[wasm] Provide better stack traces for asm.js code

src/messages.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/messages.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/execution.h"
@@ skipping 193 matching lines @@
   Handle<String> result = JSFunction::GetName(function_);
   if (result->length() != 0) return result;
 
   if (HasScript() &&
       GetScript()->compilation_type() == Script::COMPILATION_TYPE_EVAL) {
     return isolate_->factory()->eval_string();
   }
   return isolate_->factory()->null_value();
 }
 
-Handle<Object> JSStackFrame::GetScriptNameOrSourceUrl() {
-  if (!HasScript()) return isolate_->factory()->null_value();
-  Handle<Script> script = GetScript();
-  Object* source_url = script->source_url();
-  return (source_url->IsString()) ? handle(source_url, isolate_)
-                                  : handle(script->name(), isolate_);
-}
-
 namespace {
 
 bool CheckMethodName(Isolate* isolate, Handle<JSObject> obj, Handle<Name> name,
                      Handle<JSFunction> fun,
                      LookupIterator::Configuration config) {
   LookupIterator iter =
       LookupIterator::PropertyOrElement(isolate, obj, name, config);
   if (iter.state() == LookupIterator::DATA) {
     return iter.GetDataValue().is_identical_to(fun);
   } else if (iter.state() == LookupIterator::ACCESSOR) {
     Handle<Object> accessors = iter.GetAccessors();
     if (accessors->IsAccessorPair()) {
       Handle<AccessorPair> pair = Handle<AccessorPair>::cast(accessors);
       return pair->getter() == *fun || pair->setter() == *fun;
     }
   }
   return false;
 }
 
+Handle<Object> ScriptNameOrSourceUrl(Handle<Script> script, Isolate* isolate) {
+  Object* name_or_url = script->source_url();
+  if (!name_or_url->IsString()) name_or_url = script->name();
+  return handle(name_or_url, isolate);
+}
+
 }  // namespace
 
+Handle<Object> JSStackFrame::GetScriptNameOrSourceUrl() {
+  if (!HasScript()) return isolate_->factory()->null_value();
+  return ScriptNameOrSourceUrl(GetScript(), isolate_);
+}
+
 Handle<Object> JSStackFrame::GetMethodName() {
   if (receiver_->IsNull(isolate_) || receiver_->IsUndefined(isolate_)) {
     return isolate_->factory()->null_value();
   }
 
   Handle<JSReceiver> receiver =
       Object::ToObject(isolate_, receiver_).ToHandleChecked();
   if (!receiver->IsJSObject()) {
     return isolate_->factory()->null_value();
   }
@@ skipping 195 matching lines @@
                                   isolate_->factory()->constructor_string());
   return constructor.is_identical_to(function_);
 }
 
 namespace {
 
 bool IsNonEmptyString(Handle<Object> object) {
   return (object->IsString() && String::cast(*object)->length() > 0);
 }
 
-void AppendFileLocation(Isolate* isolate, JSStackFrame* call_site,
+void AppendFileLocation(Isolate* isolate, StackFrameBase* call_site,
                         IncrementalStringBuilder* builder) {
   if (call_site->IsNative()) {
     builder->AppendCString("native");
     return;
   }
 
   Handle<Object> file_name = call_site->GetScriptNameOrSourceUrl();
   if (!file_name->IsString() && call_site->IsEval()) {
     Handle<Object> eval_origin = call_site->GetEvalOrigin();
     DCHECK(eval_origin->IsString());
@@ skipping 191 matching lines @@
 }
 
 int WasmStackFrame::GetPosition() const {
   return (offset_ < 0) ? (-1 - offset_) : code_->SourcePosition(offset_);
 }
 
 Handle<Object> WasmStackFrame::Null() const {
   return isolate_->factory()->null_value();
 }
 
+Handle<Object> AsmJsWasmStackFrame::GetReceiver() const {
+  return isolate_->global_object();

[jgruber, 2016/10/11 19:07:40]

As far I understand, the global object should never be exposed to the user, and
instead the global proxy should be passed. Maybe it'd be a good idea to ask e.g.
Toon about this.

[Clemens Hammacher, 2016/10/12 07:37:18]

You are right. Fixed it.

+}
+
+Handle<Object> AsmJsWasmStackFrame::GetFunction() const {
+  // TODO(clemensh): Return lazily created JSFunction.
+  return Null();
+}
+
+Handle<Object> AsmJsWasmStackFrame::GetFileName() {
+  Handle<Script> script =
+      wasm::GetAsmWasmScript(Handle<JSObject>::cast(wasm_obj_));
+  return handle(script->name(), isolate_);
+}
+
+Handle<Object> AsmJsWasmStackFrame::GetFunctionName() {
+  return wasm::GetWasmFunctionNameOrNull(isolate_, wasm_obj_, wasm_func_index_);
+}
+
+Handle<Object> AsmJsWasmStackFrame::GetScriptNameOrSourceUrl() {
+  Handle<Script> script =
+      wasm::GetAsmWasmScript(Handle<JSObject>::cast(wasm_obj_));
+  return ScriptNameOrSourceUrl(script, isolate_);
+}
+
+int AsmJsWasmStackFrame::GetPosition() const {
+  DCHECK_LE(0, offset_);
+  int byte_offset = code_->SourcePosition(offset_);
+  return wasm::GetAsmWasmSourcePosition(Handle<JSObject>::cast(wasm_obj_),
+                                        wasm_func_index_, byte_offset);
+}
+
+int AsmJsWasmStackFrame::GetLineNumber() {
+  DCHECK_LE(0, GetPosition());
+  Handle<Script> script =
+      wasm::GetAsmWasmScript(Handle<JSObject>::cast(wasm_obj_));
+  return Script::GetLineNumber(script, GetPosition()) + 1;
+}
+
+int AsmJsWasmStackFrame::GetColumnNumber() {
+  DCHECK_LE(0, GetPosition());
+  Handle<Script> script =
+      wasm::GetAsmWasmScript(Handle<JSObject>::cast(wasm_obj_));
+  return Script::GetColumnNumber(script, GetPosition()) + 1;
+}
+
+MaybeHandle<String> AsmJsWasmStackFrame::ToString() {
+  // The string should look exactly as the respective javascript frame string.
+  // Keep this method in line to JSStackFrame::ToString().
+
+  IncrementalStringBuilder builder(isolate_);
+
+  Handle<Object> function_name = GetFunctionName();
+
+  if (IsNonEmptyString(function_name)) {
+    builder.AppendString(Handle<String>::cast(function_name));
+    builder.AppendCString(" (");
+  }
+
+  AppendFileLocation(isolate_, this, &builder);
+
+  if (IsNonEmptyString(function_name)) builder.AppendCString(")");
+
+  RETURN_RESULT(isolate_, builder.Finish(), String);
+}
+
 FrameArrayIterator::FrameArrayIterator(Isolate* isolate,
                                        Handle<FrameArray> array, int frame_ix)
     : isolate_(isolate), array_(array), next_frame_ix_(frame_ix) {}
 
 bool FrameArrayIterator::HasNext() const {
   return (next_frame_ix_ < array_->FrameCount());
 }
 
 void FrameArrayIterator::Next() { next_frame_ix_++; }
 
 StackFrameBase* FrameArrayIterator::Frame() {
   DCHECK(HasNext());
   const int flags = array_->Flags(next_frame_ix_)->value();
   const bool is_js_frame = (flags & FrameArray::kIsWasmFrame) == 0;
   if (is_js_frame) {
     js_frame_.FromFrameArray(isolate_, array_, next_frame_ix_);
     return &js_frame_;
-  } else {
-    wasm_frame_.FromFrameArray(isolate_, array_, next_frame_ix_);
-    return &wasm_frame_;
   }
+  const bool is_asm_wasm_frame = (flags & FrameArray::kIsAsmWasmFrame) != 0;

[jgruber, 2016/10/11 19:07:40]

Can we make this a switch on flags & (kIsWasmFrame | kIsAsmWasmFrame), and
ensure that we fall into exactly one of the three possible cases?

[Clemens Hammacher, 2016/10/12 07:37:18]

Done.

+  if (is_asm_wasm_frame) {
+    asm_wasm_frame_.FromFrameArray(isolate_, array_, next_frame_ix_);
+    return &asm_wasm_frame_;
+  }
+  wasm_frame_.FromFrameArray(isolate_, array_, next_frame_ix_);
+  return &wasm_frame_;
 }
 
 namespace {
 
 MaybeHandle<Object> ConstructCallSite(Isolate* isolate,
                                       Handle<FrameArray> frame_array,
                                       int frame_index) {
   Handle<JSFunction> target =
       handle(isolate->native_context()->callsite_function(), isolate);
 
@@ skipping 398 matching lines @@
   DCHECK(mode != SKIP_UNTIL_SEEN);
 
   Handle<Object> no_caller;
   Handle<String> msg = FormatMessage(isolate, template_index, arg0, arg1, arg2);
   return ErrorUtils::Construct(isolate, constructor, constructor, msg, mode,
                                no_caller, false);
 }
 
 }  // namespace internal
 }  // namespace v8