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Unified Diff: src/ia32/ic-ia32.cc

Issue 5763004: Second attempt: Improve our type feedback by recogizining never-executed IC c... (Closed) Base URL: http://v8.googlecode.com/svn/branches/bleeding_edge/
Patch Set: '' Created 10 years ago
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Index: src/ia32/ic-ia32.cc
===================================================================
--- src/ia32/ic-ia32.cc (revision 6011)
+++ src/ia32/ic-ia32.cc (working copy)
@@ -2049,13 +2049,23 @@
}
+static bool HasInlinedSmiCode(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.
+ return *test_instruction_address == Assembler::kTestAlByte;
+}
+
+
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, HasInlinedSmiCode(address()), x, y);
if (state == GENERIC) {
CompareStub stub(GetCondition(), strict(), NO_COMPARE_FLAGS);
rewritten = stub.GetCode();
@@ -2073,9 +2083,47 @@
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 a
+ // short jump-if-carry/not-carry at this position.
+ Address jmp_address = test_instruction_address - delta;
+ ASSERT(*jmp_address == Assembler::kJncShortOpcode ||
+ *jmp_address == Assembler::kJcShortOpcode);
+ Condition cc = *jmp_address == Assembler::kJncShortOpcode
Vitaly Repeshko 2010/12/15 12:18:50 Nit: "(*jmp_address == Assembler::kJncShortOpcode
+ ? not_zero
+ : zero;
+ *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
+}
+
+
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_IA32
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