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dart / sdk.git / refs/tags/2.18.0-53.0.dev / . / runtime / vm / type_testing_stubs.cc
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// Copyright (c) 2018, 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 <functional>
#include "platform/globals.h"
#include "vm/class_id.h"
#include "vm/compiler/assembler/disassembler.h"
#include "vm/compiler/runtime_api.h"
#include "vm/hash_map.h"
#include "vm/longjump.h"
#include "vm/object_store.h"
#include "vm/stub_code.h"
#include "vm/timeline.h"
#include "vm/type_testing_stubs.h"
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/compiler/backend/flow_graph_compiler.h"
#include "vm/compiler/backend/il_printer.h"
#endif // !defined(DART_PRECOMPILED_RUNTIME)
#define __ assembler->
namespace dart {
TypeTestingStubNamer::TypeTestingStubNamer()
: lib_(Library::Handle()),
klass_(Class::Handle()),
type_(AbstractType::Handle()),
string_(String::Handle()) {}
const char* TypeTestingStubNamer::StubNameForType(
const AbstractType& type) const {
Zone* Z = Thread::Current()->zone();
return OS::SCreate(Z, "TypeTestingStub_%s", StringifyType(type));
}
const char* TypeTestingStubNamer::StringifyType(
const AbstractType& type) const {
NoSafepointScope no_safepoint;
Zone* Z = Thread::Current()->zone();
if (type.IsType()) {
const intptr_t cid = Type::Cast(type).type_class_id();
ClassTable* class_table = IsolateGroup::Current()->class_table();
klass_ = class_table->At(cid);
ASSERT(!klass_.IsNull());
const char* curl = "";
lib_ = klass_.library();
if (!lib_.IsNull()) {
string_ = lib_.url();
curl = OS::SCreate(Z, "%s_", string_.ToCString());
} else {
static std::atomic<intptr_t> counter = 0;
curl = OS::SCreate(Z, "nolib%" Pd "_", counter++);
}
const char* concatenated = AssemblerSafeName(
OS::SCreate(Z, "%s_%s", curl, klass_.ScrubbedNameCString()));
const intptr_t type_parameters = klass_.NumTypeParameters();
auto& type_arguments = TypeArguments::Handle();
if (type.arguments() != TypeArguments::null() && type_parameters > 0) {
type_arguments = type.arguments();
ASSERT(type_arguments.Length() >= type_parameters);
const intptr_t length = type_arguments.Length();
for (intptr_t i = 0; i < type_parameters; ++i) {
type_ = type_arguments.TypeAt(length - type_parameters + i);
concatenated =
OS::SCreate(Z, "%s__%s", concatenated, StringifyType(type_));
}
}
return concatenated;
} else if (type.IsTypeParameter()) {
return AssemblerSafeName(
OS::SCreate(Z, "%s", TypeParameter::Cast(type).CanonicalNameCString()));
} else {
return AssemblerSafeName(OS::SCreate(Z, "%s", type.ToCString()));
}
}
const char* TypeTestingStubNamer::AssemblerSafeName(char* cname) {
char* cursor = cname;
while (*cursor != '\0') {
char c = *cursor;
if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') || (c == '_'))) {
*cursor = '_';
}
cursor++;
}
return cname;
}
CodePtr TypeTestingStubGenerator::DefaultCodeForType(
const AbstractType& type,
bool lazy_specialize /* = true */) {
auto isolate_group = IsolateGroup::Current();
if (type.IsTypeRef()) {
return isolate_group->use_strict_null_safety_checks()
? StubCode::DefaultTypeTest().ptr()
: StubCode::DefaultNullableTypeTest().ptr();
}
// During bootstrapping we have no access to stubs yet, so we'll just return
// `null` and patch these later in `Object::FinishInit()`.
if (!StubCode::HasBeenInitialized()) {
ASSERT(type.IsType());
const classid_t cid = type.type_class_id();
ASSERT(cid == kDynamicCid || cid == kVoidCid);
return Code::null();
}
if (type.IsTopTypeForSubtyping()) {
return StubCode::TopTypeTypeTest().ptr();
}
if (type.IsTypeParameter()) {
const bool nullable = Instance::NullIsAssignableTo(type);
if (nullable) {
return StubCode::NullableTypeParameterTypeTest().ptr();
} else {
return StubCode::TypeParameterTypeTest().ptr();
}
}
if (type.IsFunctionType()) {
const bool nullable = Instance::NullIsAssignableTo(type);
return nullable ? StubCode::DefaultNullableTypeTest().ptr()
: StubCode::DefaultTypeTest().ptr();
}
if (type.IsType()) {
const bool should_specialize = !FLAG_precompiled_mode && lazy_specialize;
const bool nullable = Instance::NullIsAssignableTo(type);
if (should_specialize) {
return nullable ? StubCode::LazySpecializeNullableTypeTest().ptr()
: StubCode::LazySpecializeTypeTest().ptr();
} else {
return nullable ? StubCode::DefaultNullableTypeTest().ptr()
: StubCode::DefaultTypeTest().ptr();
}
}
return StubCode::UnreachableTypeTest().ptr();
}
#if !defined(DART_PRECOMPILED_RUNTIME)
CodePtr TypeTestingStubGenerator::SpecializeStubFor(Thread* thread,
const AbstractType& type) {
HierarchyInfo hi(thread);
TypeTestingStubGenerator generator;
return generator.OptimizedCodeForType(type);
}
#endif
TypeTestingStubGenerator::TypeTestingStubGenerator()
: object_store_(IsolateGroup::Current()->object_store()) {}
CodePtr TypeTestingStubGenerator::OptimizedCodeForType(
const AbstractType& type) {
#if !defined(TARGET_ARCH_IA32)
ASSERT(StubCode::HasBeenInitialized());
if (type.IsTypeRef() || type.IsTypeParameter()) {
return TypeTestingStubGenerator::DefaultCodeForType(
type, /*lazy_specialize=*/false);
}
if (type.IsTopTypeForSubtyping()) {
return StubCode::TopTypeTypeTest().ptr();
}
if (type.IsCanonical()) {
if (type.IsType()) {
#if !defined(DART_PRECOMPILED_RUNTIME)
const Code& code = Code::Handle(
TypeTestingStubGenerator::BuildCodeForType(Type::Cast(type)));
if (!code.IsNull()) {
return code.ptr();
}
const Error& error = Error::Handle(Thread::Current()->StealStickyError());
if (!error.IsNull()) {
if (error.ptr() == Object::out_of_memory_error().ptr()) {
Exceptions::ThrowOOM();
} else {
UNREACHABLE();
}
}
// Fall back to default.
#else
// In the precompiled runtime we cannot lazily create new optimized type
// testing stubs, so if we cannot find one, we'll just return the default
// one.
#endif // !defined(DART_PRECOMPILED_RUNTIME)
}
}
#endif // !defined(TARGET_ARCH_IA32)
return TypeTestingStubGenerator::DefaultCodeForType(
type, /*lazy_specialize=*/false);
}
#if !defined(TARGET_ARCH_IA32)
#if !defined(DART_PRECOMPILED_RUNTIME)
static CodePtr RetryCompilationWithFarBranches(
Thread* thread,
std::function<CodePtr(compiler::Assembler&)> fun) {
volatile intptr_t far_branch_level = 0;
while (true) {
LongJumpScope jump;
if (setjmp(*jump.Set()) == 0) {
// To use the already-defined __ Macro !
compiler::Assembler assembler(nullptr, far_branch_level);
return fun(assembler);
} else {
// We bailed out or we encountered an error.
const Error& error = Error::Handle(thread->StealStickyError());
if (error.ptr() == Object::branch_offset_error().ptr()) {
ASSERT(far_branch_level < 2);
far_branch_level++;
} else if (error.ptr() == Object::out_of_memory_error().ptr()) {
thread->set_sticky_error(error);
return Code::null();
} else {
UNREACHABLE();
}
}
}
}
CodePtr TypeTestingStubGenerator::BuildCodeForType(const Type& type) {
auto thread = Thread::Current();
auto zone = thread->zone();
HierarchyInfo* hi = thread->hierarchy_info();
ASSERT(hi != NULL);
if (!hi->CanUseSubtypeRangeCheckFor(type) &&
!hi->CanUseGenericSubtypeRangeCheckFor(type)) {
return Code::null();
}
const Class& type_class = Class::Handle(type.type_class());
ASSERT(!type_class.IsNull());
auto& slow_tts_stub = Code::ZoneHandle(zone);
if (FLAG_precompiled_mode) {
slow_tts_stub = thread->isolate_group()->object_store()->slow_tts_stub();
}
const Code& code = Code::Handle(
thread->zone(),
RetryCompilationWithFarBranches(
thread, [&](compiler::Assembler& assembler) {
compiler::UnresolvedPcRelativeCalls unresolved_calls;
BuildOptimizedTypeTestStub(&assembler, &unresolved_calls,
slow_tts_stub, hi, type, type_class);
const auto& static_calls_table = Array::Handle(
zone, compiler::StubCodeCompiler::BuildStaticCallsTable(
zone, &unresolved_calls));
const char* name = namer_.StubNameForType(type);
const auto pool_attachment =
FLAG_precompiled_mode ? Code::PoolAttachment::kNotAttachPool
: Code::PoolAttachment::kAttachPool;
Code& code = Code::Handle(thread->zone());
auto install_code_fun = [&]() {
code = Code::FinalizeCode(nullptr, &assembler, pool_attachment,
/*optimized=*/false, /*stats=*/nullptr);
if (!static_calls_table.IsNull()) {
code.set_static_calls_target_table(static_calls_table);
}
};
// We have to ensure no mutators are running, because:
//
// a) We allocate an instructions object, which might cause us to
// temporarily flip page protections from (RX -> RW -> RX).
//
SafepointWriteRwLocker ml(thread,
thread->isolate_group()->program_lock());
thread->isolate_group()->RunWithStoppedMutators(
install_code_fun,
/*use_force_growth=*/true);
Code::NotifyCodeObservers(name, code, /*optimized=*/false);
code.set_owner(type);
#ifndef PRODUCT
if (FLAG_support_disassembler && FLAG_disassemble_stubs) {
LogBlock lb;
THR_Print("Code for stub '%s' (type = %s): {\n", name,
type.ToCString());
DisassembleToStdout formatter;
code.Disassemble(&formatter);
THR_Print("}\n");
const ObjectPool& object_pool =
ObjectPool::Handle(code.object_pool());
if (!object_pool.IsNull()) {
object_pool.DebugPrint();
}
}
#endif // !PRODUCT
return code.ptr();
}));
return code.ptr();
}
void TypeTestingStubGenerator::BuildOptimizedTypeTestStub(
compiler::Assembler* assembler,
compiler::UnresolvedPcRelativeCalls* unresolved_calls,
const Code& slow_type_test_stub,
HierarchyInfo* hi,
const Type& type,
const Class& type_class) {
BuildOptimizedTypeTestStubFastCases(assembler, hi, type, type_class);
__ Jump(compiler::Address(
THR, compiler::target::Thread::slow_type_test_entry_point_offset()));
}
void TypeTestingStubGenerator::BuildOptimizedTypeTestStubFastCases(
compiler::Assembler* assembler,
HierarchyInfo* hi,
const Type& type,
const Class& type_class) {
// These are handled via the TopTypeTypeTestStub!
ASSERT(!type.IsTopTypeForSubtyping());
if (type.IsObjectType()) {
ASSERT(type.IsNonNullable() &&
hi->thread()->isolate_group()->use_strict_null_safety_checks());
compiler::Label is_null;
__ CompareObject(TypeTestABI::kInstanceReg, Object::null_object());
__ BranchIf(EQUAL, &is_null, compiler::Assembler::kNearJump);
__ Ret();
__ Bind(&is_null);
return; // No further checks needed.
}
// Fast case for 'int' and '_Smi' (which can appear in core libraries).
if (type.IsIntType() || type.IsSmiType()) {
compiler::Label non_smi_value;
__ BranchIfNotSmi(TypeTestABI::kInstanceReg, &non_smi_value,
compiler::Assembler::kNearJump);
__ Ret();
__ Bind(&non_smi_value);
} else {
// TODO(kustermann): Make more fast cases, e.g. Type::Number()
// is implemented by Smi.
}
// Check the cid ranges which are a subtype of [type].
if (hi->CanUseSubtypeRangeCheckFor(type)) {
const CidRangeVector& ranges = hi->SubtypeRangesForClass(
type_class,
/*include_abstract=*/false,
/*exclude_null=*/!Instance::NullIsAssignableTo(type));
compiler::Label is_subtype, is_not_subtype;
const bool smi_is_ok =
Type::Handle(Type::SmiType()).IsSubtypeOf(type, Heap::kNew);
if (smi_is_ok) {
__ LoadClassIdMayBeSmi(TTSInternalRegs::kScratchReg,
TypeTestABI::kInstanceReg);
} else {
__ BranchIfSmi(TypeTestABI::kInstanceReg, &is_not_subtype);
__ LoadClassId(TTSInternalRegs::kScratchReg, TypeTestABI::kInstanceReg);
}
BuildOptimizedSubtypeRangeCheck(assembler, ranges,
TTSInternalRegs::kScratchReg, &is_subtype,
&is_not_subtype);
__ Bind(&is_subtype);
__ Ret();
__ Bind(&is_not_subtype);
} else {
BuildOptimizedSubclassRangeCheckWithTypeArguments(assembler, hi, type,
type_class);
}
if (Instance::NullIsAssignableTo(type)) {
// Fast case for 'null'.
compiler::Label non_null;
__ CompareObject(TypeTestABI::kInstanceReg, Object::null_object());
__ BranchIf(NOT_EQUAL, &non_null, compiler::Assembler::kNearJump);
__ Ret();
__ Bind(&non_null);
}
}
static void CommentCheckedClasses(compiler::Assembler* assembler,
const CidRangeVector& ranges) {
if (!assembler->EmittingComments()) return;
Thread* const thread = Thread::Current();
ClassTable* const class_table = thread->isolate_group()->class_table();
Zone* const zone = thread->zone();
if (ranges.is_empty()) {
__ Comment("No valid cids to check");
return;
}
if ((ranges.length() == 1) && ranges[0].IsSingleCid()) {
const auto& cls = Class::Handle(zone, class_table->At(ranges[0].cid_start));
__ Comment("Checking for cid %" Pd " (%s)", cls.id(),
cls.ScrubbedNameCString());
return;
}
__ Comment("Checking for concrete finalized classes:");
auto& cls = Class::Handle(zone);
for (const auto& range : ranges) {
ASSERT(!range.IsIllegalRange());
for (classid_t cid = range.cid_start; cid <= range.cid_end; cid++) {
// Invalid entries can be included to keep range count low.
if (!class_table->HasValidClassAt(cid)) continue;
cls = class_table->At(cid);
if (cls.is_abstract()) continue; // Only output concrete classes.
__ Comment(" * %" Pd32 " (%s)", cid, cls.ScrubbedNameCString());
}
}
}
// Represents the following needs for runtime checks to see if an instance of
// [cls] is a subtype of [type] that has type class [type_class]:
//
// * kCannotBeChecked: Instances of [cls] cannot be checked with any of the
// currently implemented runtime checks, so must fall back on the runtime.
//
// * kNotSubtype: A [cls] instance is guaranteed to not be a subtype of [type]
// regardless of any instance type arguments.
//
// * kCidCheckOnly: A [cls] instance is guaranteed to be a subtype of [type]
// regardless of any instance type arguments.
//
// * kNeedsFinalization: Checking that an instance of [cls] is a subtype of
// [type] requires instance type arguments, but [cls] is not finalized, and
// so the appropriate type arguments field offset cannot be determined.
//
// * kInstanceTypeArgumentsAreSubtypes: [cls] implements a fully uninstantiated
// type with type class [type_class] which can be directly instantiated with
// the instance type arguments. Thus, each type argument of [type] should be
// compared with the corresponding (index-wise) instance type argument.
enum class CheckType {
kCannotBeChecked,
kNotSubtype,
kCidCheckOnly,
kNeedsFinalization,
kInstanceTypeArgumentsAreSubtypes,
};
// Returns a CheckType describing how to check instances of [to_check] as
// subtypes of [type].
static CheckType SubtypeChecksForClass(Zone* zone,
const Type& type,
const Class& type_class,
const Class& to_check) {
ASSERT_EQUAL(type.type_class_id(), type_class.id());
ASSERT(type_class.is_type_finalized());
ASSERT(!to_check.is_abstract());
ASSERT(to_check.is_type_finalized());
ASSERT(AbstractType::Handle(zone, to_check.RareType())
.IsSubtypeOf(AbstractType::Handle(zone, type_class.RareType()),
Heap::kNew));
if (!type_class.IsGeneric()) {
// All instances of [to_check] are subtypes of [type].
return CheckType::kCidCheckOnly;
}
if (to_check.FindInstantiationOf(zone, type_class,
/*only_super_classes=*/true)) {
// No need to check for type argument consistency, as [to_check] is the same
// as or a subclass of [type_class].
return to_check.is_finalized()
? CheckType::kInstanceTypeArgumentsAreSubtypes
: CheckType::kCannotBeChecked;
}
auto& calculated_type =
AbstractType::Handle(zone, to_check.GetInstantiationOf(zone, type_class));
if (calculated_type.IsInstantiated()) {
if (type.IsInstantiated()) {
return calculated_type.IsSubtypeOf(type, Heap::kNew)
? CheckType::kCidCheckOnly
: CheckType::kNotSubtype;
}
// TODO(dartbug.com/46920): Requires walking both types, checking
// corresponding instantiated parts at compile time (assuming uninstantiated
// parts check successfully) and then creating appropriate runtime checks
// for uninstantiated parts of [type].
return CheckType::kCannotBeChecked;
}
if (!to_check.is_finalized()) {
return CheckType::kNeedsFinalization;
}
ASSERT(to_check.NumTypeArguments() > 0);
ASSERT(compiler::target::Class::TypeArgumentsFieldOffset(to_check) !=
compiler::target::Class::kNoTypeArguments);
// If the calculated type arguments are a prefix of the declaration type
// arguments, then we can just treat the instance type arguments as if they
// were used to instantiate the type class during checking.
const auto& decl_type_args = TypeArguments::Handle(
zone, Type::Handle(zone, to_check.DeclarationType()).arguments());
const auto& calculated_type_args =
TypeArguments::Handle(zone, calculated_type.arguments());
const bool type_args_consistent = calculated_type_args.IsSubvectorEquivalent(
decl_type_args, 0, type_class.NumTypeArguments(),
TypeEquality::kCanonical);
// TODO(dartbug.com/46920): Currently we require subtyping to be checkable
// by comparing the instance type arguments against the type arguments of
// [type] piecewise, but we could check other cases as well.
return type_args_consistent ? CheckType::kInstanceTypeArgumentsAreSubtypes
: CheckType::kCannotBeChecked;
}
static void CommentSkippedClasses(compiler::Assembler* assembler,
const Type& type,
const Class& type_class,
const CidRangeVector& ranges) {
if (!assembler->EmittingComments() || ranges.is_empty()) return;
if (ranges.is_empty()) return;
ASSERT(type_class.is_implemented());
__ Comment("Not checking the following concrete implementors of %s:",
type_class.ScrubbedNameCString());
Thread* const thread = Thread::Current();
auto* const class_table = thread->isolate_group()->class_table();
Zone* const zone = thread->zone();
auto& cls = Class::Handle(zone);
auto& calculated_type = Type::Handle(zone);
for (const auto& range : ranges) {
ASSERT(!range.IsIllegalRange());
for (classid_t cid = range.cid_start; cid <= range.cid_end; cid++) {
// Invalid entries can be included to keep range count low.
if (!class_table->HasValidClassAt(cid)) continue;
cls = class_table->At(cid);
if (cls.is_abstract()) continue; // Only output concrete classes.
ASSERT(cls.is_type_finalized());
TextBuffer buffer(128);
buffer.Printf(" * %" Pd32 "(%s): ", cid, cls.ScrubbedNameCString());
switch (SubtypeChecksForClass(zone, type, type_class, cls)) {
case CheckType::kCannotBeChecked:
calculated_type = cls.GetInstantiationOf(zone, type_class);
buffer.AddString("cannot check that ");
calculated_type.PrintName(Object::kScrubbedName, &buffer);
buffer.AddString(" is a subtype of ");
type.PrintName(Object::kScrubbedName, &buffer);
break;
case CheckType::kNotSubtype:
calculated_type = cls.GetInstantiationOf(zone, type_class);
calculated_type.PrintName(Object::kScrubbedName, &buffer);
buffer.AddString(" is not a subtype of ");
type.PrintName(Object::kScrubbedName, &buffer);
break;
case CheckType::kNeedsFinalization:
buffer.AddString("is not finalized");
break;
case CheckType::kInstanceTypeArgumentsAreSubtypes:
buffer.AddString("was not finalized during class splitting");
break;
default:
// Either the CheckType was kCidCheckOnly, which should never happen
// since it only requires type finalization, or a new CheckType has
// been added.
UNREACHABLE();
break;
}
__ Comment("%s", buffer.buffer());
}
}
}
// Builds a cid range check for the concrete subclasses and implementors of
// type. Falls through or jumps to check_succeeded if the range contains the
// cid, else jumps to check_failed.
//
// Returns whether class_id_reg is clobbered.
bool TypeTestingStubGenerator::BuildOptimizedSubtypeRangeCheck(
compiler::Assembler* assembler,
const CidRangeVector& ranges,
Register class_id_reg,
compiler::Label* check_succeeded,
compiler::Label* check_failed) {
CommentCheckedClasses(assembler, ranges);
return FlowGraphCompiler::GenerateCidRangesCheck(
assembler, class_id_reg, ranges, check_succeeded, check_failed, true);
}
void TypeTestingStubGenerator::
BuildOptimizedSubclassRangeCheckWithTypeArguments(
compiler::Assembler* assembler,
HierarchyInfo* hi,
const Type& type,
const Class& type_class) {
ASSERT(hi->CanUseGenericSubtypeRangeCheckFor(type));
compiler::Label check_failed, load_succeeded;
// a) First we perform subtype cid-range checks and load the instance type
// arguments based on which check succeeded.
if (BuildLoadInstanceTypeArguments(assembler, hi, type, type_class,
TTSInternalRegs::kScratchReg,
TTSInternalRegs::kInstanceTypeArgumentsReg,
&load_succeeded, &check_failed)) {
// Only build type argument checking if any checked cid ranges require it.
__ Bind(&load_succeeded);
// b) We check for "rare" types, where the instance type arguments are null.
//
// The kernel frontend should fill in any non-assigned type parameters on
// construction with dynamic/Object, so we should never get the null type
// argument vector in created instances.
//
// TODO(kustermann): We could consider not using "null" as type argument
// vector representing all-dynamic to avoid this extra check (which will be
// uncommon because most Dart code in 2.0 will be strongly typed)!
__ CompareObject(TTSInternalRegs::kInstanceTypeArgumentsReg,
Object::null_object());
const Type& rare_type = Type::Handle(Type::RawCast(type_class.RareType()));
if (rare_type.IsSubtypeOf(type, Heap::kNew)) {
compiler::Label process_done;
__ BranchIf(NOT_EQUAL, &process_done, compiler::Assembler::kNearJump);
__ Ret();
__ Bind(&process_done);
} else {
__ BranchIf(EQUAL, &check_failed);
}
// c) Then we'll check each value of the type argument.
compiler::Label pop_saved_registers_on_failure;
const RegisterSet saved_registers(
TTSInternalRegs::kSavedTypeArgumentRegisters);
__ PushRegisters(saved_registers);
AbstractType& type_arg = AbstractType::Handle();
const TypeArguments& ta = TypeArguments::Handle(type.arguments());
const intptr_t num_type_parameters = type_class.NumTypeParameters();
const intptr_t num_type_arguments = type_class.NumTypeArguments();
ASSERT(ta.Length() >= num_type_arguments);
for (intptr_t i = 0; i < num_type_parameters; ++i) {
const intptr_t type_param_value_offset_i =
num_type_arguments - num_type_parameters + i;
type_arg = ta.TypeAt(type_param_value_offset_i);
ASSERT(type_arg.IsTypeParameter() ||
hi->CanUseSubtypeRangeCheckFor(type_arg));
if (type_arg.IsTypeParameter()) {
BuildOptimizedTypeParameterArgumentValueCheck(
assembler, hi, TypeParameter::Cast(type_arg),
type_param_value_offset_i, &pop_saved_registers_on_failure);
} else {
BuildOptimizedTypeArgumentValueCheck(
assembler, hi, Type::Cast(type_arg), type_param_value_offset_i,
&pop_saved_registers_on_failure);
}
}
__ PopRegisters(saved_registers);
__ Ret();
__ Bind(&pop_saved_registers_on_failure);
__ PopRegisters(saved_registers);
}
// If anything fails.
__ Bind(&check_failed);
}
// Splits [ranges] into multiple ranges in [output], where the concrete,
// finalized classes in each range share the same type arguments field offset.
//
// The first range in [output] contains [type_class], if any do, and otherwise
// prioritizes ranges that include predefined cids before ranges that only
// contain user-defined classes.
//
// Any cids that do not have valid class table entries, correspond to abstract
// or unfinalized classes, or have no TAV field offset are treated as don't
// cares, in that the cid may appear in any of the CidRangeVectors as needed to
// reduce the number of ranges.
//
// Note that CidRangeVectors are MallocGrowableArrays, so the elements in
// output must be freed after use!
static void SplitByTypeArgumentsFieldOffset(
Thread* T,
const Class& type_class,
const CidRangeVector& ranges,
GrowableArray<CidRangeVector*>* output) {
ASSERT(output != nullptr);
ASSERT(!ranges.is_empty());
Zone* const Z = T->zone();
ClassTable* const class_table = T->isolate_group()->class_table();
IntMap<CidRangeVector*> offset_map(Z);
IntMap<intptr_t> predefined_offsets(Z);
IntMap<intptr_t> user_defined_offsets(Z);
auto add_to_vector = [&](intptr_t tav_offset, const CidRange& range) {
if (range.cid_start == -1) return;
ASSERT(tav_offset != compiler::target::Class::kNoTypeArguments);
if (CidRangeVector* vector = offset_map.Lookup(tav_offset)) {
vector->Add(range);
} else {
vector = new CidRangeVector(1);
vector->Add(range);
offset_map.Insert(tav_offset, vector);
}
};
auto increment_count = [&](intptr_t cid, intptr_t tav_offset) {
if (cid <= kNumPredefinedCids) {
predefined_offsets.Update(
{tav_offset, predefined_offsets.Lookup(tav_offset) + 1});
} else if (auto* const kv = predefined_offsets.LookupPair(tav_offset)) {
predefined_offsets.Update({kv->key, kv->value + 1});
} else {
user_defined_offsets.Update(
{tav_offset, user_defined_offsets.Lookup(tav_offset) + 1});
}
};
// First populate offset_map.
auto& cls = Class::Handle(Z);
for (const auto& range : ranges) {
intptr_t last_offset = compiler::target::Class::kNoTypeArguments;
intptr_t cid_start = -1;
intptr_t cid_end = -1;
for (intptr_t cid = range.cid_start; cid <= range.cid_end; cid++) {
if (!class_table->HasValidClassAt(cid)) continue;
cls = class_table->At(cid);
if (cls.is_abstract()) continue;
// Only finalized concrete classes are present due to the conditions on
// returning kInstanceTypeArgumentsAreSubtypes in SubtypeChecksForClass.
ASSERT(cls.is_finalized());
const intptr_t tav_offset =
compiler::target::Class::TypeArgumentsFieldOffset(cls);
if (tav_offset == compiler::target::Class::kNoTypeArguments) continue;
if (tav_offset == last_offset && cid_start >= 0) {
cid_end = cid;
increment_count(cid, tav_offset);
continue;
}
add_to_vector(last_offset, {cid_start, cid_end});
last_offset = tav_offset;
cid_start = cid_end = cid;
increment_count(cid, tav_offset);
}
add_to_vector(last_offset, {cid_start, cid_end});
}
ASSERT(!offset_map.IsEmpty());
// Add the CidRangeVector for the type_class's offset, if it has one.
if (!type_class.is_abstract() && type_class.is_finalized()) {
const intptr_t type_class_offset =
compiler::target::Class::TypeArgumentsFieldOffset(type_class);
ASSERT(predefined_offsets.LookupPair(type_class_offset) != nullptr ||
user_defined_offsets.LookupPair(type_class_offset) != nullptr);
CidRangeVector* const vector = offset_map.Lookup(type_class_offset);
ASSERT(vector != nullptr);
output->Add(vector);
// Remove this CidRangeVector from consideration in the following loops.
predefined_offsets.Remove(type_class_offset);
user_defined_offsets.Remove(type_class_offset);
}
// Now add CidRangeVectors that include predefined cids.
// For now, we do this in an arbitrary order, but we could use the counts
// to prioritize offsets that are more shared if desired.
auto predefined_it = predefined_offsets.GetIterator();
while (auto* const kv = predefined_it.Next()) {
CidRangeVector* const vector = offset_map.Lookup(kv->key);
ASSERT(vector != nullptr);
output->Add(vector);
}
// Finally, add CidRangeVectors that only include user-defined cids.
// For now, we do this in an arbitrary order, but we could use the counts
// to prioritize offsets that are more shared if desired.
auto user_defined_it = user_defined_offsets.GetIterator();
while (auto* const kv = user_defined_it.Next()) {
CidRangeVector* const vector = offset_map.Lookup(kv->key);
ASSERT(vector != nullptr);
output->Add(vector);
}
ASSERT(output->length() > 0);
}
// Given [type], its type class [type_class], and a CidRangeVector [ranges],
// populates the output CidRangeVectors from cids in [ranges], based on what
// runtime checks are needed to determine whether the runtime type of
// an instance is a subtype of [type].
//
// Concrete, type finalized classes whose cids are added to [cid_check_only]
// implement a particular instantiation of [type_class] that is guaranteed to
// be a subtype of [type]. Thus, these instances do not require any checking
// of type arguments.
//
// Concrete, finalized classes whose cids are added to [type_argument_checks]
// implement a fully uninstantiated version of [type_class] that can be directly
// instantiated with the type arguments of the class's instance. Thus, each
// type argument of [type] should be checked against the corresponding
// instance type argument.
//
// Classes whose cids are in [not_checked]:
// * Instances of the class are guaranteed to not be a subtype of [type].
// * The class is not finalized.
// * The subtype relation cannot be checked with our current approach and
// thus the stub must fall back to the STC/VM runtime.
//
// Any cids that do not have valid class table entries or correspond to
// abstract classes are treated as don't cares, in that the cid may or may not
// appear as needed to reduce the number of ranges.
static void SplitOnTypeArgumentTests(HierarchyInfo* hi,
const Type& type,
const Class& type_class,
const CidRangeVector& ranges,
CidRangeVector* cid_check_only,
CidRangeVector* type_argument_checks,
CidRangeVector* not_checked) {
ASSERT(type_class.is_implemented()); // No need to split if not implemented.
ASSERT(cid_check_only->is_empty());
ASSERT(type_argument_checks->is_empty());
ASSERT(not_checked->is_empty());
ClassTable* const class_table = hi->thread()->isolate_group()->class_table();
Zone* const zone = hi->thread()->zone();
auto& to_check = Class::Handle(zone);
auto add_cid_range = [&](CheckType check, const CidRange& range) {
if (range.cid_start == -1) return;
switch (check) {
case CheckType::kCidCheckOnly:
cid_check_only->Add(range);
break;
case CheckType::kInstanceTypeArgumentsAreSubtypes:
type_argument_checks->Add(range);
break;
default:
not_checked->Add(range);
}
};
for (const auto& range : ranges) {
CheckType last_check = CheckType::kCannotBeChecked;
classid_t cid_start = -1, cid_end = -1;
for (classid_t cid = range.cid_start; cid <= range.cid_end; cid++) {
// Invalid entries can be included to keep range count low.
if (!class_table->HasValidClassAt(cid)) continue;
to_check = class_table->At(cid);
if (to_check.is_abstract()) continue;
const CheckType current_check =
SubtypeChecksForClass(zone, type, type_class, to_check);
ASSERT(current_check != CheckType::kInstanceTypeArgumentsAreSubtypes ||
to_check.is_finalized());
if (last_check == current_check && cid_start >= 0) {
cid_end = cid;
continue;
}
add_cid_range(last_check, {cid_start, cid_end});
last_check = current_check;
cid_start = cid_end = cid;
}
add_cid_range(last_check, {cid_start, cid_end});
}
}
bool TypeTestingStubGenerator::BuildLoadInstanceTypeArguments(
compiler::Assembler* assembler,
HierarchyInfo* hi,
const Type& type,
const Class& type_class,
const Register class_id_reg,
const Register instance_type_args_reg,
compiler::Label* load_succeeded,
compiler::Label* load_failed) {
const CidRangeVector& ranges =
hi->SubtypeRangesForClass(type_class, /*include_abstract=*/false,
!Instance::NullIsAssignableTo(type));
if (ranges.is_empty()) {
// Fall through and signal type argument checks should not be generated.
CommentCheckedClasses(assembler, ranges);
return false;
}
if (!type_class.is_implemented()) {
ASSERT(type_class.is_finalized());
const intptr_t tav_offset =
compiler::target::Class::TypeArgumentsFieldOffset(type_class);
compiler::Label is_subtype;
__ LoadClassIdMayBeSmi(class_id_reg, TypeTestABI::kInstanceReg);
BuildOptimizedSubtypeRangeCheck(assembler, ranges, class_id_reg,
&is_subtype, load_failed);
__ Bind(&is_subtype);
if (tav_offset != compiler::target::Class::kNoTypeArguments) {
// The class and its subclasses have trivially consistent type arguments.
__ LoadCompressedFieldFromOffset(instance_type_args_reg,
TypeTestABI::kInstanceReg, tav_offset);
return true;
} else {
// Not a generic type, so cid checks are sufficient.
__ Ret();
return false;
}
}
Thread* const T = hi->thread();
Zone* const Z = T->zone();
CidRangeVector cid_checks_only, type_argument_checks, not_checked;
SplitOnTypeArgumentTests(hi, type, type_class, ranges, &cid_checks_only,
&type_argument_checks, &not_checked);
ASSERT(!CidRangeVectorUtils::ContainsCid(type_argument_checks, kSmiCid));
const bool smi_valid =
CidRangeVectorUtils::ContainsCid(cid_checks_only, kSmiCid);
// If we'll generate any cid checks and Smi isn't a valid subtype, then
// do a single Smi check here, since each generated check requires a fresh
// load of the class id. Otherwise, we'll generate the Smi check as part of
// the cid checks only block.
if (!smi_valid &&
(!cid_checks_only.is_empty() || !type_argument_checks.is_empty())) {
__ BranchIfSmi(TypeTestABI::kInstanceReg, load_failed);
}
// Ensure that if the cid checks only block is skipped, the first iteration
// of the type arguments check will generate a cid load.
bool cid_needs_reload = true;
if (!cid_checks_only.is_empty()) {
compiler::Label is_subtype, keep_looking;
compiler::Label* check_failed =
type_argument_checks.is_empty() ? load_failed : &keep_looking;
if (smi_valid) {
__ LoadClassIdMayBeSmi(class_id_reg, TypeTestABI::kInstanceReg);
} else {
__ LoadClassId(class_id_reg, TypeTestABI::kInstanceReg);
}
cid_needs_reload = BuildOptimizedSubtypeRangeCheck(
assembler, cid_checks_only, class_id_reg, &is_subtype, check_failed);
__ Bind(&is_subtype);
__ Ret();
__ Bind(&keep_looking);
}
if (!type_argument_checks.is_empty()) {
GrowableArray<CidRangeVector*> vectors;
SplitByTypeArgumentsFieldOffset(T, type_class, type_argument_checks,
&vectors);
ASSERT(vectors.length() > 0);
ClassTable* const class_table = T->isolate_group()->class_table();
auto& cls = Class::Handle(Z);
for (intptr_t i = 0; i < vectors.length(); i++) {
CidRangeVector* const vector = vectors[i];
ASSERT(!vector->is_empty());
const intptr_t first_cid = vector->At(0).cid_start;
ASSERT(class_table->HasValidClassAt(first_cid));
cls = class_table->At(first_cid);
ASSERT(cls.is_finalized());
const intptr_t tav_offset =
compiler::target::Class::TypeArgumentsFieldOffset(cls);
compiler::Label load_tav, keep_looking;
// For the last vector, just jump to load_failed if the check fails
// and avoid emitting a jump to load_succeeded.
compiler::Label* check_failed =
i < vectors.length() - 1 ? &keep_looking : load_failed;
if (cid_needs_reload) {
__ LoadClassId(class_id_reg, TypeTestABI::kInstanceReg);
}
cid_needs_reload = BuildOptimizedSubtypeRangeCheck(
assembler, *vector, class_id_reg, &load_tav, check_failed);
__ Bind(&load_tav);
__ LoadCompressedFieldFromOffset(instance_type_args_reg,
TypeTestABI::kInstanceReg, tav_offset);
if (i < vectors.length() - 1) {
__ Jump(load_succeeded);
__ Bind(&keep_looking);
}
// Free the CidRangeVector allocated by SplitByTypeArgumentsFieldOffset.
delete vector;
}
}
if (!not_checked.is_empty()) {
CommentSkippedClasses(assembler, type, type_class, not_checked);
}
return !type_argument_checks.is_empty();
}
// Unwraps TypeRefs, jumping to the appropriate label for the unwrapped type
// if that label is not nullptr and otherwise falling through.
//
// [type_reg] must contain an AbstractTypePtr, and [scratch] must be distinct
// from [type_reg]. Clobbers [type_reg] with the unwrapped type.
static void UnwrapAbstractType(compiler::Assembler* assembler,
Register type_reg,
Register scratch,
compiler::Label* is_type = nullptr,
compiler::Label* is_function_type = nullptr,
compiler::Label* is_type_parameter = nullptr) {
ASSERT(scratch != type_reg);
compiler::Label cid_checks, fall_through;
// TypeRefs never wrap other TypeRefs, so we only need to unwrap once.
__ LoadClassId(scratch, type_reg);
__ CompareImmediate(scratch, kTypeRefCid);
__ BranchIf(NOT_EQUAL, &cid_checks, compiler::Assembler::kNearJump);
__ LoadCompressedFieldFromOffset(type_reg, type_reg,
compiler::target::TypeRef::type_offset());
// Only load the class id of the unwrapped type if it will be checked below.
if (is_type != nullptr || is_function_type != nullptr ||
is_type_parameter != nullptr) {
__ LoadClassId(scratch, type_reg);
}
__ Bind(&cid_checks);
if (is_type != nullptr) {
__ CompareImmediate(scratch, kTypeCid);
__ BranchIf(EQUAL, is_type);
}
if (is_function_type != nullptr) {
__ CompareImmediate(scratch, kFunctionTypeCid);
__ BranchIf(EQUAL, is_function_type);
}
if (is_type_parameter != nullptr) {
__ CompareImmediate(scratch, kTypeParameterCid);
__ BranchIf(EQUAL, is_type_parameter);
}
}
void TypeTestingStubGenerator::BuildOptimizedTypeParameterArgumentValueCheck(
compiler::Assembler* assembler,
HierarchyInfo* hi,
const TypeParameter& type_param,
intptr_t type_param_value_offset_i,
compiler::Label* check_failed) {
if (assembler->EmittingComments()) {
TextBuffer buffer(128);
buffer.Printf("Generating check for type argument %" Pd ": ",
type_param_value_offset_i);
type_param.PrintName(Object::kScrubbedName, &buffer);
__ Comment("%s", buffer.buffer());
}
const Register kTypeArgumentsReg =
type_param.IsClassTypeParameter()
? TypeTestABI::kInstantiatorTypeArgumentsReg
: TypeTestABI::kFunctionTypeArgumentsReg;
const bool strict_null_safety =
hi->thread()->isolate_group()->use_strict_null_safety_checks();
compiler::Label is_subtype;
// TODO(dartbug.com/46920): Currently only canonical equality (identity)
// and some top and bottom types are checked.
__ CompareObject(kTypeArgumentsReg, Object::null_object());
__ BranchIf(EQUAL, &is_subtype);
__ LoadCompressedFieldFromOffset(
TTSInternalRegs::kSuperTypeArgumentReg, kTypeArgumentsReg,
compiler::target::TypeArguments::type_at_offset(type_param.index()));
__ LoadCompressedFieldFromOffset(
TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kInstanceTypeArgumentsReg,
compiler::target::TypeArguments::type_at_offset(
type_param_value_offset_i));
__ CompareRegisters(TTSInternalRegs::kSuperTypeArgumentReg,
TTSInternalRegs::kSubTypeArgumentReg);
__ BranchIf(EQUAL, &is_subtype);
__ Comment("Checking instantiated type parameter for possible top types");
compiler::Label check_subtype_type_class_ids;
UnwrapAbstractType(assembler, TTSInternalRegs::kSuperTypeArgumentReg,
TTSInternalRegs::kScratchReg, /*is_type=*/nullptr,
&check_subtype_type_class_ids);
__ LoadTypeClassId(TTSInternalRegs::kScratchReg,
TTSInternalRegs::kSuperTypeArgumentReg);
__ CompareImmediate(TTSInternalRegs::kScratchReg, kDynamicCid);
__ BranchIf(EQUAL, &is_subtype);
__ CompareImmediate(TTSInternalRegs::kScratchReg, kVoidCid);
__ BranchIf(EQUAL, &is_subtype);
__ CompareImmediate(TTSInternalRegs::kScratchReg, kInstanceCid);
if (strict_null_safety) {
__ BranchIf(NOT_EQUAL, &check_subtype_type_class_ids);
// If non-nullable Object, then the subtype must be legacy or non-nullable.
__ CompareTypeNullabilityWith(
TTSInternalRegs::kSuperTypeArgumentReg,
static_cast<int8_t>(Nullability::kNonNullable));
__ BranchIf(NOT_EQUAL, &is_subtype);
__ Comment("Checking for legacy or non-nullable instance type argument");
compiler::Label subtype_is_type;
UnwrapAbstractType(assembler, TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kScratchReg, &subtype_is_type);
__ CompareFunctionTypeNullabilityWith(
TTSInternalRegs::kSubTypeArgumentReg,
static_cast<int8_t>(Nullability::kNullable));
__ BranchIf(EQUAL, check_failed);
__ Jump(&is_subtype);
__ Bind(&subtype_is_type);
__ CompareTypeNullabilityWith(TTSInternalRegs::kSubTypeArgumentReg,
static_cast<int8_t>(Nullability::kNullable));
__ BranchIf(EQUAL, check_failed);
__ Jump(&is_subtype);
} else {
__ BranchIf(EQUAL, &is_subtype, compiler::Assembler::kNearJump);
}
__ Bind(&check_subtype_type_class_ids);
__ Comment("Checking instance type argument for possible bottom types");
// Nothing else to check for non-Types, so fall back to the slow stub.
UnwrapAbstractType(assembler, TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kScratchReg, /*is_type=*/nullptr,
check_failed);
__ LoadTypeClassId(TTSInternalRegs::kScratchReg,
TTSInternalRegs::kSubTypeArgumentReg);
__ CompareImmediate(TTSInternalRegs::kScratchReg, kNeverCid);
__ BranchIf(EQUAL, &is_subtype);
__ CompareImmediate(TTSInternalRegs::kScratchReg, kNullCid);
// Last possible check, so fall back to slow stub on failure.
__ BranchIf(NOT_EQUAL, check_failed);
if (strict_null_safety) {
// Only nullable or legacy types can be a supertype of Null.
__ Comment("Checking for legacy or nullable instantiated type parameter");
compiler::Label supertype_is_type;
UnwrapAbstractType(assembler, TTSInternalRegs::kSuperTypeArgumentReg,
TTSInternalRegs::kScratchReg, &supertype_is_type);
__ CompareFunctionTypeNullabilityWith(
TTSInternalRegs::kSuperTypeArgumentReg,
static_cast<int8_t>(Nullability::kNonNullable));
__ BranchIf(EQUAL, check_failed);
__ Jump(&is_subtype, compiler::Assembler::kNearJump);
__ Bind(&supertype_is_type);
__ CompareTypeNullabilityWith(
TTSInternalRegs::kSuperTypeArgumentReg,
static_cast<int8_t>(Nullability::kNonNullable));
__ BranchIf(EQUAL, check_failed);
}
__ Bind(&is_subtype);
}
// Generate code to verify that instance's type argument is a subtype of
// 'type_arg'.
void TypeTestingStubGenerator::BuildOptimizedTypeArgumentValueCheck(
compiler::Assembler* assembler,
HierarchyInfo* hi,
const Type& type,
intptr_t type_param_value_offset_i,
compiler::Label* check_failed) {
ASSERT(type.IsInstantiated());
if (type.IsTopTypeForSubtyping()) {
return;
}
const bool strict_null_safety =
hi->thread()->isolate_group()->use_strict_null_safety_checks();
ASSERT(!type.IsObjectType() || (strict_null_safety && type.IsNonNullable()));
if (assembler->EmittingComments()) {
TextBuffer buffer(128);
buffer.Printf("Generating check for type argument %" Pd ": ",
type_param_value_offset_i);
type.PrintName(Object::kScrubbedName, &buffer);
__ Comment("%s", buffer.buffer());
}
compiler::Label is_subtype, check_subtype_cid, sub_is_function_type,
sub_is_type;
__ LoadCompressedFieldFromOffset(
TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kInstanceTypeArgumentsReg,
compiler::target::TypeArguments::type_at_offset(
type_param_value_offset_i));
__ Bind(&check_subtype_cid);
UnwrapAbstractType(assembler, TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kScratchReg, &sub_is_type);
__ Comment("Checks for FunctionType");
__ EnsureHasClassIdInDEBUG(kFunctionTypeCid,
TTSInternalRegs::kSubTypeArgumentReg,
TTSInternalRegs::kScratchReg);
if (type.IsObjectType() || type.IsDartFunctionType()) {
if (strict_null_safety && type.IsNonNullable()) {
// Nullable types cannot be a subtype of a non-nullable type.
__ CompareFunctionTypeNullabilityWith(
TTSInternalRegs::kSubTypeArgumentReg,
compiler::target::Nullability::kNullable);
__ BranchIf(EQUAL, check_failed);
}
// No further checks needed for non-nullable Object or Function.
__ Jump(&is_subtype, compiler::Assembler::kNearJump);
} else {
// _Closure <: Function, and T <: Function for any FunctionType T, but
// T </: _Closure, so we _don't_ want to fall back to cid tests. Instead,
// just let the STC/runtime handle any possible false negatives here.
__ Jump(check_failed);
}
__ Comment("Checks for Type");
__ Bind(&sub_is_type);
if (strict_null_safety && type.IsNonNullable()) {
// Nullable types cannot be a subtype of a non-nullable type in strict mode.
__ CompareTypeNullabilityWith(TTSInternalRegs::kSubTypeArgumentReg,
compiler::target::Nullability::kNullable);
__ BranchIf(EQUAL, check_failed);
// Fall through to bottom type checks.
}
// No further checks needed for non-nullable object.
if (!type.IsObjectType()) {
__ LoadTypeClassId(TTSInternalRegs::kScratchReg,
TTSInternalRegs::kSubTypeArgumentReg);
const bool null_is_assignable = Instance::NullIsAssignableTo(type);
// Check bottom types.
__ CompareImmediate(TTSInternalRegs::kScratchReg, kNeverCid);
__ BranchIf(EQUAL, &is_subtype);
if (null_is_assignable) {
__ CompareImmediate(TTSInternalRegs::kScratchReg, kNullCid);
__ BranchIf(EQUAL, &is_subtype);
}
// Not a bottom type, so check cid ranges.
const Class& type_class = Class::Handle(type.type_class());
const CidRangeVector& ranges =
hi->SubtypeRangesForClass(type_class,
/*include_abstract=*/true,
/*exclude_null=*/!null_is_assignable);
BuildOptimizedSubtypeRangeCheck(assembler, ranges,
TTSInternalRegs::kScratchReg, &is_subtype,
check_failed);
}
__ Bind(&is_subtype);
}
void RegisterTypeArgumentsUse(const Function& function,
TypeUsageInfo* type_usage_info,
const Class& klass,
Definition* type_arguments) {
// The [type_arguments] can, in the general case, be any kind of [Definition]
// but generally (in order of expected frequency)
//
// Case a)
// type_arguments <- Constant(#null)
// type_arguments <- Constant(#TypeArguments: [ ... ])
//
// Case b)
// type_arguments <- InstantiateTypeArguments(ita, fta, uta)
// (where uta may not be a constant non-null TypeArguments object)
//
// Case c)
// type_arguments <- LoadField(vx)
// type_arguments <- LoadField(vx T{_ABC})
// type_arguments <- LoadField(vx T{Type: class: '_ABC'})
//
// Case d, e)
// type_arguments <- LoadIndexedUnsafe(rbp[vx + 16]))
// type_arguments <- Parameter(0)
if (ConstantInstr* constant = type_arguments->AsConstant()) {
const Object& object = constant->value();
ASSERT(object.IsNull() || object.IsTypeArguments());
const TypeArguments& type_arguments =
TypeArguments::Handle(TypeArguments::RawCast(object.ptr()));
type_usage_info->UseTypeArgumentsInInstanceCreation(klass, type_arguments);
} else if (InstantiateTypeArgumentsInstr* instantiate =
type_arguments->AsInstantiateTypeArguments()) {
if (instantiate->type_arguments()->BindsToConstant() &&
!instantiate->type_arguments()->BoundConstant().IsNull()) {
const auto& ta =
TypeArguments::Cast(instantiate->type_arguments()->BoundConstant());
type_usage_info->UseTypeArgumentsInInstanceCreation(klass, ta);
}
} else if (LoadFieldInstr* load_field = type_arguments->AsLoadField()) {
Definition* instance = load_field->instance()->definition();
intptr_t cid = instance->Type()->ToNullableCid();
if (cid == kDynamicCid) {
// This is an approximation: If we only know the type, but not the cid, we
// might have a this-dispatch where we know it's either this class or any
// subclass.
// We try to strengthen this assumption furher down by checking the offset
// of the type argument vector, but generally speaking this could be a
// false-postive, which is still ok!
const AbstractType& type = *instance->Type()->ToAbstractType();
if (type.IsType()) {
const Class& type_class = Class::Handle(type.type_class());
if (type_class.NumTypeArguments() >= klass.NumTypeArguments()) {
cid = type_class.id();
}
}
}
if (cid != kDynamicCid) {
const Class& instance_klass =
Class::Handle(IsolateGroup::Current()->class_table()->At(cid));
if (load_field->slot().IsTypeArguments() && instance_klass.IsGeneric() &&
compiler::target::Class::TypeArgumentsFieldOffset(instance_klass) ==
load_field->slot().offset_in_bytes()) {
// This is a subset of Case c) above, namely forwarding the type
// argument vector.
//
// We use the declaration type arguments for the instance creation,
// which is a non-instantiated, expanded, type arguments vector.
const Type& declaration_type =
Type::Handle(instance_klass.DeclarationType());
TypeArguments& declaration_type_args =
TypeArguments::Handle(declaration_type.arguments());
type_usage_info->UseTypeArgumentsInInstanceCreation(
klass, declaration_type_args);
}
}
} else if (type_arguments->IsParameter() ||
type_arguments->IsLoadIndexedUnsafe()) {
// This happens in constructors with non-optional/optional parameters
// where we forward the type argument vector to object allocation.
//
// Theoretically this could be a false-positive, which is still ok, but
// practically it's guaranteed that this is a forward of a type argument
// vector passed in by the caller.
if (function.IsFactory()) {
const Class& enclosing_class = Class::Handle(function.Owner());
const Type& declaration_type =
Type::Handle(enclosing_class.DeclarationType());
TypeArguments& declaration_type_args =
TypeArguments::Handle(declaration_type.arguments());
type_usage_info->UseTypeArgumentsInInstanceCreation(
klass, declaration_type_args);
}
} else {
// It can also be a phi node where the inputs are any of the above,
// or it could be the result of _prependTypeArguments call.
ASSERT(type_arguments->IsPhi() || type_arguments->IsStaticCall());
}
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
#else // !defined(TARGET_ARCH_IA32)
#if !defined(DART_PRECOMPILED_RUNTIME)
void RegisterTypeArgumentsUse(const Function& function,
TypeUsageInfo* type_usage_info,
const Class& klass,
Definition* type_arguments) {
// We only have a [TypeUsageInfo] object available durin AOT compilation.
UNREACHABLE();
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
#endif // !defined(TARGET_ARCH_IA32)
#undef __
const TypeArguments& TypeArgumentInstantiator::InstantiateTypeArguments(
const Class& klass,
const TypeArguments& type_arguments) {
const intptr_t len = klass.NumTypeArguments();
ScopedHandle<TypeArguments> instantiated_type_arguments(
&type_arguments_handles_);
*instantiated_type_arguments = TypeArguments::New(len);
for (intptr_t i = 0; i < len; ++i) {
type_ = type_arguments.TypeAt(i);
type_ = InstantiateType(type_);
instantiated_type_arguments->SetTypeAt(i, type_);
ASSERT(type_.IsCanonical() ||
(type_.IsTypeRef() &&
AbstractType::Handle(TypeRef::Cast(type_).type()).IsCanonical()));
}
*instantiated_type_arguments =
instantiated_type_arguments->Canonicalize(Thread::Current(), nullptr);
return *instantiated_type_arguments;
}
AbstractTypePtr TypeArgumentInstantiator::InstantiateType(
const AbstractType& type) {
if (type.IsTypeParameter()) {
const TypeParameter& parameter = TypeParameter::Cast(type);
ASSERT(parameter.IsClassTypeParameter());
ASSERT(parameter.IsFinalized());
if (instantiator_type_arguments_.IsNull()) {
return Type::DynamicType();
}
AbstractType& result = AbstractType::Handle(
instantiator_type_arguments_.TypeAt(parameter.index()));
result = result.SetInstantiatedNullability(TypeParameter::Cast(type),
Heap::kOld);
return result.NormalizeFutureOrType(Heap::kOld);
} else if (type.IsFunctionType()) {
// No support for function types yet.
UNREACHABLE();
return nullptr;
} else if (type.IsTypeRef()) {
// No support for recursive types.
UNREACHABLE();
return nullptr;
} else if (type.IsType()) {
if (type.IsInstantiated() || type.arguments() == TypeArguments::null()) {
return type.ptr();
}
const Type& from = Type::Cast(type);
klass_ = from.type_class();
ScopedHandle<Type> to(&type_handles_);
ScopedHandle<TypeArguments> to_type_arguments(&type_arguments_handles_);
*to_type_arguments = TypeArguments::null();
*to = Type::New(klass_, *to_type_arguments);
*to_type_arguments = from.arguments();
to->set_arguments(InstantiateTypeArguments(klass_, *to_type_arguments));
to->SetIsFinalized();
*to ^= to->Canonicalize(Thread::Current(), nullptr);
return to->ptr();
}
UNREACHABLE();
return NULL;
}
TypeUsageInfo::TypeUsageInfo(Thread* thread)
: ThreadStackResource(thread),
zone_(thread->zone()),
finder_(zone_),
assert_assignable_types_(),
instance_creation_arguments_(
new TypeArgumentsSet
[thread->isolate_group()->class_table()->NumCids()]),
klass_(Class::Handle(zone_)) {
thread->set_type_usage_info(this);
}
TypeUsageInfo::~TypeUsageInfo() {
thread()->set_type_usage_info(NULL);
delete[] instance_creation_arguments_;
}
void TypeUsageInfo::UseTypeInAssertAssignable(const AbstractType& type) {
if (!assert_assignable_types_.HasKey(&type)) {
AddTypeToSet(&assert_assignable_types_, &type);
}
}
void TypeUsageInfo::UseTypeArgumentsInInstanceCreation(
const Class& klass,
const TypeArguments& ta) {
if (ta.IsNull() || ta.IsCanonical()) {
// The Dart VM performs an optimization where it re-uses type argument
// vectors if the use-site needs a prefix of an already-existent type
// arguments vector.
//
// For example:
//
// class Foo<K, V> {
// foo() => new Bar<K>();
// }
//
// So the length of the type arguments vector can be longer than the number
// of type arguments the class expects.
ASSERT(ta.IsNull() || klass.NumTypeArguments() <= ta.Length());
// If this is a non-instantiated [TypeArguments] object, then it referes to
// type parameters. We need to ensure the type parameters in [ta] only
// refer to type parameters in the class.
if (!ta.IsNull() && !ta.IsInstantiated() &&
finder_.FindClass(ta).IsNull()) {
return;
}
klass_ = klass.ptr();
while (klass_.NumTypeArguments() > 0) {
const intptr_t cid = klass_.id();
TypeArgumentsSet& set = instance_creation_arguments_[cid];
if (!set.HasKey(&ta)) {
set.Insert(&TypeArguments::ZoneHandle(zone_, ta.ptr()));
}
klass_ = klass_.SuperClass();
}
}
}
void TypeUsageInfo::BuildTypeUsageInformation() {
ClassTable* class_table = thread()->isolate_group()->class_table();
const intptr_t cid_count = class_table->NumCids();
// Step 1) Propagate instantiated type argument vectors.
PropagateTypeArguments(class_table, cid_count);
// Step 2) Collect the type parameters we're interested in.
TypeParameterSet parameters_tested_against;
CollectTypeParametersUsedInAssertAssignable(&parameters_tested_against);
// Step 2) Add all types which flow into a type parameter we test against to
// the set of types tested against.
UpdateAssertAssignableTypes(class_table, cid_count,
&parameters_tested_against);
}
void TypeUsageInfo::PropagateTypeArguments(ClassTable* class_table,
intptr_t cid_count) {
// See comment in .h file for what this method does.
Class& klass = Class::Handle(zone_);
TypeArguments& temp_type_arguments = TypeArguments::Handle(zone_);
// We cannot modify a set while we are iterating over it, so we delay the
// addition to the set to the point when iteration has finished and use this
// list as temporary storage.
GrowableObjectArray& delayed_type_argument_set =
GrowableObjectArray::Handle(zone_, GrowableObjectArray::New());
TypeArgumentInstantiator instantiator(zone_);
const intptr_t kPropgationRounds = 2;
for (intptr_t round = 0; round < kPropgationRounds; ++round) {
for (intptr_t cid = 0; cid < cid_count; ++cid) {
if (!class_table->IsValidIndex(cid) ||
!class_table->HasValidClassAt(cid)) {
continue;
}
klass = class_table->At(cid);
bool null_in_delayed_type_argument_set = false;
delayed_type_argument_set.SetLength(0);
auto it = instance_creation_arguments_[cid].GetIterator();
for (const TypeArguments** type_arguments = it.Next();
type_arguments != nullptr; type_arguments = it.Next()) {
// We have a "type allocation" with "klass<type_arguments[0:N]>".
if (!(*type_arguments)->IsNull() &&
!(*type_arguments)->IsInstantiated()) {
const Class& enclosing_class = finder_.FindClass(**type_arguments);
if (!klass.IsNull()) {
// We know that "klass<type_arguments[0:N]>" happens inside
// [enclosing_class].
if (enclosing_class.ptr() != klass.ptr()) {
// Now we try to instantiate [type_arguments] with all the known
// instantiator type argument vectors of the [enclosing_class].
const intptr_t enclosing_class_cid = enclosing_class.id();
TypeArgumentsSet& instantiator_set =
instance_creation_arguments_[enclosing_class_cid];
auto it2 = instantiator_set.GetIterator();
for (const TypeArguments** instantiator_type_arguments =
it2.Next();
instantiator_type_arguments != nullptr;
instantiator_type_arguments = it2.Next()) {
// We have also a "type allocation" with
// "enclosing_class<instantiator_type_arguments[0:M]>".
if ((*instantiator_type_arguments)->IsNull() ||
(*instantiator_type_arguments)->IsInstantiated()) {
temp_type_arguments = instantiator.Instantiate(
klass, **type_arguments, **instantiator_type_arguments);
if (temp_type_arguments.IsNull() &&
!null_in_delayed_type_argument_set) {
null_in_delayed_type_argument_set = true;
delayed_type_argument_set.Add(temp_type_arguments);
} else {
delayed_type_argument_set.Add(temp_type_arguments);
}
}
}
}
}
}
}
// Now we add the [delayed_type_argument_set] elements to the set of
// instantiator type arguments of [klass] (and its superclasses).
if (delayed_type_argument_set.Length() > 0) {
while (klass.NumTypeArguments() > 0) {
TypeArgumentsSet& type_argument_set =
instance_creation_arguments_[klass.id()];
const intptr_t len = delayed_type_argument_set.Length();
for (intptr_t i = 0; i < len; ++i) {
temp_type_arguments =
TypeArguments::RawCast(delayed_type_argument_set.At(i));
if (!type_argument_set.HasKey(&temp_type_arguments)) {
type_argument_set.Insert(
&TypeArguments::ZoneHandle(zone_, temp_type_arguments.ptr()));
}
}
klass = klass.SuperClass();
}
}
}
}
}
void TypeUsageInfo::CollectTypeParametersUsedInAssertAssignable(
TypeParameterSet* set) {
TypeParameter& param = TypeParameter::Handle(zone_);
auto it = assert_assignable_types_.GetIterator();
for (const AbstractType** type = it.Next(); type != nullptr;
type = it.Next()) {
AddToSetIfParameter(set, *type, &param);
}
}
void TypeUsageInfo::UpdateAssertAssignableTypes(
ClassTable* class_table,
intptr_t cid_count,
TypeParameterSet* parameters_tested_against) {
Class& klass = Class::Handle(zone_);
TypeParameter& param = TypeParameter::Handle(zone_);
AbstractType& type = AbstractType::Handle(zone_);
// Because Object/dynamic are common values for type parameters, we add them
// eagerly and avoid doing it down inside the loop.
type = Type::DynamicType();
UseTypeInAssertAssignable(type);
type = Type::ObjectType(); // TODO(regis): Add nullable Object?
UseTypeInAssertAssignable(type);
for (intptr_t cid = 0; cid < cid_count; ++cid) {
if (!class_table->IsValidIndex(cid) || !class_table->HasValidClassAt(cid)) {
continue;
}
klass = class_table->At(cid);
if (klass.NumTypeArguments() <= 0) {
continue;
}
const intptr_t num_parameters = klass.NumTypeParameters();
for (intptr_t i = 0; i < num_parameters; ++i) {
param = klass.TypeParameterAt(i);
if (parameters_tested_against->HasKey(&param)) {
TypeArgumentsSet& ta_set = instance_creation_arguments_[cid];
auto it = ta_set.GetIterator();
for (const TypeArguments** ta = it.Next(); ta != nullptr;
ta = it.Next()) {
// We only add instantiated types to the set (and dynamic/Object were
// already handled above).
if (!(*ta)->IsNull()) {
type = (*ta)->TypeAt(i);
if (type.IsInstantiated()) {
UseTypeInAssertAssignable(type);
}
}
}
}
}
}
}
void TypeUsageInfo::AddToSetIfParameter(TypeParameterSet* set,
const AbstractType* type,
TypeParameter* param) {
if (type->IsTypeParameter()) {
*param ^= type->ptr();
if (!param->IsNull() && !set->HasKey(param)) {
set->Insert(&TypeParameter::Handle(zone_, param->ptr()));
}
}
}
void TypeUsageInfo::AddTypeToSet(TypeSet* set, const AbstractType* type) {
if (!set->HasKey(type)) {
set->Insert(&AbstractType::ZoneHandle(zone_, type->ptr()));
}
}
bool TypeUsageInfo::IsUsedInTypeTest(const AbstractType& type) {
const AbstractType* dereferenced_type = &type;
if (type.IsTypeRef()) {
dereferenced_type = &AbstractType::Handle(TypeRef::Cast(type).type());
}
if (dereferenced_type->IsFinalized()) {
return assert_assignable_types_.HasKey(dereferenced_type);
}
return false;
}
#if !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
void DeoptimizeTypeTestingStubs() {
class CollectTypes : public ObjectVisitor {
public:
CollectTypes(Zone* zone, GrowableArray<AbstractType*>* types)
: zone_(zone), types_(types), cache_(SubtypeTestCache::Handle(zone)) {}
void VisitObject(ObjectPtr object) {
// Only types and function types may have optimized TTSes.
if (object->IsType() || object->IsFunctionType()) {
types_->Add(&AbstractType::CheckedHandle(zone_, object));
} else if (object->IsSubtypeTestCache()) {
cache_ ^= object;
cache_.Reset();
}
}
private:
Zone* const zone_;
GrowableArray<AbstractType*>* const types_;
TypeTestingStubGenerator generator_;
SubtypeTestCache& cache_;
};
Thread* thread = Thread::Current();
TIMELINE_DURATION(thread, Isolate, "DeoptimizeTypeTestingStubs");
HANDLESCOPE(thread);
Zone* zone = thread->zone();
GrowableArray<AbstractType*> types(zone, 0);
{
HeapIterationScope iter(thread);
CollectTypes visitor(zone, &types);
iter.IterateObjects(&visitor);
}
auto& stub = Code::Handle(zone);
for (auto* const type : types) {
stub = TypeTestingStubGenerator::DefaultCodeForType(*type);
type->SetTypeTestingStub(stub);
}
}
#endif // !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
} // namespace dart