V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
compilation-cache.h
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 
8 #include "src/allocation.h"
9 #include "src/objects/compilation-cache.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 template <typename T>
15 class Handle;
16 
17 class RootVisitor;
18 
19 // The compilation cache consists of several generational sub-caches which uses
20 // this class as a base class. A sub-cache contains a compilation cache tables
21 // for each generation of the sub-cache. Since the same source code string has
22 // different compiled code for scripts and evals, we use separate sub-caches
23 // for different compilation modes, to avoid retrieving the wrong result.
25  public:
26  CompilationSubCache(Isolate* isolate, int generations)
27  : isolate_(isolate),
28  generations_(generations) {
29  tables_ = NewArray<Object*>(generations);
30  }
31 
32  ~CompilationSubCache() { DeleteArray(tables_); }
33 
34  // Index for the first generation in the cache.
35  static const int kFirstGeneration = 0;
36 
37  // Get the compilation cache tables for a specific generation.
38  Handle<CompilationCacheTable> GetTable(int generation);
39 
40  // Accessors for first generation.
41  Handle<CompilationCacheTable> GetFirstTable() {
42  return GetTable(kFirstGeneration);
43  }
44  void SetFirstTable(Handle<CompilationCacheTable> value) {
45  DCHECK_LT(kFirstGeneration, generations_);
46  tables_[kFirstGeneration] = *value;
47  }
48 
49  // Age the sub-cache by evicting the oldest generation and creating a new
50  // young generation.
51  void Age();
52 
53  // GC support.
54  void Iterate(RootVisitor* v);
55 
56  // Clear this sub-cache evicting all its content.
57  void Clear();
58 
59  // Remove given shared function info from sub-cache.
60  void Remove(Handle<SharedFunctionInfo> function_info);
61 
62  // Number of generations in this sub-cache.
63  inline int generations() { return generations_; }
64 
65  protected:
66  Isolate* isolate() { return isolate_; }
67 
68  private:
69  Isolate* isolate_;
70  int generations_; // Number of generations.
71  Object** tables_; // Compilation cache tables - one for each generation.
72 
73  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationSubCache);
74 };
75 
76 
77 // Sub-cache for scripts.
79  public:
80  explicit CompilationCacheScript(Isolate* isolate);
81 
84  int line_offset, int column_offset,
85  ScriptOriginOptions resource_options,
86  Handle<Context> native_context,
87  LanguageMode language_mode);
88 
89  void Put(Handle<String> source, Handle<Context> context,
90  LanguageMode language_mode,
91  Handle<SharedFunctionInfo> function_info);
92 
93  private:
94  bool HasOrigin(Handle<SharedFunctionInfo> function_info,
95  MaybeHandle<Object> name, int line_offset, int column_offset,
96  ScriptOriginOptions resource_options);
97 
98  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheScript);
99 };
100 
101 
102 // Sub-cache for eval scripts. Two caches for eval are used. One for eval calls
103 // in native contexts and one for eval calls in other contexts. The cache
104 // considers the following pieces of information when checking for matching
105 // entries:
106 // 1. The source string.
107 // 2. The shared function info of the calling function.
108 // 3. Whether the source should be compiled as strict code or as sloppy code.
109 // Note: Currently there are clients of CompileEval that always compile
110 // sloppy code even if the calling function is a strict mode function.
111 // More specifically these are the CompileString, DebugEvaluate and
112 // DebugEvaluateGlobal runtime functions.
113 // 4. The start position of the calling scope.
115  public:
116  explicit CompilationCacheEval(Isolate* isolate)
117  : CompilationSubCache(isolate, 1) {}
118 
119  InfoCellPair Lookup(Handle<String> source,
120  Handle<SharedFunctionInfo> outer_info,
121  Handle<Context> native_context,
122  LanguageMode language_mode, int position);
123 
124  void Put(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
125  Handle<SharedFunctionInfo> function_info,
126  Handle<Context> native_context, Handle<FeedbackCell> feedback_cell,
127  int position);
128 
129  private:
130  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheEval);
131 };
132 
133 
134 // Sub-cache for regular expressions.
136  public:
137  CompilationCacheRegExp(Isolate* isolate, int generations)
138  : CompilationSubCache(isolate, generations) { }
139 
141 
142  void Put(Handle<String> source,
143  JSRegExp::Flags flags,
144  Handle<FixedArray> data);
145  private:
146  DISALLOW_IMPLICIT_CONSTRUCTORS(CompilationCacheRegExp);
147 };
148 
149 // The compilation cache keeps shared function infos for compiled
150 // scripts and evals. The shared function infos are looked up using
151 // the source string as the key. For regular expressions the
152 // compilation data is cached.
154  public:
155  // Finds the script shared function info for a source
156  // string. Returns an empty handle if the cache doesn't contain a
157  // script for the given source string with the right origin.
158  MaybeHandle<SharedFunctionInfo> LookupScript(
159  Handle<String> source, MaybeHandle<Object> name, int line_offset,
160  int column_offset, ScriptOriginOptions resource_options,
161  Handle<Context> native_context, LanguageMode language_mode);
162 
163  // Finds the shared function info for a source string for eval in a
164  // given context. Returns an empty handle if the cache doesn't
165  // contain a script for the given source string.
166  InfoCellPair LookupEval(Handle<String> source,
167  Handle<SharedFunctionInfo> outer_info,
168  Handle<Context> context, LanguageMode language_mode,
169  int position);
170 
171  // Returns the regexp data associated with the given regexp if it
172  // is in cache, otherwise an empty handle.
173  MaybeHandle<FixedArray> LookupRegExp(
174  Handle<String> source, JSRegExp::Flags flags);
175 
176  // Associate the (source, kind) pair to the shared function
177  // info. This may overwrite an existing mapping.
178  void PutScript(Handle<String> source, Handle<Context> native_context,
179  LanguageMode language_mode,
180  Handle<SharedFunctionInfo> function_info);
181 
182  // Associate the (source, context->closure()->shared(), kind) triple
183  // with the shared function info. This may overwrite an existing mapping.
184  void PutEval(Handle<String> source, Handle<SharedFunctionInfo> outer_info,
185  Handle<Context> context,
186  Handle<SharedFunctionInfo> function_info,
187  Handle<FeedbackCell> feedback_cell, int position);
188 
189  // Associate the (source, flags) pair to the given regexp data.
190  // This may overwrite an existing mapping.
191  void PutRegExp(Handle<String> source,
192  JSRegExp::Flags flags,
193  Handle<FixedArray> data);
194 
195  // Clear the cache - also used to initialize the cache at startup.
196  void Clear();
197 
198  // Remove given shared function info from all caches.
199  void Remove(Handle<SharedFunctionInfo> function_info);
200 
201  // GC support.
202  void Iterate(RootVisitor* v);
203 
204  // Notify the cache that a mark-sweep garbage collection is about to
205  // take place. This is used to retire entries from the cache to
206  // avoid keeping them alive too long without using them.
207  void MarkCompactPrologue();
208 
209  // Enable/disable compilation cache. Used by debugger to disable compilation
210  // cache during debugging to make sure new scripts are always compiled.
211  void Enable();
212  void Disable();
213 
214  private:
215  explicit CompilationCache(Isolate* isolate);
216  ~CompilationCache() = default;
217 
218  base::HashMap* EagerOptimizingSet();
219 
220  // The number of sub caches covering the different types to cache.
221  static const int kSubCacheCount = 4;
222 
223  bool IsEnabled() const { return FLAG_compilation_cache && enabled_; }
224 
225  Isolate* isolate() const { return isolate_; }
226 
227  Isolate* isolate_;
228 
229  CompilationCacheScript script_;
230  CompilationCacheEval eval_global_;
231  CompilationCacheEval eval_contextual_;
232  CompilationCacheRegExp reg_exp_;
233  CompilationSubCache* subcaches_[kSubCacheCount];
234 
235  // Current enable state of the compilation cache.
236  bool enabled_;
237 
238  friend class Isolate;
239 
240  DISALLOW_COPY_AND_ASSIGN(CompilationCache);
241 };
242 
243 
244 } // namespace internal
245 } // namespace v8
246 
247 #endif // V8_COMPILATION_CACHE_H_
Definition: libplatform.h:13