MIPS: Elide unnecessary context reload in generated stubs.

src/mips/lithium-codegen-mips.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 2442 matching lines @@
     // Runtime::TraceExit returns its parameter in v0.
     __ push(v0);
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
   if (NeedsEagerFrame()) {
     int32_t sp_delta = (GetParameterCount() + 1) * kPointerSize;
     __ mov(sp, fp);
     __ Pop(ra, fp);
     __ Addu(sp, sp, Operand(sp_delta));
   }
-  if (info()->IsStub()) {
-    __ lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
-  }
   __ Jump(ra);
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ li(at, Operand(Handle<Object>(instr->hydrogen()->cell())));
   __ lw(result, FieldMemOperand(at, JSGlobalPropertyCell::kValueOffset));
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
@@ skipping 3312 matching lines @@
   __ Subu(scratch, result, scratch);
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal