Commit 129456fe2e9cc1b77e0f52784a0e73030ee8cf1b
2014-02-07T11:52:35
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!
diff --git a/include/SDL_assert.h b/include/SDL_assert.h
index 4441dbf..57a4f86 100644
--- a/include/SDL_assert.h
+++ b/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();