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

runtime/vm/flow_graph_builder.cc

 // 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.
 
 #include "vm/flow_graph_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/dart_entry.h"
 #include "vm/flags.h"
 #include "vm/intermediate_language.h"
@@ skipping 1825 matching lines @@
 void EffectGraphVisitor::VisitCatchClauseNode(CatchClauseNode* node) {
   Bailout("EffectGraphVisitor::VisitCatchClauseNode");
 }
 
 
 void EffectGraphVisitor::VisitTryCatchNode(TryCatchNode* node) {
   Bailout("EffectGraphVisitor::VisitTryCatchNode");
 }
 
 
-void EffectGraphVisitor::VisitThrowNode(ThrowNode* node) {
+void EffectGraphVisitor::BuildThrowNode(ThrowNode* node) {
   ValueGraphVisitor for_exception(owner(), temp_index());
   node->exception()->Visit(&for_exception);
   Append(for_exception);
   Instruction* instr = NULL;
   if (node->stacktrace() == NULL) {
     instr = new ThrowInstr(
         node->id(), node->token_index(), for_exception.value());
   } else {
     ValueGraphVisitor for_stack_trace(owner(), temp_index() + 1);
     node->stacktrace()->Visit(&for_stack_trace);
     Append(for_stack_trace);
     instr = new ReThrowInstr(node->id(),
                              node->token_index(),
                              for_exception.value(),
                              for_stack_trace.value());
   }
   AddInstruction(instr);
+}
+
+
+void EffectGraphVisitor::VisitThrowNode(ThrowNode* node) {
+  BuildThrowNode(node);
   CloseFragment();
 }
 
 
+// A throw cannot be part of an expression, however, the parser may replace
+// certain expression nodes with a throw. In that case generate a literal null
+// so that the fragment is not closed in the middle of an expression.
+void ValueGraphVisitor::VisitThrowNode(ThrowNode* node) {
+  BuildThrowNode(node);
+  ReturnValue(new ConstantVal(Instance::ZoneHandle()));
+}
+
+
 void EffectGraphVisitor::VisitInlinedFinallyNode(InlinedFinallyNode* node) {
   Bailout("EffectGraphVisitor::VisitInlinedFinallyNode");
 }
 
 
 // Graph printing.
 class FlowGraphPrinter : public FlowGraphVisitor {
  public:
   FlowGraphPrinter(const Function& function,
                    const GrowableArray<BlockEntryInstr*>& block_order)
@@ skipping 488 matching lines @@
   char* chars = reinterpret_cast<char*>(
       Isolate::Current()->current_zone()->Allocate(len));
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart