Elide unnecessary context reload in generated stubs.

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 786 matching lines @@
     deoptimizations_.Add(environment, zone());
   }
 }
 
 
 void LCodeGen::DeoptimizeIf(Condition cc, LEnvironment* environment) {
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
   ASSERT(environment->HasBeenRegistered());
   int id = environment->deoptimization_index();
   ASSERT(info()->IsOptimizing() || info()->IsStub());
-  Deoptimizer::BailoutType bailout_type = frame_is_built_
+  Deoptimizer::BailoutType bailout_type = info()->IsOptimizing()

[ulan, 2012/12/28 15:40:49]

Maybe negate this and use info()->IsStub() to make it similar to x64 and arm?

[danno, 2012/12/28 17:38:41]

Done.

       ? Deoptimizer::EAGER
       : Deoptimizer::LAZY;
   Address entry = Deoptimizer::GetDeoptimizationEntry(id, bailout_type);
   if (entry == NULL) {
     Abort("bailout was not prepared");
     return;
   }
 
   if (FLAG_deopt_every_n_times != 0) {
     Handle<SharedFunctionInfo> shared(info_->shared_info());
@@ skipping 1815 matching lines @@
     __ j(equal, &no_padding);
     if (FLAG_debug_code) {
       __ cmp(Operand(esp, (GetParameterCount() + 2) * kPointerSize),
              Immediate(kAlignmentZapValue));
       __ Assert(equal, "expected alignment marker");
     }
     __ Ret((GetParameterCount() + 2) * kPointerSize, ecx);
     __ bind(&no_padding);
   }
   if (info()->IsStub()) {
-    __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
     __ Ret();
   } else {
     __ Ret((GetParameterCount() + 1) * kPointerSize, ecx);
   }
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ mov(result, Operand::Cell(instr->hydrogen()->cell()));
@@ skipping 714 matching lines @@
 
 
 void LCodeGen::DoThisFunction(LThisFunction* instr) {
   Register result = ToRegister(instr->result());
   __ mov(result, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
 }
 
 
 void LCodeGen::DoContext(LContext* instr) {
   Register result = ToRegister(instr->result());
-  __ mov(result, Operand(ebp, StandardFrameConstants::kContextOffset));
+  if (info()->IsOptimizing()) {
+    __ mov(result, Operand(ebp, StandardFrameConstants::kContextOffset));
+  } else {
+    // If there is no frame, the context must be in esi.
+    ASSERT(result.is(esi));
+  }
 }
 
 
 void LCodeGen::DoOuterContext(LOuterContext* instr) {
   Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
   __ mov(result,
          Operand(context, Context::SlotOffset(Context::PREVIOUS_INDEX)));
 }
 
@@ skipping 2541 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32