Use the Code's pointer offsets to find object references when disassembling IA32.

runtime/vm/disassembler.cc

Index: runtime/vm/disassembler.cc
diff --git a/runtime/vm/disassembler.cc b/runtime/vm/disassembler.cc
index d1ff765dfe1a76c726cc981367ef4f318dd60b30..a735289c94cd9b83e89607469f9bce426cd6e805 100644
--- a/runtime/vm/disassembler.cc
+++ b/runtime/vm/disassembler.cc
@@ -26,6 +26,7 @@ void DisassembleToStdout::ConsumeInstruction(const Code& code,
                                              intptr_t hex_size,
                                              char* human_buffer,
                                              intptr_t human_size,
+                                             Object* object,
                                              uword pc) {
   static const int kHexColumnWidth = 23;
   uint8_t* pc_ptr = reinterpret_cast<uint8_t*>(pc);
@@ -37,6 +38,9 @@ void DisassembleToStdout::ConsumeInstruction(const Code& code,
     }
   }
   THR_Print("%s", human_buffer);
+  if (object != NULL) {
+    THR_Print("   %s", object->ToCString());
+  }
   THR_Print("\n");
 }
 
@@ -54,6 +58,7 @@ void DisassembleToJSONStream::ConsumeInstruction(const Code& code,
                                                  intptr_t hex_size,
                                                  char* human_buffer,
                                                  intptr_t human_size,
+                                                 Object* object,
                                                  uword pc) {
   // Instructions are represented as four consecutive values in a JSON array.
   // The first is the address of the instruction, the second is the hex string,
@@ -63,9 +68,8 @@ void DisassembleToJSONStream::ConsumeInstruction(const Code& code,
   jsarr_.AddValue(hex_buffer);
   jsarr_.AddValue(human_buffer);
 
-  Object& object = Object::Handle();
-  if (DecodeLoadObjectFromPoolOrThread(pc, code, &object)) {
-    jsarr_.AddValue(object);
+  if (object != NULL) {
+    jsarr_.AddValue(*object);
   } else {
     jsarr_.AddValueNull();  // Not a reference to null.
   }
@@ -97,33 +101,6 @@ void DisassembleToJSONStream::Print(const char* format, ...) {
 }
 
 
-class FindAddrVisitor : public FindObjectVisitor {
- public:
-  explicit FindAddrVisitor(uword addr) : addr_(addr) { }
-  virtual ~FindAddrVisitor() { }
-
-  virtual uword filter_addr() const { return addr_; }
-
-  // Check if object matches find condition.
-  virtual bool FindObject(RawObject* obj) const {
-    return obj == reinterpret_cast<RawObject*>(addr_);
-  }
-
- private:
-  const uword addr_;
-
-  DISALLOW_COPY_AND_ASSIGN(FindAddrVisitor);
-};
-
-
-bool Disassembler::CanFindOldObject(uword addr) {
-  FindAddrVisitor visitor(addr);
-  NoSafepointScope no_safepoint;
-  return Dart::vm_isolate()->heap()->FindOldObject(&visitor) != Object::null()
-      || Isolate::Current()->heap()->FindOldObject(&visitor) != Object::null();
-}
-
-
 void Disassembler::Disassemble(uword start,
                                uword end,
                                DisassemblyFormatter* formatter,
@@ -168,16 +145,18 @@ void Disassembler::Disassemble(uword start,
       }
     }
     int instruction_length;
+    Object* object;
     DecodeInstruction(hex_buffer,
                       sizeof(hex_buffer),
                       human_buffer,
                       sizeof(human_buffer),
-                      &instruction_length, pc);
+                      &instruction_length, code, &object, pc);
     formatter->ConsumeInstruction(code,
                                   hex_buffer,
                                   sizeof(hex_buffer),
                                   human_buffer,
                                   sizeof(human_buffer),
+                                  object,
                                   pc);
     pc += instruction_length;
   }