Import clang-tsa.h

This defines macros that allow clang to perform Thread Safety Analysis
based on function and variable annotations that specify the locking
rules. On non-clang compilers, the annotations are ignored.

Imported tsa.h from the original repository with the pthread_mutex_t
wrapper removed:

https://github.com/jhi/clang-thread-safety-analysis-for-c.git

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-6-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/qemu/clang-tsa.h

@@ -0,0 +1,101 @@
+#ifndef CLANG_TSA_H
+#define CLANG_TSA_H
+
+/*
+ * Copyright 2018 Jarkko Hietaniemi <jhi@iki.fi>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without
+ * limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/* http://clang.llvm.org/docs/ThreadSafetyAnalysis.html
+ *
+ * TSA is available since clang 3.6-ish.
+ */
+#ifdef __clang__
+#  define TSA(x)   __attribute__((x))
+#else
+#  define TSA(x)   /* No TSA, make TSA attributes no-ops. */
+#endif
+
+/* TSA_CAPABILITY() is used to annotate typedefs:
+ *
+ * typedef pthread_mutex_t TSA_CAPABILITY("mutex") tsa_mutex;
+ */
+#define TSA_CAPABILITY(x) TSA(capability(x))
+
+/* TSA_GUARDED_BY() is used to annotate global variables,
+ * the data is guarded:
+ *
+ * Foo foo TSA_GUARDED_BY(mutex);
+ */
+#define TSA_GUARDED_BY(x) TSA(guarded_by(x))
+
+/* TSA_PT_GUARDED_BY() is used to annotate global pointers, the data
+ * behind the pointer is guarded.
+ *
+ * Foo* ptr TSA_PT_GUARDED_BY(mutex);
+ */
+#define TSA_PT_GUARDED_BY(x) TSA(pt_guarded_by(x))
+
+/* The TSA_REQUIRES() is used to annotate functions: the caller of the
+ * function MUST hold the resource, the function will NOT release it.
+ *
+ * More than one mutex may be specified, comma-separated.
+ *
+ * void Foo(void) TSA_REQUIRES(mutex);
+ */
+#define TSA_REQUIRES(...) TSA(requires_capability(__VA_ARGS__))
+
+/* TSA_EXCLUDES() is used to annotate functions: the caller of the
+ * function MUST NOT hold resource, the function first acquires the
+ * resource, and then releases it.
+ *
+ * More than one mutex may be specified, comma-separated.
+ *
+ * void Foo(void) TSA_EXCLUDES(mutex);
+ */
+#define TSA_EXCLUDES(...) TSA(locks_excluded(__VA_ARGS__))
+
+/* TSA_ACQUIRE() is used to annotate functions: the caller of the
+ * function MUST NOT hold the resource, the function will acquire the
+ * resource, but NOT release it.
+ *
+ * More than one mutex may be specified, comma-separated.
+ *
+ * void Foo(void) TSA_ACQUIRE(mutex);
+ */
+#define TSA_ACQUIRE(...) TSA(acquire_capability(__VA_ARGS__))
+
+/* TSA_RELEASE() is used to annotate functions: the caller of the
+ * function MUST hold the resource, but the function will then release it.
+ *
+ * More than one mutex may be specified, comma-separated.
+ *
+ * void Foo(void) TSA_RELEASE(mutex);
+ */
+#define TSA_RELEASE(...) TSA(release_capability(__VA_ARGS__))
+
+/* TSA_NO_TSA is used to annotate functions.  Use only when you need to.
+ *
+ * void Foo(void) TSA_NO_TSA;
+ */
+#define TSA_NO_TSA TSA(no_thread_safety_analysis)
+
+#endif /* #ifndef CLANG_TSA_H */