MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
EmitAndCountInstruction(TmpInst);
+
+ // Stackmap shadows cannot include branch targets, so we can count the bytes
+ // in a call towards the shadow, but must flush the shadow immediately after
+ // to account for the return from the call.
+ if (MI->isCall())
+ SMShadowTracker.emitShadowPadding(OutStreamer, getSubtargetInfo());
}
; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck %s
-; Check that the X86 stackmap shadow optimization is only outputting a 1-byte
-; nop here. 8-bytes are requested, but 7 are covered by the code for the call to
-; bar, the frame teardown and the return.
+; Check that the X86 stackmap shadow optimization is only outputting a 3-byte
+; nop here. 8-bytes are requested, but 5 are covered by the code for the call to
+; bar. However, the frame teardown and the return do not count towards the
+; stackmap shadow as the call return counts as a branch target so must flush
+; the shadow.
define void @shadow_optimization_test() {
entry:
; CHECK-LABEL: shadow_optimization_test:
; CHECK: callq _bar
; CHECK-NOT: nop
; CHECK: callq _bar
-; CHECK: retq
; CHECK: nop
+; CHECK: retq
call void @bar()
tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 8)
call void @bar()