More simplification and unification of frame handling

src/crankshaft/ia32/lithium-ia32.cc

Index: src/crankshaft/ia32/lithium-ia32.cc
diff --git a/src/crankshaft/ia32/lithium-ia32.cc b/src/crankshaft/ia32/lithium-ia32.cc
index 130ac852d33bfe6490b6c62de717ebe8a314c82d..724562f0559640d5caf065a68d752d21918d0f87 100644
--- a/src/crankshaft/ia32/lithium-ia32.cc
+++ b/src/crankshaft/ia32/lithium-ia32.cc
@@ -344,11 +344,11 @@ void LAccessArgumentsAt::PrintDataTo(StringStream* stream) {
 int LPlatformChunk::GetNextSpillIndex(RegisterKind kind) {
   // Skip a slot if for a double-width slot.
   if (kind == DOUBLE_REGISTERS) {
-    spill_slot_count_++;
-    spill_slot_count_ |= 1;
+    current_frame_slots_++;
+    current_frame_slots_ |= 1;
     num_double_slots_++;
   }
-  return spill_slot_count_++;
+  return current_frame_slots_++;
 }
 
 
@@ -2512,6 +2512,7 @@ LInstruction* LChunkBuilder::DoUnknownOSRValue(HUnknownOSRValue* instr) {
       // The first local is saved at the end of the unoptimized frame.
       spill_index = graph()->osr()->UnoptimizedFrameSlots();
     }
+    spill_index += StandardFrameConstants::kFixedSlotCount;
   }
   return DefineAsSpilled(new(zone()) LUnknownOSRValue, spill_index);
 }