1 // Copyright 2015 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_DEBUG_DEBUG_SCOPES_H_
6 #define V8_DEBUG_DEBUG_SCOPES_H_
7 
8 #include "src/debug/debug-frames.h"
9 #include "src/frames.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 class ParseInfo;
15 
16 // Iterate over the actual scopes visible from a stack frame or from a closure.
17 // The iteration proceeds from the innermost visible nested scope outwards.
18 // All scopes are backed by an actual context except the local scope,
19 // which is inserted "artificially" in the context chain.
20 class ScopeIterator {
21  public:
22   enum ScopeType {
23     ScopeTypeGlobal = 0,
24     ScopeTypeLocal,
25     ScopeTypeWith,
26     ScopeTypeClosure,
27     ScopeTypeCatch,
28     ScopeTypeBlock,
29     ScopeTypeScript,
30     ScopeTypeEval,
31     ScopeTypeModule
32   };
33 
34   static const int kScopeDetailsTypeIndex = 0;
35   static const int kScopeDetailsObjectIndex = 1;
36   static const int kScopeDetailsNameIndex = 2;
37   static const int kScopeDetailsStartPositionIndex = 3;
38   static const int kScopeDetailsEndPositionIndex = 4;
39   static const int kScopeDetailsFunctionIndex = 5;
40   static const int kScopeDetailsSize = 6;
41 
42   enum Option { DEFAULT, IGNORE_NESTED_SCOPES, COLLECT_NON_LOCALS };
43 
44   ScopeIterator(Isolate* isolate, FrameInspector* frame_inspector,
45                 Option options = DEFAULT);
46 
47   ScopeIterator(Isolate* isolate, Handle<JSFunction> function);
48   ScopeIterator(Isolate* isolate, Handle<JSGeneratorObject> generator);
49 
50   MUST_USE_RESULT MaybeHandle<JSObject> MaterializeScopeDetails();
51 
52   // More scopes?
Done()53   bool Done() { return context_.is_null(); }
54 
55   // Move to the next scope.
56   void Next();
57 
58   // Return the type of the current scope.
59   ScopeType Type();
60 
61   // Return the JavaScript object with the content of the current scope.
62   MaybeHandle<JSObject> ScopeObject();
63 
64   bool HasContext();
65 
66   // Set variable value and return true on success.
67   bool SetVariableValue(Handle<String> variable_name, Handle<Object> new_value);
68 
69   Handle<ScopeInfo> CurrentScopeInfo();
70 
71   // Return the context for this scope. For the local context there might not
72   // be an actual context.
73   Handle<Context> CurrentContext();
74 
75   // Populate the set with collected non-local variable names.
76   Handle<StringSet> GetNonLocals();
77 
78 #ifdef DEBUG
79   // Debug print of the content of the current scope.
80   void DebugPrint();
81 #endif
82 
83  private:
84   struct ExtendedScopeInfo {
ExtendedScopeInfoExtendedScopeInfo85     ExtendedScopeInfo(Handle<ScopeInfo> info, int start, int end)
86         : scope_info(info), start_position(start), end_position(end) {}
ExtendedScopeInfoExtendedScopeInfo87     explicit ExtendedScopeInfo(Handle<ScopeInfo> info)
88         : scope_info(info), start_position(-1), end_position(-1) {}
89     Handle<ScopeInfo> scope_info;
90     int start_position;
91     int end_position;
is_hiddenExtendedScopeInfo92     bool is_hidden() { return start_position == -1 && end_position == -1; }
93   };
94 
95   Isolate* isolate_;
96   FrameInspector* const frame_inspector_;
97   Handle<Context> context_;
98   List<ExtendedScopeInfo> nested_scope_chain_;
99   Handle<StringSet> non_locals_;
100   bool seen_script_scope_;
101 
GetFrame()102   inline JavaScriptFrame* GetFrame() {
103     return frame_inspector_->GetArgumentsFrame();
104   }
105 
GetFunction()106   inline Handle<JSFunction> GetFunction() {
107     return frame_inspector_->GetFunction();
108   }
109 
110   void RetrieveScopeChain(DeclarationScope* scope);
111 
112   void CollectNonLocals(ParseInfo* info, DeclarationScope* scope);
113 
114   void UnwrapEvaluationContext();
115 
116   MUST_USE_RESULT MaybeHandle<JSObject> MaterializeScriptScope();
117   MUST_USE_RESULT MaybeHandle<JSObject> MaterializeLocalScope();
118   MUST_USE_RESULT MaybeHandle<JSObject> MaterializeModuleScope();
119   Handle<JSObject> MaterializeClosure();
120   Handle<JSObject> MaterializeCatchScope();
121   Handle<JSObject> MaterializeInnerScope();
122   Handle<JSObject> WithContextExtension();
123 
124   bool SetLocalVariableValue(Handle<String> variable_name,
125                              Handle<Object> new_value);
126   bool SetInnerScopeVariableValue(Handle<String> variable_name,
127                                   Handle<Object> new_value);
128   bool SetClosureVariableValue(Handle<String> variable_name,
129                                Handle<Object> new_value);
130   bool SetScriptVariableValue(Handle<String> variable_name,
131                               Handle<Object> new_value);
132   bool SetCatchVariableValue(Handle<String> variable_name,
133                              Handle<Object> new_value);
134 
135   // Helper functions.
136   bool SetParameterValue(Handle<ScopeInfo> scope_info, JavaScriptFrame* frame,
137                          Handle<String> parameter_name,
138                          Handle<Object> new_value);
139   bool SetStackVariableValue(Handle<ScopeInfo> scope_info,
140                              Handle<String> variable_name,
141                              Handle<Object> new_value);
142   bool SetContextVariableValue(Handle<ScopeInfo> scope_info,
143                                Handle<Context> context,
144                                Handle<String> variable_name,
145                                Handle<Object> new_value);
146 
147   void CopyContextLocalsToScopeObject(Handle<ScopeInfo> scope_info,
148                                       Handle<Context> context,
149                                       Handle<JSObject> scope_object);
150   void CopyModuleVarsToScopeObject(Handle<ScopeInfo> scope_info,
151                                    Handle<Context> context,
152                                    Handle<JSObject> scope_object);
153   void CopyContextExtensionToScopeObject(Handle<Context> context,
154                                          Handle<JSObject> scope_object,
155                                          KeyCollectionMode mode);
156 
157   // Get the chain of nested scopes within this scope for the source statement
158   // position. The scopes will be added to the list from the outermost scope to
159   // the innermost scope. Only nested block, catch or with scopes are tracked
160   // and will be returned, but no inner function scopes.
161   void GetNestedScopeChain(Isolate* isolate, Scope* scope,
162                            int statement_position);
163 
164   DISALLOW_IMPLICIT_CONSTRUCTORS(ScopeIterator);
165 };
166 
167 }  // namespace internal
168 }  // namespace v8
169 
170 #endif  // V8_DEBUG_DEBUG_SCOPES_H_
171