Cleaned up some debugger stuff on ia32 and x64

src/ia32/debug-ia32.cc

Index: src/ia32/debug-ia32.cc
===================================================================
--- src/ia32/debug-ia32.cc	(revision 2860)
+++ src/ia32/debug-ia32.cc	(working copy)
@@ -36,9 +36,7 @@
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 
-// A debug break in the frame exit code is identified by a call instruction.
 bool BreakLocationIterator::IsDebugBreakAtReturn() {
-  // Opcode E8 is call.
   return Debug::IsDebugBreakAtReturn(rinfo());
 }
 
@@ -49,7 +47,7 @@
 void BreakLocationIterator::SetDebugBreakAtReturn() {
   ASSERT(Debug::kIa32JSReturnSequenceLength >=
          Debug::kIa32CallInstructionLength);
-  rinfo()->PatchCodeWithCall(Debug::debug_break_return_entry()->entry(),
+  rinfo()->PatchCodeWithCall(Debug::debug_break_return()->entry(),
       Debug::kIa32JSReturnSequenceLength - Debug::kIa32CallInstructionLength);
 }
 
@@ -61,11 +59,11 @@
 }
 
 
-// Check whether the JS frame exit code has been patched with a debug break.
+// A debug break in the frame exit code is identified by the JS frame exit code
+// having been patched with a call instruction.
 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
   ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
-  // Opcode E8 is call.
-  return (*(rinfo->pc()) == 0xE8);
+  return rinfo->IsCallInstruction();
 }
 
 
@@ -194,17 +192,6 @@
 }
 
 
-void Debug::GenerateReturnDebugBreakEntry(MacroAssembler* masm) {
-  // OK to clobber ebx as we are returning from a JS function through the code
-  // generated by CodeGenerator::GenerateReturnSequence()
-  ExternalReference debug_break_return =
-      ExternalReference(Debug_Address::DebugBreakReturn());
-  __ mov(ebx, Operand::StaticVariable(debug_break_return));
-  __ add(Operand(ebx), Immediate(Code::kHeaderSize - kHeapObjectTag));
-  __ jmp(Operand(ebx));
-}
-
-
 void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
   // Register state for stub CallFunction (from CallFunctionStub in ic-ia32.cc).
   // ----------- S t a t e -------------