Commit 87ac2975 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r276015: 

------------------------------------------------------------------------
r276015 | vedantk | 2016-07-19 13:16:08 -0700 (Tue, 19 Jul 2016) | 7 lines

[tsan] Don't instrument __llvm_gcov_global_state_pred or __llvm_gcda*

r274801 did not go far enough to allow gcov+tsan to cooperate. With this
commit it's possible to run the following code without false positives:

  std::thread T1(fib), T2(fib);
  T1.join(); T2.join();
------------------------------------------------------------------------

llvm-svn: 276810
parent 7bf9e46f

llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp

+3 −2
Original line number Diff line number Diff line
@@ -272,8 +272,9 @@ static bool shouldInstrumentReadWriteFromAddress(Value *Addr) { 
        return false;

    }



    // Check if the global is in a GCOV counter array.

    if (GV->getName().startswith("__llvm_gcov_ctr"))

    // Check if the global is private gcov data.

    if (GV->getName().startswith("__llvm_gcov") ||

        GV->getName().startswith("__llvm_gcda"))

      return false;

  }

llvm/test/Instrumentation/ThreadSanitizer/do-not-instrument-memory-access.ll

+13 −0
Original line number Diff line number Diff line
@@ -13,6 +13,8 @@ target triple = "x86_64-apple-macosx10.9" 


@__llvm_gcov_ctr = internal global [1 x i64] zeroinitializer

@__llvm_gcov_ctr.1 = internal global [1 x i64] zeroinitializer

@__llvm_gcov_global_state_pred = internal global i32 0

@__llvm_gcda_foo = internal global i32 0



define i32 @test_gep() sanitize_thread {

entry:
@@ -42,5 +44,16 @@ entry: 
  ret i32 undef

}



define void @test_load() sanitize_thread {

entry:

  %0 = load i32, i32* @__llvm_gcov_global_state_pred

  store i32 1, i32* @__llvm_gcov_global_state_pred



  %1 = load i32, i32* @__llvm_gcda_foo

  store i32 1, i32* @__llvm_gcda_foo



  ret void

}



; CHECK-NOT: {{call void @__tsan_write}}

; CHECK: __tsan_init