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

runtime/vm/disassembler.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/disassembler.h"
 
 #include "vm/assembler.h"
 #include "vm/deopt_instructions.h"
 #include "vm/globals.h"
 #include "vm/il_printer.h"
 #include "vm/instructions.h"
 #include "vm/json_stream.h"
 #include "vm/log.h"
 #include "vm/os.h"
 #include "vm/code_patcher.h"
 
 
 namespace dart {
 
 #ifndef PRODUCT
 
 DECLARE_FLAG(bool, trace_inlining_intervals);
 
 void DisassembleToStdout::ConsumeInstruction(const Code& code,
                                              char* hex_buffer,
                                              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);
   THR_Print("%p    %s", pc_ptr, hex_buffer);
   int hex_length = strlen(hex_buffer);
   if (hex_length < kHexColumnWidth) {
     for (int i = kHexColumnWidth - hex_length; i > 0; i--) {
       THR_Print(" ");
     }
   }
   THR_Print("%s", human_buffer);
+  if (object != NULL) {
+    THR_Print("   %s", object->ToCString());
+  }
   THR_Print("\n");
 }
 
 
 void DisassembleToStdout::Print(const char* format, ...) {
   va_list args;
   va_start(args, format);
   THR_VPrint(format, args);
   va_end(args);
 }
 
 
 void DisassembleToJSONStream::ConsumeInstruction(const Code& code,
                                                  char* hex_buffer,
                                                  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,
   // of the code, and the third is a human readable string, and the fourth is
   // the object loaded by the instruction.
   jsarr_.AddValueF("%" Pp "", pc);
   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.
   }
 }
 
 
 void DisassembleToJSONStream::Print(const char* format, ...) {
   va_list args;
   va_start(args, format);
   intptr_t len = OS::VSNPrint(NULL, 0, format, args);
@@ skipping 11 matching lines @@
   // Instructions are represented as four consecutive values in a JSON array.
   // Comments only use the third slot. See above comment for more information.
   jsarr_.AddValueNull();
   jsarr_.AddValueNull();
   jsarr_.AddValue(p);
   jsarr_.AddValueNull();
   free(p);
 }
 
 
-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,
                                const Code& code) {
   const Code::Comments& comments =
       code.IsNull() ? Code::Comments::New(0) : code.comments();
   ASSERT(formatter != NULL);
   char hex_buffer[kHexadecimalBufferSize];  // Instruction in hexadecimal form.
   char human_buffer[kUserReadableBufferSize];  // Human-readable instruction.
   uword pc = start;
@@ skipping 24 matching lines @@
         } else {
           f.Print(" -> %s", name);
         }
       }
       if (!first) {
         f.Print("]\n");
         formatter->Print(str);
       }
     }
     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;
   }
 }
 
 
 void Disassembler::DisassembleCodeHelper(
     const char* function_fullname, const Code& code, bool optimized) {
   THR_Print("Code for %sfunction '%s' {\n",
             optimized ? "optimized " : "",
@@ skipping 150 matching lines @@
     const Function& function, bool optimized) {
   const char* function_fullname = function.ToFullyQualifiedCString();
   const Code& code = Code::Handle(function.unoptimized_code());
   DisassembleCodeHelper(function_fullname, code, optimized);
 }
 
 
 #endif  // !PRODUCT
 
 }  // namespace dart