include/SDL_assert.h
author Sam Lantinga <slouken@libsdl.org>
Tue, 15 Nov 2016 01:30:08 -0800
changeset 10616 d17dd08640a4
parent 9998 f67cf37e9cd4
child 10636 e692b9291c81
permissions -rw-r--r--
Fixed bug 1646 - Warnings from clang with -Weverything
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 #ifndef _SDL_assert_h
    23 #define _SDL_assert_h
    24 
    25 #include "SDL_config.h"
    26 
    27 #include "begin_code.h"
    28 /* Set up for C function definitions, even when using C++ */
    29 #ifdef __cplusplus
    30 extern "C" {
    31 #endif
    32 
    33 #ifndef SDL_ASSERT_LEVEL
    34 #ifdef SDL_DEFAULT_ASSERT_LEVEL
    35 #define SDL_ASSERT_LEVEL SDL_DEFAULT_ASSERT_LEVEL
    36 #elif defined(_DEBUG) || defined(DEBUG) || \
    37       (defined(__GNUC__) && !defined(__OPTIMIZE__))
    38 #define SDL_ASSERT_LEVEL 2
    39 #else
    40 #define SDL_ASSERT_LEVEL 1
    41 #endif
    42 #endif /* SDL_ASSERT_LEVEL */
    43 
    44 /*
    45 These are macros and not first class functions so that the debugger breaks
    46 on the assertion line and not in some random guts of SDL, and so each
    47 assert can have unique static variables associated with it.
    48 */
    49 
    50 #if defined(_MSC_VER)
    51 /* Don't include intrin.h here because it contains C++ code */
    52     extern void __cdecl __debugbreak(void);
    53     #define SDL_TriggerBreakpoint() __debugbreak()
    54 #elif (!defined(__NACL__) && defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
    55     #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
    56 #elif defined(HAVE_SIGNAL_H)
    57     #include <signal.h>
    58     #define SDL_TriggerBreakpoint() raise(SIGTRAP)
    59 #else
    60     /* How do we trigger breakpoints on this platform? */
    61     #define SDL_TriggerBreakpoint()
    62 #endif
    63 
    64 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
    65 #   define SDL_FUNCTION __func__
    66 #elif ((__GNUC__ >= 2) || defined(_MSC_VER))
    67 #   define SDL_FUNCTION __FUNCTION__
    68 #else
    69 #   define SDL_FUNCTION "???"
    70 #endif
    71 #define SDL_FILE    __FILE__
    72 #define SDL_LINE    __LINE__
    73 
    74 /*
    75 sizeof (x) makes the compiler still parse the expression even without
    76 assertions enabled, so the code is always checked at compile time, but
    77 doesn't actually generate code for it, so there are no side effects or
    78 expensive checks at run time, just the constant size of what x WOULD be,
    79 which presumably gets optimized out as unused.
    80 This also solves the problem of...
    81 
    82     int somevalue = blah();
    83     SDL_assert(somevalue == 1);
    84 
    85 ...which would cause compiles to complain that somevalue is unused if we
    86 disable assertions.
    87 */
    88 
    89 /* "while (0,0)" fools Microsoft's compiler's /W4 warning level into thinking
    90     this condition isn't constant. And looks like an owl's face! */
    91 #ifdef _MSC_VER  /* stupid /W4 warnings. */
    92 #define SDL_NULL_WHILE_LOOP_CONDITION (0,0)
    93 #else
    94 #define SDL_NULL_WHILE_LOOP_CONDITION (0)
    95 #endif
    96 
    97 #define SDL_disabled_assert(condition) \
    98     do { (void) sizeof ((condition)); } while (SDL_NULL_WHILE_LOOP_CONDITION)
    99 
   100 typedef enum
   101 {
   102     SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
   103     SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
   104     SDL_ASSERTION_ABORT,  /**< Terminate the program. */
   105     SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
   106     SDL_ASSERTION_ALWAYS_IGNORE  /**< Ignore the assert from now on. */
   107 } SDL_AssertState;
   108 
   109 typedef struct SDL_AssertData
   110 {
   111     int always_ignore;
   112     unsigned int trigger_count;
   113     const char *condition;
   114     const char *filename;
   115     int linenum;
   116     const char *function;
   117     const struct SDL_AssertData *next;
   118 } SDL_AssertData;
   119 
   120 #if (SDL_ASSERT_LEVEL > 0)
   121 
   122 /* Never call this directly. Use the SDL_assert* macros. */
   123 extern DECLSPEC SDL_AssertState SDLCALL SDL_ReportAssertion(SDL_AssertData *,
   124                                                              const char *,
   125                                                              const char *, int)
   126 #if defined(__clang__)
   127 #if __has_feature(attribute_analyzer_noreturn)
   128 /* this tells Clang's static analysis that we're a custom assert function,
   129    and that the analyzer should assume the condition was always true past this
   130    SDL_assert test. */
   131    __attribute__((analyzer_noreturn))
   132 #endif
   133 #endif
   134 ;
   135 
   136 /* the do {} while(0) avoids dangling else problems:
   137     if (x) SDL_assert(y); else blah();
   138        ... without the do/while, the "else" could attach to this macro's "if".
   139    We try to handle just the minimum we need here in a macro...the loop,
   140    the static vars, and break points. The heavy lifting is handled in
   141    SDL_ReportAssertion(), in SDL_assert.c.
   142 */
   143 #define SDL_enabled_assert(condition) \
   144     do { \
   145         while ( !(condition) ) { \
   146             static struct SDL_AssertData sdl_assert_data = { \
   147                 0, 0, #condition, 0, 0, 0, 0 \
   148             }; \
   149             const SDL_AssertState sdl_assert_state = SDL_ReportAssertion(&sdl_assert_data, SDL_FUNCTION, SDL_FILE, SDL_LINE); \
   150             if (sdl_assert_state == SDL_ASSERTION_RETRY) { \
   151                 continue; /* go again. */ \
   152             } else if (sdl_assert_state == SDL_ASSERTION_BREAK) { \
   153                 SDL_TriggerBreakpoint(); \
   154             } \
   155             break; /* not retrying. */ \
   156         } \
   157     } while (SDL_NULL_WHILE_LOOP_CONDITION)
   158 
   159 #endif  /* enabled assertions support code */
   160 
   161 /* Enable various levels of assertions. */
   162 #if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
   163 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   164 #   define SDL_assert_release(condition) SDL_disabled_assert(condition)
   165 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   166 #elif SDL_ASSERT_LEVEL == 1  /* release settings. */
   167 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   168 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   169 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   170 #elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
   171 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   172 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   173 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   174 #elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
   175 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   176 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   177 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
   178 #else
   179 #   error Unknown assertion level.
   180 #endif
   181 
   182 /* this assertion is never disabled at any level. */
   183 #define SDL_assert_always(condition) SDL_enabled_assert(condition)
   184 
   185 
   186 typedef SDL_AssertState (SDLCALL *SDL_AssertionHandler)(
   187                                  const SDL_AssertData* data, void* userdata);
   188 
   189 /**
   190  *  \brief Set an application-defined assertion handler.
   191  *
   192  *  This allows an app to show its own assertion UI and/or force the
   193  *  response to an assertion failure. If the app doesn't provide this, SDL
   194  *  will try to do the right thing, popping up a system-specific GUI dialog,
   195  *  and probably minimizing any fullscreen windows.
   196  *
   197  *  This callback may fire from any thread, but it runs wrapped in a mutex, so
   198  *  it will only fire from one thread at a time.
   199  *
   200  *  Setting the callback to NULL restores SDL's original internal handler.
   201  *
   202  *  This callback is NOT reset to SDL's internal handler upon SDL_Quit()!
   203  *
   204  *  \return SDL_AssertState value of how to handle the assertion failure.
   205  *
   206  *  \param handler Callback function, called when an assertion fails.
   207  *  \param userdata A pointer passed to the callback as-is.
   208  */
   209 extern DECLSPEC void SDLCALL SDL_SetAssertionHandler(
   210                                             SDL_AssertionHandler handler,
   211                                             void *userdata);
   212 
   213 /**
   214  *  \brief Get the default assertion handler.
   215  *
   216  *  This returns the function pointer that is called by default when an
   217  *   assertion is triggered. This is an internal function provided by SDL,
   218  *   that is used for assertions when SDL_SetAssertionHandler() hasn't been
   219  *   used to provide a different function.
   220  *
   221  *  \return The default SDL_AssertionHandler that is called when an assert triggers.
   222  */
   223 extern DECLSPEC SDL_AssertionHandler SDLCALL SDL_GetDefaultAssertionHandler(void);
   224 
   225 /**
   226  *  \brief Get the current assertion handler.
   227  *
   228  *  This returns the function pointer that is called when an assertion is
   229  *   triggered. This is either the value last passed to
   230  *   SDL_SetAssertionHandler(), or if no application-specified function is
   231  *   set, is equivalent to calling SDL_GetDefaultAssertionHandler().
   232  *
   233  *   \param puserdata Pointer to a void*, which will store the "userdata"
   234  *                    pointer that was passed to SDL_SetAssertionHandler().
   235  *                    This value will always be NULL for the default handler.
   236  *                    If you don't care about this data, it is safe to pass
   237  *                    a NULL pointer to this function to ignore it.
   238  *  \return The SDL_AssertionHandler that is called when an assert triggers.
   239  */
   240 extern DECLSPEC SDL_AssertionHandler SDLCALL SDL_GetAssertionHandler(void **puserdata);
   241 
   242 /**
   243  *  \brief Get a list of all assertion failures.
   244  *
   245  *  Get all assertions triggered since last call to SDL_ResetAssertionReport(),
   246  *  or the start of the program.
   247  *
   248  *  The proper way to examine this data looks something like this:
   249  *
   250  *  <code>
   251  *  const SDL_AssertData *item = SDL_GetAssertionReport();
   252  *  while (item) {
   253  *      printf("'%s', %s (%s:%d), triggered %u times, always ignore: %s.\n",
   254  *             item->condition, item->function, item->filename,
   255  *             item->linenum, item->trigger_count,
   256  *             item->always_ignore ? "yes" : "no");
   257  *      item = item->next;
   258  *  }
   259  *  </code>
   260  *
   261  *  \return List of all assertions.
   262  *  \sa SDL_ResetAssertionReport
   263  */
   264 extern DECLSPEC const SDL_AssertData * SDLCALL SDL_GetAssertionReport(void);
   265 
   266 /**
   267  *  \brief Reset the list of all assertion failures.
   268  *
   269  *  Reset list of all assertions triggered.
   270  *
   271  *  \sa SDL_GetAssertionReport
   272  */
   273 extern DECLSPEC void SDLCALL SDL_ResetAssertionReport(void);
   274 
   275 
   276 /* these had wrong naming conventions until 2.0.4. Please update your app! */
   277 #define SDL_assert_state SDL_AssertState
   278 #define SDL_assert_data SDL_AssertData
   279 
   280 
   281 /* Ends C function definitions when using C++ */
   282 #ifdef __cplusplus
   283 }
   284 #endif
   285 #include "close_code.h"
   286 
   287 #endif /* _SDL_assert_h */
   288 
   289 /* vi: set ts=4 sw=4 expandtab: */