tor

commit b88281024579d5f207d15d1a2cc54c113f8a2bde
parent 2bb5d8148b2c15e9573a7f041ef631bdf4429b4b
Author: Nick Mathewson <nickm@torproject.org>
Date:   Wed, 15 May 2019 08:28:25 -0400

In coverage builds, use branch-free timeradd() and timersub()

The ordinary definitions of timeradd() and timersub() contain a
branch. However, in coverage builds, this means that we get spurious
complaints about partially covered basic blocks, in a way that makes
our coverage determinism harder to check.

Diffstat:
M
src/lib/wallclock/timeval.h
 | 
21
+++++++++++++++++++++

1 file changed, 21 insertions(+), 0 deletions(-)
diff --git a/src/lib/wallclock/timeval.h b/src/lib/wallclock/timeval.h
@@ -20,6 +20,27 @@
 #include <sys/time.h>
 #endif
 
+#ifdef TOR_COVERAGE
+/* For coverage builds, we use a slower definition of these macros without
+ * branches, to make coverage consistent. */
+#undef timeradd
+#undef timersub
+#define timeradd(tv1,tv2,tvout) \
+  do {                          \
+    (tvout)->tv_sec = (tv1)->tv_sec + (tv2)->tv_sec;    \
+    (tvout)->tv_usec = (tv1)->tv_usec + (tv2)->tv_usec; \
+    (tvout)->tv_sec += (tvout)->tv_usec / 1000000;      \
+    (tvout)->tv_usec %= 1000000;                        \
+  } while (0)
+#define timersub(tv1,tv2,tvout) \
+  do {                          \
+    (tvout)->tv_sec = (tv1)->tv_sec - (tv2)->tv_sec - 1;            \
+    (tvout)->tv_usec = (tv1)->tv_usec - (tv2)->tv_usec + 1000000;   \
+    (tvout)->tv_sec += (tvout)->tv_usec / 1000000;                  \
+    (tvout)->tv_usec %= 1000000;                                    \
+  } while (0)
+#endif
+
 #ifndef timeradd
 /** Replacement for timeradd on platforms that do not have it: sets tvout to
  * the sum of tv1 and tv2. */