Thread sanitizer instrumentation fails to skip all loads and stores to
profile counters. This can happen if profile counter updates are merged:
%.sink = phi i64* ...
%pgocount5 = load i64, i64* %.sink
%27 = add i64 %pgocount5, 1
%28 = bitcast i64* %.sink to i8*
call void @__tsan_write8(i8* %28)
store i64 %27, i64* %.sink
To suppress TSan diagnostics about racy counter updates, make the
counter updates atomic when TSan is enabled. If there's general interest
in this mode it can be surfaced as a clang/swift driver option.
Testing: check-{llvm,clang,profile}
rdar://
40477803
Differential Revision: https://reviews.llvm.org/D50867
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@339955
91177308-0d34-0410-b5e6-
96231b3b80d8
InstrProfOptions Options;
Options.NoRedZone = CodeGenOpts.DisableRedZone;
Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
+
+ // TODO: Surface the option to emit atomic profile counter increments at
+ // the driver level.
+ Options.Atomic = LangOpts.Sanitize.has(SanitizerKind::Thread);
+
MPM.add(createInstrProfilingLegacyPass(Options));
}
if (CodeGenOpts.hasProfileIRInstr()) {
--- /dev/null
+// RUN: %clang_cc1 %s -emit-llvm -fprofile-instrument=clang -fsanitize=thread -o - | FileCheck %s
+
+// CHECK: define void @foo
+// CHECK-NOT: load {{.*}}foo
+// CHECK: ret void
+void foo() {}