Generate a custom OSR entrypoint for OSR compiles on all platforms, and transition to optimized cod…

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 8c8103f61996e9f9a4604dc32a7ce3f4c4b39066..4cd6121e4ba5bb1e3460bb04a9b07409fa975cfa 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -32,6 +32,7 @@
 #include "lithium-allocator-inl.h"
 #include "ia32/lithium-ia32.h"
 #include "ia32/lithium-codegen-ia32.h"
+#include "hydrogen-osr.h"
 
 namespace v8 {
 namespace internal {
@@ -493,6 +494,14 @@ LPlatformChunk* LChunkBuilder::Build() {
     USE(alignment_state_index);
   }
 
+  // If compiling for OSR, reserve space for the unoptimized frame,
+  // which will be subsumed into this frame.
+  if (graph()->has_osr()) {
+    for (int i = graph()->osr()->UnoptimizedFrameSlots(); i > 0; i--) {
+      chunk_->GetNextSpillIndex(false);
+    }
+  }
+
   const ZoneList<HBasicBlock*>* blocks = graph()->blocks();
   for (int i = 0; i < blocks->length(); i++) {
     HBasicBlock* next = NULL;
@@ -2597,10 +2606,23 @@ LInstruction* LChunkBuilder::DoParameter(HParameter* instr) {
 
 
 LInstruction* LChunkBuilder::DoUnknownOSRValue(HUnknownOSRValue* instr) {
-  int spill_index = chunk()->GetNextSpillIndex(false);  // Not double-width.
-  if (spill_index > LUnallocated::kMaxFixedSlotIndex) {
-    Abort("Too many spill slots needed for OSR");
-    spill_index = 0;
+  // Use an index that corresponds to the location in the unoptimized frame,
+  // which the optimized frame will subsume.
+  int env_index = instr->index();
+  int spill_index = 0;
+  if (instr->environment()->is_parameter_index(env_index)) {
+    spill_index = chunk()->GetParameterStackSlot(env_index);
+  } else {
+    spill_index = env_index - instr->environment()->first_local_index();
+    if (spill_index > LUnallocated::kMaxFixedSlotIndex) {
+      Abort("Too many spill slots needed for OSR");
+      spill_index = 0;
+    }
+    if (spill_index == 0) {
+      // The dynamic frame alignment state overwrites the first local.
+      // The first local is saved at the end of the unoptimized frame.
+      spill_index = graph()->osr()->UnoptimizedFrameSlots();
+    }
   }
   return DefineAsSpilled(new(zone()) LUnknownOSRValue, spill_index);
 }