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kernel_binary_flowgraph.cc
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kernel_binary_flowgraph.cc
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// Copyright (c) 2016, 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/compiler/frontend/kernel_binary_flowgraph.h"
#include "vm/closure_functions_cache.h"
#include "vm/compiler/ffi/callback.h"
#include "vm/compiler/frontend/flow_graph_builder.h" // For dart::FlowGraphBuilder::SimpleInstanceOfType.
#include "vm/compiler/frontend/prologue_builder.h"
#include "vm/compiler/jit/compiler.h"
#include "vm/object_store.h"
#include "vm/resolver.h"
#include "vm/stack_frame.h"
namespace dart {
namespace kernel {
#define Z (zone_)
#define H (translation_helper_)
#define T (type_translator_)
#define I Isolate::Current()
#define IG IsolateGroup::Current()
#define B (flow_graph_builder_)
Class& StreamingFlowGraphBuilder::GetSuperOrDie() {
Class& klass = Class::Handle(Z, parsed_function()->function().Owner());
ASSERT(!klass.IsNull());
klass = klass.SuperClass();
ASSERT(!klass.IsNull());
return klass;
}
FlowGraph* StreamingFlowGraphBuilder::BuildGraphOfFieldInitializer() {
FieldHelper field_helper(this);
field_helper.ReadUntilExcluding(FieldHelper::kInitializer);
// Constants are directly accessed at use sites of Dart code. In C++ - if
// we need to access static constants - we do so directly using the kernel
// evaluation instead of invoking the initializer function in Dart code.
//
// If the field is marked as @pragma('vm:entry-point') then the embedder might
// invoke the getter, so we'll generate the initializer function.
ASSERT(!field_helper.IsConst() ||
Field::Handle(Z, parsed_function()->function().accessor_field())
.VerifyEntryPoint(EntryPointPragma::kGetterOnly) ==
Error::null());
Tag initializer_tag = ReadTag(); // read first part of initializer.
if (initializer_tag != kSomething) {
UNREACHABLE();
}
B->graph_entry_ = new (Z) GraphEntryInstr(*parsed_function(), B->osr_id_);
auto normal_entry = B->BuildFunctionEntry(B->graph_entry_);
B->graph_entry_->set_normal_entry(normal_entry);
Fragment body(normal_entry);
body += B->CheckStackOverflowInPrologue(field_helper.position_);
body += SetupCapturedParameters(parsed_function()->function());
body += BuildExpression(); // read initializer.
body += Return(TokenPosition::kNoSource);
PrologueInfo prologue_info(-1, -1);
if (B->IsCompiledForOsr()) {
B->graph_entry_->RelinkToOsrEntry(Z, B->last_used_block_id_ + 1);
}
return new (Z) FlowGraph(*parsed_function(), B->graph_entry_,
B->last_used_block_id_, prologue_info);
}
void StreamingFlowGraphBuilder::SetupDefaultParameterValues() {
intptr_t optional_parameter_count =
parsed_function()->function().NumOptionalParameters();
if (optional_parameter_count > 0) {
ZoneGrowableArray<const Instance*>* default_values =
new ZoneGrowableArray<const Instance*>(Z, optional_parameter_count);
AlternativeReadingScope alt(&reader_);
FunctionNodeHelper function_node_helper(this);
function_node_helper.ReadUntilExcluding(
FunctionNodeHelper::kPositionalParameters);
if (parsed_function()->function().HasOptionalNamedParameters()) {
// List of positional.
intptr_t list_length = ReadListLength(); // read list length.
for (intptr_t i = 0; i < list_length; ++i) {
SkipVariableDeclaration(); // read ith variable declaration.
}
// List of named.
list_length = ReadListLength(); // read list length.
ASSERT(optional_parameter_count == list_length);
ASSERT(!parsed_function()->function().HasOptionalPositionalParameters());
for (intptr_t i = 0; i < list_length; ++i) {
Instance* default_value;
// Read ith variable declaration
VariableDeclarationHelper helper(this);
helper.ReadUntilExcluding(VariableDeclarationHelper::kInitializer);
Tag tag = ReadTag(); // read (first part of) initializer.
if (tag == kSomething) {
// This will read the initializer.
default_value = &Instance::ZoneHandle(
Z, constant_reader_.ReadConstantExpression());
} else {
default_value = &Instance::ZoneHandle(Z, Instance::null());
}
default_values->Add(default_value);
}
} else {
// List of positional.
intptr_t list_length = ReadListLength(); // read list length.
ASSERT(list_length == function_node_helper.required_parameter_count_ +
optional_parameter_count);
ASSERT(parsed_function()->function().HasOptionalPositionalParameters());
for (intptr_t i = 0; i < function_node_helper.required_parameter_count_;
++i) {
SkipVariableDeclaration(); // read ith variable declaration.
}
for (intptr_t i = 0; i < optional_parameter_count; ++i) {
Instance* default_value;
// Read ith variable declaration
VariableDeclarationHelper helper(this);
helper.ReadUntilExcluding(VariableDeclarationHelper::kInitializer);
Tag tag = ReadTag(); // read (first part of) initializer.
if (tag == kSomething) {
// This will read the initializer.
default_value = &Instance::ZoneHandle(
Z, constant_reader_.ReadConstantExpression());
} else {
default_value = &Instance::ZoneHandle(Z, Instance::null());
}
default_values->Add(default_value);
}
// List of named.
list_length = ReadListLength(); // read list length.
ASSERT(list_length == 0);
}
parsed_function()->set_default_parameter_values(default_values);
}
}
Fragment StreamingFlowGraphBuilder::BuildFieldInitializer(
const Field& field,
bool only_for_side_effects) {
ASSERT(Error::Handle(Z, H.thread()->sticky_error()).IsNull());
if (PeekTag() == kNullLiteral) {
SkipExpression(); // read past the null literal.
if (H.thread()->IsMutatorThread()) {
ASSERT(field.IsOriginal());
LeaveCompilerScope cs(H.thread());
field.RecordStore(Object::null_object());
} else {
ASSERT(field.is_nullable(/* silence_assert = */ true));
}
return Fragment();
}
Fragment instructions;
if (!only_for_side_effects) {
instructions += LoadLocal(parsed_function()->receiver_var());
}
// All closures created inside BuildExpression will have
// field.RawOwner() as its owner.
closure_owner_ = field.RawOwner();
instructions += BuildExpression();
closure_owner_ = Object::null();
if (only_for_side_effects) {
instructions += Drop();
} else {
instructions += flow_graph_builder_->StoreInstanceFieldGuarded(
field, StoreInstanceFieldInstr::Kind::kInitializing);
}
return instructions;
}
Fragment StreamingFlowGraphBuilder::BuildLateFieldInitializer(
const Field& field,
bool has_initializer) {
if (has_initializer && PeekTag() == kNullLiteral) {
SkipExpression(); // read past the null literal.
if (H.thread()->IsMutatorThread()) {
LeaveCompilerScope cs(H.thread());
field.RecordStore(Object::null_object());
} else {
ASSERT(field.is_nullable(/* silence_assert = */ true));
}
return Fragment();
}
Fragment instructions;
instructions += LoadLocal(parsed_function()->receiver_var());
instructions += flow_graph_builder_->Constant(Object::sentinel());
instructions += flow_graph_builder_->StoreInstanceField(
field, StoreInstanceFieldInstr::Kind::kInitializing);
return instructions;
}
Fragment StreamingFlowGraphBuilder::BuildInitializers(
const Class& parent_class) {
ASSERT(Error::Handle(Z, H.thread()->sticky_error()).IsNull());
Fragment instructions;
// Start by getting the position of the constructors initializer.
intptr_t initializers_offset = -1;
{
AlternativeReadingScope alt(&reader_);
SkipFunctionNode(); // read constructors function node.
initializers_offset = ReaderOffset();
}
bool is_redirecting_constructor = false;
// Field which will be initialized by the initializer with the given index.
GrowableArray<const Field*> initializer_fields(5);
// Check if this is a redirecting constructor and collect all fields which
// will be initialized by the constructor initializer list.
{
AlternativeReadingScope alt(&reader_, initializers_offset);
const intptr_t list_length =
ReadListLength(); // read initializers list length.
initializer_fields.EnsureLength(list_length, nullptr);
bool has_field_initializers = false;
for (intptr_t i = 0; i < list_length; ++i) {
if (PeekTag() == kRedirectingInitializer) {
is_redirecting_constructor = true;
} else if (PeekTag() == kFieldInitializer) {
has_field_initializers = true;
ReadTag();
ReadBool();
const NameIndex field_name = ReadCanonicalNameReference();
const Field& field =
Field::Handle(Z, H.LookupFieldByKernelField(field_name));
initializer_fields[i] = &field;
SkipExpression();
continue;
}
SkipInitializer();
}
ASSERT(!is_redirecting_constructor || !has_field_initializers);
}
// These come from:
//
// class A {
// var x = (expr);
// }
//
// We don't want to do that when this is a Redirecting Constructors though
// (i.e. has a single initializer being of type kRedirectingInitializer).
if (!is_redirecting_constructor) {
// Sort list of fields (represented as their kernel offsets) which will
// be initialized by the constructor initializer list. We will not emit
// StoreInstanceField instructions for those initializers though we will
// still evaluate initialization expression for its side effects.
GrowableArray<intptr_t> constructor_initialized_field_offsets(
initializer_fields.length());
for (auto field : initializer_fields) {
if (field != nullptr) {
constructor_initialized_field_offsets.Add(field->kernel_offset());
}
}
constructor_initialized_field_offsets.Sort(
[](const intptr_t* a, const intptr_t* b) {
return static_cast<int>(*a) - static_cast<int>(*b);
});
constructor_initialized_field_offsets.Add(-1);
ExternalTypedData& kernel_data = ExternalTypedData::Handle(Z);
Array& class_fields = Array::Handle(Z, parent_class.fields());
Field& class_field = Field::Handle(Z);
intptr_t next_constructor_initialized_field_index = 0;
for (intptr_t i = 0; i < class_fields.Length(); ++i) {
class_field ^= class_fields.At(i);
if (!class_field.is_static()) {
const intptr_t field_offset = class_field.kernel_offset();
// Check if this field will be initialized by the constructor
// initializer list.
// Note that both class_fields and the list of initialized fields
// are sorted by their kernel offset (by construction) -
// so we don't need to perform the search.
bool is_constructor_initialized = false;
const intptr_t constructor_initialized_field_offset =
constructor_initialized_field_offsets
[next_constructor_initialized_field_index];
if (constructor_initialized_field_offset == field_offset) {
next_constructor_initialized_field_index++;
is_constructor_initialized = true;
}
kernel_data = class_field.KernelData();
ASSERT(!kernel_data.IsNull());
AlternativeReadingScopeWithNewData alt(&reader_, &kernel_data,
field_offset);
FieldHelper field_helper(this);
field_helper.ReadUntilExcluding(FieldHelper::kInitializer);
const Tag initializer_tag = ReadTag();
if (class_field.is_late()) {
if (!is_constructor_initialized) {
instructions += BuildLateFieldInitializer(
Field::ZoneHandle(Z, class_field.ptr()),
initializer_tag == kSomething);
}
} else if (initializer_tag == kSomething) {
EnterScope(field_offset);
// If this field is initialized in constructor then we can ignore the
// value produced by the field initializer. However we still need to
// execute it for its side effects.
instructions += BuildFieldInitializer(
Field::ZoneHandle(Z, class_field.ptr()),
/*only_for_side_effects=*/is_constructor_initialized);
ExitScope(field_offset);
}
}
}
}
// These to come from:
// class A {
// var x;
// var y;
// A(this.x) : super(expr), y = (expr);
// }
{
AlternativeReadingScope alt(&reader_, initializers_offset);
intptr_t list_length = ReadListLength(); // read initializers list length.
for (intptr_t i = 0; i < list_length; ++i) {
Tag tag = ReadTag();
bool isSynthetic = ReadBool(); // read isSynthetic flag.
switch (tag) {
case kInvalidInitializer:
UNIMPLEMENTED();
return Fragment();
case kFieldInitializer: {
ReadCanonicalNameReference();
instructions += BuildFieldInitializer(
Field::ZoneHandle(Z, initializer_fields[i]->ptr()),
/*only_for_size_effects=*/false);
break;
}
case kAssertInitializer: {
instructions += BuildStatement();
break;
}
case kSuperInitializer: {
TokenPosition position = ReadPosition(); // read position.
NameIndex canonical_target =
ReadCanonicalNameReference(); // read target_reference.
instructions += LoadLocal(parsed_function()->receiver_var());
// TODO(jensj): ASSERT(init->arguments()->types().length() == 0);
Array& argument_names = Array::ZoneHandle(Z);
intptr_t argument_count;
instructions += BuildArguments(
&argument_names, &argument_count,
/* positional_parameter_count = */ NULL); // read arguments.
argument_count += 1;
Class& parent_klass = GetSuperOrDie();
const Function& target = Function::ZoneHandle(
Z, H.LookupConstructorByKernelConstructor(
parent_klass, H.CanonicalNameString(canonical_target)));
instructions += StaticCall(
isSynthetic ? TokenPosition::kNoSource : position, target,
argument_count, argument_names, ICData::kStatic);
instructions += Drop();
break;
}
case kRedirectingInitializer: {
TokenPosition position = ReadPosition(); // read position.
NameIndex canonical_target =
ReadCanonicalNameReference(); // read target_reference.
instructions += LoadLocal(parsed_function()->receiver_var());
// TODO(jensj): ASSERT(init->arguments()->types().length() == 0);
Array& argument_names = Array::ZoneHandle(Z);
intptr_t argument_count;
instructions += BuildArguments(
&argument_names, &argument_count,
/* positional_parameter_count = */ NULL); // read arguments.
argument_count += 1;
const Function& target = Function::ZoneHandle(
Z, H.LookupConstructorByKernelConstructor(canonical_target));
instructions += StaticCall(
isSynthetic ? TokenPosition::kNoSource : position, target,
argument_count, argument_names, ICData::kStatic);
instructions += Drop();
break;
}
case kLocalInitializer: {
// The other initializers following this one might read the variable.
// This is used e.g. for evaluating the arguments to a super call
// first, run normal field initializers next and then make the actual
// super call:
//
// The frontend converts
//
// class A {
// var x;
// A(a, b) : super(a + b), x = 2*b {}
// }
//
// to
//
// class A {
// var x;
// A(a, b) : tmp = a + b, x = 2*b, super(tmp) {}
// }
//
// (This is strictly speaking not what one should do in terms of the
// specification but that is how it is currently implemented.)
LocalVariable* variable =
LookupVariable(ReaderOffset() + data_program_offset_);
// Variable declaration
VariableDeclarationHelper helper(this);
helper.ReadUntilExcluding(VariableDeclarationHelper::kInitializer);
ASSERT(!helper.IsConst());
Tag tag = ReadTag(); // read (first part of) initializer.
if (tag != kSomething) {
UNREACHABLE();
}
instructions += BuildExpression(); // read initializer.
instructions += StoreLocal(TokenPosition::kNoSource, variable);
instructions += Drop();
break;
}
default:
ReportUnexpectedTag("initializer", tag);
UNREACHABLE();
}
}
}
return instructions;
}
Fragment StreamingFlowGraphBuilder::DebugStepCheckInPrologue(
const Function& dart_function,
TokenPosition position) {
if (!NeedsDebugStepCheck(dart_function, position)) {
return {};
}
// Place this check at the last parameter to ensure parameters
// are in scope in the debugger at method entry.
const int parameter_count = dart_function.NumParameters();
TokenPosition check_pos = TokenPosition::kNoSource;
if (parameter_count > 0) {
const LocalVariable& parameter =
*parsed_function()->ParameterVariable(parameter_count - 1);
check_pos = parameter.token_pos();
}
if (!check_pos.IsDebugPause()) {
// No parameters or synthetic parameters.
check_pos = position;
ASSERT(check_pos.IsDebugPause());
}
return DebugStepCheck(check_pos);
}
Fragment StreamingFlowGraphBuilder::TypeArgumentsHandling(
const Function& dart_function) {
Fragment prologue = B->BuildDefaultTypeHandling(dart_function);
if (dart_function.IsClosureFunction() &&
dart_function.NumParentTypeArguments() > 0) {
LocalVariable* closure = parsed_function()->ParameterVariable(0);
// Function with yield points can not be generic itself but the outer
// function can be.
ASSERT(yield_continuations().is_empty() || !dart_function.IsGeneric());
LocalVariable* fn_type_args = parsed_function()->function_type_arguments();
ASSERT(fn_type_args != NULL && closure != NULL);
if (dart_function.IsGeneric()) {
prologue += LoadLocal(fn_type_args);
prologue += LoadLocal(closure);
prologue += LoadNativeField(Slot::Closure_function_type_arguments());
prologue += IntConstant(dart_function.NumParentTypeArguments());
prologue += IntConstant(dart_function.NumTypeArguments());
const auto& prepend_function =
flow_graph_builder_->PrependTypeArgumentsFunction();
prologue += StaticCall(TokenPosition::kNoSource, prepend_function, 4,
ICData::kStatic);
prologue += StoreLocal(TokenPosition::kNoSource, fn_type_args);
prologue += Drop();
} else {
prologue += LoadLocal(closure);
prologue += LoadNativeField(Slot::Closure_function_type_arguments());
prologue += StoreLocal(TokenPosition::kNoSource, fn_type_args);
prologue += Drop();
}
}
return prologue;
}
Fragment StreamingFlowGraphBuilder::CompleteBodyWithYieldContinuations(
Fragment body) {
// The code we are building will be executed right after we enter
// the function and before any nested contexts are allocated.
// Reset current context_depth_ to match this.
const intptr_t current_context_depth = B->context_depth_;
B->context_depth_ = scopes()->yield_jump_variable->owner()->context_level();
// Prepend an entry corresponding to normal entry to the function.
yield_continuations().InsertAt(
0, YieldContinuation(new (Z) DropTempsInstr(0, NULL), kInvalidTryIndex));
yield_continuations()[0].entry->LinkTo(body.entry);
// Load :await_jump_var into a temporary.
Fragment dispatch;
dispatch += LoadLocal(scopes()->yield_jump_variable);
dispatch += StoreLocal(TokenPosition::kNoSource, scopes()->switch_variable);
dispatch += Drop();
const intptr_t continuation_count = yield_continuations().length();
IndirectGotoInstr* indirect_goto;
if (FLAG_async_igoto_threshold >= 0 &&
continuation_count >= FLAG_async_igoto_threshold) {
const auto& offsets = TypedData::ZoneHandle(
Z, TypedData::New(kTypedDataInt32ArrayCid, continuation_count,
Heap::kOld));
dispatch += Constant(offsets);
dispatch += LoadLocal(scopes()->switch_variable);
// Ideally this would just be LoadIndexed(kTypedDataInt32ArrayCid),
// but that doesn't work in unoptimised code.
// The optimiser will turn this into that in any case.
dispatch += InstanceCall(TokenPosition::kNoSource, Symbols::IndexToken(),
Token::kINDEX, /*argument_count=*/2);
Value* offset_from_start = Pop();
indirect_goto = new (Z) IndirectGotoInstr(&offsets, offset_from_start);
dispatch <<= indirect_goto;
for (intptr_t i = 0; i < continuation_count; i++) {
if (i >= 1) {
Fragment resumption;
// Every continuation after the first is not a normal entry but a
// resumption.
// Restore :current_context_var from :await_ctx_var.
// Note: after this point context_depth_ does not match current context
// depth so we should not access any local variables anymore.
resumption += LoadLocal(scopes()->yield_context_variable);
resumption += StoreLocal(TokenPosition::kNoSource,
parsed_function()->current_context_var());
resumption += Drop();
Instruction* next = yield_continuations()[i].entry->next();
yield_continuations()[i].entry->LinkTo(resumption.entry);
resumption <<= next;
}
IndirectEntryInstr* indirect_entry = B->BuildIndirectEntry(
/*indirect_id=*/i, yield_continuations()[i].try_index);
indirect_entry->LinkTo(yield_continuations()[i].entry->next());
TargetEntryInstr* target = B->BuildTargetEntry();
Fragment(target) + Goto(indirect_entry);
indirect_goto->AddSuccessor(target);
}
} else {
BlockEntryInstr* block = nullptr;
for (intptr_t i = 0; i < continuation_count; i++) {
if (i == 1) {
// This is not a normal entry but a resumption. Restore
// :current_context_var from :await_ctx_var.
// Note: after this point context_depth_ does not match current context
// depth so we should not access any local variables anymore.
dispatch += LoadLocal(scopes()->yield_context_variable);
dispatch += StoreLocal(TokenPosition::kNoSource,
parsed_function()->current_context_var());
dispatch += Drop();
}
if (i == (continuation_count - 1)) {
// We reached the last possibility, no need to build more ifs.
// Continue to the last continuation.
// Note: continuations start with nop DropTemps instruction
// which acts like an anchor, so we need to skip it.
block->set_try_index(yield_continuations()[i].try_index);
dispatch <<= yield_continuations()[i].entry->next();
break;
}
// Build comparison:
//
// if (:await_jump_var == i) {
// -> yield_continuations()[i]
// } else ...
//
TargetEntryInstr* then;
TargetEntryInstr* otherwise;
dispatch += LoadLocal(scopes()->switch_variable);
dispatch += IntConstant(i);
dispatch += B->BranchIfStrictEqual(&then, &otherwise);
// True branch is linked to appropriate continuation point.
// Note: continuations start with nop DropTemps instruction
// which acts like an anchor, so we need to skip it.
then->LinkTo(yield_continuations()[i].entry->next());
then->set_try_index(yield_continuations()[i].try_index);
// False branch will contain the next comparison.
dispatch = Fragment(dispatch.entry, otherwise);
block = otherwise;
}
}
B->context_depth_ = current_context_depth;
return dispatch;
}
Fragment StreamingFlowGraphBuilder::CheckStackOverflowInPrologue(
const Function& dart_function) {
if (dart_function.is_native()) return {};
return B->CheckStackOverflowInPrologue(dart_function.token_pos());
}
Fragment StreamingFlowGraphBuilder::SetupCapturedParameters(
const Function& dart_function) {
Fragment body;
const LocalScope* scope = parsed_function()->scope();
if (scope->num_context_variables() > 0) {
body += flow_graph_builder_->PushContext(scope);
LocalVariable* context = MakeTemporary();
// Copy captured parameters from the stack into the context.
LocalScope* scope = parsed_function()->scope();
intptr_t parameter_count = dart_function.NumParameters();
const ParsedFunction& pf = *flow_graph_builder_->parsed_function_;
const Function& function = pf.function();
for (intptr_t i = 0; i < parameter_count; ++i) {
LocalVariable* variable = pf.ParameterVariable(i);
if (variable->is_captured()) {
LocalVariable& raw_parameter = *pf.RawParameterVariable(i);
ASSERT((function.HasOptionalParameters() &&
raw_parameter.owner() == scope) ||
(!function.HasOptionalParameters() &&
raw_parameter.owner() == NULL));
ASSERT(!raw_parameter.is_captured());
// Copy the parameter from the stack to the context.
body += LoadLocal(context);
body += LoadLocal(&raw_parameter);
body += flow_graph_builder_->StoreInstanceField(
TokenPosition::kNoSource,
Slot::GetContextVariableSlotFor(thread(), *variable),
StoreInstanceFieldInstr::Kind::kInitializing);
}
}
body += Drop(); // The context.
}
return body;
}
Fragment StreamingFlowGraphBuilder::ShortcutForUserDefinedEquals(
const Function& dart_function,
LocalVariable* first_parameter) {
// The specification defines the result of `a == b` to be:
//
// a) if either side is `null` then the result is `identical(a, b)`.
// b) else the result is `a.operator==(b)`
//
// For user-defined implementations of `operator==` we need therefore
// implement the handling of a).
//
// The default `operator==` implementation in `Object` is implemented in terms
// of identical (which we assume here!) which means that case a) is actually
// included in b). So we just use the normal implementation in the body.
Fragment body;
if ((dart_function.NumParameters() == 2) &&
(dart_function.name() == Symbols::EqualOperator().ptr()) &&
(dart_function.Owner() != IG->object_store()->object_class())) {
TargetEntryInstr* null_entry;
TargetEntryInstr* non_null_entry;
body += LoadLocal(first_parameter);
body += BranchIfNull(&null_entry, &non_null_entry);
// The argument was `null` and the receiver is not the null class (we only
// go into this branch for user-defined == operators) so we can return
// false.
Fragment null_fragment(null_entry);
null_fragment += Constant(Bool::False());
null_fragment += Return(dart_function.end_token_pos());
body = Fragment(body.entry, non_null_entry);
}
return body;
}
Fragment StreamingFlowGraphBuilder::BuildFunctionBody(
const Function& dart_function,
LocalVariable* first_parameter,
bool constructor) {
Fragment body;
// TODO(27590): Currently the [VariableDeclaration]s from the
// initializers will be visible inside the entire body of the constructor.
// We should make a separate scope for them.
if (constructor) {
body += BuildInitializers(Class::Handle(Z, dart_function.Owner()));
}
if (body.is_closed()) return body;
FunctionNodeHelper function_node_helper(this);
function_node_helper.ReadUntilExcluding(FunctionNodeHelper::kBody);
const bool has_body = ReadTag() == kSomething; // read first part of body.
if (dart_function.is_native()) {
body += B->NativeFunctionBody(dart_function, first_parameter);
} else if (has_body) {
body += BuildStatement();
} else if (dart_function.is_external()) {
body += ThrowNoSuchMethodError(dart_function);
}
if (body.is_open()) {
body += NullConstant();
body += Return(dart_function.end_token_pos());
}
return body;
}
Fragment StreamingFlowGraphBuilder::BuildEveryTimePrologue(
const Function& dart_function,
TokenPosition token_position,
intptr_t type_parameters_offset) {
Fragment F;
F += CheckStackOverflowInPrologue(dart_function);
F += DebugStepCheckInPrologue(dart_function, token_position);
F += B->InitConstantParameters();
return F;
}
Fragment StreamingFlowGraphBuilder::BuildFirstTimePrologue(
const Function& dart_function,
LocalVariable* first_parameter,
intptr_t type_parameters_offset) {
Fragment F;
F += SetupCapturedParameters(dart_function);
F += ShortcutForUserDefinedEquals(dart_function, first_parameter);
return F;
}
Fragment StreamingFlowGraphBuilder::ClearRawParameters(
const Function& dart_function) {
const ParsedFunction& pf = *flow_graph_builder_->parsed_function_;
Fragment code;
for (intptr_t i = 0; i < dart_function.NumParameters(); ++i) {
LocalVariable* variable = pf.ParameterVariable(i);
if (!variable->is_captured()) continue;
// Captured 'this' is immutable, so within the outer method we don't need to
// load it from the context. Therefore we don't reset it to null.
if (pf.function().HasThisParameter() && pf.has_receiver_var() &&
variable == pf.receiver_var()) {
ASSERT(i == 0);
continue;
}
variable = pf.RawParameterVariable(i);
code += NullConstant();
code += StoreLocal(TokenPosition::kNoSource, variable);
code += Drop();
}
return code;
}
UncheckedEntryPointStyle StreamingFlowGraphBuilder::ChooseEntryPointStyle(
const Function& dart_function,
const Fragment& implicit_type_checks,
const Fragment& first_time_prologue,
const Fragment& every_time_prologue,
const Fragment& type_args_handling) {
ASSERT(!dart_function.IsImplicitClosureFunction());
if (!dart_function.MayHaveUncheckedEntryPoint() ||
implicit_type_checks.is_empty()) {
return UncheckedEntryPointStyle::kNone;
}
// Record which entry-point was taken into a variable and test it later if
// either:
//
// 1. There is a non-empty PrologueBuilder-prologue.
//
// 2. There is a non-empty "first-time" prologue.
//
// 3. The "every-time" prologue has more than two instructions (DebugStepCheck
// and CheckStackOverflow).
//
// TODO(#34162): For regular closures we can often avoid the
// PrologueBuilder-prologue on non-dynamic invocations.
if (!PrologueBuilder::HasEmptyPrologue(dart_function) ||
!type_args_handling.is_empty() || !first_time_prologue.is_empty() ||
!(every_time_prologue.entry == every_time_prologue.current ||
every_time_prologue.current->previous() == every_time_prologue.entry)) {
return UncheckedEntryPointStyle::kSharedWithVariable;
}
return UncheckedEntryPointStyle::kSeparate;
}
FlowGraph* StreamingFlowGraphBuilder::BuildGraphOfFunction(
bool is_constructor) {
const Function& dart_function = parsed_function()->function();
intptr_t type_parameters_offset = 0;
LocalVariable* first_parameter = nullptr;
TokenPosition token_position = TokenPosition::kNoSource;
{
AlternativeReadingScope alt(&reader_);
FunctionNodeHelper function_node_helper(this);
function_node_helper.ReadUntilExcluding(
FunctionNodeHelper::kTypeParameters);
type_parameters_offset = ReaderOffset();
function_node_helper.ReadUntilExcluding(
FunctionNodeHelper::kPositionalParameters);
intptr_t list_length = ReadListLength(); // read number of positionals.
if (list_length > 0) {
intptr_t first_parameter_offset = ReaderOffset() + data_program_offset_;
first_parameter = LookupVariable(first_parameter_offset);
}
token_position = function_node_helper.position_;
}
auto graph_entry = flow_graph_builder_->graph_entry_ =
new (Z) GraphEntryInstr(*parsed_function(), flow_graph_builder_->osr_id_);
auto normal_entry = flow_graph_builder_->BuildFunctionEntry(graph_entry);
graph_entry->set_normal_entry(normal_entry);
PrologueInfo prologue_info(-1, -1);
BlockEntryInstr* instruction_cursor =
flow_graph_builder_->BuildPrologue(normal_entry, &prologue_info);
// The 'every_time_prologue' runs first and is run when resuming from yield
// points.
const Fragment every_time_prologue = BuildEveryTimePrologue(
dart_function, token_position, type_parameters_offset);
// The 'first_time_prologue' run after 'every_time_prologue' and is *not* run
// when resuming from yield points.
const Fragment first_time_prologue = BuildFirstTimePrologue(
dart_function, first_parameter, type_parameters_offset);
// TODO(#34162): We can remove the default type handling (and
// shorten the prologue type handling sequence) for non-dynamic invocations of
// regular methods.
const Fragment type_args_handling = TypeArgumentsHandling(dart_function);
Fragment implicit_type_checks;
if (dart_function.NeedsTypeArgumentTypeChecks()) {
B->BuildTypeArgumentTypeChecks(
TypeChecksToBuild::kCheckCovariantTypeParameterBounds,
&implicit_type_checks);
}
Fragment explicit_type_checks;
Fragment implicit_redefinitions;
if (dart_function.NeedsArgumentTypeChecks()) {
B->BuildArgumentTypeChecks(&explicit_type_checks, &implicit_type_checks,
&implicit_redefinitions);
}
// The RawParameter variables should be set to null to avoid retaining more
// objects than necessary during GC.
const Fragment body =
ClearRawParameters(dart_function) + B->BuildNullAssertions() +
BuildFunctionBody(dart_function, first_parameter, is_constructor);
auto extra_entry_point_style = ChooseEntryPointStyle(
dart_function, implicit_type_checks, first_time_prologue,
every_time_prologue, type_args_handling);
Fragment function(instruction_cursor);
if (yield_continuations().is_empty()) {
FunctionEntryInstr* extra_entry = nullptr;
switch (extra_entry_point_style) {
case UncheckedEntryPointStyle::kNone: {
function += every_time_prologue + first_time_prologue +
type_args_handling + implicit_type_checks +
explicit_type_checks + body;
break;
}
case UncheckedEntryPointStyle::kSeparate: {
ASSERT(instruction_cursor == normal_entry);
ASSERT(first_time_prologue.is_empty());
ASSERT(type_args_handling.is_empty());
const Fragment prologue_copy = BuildEveryTimePrologue(
dart_function, token_position, type_parameters_offset);
extra_entry = B->BuildSeparateUncheckedEntryPoint(
normal_entry,
/*normal_prologue=*/every_time_prologue + implicit_type_checks,
/*extra_prologue=*/prologue_copy,
/*shared_prologue=*/explicit_type_checks,
/*body=*/body);
break;
}
case UncheckedEntryPointStyle::kSharedWithVariable: {
Fragment prologue(normal_entry, instruction_cursor);
prologue += every_time_prologue;
prologue += first_time_prologue;
prologue += type_args_handling;
prologue += explicit_type_checks;
extra_entry = B->BuildSharedUncheckedEntryPoint(
/*shared_prologue_linked_in=*/prologue,
/*skippable_checks=*/implicit_type_checks,
/*redefinitions_if_skipped=*/implicit_redefinitions,
/*body=*/body);
break;
}
}
if (extra_entry != nullptr) {
B->RecordUncheckedEntryPoint(graph_entry, extra_entry);
}
} else {
// If the function's body contains any yield points, build switch statement
// that selects a continuation point based on the value of :await_jump_var.
ASSERT(explicit_type_checks.is_empty());
// If the function is generic, type_args_handling might require access to
// (possibly captured) 'this' for preparing default type arguments, in which
// case we can't run it before the 'first_time_prologue'.
ASSERT(!dart_function.IsGeneric());
// TODO(#34162): We can probably ignore the implicit checks
// here as well since the arguments are passed from generated code.
function += every_time_prologue + type_args_handling +
CompleteBodyWithYieldContinuations(first_time_prologue +
implicit_type_checks + body);
}
// When compiling for OSR, use a depth first search to find the OSR
// entry and make graph entry jump to it instead of normal entry.
// Catch entries are always considered reachable, even if they
// become unreachable after OSR.
if (flow_graph_builder_->IsCompiledForOsr()) {
graph_entry->RelinkToOsrEntry(Z,
flow_graph_builder_->last_used_block_id_ + 1);
}
return new (Z)
FlowGraph(*parsed_function(), graph_entry,
flow_graph_builder_->last_used_block_id_, prologue_info);
}
FlowGraph* StreamingFlowGraphBuilder::BuildGraph() {
ASSERT(Error::Handle(Z, H.thread()->sticky_error()).IsNull());
ASSERT(flow_graph_builder_ != nullptr);
const Function& function = parsed_function()->function();
// Setup a [ActiveClassScope] and a [ActiveMemberScope] which will be used
// e.g. for type translation.
const Class& klass =
Class::Handle(zone_, parsed_function()->function().Owner());
Function& outermost_function =
Function::Handle(Z, function.GetOutermostFunction());
ActiveClassScope active_class_scope(active_class(), &klass);
ActiveMemberScope active_member(active_class(), &outermost_function);
FunctionType& signature = FunctionType::Handle(Z, function.signature());
ActiveTypeParametersScope active_type_params(active_class(), function,
&signature, Z);
ParseKernelASTFunction();
switch (function.kind()) {
case UntaggedFunction::kRegularFunction: