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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/roots/roots.h"
#include <type_traits>
#include "src/common/globals.h"
#include "src/objects/elements-kind.h"
#include "src/objects/objects-inl.h"
#include "src/objects/visitors.h"
#include "src/roots/static-roots.h"
namespace v8 {
namespace internal {
static_assert(static_cast<int>(RootIndex::kUndefinedValue) ==
Internals::kUndefinedValueRootIndex);
static_assert(static_cast<int>(RootIndex::kTheHoleValue) ==
Internals::kTheHoleValueRootIndex);
static_assert(static_cast<int>(RootIndex::kNullValue) ==
Internals::kNullValueRootIndex);
static_assert(static_cast<int>(RootIndex::kTrueValue) ==
Internals::kTrueValueRootIndex);
static_assert(static_cast<int>(RootIndex::kFalseValue) ==
Internals::kFalseValueRootIndex);
static_assert(static_cast<int>(RootIndex::kempty_string) ==
Internals::kEmptyStringRootIndex);
const char* RootsTable::root_names_[RootsTable::kEntriesCount] = {
#define ROOT_NAME(type, name, CamelName) #name,
ROOT_LIST(ROOT_NAME)
#undef ROOT_NAME
};
MapWord ReadOnlyRoots::one_pointer_filler_map_word() {
return MapWord::FromMap(one_pointer_filler_map());
}
void ReadOnlyRoots::Iterate(RootVisitor* visitor) {
visitor->VisitRootPointers(Root::kReadOnlyRootList, nullptr,
FullObjectSlot(read_only_roots_),
FullObjectSlot(&read_only_roots_[kEntriesCount]));
visitor->Synchronize(VisitorSynchronization::kReadOnlyRootList);
}
#ifdef DEBUG
void ReadOnlyRoots::VerifyNameForProtectors() {
DisallowGarbageCollection no_gc;
Tagged<Name> prev;
for (RootIndex root_index = RootIndex::kFirstNameForProtector;
root_index <= RootIndex::kLastNameForProtector; ++root_index) {
Tagged<Name> current = Name::cast(object_at(root_index));
DCHECK(IsNameForProtector(current));
if (root_index != RootIndex::kFirstNameForProtector) {
// Make sure the objects are adjacent in memory.
CHECK_LT(prev.address(), current.address());
Address computed_address =
prev.address() + ALIGN_TO_ALLOCATION_ALIGNMENT(prev->Size());
CHECK_EQ(computed_address, current.address());
}
prev = current;
}
}
#define ROOT_TYPE_CHECK(Type, name, CamelName) \
bool ReadOnlyRoots::CheckType_##name() const { \
Tagged<Type> value = unchecked_##name(); \
/* For the oddball subtypes, the "IsFoo" checks only check for address in \
* the RORoots, which is trivially true here. So, do a slow check of the \
* oddball kind instead. Do the casts via Tagged<Object> to satisfy cast \
* compatibility static_asserts in the Tagged class. */ \
if (std::is_same_v<Type, Undefined>) { \
return Tagged<Oddball>::cast(Tagged<Object>(value))->kind() == \
Oddball::kUndefined; \
} else if (std::is_same_v<Type, Null>) { \
return Tagged<Oddball>::cast(Tagged<Object>(value))->kind() == \
Oddball::kNull; \
} else if (std::is_same_v<Type, True>) { \
return Tagged<Oddball>::cast(Tagged<Object>(value))->kind() == \
Oddball::kTrue; \
} else if (std::is_same_v<Type, False>) { \
return Tagged<Oddball>::cast(Tagged<Object>(value))->kind() == \
Oddball::kFalse; \
} else { \
return Is##Type(value); \
} \
}
READ_ONLY_ROOT_LIST(ROOT_TYPE_CHECK)
#undef ROOT_TYPE_CHECK
#endif
Handle<HeapNumber> ReadOnlyRoots::FindHeapNumber(double value) {
auto bits = base::bit_cast<uint64_t>(value);
for (auto pos = RootIndex::kFirstHeapNumberRoot;
pos <= RootIndex::kLastHeapNumberRoot; ++pos) {
auto root = HeapNumber::cast(object_at(pos));
if (base::bit_cast<uint64_t>(root->value()) == bits) {
return Handle<HeapNumber>(GetLocation(pos));
}
}
return Handle<HeapNumber>();
}
void ReadOnlyRoots::InitFromStaticRootsTable(Address cage_base) {
CHECK(V8_STATIC_ROOTS_BOOL);
#if V8_STATIC_ROOTS_BOOL
RootIndex pos = RootIndex::kFirstReadOnlyRoot;
for (auto element : StaticReadOnlyRootsPointerTable) {
auto ptr = V8HeapCompressionScheme::DecompressTagged(cage_base, element);
DCHECK(!is_initialized(pos));
read_only_roots_[static_cast<size_t>(pos)] = ptr;
++pos;
}
DCHECK_EQ(static_cast<int>(pos) - 1, RootIndex::kLastReadOnlyRoot);
#endif // V8_STATIC_ROOTS_BOOL
}
} // namespace internal
} // namespace v8