// 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(); // Remove given shared function info from sub-cache. void Remove(Handle<SharedFunctionInfo> function_info); // 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 MaybeObject* 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, StrictModeFlag strict_mode); void Put(Handle<String> source, Handle<Context> context, Handle<SharedFunctionInfo> function_info); private: MUST_USE_RESULT MaybeObject* 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 MaybeObject* 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, ®_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_); } void CompilationSubCache::Remove(Handle<SharedFunctionInfo> function_info) { // Probe the script generation tables. Make sure not to leak handles // into the caller's handle scope. { HandleScope scope; for (int generation = 0; generation < generations(); generation++) { Handle<CompilationCacheTable> table = GetTable(generation); table->Remove(*function_info); } } } // 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(); } } MaybeObject* 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, StrictModeFlag strict_mode) { // 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, strict_mode); 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(); } } MaybeObject* 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(); } } MaybeObject* 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)); } void CompilationCache::Remove(Handle<SharedFunctionInfo> function_info) { if (!IsEnabled()) return; eval_global.Remove(function_info); eval_contextual.Remove(function_info); script.Remove(function_info); } 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, StrictModeFlag strict_mode) { if (!IsEnabled()) { return Handle<SharedFunctionInfo>::null(); } Handle<SharedFunctionInfo> result; if (is_global) { result = eval_global.Lookup(source, context, strict_mode); } else { result = eval_contextual.Lookup(source, context, strict_mode); } 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); } static bool SourceHashCompare(void* key1, void* key2) { return key1 == key2; } static HashMap* EagerOptimizingSet() { static HashMap map(&SourceHashCompare); return ↦ } bool CompilationCache::ShouldOptimizeEagerly(Handle<JSFunction> function) { if (FLAG_opt_eagerly) return true; uint32_t hash = function->SourceHash(); void* key = reinterpret_cast<void*>(hash); return EagerOptimizingSet()->Lookup(key, hash, false) != NULL; } void CompilationCache::MarkForEagerOptimizing(Handle<JSFunction> function) { uint32_t hash = function->SourceHash(); void* key = reinterpret_cast<void*>(hash); EagerOptimizingSet()->Lookup(key, hash, true); } void CompilationCache::MarkForLazyOptimizing(Handle<JSFunction> function) { uint32_t hash = function->SourceHash(); void* key = reinterpret_cast<void*>(hash); EagerOptimizingSet()->Remove(key, hash); } void CompilationCache::ResetEagerOptimizingData() { HashMap* set = EagerOptimizingSet(); if (set->occupancy() > 0) set->Clear(); } 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