Fix mozilla regress-398085-01 failure on windows.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 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 119 matching lines @@
 
   // Copy the string before recording it in the assembler to avoid
   // issues when the stack allocated buffer goes out of scope.
   size_t length = builder.position();
   Vector<char> copy = Vector<char>::New(length + 1);
   OS::MemCopy(copy.start(), builder.Finalize(), copy.length());
   masm()->RecordComment(copy.start());
 }
 
 
+#ifdef _MSC_VER
+void LCodeGen::MakeSureStackPagesMapped(int offset) {
+  const int kPageSize = 4 * KB;
+  for (offset -= kPageSize; offset > 0; offset -= kPageSize) {
+    __ mov(Operand(esp, offset), eax);
+  }
+}
+#endif
+
+
 bool LCodeGen::GeneratePrologue() {
   ASSERT(is_generating());
 
   if (info()->IsOptimizing()) {
     ProfileEntryHookStub::MaybeCallEntryHook(masm_);
 
 #ifdef DEBUG
     if (strlen(FLAG_stop_at) > 0 &&
         info_->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
       __ int3();
@@ skipping 69 matching lines @@
   if (slots > 0) {
     if (slots == 1) {
       if (dynamic_frame_alignment_) {
         __ push(edx);
       } else {
         __ push(Immediate(kNoAlignmentPadding));
       }
     } else {
       if (FLAG_debug_code) {
         __ sub(Operand(esp), Immediate(slots * kPointerSize));
+#ifdef _MSC_VER
+        MakeSureStackPagesMapped(slots * kPointerSize);
+#endif
         __ push(eax);
         __ mov(Operand(eax), Immediate(slots));
         Label loop;
         __ bind(&loop);
         __ mov(MemOperand(esp, eax, times_4, 0),
                Immediate(kSlotsZapValue));
         __ dec(eax);
         __ j(not_zero, &loop);
         __ pop(eax);
       } else {
         __ sub(Operand(esp), Immediate(slots * kPointerSize));
 #ifdef _MSC_VER
-        // On windows, you may not access the stack more than one page below
-        // the most recently mapped page. To make the allocated area randomly
-        // accessible, we write to each page in turn (the value is irrelevant).
-        const int kPageSize = 4 * KB;
-        for (int offset = slots * kPointerSize - kPageSize;
-             offset > 0;
-             offset -= kPageSize) {
-          __ mov(Operand(esp, offset), eax);
-        }
+        MakeSureStackPagesMapped(slots * kPointerSize);
 #endif
       }
 
       if (support_aligned_spilled_doubles_) {
         Comment(";;; Store dynamic frame alignment tag for spilled doubles");
         // Store dynamic frame alignment state in the first local.
         int offset = JavaScriptFrameConstants::kDynamicAlignmentStateOffset;
         if (dynamic_frame_alignment_) {
           __ mov(Operand(ebp, offset), edx);
         } else {
@@ skipping 6246 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32