include/qemu: Added tsan.h for annotations.

These annotations will allow us to give tsan
additional hints.  For example, we can inform
tsan about reads/writes to ignore to silence certain
classes of warnings.
We can also annotate threads so that the proper thread
naming shows up in tsan warning results.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200609200738.445-11-robert.foley@linaro.org>
Message-Id: <20200612190237.30436-14-alex.bennee@linaro.org>

include/qemu/tsan.h

@@ -0,0 +1,71 @@
+#ifndef QEMU_TSAN_H
+#define QEMU_TSAN_H
+/*
+ * tsan.h
+ *
+ * This file defines macros used to give ThreadSanitizer
+ * additional information to help suppress warnings.
+ * This is necessary since TSan does not provide a header file
+ * for these annotations.  The standard way to include these
+ * is via the below macros.
+ *
+ * Annotation examples can be found here:
+ *  https://github.com/llvm/llvm-project/tree/master/compiler-rt/test/tsan
+ * annotate_happens_before.cpp or ignore_race.cpp are good places to start.
+ *
+ * The full set of annotations can be found here in tsan_interface_ann.cpp.
+ *  https://github.com/llvm/llvm-project/blob/master/compiler-rt/lib/tsan/rtl/
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifdef CONFIG_TSAN
+/*
+ * Informs TSan of a happens before/after relationship.
+ */
+#define QEMU_TSAN_ANNOTATE_HAPPENS_BEFORE(addr) \
+    AnnotateHappensBefore(__FILE__, __LINE__, (void *)(addr))
+#define QEMU_TSAN_ANNOTATE_HAPPENS_AFTER(addr) \
+    AnnotateHappensAfter(__FILE__, __LINE__, (void *)(addr))
+/*
+ * Gives TSan more information about thread names it can report the
+ * name of the thread in the warning report.
+ */
+#define QEMU_TSAN_ANNOTATE_THREAD_NAME(name) \
+    AnnotateThreadName(__FILE__, __LINE__, (void *)(name))
+/*
+ * Allows defining a region of code on which TSan will not record memory READS.
+ * This has the effect of disabling race detection for this section of code.
+ */
+#define QEMU_TSAN_ANNOTATE_IGNORE_READS_BEGIN() \
+    AnnotateIgnoreReadsBegin(__FILE__, __LINE__)
+#define QEMU_TSAN_ANNOTATE_IGNORE_READS_END() \
+    AnnotateIgnoreReadsEnd(__FILE__, __LINE__)
+/*
+ * Allows defining a region of code on which TSan will not record memory
+ * WRITES.  This has the effect of disabling race detection for this
+ * section of code.
+ */
+#define QEMU_TSAN_ANNOTATE_IGNORE_WRITES_BEGIN() \
+    AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
+#define QEMU_TSAN_ANNOTATE_IGNORE_WRITES_END() \
+    AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
+#else
+#define QEMU_TSAN_ANNOTATE_HAPPENS_BEFORE(addr)
+#define QEMU_TSAN_ANNOTATE_HAPPENS_AFTER(addr)
+#define QEMU_TSAN_ANNOTATE_THREAD_NAME(name)
+#define QEMU_TSAN_ANNOTATE_IGNORE_READS_BEGIN()
+#define QEMU_TSAN_ANNOTATE_IGNORE_READS_END()
+#define QEMU_TSAN_ANNOTATE_IGNORE_WRITES_BEGIN()
+#define QEMU_TSAN_ANNOTATE_IGNORE_WRITES_END()
+#endif
+
+void AnnotateHappensBefore(const char *f, int l, void *addr);
+void AnnotateHappensAfter(const char *f, int l, void *addr);
+void AnnotateThreadName(const char *f, int l, char *name);
+void AnnotateIgnoreReadsBegin(const char *f, int l);
+void AnnotateIgnoreReadsEnd(const char *f, int l);
+void AnnotateIgnoreWritesBegin(const char *f, int l);
+void AnnotateIgnoreWritesEnd(const char *f, int l);
+#endif