Fix: c99: static assert: clang build fails due to multiple typedef
[lttng-ust.git] / include / lttng / ust-compiler.h
index 475caa30ea11131e7bfd607ecc6419708d5e0a23..c0aae11e6c3fb1fe377685f4ea1f3c6cf99131e3 100644 (file)
 
 #include <assert.h>
 
+/*
+ * By default, LTTng-UST uses the priority 150 for the tracepoint and probe
+ * provider constructors to trace tracepoints located within
+ * constructors/destructors with a higher priority value within the same
+ * module. This priority can be overridden by the application.
+ */
+#ifndef LTTNG_UST_CONSTRUCTOR_PRIO
+#define LTTNG_UST_CONSTRUCTOR_PRIO     150
+#endif
+
 #define lttng_ust_notrace __attribute__((no_instrument_function))
 
 /*
  * g++ 4.8 and prior do not support C99 compound literals. Therefore,
  * force allocating those on the heap with these C++ compilers.
  */
-#if defined (__cplusplus) && defined (__GNUC__) && \
-       (__GNUC__ < 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 8))
-# ifndef LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
-#  define LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
+#if defined (__cplusplus) && !defined (__clang__) && defined (__GNUC__) && \
+       ((__GNUC__ < 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 8)))
+# ifndef LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
+#  define LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
 # endif
 #endif
 
  * Compound literals are part of the C99 and C11 standards, but not
  * part of the C++ standards. However, those are supported by both g++ and
  * clang. In order to be strictly C++11 compliant, defining
- * LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header
+ * LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header
  * allocates those on the heap in C++.
  *
  * Example use:
  * static struct mystruct *var = LTTNG_UST_COMPOUND_LITERAL(struct mystruct, { 1, 2, 3 });
  */
-#if defined (__cplusplus) && defined (LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
+#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
 #define LTTNG_UST_COMPOUND_LITERAL(type, ...)  new (type) __VA_ARGS__
 #else
 #define LTTNG_UST_COMPOUND_LITERAL(type, ...)  (type[]) { __VA_ARGS__ }
  *   static assertion. This parameter must be a valid C identifier as it will
  *   be used as a typedef name.
  */
-#if defined (__cplusplus) || __STDC_VERSION__ >= 201112L
+#ifdef __cplusplus
 #define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
        static_assert(predicate, msg)
+#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
+#define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
+       _Static_assert(predicate, msg)
 #else
 /*
  * Evaluates the predicate and emit a compilation error on failure.
  *
- * If the predicate evaluates to true, this macro emits a typedef of an array
- * of size 0.
+ * If the predicate evaluates to true, this macro emits a function
+ * prototype with an argument type which is an array of size 0.
  *
- * If the predicate evaluates to false, this macro emits a typedef of an array
- * of negative size which is invalid in C and forces a compiler error. The msg
- * parameter is used in the tentative typedef so it is printed to the user.
+ * If the predicate evaluates to false, this macro emits a function
+ * prototype with an argument type which is an array of negative size
+ * which is invalid in C and forces a compiler error. The
+ * c_identifier_msg parameter is used as the argument identifier so it
+ * is printed to the user when the error is reported.
  */
 #define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
-    typedef char lttng_ust_static_assert_##c_identifier_msg[2*!!(predicate)-1]
+       void lttng_ust_static_assert_proto(char c_identifier_msg[2*!!(predicate)-1])
+#endif
+
+/* Combine two tokens. */
+#define LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)                   \
+               _tokena##_tokenb
+#define LTTNG_UST_COMPILER_COMBINE_TOKENS(_tokena, _tokenb)                    \
+               LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)
+/*
+ * Wrap constructor and destructor functions to invoke them as functions with
+ * the constructor/destructor GNU C attributes, which ensures that those
+ * constructors/destructors are ordered before/after C++
+ * constructors/destructors.
+ *
+ * Wrap constructor and destructor functions as the constructor/destructor of a
+ * variable defined within an anonymous namespace when building as C++ with
+ * LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP defined. With this option,
+ * there are no guarantees that the events in C++ constructors/destructors will
+ * be traced.
+ */
+#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
+#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,       \
+                                                destructor_func, ...)          \
+namespace lttng {                                                              \
+namespace ust {                                                                        \
+namespace details {                                                            \
+class LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_,      \
+                                  name) {                                      \
+public:                                                                                \
+       LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
+       ~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
+};                                                                             \
+LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
+{                                                                              \
+       constructor_func();                                                     \
+}                                                                              \
+LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
+{                                                                              \
+       destructor_func();                                                      \
+}                                                                              \
+}                                                                              \
+}                                                                              \
+}                                                                              \
+                                                                               \
+namespace {                                                                    \
+const lttng::ust::details::LTTNG_UST_COMPILER_COMBINE_TOKENS(                  \
+       lttng_ust_constructor_destructor_, name)                                \
+               LTTNG_UST_COMPILER_COMBINE_TOKENS(name, registration_instance); \
+}
+#else
+#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,       \
+                                                destructor_func, ...)          \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
+               __attribute__((constructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
+       {                                                                       \
+               constructor_func();                                             \
+       }                                                                       \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
+               __attribute__((destructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
+       {                                                                       \
+               destructor_func();                                              \
+       }
 #endif
 
 #endif /* _LTTNG_UST_COMPILER_H */
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