151ed6aa38
Add -tsan-instrument-read-before-write which allows instrumenting reads
of reads-before-writes.
This is required for KCSAN [1], where under certain configurations plain
writes behave differently (e.g. aligned writes up to word size may be
treated as atomic). In order to avoid missing potential data races due
to plain RMW operations ("x++" etc.), we will require instrumenting
reads of reads-before-writes.
[1] https://github.com/google/ktsan/wiki/KCSAN
Author: melver (Marco Elver)
Reviewed-in: https://reviews.llvm.org/D79983
35 lines
1020 B
LLVM
35 lines
1020 B
LLVM
; RUN: opt < %s -tsan -S | FileCheck %s
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; RUN: opt < %s -tsan -tsan-instrument-read-before-write -S | FileCheck %s --check-prefixes=CHECK,CHECK-UNOPT
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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define void @IncrementMe(i32* nocapture %ptr) nounwind uwtable sanitize_thread {
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entry:
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%0 = load i32, i32* %ptr, align 4
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%inc = add nsw i32 %0, 1
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store i32 %inc, i32* %ptr, align 4
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ret void
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}
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; CHECK: define void @IncrementMe
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; CHECK-NOT: __tsan_read
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; CHECK-UNOPT: __tsan_read
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; CHECK: __tsan_write
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; CHECK: ret void
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define void @IncrementMeWithCallInBetween(i32* nocapture %ptr) nounwind uwtable sanitize_thread {
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entry:
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%0 = load i32, i32* %ptr, align 4
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%inc = add nsw i32 %0, 1
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call void @foo()
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store i32 %inc, i32* %ptr, align 4
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ret void
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}
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; CHECK: define void @IncrementMeWithCallInBetween
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; CHECK: __tsan_read
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; CHECK: __tsan_write
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; CHECK: ret void
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declare void @foo()
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