1 // Copyright 2012 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_COMPILATION_CACHE_H_ 29 #define V8_COMPILATION_CACHE_H_ 30 31 namespace v8 { 32 namespace internal { 33 34 // The compilation cache consists of several generational sub-caches which uses 35 // this class as a base class. A sub-cache contains a compilation cache tables 36 // for each generation of the sub-cache. Since the same source code string has 37 // different compiled code for scripts and evals, we use separate sub-caches 38 // for different compilation modes, to avoid retrieving the wrong result. 39 class CompilationSubCache { 40 public: CompilationSubCache(Isolate * isolate,int generations)41 CompilationSubCache(Isolate* isolate, int generations) 42 : isolate_(isolate), 43 generations_(generations) { 44 tables_ = NewArray<Object*>(generations); 45 } 46 ~CompilationSubCache()47 ~CompilationSubCache() { DeleteArray(tables_); } 48 49 // Index for the first generation in the cache. 50 static const int kFirstGeneration = 0; 51 52 // Get the compilation cache tables for a specific generation. 53 Handle<CompilationCacheTable> GetTable(int generation); 54 55 // Accessors for first generation. GetFirstTable()56 Handle<CompilationCacheTable> GetFirstTable() { 57 return GetTable(kFirstGeneration); 58 } SetFirstTable(Handle<CompilationCacheTable> value)59 void SetFirstTable(Handle<CompilationCacheTable> value) { 60 ASSERT(kFirstGeneration < generations_); 61 tables_[kFirstGeneration] = *value; 62 } 63 64 // Age the sub-cache by evicting the oldest generation and creating a new 65 // young generation. 66 void Age(); 67 68 // GC support. 69 void Iterate(ObjectVisitor* v); 70 void IterateFunctions(ObjectVisitor* v); 71 72 // Clear this sub-cache evicting all its content. 73 void Clear(); 74 75 // Remove given shared function info from sub-cache. 76 void Remove(Handle<SharedFunctionInfo> function_info); 77 78 // Number of generations in this sub-cache. generations()79 inline int generations() { return generations_; } 80 81 protected: isolate()82 Isolate* isolate() { return isolate_; } 83 84 private: 85 Isolate* isolate_; 86 int generations_; // Number of generations. 87 Object** tables_; // Compilation cache tables - one for each generation. 88 89 DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationSubCache); 90 }; 91 92 93 // Sub-cache for scripts. 94 class CompilationCacheScript : public CompilationSubCache { 95 public: 96 CompilationCacheScript(Isolate* isolate, int generations); 97 98 Handle<SharedFunctionInfo> Lookup(Handle<String> source, 99 Handle<Object> name, 100 int line_offset, 101 int column_offset); 102 void Put(Handle<String> source, Handle<SharedFunctionInfo> function_info); 103 104 private: 105 MUST_USE_RESULT MaybeObject* TryTablePut( 106 Handle<String> source, Handle<SharedFunctionInfo> function_info); 107 108 // Note: Returns a new hash table if operation results in expansion. 109 Handle<CompilationCacheTable> TablePut( 110 Handle<String> source, Handle<SharedFunctionInfo> function_info); 111 112 bool HasOrigin(Handle<SharedFunctionInfo> function_info, 113 Handle<Object> name, 114 int line_offset, 115 int column_offset); 116 117 void* script_histogram_; 118 bool script_histogram_initialized_; 119 120 DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheScript); 121 }; 122 123 124 // Sub-cache for eval scripts. Two caches for eval are used. One for eval calls 125 // in global contexts and one for eval calls in other contexts. The cache 126 // considers the following pieces of information when checking for matching 127 // entries: 128 // 1. The source string. 129 // 2. The shared function info of the calling function. 130 // 3. Whether the source should be compiled as strict code or as non-strict 131 // code. 132 // Note: Currently there are clients of CompileEval that always compile 133 // non-strict code even if the calling function is a strict mode function. 134 // More specifically these are the CompileString, DebugEvaluate and 135 // DebugEvaluateGlobal runtime functions. 136 // 4. The start position of the calling scope. 137 class CompilationCacheEval: public CompilationSubCache { 138 public: CompilationCacheEval(Isolate * isolate,int generations)139 CompilationCacheEval(Isolate* isolate, int generations) 140 : CompilationSubCache(isolate, generations) { } 141 142 Handle<SharedFunctionInfo> Lookup(Handle<String> source, 143 Handle<Context> context, 144 LanguageMode language_mode, 145 int scope_position); 146 147 void Put(Handle<String> source, 148 Handle<Context> context, 149 Handle<SharedFunctionInfo> function_info, 150 int scope_position); 151 152 private: 153 MUST_USE_RESULT MaybeObject* TryTablePut( 154 Handle<String> source, 155 Handle<Context> context, 156 Handle<SharedFunctionInfo> function_info, 157 int scope_position); 158 159 // Note: Returns a new hash table if operation results in expansion. 160 Handle<CompilationCacheTable> TablePut( 161 Handle<String> source, 162 Handle<Context> context, 163 Handle<SharedFunctionInfo> function_info, 164 int scope_position); 165 166 DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEval); 167 }; 168 169 170 // Sub-cache for regular expressions. 171 class CompilationCacheRegExp: public CompilationSubCache { 172 public: CompilationCacheRegExp(Isolate * isolate,int generations)173 CompilationCacheRegExp(Isolate* isolate, int generations) 174 : CompilationSubCache(isolate, generations) { } 175 176 Handle<FixedArray> Lookup(Handle<String> source, JSRegExp::Flags flags); 177 178 void Put(Handle<String> source, 179 JSRegExp::Flags flags, 180 Handle<FixedArray> data); 181 private: 182 MUST_USE_RESULT MaybeObject* TryTablePut(Handle<String> source, 183 JSRegExp::Flags flags, 184 Handle<FixedArray> data); 185 186 // Note: Returns a new hash table if operation results in expansion. 187 Handle<CompilationCacheTable> TablePut(Handle<String> source, 188 JSRegExp::Flags flags, 189 Handle<FixedArray> data); 190 191 DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheRegExp); 192 }; 193 194 195 // The compilation cache keeps shared function infos for compiled 196 // scripts and evals. The shared function infos are looked up using 197 // the source string as the key. For regular expressions the 198 // compilation data is cached. 199 class CompilationCache { 200 public: 201 // Finds the script shared function info for a source 202 // string. Returns an empty handle if the cache doesn't contain a 203 // script for the given source string with the right origin. 204 Handle<SharedFunctionInfo> LookupScript(Handle<String> source, 205 Handle<Object> name, 206 int line_offset, 207 int column_offset); 208 209 // Finds the shared function info for a source string for eval in a 210 // given context. Returns an empty handle if the cache doesn't 211 // contain a script for the given source string. 212 Handle<SharedFunctionInfo> LookupEval(Handle<String> source, 213 Handle<Context> context, 214 bool is_global, 215 LanguageMode language_mode, 216 int scope_position); 217 218 // Returns the regexp data associated with the given regexp if it 219 // is in cache, otherwise an empty handle. 220 Handle<FixedArray> LookupRegExp(Handle<String> source, 221 JSRegExp::Flags flags); 222 223 // Associate the (source, kind) pair to the shared function 224 // info. This may overwrite an existing mapping. 225 void PutScript(Handle<String> source, 226 Handle<SharedFunctionInfo> function_info); 227 228 // Associate the (source, context->closure()->shared(), kind) triple 229 // with the shared function info. This may overwrite an existing mapping. 230 void PutEval(Handle<String> source, 231 Handle<Context> context, 232 bool is_global, 233 Handle<SharedFunctionInfo> function_info, 234 int scope_position); 235 236 // Associate the (source, flags) pair to the given regexp data. 237 // This may overwrite an existing mapping. 238 void PutRegExp(Handle<String> source, 239 JSRegExp::Flags flags, 240 Handle<FixedArray> data); 241 242 // Clear the cache - also used to initialize the cache at startup. 243 void Clear(); 244 245 // Remove given shared function info from all caches. 246 void Remove(Handle<SharedFunctionInfo> function_info); 247 248 // GC support. 249 void Iterate(ObjectVisitor* v); 250 void IterateFunctions(ObjectVisitor* v); 251 252 // Notify the cache that a mark-sweep garbage collection is about to 253 // take place. This is used to retire entries from the cache to 254 // avoid keeping them alive too long without using them. 255 void MarkCompactPrologue(); 256 257 // Enable/disable compilation cache. Used by debugger to disable compilation 258 // cache during debugging to make sure new scripts are always compiled. 259 void Enable(); 260 void Disable(); 261 262 private: 263 explicit CompilationCache(Isolate* isolate); 264 ~CompilationCache(); 265 266 HashMap* EagerOptimizingSet(); 267 268 // The number of sub caches covering the different types to cache. 269 static const int kSubCacheCount = 4; 270 IsEnabled()271 bool IsEnabled() { return FLAG_compilation_cache && enabled_; } 272 isolate()273 Isolate* isolate() { return isolate_; } 274 275 Isolate* isolate_; 276 277 CompilationCacheScript script_; 278 CompilationCacheEval eval_global_; 279 CompilationCacheEval eval_contextual_; 280 CompilationCacheRegExp reg_exp_; 281 CompilationSubCache* subcaches_[kSubCacheCount]; 282 283 // Current enable state of the compilation cache. 284 bool enabled_; 285 286 friend class Isolate; 287 288 DISALLOW_COPY_AND_ASSIGN(CompilationCache); 289 }; 290 291 292 } } // namespace v8::internal 293 294 #endif // V8_COMPILATION_CACHE_H_ 295