forked from OSchip/llvm-project
[tsan] disable load widening in ThreadSanitizer mode
llvm-svn: 175034
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@ -284,6 +284,12 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs,
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// We can only extend simple integer loads.
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if (!isa<IntegerType>(LI->getType()) || !LI->isSimple()) return 0;
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// Load widening is hostile to ThreadSanitizer: it may cause false positives
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// or make the reports more cryptic (access sizes are wrong).
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if (LI->getParent()->getParent()->getAttributes().
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hasAttribute(AttributeSet::FunctionIndex, Attribute::ThreadSafety))
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return 0;
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// Get the base of this load.
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int64_t LIOffs = 0;
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const Value *LIBase =
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@ -0,0 +1,26 @@
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; RUN: opt < %s -basicaa -gvn -tsan -S | FileCheck %s
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; TSAN conflicts with load widening. Make sure the load widening is off with -tsan.
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; 32-bit little endian target.
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target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
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%struct_of_8_bytes_4_aligned = type { i32, i8, i8, i8, i8}
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@f = global %struct_of_8_bytes_4_aligned zeroinitializer, align 4
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; Accessing bytes 4 and 6, not ok to widen to i32 if thread_safety is set.
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define i32 @test_widening_bad(i8* %P) nounwind ssp noredzone thread_safety {
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entry:
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%tmp = load i8* getelementptr inbounds (%struct_of_8_bytes_4_aligned* @f, i64 0, i32 1), align 4
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%conv = zext i8 %tmp to i32
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%tmp1 = load i8* getelementptr inbounds (%struct_of_8_bytes_4_aligned* @f, i64 0, i32 3), align 1
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%conv2 = zext i8 %tmp1 to i32
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%add = add nsw i32 %conv, %conv2
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ret i32 %add
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; CHECK: @test_widening_bad
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; CHECK: call void @__tsan_read1
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; CHECK: call void @__tsan_read1
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; CHECK-NOT: call void @__tsan_read4
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; CHECK: ret i32
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}
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