Fix: tracepoint.h should not generate old-style definitions
[lttng-ust.git] / include / lttng / tracepoint.h
index 2753d95a6f7b44c39ac6e71796c8970303248b92..60d8c73b7327bac47dcf4a2053db5aead473615c 100644 (file)
@@ -2,21 +2,33 @@
 #define _LTTNG_TRACEPOINT_H
 
 /*
- * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
- * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ * 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:
  *
- * Permission is hereby granted to use or copy this program
- * for any purpose,  provided the above notices are retained on all copies.
- * Permission to modify the code and to distribute modified code is granted,
- * provided the above notices are retained, and a notice that the code was
- * modified is included with the above copyright notice.
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
  */
 
-#include <urcu-bp.h>
-#include <tracepoint-types.h>
+#include <lttng/tracepoint-types.h>
+#include <lttng/tracepoint-rcu.h>
 #include <urcu/compiler.h>
+#include <dlfcn.h>     /* for dlopen */
+#include <string.h>    /* for memset */
+#include <assert.h>
+#include <lttng/ust-config.h>  /* for sdt */
+
+#ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
+#define SDT_USE_VARIADIC
+#include <sys/sdt.h>
+#else
+#define STAP_PROBEV(...)
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -24,6 +36,7 @@ extern "C" {
 
 #define tracepoint(provider, name, ...)                                            \
        do {                                                                \
+               STAP_PROBEV(provider, name, ## __VA_ARGS__);                \
                if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
                        __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
        } while (0)
@@ -36,8 +49,18 @@ extern "C" {
  * fine too).
  * Each tuple is also separated by a comma.
  */
-#define _TP_COMBINE_TOKENS1(_tokena, _tokenb)       _tokena##_tokenb
-#define _TP_COMBINE_TOKENS(_tokena, _tokenb)        _TP_COMBINE_TOKENS1(_tokena, _tokenb)
+#define __TP_COMBINE_TOKENS(_tokena, _tokenb)                          \
+               _tokena##_tokenb
+#define _TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
+               __TP_COMBINE_TOKENS(_tokena, _tokenb)
+#define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                        \
+               _tokena##_tokenb##_tokenc
+#define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
+               __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
+#define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)       \
+               _tokena##_tokenb##_tokenc##_tokend
+#define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)                \
+               __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
 
 /* _TP_EXVAR* extract the var names. */
 #define _TP_EXVAR0()
@@ -65,7 +88,7 @@ extern "C" {
 #define _TP_EXDATA_VAR20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t)      __tp_data,b,d,f,h,j,l,n,p,r,t
 
 /* _TP_EXPROTO* extract tuples of type, var */
-#define _TP_EXPROTO0()
+#define _TP_EXPROTO0()                                         void
 #define _TP_EXPROTO2(a,b)                                      a b
 #define _TP_EXPROTO4(a,b,c,d)                                  a b,c d
 #define _TP_EXPROTO6(a,b,c,d,e,f)                              a b,c d,e f
@@ -102,14 +125,16 @@ extern "C" {
 #define _TP_ARGS_DATA_VAR(...)         _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 #define _TP_PARAMS(...)                        __VA_ARGS__
 
-#define _DECLARE_TRACEPOINT(provider, name, ...)                                       \
-extern struct tracepoint __tracepoint_##provider##___##name;                           \
-static inline void __tracepoint_cb_##provider##___##name(_TP_ARGS_PROTO(__VA_ARGS__))  \
+#define _DECLARE_TRACEPOINT(_provider, _name, ...)                                     \
+extern struct tracepoint __tracepoint_##_provider##___##_name;                         \
+static inline void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))        \
 {                                                                                      \
        struct tracepoint_probe *__tp_probe;                                            \
                                                                                        \
-       rcu_read_lock_bp();                                                             \
-       __tp_probe = rcu_dereference(__tracepoint_##provider##___##name.probes);        \
+       if (!TP_RCU_LINK_TEST())                                                        \
+               return;                                                                 \
+       tp_rcu_read_lock_bp();                                                          \
+       __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
        if (caa_unlikely(!__tp_probe))                                                  \
                goto end;                                                               \
        do {                                                                            \
@@ -120,40 +145,84 @@ static inline void __tracepoint_cb_##provider##___##name(_TP_ARGS_PROTO(__VA_ARG
                                (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
        } while ((++__tp_probe)->func);                                                 \
 end:                                                                                   \
-       rcu_read_unlock_bp();                                                           \
+       tp_rcu_read_unlock_bp();                                                        \
 }                                                                                      \
-static inline void __tracepoint_register_##provider##___##name(char *name,             \
+static inline void __tracepoint_register_##_provider##___##_name(char *name,           \
                void *func, void *data)                                                 \
 {                                                                                      \
-       __tracepoint_probe_register(name, func, data);                                  \
+       __tracepoint_probe_register(name, func, data,                                   \
+               __tracepoint_##_provider##___##_name.signature);                        \
 }                                                                                      \
-static inline void __tracepoint_unregister_##provider##___##name(char *name,           \
+static inline void __tracepoint_unregister_##_provider##___##_name(char *name,         \
                void *func, void *data)                                                 \
 {                                                                                      \
        __tracepoint_probe_unregister(name, func, data);                                \
 }
 
+extern int __tracepoint_probe_register(const char *name, void *func, void *data,
+               const char *signature);
+extern int __tracepoint_probe_unregister(const char *name, void *func, void *data);
+
+/*
+ * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
+ * shared across objects in a module/main executable.
+ */
+struct tracepoint_dlopen {
+       void *liblttngust_handle;
+
+       int (*tracepoint_register_lib)(struct tracepoint * const *tracepoints_start,
+               int tracepoints_count);
+       int (*tracepoint_unregister_lib)(struct tracepoint * const *tracepoints_start);
+#ifndef _LGPL_SOURCE
+       void (*rcu_read_lock_sym_bp)(void);
+       void (*rcu_read_unlock_sym_bp)(void);
+       void *(*rcu_dereference_sym_bp)(void *p);
+#endif
+};
+
+extern struct tracepoint_dlopen tracepoint_dlopen;
+
+#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)    NULL
+#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)                                     \
-       static const char __tp_strtab_##provider##___##name[]                   \
+#define _TP_EXTRACT_STRING(...)        #__VA_ARGS__
+
+#define _DEFINE_TRACEPOINT(_provider, _name, _args)                            \
+       extern int __tracepoint_provider_##_provider;                           \
+       static const char __tp_strtab_##_provider##___##_name[]                 \
                __attribute__((section("__tracepoints_strings"))) =             \
-                       #provider ":" #name;                                    \
-       struct tracepoint __tracepoint_##provider##___##name                    \
+                       #_provider ":" #_name;                                  \
+       struct tracepoint __tracepoint_##_provider##___##_name                  \
                __attribute__((section("__tracepoints"))) =                     \
-                       { __tp_strtab_##provider##___##name, 0, NULL };         \
-       static struct tracepoint * __tracepoint_ptr_##provider##___##name       \
+               {                                                               \
+                       __tp_strtab_##_provider##___##_name,                    \
+                       0,                                                      \
+                       NULL,                                                   \
+                       _TRACEPOINT_UNDEFINED_REF(_provider),                   \
+                       _TP_EXTRACT_STRING(_args),                              \
+               };                                                              \
+       static struct tracepoint * __tracepoint_ptr_##_provider##___##_name     \
                __attribute__((used, section("__tracepoints_ptrs"))) =          \
-                       &__tracepoint_##provider##___##name;
-
-extern int __tracepoint_probe_register(const char *name, void *func, void *data);
-extern int __tracepoint_probe_unregister(const char *name, void *func, void *data);
-extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
-               int tracepoints_count);
-extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
+                       &__tracepoint_##_provider##___##_name;
 
 /*
  * These weak symbols, the constructor, and destructor take care of
@@ -166,23 +235,66 @@ extern struct tracepoint * const __stop___tracepoints_ptrs[]
        __attribute__((weak, visibility("hidden")));
 int __tracepoint_registered
        __attribute__((weak, visibility("hidden")));
+struct tracepoint_dlopen tracepoint_dlopen
+       __attribute__((weak, visibility("hidden")));
 
 static void __attribute__((constructor)) __tracepoints__init(void)
 {
        if (__tracepoint_registered++)
                return;
-       tracepoint_register_lib(__start___tracepoints_ptrs,
+
+       tracepoint_dlopen.liblttngust_handle =
+               dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
+       if (!tracepoint_dlopen.liblttngust_handle)
+               return;
+       tracepoint_dlopen.tracepoint_register_lib =
+               URCU_FORCE_CAST(int (*)(struct tracepoint * const *, int),
+                               dlsym(tracepoint_dlopen.liblttngust_handle,
+                                       "tracepoint_register_lib"));
+       tracepoint_dlopen.tracepoint_unregister_lib =
+               URCU_FORCE_CAST(int (*)(struct tracepoint * const *),
+                               dlsym(tracepoint_dlopen.liblttngust_handle,
+                                       "tracepoint_unregister_lib"));
+#ifndef _LGPL_SOURCE
+       tracepoint_dlopen.rcu_read_lock_sym_bp =
+               URCU_FORCE_CAST(void (*)(void),
+                               dlsym(tracepoint_dlopen.liblttngust_handle,
+                                       "tp_rcu_read_lock_bp"));
+       tracepoint_dlopen.rcu_read_unlock_sym_bp =
+               URCU_FORCE_CAST(void (*)(void),
+                               dlsym(tracepoint_dlopen.liblttngust_handle,
+                                       "tp_rcu_read_unlock_bp"));
+       tracepoint_dlopen.rcu_dereference_sym_bp =
+               URCU_FORCE_CAST(void *(*)(void *p),
+                               dlsym(tracepoint_dlopen.liblttngust_handle,
+                                       "tp_rcu_dereference_sym_bp"));
+#endif
+       tracepoint_dlopen.tracepoint_register_lib(__start___tracepoints_ptrs,
                                __stop___tracepoints_ptrs -
                                __start___tracepoints_ptrs);
 }
 
 static void __attribute__((destructor)) __tracepoints__destroy(void)
 {
+       int ret;
+
        if (--__tracepoint_registered)
                return;
-       tracepoint_unregister_lib(__start___tracepoints_ptrs);
+       if (tracepoint_dlopen.tracepoint_unregister_lib)
+               tracepoint_dlopen.tracepoint_unregister_lib(__start___tracepoints_ptrs);
+       if (tracepoint_dlopen.liblttngust_handle) {
+               ret = dlclose(tracepoint_dlopen.liblttngust_handle);
+               assert(!ret);
+               memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
+       }
 }
 
+#else /* TRACEPOINT_DEFINE */
+
+#define _DEFINE_TRACEPOINT(_provider, _name, _args)
+
+#endif /* #else TRACEPOINT_DEFINE */
+
 #ifdef __cplusplus
 }
 #endif
@@ -273,68 +385,107 @@ static void __attribute__((destructor)) __tracepoints__destroy(void)
  */
 
 #define TRACEPOINT_EVENT(provider, name, args, fields)                 \
-       _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))
+       _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
+       _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 
 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 
 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)     \
-       _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))
+       _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
+       _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 
 #endif /* #ifndef TRACEPOINT_EVENT */
 
 #ifndef TRACEPOINT_LOGLEVEL
 
 /*
- * Tracepoint Loglevel Declaration Facility
- *
- * This is a place-holder the tracepoint loglevel declaration,
- * overridden by the tracer implementation.
+ * Tracepoint Loglevels
  *
  * Typical use of these loglevels:
  *
- * 1) Declare the mapping between loglevel names and an integer values
- *    within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple.
- *    Do _NOT_ add comma (,) nor semicolon (;) between the
- *    TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor
- *    semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration.  The
- *    name should be a proper C99 identifier.
- *
- *      TRACEPOINT_LOGLEVEL_ENUM(
- *              TP_LOGLEVEL( < loglevel_name >, < value > )
- *              TP_LOGLEVEL( < loglevel_name >, < value > )
- *              ...
- *      )
- *
- *    e.g.:
- *
- *      TRACEPOINT_LOGLEVEL_ENUM(
- *              TP_LOGLEVEL(LOG_EMERG,   0)
- *              TP_LOGLEVEL(LOG_ALERT,   1)
- *              TP_LOGLEVEL(LOG_CRIT,    2)
- *              TP_LOGLEVEL(LOG_ERR,     3)
- *              TP_LOGLEVEL(LOG_WARNING, 4)
- *              TP_LOGLEVEL(LOG_NOTICE,  5)
- *              TP_LOGLEVEL(LOG_INFO,    6)
- *              TP_LOGLEVEL(LOG_DEBUG,   7)
- *      )
- *
- * 2) Then, declare tracepoint loglevels for tracepoints. A
- *    TRACEPOINT_EVENT should be declared prior to the the
- *    TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
- *    is the name of the tracepoint, the second field is the loglevel
- *    name.
+ * The loglevels go from 0 to 14. Higher numbers imply the most
+ * verbosity (higher event throughput expected.
+ *
+ * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
+ * semantic. Loglevels 7 through 13 offer more fine-grained selection of
+ * debug information.
+ *
+ * TRACE_EMERG           0
+ * system is unusable
+ *
+ * TRACE_ALERT           1
+ * action must be taken immediately
+ *
+ * TRACE_CRIT            2
+ * critical conditions
+ *
+ * TRACE_ERR             3
+ * error conditions
+ *
+ * TRACE_WARNING         4
+ * warning conditions
+ *
+ * TRACE_NOTICE          5
+ * normal, but significant, condition
+ *
+ * TRACE_INFO            6
+ * informational message
+ *
+ * TRACE_DEBUG_SYSTEM    7
+ * debug information with system-level scope (set of programs)
+ *
+ * TRACE_DEBUG_PROGRAM   8
+ * debug information with program-level scope (set of processes)
+ *
+ * TRACE_DEBUG_PROCESS   9
+ * debug information with process-level scope (set of modules)
+ *
+ * TRACE_DEBUG_MODULE    10
+ * debug information with module (executable/library) scope (set of units)
+ *
+ * TRACE_DEBUG_UNIT      11
+ * debug information with compilation unit scope (set of functions)
+ *
+ * TRACE_DEBUG_FUNCTION  12
+ * debug information with function-level scope
+ *
+ * TRACE_DEBUG_LINE      13
+ * debug information with line-level scope (TRACEPOINT_EVENT default)
+ *
+ * TRACE_DEBUG           14
+ * 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
+ * tracepoint name. The first field is the provider name, the second
+ * field is the name of the tracepoint, the third field is the loglevel
+ * name.
  *
  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
  *              < loglevel_name >)
  *
- * The TRACEPOINT_PROVIDER must be defined when declaring a
- * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
- * loglevel enumeration apply to the entire TRACEPOINT_PROVIDER. Only one
- * tracepoint loglevel enumeration should be declared per tracepoint
- * provider.
+ * The TRACEPOINT_PROVIDER must be already declared before declaring a
+ * TRACEPOINT_LOGLEVEL.
  */
 
-#define TRACEPOINT_LOGLEVEL_ENUM()
-#define TRACEPOINT_LOGLEVEL(name, loglevel)
+enum {
+       TRACE_EMERG             = 0,
+       TRACE_ALERT             = 1,
+       TRACE_CRIT              = 2,
+       TRACE_ERR               = 3,
+       TRACE_WARNING           = 4,
+       TRACE_NOTICE            = 5,
+       TRACE_INFO              = 6,
+       TRACE_DEBUG_SYSTEM      = 7,
+       TRACE_DEBUG_PROGRAM     = 8,
+       TRACE_DEBUG_PROCESS     = 9,
+       TRACE_DEBUG_MODULE      = 10,
+       TRACE_DEBUG_UNIT        = 11,
+       TRACE_DEBUG_FUNCTION    = 12,
+       TRACE_DEBUG_LINE        = 13,
+       TRACE_DEBUG             = 14,
+};
+
+#define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 
 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
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