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// Copyright 2012 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_CODEGEN_COMPILATION_CACHE_H_
#define V8_CODEGEN_COMPILATION_CACHE_H_
#include "src/base/hashmap.h"
#include "src/objects/compilation-cache-table.h"
#include "src/utils/allocation.h"
namespace v8 {
namespace internal {
class RootVisitor;
struct ScriptDetails;
// The compilation cache consists of several sub-caches: one each for evals and
// scripts, which use this class as a base class, and a separate generational
// sub-cache for RegExps. Since the same source code string has different
// compiled code for scripts and evals, we use separate sub-caches for different
// compilation modes, to avoid retrieving the wrong result.
class CompilationCacheEvalOrScript {
public:
explicit CompilationCacheEvalOrScript(Isolate* isolate) : isolate_(isolate) {}
// Allocates the table if it didn't yet exist.
Handle<CompilationCacheTable> GetTable();
// GC support.
void Iterate(RootVisitor* v);
// Clears this sub-cache evicting all its content.
void Clear();
// Removes given shared function info from sub-cache.
void Remove(Handle<SharedFunctionInfo> function_info);
protected:
Isolate* isolate() const { return isolate_; }
Isolate* const isolate_;
Tagged<Object> table_;
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEvalOrScript);
};
// Sub-cache for scripts.
class CompilationCacheScript : public CompilationCacheEvalOrScript {
public:
explicit CompilationCacheScript(Isolate* isolate)
: CompilationCacheEvalOrScript(isolate) {}
using LookupResult = CompilationCacheScriptLookupResult;
LookupResult Lookup(Handle<String> source,
const ScriptDetails& script_details);
void Put(Handle<String> source, Handle<SharedFunctionInfo> function_info);
void Age();
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheScript);
};
// Sub-cache for eval scripts. Two caches for eval are used. One for eval calls
// in native contexts and one for eval calls in other contexts. The cache
// considers the following pieces of information when checking for matching
// entries:
// 1. The source string.
// 2. The shared function info of the calling function.
// 3. Whether the source should be compiled as strict code or as sloppy code.
// Note: Currently there are clients of CompileEval that always compile
// sloppy code even if the calling function is a strict mode function.
// More specifically these are the CompileString, DebugEvaluate and
// DebugEvaluateGlobal runtime functions.
// 4. The start position of the calling scope.
class CompilationCacheEval : public CompilationCacheEvalOrScript {
public:
explicit CompilationCacheEval(Isolate* isolate)
: CompilationCacheEvalOrScript(isolate) {}
InfoCellPair Lookup(Handle<String> source,
Handle<SharedFunctionInfo> outer_info,
Handle<Context> native_context,
LanguageMode language_mode, int position);
void Put(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
Handle<SharedFunctionInfo> function_info,
Handle<Context> native_context, Handle<FeedbackCell> feedback_cell,
int position);
void Age();
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEval);
};
// Sub-cache for regular expressions.
class CompilationCacheRegExp {
public:
CompilationCacheRegExp(Isolate* isolate) : isolate_(isolate) {}
MaybeHandle<FixedArray> Lookup(Handle<String> source, JSRegExp::Flags flags);
void Put(Handle<String> source, JSRegExp::Flags flags,
Handle<FixedArray> data);
// The number of generations for the RegExp sub cache.
static const int kGenerations = 2;
// Gets the compilation cache tables for a specific generation. Allocates the
// table if it does not yet exist.
Handle<CompilationCacheTable> GetTable(int generation);
// Ages the sub-cache by evicting the oldest generation and creating a new
// young generation.
void Age();
// GC support.
void Iterate(RootVisitor* v);
// Clears this sub-cache evicting all its content.
void Clear();
private:
Isolate* isolate() const { return isolate_; }
Isolate* const isolate_;
Tagged<Object> tables_[kGenerations]; // One for each generation.
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheRegExp);
};
// The compilation cache keeps shared function infos for compiled
// scripts and evals. The shared function infos are looked up using
// the source string as the key. For regular expressions the
// compilation data is cached.
class V8_EXPORT_PRIVATE CompilationCache {
public:
CompilationCache(const CompilationCache&) = delete;
CompilationCache& operator=(const CompilationCache&) = delete;
// Finds the Script and root SharedFunctionInfo for a script source string.
// Returns empty handles if the cache doesn't contain a script for the given
// source string with the right origin.
CompilationCacheScript::LookupResult LookupScript(
Handle<String> source, const ScriptDetails& script_details,
LanguageMode language_mode);
// Finds the shared function info for a source string for eval in a
// given context. Returns an empty handle if the cache doesn't
// contain a script for the given source string.
InfoCellPair LookupEval(Handle<String> source,
Handle<SharedFunctionInfo> outer_info,
Handle<Context> context, LanguageMode language_mode,
int position);
// Returns the regexp data associated with the given regexp if it
// is in cache, otherwise an empty handle.
MaybeHandle<FixedArray> LookupRegExp(Handle<String> source,
JSRegExp::Flags flags);
// Associate the (source, kind) pair to the shared function
// info. This may overwrite an existing mapping.
void PutScript(Handle<String> source, LanguageMode language_mode,
Handle<SharedFunctionInfo> function_info);
// Associate the (source, context->closure()->shared(), kind) triple
// with the shared function info. This may overwrite an existing mapping.
void PutEval(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info,
Handle<FeedbackCell> feedback_cell, int position);
// Associate the (source, flags) pair to the given regexp data.
// This may overwrite an existing mapping.
void PutRegExp(Handle<String> source, JSRegExp::Flags flags,
Handle<FixedArray> data);
// Clear the cache - also used to initialize the cache at startup.
void Clear();
// Remove given shared function info from all caches.
void Remove(Handle<SharedFunctionInfo> function_info);
// GC support.
void Iterate(RootVisitor* v);
// Notify the cache that a mark-sweep garbage collection is about to
// take place. This is used to retire entries from the cache to
// avoid keeping them alive too long without using them.
void MarkCompactPrologue();
// Enable/disable compilation cache. Used by debugger to disable compilation
// cache during debugging so that eval and new scripts are always compiled.
// TODO(bmeurer, chromium:992277): The RegExp cache cannot be enabled and/or
// disabled, since it doesn't affect debugging. However ideally the other
// caches should also be always on, even in the presence of the debugger,
// but at this point there are too many unclear invariants, and so I decided
// to just fix the pressing performance problem for RegExp individually first.
void EnableScriptAndEval();
void DisableScriptAndEval();
private:
explicit CompilationCache(Isolate* isolate);
~CompilationCache() = default;
base::HashMap* EagerOptimizingSet();
bool IsEnabledScriptAndEval() const {
return v8_flags.compilation_cache && enabled_script_and_eval_;
}
bool IsEnabledScript(LanguageMode language_mode) {
// Tests can change v8_flags.use_strict at runtime. The compilation cache
// only contains scripts which were compiled with the default language mode.
return IsEnabledScriptAndEval() && language_mode == LanguageMode::kSloppy;
}
Isolate* isolate() const { return isolate_; }
Isolate* isolate_;
CompilationCacheScript script_;
CompilationCacheEval eval_global_;
CompilationCacheEval eval_contextual_;
CompilationCacheRegExp reg_exp_;
// Current enable state of the compilation cache for scripts and eval.
bool enabled_script_and_eval_;
friend class Isolate;
};
} // namespace internal
} // namespace v8
#endif // V8_CODEGEN_COMPILATION_CACHE_H_
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