a1778df474
Lifetime markers which reference inputs to the extraction region are not
safe to extract. Example ('rhs' will be extracted):
```
entry:
+------------+
| x = alloca |
| y = alloca |
+------------+
/ \
lhs: rhs:
+-------------------+ +-------------------+
| lifetime_start(x) | | lifetime_start(x) |
| use(x) | | lifetime_start(y) |
| lifetime_end(x) | | use(x, y) |
| lifetime_start(y) | | lifetime_end(y) |
| use(y) | | lifetime_end(x) |
| lifetime_end(y) | +-------------------+
+-------------------+
```
Prior to extraction, the stack coloring pass sees that the slots for 'x'
and 'y' are in-use at the same time. After extraction, the coloring pass
infers that 'x' and 'y' are *not* in-use concurrently, because markers
from 'rhs' are no longer available to help decide otherwise.
This leads to a miscompile, because the stack slots actually are in-use
concurrently in the extracted function.
Fix this by moving lifetime start/end markers for memory regions defined
in the calling function around the call to the extracted function.
Fixes llvm.org/PR39671 (rdar://45939472).
Differential Revision: https://reviews.llvm.org/D55967
llvm-svn: 350420
67 lines
2.0 KiB
LLVM
67 lines
2.0 KiB
LLVM
; RUN: opt < %s -partial-inliner -skip-partial-inlining-cost-analysis -S | FileCheck %s
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; RUN: opt < %s -passes=partial-inliner -skip-partial-inlining-cost-analysis -S | FileCheck %s
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%"class.base" = type { %"struct.base"* }
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%"struct.base" = type opaque
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@g = external local_unnamed_addr global i32, align 4
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define i32 @callee_unknown_use2(i32 %arg) local_unnamed_addr #0 {
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; CHECK-LABEL:define{{.*}}@callee_unknown_use2.{{[0-9]}}
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; CHECK-NOT: alloca
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bb:
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%tmp = alloca i32, align 4
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%tmp1 = bitcast i32* %tmp to i8*
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%tmp2 = load i32, i32* @g, align 4, !tbaa !2
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%tmp3 = add nsw i32 %tmp2, 1
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%tmp4 = icmp slt i32 %arg, 0
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br i1 %tmp4, label %bb6, label %bb5
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bb5: ; preds = %bb
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call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %tmp1) #2
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store i32 %tmp3, i32* %tmp, align 4, !tbaa !2
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store i32 %tmp3, i32* @g, align 4, !tbaa !2
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call void @bar(i32* nonnull %tmp) #2
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call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %tmp1) #2
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br label %bb6
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bb6: ; preds = %bb5, %bb
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%tmp7 = phi i32 [ 1, %bb5 ], [ 0, %bb ]
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%tmp10 = bitcast i8* %tmp1 to i32*
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ret i32 %tmp7
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}
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
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declare void @bar(i32*) local_unnamed_addr #2
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declare void @bar2(i32*, i32*) local_unnamed_addr #1
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
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; Function Attrs: nounwind uwtable
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define i32 @caller(i32 %arg) local_unnamed_addr #0 {
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bb:
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%tmp = tail call i32 @callee_unknown_use2(i32 %arg)
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ret i32 %tmp
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}
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attributes #0 = { nounwind uwtable}
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attributes #1 = { argmemonly nounwind }
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attributes #2 = { nounwind }
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!llvm.module.flags = !{!0}
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!llvm.ident = !{!1}
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!0 = !{i32 1, !"wchar_size", i32 4}
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!1 = !{!"clang version 5.0.0 (trunk 303574)"}
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!2 = !{!3, !3, i64 0}
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!3 = !{!"int", !4, i64 0}
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!4 = !{!"omnipotent char", !5, i64 0}
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!5 = !{!"Simple C/C++ TBAA"}
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