1// Copyright 2012 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#ifndef V8_COMPILATION_CACHE_H_
6#define V8_COMPILATION_CACHE_H_
7
8namespace v8 {
9namespace internal {
10
11// The compilation cache consists of several generational sub-caches which uses
12// this class as a base class. A sub-cache contains a compilation cache tables
13// for each generation of the sub-cache. Since the same source code string has
14// different compiled code for scripts and evals, we use separate sub-caches
15// for different compilation modes, to avoid retrieving the wrong result.
16class CompilationSubCache {
17 public:
18  CompilationSubCache(Isolate* isolate, int generations)
19      : isolate_(isolate),
20        generations_(generations) {
21    tables_ = NewArray<Object*>(generations);
22  }
23
24  ~CompilationSubCache() { DeleteArray(tables_); }
25
26  // Index for the first generation in the cache.
27  static const int kFirstGeneration = 0;
28
29  // Get the compilation cache tables for a specific generation.
30  Handle<CompilationCacheTable> GetTable(int generation);
31
32  // Accessors for first generation.
33  Handle<CompilationCacheTable> GetFirstTable() {
34    return GetTable(kFirstGeneration);
35  }
36  void SetFirstTable(Handle<CompilationCacheTable> value) {
37    DCHECK(kFirstGeneration < generations_);
38    tables_[kFirstGeneration] = *value;
39  }
40
41  // Age the sub-cache by evicting the oldest generation and creating a new
42  // young generation.
43  void Age();
44
45  // GC support.
46  void Iterate(ObjectVisitor* v);
47  void IterateFunctions(ObjectVisitor* v);
48
49  // Clear this sub-cache evicting all its content.
50  void Clear();
51
52  // Remove given shared function info from sub-cache.
53  void Remove(Handle<SharedFunctionInfo> function_info);
54
55  // Number of generations in this sub-cache.
56  inline int generations() { return generations_; }
57
58 protected:
59  Isolate* isolate() { return isolate_; }
60
61 private:
62  Isolate* isolate_;
63  int generations_;  // Number of generations.
64  Object** tables_;  // Compilation cache tables - one for each generation.
65
66  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationSubCache);
67};
68
69
70// Sub-cache for scripts.
71class CompilationCacheScript : public CompilationSubCache {
72 public:
73  CompilationCacheScript(Isolate* isolate, int generations);
74
75  Handle<SharedFunctionInfo> Lookup(Handle<String> source,
76                                    Handle<Object> name,
77                                    int line_offset,
78                                    int column_offset,
79                                    bool is_shared_cross_origin,
80                                    Handle<Context> context);
81  void Put(Handle<String> source,
82           Handle<Context> context,
83           Handle<SharedFunctionInfo> function_info);
84
85 private:
86  bool HasOrigin(Handle<SharedFunctionInfo> function_info,
87                 Handle<Object> name,
88                 int line_offset,
89                 int column_offset,
90                 bool is_shared_cross_origin);
91
92  void* script_histogram_;
93  bool script_histogram_initialized_;
94
95  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheScript);
96};
97
98
99// Sub-cache for eval scripts. Two caches for eval are used. One for eval calls
100// in native contexts and one for eval calls in other contexts. The cache
101// considers the following pieces of information when checking for matching
102// entries:
103// 1. The source string.
104// 2. The shared function info of the calling function.
105// 3. Whether the source should be compiled as strict code or as sloppy code.
106//    Note: Currently there are clients of CompileEval that always compile
107//    sloppy code even if the calling function is a strict mode function.
108//    More specifically these are the CompileString, DebugEvaluate and
109//    DebugEvaluateGlobal runtime functions.
110// 4. The start position of the calling scope.
111class CompilationCacheEval: public CompilationSubCache {
112 public:
113  CompilationCacheEval(Isolate* isolate, int generations)
114      : CompilationSubCache(isolate, generations) { }
115
116  MaybeHandle<SharedFunctionInfo> Lookup(Handle<String> source,
117                                         Handle<SharedFunctionInfo> outer_info,
118                                         StrictMode strict_mode,
119                                         int scope_position);
120
121  void Put(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
122           Handle<SharedFunctionInfo> function_info, int scope_position);
123
124 private:
125  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEval);
126};
127
128
129// Sub-cache for regular expressions.
130class CompilationCacheRegExp: public CompilationSubCache {
131 public:
132  CompilationCacheRegExp(Isolate* isolate, int generations)
133      : CompilationSubCache(isolate, generations) { }
134
135  MaybeHandle<FixedArray> Lookup(Handle<String> source, JSRegExp::Flags flags);
136
137  void Put(Handle<String> source,
138           JSRegExp::Flags flags,
139           Handle<FixedArray> data);
140 private:
141  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheRegExp);
142};
143
144
145// The compilation cache keeps shared function infos for compiled
146// scripts and evals. The shared function infos are looked up using
147// the source string as the key. For regular expressions the
148// compilation data is cached.
149class CompilationCache {
150 public:
151  // Finds the script shared function info for a source
152  // string. Returns an empty handle if the cache doesn't contain a
153  // script for the given source string with the right origin.
154  MaybeHandle<SharedFunctionInfo> LookupScript(
155      Handle<String> source, Handle<Object> name, int line_offset,
156      int column_offset, bool is_shared_cross_origin, Handle<Context> context);
157
158  // Finds the shared function info for a source string for eval in a
159  // given context.  Returns an empty handle if the cache doesn't
160  // contain a script for the given source string.
161  MaybeHandle<SharedFunctionInfo> LookupEval(
162      Handle<String> source, Handle<SharedFunctionInfo> outer_info,
163      Handle<Context> context, StrictMode strict_mode, int scope_position);
164
165  // Returns the regexp data associated with the given regexp if it
166  // is in cache, otherwise an empty handle.
167  MaybeHandle<FixedArray> LookupRegExp(
168      Handle<String> source, JSRegExp::Flags flags);
169
170  // Associate the (source, kind) pair to the shared function
171  // info. This may overwrite an existing mapping.
172  void PutScript(Handle<String> source,
173                 Handle<Context> context,
174                 Handle<SharedFunctionInfo> function_info);
175
176  // Associate the (source, context->closure()->shared(), kind) triple
177  // with the shared function info. This may overwrite an existing mapping.
178  void PutEval(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
179               Handle<Context> context,
180               Handle<SharedFunctionInfo> function_info, int scope_position);
181
182  // Associate the (source, flags) pair to the given regexp data.
183  // This may overwrite an existing mapping.
184  void PutRegExp(Handle<String> source,
185                 JSRegExp::Flags flags,
186                 Handle<FixedArray> data);
187
188  // Clear the cache - also used to initialize the cache at startup.
189  void Clear();
190
191  // Remove given shared function info from all caches.
192  void Remove(Handle<SharedFunctionInfo> function_info);
193
194  // GC support.
195  void Iterate(ObjectVisitor* v);
196  void IterateFunctions(ObjectVisitor* v);
197
198  // Notify the cache that a mark-sweep garbage collection is about to
199  // take place. This is used to retire entries from the cache to
200  // avoid keeping them alive too long without using them.
201  void MarkCompactPrologue();
202
203  // Enable/disable compilation cache. Used by debugger to disable compilation
204  // cache during debugging to make sure new scripts are always compiled.
205  void Enable();
206  void Disable();
207
208 private:
209  explicit CompilationCache(Isolate* isolate);
210  ~CompilationCache();
211
212  HashMap* EagerOptimizingSet();
213
214  // The number of sub caches covering the different types to cache.
215  static const int kSubCacheCount = 4;
216
217  bool IsEnabled() { return FLAG_compilation_cache && enabled_; }
218
219  Isolate* isolate() { return isolate_; }
220
221  Isolate* isolate_;
222
223  CompilationCacheScript script_;
224  CompilationCacheEval eval_global_;
225  CompilationCacheEval eval_contextual_;
226  CompilationCacheRegExp reg_exp_;
227  CompilationSubCache* subcaches_[kSubCacheCount];
228
229  // Current enable state of the compilation cache.
230  bool enabled_;
231
232  friend class Isolate;
233
234  DISALLOW_COPY_AND_ASSIGN(CompilationCache);
235};
236
237
238} }  // namespace v8::internal
239
240#endif  // V8_COMPILATION_CACHE_H_
241