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Tell Clang's static analysis that SDL_assert() is an assertion handler.

This lets it know, for example, that when you do this...

    SDL_assert(ptr != NULL);

...that (ptr) is definitely not NULL at this point in the program, for the
sake of static analysis. While a buggy program could definitely trigger this
assertion, Clang assumes your assertion check is covering it and won't
report possible NULL dereferences after this point.

Since SDL_assert might continue if the user clicks "ignore", without this
change Clang would notice you checked for NULL (meaning that NULL is a real
possibility here) and still wrote code outside of that test branch that
dereferences the pointer, and thus would always trigger false positives.

Static analysis is fun!
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icculus committed Feb 7, 2014
1 parent d3f6421 commit 129456fe2e9cc1b77e0f52784a0e73030ee8cf1b
Showing with 8 additions and 1 deletion.
  1. +8 −1 include/SDL_assert.h
@@ -120,7 +120,14 @@ typedef struct SDL_assert_data
/* Never call this directly. Use the SDL_assert* macros. */
extern DECLSPEC SDL_assert_state SDLCALL SDL_ReportAssertion(SDL_assert_data *,
const char *,
const char *, int);
const char *, int)
#if defined(__clang__) && __has_feature(attribute_analyzer_noreturn)
/* this tells Clang's static analysis that we're a custom assert function,
and that the analyzer should assume the condition was always true past this
SDL_assert test. */
__attribute__((analyzer_noreturn))
#endif
;

/* the do {} while(0) avoids dangling else problems:
if (x) SDL_assert(y); else blah();

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