting a range may collapse existing ranges into
// fewer ranges, so the return value can be anything in the range 1..count+1.
int32_t from = insert.from();
int32_t to = insert.to();
intptr_t start_pos = 0;
intptr_t end_pos = count;
for (intptr_t i = count - 1; i >= 0; i--) {
CharacterRange current = list->At(i);
if (current.from() > to + 1) {
end_pos = i;
} else if (current.to() + 1 < from) {
start_pos = i + 1;
break;
}
}
// Inserted range overlaps, or is adjacent to, ranges at positions
// [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are
// not affected by the insertion.
// If start_pos == end_pos, the range must be inserted before start_pos.
// if start_pos < end_pos, the entire range from start_pos to end_pos
// must be merged with the insert range.
if (start_pos == end_pos) {
// Insert between existing ranges at position start_pos.
if (start_pos < count) {
MoveRanges(list, start_pos, start_pos + 1, count - start_pos);
}
(*list)[start_pos] = insert;
return count + 1;
}
if (start_pos + 1 == end_pos) {
// Replace single existing range at position start_pos.
CharacterRange to_replace = list->At(start_pos);
intptr_t new_from = Utils::Minimum(to_replace.from(), from);
intptr_t new_to = Utils::Maximum(to_replace.to(), to);
(*list)[start_pos] = CharacterRange(new_from, new_to);
return count;
}
// Replace a number of existing ranges from start_pos to end_pos - 1.
// Move the remaining ranges down.
intptr_t new_from = Utils::Minimum(list->At(start_pos).from(), from);
intptr_t new_to = Utils::Maximum(list->At(end_pos - 1).to(), to);
if (end_pos < count) {
MoveRanges(list, end_pos, start_pos + 1, count - end_pos);
}
(*list)[start_pos] = CharacterRange(new_from, new_to);
return count - (end_pos - start_pos) + 1;
}
void CharacterSet::Canonicalize() {
// Special/default classes are always considered canonical. The result
// of calling ranges() will be sorted.
if (ranges_ == nullptr) return;
CharacterRange::Canonicalize(ranges_);
}
void CharacterRange::Canonicalize(
ZoneGrowableArray<CharacterRange>* character_ranges) {
if (character_ranges->length() <= 1) return;
// Check whether ranges are already canonical (increasing, non-overlapping,
// non-adjacent).
intptr_t n = character_ranges->length();
intptr_t max = character_ranges->At(0).to();
intptr_t i = 1;
while (i < n) {
CharacterRange current = character_ranges->At(i);
if (current.from() <= max + 1) {
break;
}
max = current.to();
i++;
}
// Canonical until the i'th range. If that's all of them, we are done.
if (i == n) return;
// The ranges at index i and forward are not canonicalized. Make them so by
// doing the equivalent of insertion sort (inserting each into the previous
// list, in order).
// Notice that inserting a range can reduce the number of ranges in the
// result due to combining of adjacent and overlapping ranges.
intptr_t read = i; // Range to insert.
intptr_t num_canonical = i; // Length of canonicalized part of list.
do {
num_canonical = InsertRangeInCanonicalList(character_ranges, num_canonical,
character_ranges->At(read));
read++;
} while (read < n);
character_ranges->TruncateTo(num_canonical);
ASSERT(CharacterRange::IsCanonical(character_ranges));
}
void CharacterRange::Negate(ZoneGrowableArray<CharacterRange>* ranges,
ZoneGrowableArray<CharacterRange>* negated_ranges) {
ASSERT(CharacterRange::IsCanonical(ranges));
ASSERT(negated_ranges->length() == 0);
intptr_t range_count = ranges->length();
uint32_t from = 0;
intptr_t i = 0;
if (range_count > 0 && ranges->At(0).from() == 0) {
from = ranges->At(0).to();
i = 1;
}
while (i < range_count) {
CharacterRange range = ranges->At(i);
negated_ranges->Add(CharacterRange(from + 1, range.from() - 1));
from = range.to();
i++;
}
if (from < Utf::kMaxCodePoint) {
negated_ranges->Add(CharacterRange(from + 1, Utf::kMaxCodePoint));
}
}
// -------------------------------------------------------------------
// Splay tree
// Workaround for the fact that ZoneGrowableArray does not have contains().
static bool ArrayContains(ZoneGrowableArray<unsigned>* array, unsigned value) {
for (intptr_t i = 0; i < array->length(); i++) {
if (array->At(i) == value) {
return true;
}
}
return false;
}
OutSet* OutSet::Extend(unsigned value, Zone* zone) {
if (Get(value)) return this;
if (successors() != nullptr) {
for (int i = 0; i < successors()->length(); i++) {
OutSet* successor = successors()->At(i);
if (successor->Get(value)) return successor;
}
} else {
successors_ = new (zone) ZoneGrowableArray<OutSet*>(2);
}
OutSet* result = new (zone) OutSet(first_, remaining_);
result->Set(value, zone);
successors()->Add(result);
return result;
}
void OutSet::Set(unsigned value, Zone* zone) {
if (value < kFirstLimit) {
first_ |= (1 << value);
} else {
if (remaining_ == nullptr)
remaining_ = new (zone) ZoneGrowableArray<unsigned>(1);
bool remaining_contains_value = ArrayContains(remaining_, value);
if (remaining_->is_empty() || !remaining_contains_value) {
remaining_->Add(value);
}
}
}
bool OutSet::Get(unsigned value) const {
if (value < kFirstLimit) {
return (first_ & (1 << value)) != 0;
} else if (remaining_ == nullptr) {
return false;
} else {
return ArrayContains(remaining_, value);
}
}
const int32_t ChoiceTable::Config::kNoKey = Utf::kInvalidChar;
void ChoiceTable::AddRange(CharacterRange full_range,
int32_t value,
Zone* zone) {
CharacterRange current = full_range;
if (tree()->is_empty()) {
// If this is the first range we just insert into the table.
ZoneSplayTree<Config>::Locator loc;
bool inserted = tree()->Insert(current.from(), &loc);
ASSERT(inserted);
USE(inserted);
loc.set_value(
Entry(current.from(), current.to(), empty()->Extend(value, zone)));
return;
}
// First see if there is a range to the left of this one that
// overlaps.
ZoneSplayTree<Config>::Locator loc;
if (tree()->FindGreatestLessThan(current.from(), &loc)) {
Entry* entry = &loc.value();
// If we've found a range that overlaps with this one, and it
// starts strictly to the left of this one, we have to fix it
// because the following code only handles ranges that start on
// or after the start point of the range we're adding.
if (entry->from() < current.from() && entry->to() >= current.from()) {
// Snap the overlapping range in half around the start point of
// the range we're adding.
CharacterRange left =
CharacterRange::Range(entry->from(), current.from() - 1);
CharacterRange right = CharacterRange::Range(current.from(), entry->to());
// The left part of the overlapping range doesn't overlap.
// Truncate the whole entry to be just the left part.
entry->set_to(left.to());
// The right part is the one that overlaps. We add this part
// to the map and let the next step deal with merging it with
// the range we're adding.
ZoneSplayTree<Config>::Locator loc;
bool inserted = tree()->Insert(right.from(), &loc);
ASSERT(inserted);
USE(inserted);
loc.set_value(Entry(right.from(), right.to(), entry->out_set()));
}
}
while (current.is_valid()) {
if (tree()->FindLeastGreaterThan(current.from(), &loc) &&
(loc.value().from() <= current.to()) &&
(loc.value().to() >= current.from())) {
Entry* entry = &loc.value();
// We have overlap. If there is space between the start point of
// the range we're adding and where the overlapping range starts
// then we have to add a range covering just that space.
if (current.from() < entry->from()) {
ZoneSplayTree<Config>::Locator ins;
bool inserted = tree()->Insert(current.from(), &ins);
ASSERT(inserted);
USE(inserted);
ins.set_value(Entry(current.from(), entry->from() - 1,
empty()->Extend(value, zone)));
current.set_from(entry->from());
}
ASSERT(current.from() == entry->from());
// If the overlapping range extends beyond the one we want to add
// we have to snap the right part off and add it separately.
if (entry->to() > current.to()) {
ZoneSplayTree<Config>::Locator ins;
bool inserted = tree()->Insert(current.to() + 1, &ins);
ASSERT(inserted);
USE(inserted);
ins.set_value(Entry(current.to() + 1, entry->to(), entry->out_set()));
entry->set_to(current.to());
}
ASSERT(entry->to() <= current.to());
// The overlapping range is now completely contained by the range
// we're adding so we can just update it and move the start point
// of the range we're adding just past it.
entry->AddValue(value, zone);
ASSERT(entry->to() + 1 > current.from());
current.set_from(entry->to() + 1);
} else {
// There is no overlap so we can just add the range
ZoneSplayTree<Config>::Locator ins;
bool inserted = tree()->Insert(current.from(), &ins);
ASSERT(inserted);
USE(inserted);
ins.set_value(
Entry(current.from(), current.to(), empty()->Extend(value, zone)));
break;
}
}
}
OutSet* ChoiceTable::Get(int32_t value) {
ZoneSplayTree<Config>::Locator loc;
if (!tree()->FindGreatestLessThan(value, &loc)) return empty();
Entry* entry = &loc.value();
if (value <= entry->to())
return entry->out_set();
else
return empty();
}
// -------------------------------------------------------------------
// Analysis
void Analysis::EnsureAnalyzed(RegExpNode* that) {
if (that->info()->been_analyzed || that->info()->being_analyzed) return;
that->info()->being_analyzed = true;
that->Accept(this);
that->info()->being_analyzed = false;
that->info()->been_analyzed = true;
}
void Analysis::VisitEnd(EndNode* that) {
// nothing to do
}
void TextNode::CalculateOffsets() {
intptr_t element_count = elements()->length();
// Set up the offsets of the elements relative to the start. This is a fixed
// quantity since a TextNode can only contain fixed-width things.
intptr_t cp_offset = 0;
for (intptr_t i = 0; i < element_count; i++) {
TextElement& elm = (*elements())[i];
elm.set_cp_offset(cp_offset);
cp_offset += elm.length();
}
}
void Analysis::VisitText(TextNode* that) {
that->MakeCaseIndependent(is_one_byte_);
EnsureAnalyzed(that->on_success());
if (!has_failed()) {
that->CalculateOffsets();
}
}
void Analysis::VisitAction(ActionNode* that) {
RegExpNode* target = that->on_success();
EnsureAnalyzed(target);
if (!has_failed()) {
// If the next node is interested in what it follows then this node
// has to be interested too so it can pass the information on.
that->info()->AddFromFollowing(target->info());
}
}
void Analysis::VisitChoice(ChoiceNode* that) {
NodeInfo* info = that->info();
for (intptr_t i = 0; i < that->alternatives()->length(); i++) {
RegExpNode* node = (*that->alternatives())[i].node();
EnsureAnalyzed(node);
if (has_failed()) return;
// Anything the following nodes need to know has to be known by
// this node also, so it can pass it on.
info->AddFromFollowing(node->info());
}
}
void Analysis::VisitLoopChoice(LoopChoiceNode* that) {
NodeInfo* info = that->info();
for (intptr_t i = 0; i < that->alternatives()->length(); i++) {
RegExpNode* node = (*that->alternatives())[i].node();
if (node != that->loop_node()) {
EnsureAnalyzed(node);
if (has_failed()) return;
info->AddFromFollowing(node->info());
}
}
// Check the loop last since it may need the value of this node
// to get a correct result.
EnsureAnalyzed(that->loop_node());
if (!has_failed()) {
info->AddFromFollowing(that->loop_node()->info());
}
}
void Analysis::VisitBackReference(BackReferenceNode* that) {
EnsureAnalyzed(that->on_success());
}
void Analysis::VisitAssertion(AssertionNode* that) {
EnsureAnalyzed(that->on_success());
}
void BackReferenceNode::FillInBMInfo(intptr_t offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
// Working out the set of characters that a backreference can match is too
// hard, so we just say that any character can match.
bm->SetRest(offset);
SaveBMInfo(bm, not_at_start, offset);
}
COMPILE_ASSERT(BoyerMoorePositionInfo::kMapSize ==
RegExpMacroAssembler::kTableSize);
void ChoiceNode::FillInBMInfo(intptr_t offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
ZoneGrowableArray<GuardedAlternative>* alts = alternatives();
budget = (budget - 1) / alts->length();
for (intptr_t i = 0; i < alts->length(); i++) {
GuardedAlternative& alt = (*alts)[i];
if (alt.guards() != nullptr && alt.guards()->length() != 0) {
bm->SetRest(offset); // Give up trying to fill in info.
SaveBMInfo(bm, not_at_start, offset);
return;
}
alt.node()->FillInBMInfo(offset, budget, bm, not_at_start);
}
SaveBMInfo(bm, not_at_start, offset);
}
void TextNode::FillInBMInfo(intptr_t initial_offset,
intptr_t budget,
BoyerMooreLookahead* bm,
bool not_at_start) {
if (initial_offset >= bm->length()) return;
intptr_t offset = initial_offset;
intptr_t max_char = bm->max_char();
for (intptr_t i = 0; i < elements()->length(); i++) {
if (offset >= bm->length()) {
if (initial_offset == 0) set_bm_info(not_at_start, bm);
return;
}
TextElement text = elements()->At(i);
if (text.text_type() == TextElement::ATOM) {
RegExpAtom* atom = text.atom();
for (intptr_t j = 0; j < atom->length(); j++, offset++) {
if (offset >= bm->length()) {
if (initial_offset == 0) set_bm_info(not_at_start, bm);
return;
}
uint16_t character = atom->data()->At(j);
if (atom->flags().IgnoreCase()) {
int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
intptr_t length = GetCaseIndependentLetters(
character, bm->max_char() == Symbols::kMaxOneCharCodeSymbol,
chars);
for (intptr_t j = 0; j < length; j++) {
bm->Set(offset, chars[j]);
}
} else {
if (character <= max_char) bm->Set(offset, character);
}
}
} else {
ASSERT(text.text_type() == TextElement::CHAR_CLASS);
RegExpCharacterClass* char_class = text.char_class();
ZoneGrowableArray<CharacterRange>* ranges = char_class->ranges();
if (char_class->is_negated()) {
bm->SetAll(offset);
} else {
for (intptr_t k = 0; k < ranges->length(); k++) {
const CharacterRange& range = ranges->At(k);
if (range.from() > max_char) continue;
intptr_t to =
Utils::Minimum(max_char, static_cast<intptr_t>(range.to()));
bm->SetInterval(offset, Interval(range.from(), to));
}
}
offset++;
}
}
if (offset >= bm->length()) {
if (initial_offset == 0) set_bm_info(not_at_start, bm);
return;
}
on_success()->FillInBMInfo(offset, budget - 1, bm,
true); // Not at start after a text node.
if (initial_offset == 0) set_bm_info(not_at_start, bm);
}
RegExpNode* OptionallyStepBackToLeadSurrogate(RegExpCompiler* compiler,
RegExpNode* on_success,
RegExpFlags flags) {
// If the regexp matching starts within a surrogate pair, step back
// to the lead surrogate and start matching from there.
ASSERT(!compiler->read_backward());
Zone* zone = compiler->zone();
auto lead_surrogates = CharacterRange::List(
on_success->zone(), CharacterRange::Range(Utf16::kLeadSurrogateStart,
Utf16::kLeadSurrogateEnd));
auto trail_surrogates = CharacterRange::List(
on_success->zone(), CharacterRange::Range(Utf16::kTrailSurrogateStart,
Utf16::kTrailSurrogateEnd));
ChoiceNode* optional_step_back = new (zone) ChoiceNode(2, zone);
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
RegExpNode* step_back = TextNode::CreateForCharacterRanges(
lead_surrogates, /*read_backward=*/true, on_success, flags);
RegExpLookaround::Builder builder(/*is_positive=*/true, step_back,
stack_register, position_register);
RegExpNode* match_trail = TextNode::CreateForCharacterRanges(
trail_surrogates, /*read_backward=*/false, builder.on_match_success(),
flags);
optional_step_back->AddAlternative(
GuardedAlternative(builder.ForMatch(match_trail)));
optional_step_back->AddAlternative(GuardedAlternative(on_success));
return optional_step_back;
}
#if !defined(DART_PRECOMPILED_RUNTIME)
RegExpEngine::CompilationResult RegExpEngine::CompileIR(
RegExpCompileData* data,
const ParsedFunction* parsed_function,
const ZoneGrowableArray<const ICData*>& ic_data_array,
intptr_t osr_id) {
ASSERT(!FLAG_interpret_irregexp);
Zone* zone = Thread::Current()->zone();
const Function& function = parsed_function->function();
const intptr_t specialization_cid = function.string_specialization_cid();
const bool is_sticky = function.is_sticky_specialization();
const bool is_one_byte = (specialization_cid == kOneByteStringCid);
RegExp& regexp = RegExp::Handle(zone, function.regexp());
const String& pattern = String::Handle(zone, regexp.pattern());
ASSERT(!regexp.IsNull());
ASSERT(!pattern.IsNull());
const bool is_global = regexp.flags().IsGlobal();
const bool is_unicode = regexp.flags().IsUnicode();
RegExpCompiler compiler(data->capture_count, is_one_byte);
// TODO(zerny): Frequency sampling is currently disabled because of several
// issues. We do not want to store subject strings in the regexp object since
// they might be long and we should not prevent their garbage collection.
// Passing them to this function explicitly does not help, since we must
// generate exactly the same IR for both the unoptimizing and optimizing
// pipelines (otherwise it gets confused when i.e. deopt id's differ).
// An option would be to store sampling results in the regexp object, but
// I'm not sure the performance gains are relevant enough.
// Wrap the body of the regexp in capture #0.
RegExpNode* captured_body =
RegExpCapture::ToNode(data->tree, 0, &compiler, compiler.accept());
RegExpNode* node = captured_body;
const bool is_end_anchored = data->tree->IsAnchoredAtEnd();
const bool is_start_anchored = data->tree->IsAnchoredAtStart();
intptr_t max_length = data->tree->max_match();
if (!is_start_anchored && !is_sticky) {
// Add a .*? at the beginning, outside the body capture, unless
// this expression is anchored at the beginning or is sticky.
RegExpNode* loop_node = RegExpQuantifier::ToNode(
0, RegExpTree::kInfinity, false,
new (zone) RegExpCharacterClass('*', RegExpFlags()), &compiler,
captured_body, data->contains_anchor);
if (data->contains_anchor) {
// Unroll loop once, to take care of the case that might start
// at the start of input.
ChoiceNode* first_step_node = new (zone) ChoiceNode(2, zone);
first_step_node->AddAlternative(GuardedAlternative(captured_body));
first_step_node->AddAlternative(GuardedAlternative(new (zone) TextNode(
new (zone) RegExpCharacterClass('*', RegExpFlags()),
/*read_backwards=*/false, loop_node)));
node = first_step_node;
} else {
node = loop_node;
}
}
if (is_one_byte) {
node = node->FilterOneByte(RegExpCompiler::kMaxRecursion);
// Do it again to propagate the new nodes to places where they were not
// put because they had not been calculated yet.
if (node != nullptr) {
node = node->FilterOneByte(RegExpCompiler::kMaxRecursion);
}
} else if (is_unicode && (is_global || is_sticky)) {
node = OptionallyStepBackToLeadSurrogate(&compiler, node, regexp.flags());
}
if (node == nullptr) node = new (zone) EndNode(EndNode::BACKTRACK, zone);
data->node = node;
Analysis analysis(is_one_byte);
analysis.EnsureAnalyzed(node);
if (analysis.has_failed()) {
const char* error_message = analysis.error_message();
return CompilationResult(error_message);
}
// Native regexp implementation.
IRRegExpMacroAssembler* macro_assembler = new (zone)
IRRegExpMacroAssembler(specialization_cid, data->capture_count,
parsed_function, ic_data_array, osr_id, zone);
// Inserted here, instead of in Assembler, because it depends on information
// in the AST that isn't replicated in the Node structure.
const intptr_t kMaxBacksearchLimit = 1024;
if (is_end_anchored && !is_start_anchored && !is_sticky &&
max_length < kMaxBacksearchLimit) {
macro_assembler->SetCurrentPositionFromEnd(max_length);
}
if (is_global) {
RegExpMacroAssembler::GlobalMode mode = RegExpMacroAssembler::GLOBAL;
if (data->tree->min_match() > 0) {
mode = RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK;
} else if (is_unicode) {
mode = RegExpMacroAssembler::GLOBAL_UNICODE;
}
macro_assembler->set_global_mode(mode);
}
RegExpEngine::CompilationResult result =
compiler.Assemble(macro_assembler, node, data->capture_count, pattern);
if (FLAG_trace_irregexp) {
macro_assembler->PrintBlocks();
}
return result;
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
RegExpEngine::CompilationResult RegExpEngine::CompileBytecode(
RegExpCompileData* data,
const RegExp& regexp,
bool is_one_byte,
bool is_sticky,
Zone* zone) {
ASSERT(FLAG_interpret_irregexp);
const String& pattern = String::Handle(zone, regexp.pattern());
ASSERT(!regexp.IsNull());
ASSERT(!pattern.IsNull());
const bool is_global = regexp.flags().IsGlobal();
const bool is_unicode = regexp.flags().IsUnicode();
RegExpCompiler compiler(data->capture_count, is_one_byte);
// TODO(zerny): Frequency sampling is currently disabled because of several
// issues. We do not want to store subject strings in the regexp object since
// they might be long and we should not prevent their garbage collection.
// Passing them to this function explicitly does not help, since we must
// generate exactly the same IR for both the unoptimizing and optimizing
// pipelines (otherwise it gets confused when i.e. deopt id's differ).
// An option would be to store sampling results in the regexp object, but
// I'm not sure the performance gains are relevant enough.
// Wrap the body of the regexp in capture #0.
RegExpNode* captured_body =
RegExpCapture::ToNode(data->tree, 0, &compiler, compiler.accept());
RegExpNode* node = captured_body;
bool is_end_anchored = data->tree->IsAnchoredAtEnd();
bool is_start_anchored = data->tree->IsAnchoredAtStart();
intptr_t max_length = data->tree->max_match();
if (!is_start_anchored && !is_sticky) {
// Add a .*? at the beginning, outside the body capture, unless
// this expression is anchored at the beginning.
RegExpNode* loop_node = RegExpQuantifier::ToNode(
0, RegExpTree::kInfinity, false,
new (zone) RegExpCharacterClass('*', RegExpFlags()), &compiler,
captured_body, data->contains_anchor);
if (data->contains_anchor) {
// Unroll loop once, to take care of the case that might start
// at the start of input.
ChoiceNode* first_step_node = new (zone) ChoiceNode(2, zone);
first_step_node->AddAlternative(GuardedAlternative(captured_body));
first_step_node->AddAlternative(GuardedAlternative(new (zone) TextNode(
new (zone) RegExpCharacterClass('*', RegExpFlags()),
/*read_backwards=*/false, loop_node)));
node = first_step_node;
} else {
node = loop_node;
}
}
if (is_one_byte) {
node = node->FilterOneByte(RegExpCompiler::kMaxRecursion);
// Do it again to propagate the new nodes to places where they were not
// put because they had not been calculated yet.
if (node != nullptr) {
node = node->FilterOneByte(RegExpCompiler::kMaxRecursion);
}
} else if (is_unicode && (is_global || is_sticky)) {
node = OptionallyStepBackToLeadSurrogate(&compiler, node, regexp.flags());
}
if (node == nullptr) node = new (zone) EndNode(EndNode::BACKTRACK, zone);
data->node = node;
Analysis analysis(is_one_byte);
analysis.EnsureAnalyzed(node);
if (analysis.has_failed()) {
const char* error_message = analysis.error_message();
return CompilationResult(error_message);
}
// Bytecode regexp implementation.
ZoneGrowableArray<uint8_t> buffer(zone, 1024);
BytecodeRegExpMacroAssembler* macro_assembler =
new (zone) BytecodeRegExpMacroAssembler(&buffer, zone);
// Inserted here, instead of in Assembler, because it depends on information
// in the AST that isn't replicated in the Node structure.
const intptr_t kMaxBacksearchLimit = 1024;
if (is_end_anchored && !is_start_anchored && !is_sticky &&
max_length < kMaxBacksearchLimit) {
macro_assembler->SetCurrentPositionFromEnd(max_length);
}
if (is_global) {
RegExpMacroAssembler::GlobalMode mode = RegExpMacroAssembler::GLOBAL;
if (data->tree->min_match() > 0) {
mode = RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK;
} else if (is_unicode) {
mode = RegExpMacroAssembler::GLOBAL_UNICODE;
}
macro_assembler->set_global_mode(mode);
}
RegExpEngine::CompilationResult result =
compiler.Assemble(macro_assembler, node, data->capture_count, pattern);
if (FLAG_trace_irregexp) {
macro_assembler->PrintBlocks();
}
return result;
}
void CreateSpecializedFunction(Thread* thread,
Zone* zone,
const RegExp& regexp,
intptr_t specialization_cid,
bool sticky,
const Object& owner) {
const intptr_t kParamCount = RegExpMacroAssembler::kParamCount;
const FunctionType& signature =
FunctionType::Handle(zone, FunctionType::New());
const String& pattern = String::Handle(zone, regexp.pattern());
Function& fn =
Function::Handle(zone, Function::New(signature, pattern,
UntaggedFunction::kIrregexpFunction,
true, // Static.
false, // Not const.
false, // Not abstract.
false, // Not external.
false, // Not native.
owner, TokenPosition::kMinSource));
// TODO(zerny): Share these arrays between all irregexp functions.
// TODO(regis): Better, share a common signature.
signature.set_num_fixed_parameters(kParamCount);
signature.set_parameter_types(
Array::Handle(zone, Array::New(kParamCount, Heap::kOld)));
fn.CreateNameArray();
signature.SetParameterTypeAt(RegExpMacroAssembler::kParamRegExpIndex,
Object::dynamic_type());
fn.SetParameterNameAt(RegExpMacroAssembler::kParamRegExpIndex,
Symbols::This());
signature.SetParameterTypeAt(RegExpMacroAssembler::kParamStringIndex,
Object::dynamic_type());
fn.SetParameterNameAt(RegExpMacroAssembler::kParamStringIndex,
Symbols::string_param());
signature.SetParameterTypeAt(RegExpMacroAssembler::kParamStartOffsetIndex,
Object::dynamic_type());
fn.SetParameterNameAt(RegExpMacroAssembler::kParamStartOffsetIndex,
Symbols::start_index_param());
signature.set_result_type(Type::Handle(zone, Type::ArrayType()));
// Cache the result.
regexp.set_function(specialization_cid, sticky, fn);
fn.SetRegExpData(regexp, specialization_cid, sticky);
fn.set_is_debuggable(false);
// The function is compiled lazily during the first call.
}
RegExpPtr RegExpEngine::CreateRegExp(Thread* thread,
const String& pattern,
RegExpFlags flags) {
Zone* zone = thread->zone();
const RegExp& regexp = RegExp::Handle(RegExp::New(zone));
regexp.set_pattern(pattern);
regexp.set_flags(flags);
// TODO(zerny): We might want to use normal string searching algorithms
// for simple patterns.
regexp.set_is_complex();
regexp.set_is_global(); // All dart regexps are global.
if (!FLAG_interpret_irregexp) {
const Library& lib = Library::Handle(zone, Library::CoreLibrary());
const Class& owner =
Class::Handle(zone, lib.LookupClass(Symbols::RegExp()));
for (intptr_t cid = kOneByteStringCid; cid <= kTwoByteStringCid; cid++) {
CreateSpecializedFunction(thread, zone, regexp, cid, /*sticky=*/false,
owner);
CreateSpecializedFunction(thread, zone, regexp, cid, /*sticky=*/true,
owner);
}
}
return regexp.ptr();
}
} // namespace dart