| // 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" |
| |
| namespace v8 { |
| namespace internal { |
| |
| enum { |
| // The number of script generations tell how many GCs a script can |
| // survive in the compilation cache, before it will be flushed if it |
| // hasn't been used. |
| NUMBER_OF_SCRIPT_GENERATIONS = 8, |
| |
| // The compilation cache consists of tables - one for each entry |
| // kind plus extras for the script generations. |
| NUMBER_OF_TABLE_ENTRIES = |
| CompilationCache::LAST_ENTRY + NUMBER_OF_SCRIPT_GENERATIONS |
| }; |
| |
| |
| // Current enable state of the compilation cache. |
| static bool enabled = true; |
| static inline bool IsEnabled() { |
| return FLAG_compilation_cache && enabled; |
| } |
| |
| // Keep separate tables for the different entry kinds. |
| static Object* tables[NUMBER_OF_TABLE_ENTRIES] = { 0, }; |
| |
| |
| static Handle<CompilationCacheTable> AllocateTable(int size) { |
| CALL_HEAP_FUNCTION(CompilationCacheTable::Allocate(size), |
| CompilationCacheTable); |
| } |
| |
| |
| static Handle<CompilationCacheTable> GetTable(int index) { |
| ASSERT(index >= 0 && index < NUMBER_OF_TABLE_ENTRIES); |
| Handle<CompilationCacheTable> result; |
| if (tables[index]->IsUndefined()) { |
| static const int kInitialCacheSize = 64; |
| result = AllocateTable(kInitialCacheSize); |
| tables[index] = *result; |
| } else { |
| CompilationCacheTable* table = CompilationCacheTable::cast(tables[index]); |
| result = Handle<CompilationCacheTable>(table); |
| } |
| return result; |
| } |
| |
| |
| static Handle<JSFunction> Lookup(Handle<String> source, |
| Handle<Context> context, |
| CompilationCache::Entry entry) { |
| // 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; |
| { HandleScope scope; |
| Handle<CompilationCacheTable> table = GetTable(entry); |
| result = table->LookupEval(*source, *context); |
| } |
| if (result->IsJSFunction()) { |
| return Handle<JSFunction>(JSFunction::cast(result)); |
| } else { |
| return Handle<JSFunction>::null(); |
| } |
| } |
| |
| |
| static Handle<FixedArray> 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; |
| { HandleScope scope; |
| Handle<CompilationCacheTable> table = GetTable(CompilationCache::REGEXP); |
| result = table->LookupRegExp(*source, flags); |
| } |
| if (result->IsFixedArray()) { |
| return Handle<FixedArray>(FixedArray::cast(result)); |
| } else { |
| return Handle<FixedArray>::null(); |
| } |
| } |
| |
| |
| // 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. |
| static bool HasOrigin(Handle<JSFunction> boilerplate, |
| Handle<Object> name, |
| int line_offset, |
| int column_offset) { |
| Handle<Script> script = |
| Handle<Script>(Script::cast(boilerplate->shared()->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<JSFunction> CompilationCache::LookupScript(Handle<String> source, |
| Handle<Object> name, |
| int line_offset, |
| int column_offset) { |
| if (!IsEnabled()) { |
| return Handle<JSFunction>::null(); |
| } |
| |
| // Use an int for the generation index, so value range propagation |
| // in gcc 4.3+ won't assume it can only go up to LAST_ENTRY when in |
| // fact it can go up to SCRIPT + NUMBER_OF_SCRIPT_GENERATIONS. |
| int generation = SCRIPT; |
| Object* result = NULL; |
| |
| // Probe the script generation tables. Make sure not to leak handles |
| // into the caller's handle scope. |
| { HandleScope scope; |
| while (generation < SCRIPT + NUMBER_OF_SCRIPT_GENERATIONS) { |
| Handle<CompilationCacheTable> table = GetTable(generation); |
| Handle<Object> probe(table->Lookup(*source)); |
| if (probe->IsJSFunction()) { |
| Handle<JSFunction> boilerplate = Handle<JSFunction>::cast(probe); |
| // Break when we've found a suitable boilerplate function that |
| // matches the origin. |
| if (HasOrigin(boilerplate, name, line_offset, column_offset)) { |
| result = *boilerplate; |
| break; |
| } |
| } |
| // Go to the next generation. |
| generation++; |
| } |
| } |
| |
| static void* script_histogram = StatsTable::CreateHistogram( |
| "V8.ScriptCache", |
| 0, |
| NUMBER_OF_SCRIPT_GENERATIONS, |
| NUMBER_OF_SCRIPT_GENERATIONS + 1); |
| |
| if (script_histogram != NULL) { |
| // The level NUMBER_OF_SCRIPT_GENERATIONS is equivalent to a cache miss. |
| StatsTable::AddHistogramSample(script_histogram, generation - SCRIPT); |
| } |
| |
| // 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<JSFunction> boilerplate(JSFunction::cast(result)); |
| ASSERT(HasOrigin(boilerplate, 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 != SCRIPT) PutScript(source, boilerplate); |
| Counters::compilation_cache_hits.Increment(); |
| return boilerplate; |
| } else { |
| Counters::compilation_cache_misses.Increment(); |
| return Handle<JSFunction>::null(); |
| } |
| } |
| |
| |
| Handle<JSFunction> CompilationCache::LookupEval(Handle<String> source, |
| Handle<Context> context, |
| Entry entry) { |
| if (!IsEnabled()) { |
| return Handle<JSFunction>::null(); |
| } |
| |
| ASSERT(entry == EVAL_GLOBAL || entry == EVAL_CONTEXTUAL); |
| Handle<JSFunction> result = Lookup(source, context, entry); |
| if (result.is_null()) { |
| Counters::compilation_cache_misses.Increment(); |
| } else { |
| Counters::compilation_cache_hits.Increment(); |
| } |
| return result; |
| } |
| |
| |
| Handle<FixedArray> CompilationCache::LookupRegExp(Handle<String> source, |
| JSRegExp::Flags flags) { |
| if (!IsEnabled()) { |
| return Handle<FixedArray>::null(); |
| } |
| |
| Handle<FixedArray> result = Lookup(source, flags); |
| if (result.is_null()) { |
| Counters::compilation_cache_misses.Increment(); |
| } else { |
| Counters::compilation_cache_hits.Increment(); |
| } |
| return result; |
| } |
| |
| |
| void CompilationCache::PutScript(Handle<String> source, |
| Handle<JSFunction> boilerplate) { |
| if (!IsEnabled()) { |
| return; |
| } |
| |
| HandleScope scope; |
| ASSERT(boilerplate->IsBoilerplate()); |
| Handle<CompilationCacheTable> table = GetTable(SCRIPT); |
| CALL_HEAP_FUNCTION_VOID(table->Put(*source, *boilerplate)); |
| } |
| |
| |
| void CompilationCache::PutEval(Handle<String> source, |
| Handle<Context> context, |
| Entry entry, |
| Handle<JSFunction> boilerplate) { |
| if (!IsEnabled()) { |
| return; |
| } |
| |
| HandleScope scope; |
| ASSERT(boilerplate->IsBoilerplate()); |
| Handle<CompilationCacheTable> table = GetTable(entry); |
| CALL_HEAP_FUNCTION_VOID(table->PutEval(*source, *context, *boilerplate)); |
| } |
| |
| |
| |
| void CompilationCache::PutRegExp(Handle<String> source, |
| JSRegExp::Flags flags, |
| Handle<FixedArray> data) { |
| if (!IsEnabled()) { |
| return; |
| } |
| |
| HandleScope scope; |
| Handle<CompilationCacheTable> table = GetTable(REGEXP); |
| CALL_HEAP_FUNCTION_VOID(table->PutRegExp(*source, flags, *data)); |
| } |
| |
| |
| void CompilationCache::Clear() { |
| for (int i = 0; i < NUMBER_OF_TABLE_ENTRIES; i++) { |
| tables[i] = Heap::undefined_value(); |
| } |
| } |
| |
| |
| void CompilationCache::Iterate(ObjectVisitor* v) { |
| v->VisitPointers(&tables[0], &tables[NUMBER_OF_TABLE_ENTRIES]); |
| } |
| |
| |
| void CompilationCache::MarkCompactPrologue() { |
| ASSERT(LAST_ENTRY == SCRIPT); |
| for (int i = NUMBER_OF_TABLE_ENTRIES - 1; i > SCRIPT; i--) { |
| tables[i] = tables[i - 1]; |
| } |
| for (int j = 0; j <= LAST_ENTRY; j++) { |
| tables[j] = Heap::undefined_value(); |
| } |
| } |
| |
| |
| void CompilationCache::Enable() { |
| enabled = true; |
| } |
| |
| |
| void CompilationCache::Disable() { |
| enabled = false; |
| Clear(); |
| } |
| |
| |
| } } // namespace v8::internal |