Make tor_free only evaluate its input once (at least on gcc and clang)

2024-12-06 19:41:15 +01:00 · 2017-12-04 15:18:13 -05:00
parent db024adc90
commit 1d348989b0
2 changed files with 10 additions and 1 deletions
@@ -80,12 +80,22 @@ extern int dmalloc_free(const char *file, const int line, void *pnt,
 * This is a macro.  If you need a function pointer to release memory from
 * tor_malloc(), use tor_free_().
 */
+#ifdef __GNUC__
+#define tor_free(p) STMT_BEGIN                                 \
+    typeof(&(p)) tor_free__tmpvar = &(p);                      \
+    if (PREDICT_LIKELY((*tor_free__tmpvar)!=NULL)) {           \
+      raw_free(*tor_free__tmpvar);                             \
+      *tor_free__tmpvar=NULL;                                  \
+    }                                                          \
+  STMT_END
+#else
 #define tor_free(p) STMT_BEGIN                                 \
    if (PREDICT_LIKELY((p)!=NULL)) {                           \
      raw_free(p);                                             \
      (p)=NULL;                                                \
    }                                                          \
  STMT_END
+#endif
 #endif /* defined(USE_DMALLOC) */

 #define tor_malloc(size)       tor_malloc_(size DMALLOC_ARGS)