Revert of Use a custom Struct for stack trace storage (patchset #4 id:60001 of...

Revert of Use a custom Struct for stack trace storage (patchset #4 id:60001 of https://codereview.chromium.org/2230953002/ )

Reason for revert:
Performance regressions in Gameboy, Life, CodeLoad and others. See crbug.com/638210.

Original issue's description:
> Refactor data structures for simple stack traces
>
> Simple stack traces are captured through Isolate::CaptureSimpleStackTrace.
> Captured frames are stored in a FixedArray, which in turn is stored as a
> property (using a private symbol) on the error object itself. Actual formatting
> of the textual stack trace is done lazily when the user reads the stack
> property of the error object.
>
> This would involve many conversions back and forth between index-encoded raw
> data (receiver, function, offset and code), JS CallSite objects, and C++
> CallSite objects.
>
> This commit refactors the C++ CallSite class into a Struct class called
> StackTraceFrame, which is the new single point of truth frame information.
> Isolate::CaptureSimpleStackTrace stores an array of StackTraceFrames, and JS
> CallSite objects (now created only when the user specifies custom stack trace
> formatting through Error.prepareStackTrace) internally only store a reference
> to a StackTraceFrame.
>
> BUG=
>
> Committed: https://crrev.com/b4c1aefb9c369f1a33a6ca94a5de9b06ea4bf5c4
> Cr-Commit-Position: refs/heads/master@{#38645}

TBR=yangguo@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Review-Url: https://codereview.chromium.org/2252783007
Cr-Commit-Position: refs/heads/master@{#38700}

include/v8.h

@@ -7623,8 +7623,8 @@ class Internals {
   static const int kNodeIsPartiallyDependentShift = 4;
   static const int kNodeIsActiveShift = 4;
 
-  static const int kJSObjectType = 0xb8;
-  static const int kJSApiObjectType = 0xb7;
+  static const int kJSObjectType = 0xb7;
+  static const int kJSApiObjectType = 0xb6;
   static const int kFirstNonstringType = 0x80;
   static const int kOddballType = 0x83;
   static const int kForeignType = 0x87;

src/builtins/builtins-callsite.cc

@@ -11,22 +11,15 @@
 namespace v8 {
 namespace internal {
 
-#define CHECK_CALLSITE(recv, method)                                           \
-  CHECK_RECEIVER(JSObject, recv, method);                                      \
-  Handle<StackTraceFrame> frame;                                               \
-  {                                                                            \
-    Handle<Object> frame_obj;                                                  \
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(                                        \
-        isolate, frame_obj,                                                    \
-        JSObject::GetProperty(recv,                                            \
-                              isolate->factory()->call_site_frame_symbol()));  \
-    if (!frame_obj->IsStackTraceFrame()) {                                     \
-      THROW_NEW_ERROR_RETURN_FAILURE(                                          \
-          isolate, NewTypeError(MessageTemplate::kCallSiteMethod,              \
-                                isolate->factory()->NewStringFromAsciiChecked( \
-                                    method)));                                 \
-    }                                                                          \
-    frame = Handle<StackTraceFrame>::cast(frame_obj);                          \
+#define CHECK_CALLSITE(recv, method)                                          \
+  CHECK_RECEIVER(JSObject, recv, method);                                     \
+  if (!JSReceiver::HasOwnProperty(                                            \
+           recv, isolate->factory()->call_site_position_symbol())             \
+           .FromMaybe(false)) {                                               \
+    THROW_NEW_ERROR_RETURN_FAILURE(                                           \
+        isolate,                                                              \
+        NewTypeError(MessageTemplate::kCallSiteMethod,                        \
+                     isolate->factory()->NewStringFromAsciiChecked(method))); \
   }
 
 namespace {
@@ -41,107 +34,167 @@ Object* PositiveNumberOrNull(int value, Isolate* isolate) {
 BUILTIN(CallSitePrototypeGetColumnNumber) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getColumnNumber");
-  return PositiveNumberOrNull(frame->GetColumnNumber(), isolate);
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return PositiveNumberOrNull(call_site.GetColumnNumber(), isolate);
 }
 
 BUILTIN(CallSitePrototypeGetEvalOrigin) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getEvalOrigin");
-  return *frame->GetEvalOrigin();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetEvalOrigin();
 }
 
 BUILTIN(CallSitePrototypeGetFileName) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getFileName");
-  return *frame->GetFileName();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetFileName();
+}
+
+namespace {
+
+bool CallSiteIsStrict(Isolate* isolate, Handle<JSObject> receiver) {
+  Handle<Object> strict;
+  Handle<Symbol> symbol = isolate->factory()->call_site_strict_symbol();
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, strict,
+                                     JSObject::GetProperty(receiver, symbol));
+  return strict->BooleanValue();
 }
 
+}  // namespace
+
 BUILTIN(CallSitePrototypeGetFunction) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getFunction");
 
-  if (frame->IsStrict() || frame->IsWasmFrame()) {
+  if (CallSiteIsStrict(isolate, recv))
     return *isolate->factory()->undefined_value();
-  }
 
-  return frame->function();
+  Handle<Symbol> symbol = isolate->factory()->call_site_function_symbol();
+  RETURN_RESULT_OR_FAILURE(isolate, JSObject::GetProperty(recv, symbol));
 }
 
 BUILTIN(CallSitePrototypeGetFunctionName) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getFunctionName");
-  return *frame->GetFunctionName();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetFunctionName();
 }
 
 BUILTIN(CallSitePrototypeGetLineNumber) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getLineNumber");
-  return PositiveNumberOrNull(frame->GetLineNumber(), isolate);
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+
+  int line_number = call_site.IsWasm() ? call_site.wasm_func_index()
+                                       : call_site.GetLineNumber();
+  return PositiveNumberOrNull(line_number, isolate);
 }
 
 BUILTIN(CallSitePrototypeGetMethodName) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getMethodName");
-  return *frame->GetMethodName();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetMethodName();
 }
 
 BUILTIN(CallSitePrototypeGetPosition) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getPosition");
-  return Smi::FromInt(frame->GetPosition());
+
+  Handle<Symbol> symbol = isolate->factory()->call_site_position_symbol();
+  RETURN_RESULT_OR_FAILURE(isolate, JSObject::GetProperty(recv, symbol));
 }
 
 BUILTIN(CallSitePrototypeGetScriptNameOrSourceURL) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getScriptNameOrSourceUrl");
-  return *frame->GetScriptNameOrSourceUrl();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetScriptNameOrSourceUrl();
 }
 
 BUILTIN(CallSitePrototypeGetThis) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getThis");
 
-  if (frame->IsStrict() || frame->ForceConstructor() || frame->IsWasmFrame()) {
+  if (CallSiteIsStrict(isolate, recv))
+    return *isolate->factory()->undefined_value();
+
+  Handle<Object> receiver;
+  Handle<Symbol> symbol = isolate->factory()->call_site_receiver_symbol();
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, receiver,
+                                     JSObject::GetProperty(recv, symbol));
+
+  if (*receiver == isolate->heap()->call_site_constructor_symbol())
     return *isolate->factory()->undefined_value();
-  }
 
-  return frame->receiver();
+  return *receiver;
 }
 
 BUILTIN(CallSitePrototypeGetTypeName) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "getTypeName");
-  return *frame->GetTypeName();
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return *call_site.GetTypeName();
 }
 
 BUILTIN(CallSitePrototypeIsConstructor) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "isConstructor");
-  return isolate->heap()->ToBoolean(frame->IsConstructor());
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return isolate->heap()->ToBoolean(call_site.IsConstructor());
 }
 
 BUILTIN(CallSitePrototypeIsEval) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "isEval");
-  return isolate->heap()->ToBoolean(frame->IsEval());
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return isolate->heap()->ToBoolean(call_site.IsEval());
 }
 
 BUILTIN(CallSitePrototypeIsNative) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "isNative");
-  return isolate->heap()->ToBoolean(frame->IsNative());
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return isolate->heap()->ToBoolean(call_site.IsNative());
 }
 
 BUILTIN(CallSitePrototypeIsToplevel) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "isToplevel");
-  return isolate->heap()->ToBoolean(frame->IsToplevel());
+
+  CallSite call_site(isolate, recv);
+  CHECK(call_site.IsJavaScript() || call_site.IsWasm());
+  return isolate->heap()->ToBoolean(call_site.IsToplevel());
 }
 
 BUILTIN(CallSitePrototypeToString) {
   HandleScope scope(isolate);
   CHECK_CALLSITE(recv, "toString");
-  return *frame->ToString();
+  RETURN_RESULT_OR_FAILURE(isolate, CallSiteUtils::ToString(isolate, recv));
 }
 
 #undef CHECK_CALLSITE

src/execution.cc

@@ -434,6 +434,31 @@ void StackGuard::InitThread(const ExecutionAccess& lock) {
 // --- C a l l s   t o   n a t i v e s ---
 
 
+Handle<String> Execution::GetStackTraceLine(Handle<Object> recv,
+                                            Handle<JSFunction> fun,
+                                            Handle<Object> pos,
+                                            Handle<Object> is_global) {
+  Isolate* isolate = fun->GetIsolate();
+  Handle<Object> strict_mode = isolate->factory()->ToBoolean(false);
+
+  MaybeHandle<Object> maybe_callsite =
+      CallSiteUtils::Construct(isolate, recv, fun, pos, strict_mode);
+  if (maybe_callsite.is_null()) {
+    isolate->clear_pending_exception();
+    return isolate->factory()->empty_string();
+  }
+
+  MaybeHandle<String> maybe_to_string =
+      CallSiteUtils::ToString(isolate, maybe_callsite.ToHandleChecked());
+  if (maybe_to_string.is_null()) {
+    isolate->clear_pending_exception();
+    return isolate->factory()->empty_string();
+  }
+
+  return maybe_to_string.ToHandleChecked();
+}
+
+
 void StackGuard::HandleGCInterrupt() {
   if (CheckAndClearInterrupt(GC_REQUEST)) {
     isolate_->heap()->HandleGCRequest();

src/execution.h

@@ -48,6 +48,11 @@ class Execution final : public AllStatic {
                                      Handle<Object> receiver, int argc,
                                      Handle<Object> argv[],
                                      MaybeHandle<Object>* exception_out = NULL);
+
+  static Handle<String> GetStackTraceLine(Handle<Object> recv,
+                                          Handle<JSFunction> fun,
+                                          Handle<Object> pos,
+                                          Handle<Object> is_global);
 };
 
 

src/factory.cc

@@ -917,13 +917,6 @@ Handle<Script> Factory::NewScript(Handle<String> source) {
   return script;
 }
 
-Handle<StackTraceFrame> Factory::NewStackTraceFrame() {
-  Handle<StackTraceFrame> frame =
-      Handle<StackTraceFrame>::cast(NewStruct(STACK_TRACE_FRAME_TYPE));
-  frame->set_flags(0);
-  frame->set_offset(0);
-  return frame;
-}
 
 Handle<Foreign> Factory::NewForeign(Address addr, PretenureFlag pretenure) {
   CALL_HEAP_FUNCTION(isolate(),

src/factory.h

@@ -292,8 +292,6 @@ class Factory final {
 
   Handle<Script> NewScript(Handle<String> source);
 
-  Handle<StackTraceFrame> NewStackTraceFrame();
-
   // Foreign objects are pretenured when allocated by the bootstrapper.
   Handle<Foreign> NewForeign(Address addr,
                              PretenureFlag pretenure = NOT_TENURED);

src/heap-symbols.h

@@ -161,7 +161,13 @@
   V(array_iteration_kind_symbol)            \
   V(array_iterator_next_symbol)             \
   V(array_iterator_object_symbol)           \
-  V(call_site_frame_symbol)                 \
+  V(call_site_constructor_symbol)           \
+  V(call_site_function_symbol)              \
+  V(call_site_position_symbol)              \
+  V(call_site_receiver_symbol)              \
+  V(call_site_strict_symbol)                \
+  V(call_site_wasm_obj_symbol)              \
+  V(call_site_wasm_func_index_symbol)       \
   V(class_end_position_symbol)              \
   V(class_start_position_symbol)            \
   V(detailed_stack_trace_symbol)            \

src/messages.h

@@ -42,6 +42,40 @@ class MessageLocation {
   Handle<JSFunction> function_;
 };
 
+
+class CallSite {
+ public:
+  CallSite(Isolate* isolate, Handle<JSObject> call_site_obj);
+
+  Handle<Object> GetFileName();
+  Handle<Object> GetFunctionName();
+  Handle<Object> GetScriptNameOrSourceUrl();
+  Handle<Object> GetMethodName();
+  Handle<Object> GetTypeName();
+  Handle<Object> GetEvalOrigin();
+  // Return 1-based line number, including line offset.
+  int GetLineNumber();
+  // Return 1-based column number, including column offset if first line.
+  int GetColumnNumber();
+  bool IsNative();
+  bool IsToplevel();
+  bool IsEval();
+  bool IsConstructor();
+
+  bool IsJavaScript() { return !fun_.is_null(); }
+  bool IsWasm() { return !wasm_obj_.is_null(); }
+
+  int wasm_func_index() const { return wasm_func_index_; }
+
+ private:
+  Isolate* isolate_;
+  Handle<Object> receiver_;
+  Handle<JSFunction> fun_;
+  int32_t pos_ = -1;
+  Handle<JSObject> wasm_obj_;
+  uint32_t wasm_func_index_ = static_cast<uint32_t>(-1);
+};
+
 // Determines how stack trace collection skips frames.
 enum FrameSkipMode {
   // Unconditionally skips the first frame. Used e.g. when the Error constructor
@@ -73,6 +107,16 @@ class ErrorUtils : public AllStatic {
                                               Handle<Object> stack_trace);
 };
 
+class CallSiteUtils : public AllStatic {
+ public:
+  static MaybeHandle<Object> Construct(Isolate* isolate,
+                                       Handle<Object> receiver,
+                                       Handle<Object> fun, Handle<Object> pos,
+                                       Handle<Object> strict_mode);
+
+  static MaybeHandle<String> ToString(Isolate* isolate, Handle<Object> recv);
+};
+
 #define MESSAGE_TEMPLATES(T)                                                   \
   /* Error */                                                                  \
   T(None, "")                                                                  \

src/objects-debug.cc

@@ -1016,10 +1016,6 @@ void Script::ScriptVerify() {
   VerifyPointer(line_ends());
 }
 
-void StackTraceFrame::StackTraceFrameVerify() {
-  CHECK(IsStackTraceFrame());
-  VerifyPointer(abstract_code());
-}
 
 void NormalizedMapCache::NormalizedMapCacheVerify() {
   FixedArray::cast(this)->FixedArrayVerify();

src/objects-inl.h

@@ -5818,29 +5818,6 @@ void Script::set_origin_options(ScriptOriginOptions origin_options) {
             (origin_options.Flags() << kOriginOptionsShift));
 }
 
-SMI_ACCESSORS(StackTraceFrame, flags, kFlagsOffset)
-ACCESSORS(StackTraceFrame, abstract_code, AbstractCode, kAbstractCodeOffset)
-SMI_ACCESSORS(StackTraceFrame, offset, kOffsetOffset)
-ACCESSORS_CHECKED(StackTraceFrame, receiver, Object, kReceiverOffset,
-                  !IsWasmFrame())
-ACCESSORS_CHECKED(StackTraceFrame, function, JSFunction, kFunctionOffset,
-                  !IsWasmFrame())
-ACCESSORS_CHECKED(StackTraceFrame, wasm_object, Object, kWasmObjectOffset,
-                  IsWasmFrame())
-SMI_ACCESSORS_CHECKED(StackTraceFrame, wasm_function_index,
-                      kWasmFunctionIndexOffset, IsWasmFrame())
-
-bool StackTraceFrame::IsWasmFrame() const {
-  return ((flags() & kIsWasmFrame) != 0);
-}
-
-bool StackTraceFrame::IsJavaScriptFrame() const { return !IsWasmFrame(); }
-
-bool StackTraceFrame::IsStrict() const { return ((flags() & kIsStrict) != 0); }
-
-bool StackTraceFrame::ForceConstructor() const {
-  return ((flags() & kForceConstructor) != 0);
-}
 
 ACCESSORS(DebugInfo, shared, SharedFunctionInfo, kSharedFunctionInfoIndex)
 ACCESSORS(DebugInfo, debug_bytecode_array, Object, kDebugBytecodeArrayIndex)

src/objects-printer.cc

@@ -1274,21 +1274,6 @@ void Script::ScriptPrint(std::ostream& os) {  // NOLINT
   os << "\n";
 }
 
-void StackTraceFrame::StackTraceFramePrint(std::ostream& os) {  // NOLINT
-  HeapObject::PrintHeader(os, "StackTraceFrame");
-  os << "\n - flags: " << flags();
-  os << "\n - abstract_code: " << Brief(abstract_code());
-  os << "\n - offset: " << offset();
-  if (IsWasmFrame()) {
-    os << "\n - wasm_object: " << Brief(wasm_object());
-    os << "\n - wasm_function_index data: " << wasm_function_index();
-  } else {
-    DCHECK(IsJavaScriptFrame());
-    os << "\n - receiver: " << Brief(receiver());
-    os << "\n - function: " << Brief(function());
-  }
-  os << "\n";
-}
 
 void DebugInfo::DebugInfoPrint(std::ostream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "DebugInfo");

src/objects.h

@@ -389,7 +389,6 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;
   V(ALLOCATION_MEMENTO_TYPE)                                    \
   V(ALLOCATION_SITE_TYPE)                                       \
   V(SCRIPT_TYPE)                                                \
-  V(STACK_TRACE_FRAME_TYPE)                                     \
   V(TYPE_FEEDBACK_INFO_TYPE)                                    \
   V(ALIASED_ARGUMENTS_ENTRY_TYPE)                               \
   V(BOX_TYPE)                                                   \
@@ -505,7 +504,6 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;
   V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info)    \
   V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info)          \
   V(SCRIPT, Script, script)                                                  \
-  V(STACK_TRACE_FRAME, StackTraceFrame, stack_trace_frame)                   \
   V(ALLOCATION_SITE, AllocationSite, allocation_site)                        \
   V(ALLOCATION_MEMENTO, AllocationMemento, allocation_memento)               \
   V(TYPE_FEEDBACK_INFO, TypeFeedbackInfo, type_feedback_info)                \
@@ -677,7 +675,6 @@ enum InstanceType {
   ALLOCATION_SITE_TYPE,
   ALLOCATION_MEMENTO_TYPE,
   SCRIPT_TYPE,
-  STACK_TRACE_FRAME_TYPE,
   TYPE_FEEDBACK_INFO_TYPE,
   ALIASED_ARGUMENTS_ENTRY_TYPE,
   BOX_TYPE,
@@ -6507,6 +6504,7 @@ class Box : public Struct {
   DISALLOW_IMPLICIT_CONSTRUCTORS(Box);
 };
 
+
 // Container for metadata stored on each prototype map.
 class PrototypeInfo : public Struct {
  public:
@@ -6791,88 +6789,6 @@ class Script: public Struct {
   DISALLOW_IMPLICIT_CONSTRUCTORS(Script);
 };
 
-class StackTraceFrame : public Struct {
- public:
-  // --- Fields for JS and Wasm frames. ---
-
-  static const int kIsWasmFrame = 1 << 0;
-  static const int kForceConstructor = 1 << 1;
-  static const int kIsStrict = 1 << 2;
-
-  // [flags]
-  DECL_INT_ACCESSORS(flags)
-
-  // [abstract_code]
-  DECL_ACCESSORS(abstract_code, AbstractCode)
-
-  // [offset]
-  DECL_INT_ACCESSORS(offset)
-
-  // --- Fields for JS frames. ---
-
-  // [receiver]
-  DECL_ACCESSORS(receiver, Object)
-
-  // [function]
-  DECL_ACCESSORS(function, JSFunction)
-
-  // --- Fields for Wasm frames. ---
-
-  // [wasm_object]
-  DECL_ACCESSORS(wasm_object, Object)
-
-  // [wasm_function_index]
-  DECL_INT_ACCESSORS(wasm_function_index)
-
-  inline bool IsWasmFrame() const;
-  inline bool IsJavaScriptFrame() const;
-  inline bool IsStrict() const;
-  inline bool ForceConstructor() const;
-
-  Handle<Object> GetFileName();
-  Handle<Object> GetFunctionName();
-  Handle<Object> GetScriptNameOrSourceUrl();
-  Handle<Object> GetMethodName();
-  Handle<Object> GetTypeName();
-  Handle<Object> GetEvalOrigin();
-
-  int GetPosition();
-  // Return 1-based line number, including line offset.
-  int GetLineNumber();
-  // Return 1-based column number, including column offset if first line.
-  int GetColumnNumber();
-
-  bool IsNative();
-  bool IsToplevel();
-  bool IsEval();
-  bool IsConstructor();
-
-  Handle<String> ToString();
-
-  DECLARE_CAST(StackTraceFrame)
-
-  // Dispatched behavior.
-  DECLARE_PRINTER(StackTraceFrame)
-  DECLARE_VERIFIER(StackTraceFrame)
-
-  // Fields for all frame types.
-  static const int kFlagsOffset = HeapObject::kHeaderSize;
-  static const int kAbstractCodeOffset = kFlagsOffset + kPointerSize;
-  static const int kOffsetOffset = kAbstractCodeOffset + kPointerSize;
-
-  // Fields for JS frames.
-  static const int kReceiverOffset = kOffsetOffset + kPointerSize;
-  static const int kFunctionOffset = kReceiverOffset + kPointerSize;
-
-  // Fields for Wasm frames.
-  static const int kWasmObjectOffset = kOffsetOffset + kPointerSize;
-  static const int kWasmFunctionIndexOffset = kWasmObjectOffset + kPointerSize;
-
-  static const int kSize = kFunctionOffset + kPointerSize;
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(StackTraceFrame);
-};
 
 // List of builtin functions we want to identify to improve code
 // generation.

src/runtime/runtime-internal.cc

@@ -115,27 +115,22 @@ RUNTIME_FUNCTION(Runtime_ThrowWasmError) {
   // TODO(wasm): This implementation is temporary, see bug #5007:
   // https://bugs.chromium.org/p/v8/issues/detail?id=5007
   Handle<JSObject> error = Handle<JSObject>::cast(error_obj);
-
-  // Patch the stack trace (array of <receiver, function, code, position>).
-
   Handle<Object> stack_trace_obj = JSReceiver::GetDataProperty(
       error, isolate->factory()->stack_trace_symbol());
+  // Patch the stack trace (array of <receiver, function, code, position>).
   if (stack_trace_obj->IsJSArray()) {
     Handle<FixedArray> stack_elements(
         FixedArray::cast(JSArray::cast(*stack_trace_obj)->elements()));
-    Handle<StackTraceFrame> frame =
-        handle(StackTraceFrame::cast(stack_elements->get(0)));
-
-    DCHECK(frame->IsWasmFrame());
-    DCHECK(frame->offset() >= 0);
-    frame->set_offset(-1 - byte_offset);
+    DCHECK_EQ(1, stack_elements->length() % 4);
+    DCHECK(Code::cast(stack_elements->get(3))->kind() == Code::WASM_FUNCTION);
+    DCHECK(stack_elements->get(4)->IsSmi() &&
+           Smi::cast(stack_elements->get(4))->value() >= 0);
+    stack_elements->set(4, Smi::FromInt(-1 - byte_offset));
   }
-
-  // Patch the detailed stack trace (array of JSObjects with various
-  // properties).
-
   Handle<Object> detailed_stack_trace_obj = JSReceiver::GetDataProperty(
       error, isolate->factory()->detailed_stack_trace_symbol());
+  // Patch the detailed stack trace (array of JSObjects with various
+  // properties).
   if (detailed_stack_trace_obj->IsJSArray()) {
     Handle<FixedArray> stack_elements(
         FixedArray::cast(JSArray::cast(*detailed_stack_trace_obj)->elements()));

src/types.cc

@@ -248,7 +248,6 @@ Type::bitset BitsetType::Lub(i::Map* map) {
     case TRANSITION_ARRAY_TYPE:
     case FOREIGN_TYPE:
     case SCRIPT_TYPE:
-    case STACK_TRACE_FRAME_TYPE:
     case CODE_TYPE:
     case PROPERTY_CELL_TYPE:
       return kOtherInternal & kTaggedPointer;