Fix static provider linking: introduce TRACEPOINT_PROBE_DYNAMIC_LINKAGE

[lttng-ust.git] / include / lttng / tracepoint.h

diff --git a/include/lttng/tracepoint.h b/include/lttng/tracepoint.h
index 9f36d39a65cd676143a773e54edabb43204cf0f3..887c9deea87b4653d944f8b9658b454d380de8bb 100644 (file)
--- a/include/lttng/tracepoint.h
+++ b/include/lttng/tracepoint.h
@@ -152,18 +152,35 @@ extern int __tracepoint_probe_unregister(const char *name, void *func, void *dat
 
 #ifdef TRACEPOINT_DEFINE
 
+/*
+ * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
+ * unresolved symbol that requires the provider to be linked in. When
+ * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
+ * unresolved symbol that depends on having the provider linked in,
+ * otherwise the linker complains. This deals with use of static
+ * libraries, ensuring that the linker does not remove the provider
+ * object from the executable.
+ */
+#ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
+#define _TRACEPOINT_UNDEFINED_REF(provider)
+#else  /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
+#define _TRACEPOINT_UNDEFINED_REF(provider)    \
+       &__tracepoint_provider_##provider,
+#endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
+
 /*
  * Note: to allow PIC code, we need to allow the linker to update the pointers
  * in the __tracepoints_ptrs section.
  * Therefore, this section is _not_ const (read-only).
  */
 #define _DEFINE_TRACEPOINT(provider, name)                                     \
+       extern int __tracepoint_provider_##provider;                            \
        static const char __tp_strtab_##provider##___##name[]                   \
                __attribute__((section("__tracepoints_strings"))) =             \
                        #provider ":" #name;                                    \
        struct tracepoint __tracepoint_##provider##___##name                    \
                __attribute__((section("__tracepoints"))) =                     \
-                       { __tp_strtab_##provider##___##name, 0, NULL };         \
+                       { __tp_strtab_##provider##___##name, 0, NULL, _TRACEPOINT_UNDEFINED_REF(provider) };            \
        static struct tracepoint * __tracepoint_ptr_##provider##___##name       \
                __attribute__((used, section("__tracepoints_ptrs"))) =          \
                        &__tracepoint_##provider##___##name;
@@ -377,32 +394,32 @@ static void __attribute__((destructor)) __tracepoints__destroy(void)
  * TRACE_INFO     6
  * informational message
  *
- * TRACE_DEBUG_SYSTEM   7
- * information has system-level scope
+ * TRACE_SYSTEM   7
+ * information has system-level scope (set of programs)
  *
- * TRACE_PROCESS  8
- * information has process-level scope
+ * TRACE_PROGRAM  8
+ * information has program-level scope (set of processes)
  *
- * TRACE_MODULE   9
- * information has module (executable/library) scope
+ * TRACE_PROCESS  9
+ * information has process-level scope (set of modules)
  *
- * TRACE_UNIT     10
- * information has compilation unit scope
+ * TRACE_MODULE   10
+ * information has module (executable/library) scope (set of units)
  *
- * TRACE_CLASS    11
- * information has class-level scope
+ * TRACE_UNIT     11
+ * information has compilation unit scope (set of functions)
  *
- * TRACE_OBJECT   12
- * information has object-level scope
- *
- * TRACE_FUNCTION 13
+ * TRACE_FUNCTION 12
  * information has function-level scope
  *
- * TRACE_PRINTF   14
- * tracepoint_printf message
+ * TRACE_DEFAULT  13
+ * default trace loglevel (TRACEPOINT_EVENT default)
+ *
+ * TRACE_VERBOSE  14
+ * verbose information
  *
  * TRACE_DEBUG    15
- * debug-level message
+ * debug-level message (trace_printf default)
  *
  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
@@ -416,7 +433,25 @@ static void __attribute__((destructor)) __tracepoints__destroy(void)
  * TRACEPOINT_LOGLEVEL.
  */
 
-#define TRACEPOINT_LOGLEVEL_ENUM(...)
+enum {
+       TRACE_EMERG     = 0,
+       TRACE_ALERT     = 1,
+       TRACE_CRIT      = 2,
+       TRACE_ERR       = 3,
+       TRACE_WARNING   = 4,
+       TRACE_NOTICE    = 5,
+       TRACE_INFO      = 6,
+       TRACE_SYSTEM    = 7,
+       TRACE_PROGRAM   = 8,
+       TRACE_PROCESS   = 9,
+       TRACE_MODULE    = 10,
+       TRACE_UNIT      = 11,
+       TRACE_FUNCTION  = 12,
+       TRACE_DEFAULT   = 13,
+       TRACE_VERBOSE   = 14,
+       TRACE_DEBUG     = 15,
+};
+
 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 
 #endif /* #ifndef TRACEPOINT_LOGLEVEL */