Refactored EXTERNAL_REFERENCE handling.

Previously, the result of target_reference_address() could only be
read, writing to it would have had an architecture-dependent effect,
e.g. writing into the code on ia32, a no-op on arm, etc.

This refactoring-only CL turns this into a simple getter, making it
impossible to use incorrectly.

More to come...

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/46583006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17467 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm-inl.h

@@ -160,10 +160,9 @@ void RelocInfo::set_target_object(Object* target, WriteBarrierMode mode) {
 }
 
 
-Address* RelocInfo::target_reference_address() {
+Address RelocInfo::target_reference() {
   ASSERT(rmode_ == EXTERNAL_REFERENCE);
-  reconstructed_adr_ptr_ = Assembler::target_address_at(pc_);
-  return &reconstructed_adr_ptr_;
+  return Assembler::target_address_at(pc_);
 }
 
 

src/assembler.cc

@@ -819,8 +819,8 @@ void RelocInfo::Print(Isolate* isolate, FILE* out) {
   } else if (rmode_ == EXTERNAL_REFERENCE) {
     ExternalReferenceEncoder ref_encoder(isolate);
     PrintF(out, " (%s)  (%p)",
-           ref_encoder.NameOfAddress(*target_reference_address()),
-           *target_reference_address());
+           ref_encoder.NameOfAddress(target_reference()),
+           target_reference());
   } else if (IsCodeTarget(rmode_)) {
     Code* code = Code::GetCodeFromTargetAddress(target_address());
     PrintF(out, " (%s)  (%p)", Code::Kind2String(code->kind()),

src/assembler.h

@@ -425,7 +425,7 @@ class RelocInfo BASE_EMBEDDED {
 
   // Read/modify the reference in the instruction this relocation
   // applies to; can only be called if rmode_ is external_reference
-  INLINE(Address* target_reference_address());
+  INLINE(Address target_reference());
 
   // Read/modify the address of a call instruction. This is used to relocate
   // the break points where straight-line code is patched with a call

src/disassembler.cc

@@ -227,7 +227,7 @@ static int DecodeIt(Isolate* isolate,
         out.AddFormatted("    ;; object: %s", *obj_name);
       } else if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
         const char* reference_name =
-            ref_encoder.NameOfAddress(*relocinfo.target_reference_address());
+            ref_encoder.NameOfAddress(relocinfo.target_reference());
         out.AddFormatted("    ;; external reference (%s)", reference_name);
       } else if (RelocInfo::IsCodeTarget(rmode)) {
         out.AddFormatted("    ;; code:");

src/ia32/assembler-ia32-inl.h

@@ -145,9 +145,9 @@ void RelocInfo::set_target_object(Object* target, WriteBarrierMode mode) {
 }
 
 
-Address* RelocInfo::target_reference_address() {
+Address RelocInfo::target_reference() {
   ASSERT(rmode_ == RelocInfo::EXTERNAL_REFERENCE);
-  return reinterpret_cast<Address*>(pc_);
+  return Memory::Address_at(pc_);
 }
 
 

src/mips/assembler-mips-inl.h

@@ -213,10 +213,9 @@ void RelocInfo::set_target_object(Object* target, WriteBarrierMode mode) {
 }
 
 
-Address* RelocInfo::target_reference_address() {
+Address RelocInfo::target_reference() {
   ASSERT(rmode_ == EXTERNAL_REFERENCE);
-  reconstructed_adr_ptr_ = Assembler::target_address_at(pc_);
-  return &reconstructed_adr_ptr_;
+  return Assembler::target_address_at(pc_);
 }
 
 

src/objects.cc

@@ -10322,8 +10322,8 @@ void ObjectVisitor::VisitEmbeddedPointer(RelocInfo* rinfo) {
 
 
 void ObjectVisitor::VisitExternalReference(RelocInfo* rinfo) {
-  Address* p = rinfo->target_reference_address();
-  VisitExternalReference(p);
+  Address p = rinfo->target_reference();
+  VisitExternalReference(&p);
 }
 
 

src/serialize.cc

@@ -1694,12 +1694,12 @@ void Serializer::ObjectSerializer::VisitExternalReference(RelocInfo* rinfo) {
   Address references_start = rinfo->target_address_address();
   int skip = OutputRawData(references_start, kCanReturnSkipInsteadOfSkipping);
 
-  Address* current = rinfo->target_reference_address();
+  Address current = rinfo->target_reference();
   int representation = rinfo->IsCodedSpecially() ?
                        kFromCode + kStartOfObject : kPlain + kStartOfObject;
   sink_->Put(kExternalReference + representation, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
-  int reference_id = serializer_->EncodeExternalReference(*current);
+  int reference_id = serializer_->EncodeExternalReference(current);
   sink_->PutInt(reference_id, "reference id");
   bytes_processed_so_far_ += rinfo->target_address_size();
 }

src/x64/assembler-x64-inl.h

@@ -309,9 +309,9 @@ Object** RelocInfo::target_object_address() {
 }
 
 
-Address* RelocInfo::target_reference_address() {
+Address RelocInfo::target_reference() {
   ASSERT(rmode_ == RelocInfo::EXTERNAL_REFERENCE);
-  return reinterpret_cast<Address*>(pc_);
+  return Memory::Address_at(pc_);
 }