diff options
| author | Tom de Vries <tdevries@suse.de> | 2022-05-23 14:50:02 +0200 |
|---|---|---|
| committer | Tom de Vries <tdevries@suse.de> | 2022-05-23 14:50:02 +0200 |
| commit | 5a3cf18c2ed9593f194ea22f50ea5651532f6cfc (patch) | |
| tree | 4b617189ef5761bb5f892e09774bedf49865dc52 | |
| parent | 05527d8ca1082b4607e9ddc3209691f454b3b186 (diff) | |
| download | binutils-5a3cf18c2ed9593f194ea22f50ea5651532f6cfc.zip binutils-5a3cf18c2ed9593f194ea22f50ea5651532f6cfc.tar.gz binutils-5a3cf18c2ed9593f194ea22f50ea5651532f6cfc.tar.bz2 | |
[gdb/exp] Fix UB in scalar_binop
When building gdb with -fsanitize=undefined, I run into:
...
$ gdb -q -batch -ex "p -(-0x7fffffffffffffff - 1)"
src/gdb/valarith.c:1385:10: runtime error: signed integer overflow: \
0 - -9223372036854775808 cannot be represented in type 'long int'
$1 = -9223372036854775808
...
Fix this by performing the substraction in scalar_binop using unsigned types.
Tested on x86_64-linux.
| -rw-r--r-- | gdb/testsuite/gdb.base/arithmet.exp | 2 | ||||
| -rw-r--r-- | gdb/valarith.c | 5 |
2 files changed, 6 insertions, 1 deletions
diff --git a/gdb/testsuite/gdb.base/arithmet.exp b/gdb/testsuite/gdb.base/arithmet.exp index b6009a3..4905c2e 100644 --- a/gdb/testsuite/gdb.base/arithmet.exp +++ b/gdb/testsuite/gdb.base/arithmet.exp @@ -98,3 +98,5 @@ gdb_test "print x-(y+w)" "3" gdb_test "print x/(y*w)" "0" gdb_test "print x-(y/w)" "9" gdb_test "print (x+y)*w" "42" + +gdb_test "p /x -(-0x7fffffffffffffff - 1)" " = 0x8000000000000000" diff --git a/gdb/valarith.c b/gdb/valarith.c index 6210267..526cc02 100644 --- a/gdb/valarith.c +++ b/gdb/valarith.c @@ -1382,7 +1382,10 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op) break; case BINOP_SUB: - v = v1 - v2; + /* Avoid runtime error: signed integer overflow: \ + 0 - -9223372036854775808 cannot be represented in type + 'long int'. */ + v = (ULONGEST)v1 - (ULONGEST)v2; break; case BINOP_MUL: |