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68aeef61f4
For a call to not return in to the stackmap shadow, the shadow must end with the call. To do this, we must insert any required nops *before* the call, and not after it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220728 91177308-0d34-0410-b5e6-96231b3b80d8
29 lines
1.0 KiB
LLVM
29 lines
1.0 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck %s
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; Check that the X86 stackmap shadow optimization is only outputting a 3-byte
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; nop here. 8-bytes are requested, but 5 are covered by the code for the call to
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; bar. However, the frame teardown and the return do not count towards the
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; stackmap shadow as the call return counts as a branch target so must flush
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; the shadow.
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; Note that in order for a thread to not return in to the patched space
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; the call must be at the end of the shadow, so the required nop must be
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; before the call, not after.
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define void @shadow_optimization_test() {
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entry:
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; CHECK-LABEL: shadow_optimization_test:
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; CHECK: callq _bar
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; CHECK: nop
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; CHECK: callq _bar
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; CHECK-NOT: nop
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; CHECK: callq _bar
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; CHECK-NOT: nop
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call void @bar()
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tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 8)
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call void @bar()
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call void @bar()
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ret void
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}
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declare void @llvm.experimental.stackmap(i64, i32, ...)
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declare void @bar()
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