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| author | Vedant Kumar <vsk@apple.com> | 2019-01-04 17:43:22 +0000 |
|---|---|---|
| committer | Vedant Kumar <vsk@apple.com> | 2019-01-04 17:43:22 +0000 |
| commit | a1778df4740fc690cbab62ec74342795b84a9a5c (patch) | |
| tree | fabe87231f1cbac065c7b3643171153f65cb9840 /llvm/test/Transforms/CodeExtractor | |
| parent | 722466e1f176f22d2339acb750f93498964b07ee (diff) | |
| download | bcm5719-llvm-a1778df4740fc690cbab62ec74342795b84a9a5c.tar.gz bcm5719-llvm-a1778df4740fc690cbab62ec74342795b84a9a5c.zip | |
[CodeExtractor] Do not extract unsafe lifetime markers
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
Diffstat (limited to 'llvm/test/Transforms/CodeExtractor')
| -rw-r--r-- | llvm/test/Transforms/CodeExtractor/PartialInlineAlloca4.ll | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/CodeExtractor/PartialInlineAlloca5.ll | 1 |
2 files changed, 5 insertions, 2 deletions
diff --git a/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca4.ll b/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca4.ll index 6bb38d44f46..04789eaad29 100644 --- a/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca4.ll +++ b/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca4.ll @@ -6,10 +6,14 @@ @g = external local_unnamed_addr global i32, align 4 +; CHECK-LABEL: define{{.*}}@caller( +; CHECK: call void @llvm.lifetime.start.p0i8(i64 -1, i8* %tmp.i) +; CHECK-NEXT: call void @callee_unknown_use1.{{.*}}(i8* %tmp.i +; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 -1, i8* %tmp.i) + define i32 @callee_unknown_use1(i32 %arg) local_unnamed_addr #0 { ; CHECK-LABEL:define{{.*}}@callee_unknown_use1.{{[0-9]}} ; CHECK-NOT: alloca -; CHECK: call void @llvm.lifetime bb: %tmp = alloca i8, align 4 %tmp2 = load i32, i32* @g, align 4, !tbaa !2 diff --git a/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca5.ll b/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca5.ll index 9c53496e1ce..0bde58fbccd 100644 --- a/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca5.ll +++ b/llvm/test/Transforms/CodeExtractor/PartialInlineAlloca5.ll @@ -9,7 +9,6 @@ define i32 @callee_unknown_use2(i32 %arg) local_unnamed_addr #0 { ; CHECK-LABEL:define{{.*}}@callee_unknown_use2.{{[0-9]}} ; CHECK-NOT: alloca -; CHECK: call void @llvm.lifetime bb: %tmp = alloca i32, align 4 %tmp1 = bitcast i32* %tmp to i8* |
