macros: Add thread-safety annotation macros

Extracted from !7529

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9061>

meson.build

@@ -1040,6 +1040,7 @@ else
     '-Werror=incompatible-pointer-types',
     '-Werror=int-conversion',
     '-Wimplicit-fallthrough',
+    '-Werror=thread-safety',
     '-Wno-missing-field-initializers',
     '-Wno-format-truncation',
     '-fno-math-errno',

src/util/macros.h

@@ -40,6 +40,10 @@
 #  define __has_builtin(x) 0
 #endif
 
+#ifndef __has_attribute
+#  define __has_attribute(x) 0
+#endif
+
 /**
  * __builtin_expect macros
  */
@@ -412,4 +416,32 @@ enum pipe_debug_type
 #endif
 #endif
 
+/* Macros for static type-safety checking.
+ *
+ * https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
+ */
+
+#if __has_attribute(capability)
+typedef int __attribute__((capability("mutex"))) lock_cap_t;
+
+#define guarded_by(l) __attribute__((guarded_by(l)))
+#define acquire_cap(l) __attribute((acquire_capability(l), no_thread_safety_analysis))
+#define release_cap(l) __attribute((release_capability(l), no_thread_safety_analysis))
+#define assert_cap(l) __attribute((assert_capability(l), no_thread_safety_analysis))
+#define requires_cap(l) __attribute((requires_capability(l)))
+#define disable_thread_safety_analysis __attribute((no_thread_safety_analysis))
+
+#else
+
+typedef int lock_cap_t;
+
+#define guarded_by(l)
+#define acquire_cap(l)
+#define release_cap(l)
+#define assert_cap(l)
+#define requires_cap(l)
+#define disable_thread_safety_analysis
+
+#endif
+
 #endif /* UTIL_MACROS_H */