diff options
| author | Nick Mathewson <nickm@torproject.org> | 2018-10-15 10:34:39 -0400 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2018-10-15 10:34:39 -0400 |
| commit | b113399658934f3a4526387a63429ec4377ca8be (patch) | |
| tree | e7d99041851a615fa60e52e8d153b453a9237aef | |
| parent | 717507e3bb38d11814f4128ed7ccde676ab2aa89 (diff) | |
| parent | 5e582c7ffafd9075373131e5e55b69507f54206e (diff) | |
| download | tor-b113399658934f3a4526387a63429ec4377ca8be.tar.gz tor-b113399658934f3a4526387a63429ec4377ca8be.zip | |
Merge branch 'bug27709_029' into maint-0.2.9
| -rw-r--r-- | changes/bug27709 | 4 | ||||
| -rw-r--r-- | src/common/util_bug.h | 57 |
2 files changed, 48 insertions, 13 deletions
diff --git a/changes/bug27709 b/changes/bug27709 new file mode 100644 index 0000000000..49e87cbb0a --- /dev/null +++ b/changes/bug27709 @@ -0,0 +1,4 @@ + o Minor bugfixes (code safety): + - Rewrite our assertion macros so that they no longer suppress + the compiler's -Wparentheses warnings on their inputs. Fixes bug 27709; + bugfix on 0.0.6. diff --git a/src/common/util_bug.h b/src/common/util_bug.h index 0695806911..f3e5b7c963 100644 --- a/src/common/util_bug.h +++ b/src/common/util_bug.h @@ -29,6 +29,35 @@ #error "Sorry; we don't support building with NDEBUG." #endif +#if defined(TOR_UNIT_TESTS) && defined(__GNUC__) +/* We define this GCC macro as a replacement for PREDICT_UNLIKELY() in this + * header, so that in our unit test builds, we'll get compiler warnings about + * stuff like tor_assert(n = 5). + * + * The key here is that (e) is wrapped in exactly one layer of parentheses, + * and then passed right to a conditional. If you do anything else to the + * expression here, or introduce any more parentheses, the compiler won't + * help you. + * + * We only do this for the unit-test build case because it interferes with + * the likely-branch labeling. Note below that in the other case, we define + * these macros to just be synonyms for PREDICT_(UN)LIKELY. + */ +#define ASSERT_PREDICT_UNLIKELY_(e) \ + ({ \ + int tor__assert_tmp_value__; \ + if (e) \ + tor__assert_tmp_value__ = 1; \ + else \ + tor__assert_tmp_value__ = 0; \ + tor__assert_tmp_value__; \ + }) +#define ASSERT_PREDICT_LIKELY_(e) ASSERT_PREDICT_UNLIKELY_(e) +#else +#define ASSERT_PREDICT_UNLIKELY_(e) PREDICT_UNLIKELY(e) +#define ASSERT_PREDICT_LIKELY_(e) PREDICT_LIKELY(e) +#endif + /* Sometimes we don't want to use assertions during branch coverage tests; it * leads to tons of unreached branches which in reality are only assertions we * didn't hit. */ @@ -40,7 +69,8 @@ /** Like assert(3), but send assertion failures to the log as well as to * stderr. */ #define tor_assert(expr) STMT_BEGIN \ - if (PREDICT_UNLIKELY(!(expr))) { \ + if (ASSERT_PREDICT_LIKELY_(expr)) { \ + } else { \ tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__, #expr); \ abort(); \ } STMT_END @@ -77,7 +107,7 @@ #define tor_assert_nonfatal_unreached_once() tor_assert(0) #define tor_assert_nonfatal_once(cond) tor_assert((cond)) #define BUG(cond) \ - (PREDICT_UNLIKELY(cond) ? \ + (ASSERT_PREDICT_UNLIKELY_(cond) ? \ (tor_assertion_failed_(SHORT_FILE__,__LINE__,__func__,"!("#cond")"), \ abort(), 1) \ : 0) @@ -86,14 +116,15 @@ #define tor_assert_nonfatal(cond) ((void)(cond)) #define tor_assert_nonfatal_unreached_once() STMT_NIL #define tor_assert_nonfatal_once(cond) ((void)(cond)) -#define BUG(cond) (PREDICT_UNLIKELY(cond) ? 1 : 0) +#define BUG(cond) (ASSERT_PREDICT_UNLIKELY_(cond) ? 1 : 0) #else /* Normal case, !ALL_BUGS_ARE_FATAL, !DISABLE_ASSERTS_IN_UNIT_TESTS */ #define tor_assert_nonfatal_unreached() STMT_BEGIN \ tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 0); \ STMT_END #define tor_assert_nonfatal(cond) STMT_BEGIN \ - if (PREDICT_UNLIKELY(!(cond))) { \ - tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0); \ + if (ASSERT_PREDICT_LIKELY_(cond)) { \ + } else { \ + tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0); \ } \ STMT_END #define tor_assert_nonfatal_unreached_once() STMT_BEGIN \ @@ -105,13 +136,14 @@ STMT_END #define tor_assert_nonfatal_once(cond) STMT_BEGIN \ static int warning_logged__ = 0; \ - if (!warning_logged__ && PREDICT_UNLIKELY(!(cond))) { \ + if (ASSERT_PREDICT_LIKELY_(cond)) { \ + } else if (!warning_logged__) { \ warning_logged__ = 1; \ tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 1); \ } \ STMT_END #define BUG(cond) \ - (PREDICT_UNLIKELY(cond) ? \ + (ASSERT_PREDICT_UNLIKELY_(cond) ? \ (tor_bug_occurred_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",0), 1) \ : 0) #endif @@ -120,17 +152,17 @@ #define IF_BUG_ONCE__(cond,var) \ if (( { \ static int var = 0; \ - int bool_result = (cond); \ - if (PREDICT_UNLIKELY(bool_result) && !var) { \ + int bool_result = !!(cond); \ + if (bool_result && !var) { \ var = 1; \ tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, \ "!("#cond")", 1); \ } \ - PREDICT_UNLIKELY(bool_result); } )) + bool_result; } )) #else #define IF_BUG_ONCE__(cond,var) \ static int var = 0; \ - if (PREDICT_UNLIKELY(cond) ? \ + if ((cond) ? \ (var ? 1 : \ (var=1, \ tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, \ @@ -148,7 +180,7 @@ */ #define IF_BUG_ONCE(cond) \ - IF_BUG_ONCE__((cond), \ + IF_BUG_ONCE__(ASSERT_PREDICT_UNLIKELY_(cond), \ IF_BUG_ONCE_VARNAME__(__LINE__)) /** Define this if you want Tor to crash when any problem comes up, @@ -170,4 +202,3 @@ void tor_set_failed_assertion_callback(void (*fn)(void)); #endif #endif - |