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

src/interpreter/bytecodes.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/bytecodes.h"
 
 #include "src/frames.h"
 #include "src/interpreter/bytecode-traits.h"
 
 namespace v8 {
@@ skipping 53 matching lines @@
 
 // static
 Bytecode Bytecodes::FromByte(uint8_t value) {
   Bytecode bytecode = static_cast<Bytecode>(value);
   DCHECK(bytecode <= Bytecode::kLast);
   return bytecode;
 }
 
 
 // static
+Bytecode Bytecodes::GetDebugBreak(Bytecode bytecode) {
+  switch (Size(bytecode)) {
+#define CASE(Name, ...)                                  \
+  case BytecodeTraits<__VA_ARGS__, OPERAND_TERM>::kSize: \
+    return Bytecode::k##Name;
+    DEBUG_BREAK_BYTECODE_LIST(CASE)
+#undef CASE
+    default:
+      break;
+  }
+  return Bytecode::kLdaUndefined;

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

UNREACHABLE() and return static_cast<Bytecode>(-1);

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

Done.

+}
+
+// static
 int Bytecodes::Size(Bytecode bytecode) {
   DCHECK(bytecode <= Bytecode::kLast);
   switch (bytecode) {
 #define CASE(Name, ...)   \
   case Bytecode::k##Name: \
     return BytecodeTraits<__VA_ARGS__, OPERAND_TERM>::kSize;
     BYTECODE_LIST(CASE)
 #undef CASE
   }
   UNREACHABLE();
@@ skipping 176 matching lines @@
 }
 
 
 // static
 bool Bytecodes::IsCallOrNew(Bytecode bytecode) {
   return bytecode == Bytecode::kCall || bytecode == Bytecode::kNew ||
          bytecode == Bytecode::kCallWide || bytecode == Bytecode::kNewWide;
 }
 
 // static
+bool Bytecodes::IsDebugBreak(Bytecode bytecode) {
+#define DEBUG_BREAK(Name, ...) \
+  if (bytecode == Bytecode::k##Name) return true;

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

Could you do this as a switch statement instead please

[Yang, 2016/02/19 13:09:17]

Done.

+  DEBUG_BREAK_BYTECODE_LIST(DEBUG_BREAK);
+#undef DEBUG_BREAK
+  return false;
+}
+
+// static
 bool Bytecodes::IsJumpOrReturn(Bytecode bytecode) {
   return bytecode == Bytecode::kReturn || IsJump(bytecode);
 }
 
 // static
 bool Bytecodes::IsIndexOperandType(OperandType operand_type) {
   return operand_type == OperandType::kIdx8 ||
          operand_type == OperandType::kIdx16;
 }
 
@@ skipping 96 matching lines @@
     SNPrintF(buf, "%02x ", bytecode_start[i]);
     os << buf.start();
   }
   const int kBytecodeColumnSize = 6;
   for (int i = bytecode_size; i < kBytecodeColumnSize; i++) {
     os << "   ";
   }
 
   os << bytecode << " ";
 
+  // Operands for the debug break are from the original instruction.
+  if (IsDebugBreak(bytecode)) return os;
+
   int number_of_operands = NumberOfOperands(bytecode);
   int range = 0;
   for (int i = 0; i < number_of_operands; i++) {
     OperandType op_type = GetOperandType(bytecode, i);
     const uint8_t* operand_start =
         &bytecode_start[GetOperandOffset(bytecode, i)];
     switch (op_type) {
       case interpreter::OperandType::kRegCount8:
         os << "#" << static_cast<unsigned int>(*operand_start);
         break;
@@ skipping 203 matching lines @@
   } else {
     std::ostringstream s;
     s << "r" << index();
     return s.str();
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8