@matheusbsbs / matheus-bagliano / commits / c112084af9

fast-export: avoid NULL pointer arithmetic

Clang 6 reports the following warning, which is turned into an error in a DEVELOPER build: builtin/fast-export.c:162:28: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] return ((uint32_t *)NULL) + mark; ~~~~~~~~~~~~~~~~~~ ^ 1 error generated. The compiler is correct, and the error message speaks for itself. There is no need for any undefined operation -- just cast mark to void * or uint32_t after an intermediate cast to uintptr_t. That encodes the integer value into a pointer and later decodes it as intended. While at it remove an outdated comment -- intptr_t has been used since ffe659f94d (parse-options: make some arguments optional, add callbacks), committed in October 2007. Signed-off-by: Rene Scharfe <l.s.r@web.de> Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed May 9, 2018 at 23:06 UTC c112084af965ade0836b7c226c68ecd8b536fc0a

1 file changed +3 -4

builtin/fast-export.c

+3 -4

@@ -154,15 +154,14 @@ static void anonymize_path(struct strbuf *out, const char *path,

154 }

155 }

156

157 -/* Since intptr_t is C99, we do not use it here */

158 -static inline uint32_t *mark_to_ptr(uint32_t mark)

157 +static inline void *mark_to_ptr(uint32_t mark)

158 {

160 - return ((uint32_t *)NULL) + mark;

159 + return (void *)(uintptr_t)mark;

160 }

161

162 static inline uint32_t ptr_to_mark(void * mark)

163 {

165 - return (uint32_t *)mark - (uint32_t *)NULL;

164 + return (uint32_t)(uintptr_t)mark;

165 }

166

167 static inline void mark_object(struct object *object, uint32_t mark)