1 // Copyright 2017 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 #include "src/debug/debug-stack-trace-iterator.h"
6
7 #include "src/api/api-inl.h"
8 #include "src/debug/debug-evaluate.h"
9 #include "src/debug/debug-scope-iterator.h"
10 #include "src/debug/debug.h"
11 #include "src/debug/liveedit.h"
12 #include "src/execution/frames-inl.h"
13 #include "src/execution/isolate.h"
14
15 #if V8_ENABLE_WEBASSEMBLY
16 #include "src/debug/debug-wasm-objects.h"
17 #endif // V8_ENABLE_WEBASSEMBLY
18
19 namespace v8 {
20
Create(v8::Isolate * isolate,int index)21 std::unique_ptr<debug::StackTraceIterator> debug::StackTraceIterator::Create(
22 v8::Isolate* isolate, int index) {
23 return std::unique_ptr<debug::StackTraceIterator>(
24 new internal::DebugStackTraceIterator(
25 reinterpret_cast<internal::Isolate*>(isolate), index));
26 }
27
28 namespace internal {
29
DebugStackTraceIterator(Isolate * isolate,int index)30 DebugStackTraceIterator::DebugStackTraceIterator(Isolate* isolate, int index)
31 : isolate_(isolate),
32 iterator_(isolate, isolate->debug()->break_frame_id()),
33 is_top_frame_(true) {
34 if (iterator_.done()) return;
35 std::vector<FrameSummary> frames;
36 iterator_.frame()->Summarize(&frames);
37 inlined_frame_index_ = static_cast<int>(frames.size());
38 Advance();
39 for (; !Done() && index > 0; --index) Advance();
40 }
41
42 DebugStackTraceIterator::~DebugStackTraceIterator() = default;
43
Done() const44 bool DebugStackTraceIterator::Done() const { return iterator_.done(); }
45
Advance()46 void DebugStackTraceIterator::Advance() {
47 while (true) {
48 --inlined_frame_index_;
49 for (; inlined_frame_index_ >= 0; --inlined_frame_index_) {
50 // Omit functions from native and extension scripts.
51 if (FrameSummary::Get(iterator_.frame(), inlined_frame_index_)
52 .is_subject_to_debugging()) {
53 break;
54 }
55 is_top_frame_ = false;
56 }
57 if (inlined_frame_index_ >= 0) {
58 frame_inspector_.reset(new FrameInspector(
59 iterator_.frame(), inlined_frame_index_, isolate_));
60 break;
61 }
62 is_top_frame_ = false;
63 frame_inspector_.reset();
64 iterator_.Advance();
65 if (iterator_.done()) break;
66 std::vector<FrameSummary> frames;
67 iterator_.frame()->Summarize(&frames);
68 inlined_frame_index_ = static_cast<int>(frames.size());
69 }
70 }
71
GetContextId() const72 int DebugStackTraceIterator::GetContextId() const {
73 DCHECK(!Done());
74 Handle<Object> context = frame_inspector_->GetContext();
75 if (context->IsContext()) {
76 Object value = Context::cast(*context).native_context().debug_context_id();
77 if (value.IsSmi()) return Smi::ToInt(value);
78 }
79 return 0;
80 }
81
GetReceiver() const82 v8::MaybeLocal<v8::Value> DebugStackTraceIterator::GetReceiver() const {
83 DCHECK(!Done());
84 if (frame_inspector_->IsJavaScript() &&
85 frame_inspector_->GetFunction()->shared().kind() ==
86 FunctionKind::kArrowFunction) {
87 // FrameInspector is not able to get receiver for arrow function.
88 // So let's try to fetch it using same logic as is used to retrieve 'this'
89 // during DebugEvaluate::Local.
90 Handle<JSFunction> function = frame_inspector_->GetFunction();
91 Handle<Context> context(function->context(), isolate_);
92 // Arrow function defined in top level function without references to
93 // variables may have NativeContext as context.
94 if (!context->IsFunctionContext()) return v8::MaybeLocal<v8::Value>();
95 ScopeIterator scope_iterator(
96 isolate_, frame_inspector_.get(),
97 ScopeIterator::ReparseStrategy::kFunctionLiteral);
98 // We lookup this variable in function context only when it is used in arrow
99 // function otherwise V8 can optimize it out.
100 if (!scope_iterator.ClosureScopeHasThisReference()) {
101 return v8::MaybeLocal<v8::Value>();
102 }
103 DisallowGarbageCollection no_gc;
104 int slot_index = context->scope_info().ContextSlotIndex(
105 ReadOnlyRoots(isolate_).this_string_handle());
106 if (slot_index < 0) return v8::MaybeLocal<v8::Value>();
107 Handle<Object> value = handle(context->get(slot_index), isolate_);
108 if (value->IsTheHole(isolate_)) return v8::MaybeLocal<v8::Value>();
109 return Utils::ToLocal(value);
110 }
111
112 Handle<Object> value = frame_inspector_->GetReceiver();
113 if (value.is_null() || (value->IsSmi() || !value->IsTheHole(isolate_))) {
114 return Utils::ToLocal(value);
115 }
116 return v8::MaybeLocal<v8::Value>();
117 }
118
GetReturnValue() const119 v8::Local<v8::Value> DebugStackTraceIterator::GetReturnValue() const {
120 CHECK(!Done());
121 #if V8_ENABLE_WEBASSEMBLY
122 if (frame_inspector_ && frame_inspector_->IsWasm()) {
123 return v8::Local<v8::Value>();
124 }
125 #endif // V8_ENABLE_WEBASSEMBLY
126 CHECK_NOT_NULL(iterator_.frame());
127 bool is_optimized = iterator_.frame()->is_optimized();
128 if (is_optimized || !is_top_frame_ ||
129 !isolate_->debug()->IsBreakAtReturn(iterator_.javascript_frame())) {
130 return v8::Local<v8::Value>();
131 }
132 return Utils::ToLocal(isolate_->debug()->return_value_handle());
133 }
134
GetFunctionDebugName() const135 v8::Local<v8::String> DebugStackTraceIterator::GetFunctionDebugName() const {
136 DCHECK(!Done());
137 return Utils::ToLocal(frame_inspector_->GetFunctionName());
138 }
139
GetScript() const140 v8::Local<v8::debug::Script> DebugStackTraceIterator::GetScript() const {
141 DCHECK(!Done());
142 Handle<Object> value = frame_inspector_->GetScript();
143 if (!value->IsScript()) return v8::Local<v8::debug::Script>();
144 return ToApiHandle<debug::Script>(Handle<Script>::cast(value));
145 }
146
GetSourceLocation() const147 debug::Location DebugStackTraceIterator::GetSourceLocation() const {
148 DCHECK(!Done());
149 v8::Local<v8::debug::Script> script = GetScript();
150 if (script.IsEmpty()) return v8::debug::Location();
151 return script->GetSourceLocation(frame_inspector_->GetSourcePosition());
152 }
153
GetFunction() const154 v8::Local<v8::Function> DebugStackTraceIterator::GetFunction() const {
155 DCHECK(!Done());
156 if (!frame_inspector_->IsJavaScript()) return v8::Local<v8::Function>();
157 return Utils::ToLocal(frame_inspector_->GetFunction());
158 }
159
160 std::unique_ptr<v8::debug::ScopeIterator>
GetScopeIterator() const161 DebugStackTraceIterator::GetScopeIterator() const {
162 DCHECK(!Done());
163 #if V8_ENABLE_WEBASSEMBLY
164 if (iterator_.frame()->is_wasm()) {
165 return GetWasmScopeIterator(WasmFrame::cast(iterator_.frame()));
166 }
167 #endif // V8_ENABLE_WEBASSEMBLY
168 return std::make_unique<DebugScopeIterator>(isolate_, frame_inspector_.get());
169 }
170
Evaluate(v8::Local<v8::String> source,bool throw_on_side_effect)171 v8::MaybeLocal<v8::Value> DebugStackTraceIterator::Evaluate(
172 v8::Local<v8::String> source, bool throw_on_side_effect) {
173 DCHECK(!Done());
174 Handle<Object> value;
175
176 i::SafeForInterruptsScope safe_for_interrupt_scope(isolate_);
177 if (!DebugEvaluate::Local(isolate_, iterator_.frame()->id(),
178 inlined_frame_index_, Utils::OpenHandle(*source),
179 throw_on_side_effect)
180 .ToHandle(&value)) {
181 isolate_->OptionalRescheduleException(false);
182 return v8::MaybeLocal<v8::Value>();
183 }
184 return Utils::ToLocal(value);
185 }
186
187 } // namespace internal
188 } // namespace v8
189