[liveedit] reimplement frame restarting.

src/arm/macro-assembler-arm.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.
 
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 1912 matching lines @@
 
 void MacroAssembler::DebugBreak() {
   mov(r0, Operand::Zero());
   mov(r1,
       Operand(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 restart_fp =
+      ExternalReference::debug_restart_fp_address(isolate());
+  mov(r1, Operand(restart_fp));
+  ldr(r1, MemOperand(r1));
+  tst(r1, r1);
+  Jump(isolate()->builtins()->FrameDropperTrampoline(), RelocInfo::CODE_TARGET,
+       ne);
+}
 
 void MacroAssembler::PushStackHandler() {
   // Adjust this code if not the case.
   STATIC_ASSERT(StackHandlerConstants::kSize == 1 * kPointerSize);
   STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
 
   // Link the current handler as the next handler.
   mov(r6, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
   ldr(r5, MemOperand(r6));
   push(r5);
@@ skipping 1925 matching lines @@
     }
   }
   if (mag.shift > 0) mov(result, Operand(result, ASR, mag.shift));
   add(result, result, Operand(dividend, LSR, 31));
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM