v8/src/compilation-cache.cc
vegorov@chromium.org 7c8bb52737 Fix possible evaluation order problems.
We should not allow handle dereference and GC inside the same expression because order of subexpression evalution are not defined.

Review URL: http://codereview.chromium.org/3398014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5509 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2010-09-23 08:27:51 +00:00

587 lines
19 KiB
C++

// Copyright 2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "compilation-cache.h"
#include "serialize.h"
namespace v8 {
namespace internal {
// The number of sub caches covering the different types to cache.
static const int kSubCacheCount = 4;
// The number of generations for each sub cache.
// The number of ScriptGenerations is carefully chosen based on histograms.
// See issue 458: http://code.google.com/p/v8/issues/detail?id=458
static const int kScriptGenerations = 5;
static const int kEvalGlobalGenerations = 2;
static const int kEvalContextualGenerations = 2;
static const int kRegExpGenerations = 2;
// Initial size of each compilation cache table allocated.
static const int kInitialCacheSize = 64;
// Index for the first generation in the cache.
static const int kFirstGeneration = 0;
// The compilation cache consists of several generational sub-caches which uses
// this class as a base class. A sub-cache contains a compilation cache tables
// for each generation of the sub-cache. 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 CompilationSubCache {
public:
explicit CompilationSubCache(int generations): generations_(generations) {
tables_ = NewArray<Object*>(generations);
}
~CompilationSubCache() { DeleteArray(tables_); }
// Get the compilation cache tables for a specific generation.
Handle<CompilationCacheTable> GetTable(int generation);
// Accessors for first generation.
Handle<CompilationCacheTable> GetFirstTable() {
return GetTable(kFirstGeneration);
}
void SetFirstTable(Handle<CompilationCacheTable> value) {
ASSERT(kFirstGeneration < generations_);
tables_[kFirstGeneration] = *value;
}
// Age the sub-cache by evicting the oldest generation and creating a new
// young generation.
void Age();
// GC support.
void Iterate(ObjectVisitor* v);
void IterateFunctions(ObjectVisitor* v);
// Clear this sub-cache evicting all its content.
void Clear();
// Number of generations in this sub-cache.
inline int generations() { return generations_; }
private:
int generations_; // Number of generations.
Object** tables_; // Compilation cache tables - one for each generation.
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationSubCache);
};
// Sub-cache for scripts.
class CompilationCacheScript : public CompilationSubCache {
public:
explicit CompilationCacheScript(int generations)
: CompilationSubCache(generations) { }
Handle<SharedFunctionInfo> Lookup(Handle<String> source,
Handle<Object> name,
int line_offset,
int column_offset);
void Put(Handle<String> source, Handle<SharedFunctionInfo> function_info);
private:
MUST_USE_RESULT Object* TryTablePut(
Handle<String> source, Handle<SharedFunctionInfo> function_info);
// Note: Returns a new hash table if operation results in expansion.
Handle<CompilationCacheTable> TablePut(
Handle<String> source, Handle<SharedFunctionInfo> function_info);
bool HasOrigin(Handle<SharedFunctionInfo> function_info,
Handle<Object> name,
int line_offset,
int column_offset);
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheScript);
};
// Sub-cache for eval scripts.
class CompilationCacheEval: public CompilationSubCache {
public:
explicit CompilationCacheEval(int generations)
: CompilationSubCache(generations) { }
Handle<SharedFunctionInfo> Lookup(Handle<String> source,
Handle<Context> context);
void Put(Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info);
private:
MUST_USE_RESULT Object* TryTablePut(
Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info);
// Note: Returns a new hash table if operation results in expansion.
Handle<CompilationCacheTable> TablePut(
Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info);
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEval);
};
// Sub-cache for regular expressions.
class CompilationCacheRegExp: public CompilationSubCache {
public:
explicit CompilationCacheRegExp(int generations)
: CompilationSubCache(generations) { }
Handle<FixedArray> Lookup(Handle<String> source, JSRegExp::Flags flags);
void Put(Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data);
private:
MUST_USE_RESULT Object* TryTablePut(Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data);
// Note: Returns a new hash table if operation results in expansion.
Handle<CompilationCacheTable> TablePut(Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data);
DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheRegExp);
};
// Statically allocate all the sub-caches.
static CompilationCacheScript script(kScriptGenerations);
static CompilationCacheEval eval_global(kEvalGlobalGenerations);
static CompilationCacheEval eval_contextual(kEvalContextualGenerations);
static CompilationCacheRegExp reg_exp(kRegExpGenerations);
static CompilationSubCache* subcaches[kSubCacheCount] =
{&script, &eval_global, &eval_contextual, &reg_exp};
// Current enable state of the compilation cache.
static bool enabled = true;
static inline bool IsEnabled() {
return FLAG_compilation_cache && enabled;
}
static Handle<CompilationCacheTable> AllocateTable(int size) {
CALL_HEAP_FUNCTION(CompilationCacheTable::Allocate(size),
CompilationCacheTable);
}
Handle<CompilationCacheTable> CompilationSubCache::GetTable(int generation) {
ASSERT(generation < generations_);
Handle<CompilationCacheTable> result;
if (tables_[generation]->IsUndefined()) {
result = AllocateTable(kInitialCacheSize);
tables_[generation] = *result;
} else {
CompilationCacheTable* table =
CompilationCacheTable::cast(tables_[generation]);
result = Handle<CompilationCacheTable>(table);
}
return result;
}
void CompilationSubCache::Age() {
// Age the generations implicitly killing off the oldest.
for (int i = generations_ - 1; i > 0; i--) {
tables_[i] = tables_[i - 1];
}
// Set the first generation as unborn.
tables_[0] = Heap::undefined_value();
}
void CompilationSubCache::IterateFunctions(ObjectVisitor* v) {
Object* undefined = Heap::raw_unchecked_undefined_value();
for (int i = 0; i < generations_; i++) {
if (tables_[i] != undefined) {
reinterpret_cast<CompilationCacheTable*>(tables_[i])->IterateElements(v);
}
}
}
void CompilationSubCache::Iterate(ObjectVisitor* v) {
v->VisitPointers(&tables_[0], &tables_[generations_]);
}
void CompilationSubCache::Clear() {
MemsetPointer(tables_, Heap::undefined_value(), generations_);
}
// We only re-use a cached function for some script source code if the
// script originates from the same place. This is to avoid issues
// when reporting errors, etc.
bool CompilationCacheScript::HasOrigin(
Handle<SharedFunctionInfo> function_info,
Handle<Object> name,
int line_offset,
int column_offset) {
Handle<Script> script =
Handle<Script>(Script::cast(function_info->script()));
// If the script name isn't set, the boilerplate script should have
// an undefined name to have the same origin.
if (name.is_null()) {
return script->name()->IsUndefined();
}
// Do the fast bailout checks first.
if (line_offset != script->line_offset()->value()) return false;
if (column_offset != script->column_offset()->value()) return false;
// Check that both names are strings. If not, no match.
if (!name->IsString() || !script->name()->IsString()) return false;
// Compare the two name strings for equality.
return String::cast(*name)->Equals(String::cast(script->name()));
}
// TODO(245): Need to allow identical code from different contexts to
// be cached in the same script generation. Currently the first use
// will be cached, but subsequent code from different source / line
// won't.
Handle<SharedFunctionInfo> CompilationCacheScript::Lookup(Handle<String> source,
Handle<Object> name,
int line_offset,
int column_offset) {
Object* result = NULL;
int generation;
// Probe the script generation tables. Make sure not to leak handles
// into the caller's handle scope.
{ HandleScope scope;
for (generation = 0; generation < generations(); generation++) {
Handle<CompilationCacheTable> table = GetTable(generation);
Handle<Object> probe(table->Lookup(*source));
if (probe->IsSharedFunctionInfo()) {
Handle<SharedFunctionInfo> function_info =
Handle<SharedFunctionInfo>::cast(probe);
// Break when we've found a suitable shared function info that
// matches the origin.
if (HasOrigin(function_info, name, line_offset, column_offset)) {
result = *function_info;
break;
}
}
}
}
static void* script_histogram = StatsTable::CreateHistogram(
"V8.ScriptCache",
0,
kScriptGenerations,
kScriptGenerations + 1);
if (script_histogram != NULL) {
// The level NUMBER_OF_SCRIPT_GENERATIONS is equivalent to a cache miss.
StatsTable::AddHistogramSample(script_histogram, generation);
}
// Once outside the manacles of the handle scope, we need to recheck
// to see if we actually found a cached script. If so, we return a
// handle created in the caller's handle scope.
if (result != NULL) {
Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(result));
ASSERT(HasOrigin(shared, name, line_offset, column_offset));
// If the script was found in a later generation, we promote it to
// the first generation to let it survive longer in the cache.
if (generation != 0) Put(source, shared);
Counters::compilation_cache_hits.Increment();
return shared;
} else {
Counters::compilation_cache_misses.Increment();
return Handle<SharedFunctionInfo>::null();
}
}
Object* CompilationCacheScript::TryTablePut(
Handle<String> source,
Handle<SharedFunctionInfo> function_info) {
Handle<CompilationCacheTable> table = GetFirstTable();
return table->Put(*source, *function_info);
}
Handle<CompilationCacheTable> CompilationCacheScript::TablePut(
Handle<String> source,
Handle<SharedFunctionInfo> function_info) {
CALL_HEAP_FUNCTION(TryTablePut(source, function_info), CompilationCacheTable);
}
void CompilationCacheScript::Put(Handle<String> source,
Handle<SharedFunctionInfo> function_info) {
HandleScope scope;
SetFirstTable(TablePut(source, function_info));
}
Handle<SharedFunctionInfo> CompilationCacheEval::Lookup(
Handle<String> source, Handle<Context> context) {
// Make sure not to leak the table into the surrounding handle
// scope. Otherwise, we risk keeping old tables around even after
// having cleared the cache.
Object* result = NULL;
int generation;
{ HandleScope scope;
for (generation = 0; generation < generations(); generation++) {
Handle<CompilationCacheTable> table = GetTable(generation);
result = table->LookupEval(*source, *context);
if (result->IsSharedFunctionInfo()) {
break;
}
}
}
if (result->IsSharedFunctionInfo()) {
Handle<SharedFunctionInfo>
function_info(SharedFunctionInfo::cast(result));
if (generation != 0) {
Put(source, context, function_info);
}
Counters::compilation_cache_hits.Increment();
return function_info;
} else {
Counters::compilation_cache_misses.Increment();
return Handle<SharedFunctionInfo>::null();
}
}
Object* CompilationCacheEval::TryTablePut(
Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info) {
Handle<CompilationCacheTable> table = GetFirstTable();
return table->PutEval(*source, *context, *function_info);
}
Handle<CompilationCacheTable> CompilationCacheEval::TablePut(
Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info) {
CALL_HEAP_FUNCTION(TryTablePut(source, context, function_info),
CompilationCacheTable);
}
void CompilationCacheEval::Put(Handle<String> source,
Handle<Context> context,
Handle<SharedFunctionInfo> function_info) {
HandleScope scope;
SetFirstTable(TablePut(source, context, function_info));
}
Handle<FixedArray> CompilationCacheRegExp::Lookup(Handle<String> source,
JSRegExp::Flags flags) {
// Make sure not to leak the table into the surrounding handle
// scope. Otherwise, we risk keeping old tables around even after
// having cleared the cache.
Object* result = NULL;
int generation;
{ HandleScope scope;
for (generation = 0; generation < generations(); generation++) {
Handle<CompilationCacheTable> table = GetTable(generation);
result = table->LookupRegExp(*source, flags);
if (result->IsFixedArray()) {
break;
}
}
}
if (result->IsFixedArray()) {
Handle<FixedArray> data(FixedArray::cast(result));
if (generation != 0) {
Put(source, flags, data);
}
Counters::compilation_cache_hits.Increment();
return data;
} else {
Counters::compilation_cache_misses.Increment();
return Handle<FixedArray>::null();
}
}
Object* CompilationCacheRegExp::TryTablePut(
Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data) {
Handle<CompilationCacheTable> table = GetFirstTable();
return table->PutRegExp(*source, flags, *data);
}
Handle<CompilationCacheTable> CompilationCacheRegExp::TablePut(
Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data) {
CALL_HEAP_FUNCTION(TryTablePut(source, flags, data), CompilationCacheTable);
}
void CompilationCacheRegExp::Put(Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data) {
HandleScope scope;
SetFirstTable(TablePut(source, flags, data));
}
Handle<SharedFunctionInfo> CompilationCache::LookupScript(Handle<String> source,
Handle<Object> name,
int line_offset,
int column_offset) {
if (!IsEnabled()) {
return Handle<SharedFunctionInfo>::null();
}
return script.Lookup(source, name, line_offset, column_offset);
}
Handle<SharedFunctionInfo> CompilationCache::LookupEval(Handle<String> source,
Handle<Context> context,
bool is_global) {
if (!IsEnabled()) {
return Handle<SharedFunctionInfo>::null();
}
Handle<SharedFunctionInfo> result;
if (is_global) {
result = eval_global.Lookup(source, context);
} else {
result = eval_contextual.Lookup(source, context);
}
return result;
}
Handle<FixedArray> CompilationCache::LookupRegExp(Handle<String> source,
JSRegExp::Flags flags) {
if (!IsEnabled()) {
return Handle<FixedArray>::null();
}
return reg_exp.Lookup(source, flags);
}
void CompilationCache::PutScript(Handle<String> source,
Handle<SharedFunctionInfo> function_info) {
if (!IsEnabled()) {
return;
}
script.Put(source, function_info);
}
void CompilationCache::PutEval(Handle<String> source,
Handle<Context> context,
bool is_global,
Handle<SharedFunctionInfo> function_info) {
if (!IsEnabled()) {
return;
}
HandleScope scope;
if (is_global) {
eval_global.Put(source, context, function_info);
} else {
eval_contextual.Put(source, context, function_info);
}
}
void CompilationCache::PutRegExp(Handle<String> source,
JSRegExp::Flags flags,
Handle<FixedArray> data) {
if (!IsEnabled()) {
return;
}
reg_exp.Put(source, flags, data);
}
void CompilationCache::Clear() {
for (int i = 0; i < kSubCacheCount; i++) {
subcaches[i]->Clear();
}
}
void CompilationCache::Iterate(ObjectVisitor* v) {
for (int i = 0; i < kSubCacheCount; i++) {
subcaches[i]->Iterate(v);
}
}
void CompilationCache::IterateFunctions(ObjectVisitor* v) {
for (int i = 0; i < kSubCacheCount; i++) {
subcaches[i]->IterateFunctions(v);
}
}
void CompilationCache::MarkCompactPrologue() {
for (int i = 0; i < kSubCacheCount; i++) {
subcaches[i]->Age();
}
}
void CompilationCache::Enable() {
enabled = true;
}
void CompilationCache::Disable() {
enabled = false;
Clear();
}
} } // namespace v8::internal