[liveedit] reimplement frame restarting.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 4063 matching lines @@
   if (FLAG_native_code_counters && counter->Enabled()) {
     Operand counter_operand = ExternalOperand(ExternalReference(counter));
     if (value == 1) {
       decl(counter_operand);
     } else {
       subl(counter_operand, Immediate(value));
     }
   }
 }
 
-
 void MacroAssembler::DebugBreak() {
   Set(rax, 0);  // No arguments.
   LoadAddress(rbx,
               ExternalReference(Runtime::kHandleDebuggerStatement, isolate()));
   CEntryStub ces(isolate(), 1);
   DCHECK(AllowThisStubCall(&ces));
   Call(ces.GetCode(), RelocInfo::DEBUGGER_STATEMENT);
 }
 
+void MacroAssembler::MaybeDropFrames() {
+  // Check whether we need to drop frames to restart a function on the stack.
+  ExternalReference new_fp = ExternalReference::debug_new_fp_address(isolate());
+  Load(rbx, new_fp);
+  testp(rbx, rbx);
+  j(not_zero, isolate()->builtins()->FrameDropperTrampoline(),
+    RelocInfo::CODE_TARGET);
+}
+
 void MacroAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
                                         Register caller_args_count_reg,
                                         Register scratch0, Register scratch1,
                                         ReturnAddressState ra_state) {
 #if DEBUG
   if (callee_args_count.is_reg()) {
     DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
                        scratch1));
   } else {
     DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
@@ skipping 179 matching lines @@
       j(equal, &invoke, Label::kNear);
       DCHECK(expected.reg().is(rbx));
     } else if (!expected.reg().is(actual.reg())) {
       // Both expected and actual are in (different) registers. This
       // is the case when we invoke functions using call and apply.
       cmpp(expected.reg(), actual.reg());
       j(equal, &invoke, Label::kNear);
       DCHECK(actual.reg().is(rax));
       DCHECK(expected.reg().is(rbx));
     } else {
+      definitely_matches = true;
       Move(rax, actual.reg());
     }
   }
 
   if (!definitely_matches) {
     Handle<Code> adaptor = isolate()->builtins()->ArgumentsAdaptorTrampoline();
     if (flag == CALL_FUNCTION) {
       call_wrapper.BeforeCall(CallSize(adaptor));
       Call(adaptor, RelocInfo::CODE_TARGET);
       call_wrapper.AfterCall();
@@ skipping 992 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64