commit 16f2c753f9959e8d7c7e1fa771b8ccc5821427aa
author Paul Kehrer <paul.l.kehrer@gmail.com> Sat Jun 08 10:06:40 2019 -0400
committer Mark Wielaard <mark@klomp.org> Mon Jun 24 15:24:21 2019 +0200
tree 67ba6a528c0b57a51acaeac2e1ef5ae5d8229369
parent f51f164df0e8a2c0e055174b328b4038a040e547

Fix undefined behavior in the macros SET_BH, CLEAR_BH, & ISSET_BH

These macros contain this pattern:
1 << ((Int32_value) & 31

This causes the undefined behavior sanitizers in clang and gcc to
complain because the shift, while ultimately stored to an unsigned
variable, is done as a signed value. Adding a cast to unsigned for
the int32 value resolves this issue.

blocksort.c

diff --git a/blocksort.c b/blocksort.c
index 830d1b4..aa36766 100644
--- a/blocksort.c
+++ b/blocksort.c
@@ -202,9 +202,9 @@
       bhtab [ 0 .. 2+(nblock/32) ] destroyed
 */
 
-#define       SET_BH(zz)  bhtab[(zz) >> 5] |= (1 << ((zz) & 31))
-#define     CLEAR_BH(zz)  bhtab[(zz) >> 5] &= ~(1 << ((zz) & 31))
-#define     ISSET_BH(zz)  (bhtab[(zz) >> 5] & (1 << ((zz) & 31)))
+#define       SET_BH(zz)  bhtab[(zz) >> 5] |= ((UInt32)1 << ((zz) & 31))
+#define     CLEAR_BH(zz)  bhtab[(zz) >> 5] &= ~((UInt32)1 << ((zz) & 31))
+#define     ISSET_BH(zz)  (bhtab[(zz) >> 5] & ((UInt32)1 << ((zz) & 31)))
 #define      WORD_BH(zz)  bhtab[(zz) >> 5]
 #define UNALIGNED_BH(zz)  ((zz) & 0x01f)