[crankshaft] Generate lazy bailout point for HProlog instruction only when it is necessary.

src/crankshaft/x87/lithium-x87.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.
 
 #include "src/crankshaft/x87/lithium-x87.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_X87
 
@@ skipping 906 matching lines @@
     // TODO(olivf) Since phis of spilled values are joined as registers
     // (not in the stack slot), we need to allow the goto gaps to keep one
     // x87 register alive. To ensure all other values are still spilled, we
     // insert a fpu register barrier right before.
     LClobberDoubles* clobber = new(zone()) LClobberDoubles(isolate());
     clobber->set_hydrogen_value(hydrogen_val);
     chunk_->AddInstruction(clobber, current_block_);
   }
   chunk_->AddInstruction(instr, current_block_);
 
-  if (instr->IsCall() || instr->IsPrologue()) {
+  if (instr->IsCall()) {
     HValue* hydrogen_value_for_lazy_bailout = hydrogen_val;
     if (hydrogen_val->HasObservableSideEffects()) {
       HSimulate* sim = HSimulate::cast(hydrogen_val->next());
       sim->ReplayEnvironment(current_block_->last_environment());
       hydrogen_value_for_lazy_bailout = sim;
     }
     LInstruction* bailout = AssignEnvironment(new(zone()) LLazyBailout());
     bailout->set_hydrogen_value(hydrogen_value_for_lazy_bailout);
     chunk_->AddInstruction(bailout, current_block_);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoPrologue(HPrologue* instr) {
-  return new (zone()) LPrologue();
+  LInstruction* result = new (zone()) LPrologue();
+  if (info_->num_heap_slots() > 0) {
+    result = MarkAsCall(result, instr);
+  }
+  return result;
 }
 
 
 LInstruction* LChunkBuilder::DoGoto(HGoto* instr) {
   return new(zone()) LGoto(instr->FirstSuccessor());
 }
 
 
 LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
   HValue* value = instr->value();
@@ skipping 1650 matching lines @@
 LInstruction* LChunkBuilder::DoStoreFrameContext(HStoreFrameContext* instr) {
   LOperand* context = UseRegisterAtStart(instr->context());
   return new(zone()) LStoreFrameContext(context);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87