[interpreter] Make setting of function data more resilient.

src/objects-inl.h

 // Copyright 2012 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5799 matching lines @@
 bool SharedFunctionInfo::IsApiFunction() {
   return function_data()->IsFunctionTemplateInfo();
 }
 
 
 FunctionTemplateInfo* SharedFunctionInfo::get_api_func_data() {
   DCHECK(IsApiFunction());
   return FunctionTemplateInfo::cast(function_data());
 }
 
+void SharedFunctionInfo::set_api_func_data(FunctionTemplateInfo* data) {
+  DCHECK(function_data()->IsUndefined());
+  set_function_data(data);
+}
 
 bool SharedFunctionInfo::HasBuiltinFunctionId() {
   return function_data()->IsSmi();
 }
 
 
 BuiltinFunctionId SharedFunctionInfo::builtin_function_id() {
   DCHECK(HasBuiltinFunctionId());
   return static_cast<BuiltinFunctionId>(Smi::cast(function_data())->value());
 }
 
+void SharedFunctionInfo::set_builtin_function_id(BuiltinFunctionId id) {
+  DCHECK(function_data()->IsUndefined() || HasBuiltinFunctionId());
+  set_function_data(Smi::FromInt(id));
+}
 
 bool SharedFunctionInfo::HasBytecodeArray() {
   return function_data()->IsBytecodeArray();
 }
 
 
 BytecodeArray* SharedFunctionInfo::bytecode_array() {
   DCHECK(HasBytecodeArray());
   return BytecodeArray::cast(function_data());
 }
 
+void SharedFunctionInfo::set_bytecode_array(BytecodeArray* bytecode) {
+  DCHECK(function_data()->IsUndefined());

[Michael Starzinger, 2016/02/25 14:43:43]

This would now imply the DCHECKs in compiler.cc about only compiling once.
However I am inclined to leave the explicit DCHECKs in compiler.cc as
"documentation". Please let me know if you disagree.

[rmcilroy, 2016/02/25 15:33:55]

SGTM

+  set_function_data(bytecode);
+}
+
+void SharedFunctionInfo::ClearBytecodeArray() {
+  DCHECK(function_data()->IsUndefined() || HasBytecodeArray());
+  set_function_data(GetHeap()->undefined_value());
+}
 
 int SharedFunctionInfo::ic_age() {
   return ICAgeBits::decode(counters());
 }
 
 
 void SharedFunctionInfo::set_ic_age(int ic_age) {
   set_counters(ICAgeBits::update(counters(), ic_age));
 }
 
@@ skipping 1830 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_