[wasm] Fix location for error in asm.js ToNumber conversion

src/frames.cc

Index: src/frames.cc
diff --git a/src/frames.cc b/src/frames.cc
index f3cda57652c3e5c8d68d36ae05a1da0a5abdaf52..64ed6dc04be016359e19a41755bb42eec2dc1f6e 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -1536,11 +1536,18 @@ int WasmFrame::position() const {
         isolate());
     DCHECK_LE(0, position);
     position = WasmCompiledModule::GetAsmJsSourcePosition(
-        compiled_module, function_index(), static_cast<uint32_t>(position));
+        compiled_module, function_index(), static_cast<uint32_t>(position),
+        at_to_number_conversion());
   }
   return position;
 }
 
+bool WasmFrame::at_to_number_conversion() const {
+  // WasmToJsFrame::ComputeCallerState encoded this for us in the constant pool
+  // address ;)
+  return !!constant_pool_address();
+}
+
 int WasmFrame::LookupExceptionHandlerInTable(int* stack_slots) {
   DCHECK_NOT_NULL(stack_slots);
   Code* code = LookupCode();
@@ -1550,6 +1557,21 @@ int WasmFrame::LookupExceptionHandlerInTable(int* stack_slots) {
   return table->LookupReturn(pc_offset);
 }
 
+void WasmToJsFrame::ComputeCallerState(State* state) const {
+  // Remember at which of the two calls inside it we are, and transfer this
+  // information to the subsequent WASM frame.
+  Code* code = unchecked_code();
+  AbstractCode* abstract_code = AbstractCode::cast(code);
+  int offset = static_cast<int>(pc() - code->instruction_start());
+  int at_to_number_call = abstract_code->SourcePosition(offset);
+  DCHECK(at_to_number_call == 0 || at_to_number_call == 1);
+  StubFrame::ComputeCallerState(state);
+  DCHECK_EQ(StackFrame::WASM, ComputeType(iterator_, state));
+  // Use a little hack here: The constant pool address is not used for wasm
+  // frames, so use it to encode whether we are at the to_number call.
+  state->constant_pool_address = reinterpret_cast<Address*>(at_to_number_call);
+}
+
 namespace {