Add support for debug break in Dart source.

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 422 matching lines @@
   M(IndirectEntry)                                                             \
   M(CatchBlockEntry)                                                           \
   M(Phi)                                                                       \
   M(Redefinition)                                                              \
   M(Parameter)                                                                 \
   M(ParallelMove)                                                              \
   M(PushArgument)                                                              \
   M(Return)                                                                    \
   M(Throw)                                                                     \
   M(ReThrow)                                                                   \
+  M(Stop)                                                                      \
   M(Goto)                                                                      \
   M(IndirectGoto)                                                              \
   M(Branch)                                                                    \
   M(AssertAssignable)                                                          \
   M(AssertBoolean)                                                             \
   M(CurrentContext)                                                            \
   M(ClosureCall)                                                               \
   M(InstanceCall)                                                              \
   M(PolymorphicInstanceCall)                                                   \
   M(StaticCall)                                                                \
@@ skipping 1665 matching lines @@
   virtual EffectSet Effects() const { return EffectSet::None(); }
 
  private:
   const intptr_t token_pos_;
   const intptr_t catch_try_index_;
 
   DISALLOW_COPY_AND_ASSIGN(ReThrowInstr);
 };
 
 
+class StopInstr : public TemplateInstruction<0, NoThrow> {
+ public:
+  explicit StopInstr(const char* message)
+      : message_(message) {
+    ASSERT(message != NULL);
+  }
+
+  const char* message() const { return message_; }
+
+  DECLARE_INSTRUCTION(Stop);
+
+  virtual intptr_t ArgumentCount() const { return 0; }
+
+  virtual bool CanDeoptimize() const { return false; }
+
+  virtual EffectSet Effects() const { return EffectSet::None(); }
+
+  virtual EffectSet Dependencies() const { return EffectSet::None(); }
+
+ private:
+  const char* message_;
+
+  DISALLOW_COPY_AND_ASSIGN(StopInstr);
+};
+
+
 class GotoInstr : public TemplateInstruction<0, NoThrow> {
  public:
   explicit GotoInstr(JoinEntryInstr* entry)
     : TemplateInstruction(Isolate::Current()->GetNextDeoptId()),
       successor_(entry),
       edge_weight_(0.0),
       parallel_move_(NULL) {
   }
 
   DECLARE_INSTRUCTION(Goto)
@@ skipping 5937 matching lines @@
   LocationSummary* Name::MakeLocationSummary(Zone* zone, bool opt) const {    \
     UNIMPLEMENTED();                                                          \
     return NULL;                                                              \
   }                                                                           \
   void Name::EmitNativeCode(FlowGraphCompiler* compiler) { UNIMPLEMENTED(); }
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_