Fast-codegen: Implementing try/finally on top of nesting context.

src/x64/macro-assembler-x64.cc

 // Copyright 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 1422 matching lines @@
   // Save the current handler.
   movq(kScratchRegister, ExternalReference(Top::k_handler_address));
   push(Operand(kScratchRegister, 0));
   // Link this handler.
   movq(Operand(kScratchRegister, 0), rsp);
 }
 
 
 void MacroAssembler::PopTryHandler() {
   ASSERT_EQ(0, StackHandlerConstants::kNextOffset);
+  // Unlink this handler.
   movq(kScratchRegister, ExternalReference(Top::k_handler_address));
   pop(Operand(kScratchRegister, 0));
+  // Remove the remaining fields.
   addq(rsp, Immediate(StackHandlerConstants::kSize - kPointerSize));
 }
 
 
 void MacroAssembler::Ret() {
   ret(0);
 }
 
 
 void MacroAssembler::FCmp() {
@@ skipping 943 matching lines @@
 CodePatcher::~CodePatcher() {
   // Indicate that code has changed.
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 } }  // namespace v8::internal