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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!
This commit is contained in:
Ryan C. Gordon 2014-02-07 11:52:35 -05:00
parent d3f64213e2
commit 129456fe2e
1 changed files with 8 additions and 1 deletions
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9
include/SDL_assert.h
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@ -120,7 +120,14 @@ typedef struct SDL_assert_data
/* Never call this directly. Use the SDL_assert* macros. */ /* Never call this directly. Use the SDL_assert* macros. */
extern DECLSPEC SDL_assert_state SDLCALL SDL_ReportAssertion(SDL_assert_data *, extern DECLSPEC SDL_assert_state SDLCALL SDL_ReportAssertion(SDL_assert_data *,
const char *, 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: /* the do {} while(0) avoids dangling else problems:
if (x) SDL_assert(y); else blah(); if (x) SDL_assert(y); else blah();