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// Copyright 2017 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.
#ifndef V8_OBJECTS_COMPILATION_CACHE_TABLE_INL_H_
#define V8_OBJECTS_COMPILATION_CACHE_TABLE_INL_H_
#include "src/objects/compilation-cache-table.h"
#include "src/objects/name-inl.h"
#include "src/objects/script-inl.h"
#include "src/objects/shared-function-info.h"
#include "src/objects/smi.h"
#include "src/objects/string.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
CompilationCacheTable::CompilationCacheTable(Address ptr)
: HashTable<CompilationCacheTable, CompilationCacheShape>(ptr) {
SLOW_DCHECK(IsCompilationCacheTable());
}
NEVER_READ_ONLY_SPACE_IMPL(CompilationCacheTable)
CAST_ACCESSOR(CompilationCacheTable)
Object CompilationCacheTable::PrimaryValueAt(InternalIndex entry) {
return get(EntryToIndex(entry) + 1);
}
void CompilationCacheTable::SetPrimaryValueAt(InternalIndex entry, Object value,
WriteBarrierMode mode) {
set(EntryToIndex(entry) + 1, value, mode);
}
Object CompilationCacheTable::EvalFeedbackValueAt(InternalIndex entry) {
static_assert(CompilationCacheShape::kEntrySize == 3);
return get(EntryToIndex(entry) + 2);
}
void CompilationCacheTable::SetEvalFeedbackValueAt(InternalIndex entry,
Object value,
WriteBarrierMode mode) {
set(EntryToIndex(entry) + 2, value, mode);
}
// The key in a script cache is a WeakFixedArray containing a weak pointer to
// the Script. The corresponding value can be either the root SharedFunctionInfo
// or undefined. The purpose of storing the root SharedFunctionInfo as the value
// is to keep it alive, not to save a lookup on the Script. A newly added entry
// always contains the root SharedFunctionInfo. After the root
// SharedFunctionInfo has aged sufficiently, it is replaced with undefined. In
// this way, all strong references to large objects are dropped, but there is
// still a way to get the Script if it happens to still be alive.
class ScriptCacheKey : public HashTableKey {
public:
enum Index {
kHash,
kWeakScript,
kEnd,
};
ScriptCacheKey(Handle<String> source, const ScriptDetails* script_details,
Isolate* isolate);
ScriptCacheKey(Handle<String> source, MaybeHandle<Object> name,
int line_offset, int column_offset,
v8::ScriptOriginOptions origin_options,
MaybeHandle<Object> host_defined_options, Isolate* isolate);
bool IsMatch(Object other) override;
bool MatchesOrigin(Script script);
Handle<Object> AsHandle(Isolate* isolate, Handle<SharedFunctionInfo> shared);
static base::Optional<String> SourceFromObject(Object obj) {
DisallowGarbageCollection no_gc;
DCHECK(obj.IsWeakFixedArray());
WeakFixedArray array = WeakFixedArray::cast(obj);
DCHECK_EQ(array.length(), kEnd);
MaybeObject maybe_script = array.Get(kWeakScript);
if (HeapObject script; maybe_script.GetHeapObjectIfWeak(&script)) {
PrimitiveHeapObject source_or_undefined = Script::cast(script).source();
// Scripts stored in the script cache should always have a source string.
return String::cast(source_or_undefined);
}
DCHECK(maybe_script.IsCleared());
return {};
}
private:
Handle<String> source_;
MaybeHandle<Object> name_;
int line_offset_;
int column_offset_;
v8::ScriptOriginOptions origin_options_;
MaybeHandle<Object> host_defined_options_;
Isolate* isolate_;
};
uint32_t CompilationCacheShape::RegExpHash(String string, Smi flags) {
return string.EnsureHash() + flags.value();
}
uint32_t CompilationCacheShape::EvalHash(String source,
SharedFunctionInfo shared,
LanguageMode language_mode,
int position) {
uint32_t hash = source.EnsureHash();
if (shared.HasSourceCode()) {
// Instead of using the SharedFunctionInfo pointer in the hash
// code computation, we use a combination of the hash of the
// script source code and the start position of the calling scope.
// We do this to ensure that the cache entries can survive garbage
// collection.
Script script(Script::cast(shared.script()));
hash ^= String::cast(script.source()).EnsureHash();
}
static_assert(LanguageModeSize == 2);
if (is_strict(language_mode)) hash ^= 0x8000;
hash += position;
return hash;
}
uint32_t CompilationCacheShape::HashForObject(ReadOnlyRoots roots,
Object object) {
// Eval: The key field contains the hash as a Number.
if (object.IsNumber()) return static_cast<uint32_t>(object.Number());
// Code: The key field contains the SFI key.
if (object.IsSharedFunctionInfo()) {
return SharedFunctionInfo::cast(object).Hash();
}
// Script.
if (object.IsWeakFixedArray()) {
uint32_t result = static_cast<uint32_t>(Smi::ToInt(
WeakFixedArray::cast(object).Get(ScriptCacheKey::kHash).ToSmi()));
return result;
}
// Eval: See EvalCacheKey::ToHandle for the encoding.
FixedArray val = FixedArray::cast(object);
if (val.map() == roots.fixed_cow_array_map()) {
DCHECK_EQ(4, val.length());
String source = String::cast(val.get(1));
int language_unchecked = Smi::ToInt(val.get(2));
DCHECK(is_valid_language_mode(language_unchecked));
LanguageMode language_mode = static_cast<LanguageMode>(language_unchecked);
int position = Smi::ToInt(val.get(3));
Object shared = val.get(0);
return EvalHash(source, SharedFunctionInfo::cast(shared), language_mode,
position);
}
// RegExp: The key field (and the value field) contains the
// JSRegExp::data fixed array.
DCHECK_GE(val.length(), JSRegExp::kMinDataArrayLength);
return RegExpHash(String::cast(val.get(JSRegExp::kSourceIndex)),
Smi::cast(val.get(JSRegExp::kFlagsIndex)));
}
InfoCellPair::InfoCellPair(Isolate* isolate, SharedFunctionInfo shared,
FeedbackCell feedback_cell)
: is_compiled_scope_(!shared.is_null() ? shared.is_compiled_scope(isolate)
: IsCompiledScope()),
shared_(shared),
feedback_cell_(feedback_cell) {}
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_COMPILATION_CACHE_TABLE_INL_H_
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