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| author | Kostya Serebryany <kcc@google.com> | 2012-04-10 22:29:17 +0000 |
|---|---|---|
| committer | Kostya Serebryany <kcc@google.com> | 2012-04-10 22:29:17 +0000 |
| commit | cff60c1409e36079b4bc6ecbda84565143bf00af (patch) | |
| tree | 37ee207e2155b163af6bc0da9fa27ebccbe92a1d /test/Instrumentation | |
| parent | 3aef2ff514c879f98571fb91ddbe1142466a6266 (diff) | |
| download | llvm-cff60c1409e36079b4bc6ecbda84565143bf00af.tar.gz llvm-cff60c1409e36079b4bc6ecbda84565143bf00af.tar.bz2 llvm-cff60c1409e36079b4bc6ecbda84565143bf00af.tar.xz | |
[tsan] two more compile-time optimizations:
- don't isntrument reads from constant globals.
Saves ~1.5% of instrumented instructions on CPU2006
(counting static instructions, not their execution).
- don't insrument reads from vtable (which is a global constant too).
Saves ~5%.
I did not measure the run-time impact of this,
but it is certainly non-negative.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154444 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Instrumentation')
| -rw-r--r-- | test/Instrumentation/ThreadSanitizer/read_from_global.ll | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/test/Instrumentation/ThreadSanitizer/read_from_global.ll b/test/Instrumentation/ThreadSanitizer/read_from_global.ll new file mode 100644 index 0000000000..a08453ac4a --- /dev/null +++ b/test/Instrumentation/ThreadSanitizer/read_from_global.ll @@ -0,0 +1,61 @@ +; RUN: opt < %s -tsan -S | FileCheck %s +; Check that tsan does not instrument reads from constant globals. + +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" + +@const_global = external constant i32 +define i32 @read_from_const_global() nounwind uwtable readnone { +entry: + %0 = load i32* @const_global, align 4 + ret i32 %0 +} +; CHECK: define i32 @read_from_const_global +; CHECK-NOT: __tsan +; CHECK: ret i32 + +@non_const_global = global i32 0, align 4 +define i32 @read_from_non_const_global() nounwind uwtable readonly { +entry: + %0 = load i32* @non_const_global, align 4 + ret i32 %0 +} + +; CHECK: define i32 @read_from_non_const_global +; CHECK: __tsan_read +; CHECK: ret i32 + +@const_global_array = external constant [10 x i32] +define i32 @read_from_const_global_array(i32 %idx) nounwind uwtable readnone { +entry: + %idxprom = sext i32 %idx to i64 + %arrayidx = getelementptr inbounds [10 x i32]* @const_global_array, i64 0, i64 %idxprom + %0 = load i32* %arrayidx, align 4 + ret i32 %0 +} + +; CHECK: define i32 @read_from_const_global_array +; CHECK-NOT: __tsan +; CHECK: ret i32 + +%struct.Foo = type { i32 (...)** } +define void @call_virtual_func(%struct.Foo* %f) uwtable { +entry: + %0 = bitcast %struct.Foo* %f to void (%struct.Foo*)*** + %vtable = load void (%struct.Foo*)*** %0, align 8, !tbaa !3 + %1 = load void (%struct.Foo*)** %vtable, align 8 + call void %1(%struct.Foo* %f) + ret void +} + +; CHECK: define void @call_virtual_func +; CHECK: __tsan_read +; CHECK: = load +; CHECK-NOT: __tsan_read +; CHECK: = load +; CHECK: ret void + +!0 = metadata !{metadata !"int", metadata !1} +!1 = metadata !{metadata !"omnipotent char", metadata !2} +!2 = metadata !{metadata !"Simple C/C++ TBAA", null} +!3 = metadata !{metadata !"vtable pointer", metadata !2} + |