[interpreter, debugger] support debug breaks via bytecode array copy

src/interpreter/interpreter-assembler.cc

 // Copyright 2015 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 "src/interpreter/interpreter-assembler.h"
 
 #include <ostream>
 
 #include "src/code-factory.h"
 #include "src/frames.h"
@@ skipping 407 matching lines @@
       Load(MachineType::Pointer(), DispatchTableRawPointer(),
            Word32Shl(target_bytecode, Int32Constant(kPointerSizeLog2)));
 
   InterpreterDispatchDescriptor descriptor(isolate());
   Node* args[] = {GetAccumulator(),          RegisterFileRawPointer(),
                   new_bytecode_offset,       BytecodeArrayTaggedPointer(),
                   DispatchTableRawPointer(), GetContext()};
   TailCall(descriptor, target_code_object, args, 0);
 }
 
+void InterpreterAssembler::DispatchToHandler(Node* handler) {
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
+
+  InterpreterDispatchDescriptor descriptor(isolate());
+  Node* args[] = {GetAccumulator(),          RegisterFileRawPointer(),
+                  BytecodeOffset(),          BytecodeArrayTaggedPointer(),
+                  DispatchTableRawPointer(), GetContext()};
+  TailCall(descriptor, handler, args, 0);
+}
+
 void InterpreterAssembler::InterpreterReturn() {
   if (FLAG_trace_ignition) {
     TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
   }
   InterpreterDispatchDescriptor descriptor(isolate());
   Node* exit_trampoline_code_object =
       HeapConstant(isolate()->builtins()->InterpreterExitTrampoline());
   Node* args[] = {GetAccumulator(),          RegisterFileRawPointer(),
                   BytecodeOffset(),          BytecodeArrayTaggedPointer(),
                   DispatchTableRawPointer(), GetContext()};
   TailCall(descriptor, exit_trampoline_code_object, args, 0);

[rmcilroy, 2016/02/16 10:46:38]

Could you make InterpreterReturn (and possibly use DispatchTo if you add
new_bytecode_offset as an argument) call DispatchToHandler().

[Yang, 2016/02/19 13:09:18]

Done.

 }
 
 void InterpreterAssembler::StackCheck() {
   CodeStubAssembler::Label end(this);
   CodeStubAssembler::Label ok(this);
   CodeStubAssembler::Label stack_guard(this);
 
   Node* sp = LoadStackPointer();
   Node* stack_limit = Load(
       MachineType::Pointer(),
@@ skipping 43 matching lines @@
 #elif V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_X87
   return true;
 #else
 #error "Unknown Architecture"
 #endif
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8