Fix stack pointer reset bug in entry to catch blocks.

vm/flow_graph_compiler_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "lib/error.h"
@@ skipping 1122 matching lines @@
 }
 
 
 // Restore stack and initialize the two exception variables:
 // exception and stack trace variables.
 void FlowGraphCompiler::VisitCatchEntry(CatchEntryComp* comp) {
   // Restore RSP from RBP as we are coming from a throw and the code for
   // popping arguments has not been run.
   const intptr_t locals_space_size = StackSize() * kWordSize;
   ASSERT(locals_space_size >= 0);
-  __ movq(RSP, RBP);
-  __ subq(RSP, Immediate(locals_space_size));
+  if (locals_space_size == 0) {
+    __ movq(RSP, RBP);
+  } else {
+    __ leaq(RSP, Address(RBP, -locals_space_size));
+  }
 
   ASSERT(!comp->exception_var().is_captured());
   ASSERT(!comp->stacktrace_var().is_captured());
   __ movq(Address(RBP, comp->exception_var().index() * kWordSize),
           kExceptionObjectReg);
   __ movq(Address(RBP, comp->stacktrace_var().index() * kWordSize),
           kStackTraceObjectReg);
 }
 
 
@@ skipping 567 matching lines @@
   ASSERT(exception_handlers_list_ != NULL);
   const ExceptionHandlers& handlers = ExceptionHandlers::Handle(
       exception_handlers_list_->FinalizeExceptionHandlers(code.EntryPoint()));
   code.set_exception_handlers(handlers);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64