Improve our type feedback by recogizining never-executed IC calls for binary ...

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
===================================================================
--- src/ia32/ic-ia32.cc	(revision 5966)
+++ src/ia32/ic-ia32.cc	(working copy)
@@ -2052,10 +2052,9 @@
 void CompareIC::UpdateCaches(Handle<Object> x, Handle<Object> y) {
   HandleScope scope;
   Handle<Code> rewritten;
-#ifdef DEBUG
   State previous_state = GetState();
-#endif
-  State state = TargetState(x, y);
+
+  State state = TargetState(previous_state, x, y);
   if (state == GENERIC) {
     CompareStub stub(GetCondition(), strict(), NO_COMPARE_FLAGS);
     rewritten = stub.GetCode();
@@ -2073,9 +2072,43 @@
            Token::Name(op_));
   }
 #endif
+
+  // Activate inlined smi code.
+  if (previous_state == UNINITIALIZED) {
+    PatchInlinedSmiCode(address());
+  }
 }
 
 
+void PatchInlinedSmiCode(Address address) {
+  // The address of the instruction following the call.
+  Address test_instruction_address =
+      address + Assembler::kCallTargetAddressOffset;
+
+  // If the instruction following the call is not a test al, nothing
+  // was inlined.
+  if (*test_instruction_address != Assembler::kTestAlByte) {
+    ASSERT(*test_instruction_address == Assembler::kNopByte);
+    return;
+  }
+
+  Address delta_address = test_instruction_address + 1;
+  // The delta to the start of the map check instruction and the
+  // condition code uses at the patched jump.
+  int8_t delta = *reinterpret_cast<int8_t*>(delta_address);
+  if (FLAG_trace_ic) {
+    PrintF("[  patching ic at %p, test=%p, delta=%d\n",
+           address, test_instruction_address, delta);
+  }
+
+  // Patch with a short conditional jump. There must be an unconditional
+  // short jump at this position.
+  Address jmp_address = test_instruction_address - delta;
+  ASSERT(*jmp_address == Assembler::kJmpShortOpcode);
+  *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | not_zero);
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32