llvm/test/Transforms/InstCombine/lifetime-asan.ll
Vitaly Buka 2328afe0b5 Do not remove empty lifetime.start/lifetime.end ranges
Summary:
Asan stack-use-after-scope check should poison alloca even if there is
no access between start and end.

This is possible for code like this:
for (int i = 0; i < 3; i++) {
  int x;
  p = &x;
}

"Loop Invariant Code Motion" will move "p = &x;" out of the loop, making
start/end range empty.

PR27453

Reviewers: eugenis

Differential Revision: https://reviews.llvm.org/D22842

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277072 91177308-0d34-0410-b5e6-96231b3b80d8
2016-07-28 22:59:03 +00:00

36 lines
831 B
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
declare void @llvm.lifetime.start(i64, i8* nocapture)
declare void @llvm.lifetime.end(i64, i8* nocapture)
declare void @foo(i8* nocapture)
define void @asan() sanitize_address {
entry:
; CHECK-LABEL: @asan(
%text = alloca i8, align 1
call void @llvm.lifetime.start(i64 1, i8* %text)
call void @llvm.lifetime.end(i64 1, i8* %text)
; CHECK: call void @llvm.lifetime.start
; CHECK-NEXT: call void @llvm.lifetime.end
call void @foo(i8* %text) ; Keep alloca alive
ret void
}
define void @no_asan() {
entry:
; CHECK-LABEL: @no_asan(
%text = alloca i8, align 1
call void @llvm.lifetime.start(i64 1, i8* %text)
call void @llvm.lifetime.end(i64 1, i8* %text)
; CHECK-NO: call void @llvm.lifetime
call void @foo(i8* %text) ; Keep alloca alive
ret void
}