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-rw-r--r--include/llvm/Support/ManagedStatic.h5
-rw-r--r--include/llvm/Support/Valgrind.h45
-rw-r--r--lib/Support/ManagedStatic.cpp8
-rw-r--r--lib/Support/Valgrind.cpp11
-rw-r--r--unittests/Support/ManagedStatic.cpp39
5 files changed, 107 insertions, 1 deletions
diff --git a/include/llvm/Support/ManagedStatic.h b/include/llvm/Support/ManagedStatic.h
index 53e73ad..4171d1b 100644
--- a/include/llvm/Support/ManagedStatic.h
+++ b/include/llvm/Support/ManagedStatic.h
@@ -16,6 +16,7 @@
#include "llvm/Support/Atomic.h"
#include "llvm/Support/Threading.h"
+#include "llvm/Support/Valgrind.h"
namespace llvm {
@@ -65,6 +66,7 @@ public:
void* tmp = Ptr;
if (llvm_is_multithreaded()) sys::MemoryFence();
if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
+ TsanHappensAfter(this);
return *static_cast<C*>(Ptr);
}
@@ -72,6 +74,7 @@ public:
void* tmp = Ptr;
if (llvm_is_multithreaded()) sys::MemoryFence();
if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
+ TsanHappensAfter(this);
return static_cast<C*>(Ptr);
}
@@ -79,6 +82,7 @@ public:
void* tmp = Ptr;
if (llvm_is_multithreaded()) sys::MemoryFence();
if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
+ TsanHappensAfter(this);
return *static_cast<C*>(Ptr);
}
@@ -86,6 +90,7 @@ public:
void* tmp = Ptr;
if (llvm_is_multithreaded()) sys::MemoryFence();
if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call);
+ TsanHappensAfter(this);
return static_cast<C*>(Ptr);
}
diff --git a/include/llvm/Support/Valgrind.h b/include/llvm/Support/Valgrind.h
index 7662eaa..0ecd33b 100644
--- a/include/llvm/Support/Valgrind.h
+++ b/include/llvm/Support/Valgrind.h
@@ -16,8 +16,25 @@
#ifndef LLVM_SYSTEM_VALGRIND_H
#define LLVM_SYSTEM_VALGRIND_H
+#include "llvm/Support/Compiler.h"
+#include "llvm/Config/config.h"
#include <stddef.h>
+#if ENABLE_THREADS != 0 && !defined(NDEBUG)
+// tsan (Thread Sanitizer) is a valgrind-based tool that detects these exact
+// functions by name.
+extern "C" {
+LLVM_ATTRIBUTE_NOINLINE void AnnotateHappensAfter(const char *file, int line,
+ const volatile void *cv);
+LLVM_ATTRIBUTE_NOINLINE void AnnotateHappensBefore(const char *file, int line,
+ const volatile void *cv);
+LLVM_ATTRIBUTE_NOINLINE void AnnotateIgnoreWritesBegin(const char *file,
+ int line);
+LLVM_ATTRIBUTE_NOINLINE void AnnotateIgnoreWritesEnd(const char *file,
+ int line);
+}
+#endif
+
namespace llvm {
namespace sys {
// True if Valgrind is controlling this process.
@@ -26,6 +43,34 @@ namespace sys {
// Discard valgrind's translation of code in the range [Addr .. Addr + Len).
// Otherwise valgrind may continue to execute the old version of the code.
void ValgrindDiscardTranslations(const void *Addr, size_t Len);
+
+#if ENABLE_THREADS != 0 && !defined(NDEBUG)
+ // Thread Sanitizer is a valgrind tool that finds races in code.
+ // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
+
+ // This marker is used to define a happens-before arc. The race detector will
+ // infer an arc from the begin to the end when they share the same pointer
+ // argument.
+ #define TsanHappensBefore(cv) \
+ AnnotateHappensBefore(__FILE__, __LINE__, cv)
+
+ // This marker defines the destination of a happens-before arc.
+ #define TsanHappensAfter(cv) \
+ AnnotateHappensAfter(__FILE__, __LINE__, cv)
+
+ // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
+ #define TsanIgnoreWritesBegin() \
+ AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
+
+ // Resume checking for racy writes.
+ #define TsanIgnoreWritesEnd() \
+ AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
+#else
+ #define TsanHappensBefore(cv)
+ #define TsanHappensAfter(cv)
+ #define TsanIgnoreWritesBegin()
+ #define TsanIgnoreWritesEnd()
+#endif
}
}
diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp
index c767c15..098cccb 100644
--- a/lib/Support/ManagedStatic.cpp
+++ b/lib/Support/ManagedStatic.cpp
@@ -27,8 +27,15 @@ void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
if (Ptr == 0) {
void* tmp = Creator ? Creator() : 0;
+ TsanHappensBefore(this);
sys::MemoryFence();
+
+ // This write is racy against the first read in the ManagedStatic
+ // accessors. The race is benign because it does a second read after a
+ // memory fence, at which point it isn't possible to get a partial value.
+ TsanIgnoreWritesBegin();
Ptr = tmp;
+ TsanIgnoreWritesEnd();
DeleterFn = Deleter;
// Add to list of managed statics.
@@ -72,4 +79,3 @@ void llvm::llvm_shutdown() {
if (llvm_is_multithreaded()) llvm_stop_multithreaded();
}
-
diff --git a/lib/Support/Valgrind.cpp b/lib/Support/Valgrind.cpp
index 7034485..078d705 100644
--- a/lib/Support/Valgrind.cpp
+++ b/lib/Support/Valgrind.cpp
@@ -52,3 +52,14 @@ void llvm::sys::ValgrindDiscardTranslations(const void *Addr, size_t Len) {
}
#endif // !HAVE_VALGRIND_VALGRIND_H
+
+// These functions require no implementation, tsan just looks at the arguments
+// they're called with.
+extern "C" {
+void AnnotateHappensBefore(const char *file, int line,
+ const volatile void *cv) {}
+void AnnotateHappensAfter(const char *file, int line,
+ const volatile void *cv) {}
+void AnnotateIgnoreWritesBegin(const char *file, int line) {}
+void AnnotateIgnoreWritesEnd(const char *file, int line) {}
+}
diff --git a/unittests/Support/ManagedStatic.cpp b/unittests/Support/ManagedStatic.cpp
new file mode 100644
index 0000000..f1f0320
--- /dev/null
+++ b/unittests/Support/ManagedStatic.cpp
@@ -0,0 +1,39 @@
+//===- llvm/unittest/Support/ManagedStatic.cpp - ManagedStatic tests ------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Threading.h"
+#include <pthread.h>
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+namespace test1 {
+ llvm::ManagedStatic<int> ms;
+ void *helper(void*) {
+ *ms;
+ return NULL;
+ }
+}
+
+TEST(Initialize, MultipleThreads) {
+ // Run this test under tsan: http://code.google.com/p/data-race-test/
+
+ llvm_start_multithreaded();
+ pthread_t t1, t2;
+ pthread_create(&t1, NULL, test1::helper, NULL);
+ pthread_create(&t2, NULL, test1::helper, NULL);
+ pthread_join(t1, NULL);
+ pthread_join(t2, NULL);
+ llvm_stop_multithreaded();
+}
+
+} // anonymous namespace
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