[wasm] Fix race in code lookup for exception locations.

R=clemensh@chromium.org
BUG=v8:7424

Change-Id: Ifa7029872c4d5cfda2f2411534abad6970dda323
Reviewed-on: https://chromium-review.googlesource.com/1156549Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55034}

src/isolate.cc

@@ -1737,18 +1737,15 @@ bool Isolate::ComputeLocationFromStackTrace(MessageLocation* target,
       Handle<WasmInstanceObject> instance(elements->WasmInstance(i), this);
       uint32_t func_index =
           static_cast<uint32_t>(elements->WasmFunctionIndex(i)->value());
+      wasm::WasmCode* wasm_code = reinterpret_cast<wasm::WasmCode*>(
+          elements->WasmCodeObject(i)->foreign_address());
       int code_offset = elements->Offset(i)->value();
-
-      // TODO(titzer): store a reference to the code object in FrameArray;
-      // a second lookup here could lead to inconsistency.
-      int byte_offset =
-          FrameSummary::WasmCompiledFrameSummary::GetWasmSourcePosition(
-              instance->module_object()->native_module()->code(func_index),
-              code_offset);
-
       bool is_at_number_conversion =
           elements->IsAsmJsWasmFrame(i) &&
           elements->Flags(i)->value() & FrameArray::kAsmJsAtNumberConversion;
+      int byte_offset =
+          FrameSummary::WasmCompiledFrameSummary::GetWasmSourcePosition(
+              wasm_code, code_offset);
       int pos = WasmModuleObject::GetSourcePosition(
           handle(instance->module_object(), this), func_index, byte_offset,
           is_at_number_conversion);

src/messages.cc

@@ -649,8 +649,8 @@ void WasmStackFrame::FromFrameArray(Isolate* isolate, Handle<FrameArray> array,
   if (array->IsWasmInterpretedFrame(frame_ix)) {
     code_ = nullptr;
   } else {
-    code_ = wasm_instance_->module_object()->native_module()->code(
-        wasm_func_index_);
+    code_ = reinterpret_cast<wasm::WasmCode*>(
+        array->WasmCodeObject(frame_ix)->foreign_address());
   }
   offset_ = array->Offset(frame_ix)->value();
 }

src/objects.cc

@@ -10629,14 +10629,16 @@ Handle<FrameArray> FrameArray::AppendJSFrame(Handle<FrameArray> in,
 Handle<FrameArray> FrameArray::AppendWasmFrame(
     Handle<FrameArray> in, Handle<WasmInstanceObject> wasm_instance,
     int wasm_function_index, wasm::WasmCode* code, int offset, int flags) {
+  Isolate* isolate = wasm_instance->GetIsolate();
   const int frame_count = in->FrameCount();
   const int new_length = LengthFor(frame_count + 1);
-  Handle<FrameArray> array =
-      EnsureSpace(wasm_instance->GetIsolate(), in, new_length);
+  Handle<FrameArray> array = EnsureSpace(isolate, in, new_length);
+  // The {code} will be {nullptr} for interpreted wasm frames.
+  Handle<Foreign> code_foreign =
+      isolate->factory()->NewForeign(reinterpret_cast<Address>(code));
   array->SetWasmInstance(frame_count, *wasm_instance);
   array->SetWasmFunctionIndex(frame_count, Smi::FromInt(wasm_function_index));
-  // The {code} will be {nullptr} for interpreted wasm frames.
-  array->SetIsWasmInterpreterFrame(frame_count, Smi::FromInt(code == nullptr));
+  array->SetWasmCodeObject(frame_count, *code_foreign);
   array->SetOffset(frame_count, Smi::FromInt(offset));
   array->SetFlags(frame_count, Smi::FromInt(flags));
   array->set(kFrameCountIndex, Smi::FromInt(frame_count + 1));

src/objects/frame-array.h

@@ -20,7 +20,7 @@ class Handle;
 #define FRAME_ARRAY_FIELD_LIST(V)     \
   V(WasmInstance, WasmInstanceObject) \
   V(WasmFunctionIndex, Smi)           \
-  V(IsWasmInterpreterFrame, Smi)      \
+  V(WasmCodeObject, Foreign)          \
   V(Receiver, Object)                 \
   V(Function, JSFunction)             \
   V(Code, AbstractCode)               \
@@ -74,7 +74,7 @@ class FrameArray : public FixedArray {
 
   static const int kWasmInstanceOffset = 0;
   static const int kWasmFunctionIndexOffset = 1;
-  static const int kIsWasmInterpreterFrameOffset = 2;
+  static const int kWasmCodeObjectOffset = 2;
 
   static const int kReceiverOffset = 0;
   static const int kFunctionOffset = 1;