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//
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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
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11//       with the distribution.
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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
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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,
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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
31namespace v8 {
32namespace 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.
39class CompilationSubCache {
40 public:
41  CompilationSubCache(Isolate* isolate, int generations)
42      : isolate_(isolate),
43        generations_(generations) {
44    tables_ = NewArray<Object*>(generations);
45  }
46
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.
56  Handle<CompilationCacheTable> GetFirstTable() {
57    return GetTable(kFirstGeneration);
58  }
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.
79  inline int generations() { return generations_; }
80
81 protected:
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.
94class 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.
137class CompilationCacheEval: public CompilationSubCache {
138 public:
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.
171class CompilationCacheRegExp: public CompilationSubCache {
172 public:
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.
199class 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
271  bool IsEnabled() { return FLAG_compilation_cache && enabled_; }
272
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