runtime/vm/regexp_assembler_bytecode.cc - sdk - Git at Google

 // Copyright (c) 2015, 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_assembler_bytecode.h"

 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/regexp.h"
 #include "vm/regexp_assembler.h"
 #include "vm/regexp_assembler_bytecode_inl.h"
 #include "vm/regexp_bytecodes.h"
 #include "vm/regexp_interpreter.h"
 #include "vm/regexp_parser.h"
 #include "vm/timeline.h"

 namespace dart {

 BytecodeRegExpMacroAssembler::BytecodeRegExpMacroAssembler(
     ZoneGrowableArray<uint8_t>* buffer,
     Zone* zone)
     : RegExpMacroAssembler(zone),
       buffer_(buffer),
       pc_(0),
       advance_current_end_(kInvalidPC) {}

 BytecodeRegExpMacroAssembler::~BytecodeRegExpMacroAssembler() {
   if (backtrack_.is_linked()) backtrack_.Unuse();
 }

 BytecodeRegExpMacroAssembler::IrregexpImplementation
 BytecodeRegExpMacroAssembler::Implementation() {
   return kBytecodeImplementation;
 }

 void BytecodeRegExpMacroAssembler::BindBlock(BlockLabel* l) {
   advance_current_end_ = kInvalidPC;
   ASSERT(!l->is_bound());
   if (l->is_linked()) {
     intptr_t pos = l->pos();
     while (pos != 0) {
       intptr_t fixup = pos;
       pos = *reinterpret_cast<int32_t*>(buffer_->data() + fixup);
       *reinterpret_cast<uint32_t*>(buffer_->data() + fixup) = pc_;
     }
   }
   l->BindTo(pc_);
 }

 void BytecodeRegExpMacroAssembler::EmitOrLink(BlockLabel* l) {
   if (l == NULL) l = &backtrack_;
   if (l->is_bound()) {
     Emit32(l->pos());
   } else {
     int pos = 0;
     if (l->is_linked()) {
       pos = l->pos();
     }
     l->LinkTo(pc_);
     Emit32(pos);
   }
 }

 void BytecodeRegExpMacroAssembler::PopRegister(intptr_t register_index) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_POP_REGISTER, register_index);
 }

 void BytecodeRegExpMacroAssembler::PushRegister(intptr_t register_index) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_PUSH_REGISTER, register_index);
 }

 void BytecodeRegExpMacroAssembler::WriteCurrentPositionToRegister(
     intptr_t register_index,
     intptr_t cp_offset) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_SET_REGISTER_TO_CP, register_index);
   Emit32(cp_offset);  // Current position offset.
 }

 void BytecodeRegExpMacroAssembler::ClearRegisters(intptr_t reg_from,
                                                   intptr_t reg_to) {
   ASSERT(reg_from <= reg_to);
   for (int reg = reg_from; reg <= reg_to; reg++) {
     SetRegister(reg, -1);
   }
 }

 void BytecodeRegExpMacroAssembler::ReadCurrentPositionFromRegister(
     intptr_t register_index) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_SET_CP_TO_REGISTER, register_index);
 }

 void BytecodeRegExpMacroAssembler::WriteStackPointerToRegister(
     intptr_t register_index) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_SET_REGISTER_TO_SP, register_index);
 }

 void BytecodeRegExpMacroAssembler::ReadStackPointerFromRegister(
     intptr_t register_index) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_SET_SP_TO_REGISTER, register_index);
 }

 void BytecodeRegExpMacroAssembler::SetCurrentPositionFromEnd(intptr_t by) {
   ASSERT(Utils::IsUint(24, by));
   Emit(BC_SET_CURRENT_POSITION_FROM_END, by);
 }

 void BytecodeRegExpMacroAssembler::SetRegister(intptr_t register_index,
                                                intptr_t to) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_SET_REGISTER, register_index);
   Emit32(to);
 }

 void BytecodeRegExpMacroAssembler::AdvanceRegister(intptr_t register_index,
                                                    intptr_t by) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_ADVANCE_REGISTER, register_index);
   Emit32(by);
 }

 void BytecodeRegExpMacroAssembler::PopCurrentPosition() {
   Emit(BC_POP_CP, 0);
 }

 void BytecodeRegExpMacroAssembler::PushCurrentPosition() {
   Emit(BC_PUSH_CP, 0);
 }

 void BytecodeRegExpMacroAssembler::Backtrack() {
   Emit(BC_POP_BT, 0);
 }

 void BytecodeRegExpMacroAssembler::GoTo(BlockLabel* l) {
   if (advance_current_end_ == pc_) {
     // Combine advance current and goto.
     pc_ = advance_current_start_;
     Emit(BC_ADVANCE_CP_AND_GOTO, advance_current_offset_);
     EmitOrLink(l);
     advance_current_end_ = kInvalidPC;
   } else {
     // Regular goto.
     Emit(BC_GOTO, 0);
     EmitOrLink(l);
   }
 }

 void BytecodeRegExpMacroAssembler::PushBacktrack(BlockLabel* l) {
   Emit(BC_PUSH_BT, 0);
   EmitOrLink(l);
 }

 bool BytecodeRegExpMacroAssembler::Succeed() {
   Emit(BC_SUCCEED, 0);
   return false;  // Restart matching for global regexp not supported.
 }

 void BytecodeRegExpMacroAssembler::Fail() {
   Emit(BC_FAIL, 0);
 }

 void BytecodeRegExpMacroAssembler::AdvanceCurrentPosition(intptr_t by) {
   ASSERT(by >= kMinCPOffset);
   ASSERT(by <= kMaxCPOffset);
   advance_current_start_ = pc_;
   advance_current_offset_ = by;
   Emit(BC_ADVANCE_CP, by);
   advance_current_end_ = pc_;
 }

 void BytecodeRegExpMacroAssembler::CheckGreedyLoop(
     BlockLabel* on_tos_equals_current_position) {
   Emit(BC_CHECK_GREEDY, 0);
   EmitOrLink(on_tos_equals_current_position);
 }

 void BytecodeRegExpMacroAssembler::LoadCurrentCharacter(intptr_t cp_offset,
                                                         BlockLabel* on_failure,
                                                         bool check_bounds,
                                                         intptr_t characters) {
   ASSERT(cp_offset >= kMinCPOffset);
   ASSERT(cp_offset <= kMaxCPOffset);
   int bytecode;
   if (check_bounds) {
     if (characters == 4) {
       bytecode = BC_LOAD_4_CURRENT_CHARS;
     } else if (characters == 2) {
       bytecode = BC_LOAD_2_CURRENT_CHARS;
     } else {
       ASSERT(characters == 1);
       bytecode = BC_LOAD_CURRENT_CHAR;
     }
   } else {
     if (characters == 4) {
       bytecode = BC_LOAD_4_CURRENT_CHARS_UNCHECKED;
     } else if (characters == 2) {
       bytecode = BC_LOAD_2_CURRENT_CHARS_UNCHECKED;
     } else {
       ASSERT(characters == 1);
       bytecode = BC_LOAD_CURRENT_CHAR_UNCHECKED;
     }
   }
   Emit(bytecode, cp_offset);
   if (check_bounds) EmitOrLink(on_failure);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacterLT(uint16_t limit,
                                                     BlockLabel* on_less) {
   Emit(BC_CHECK_LT, limit);
   EmitOrLink(on_less);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacterGT(uint16_t limit,
                                                     BlockLabel* on_greater) {
   Emit(BC_CHECK_GT, limit);
   EmitOrLink(on_greater);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacter(uint32_t c,
                                                   BlockLabel* on_equal) {
   if (c > MAX_FIRST_ARG) {
     Emit(BC_CHECK_4_CHARS, 0);
     Emit32(c);
   } else {
     Emit(BC_CHECK_CHAR, c);
   }
   EmitOrLink(on_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckAtStart(BlockLabel* on_at_start) {
   Emit(BC_CHECK_AT_START, 0);
   EmitOrLink(on_at_start);
 }

 void BytecodeRegExpMacroAssembler::CheckNotAtStart(
     intptr_t cp_offset,
     BlockLabel* on_not_at_start) {
   Emit(BC_CHECK_NOT_AT_START, cp_offset);
   EmitOrLink(on_not_at_start);
 }

 void BytecodeRegExpMacroAssembler::CheckNotCharacter(uint32_t c,
                                                      BlockLabel* on_not_equal) {
   if (c > MAX_FIRST_ARG) {
     Emit(BC_CHECK_NOT_4_CHARS, 0);
     Emit32(c);
   } else {
     Emit(BC_CHECK_NOT_CHAR, c);
   }
   EmitOrLink(on_not_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacterAfterAnd(
     uint32_t c,
     uint32_t mask,
     BlockLabel* on_equal) {
   if (c > MAX_FIRST_ARG) {
     Emit(BC_AND_CHECK_4_CHARS, 0);
     Emit32(c);
   } else {
     Emit(BC_AND_CHECK_CHAR, c);
   }
   Emit32(mask);
   EmitOrLink(on_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckNotCharacterAfterAnd(
     uint32_t c,
     uint32_t mask,
     BlockLabel* on_not_equal) {
   if (c > MAX_FIRST_ARG) {
     Emit(BC_AND_CHECK_NOT_4_CHARS, 0);
     Emit32(c);
   } else {
     Emit(BC_AND_CHECK_NOT_CHAR, c);
   }
   Emit32(mask);
   EmitOrLink(on_not_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckNotCharacterAfterMinusAnd(
     uint16_t c,
     uint16_t minus,
     uint16_t mask,
     BlockLabel* on_not_equal) {
   Emit(BC_MINUS_AND_CHECK_NOT_CHAR, c);
   Emit16(minus);
   Emit16(mask);
   EmitOrLink(on_not_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacterInRange(
     uint16_t from,
     uint16_t to,
     BlockLabel* on_in_range) {
   Emit(BC_CHECK_CHAR_IN_RANGE, 0);
   Emit16(from);
   Emit16(to);
   EmitOrLink(on_in_range);
 }

 void BytecodeRegExpMacroAssembler::CheckCharacterNotInRange(
     uint16_t from,
     uint16_t to,
     BlockLabel* on_not_in_range) {
   Emit(BC_CHECK_CHAR_NOT_IN_RANGE, 0);
   Emit16(from);
   Emit16(to);
   EmitOrLink(on_not_in_range);
 }

 void BytecodeRegExpMacroAssembler::CheckBitInTable(const TypedData& table,
                                                    BlockLabel* on_bit_set) {
   Emit(BC_CHECK_BIT_IN_TABLE, 0);
   EmitOrLink(on_bit_set);
   for (int i = 0; i < kTableSize; i += kBitsPerByte) {
     int byte = 0;
     for (int j = 0; j < kBitsPerByte; j++) {
       if (table.GetUint8(i + j) != 0) byte |= 1 << j;
     }
     Emit8(byte);
   }
 }

 void BytecodeRegExpMacroAssembler::CheckNotBackReference(
     intptr_t start_reg,
     bool read_backward,
     BlockLabel* on_not_equal) {
   ASSERT(start_reg >= 0);
   ASSERT(start_reg <= kMaxRegister);
   Emit(read_backward ? BC_CHECK_NOT_BACK_REF_BACKWARD : BC_CHECK_NOT_BACK_REF,
        start_reg);
   EmitOrLink(on_not_equal);
 }

 void BytecodeRegExpMacroAssembler::CheckNotBackReferenceIgnoreCase(
     intptr_t start_reg,
     bool read_backward,
     bool unicode,
     BlockLabel* on_not_equal) {
   ASSERT(start_reg >= 0);
   ASSERT(start_reg <= kMaxRegister);
   Emit(read_backward ? (unicode ? BC_CHECK_NOT_BACK_REF_NO_CASE_UNICODE_BACKWARD
                                 : BC_CHECK_NOT_BACK_REF_NO_CASE_BACKWARD)
                      : (unicode ? BC_CHECK_NOT_BACK_REF_NO_CASE_UNICODE
                                 : BC_CHECK_NOT_BACK_REF_NO_CASE),
        start_reg);
   EmitOrLink(on_not_equal);
 }

 void BytecodeRegExpMacroAssembler::IfRegisterLT(intptr_t register_index,
                                                 intptr_t comparand,
                                                 BlockLabel* on_less_than) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_CHECK_REGISTER_LT, register_index);
   Emit32(comparand);
   EmitOrLink(on_less_than);
 }

 void BytecodeRegExpMacroAssembler::IfRegisterGE(
     intptr_t register_index,
     intptr_t comparand,
     BlockLabel* on_greater_or_equal) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_CHECK_REGISTER_GE, register_index);
   Emit32(comparand);
   EmitOrLink(on_greater_or_equal);
 }

 void BytecodeRegExpMacroAssembler::IfRegisterEqPos(intptr_t register_index,
                                                    BlockLabel* on_eq) {
   ASSERT(register_index >= 0);
   ASSERT(register_index <= kMaxRegister);
   Emit(BC_CHECK_REGISTER_EQ_POS, register_index);
   EmitOrLink(on_eq);
 }

 TypedDataPtr BytecodeRegExpMacroAssembler::GetBytecode() {
   BindBlock(&backtrack_);
   Emit(BC_POP_BT, 0);

   intptr_t len = length();
   const TypedData& bytecode =
       TypedData::Handle(TypedData::New(kTypedDataUint8ArrayCid, len));

   NoSafepointScope no_safepoint;
   memmove(bytecode.DataAddr(0), buffer_->data(), len);

   return bytecode.ptr();
 }

 intptr_t BytecodeRegExpMacroAssembler::length() {
   return pc_;
 }

 void BytecodeRegExpMacroAssembler::Expand() {
   // BOGUS
   buffer_->Add(0);
   buffer_->Add(0);
   buffer_->Add(0);
   buffer_->Add(0);
   intptr_t x = buffer_->length();
   for (intptr_t i = 0; i < x; i++)
     buffer_->Add(0);
 }

 static intptr_t Prepare(const RegExp& regexp,
                         const String& subject,
                         bool sticky,
                         Zone* zone) {
   bool is_one_byte =
       subject.IsOneByteString() || subject.IsExternalOneByteString();

   if (regexp.bytecode(is_one_byte, sticky) == TypedData::null()) {
     const String& pattern = String::Handle(zone, regexp.pattern());
 #if defined(SUPPORT_TIMELINE)
     TimelineBeginEndScope tbes(Thread::Current(), Timeline::GetCompilerStream(),
                                "CompileIrregexpBytecode");
     if (tbes.enabled()) {
       tbes.SetNumArguments(1);
       tbes.CopyArgument(0, "pattern", pattern.ToCString());
     }
 #endif  // !defined(PRODUCT)

     RegExpCompileData* compile_data = new (zone) RegExpCompileData();

     // Parsing failures are handled in the RegExp factory constructor.
     RegExpParser::ParseRegExp(pattern, regexp.flags(), compile_data);

     regexp.set_num_bracket_expressions(compile_data->capture_count);
     regexp.set_capture_name_map(compile_data->capture_name_map);
     if (compile_data->simple) {
       regexp.set_is_simple();
     } else {
       regexp.set_is_complex();
     }

     RegExpEngine::CompilationResult result = RegExpEngine::CompileBytecode(
         compile_data, regexp, is_one_byte, sticky, zone);
     if (result.error_message != nullptr) {
       Exceptions::ThrowUnsupportedError(result.error_message);
     }
     ASSERT(result.bytecode != NULL);
     ASSERT(regexp.num_registers(is_one_byte) == -1 ||
            regexp.num_registers(is_one_byte) == result.num_registers);
     regexp.set_num_registers(is_one_byte, result.num_registers);
     regexp.set_bytecode(is_one_byte, sticky, *(result.bytecode));
   }

   ASSERT(regexp.num_registers(is_one_byte) != -1);

   return regexp.num_registers(is_one_byte) +
          (regexp.num_bracket_expressions() + 1) * 2;
 }

 static ObjectPtr ExecRaw(const RegExp& regexp,
                          const String& subject,
                          intptr_t index,
                          bool sticky,
                          int32_t* output,
                          intptr_t output_size,
                          Zone* zone) {
   bool is_one_byte =
       subject.IsOneByteString() || subject.IsExternalOneByteString();

   // We must have done EnsureCompiledIrregexp, so we can get the number of
   // registers.
   int number_of_capture_registers = (regexp.num_bracket_expressions() + 1) * 2;
   int32_t* raw_output = &output[number_of_capture_registers];

   // We do not touch the actual capture result registers until we know there
   // has been a match so that we can use those capture results to set the
   // last match info.
   for (int i = number_of_capture_registers - 1; i >= 0; i--) {
     raw_output[i] = -1;
   }

   const TypedData& bytecode =
       TypedData::Handle(zone, regexp.bytecode(is_one_byte, sticky));
   ASSERT(!bytecode.IsNull());
   const Object& result = Object::Handle(
       zone, IrregexpInterpreter::Match(bytecode, subject, raw_output, index));

   if (result.ptr() == Bool::True().ptr()) {
     // Copy capture results to the start of the registers array.
     memmove(output, raw_output, number_of_capture_registers * sizeof(int32_t));
   }
   if (result.ptr() == Object::null()) {
     // Exception during regexp processing
     Exceptions::ThrowStackOverflow();
     UNREACHABLE();
   }
   return result.ptr();
 }

 ObjectPtr BytecodeRegExpMacroAssembler::Interpret(const RegExp& regexp,
                                                   const String& subject,
                                                   const Smi& start_index,
                                                   bool sticky,
                                                   Zone* zone) {
   intptr_t required_registers = Prepare(regexp, subject, sticky, zone);
   if (required_registers < 0) {
     // Compiling failed with an exception.
     UNREACHABLE();
   }

   // V8 uses a shared copy on the isolate when smaller than some threshold.
   int32_t* output_registers = zone->Alloc<int32_t>(required_registers);

   const Object& result =
       Object::Handle(zone, ExecRaw(regexp, subject, start_index.Value(), sticky,
                                    output_registers, required_registers, zone));
   if (result.ptr() == Bool::True().ptr()) {
     intptr_t capture_count = regexp.num_bracket_expressions();
     intptr_t capture_register_count = (capture_count + 1) * 2;
     ASSERT(required_registers >= capture_register_count);

     const TypedData& result = TypedData::Handle(
         TypedData::New(kTypedDataInt32ArrayCid, capture_register_count));
     {
 #ifdef DEBUG
       // These indices will be used with substring operations that don't check
       // bounds, so sanity check them here.
       for (intptr_t i = 0; i < capture_register_count; i++) {
         int32_t val = output_registers[i];
         ASSERT(val == -1 || (val >= 0 && val <= subject.Length()));
       }
 #endif

       NoSafepointScope no_safepoint;
       memmove(result.DataAddr(0), output_registers,
               capture_register_count * sizeof(int32_t));
     }

     return result.ptr();
   }
   if (result.ptr() == Object::null()) {
     // internal exception
     UNREACHABLE();
   }
   if (result.IsError()) {
     Exceptions::PropagateError(Error::Cast(result));
     UNREACHABLE();
   }
   ASSERT(result.ptr() == Bool::False().ptr());
   return Instance::null();
 }

 }  // namespace dart
	// Copyright (c) 2015, 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_assembler_bytecode.h"

	#include "vm/exceptions.h"
	#include "vm/object_store.h"
	#include "vm/regexp.h"
	#include "vm/regexp_assembler.h"
	#include "vm/regexp_assembler_bytecode_inl.h"
	#include "vm/regexp_bytecodes.h"
	#include "vm/regexp_interpreter.h"
	#include "vm/regexp_parser.h"
	#include "vm/timeline.h"

	namespace dart {

	BytecodeRegExpMacroAssembler::BytecodeRegExpMacroAssembler(
	ZoneGrowableArray<uint8_t>* buffer,
	Zone* zone)
	: RegExpMacroAssembler(zone),
	buffer_(buffer),
	pc_(0),
	advance_current_end_(kInvalidPC) {}

	BytecodeRegExpMacroAssembler::~BytecodeRegExpMacroAssembler() {
	if (backtrack_.is_linked()) backtrack_.Unuse();
	}

	BytecodeRegExpMacroAssembler::IrregexpImplementation
	BytecodeRegExpMacroAssembler::Implementation() {
	return kBytecodeImplementation;
	}

	void BytecodeRegExpMacroAssembler::BindBlock(BlockLabel* l) {
	advance_current_end_ = kInvalidPC;
	ASSERT(!l->is_bound());
	if (l->is_linked()) {
	intptr_t pos = l->pos();
	while (pos != 0) {
	intptr_t fixup = pos;
	pos = reinterpret_cast<int32_t>(buffer_->data() + fixup);
	reinterpret_cast<uint32_t>(buffer_->data() + fixup) = pc_;
	}
	}
	l->BindTo(pc_);
	}

	void BytecodeRegExpMacroAssembler::EmitOrLink(BlockLabel* l) {
	if (l == NULL) l = &backtrack_;
	if (l->is_bound()) {
	Emit32(l->pos());
	} else {
	int pos = 0;
	if (l->is_linked()) {
	pos = l->pos();
	}
	l->LinkTo(pc_);
	Emit32(pos);
	}
	}

	void BytecodeRegExpMacroAssembler::PopRegister(intptr_t register_index) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_POP_REGISTER, register_index);
	}

	void BytecodeRegExpMacroAssembler::PushRegister(intptr_t register_index) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_PUSH_REGISTER, register_index);
	}

	void BytecodeRegExpMacroAssembler::WriteCurrentPositionToRegister(
	intptr_t register_index,
	intptr_t cp_offset) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_SET_REGISTER_TO_CP, register_index);
	Emit32(cp_offset); // Current position offset.
	}

	void BytecodeRegExpMacroAssembler::ClearRegisters(intptr_t reg_from,
	intptr_t reg_to) {
	ASSERT(reg_from <= reg_to);
	for (int reg = reg_from; reg <= reg_to; reg++) {
	SetRegister(reg, -1);
	}
	}

	void BytecodeRegExpMacroAssembler::ReadCurrentPositionFromRegister(
	intptr_t register_index) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_SET_CP_TO_REGISTER, register_index);
	}

	void BytecodeRegExpMacroAssembler::WriteStackPointerToRegister(
	intptr_t register_index) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_SET_REGISTER_TO_SP, register_index);
	}

	void BytecodeRegExpMacroAssembler::ReadStackPointerFromRegister(
	intptr_t register_index) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_SET_SP_TO_REGISTER, register_index);
	}

	void BytecodeRegExpMacroAssembler::SetCurrentPositionFromEnd(intptr_t by) {
	ASSERT(Utils::IsUint(24, by));
	Emit(BC_SET_CURRENT_POSITION_FROM_END, by);
	}

	void BytecodeRegExpMacroAssembler::SetRegister(intptr_t register_index,
	intptr_t to) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_SET_REGISTER, register_index);
	Emit32(to);
	}

	void BytecodeRegExpMacroAssembler::AdvanceRegister(intptr_t register_index,
	intptr_t by) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_ADVANCE_REGISTER, register_index);
	Emit32(by);
	}

	void BytecodeRegExpMacroAssembler::PopCurrentPosition() {
	Emit(BC_POP_CP, 0);
	}

	void BytecodeRegExpMacroAssembler::PushCurrentPosition() {
	Emit(BC_PUSH_CP, 0);
	}

	void BytecodeRegExpMacroAssembler::Backtrack() {
	Emit(BC_POP_BT, 0);
	}

	void BytecodeRegExpMacroAssembler::GoTo(BlockLabel* l) {
	if (advance_current_end_ == pc_) {
	// Combine advance current and goto.
	pc_ = advance_current_start_;
	Emit(BC_ADVANCE_CP_AND_GOTO, advance_current_offset_);
	EmitOrLink(l);
	advance_current_end_ = kInvalidPC;
	} else {
	// Regular goto.
	Emit(BC_GOTO, 0);
	EmitOrLink(l);
	}
	}

	void BytecodeRegExpMacroAssembler::PushBacktrack(BlockLabel* l) {
	Emit(BC_PUSH_BT, 0);
	EmitOrLink(l);
	}

	bool BytecodeRegExpMacroAssembler::Succeed() {
	Emit(BC_SUCCEED, 0);
	return false; // Restart matching for global regexp not supported.
	}

	void BytecodeRegExpMacroAssembler::Fail() {
	Emit(BC_FAIL, 0);
	}

	void BytecodeRegExpMacroAssembler::AdvanceCurrentPosition(intptr_t by) {
	ASSERT(by >= kMinCPOffset);
	ASSERT(by <= kMaxCPOffset);
	advance_current_start_ = pc_;
	advance_current_offset_ = by;
	Emit(BC_ADVANCE_CP, by);
	advance_current_end_ = pc_;
	}

	void BytecodeRegExpMacroAssembler::CheckGreedyLoop(
	BlockLabel* on_tos_equals_current_position) {
	Emit(BC_CHECK_GREEDY, 0);
	EmitOrLink(on_tos_equals_current_position);
	}

	void BytecodeRegExpMacroAssembler::LoadCurrentCharacter(intptr_t cp_offset,
	BlockLabel* on_failure,
	bool check_bounds,
	intptr_t characters) {
	ASSERT(cp_offset >= kMinCPOffset);
	ASSERT(cp_offset <= kMaxCPOffset);
	int bytecode;
	if (check_bounds) {
	if (characters == 4) {
	bytecode = BC_LOAD_4_CURRENT_CHARS;
	} else if (characters == 2) {
	bytecode = BC_LOAD_2_CURRENT_CHARS;
	} else {
	ASSERT(characters == 1);
	bytecode = BC_LOAD_CURRENT_CHAR;
	}
	} else {
	if (characters == 4) {
	bytecode = BC_LOAD_4_CURRENT_CHARS_UNCHECKED;
	} else if (characters == 2) {
	bytecode = BC_LOAD_2_CURRENT_CHARS_UNCHECKED;
	} else {
	ASSERT(characters == 1);
	bytecode = BC_LOAD_CURRENT_CHAR_UNCHECKED;
	}
	}
	Emit(bytecode, cp_offset);
	if (check_bounds) EmitOrLink(on_failure);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacterLT(uint16_t limit,
	BlockLabel* on_less) {
	Emit(BC_CHECK_LT, limit);
	EmitOrLink(on_less);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacterGT(uint16_t limit,
	BlockLabel* on_greater) {
	Emit(BC_CHECK_GT, limit);
	EmitOrLink(on_greater);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacter(uint32_t c,
	BlockLabel* on_equal) {
	if (c > MAX_FIRST_ARG) {
	Emit(BC_CHECK_4_CHARS, 0);
	Emit32(c);
	} else {
	Emit(BC_CHECK_CHAR, c);
	}
	EmitOrLink(on_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckAtStart(BlockLabel* on_at_start) {
	Emit(BC_CHECK_AT_START, 0);
	EmitOrLink(on_at_start);
	}

	void BytecodeRegExpMacroAssembler::CheckNotAtStart(
	intptr_t cp_offset,
	BlockLabel* on_not_at_start) {
	Emit(BC_CHECK_NOT_AT_START, cp_offset);
	EmitOrLink(on_not_at_start);
	}

	void BytecodeRegExpMacroAssembler::CheckNotCharacter(uint32_t c,
	BlockLabel* on_not_equal) {
	if (c > MAX_FIRST_ARG) {
	Emit(BC_CHECK_NOT_4_CHARS, 0);
	Emit32(c);
	} else {
	Emit(BC_CHECK_NOT_CHAR, c);
	}
	EmitOrLink(on_not_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacterAfterAnd(
	uint32_t c,
	uint32_t mask,
	BlockLabel* on_equal) {
	if (c > MAX_FIRST_ARG) {
	Emit(BC_AND_CHECK_4_CHARS, 0);
	Emit32(c);
	} else {
	Emit(BC_AND_CHECK_CHAR, c);
	}
	Emit32(mask);
	EmitOrLink(on_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckNotCharacterAfterAnd(
	uint32_t c,
	uint32_t mask,
	BlockLabel* on_not_equal) {
	if (c > MAX_FIRST_ARG) {
	Emit(BC_AND_CHECK_NOT_4_CHARS, 0);
	Emit32(c);
	} else {
	Emit(BC_AND_CHECK_NOT_CHAR, c);
	}
	Emit32(mask);
	EmitOrLink(on_not_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckNotCharacterAfterMinusAnd(
	uint16_t c,
	uint16_t minus,
	uint16_t mask,
	BlockLabel* on_not_equal) {
	Emit(BC_MINUS_AND_CHECK_NOT_CHAR, c);
	Emit16(minus);
	Emit16(mask);
	EmitOrLink(on_not_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacterInRange(
	uint16_t from,
	uint16_t to,
	BlockLabel* on_in_range) {
	Emit(BC_CHECK_CHAR_IN_RANGE, 0);
	Emit16(from);
	Emit16(to);
	EmitOrLink(on_in_range);
	}

	void BytecodeRegExpMacroAssembler::CheckCharacterNotInRange(
	uint16_t from,
	uint16_t to,
	BlockLabel* on_not_in_range) {
	Emit(BC_CHECK_CHAR_NOT_IN_RANGE, 0);
	Emit16(from);
	Emit16(to);
	EmitOrLink(on_not_in_range);
	}

	void BytecodeRegExpMacroAssembler::CheckBitInTable(const TypedData& table,
	BlockLabel* on_bit_set) {
	Emit(BC_CHECK_BIT_IN_TABLE, 0);
	EmitOrLink(on_bit_set);
	for (int i = 0; i < kTableSize; i += kBitsPerByte) {
	int byte = 0;
	for (int j = 0; j < kBitsPerByte; j++) {
	if (table.GetUint8(i + j) != 0) byte \|= 1 << j;
	}
	Emit8(byte);
	}
	}

	void BytecodeRegExpMacroAssembler::CheckNotBackReference(
	intptr_t start_reg,
	bool read_backward,
	BlockLabel* on_not_equal) {
	ASSERT(start_reg >= 0);
	ASSERT(start_reg <= kMaxRegister);
	Emit(read_backward ? BC_CHECK_NOT_BACK_REF_BACKWARD : BC_CHECK_NOT_BACK_REF,
	start_reg);
	EmitOrLink(on_not_equal);
	}

	void BytecodeRegExpMacroAssembler::CheckNotBackReferenceIgnoreCase(
	intptr_t start_reg,
	bool read_backward,
	bool unicode,
	BlockLabel* on_not_equal) {
	ASSERT(start_reg >= 0);
	ASSERT(start_reg <= kMaxRegister);
	Emit(read_backward ? (unicode ? BC_CHECK_NOT_BACK_REF_NO_CASE_UNICODE_BACKWARD
	: BC_CHECK_NOT_BACK_REF_NO_CASE_BACKWARD)
	: (unicode ? BC_CHECK_NOT_BACK_REF_NO_CASE_UNICODE
	: BC_CHECK_NOT_BACK_REF_NO_CASE),
	start_reg);
	EmitOrLink(on_not_equal);
	}

	void BytecodeRegExpMacroAssembler::IfRegisterLT(intptr_t register_index,
	intptr_t comparand,
	BlockLabel* on_less_than) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_CHECK_REGISTER_LT, register_index);
	Emit32(comparand);
	EmitOrLink(on_less_than);
	}

	void BytecodeRegExpMacroAssembler::IfRegisterGE(
	intptr_t register_index,
	intptr_t comparand,
	BlockLabel* on_greater_or_equal) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_CHECK_REGISTER_GE, register_index);
	Emit32(comparand);
	EmitOrLink(on_greater_or_equal);
	}

	void BytecodeRegExpMacroAssembler::IfRegisterEqPos(intptr_t register_index,
	BlockLabel* on_eq) {
	ASSERT(register_index >= 0);
	ASSERT(register_index <= kMaxRegister);
	Emit(BC_CHECK_REGISTER_EQ_POS, register_index);
	EmitOrLink(on_eq);
	}

	TypedDataPtr BytecodeRegExpMacroAssembler::GetBytecode() {
	BindBlock(&backtrack_);
	Emit(BC_POP_BT, 0);

	intptr_t len = length();
	const TypedData& bytecode =
	TypedData::Handle(TypedData::New(kTypedDataUint8ArrayCid, len));

	NoSafepointScope no_safepoint;
	memmove(bytecode.DataAddr(0), buffer_->data(), len);

	return bytecode.ptr();
	}

	intptr_t BytecodeRegExpMacroAssembler::length() {
	return pc_;
	}

	void BytecodeRegExpMacroAssembler::Expand() {
	// BOGUS
	buffer_->Add(0);
	buffer_->Add(0);
	buffer_->Add(0);
	buffer_->Add(0);
	intptr_t x = buffer_->length();
	for (intptr_t i = 0; i < x; i++)
	buffer_->Add(0);
	}

	static intptr_t Prepare(const RegExp& regexp,
	const String& subject,
	bool sticky,
	Zone* zone) {
	bool is_one_byte =
	subject.IsOneByteString() \|\| subject.IsExternalOneByteString();

	if (regexp.bytecode(is_one_byte, sticky) == TypedData::null()) {
	const String& pattern = String::Handle(zone, regexp.pattern());
	#if defined(SUPPORT_TIMELINE)
	TimelineBeginEndScope tbes(Thread::Current(), Timeline::GetCompilerStream(),
	"CompileIrregexpBytecode");
	if (tbes.enabled()) {
	tbes.SetNumArguments(1);
	tbes.CopyArgument(0, "pattern", pattern.ToCString());
	}
	#endif // !defined(PRODUCT)

	RegExpCompileData* compile_data = new (zone) RegExpCompileData();

	// Parsing failures are handled in the RegExp factory constructor.
	RegExpParser::ParseRegExp(pattern, regexp.flags(), compile_data);

	regexp.set_num_bracket_expressions(compile_data->capture_count);
	regexp.set_capture_name_map(compile_data->capture_name_map);
	if (compile_data->simple) {
	regexp.set_is_simple();
	} else {
	regexp.set_is_complex();
	}

	RegExpEngine::CompilationResult result = RegExpEngine::CompileBytecode(
	compile_data, regexp, is_one_byte, sticky, zone);
	if (result.error_message != nullptr) {
	Exceptions::ThrowUnsupportedError(result.error_message);
	}
	ASSERT(result.bytecode != NULL);
	ASSERT(regexp.num_registers(is_one_byte) == -1 \|\|
	regexp.num_registers(is_one_byte) == result.num_registers);
	regexp.set_num_registers(is_one_byte, result.num_registers);
	regexp.set_bytecode(is_one_byte, sticky, *(result.bytecode));
	}

	ASSERT(regexp.num_registers(is_one_byte) != -1);

	return regexp.num_registers(is_one_byte) +
	(regexp.num_bracket_expressions() + 1) * 2;
	}

	static ObjectPtr ExecRaw(const RegExp& regexp,
	const String& subject,
	intptr_t index,
	bool sticky,
	int32_t* output,
	intptr_t output_size,
	Zone* zone) {
	bool is_one_byte =
	subject.IsOneByteString() \|\| subject.IsExternalOneByteString();

	// We must have done EnsureCompiledIrregexp, so we can get the number of
	// registers.
	int number_of_capture_registers = (regexp.num_bracket_expressions() + 1) * 2;
	int32_t* raw_output = &output[number_of_capture_registers];

	// We do not touch the actual capture result registers until we know there
	// has been a match so that we can use those capture results to set the
	// last match info.
	for (int i = number_of_capture_registers - 1; i >= 0; i--) {
	raw_output[i] = -1;
	}

	const TypedData& bytecode =
	TypedData::Handle(zone, regexp.bytecode(is_one_byte, sticky));
	ASSERT(!bytecode.IsNull());
	const Object& result = Object::Handle(
	zone, IrregexpInterpreter::Match(bytecode, subject, raw_output, index));

	if (result.ptr() == Bool::True().ptr()) {
	// Copy capture results to the start of the registers array.
	memmove(output, raw_output, number_of_capture_registers * sizeof(int32_t));
	}
	if (result.ptr() == Object::null()) {
	// Exception during regexp processing
	Exceptions::ThrowStackOverflow();
	UNREACHABLE();
	}
	return result.ptr();
	}

	ObjectPtr BytecodeRegExpMacroAssembler::Interpret(const RegExp& regexp,
	const String& subject,
	const Smi& start_index,
	bool sticky,
	Zone* zone) {
	intptr_t required_registers = Prepare(regexp, subject, sticky, zone);
	if (required_registers < 0) {
	// Compiling failed with an exception.
	UNREACHABLE();
	}

	// V8 uses a shared copy on the isolate when smaller than some threshold.
	int32_t* output_registers = zone->Alloc<int32_t>(required_registers);

	const Object& result =
	Object::Handle(zone, ExecRaw(regexp, subject, start_index.Value(), sticky,
	output_registers, required_registers, zone));
	if (result.ptr() == Bool::True().ptr()) {
	intptr_t capture_count = regexp.num_bracket_expressions();
	intptr_t capture_register_count = (capture_count + 1) * 2;
	ASSERT(required_registers >= capture_register_count);

	const TypedData& result = TypedData::Handle(
	TypedData::New(kTypedDataInt32ArrayCid, capture_register_count));
	{
	#ifdef DEBUG
	// These indices will be used with substring operations that don't check
	// bounds, so sanity check them here.
	for (intptr_t i = 0; i < capture_register_count; i++) {
	int32_t val = output_registers[i];
	ASSERT(val == -1 \|\| (val >= 0 && val <= subject.Length()));
	}
	#endif

	NoSafepointScope no_safepoint;
	memmove(result.DataAddr(0), output_registers,
	capture_register_count * sizeof(int32_t));
	}

	return result.ptr();
	}
	if (result.ptr() == Object::null()) {
	// internal exception
	UNREACHABLE();
	}
	if (result.IsError()) {
	Exceptions::PropagateError(Error::Cast(result));
	UNREACHABLE();
	}
	ASSERT(result.ptr() == Bool::False().ptr());
	return Instance::null();
	}

	} // namespace dart