deps/v8/src/compilation-cache.cc

   1 // Copyright 2011 the V8 project authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "src/v8.h"
   6
   7 #include "src/assembler.h"
   8 #include "src/compilation-cache.h"
   9
  10 namespace v8 {
  11 namespace internal {
  12
  13
  14 // The number of generations for each sub cache.
  15 static const int kRegExpGenerations = 2;
  16
  17 // Initial size of each compilation cache table allocated.
  18 static const int kInitialCacheSize = 64;
  19
  20
  21 CompilationCache::CompilationCache(Isolate* isolate)
  22     : isolate_(isolate),
  23       script_(isolate, 1),
  24       eval_global_(isolate, 1),
  25       eval_contextual_(isolate, 1),
  26       reg_exp_(isolate, kRegExpGenerations),
  27       enabled_(true) {
  28   CompilationSubCache* subcaches[kSubCacheCount] =
  29     {&script_, &eval_global_, &eval_contextual_, &reg_exp_};
  30   for (int i = 0; i < kSubCacheCount; ++i) {
  31     subcaches_[i] = subcaches[i];
  32   }
  33 }
  34
  35
  36 CompilationCache::~CompilationCache() {}
  37
  38
  39 Handle<CompilationCacheTable> CompilationSubCache::GetTable(int generation) {
  40   DCHECK(generation < generations_);
  41   Handle<CompilationCacheTable> result;
  42   if (tables_[generation]->IsUndefined()) {
  43     result = CompilationCacheTable::New(isolate(), kInitialCacheSize);
  44     tables_[generation] = *result;
  45   } else {
  46     CompilationCacheTable* table =
  47         CompilationCacheTable::cast(tables_[generation]);
  48     result = Handle<CompilationCacheTable>(table, isolate());
  49   }
  50   return result;
  51 }
  52
  53
  54 void CompilationSubCache::Age() {
  55   // Don't directly age single-generation caches.
  56   if (generations_ == 1) {
  57     if (tables_[0] != isolate()->heap()->undefined_value()) {
  58       CompilationCacheTable::cast(tables_[0])->Age();
  59     }
  60     return;
  61   }
  62
  63   // Age the generations implicitly killing off the oldest.
  64   for (int i = generations_ - 1; i > 0; i--) {
  65     tables_[i] = tables_[i - 1];
  66   }
  67
  68   // Set the first generation as unborn.
  69   tables_[0] = isolate()->heap()->undefined_value();
  70 }
  71
  72
  73 void CompilationSubCache::IterateFunctions(ObjectVisitor* v) {
  74   Object* undefined = isolate()->heap()->undefined_value();
  75   for (int i = 0; i < generations_; i++) {
  76     if (tables_[i] != undefined) {
  77       reinterpret_cast<CompilationCacheTable*>(tables_[i])->IterateElements(v);
  78     }
  79   }
  80 }
  81
  82
  83 void CompilationSubCache::Iterate(ObjectVisitor* v) {
  84   v->VisitPointers(&tables_[0], &tables_[generations_]);
  85 }
  86
  87
  88 void CompilationSubCache::Clear() {
  89   MemsetPointer(tables_, isolate()->heap()->undefined_value(), generations_);
  90 }
  91
  92
  93 void CompilationSubCache::Remove(Handle<SharedFunctionInfo> function_info) {
  94   // Probe the script generation tables. Make sure not to leak handles
  95   // into the caller's handle scope.
  96   { HandleScope scope(isolate());
  97     for (int generation = 0; generation < generations(); generation++) {
  98       Handle<CompilationCacheTable> table = GetTable(generation);
  99       table->Remove(*function_info);
 100     }
 101   }
 102 }
 103
 104
 105 CompilationCacheScript::CompilationCacheScript(Isolate* isolate,
 106                                                int generations)
 107     : CompilationSubCache(isolate, generations) {}
 108
 109
 110 // We only re-use a cached function for some script source code if the
 111 // script originates from the same place. This is to avoid issues
 112 // when reporting errors, etc.
 113 bool CompilationCacheScript::HasOrigin(Handle<SharedFunctionInfo> function_info,
 114                                        Handle<Object> name, int line_offset,
 115                                        int column_offset,
 116                                        bool is_embedder_debug_script,
 117                                        bool is_shared_cross_origin) {
 118   Handle<Script> script =
 119       Handle<Script>(Script::cast(function_info->script()), isolate());
 120   // If the script name isn't set, the boilerplate script should have
 121   // an undefined name to have the same origin.
 122   if (name.is_null()) {
 123     return script->name()->IsUndefined();
 124   }
 125   // Do the fast bailout checks first.
 126   if (line_offset != script->line_offset()->value()) return false;
 127   if (column_offset != script->column_offset()->value()) return false;
 128   // Check that both names are strings. If not, no match.
 129   if (!name->IsString() || !script->name()->IsString()) return false;
 130   // Were both scripts tagged by the embedder as being internal script?
 131   if (is_embedder_debug_script != script->is_embedder_debug_script()) {
 132     return false;
 133   }
 134   // Were both scripts tagged by the embedder as being shared cross-origin?
 135   if (is_shared_cross_origin != script->is_shared_cross_origin()) return false;
 136   // Compare the two name strings for equality.
 137   return String::Equals(Handle<String>::cast(name),
 138                         Handle<String>(String::cast(script->name())));
 139 }
 140
 141
 142 // TODO(245): Need to allow identical code from different contexts to
 143 // be cached in the same script generation. Currently the first use
 144 // will be cached, but subsequent code from different source / line
 145 // won't.
 146 Handle<SharedFunctionInfo> CompilationCacheScript::Lookup(
 147     Handle<String> source, Handle<Object> name, int line_offset,
 148     int column_offset, bool is_embedder_debug_script,
 149     bool is_shared_cross_origin, Handle<Context> context,
 150     LanguageMode language_mode) {
 151   Object* result = NULL;
 152   int generation;
 153
 154   // Probe the script generation tables. Make sure not to leak handles
 155   // into the caller's handle scope.
 156   { HandleScope scope(isolate());
 157     for (generation = 0; generation < generations(); generation++) {
 158       Handle<CompilationCacheTable> table = GetTable(generation);
 159       Handle<Object> probe = table->Lookup(source, context, language_mode);
 160       if (probe->IsSharedFunctionInfo()) {
 161         Handle<SharedFunctionInfo> function_info =
 162             Handle<SharedFunctionInfo>::cast(probe);
 163         // Break when we've found a suitable shared function info that
 164         // matches the origin.
 165         if (HasOrigin(function_info, name, line_offset, column_offset,
 166                       is_embedder_debug_script, is_shared_cross_origin)) {
 167           result = *function_info;
 168           break;
 169         }
 170       }
 171     }
 172   }
 173
 174   // Once outside the manacles of the handle scope, we need to recheck
 175   // to see if we actually found a cached script. If so, we return a
 176   // handle created in the caller's handle scope.
 177   if (result != NULL) {
 178     Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(result),
 179                                       isolate());
 180     DCHECK(HasOrigin(shared, name, line_offset, column_offset,
 181                      is_embedder_debug_script, is_shared_cross_origin));
 182     // If the script was found in a later generation, we promote it to
 183     // the first generation to let it survive longer in the cache.
 184     if (generation != 0) Put(source, context, language_mode, shared);
 185     isolate()->counters()->compilation_cache_hits()->Increment();
 186     return shared;
 187   } else {
 188     isolate()->counters()->compilation_cache_misses()->Increment();
 189     return Handle<SharedFunctionInfo>::null();
 190   }
 191 }
 192
 193
 194 void CompilationCacheScript::Put(Handle<String> source,
 195                                  Handle<Context> context,
 196                                  LanguageMode language_mode,
 197                                  Handle<SharedFunctionInfo> function_info) {
 198   HandleScope scope(isolate());
 199   Handle<CompilationCacheTable> table = GetFirstTable();
 200   SetFirstTable(CompilationCacheTable::Put(table, source, context,
 201                                            language_mode, function_info));
 202 }
 203
 204
 205 MaybeHandle<SharedFunctionInfo> CompilationCacheEval::Lookup(
 206     Handle<String> source, Handle<SharedFunctionInfo> outer_info,
 207     LanguageMode language_mode, int scope_position) {
 208   HandleScope scope(isolate());
 209   // Make sure not to leak the table into the surrounding handle
 210   // scope. Otherwise, we risk keeping old tables around even after
 211   // having cleared the cache.
 212   Handle<Object> result = isolate()->factory()->undefined_value();
 213   int generation;
 214   for (generation = 0; generation < generations(); generation++) {
 215     Handle<CompilationCacheTable> table = GetTable(generation);
 216     result =
 217         table->LookupEval(source, outer_info, language_mode, scope_position);
 218     if (result->IsSharedFunctionInfo()) break;
 219   }
 220   if (result->IsSharedFunctionInfo()) {
 221     Handle<SharedFunctionInfo> function_info =
 222         Handle<SharedFunctionInfo>::cast(result);
 223     if (generation != 0) {
 224       Put(source, outer_info, function_info, scope_position);
 225     }
 226     isolate()->counters()->compilation_cache_hits()->Increment();
 227     return scope.CloseAndEscape(function_info);
 228   } else {
 229     isolate()->counters()->compilation_cache_misses()->Increment();
 230     return MaybeHandle<SharedFunctionInfo>();
 231   }
 232 }
 233
 234
 235 void CompilationCacheEval::Put(Handle<String> source,
 236                                Handle<SharedFunctionInfo> outer_info,
 237                                Handle<SharedFunctionInfo> function_info,
 238                                int scope_position) {
 239   HandleScope scope(isolate());
 240   Handle<CompilationCacheTable> table = GetFirstTable();
 241   table = CompilationCacheTable::PutEval(table, source, outer_info,
 242                                          function_info, scope_position);
 243   SetFirstTable(table);
 244 }
 245
 246
 247 MaybeHandle<FixedArray> CompilationCacheRegExp::Lookup(
 248     Handle<String> source,
 249     JSRegExp::Flags flags) {
 250   HandleScope scope(isolate());
 251   // Make sure not to leak the table into the surrounding handle
 252   // scope. Otherwise, we risk keeping old tables around even after
 253   // having cleared the cache.
 254   Handle<Object> result = isolate()->factory()->undefined_value();
 255   int generation;
 256   for (generation = 0; generation < generations(); generation++) {
 257     Handle<CompilationCacheTable> table = GetTable(generation);
 258     result = table->LookupRegExp(source, flags);
 259     if (result->IsFixedArray()) break;
 260   }
 261   if (result->IsFixedArray()) {
 262     Handle<FixedArray> data = Handle<FixedArray>::cast(result);
 263     if (generation != 0) {
 264       Put(source, flags, data);
 265     }
 266     isolate()->counters()->compilation_cache_hits()->Increment();
 267     return scope.CloseAndEscape(data);
 268   } else {
 269     isolate()->counters()->compilation_cache_misses()->Increment();
 270     return MaybeHandle<FixedArray>();
 271   }
 272 }
 273
 274
 275 void CompilationCacheRegExp::Put(Handle<String> source,
 276                                  JSRegExp::Flags flags,
 277                                  Handle<FixedArray> data) {
 278   HandleScope scope(isolate());
 279   Handle<CompilationCacheTable> table = GetFirstTable();
 280   SetFirstTable(CompilationCacheTable::PutRegExp(table, source, flags, data));
 281 }
 282
 283
 284 void CompilationCache::Remove(Handle<SharedFunctionInfo> function_info) {
 285   if (!IsEnabled()) return;
 286
 287   eval_global_.Remove(function_info);
 288   eval_contextual_.Remove(function_info);
 289   script_.Remove(function_info);
 290 }
 291
 292
 293 MaybeHandle<SharedFunctionInfo> CompilationCache::LookupScript(
 294     Handle<String> source, Handle<Object> name, int line_offset,
 295     int column_offset, bool is_embedder_debug_script,
 296     bool is_shared_cross_origin, Handle<Context> context,
 297     LanguageMode language_mode) {
 298   if (!IsEnabled()) return MaybeHandle<SharedFunctionInfo>();
 299
 300   return script_.Lookup(source, name, line_offset, column_offset,
 301                         is_embedder_debug_script, is_shared_cross_origin,
 302                         context, language_mode);
 303 }
 304
 305
 306 MaybeHandle<SharedFunctionInfo> CompilationCache::LookupEval(
 307     Handle<String> source, Handle<SharedFunctionInfo> outer_info,
 308     Handle<Context> context, LanguageMode language_mode, int scope_position) {
 309   if (!IsEnabled()) return MaybeHandle<SharedFunctionInfo>();
 310
 311   MaybeHandle<SharedFunctionInfo> result;
 312   if (context->IsNativeContext()) {
 313     result =
 314         eval_global_.Lookup(source, outer_info, language_mode, scope_position);
 315   } else {
 316     DCHECK(scope_position != RelocInfo::kNoPosition);
 317     result = eval_contextual_.Lookup(source, outer_info, language_mode,
 318                                      scope_position);
 319   }
 320   return result;
 321 }
 322
 323
 324 MaybeHandle<FixedArray> CompilationCache::LookupRegExp(Handle<String> source,
 325                                                        JSRegExp::Flags flags) {
 326   if (!IsEnabled()) return MaybeHandle<FixedArray>();
 327
 328   return reg_exp_.Lookup(source, flags);
 329 }
 330
 331
 332 void CompilationCache::PutScript(Handle<String> source,
 333                                  Handle<Context> context,
 334                                  LanguageMode language_mode,
 335                                  Handle<SharedFunctionInfo> function_info) {
 336   if (!IsEnabled()) return;
 337
 338   script_.Put(source, context, language_mode, function_info);
 339 }
 340
 341
 342 void CompilationCache::PutEval(Handle<String> source,
 343                                Handle<SharedFunctionInfo> outer_info,
 344                                Handle<Context> context,
 345                                Handle<SharedFunctionInfo> function_info,
 346                                int scope_position) {
 347   if (!IsEnabled()) return;
 348
 349   HandleScope scope(isolate());
 350   if (context->IsNativeContext()) {
 351     eval_global_.Put(source, outer_info, function_info, scope_position);
 352   } else {
 353     DCHECK(scope_position != RelocInfo::kNoPosition);
 354     eval_contextual_.Put(source, outer_info, function_info, scope_position);
 355   }
 356 }
 357
 358
 359
 360 void CompilationCache::PutRegExp(Handle<String> source,
 361                                  JSRegExp::Flags flags,
 362                                  Handle<FixedArray> data) {
 363   if (!IsEnabled()) {
 364     return;
 365   }
 366
 367   reg_exp_.Put(source, flags, data);
 368 }
 369
 370
 371 void CompilationCache::Clear() {
 372   for (int i = 0; i < kSubCacheCount; i++) {
 373     subcaches_[i]->Clear();
 374   }
 375 }
 376
 377
 378 void CompilationCache::Iterate(ObjectVisitor* v) {
 379   for (int i = 0; i < kSubCacheCount; i++) {
 380     subcaches_[i]->Iterate(v);
 381   }
 382 }
 383
 384
 385 void CompilationCache::IterateFunctions(ObjectVisitor* v) {
 386   for (int i = 0; i < kSubCacheCount; i++) {
 387     subcaches_[i]->IterateFunctions(v);
 388   }
 389 }
 390
 391
 392 void CompilationCache::MarkCompactPrologue() {
 393   for (int i = 0; i < kSubCacheCount; i++) {
 394     subcaches_[i]->Age();
 395   }
 396 }
 397
 398
 399 void CompilationCache::Enable() {
 400   enabled_ = true;
 401 }
 402
 403
 404 void CompilationCache::Disable() {
 405   enabled_ = false;
 406   Clear();
 407 }
 408
 409
 410 } }  // namespace v8::internal