Simplify the IA32 exception handler block by removing the unused code...

src/ia32/codegen-ia32.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6917 matching lines @@
   __ Set(eax, Immediate(argc_));
   __ Set(ebx, Immediate(0));
   __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION);
   Handle<Code> adaptor(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
   __ jmp(adaptor, RelocInfo::CODE_TARGET);
 }
 
 
 
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
-  ASSERT(StackHandlerConstants::kSize == 6 * kPointerSize);  // adjust this code
+  // Adjust this code if not the case.
+  ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
   ExternalReference handler_address(Top::k_handler_address);
   __ mov(edx, Operand::StaticVariable(handler_address));
-  __ mov(ecx, Operand(edx, -1 * kPointerSize));  // get next in chain
+  // Get next in chain.
+  __ mov(ecx, Operand(edx, StackHandlerConstants::kAddressDisplacement));
   __ mov(Operand::StaticVariable(handler_address), ecx);
   __ mov(esp, Operand(edx));
-  __ pop(edi);
   __ pop(ebp);
-  __ pop(edx);  // remove code pointer
-  __ pop(edx);  // remove state
+  __ pop(edx);  // Remove state.
 
   // Before returning we restore the context from the frame pointer if not NULL.
   // The frame pointer is NULL in the exception handler of a JS entry frame.
   __ xor_(esi, Operand(esi));  // tentatively set context pointer to NULL
   Label skip;
   __ cmp(ebp, 0);
   __ j(equal, &skip, not_taken);
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
   __ bind(&skip);
 
@@ skipping 75 matching lines @@
 
   // Handle normal exception.
   __ jmp(throw_normal_exception);
 
   // Retry.
   __ bind(&retry);
 }
 
 
 void CEntryStub::GenerateThrowOutOfMemory(MacroAssembler* masm) {
+  // Adjust this code if not the case.
+  ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+
   // Fetch top stack handler.
   ExternalReference handler_address(Top::k_handler_address);
   __ mov(edx, Operand::StaticVariable(handler_address));
 
   // Unwind the handlers until the ENTRY handler is found.
   Label loop, done;
   __ bind(&loop);
   // Load the type of the current stack handler.
   const int kStateOffset = StackHandlerConstants::kAddressDisplacement +
       StackHandlerConstants::kStateOffset;
@@ skipping 20 matching lines @@
   ExternalReference pending_exception(Top::k_pending_exception_address);
   __ mov(Operand::StaticVariable(pending_exception), eax);
 
   // Restore the stack to the address of the ENTRY handler
   __ mov(esp, Operand(edx));
 
   // Clear the context pointer;
   __ xor_(esi, Operand(esi));
 
   // Restore registers from handler.
-  __ pop(edi);  // PP
   __ pop(ebp);  // FP
-  __ pop(edx);  // Code
   __ pop(edx);  // State
 
   __ ret(0);
 }
 
 
 void CEntryStub::GenerateBody(MacroAssembler* masm, bool is_debug_break) {
   // eax: number of arguments including receiver
   // ebx: pointer to C function  (C callee-saved)
   // ebp: frame pointer  (restored after C call)
@@ skipping 215 matching lines @@
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal