Fix a crash in graoh builder where a throw node is added in an expression tree by the parser: allow…

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, 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 1168 matching lines @@
   Value* value_;
   intptr_t token_index_;
 
   DISALLOW_COPY_AND_ASSIGN(ReturnInstr);
 };
 
 
 class ThrowInstr : public Instruction {
  public:
   ThrowInstr(intptr_t node_id, intptr_t token_index, Value* exception)
-      : node_id_(node_id), token_index_(token_index), exception_(exception) {
+      : node_id_(node_id),
+        token_index_(token_index),
+        exception_(exception),
+        successor_(NULL) {
     ASSERT(exception_ != NULL);
   }
 
   DECLARE_INSTRUCTION(Throw)
 
   intptr_t node_id() const { return node_id_; }
   intptr_t token_index() const { return token_index_; }
   Value* exception() const { return exception_; }
 
-  virtual Instruction* StraightLineSuccessor() const { return NULL; }
-  virtual void SetSuccessor(Instruction* instr) { UNREACHABLE(); }
+  // Parser can generate a throw within an expression tree.
+  virtual Instruction* StraightLineSuccessor() const {
+    return successor_;
+  }
+  virtual void SetSuccessor(Instruction* instr) {
+    ASSERT(successor_ == NULL);
+    successor_ = instr;
+  }
 
  private:
   intptr_t node_id_;
   intptr_t token_index_;
   Value* exception_;
+  Instruction* successor_;
 
   DISALLOW_COPY_AND_ASSIGN(ThrowInstr);
 };
 
 
 class ReThrowInstr : public Instruction {
  public:
   ReThrowInstr(intptr_t node_id,
               intptr_t token_index,
               Value* exception,
               Value* stack_trace)
       : node_id_(node_id),
         token_index_(token_index),
         exception_(exception),
-        stack_trace_(stack_trace) {
+        stack_trace_(stack_trace),
+        successor_(NULL) {
     ASSERT(exception_ != NULL);
     ASSERT(stack_trace_ != NULL);
   }
 
   DECLARE_INSTRUCTION(ReThrow)
 
   intptr_t node_id() const { return node_id_; }
   intptr_t token_index() const { return token_index_; }
   Value* exception() const { return exception_; }
   Value* stack_trace() const { return stack_trace_; }
 
-  virtual Instruction* StraightLineSuccessor() const { return NULL; }
-  virtual void SetSuccessor(Instruction* instr) { UNREACHABLE(); }
+  // Parser can generate a rethrow within an expression tree.
+  virtual Instruction* StraightLineSuccessor() const {
+    return successor_;
+  }
+  virtual void SetSuccessor(Instruction* instr) {
+    ASSERT(successor_ == NULL);
+    successor_ = instr;
+  }
 
  private:
   intptr_t node_id_;
   intptr_t token_index_;
   Value* exception_;
   Value* stack_trace_;
+  Instruction* successor_;
 
   DISALLOW_COPY_AND_ASSIGN(ReThrowInstr);
 };
 
 
 class BranchInstr : public Instruction {
  public:
   explicit BranchInstr(Value* value)
       : value_(value),
         true_successor_(NULL),
@@ skipping 65 matching lines @@
   const GrowableArray<BlockEntryInstr*>& block_order_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_