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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/builtins/constants-table-builder.h"
#include "src/execution/isolate.h"
#include "src/heap/heap-inl.h"
#include "src/objects/oddball-inl.h"
#include "src/roots/roots-inl.h"
namespace v8 {
namespace internal {
BuiltinsConstantsTableBuilder::BuiltinsConstantsTableBuilder(Isolate* isolate)
: isolate_(isolate), map_(isolate->heap()) {
// Ensure this is only called once per Isolate.
DCHECK_EQ(ReadOnlyRoots(isolate_).empty_fixed_array(),
isolate_->heap()->builtins_constants_table());
// And that the initial value of the builtins constants table can be treated
// as a constant, which means that codegen will load it using the root
// register.
DCHECK(RootsTable::IsImmortalImmovable(RootIndex::kEmptyFixedArray));
}
uint32_t BuiltinsConstantsTableBuilder::AddObject(Handle<Object> object) {
#ifdef DEBUG
// Roots must not be inserted into the constants table as they are already
// accessibly from the root list.
RootIndex root_list_index;
DCHECK(!isolate_->roots_table().IsRootHandle(object, &root_list_index));
// Not yet finalized.
DCHECK_EQ(ReadOnlyRoots(isolate_).empty_fixed_array(),
isolate_->heap()->builtins_constants_table());
// Must be on the main thread.
DCHECK_EQ(ThreadId::Current(), isolate_->thread_id());
// Must be generating embedded builtin code.
DCHECK(isolate_->IsGeneratingEmbeddedBuiltins());
// All code objects should be loaded through the root register or use
// pc-relative addressing.
DCHECK(!object->IsCode());
#endif
auto find_result = map_.FindOrInsert(object);
if (!find_result.already_exists) {
DCHECK(object->IsHeapObject());
*find_result.entry = map_.size() - 1;
}
return *find_result.entry;
}
namespace {
void CheckPreconditionsForPatching(Isolate* isolate,
Handle<Object> replacement_object) {
// Roots must not be inserted into the constants table as they are already
// accessible from the root list.
RootIndex root_list_index;
DCHECK(!isolate->roots_table().IsRootHandle(replacement_object,
&root_list_index));
USE(root_list_index);
// Not yet finalized.
DCHECK_EQ(ReadOnlyRoots(isolate).empty_fixed_array(),
isolate->heap()->builtins_constants_table());
DCHECK(isolate->IsGeneratingEmbeddedBuiltins());
}
} // namespace
void BuiltinsConstantsTableBuilder::PatchSelfReference(
Handle<Object> self_reference, Handle<Code> code_object) {
CheckPreconditionsForPatching(isolate_, code_object);
DCHECK(self_reference->IsOddball());
DCHECK(Oddball::cast(*self_reference).kind() ==
Oddball::kSelfReferenceMarker);
uint32_t key;
if (map_.Delete(self_reference, &key)) {
DCHECK(code_object->IsCode());
map_.Insert(code_object, key);
}
}
void BuiltinsConstantsTableBuilder::PatchBasicBlockCountersReference(
Handle<ByteArray> counters) {
CheckPreconditionsForPatching(isolate_, counters);
uint32_t key;
if (map_.Delete(ReadOnlyRoots(isolate_).basic_block_counters_marker(),
&key)) {
map_.Insert(counters, key);
}
}
void BuiltinsConstantsTableBuilder::Finalize() {
HandleScope handle_scope(isolate_);
DCHECK_EQ(ReadOnlyRoots(isolate_).empty_fixed_array(),
isolate_->heap()->builtins_constants_table());
DCHECK(isolate_->IsGeneratingEmbeddedBuiltins());
// An empty map means there's nothing to do.
if (map_.size() == 0) return;
Handle<FixedArray> table =
isolate_->factory()->NewFixedArray(map_.size(), AllocationType::kOld);
Builtins* builtins = isolate_->builtins();
ConstantsMap::IteratableScope it_scope(&map_);
for (auto it = it_scope.begin(); it != it_scope.end(); ++it) {
uint32_t index = *it.entry();
Object value = it.key();
if (value.IsCode() && Code::cast(value).kind() == CodeKind::BUILTIN) {
// Replace placeholder code objects with the real builtin.
// See also: SetupIsolateDelegate::PopulateWithPlaceholders.
// TODO(jgruber): Deduplicate placeholders and their corresponding
// builtin.
value = builtins->code(Code::cast(value).builtin_id());
}
DCHECK(value.IsHeapObject());
table->set(index, value);
}
#ifdef DEBUG
for (int i = 0; i < map_.size(); i++) {
DCHECK(table->get(i).IsHeapObject());
DCHECK_NE(ReadOnlyRoots(isolate_).undefined_value(), table->get(i));
DCHECK_NE(ReadOnlyRoots(isolate_).self_reference_marker(), table->get(i));
DCHECK_NE(ReadOnlyRoots(isolate_).basic_block_counters_marker(),
table->get(i));
}
#endif
isolate_->heap()->SetBuiltinsConstantsTable(*table);
}
} // namespace internal
} // namespace v8
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