[turbofan] Add DebugBreak machine operator and support

src/compiler/instruction-scheduler.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/compiler/instruction-scheduler.h"
 
 #include "src/base/adapters.h"
 #include "src/base/utils/random-number-generator.h"
 
 namespace v8 {
@@ skipping 204 matching lines @@
 }
 
 
 int InstructionScheduler::GetInstructionFlags(const Instruction* instr) const {
   switch (instr->arch_opcode()) {
     case kArchNop:
     case kArchFramePointer:
     case kArchParentFramePointer:
     case kArchTruncateDoubleToI:
     case kArchStackSlot:
+    case kArchDebugBreak:
       return kNoOpcodeFlags;
 
     case kArchStackPointer:
       // ArchStackPointer instruction loads the current stack pointer value and
       // must not be reordered with instruction with side effects.
       return kIsLoadOperation;
 
     case kArchPrepareCallCFunction:
     case kArchPrepareTailCall:
     case kArchCallCFunction:
@@ skipping 102 matching lines @@
       }
     }
 
     node->set_total_latency(max_latency + node->latency());
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8