Fix issue 974.

src/full-codegen.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 928 matching lines @@
   __ bind(&done);
   PrepareForBailoutForId(stmt->id(), NO_REGISTERS);
 }
 
 
 void FullCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
   Comment cmnt(masm_,  "[ ContinueStatement");
   SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
+  // When continuing, we clobber the unpredictable value in the accumulator
+  // with one that's safe for GC.  If we hit an exit from the try block of
+  // try...finally on our way out, we will unconditionally preserve the
+  // accumulator on the stack.
+  ClearAccumulator();
   while (!current->IsContinueTarget(stmt->target())) {
     stack_depth = current->Exit(stack_depth);
     current = current->outer();
   }
   __ Drop(stack_depth);
 
   Iteration* loop = current->AsIteration();
   __ jmp(loop->continue_target());
 }
 
 
 void FullCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
   Comment cmnt(masm_,  "[ BreakStatement");
   SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
+  // When breaking, we clobber the unpredictable value in the accumulator
+  // with one that's safe for GC.  If we hit an exit from the try block of
+  // try...finally on our way out, we will unconditionally preserve the
+  // accumulator on the stack.
+  ClearAccumulator();
   while (!current->IsBreakTarget(stmt->target())) {
     stack_depth = current->Exit(stack_depth);
     current = current->outer();
   }
   __ Drop(stack_depth);
 
   Breakable* target = current->AsBreakable();
   __ jmp(target->break_target());
 }
 
@@ skipping 253 matching lines @@
   }
 
   __ bind(&try_handler_setup);
   {
     // Setup try handler (stack pointer registers).
     TryFinally try_block(this, &finally_entry);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
     Visit(stmt->try_block());
     __ PopTryHandler();
   }
-  // Execute the finally block on the way out.
+  // Execute the finally block on the way out.  Clobber the unpredictable
+  // value in the accumulator with one that's safe for GC.  The finally
+  // block will unconditionally preserve the accumulator on the stack.
+  ClearAccumulator();
   __ Call(&finally_entry);
 }
 
 
 void FullCodeGenerator::VisitDebuggerStatement(DebuggerStatement* stmt) {
 #ifdef ENABLE_DEBUGGER_SUPPORT
   Comment cmnt(masm_, "[ DebuggerStatement");
   SetStatementPosition(stmt);
 
   __ DebugBreak();
@@ skipping 99 matching lines @@
   __ Drop(stack_depth);
   __ PopTryHandler();
   return 0;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal