[x64] Fix crashes in CheckAccessGlobalProxy

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 4561 matching lines @@
 
   DCHECK(!holder_reg.is(scratch));
   DCHECK(!scratch.is(kScratchRegister));
   // Load current lexical context from the active StandardFrame, which
   // may require crawling past STUB frames.
   Label load_context;
   Label has_context;
   movp(scratch, rbp);
   bind(&load_context);
   DCHECK(SmiValuesAre32Bits());
-  int smi_tag_offset = kSmiShift / kBitsPerByte;
-  cmpl(MemOperand(scratch, CommonFrameConstants::kContextOrFrameTypeOffset +
-                               smi_tag_offset),
-       Immediate(StackFrame::STUB));
+  // This is "JumpIfNotSmi" but without loading the value into a register.
+  cmpl(MemOperand(scratch, CommonFrameConstants::kContextOrFrameTypeOffset),
+       Immediate(0));
   j(not_equal, &has_context);
   movp(scratch, MemOperand(scratch, CommonFrameConstants::kCallerFPOffset));
   jmp(&load_context);
   bind(&has_context);
   movp(scratch,
        MemOperand(scratch, CommonFrameConstants::kContextOrFrameTypeOffset));
 
   // When generating debug code, make sure the lexical context is set.
   if (emit_debug_code()) {
     cmpp(scratch, Immediate(0));
@@ skipping 1069 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64