On 09/02/2018 17:40, Richard Biener wrote: > On February 9, 2018 5:08:24 PM GMT+01:00, Paolo Bonzini <bonz...@gnu.org> > wrote: >> Another possibility which I considered but did not implement is to mark >> the UNPOISON calls so that they do not cause the parameter to escape. > > I'd do this, thus assign proper fnspec attributes to the asan functions.
Hmm, actually that might be as simple as fixing a typo: diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def index 5970d0e..15d6151 100644 --- a/gcc/internal-fn.def +++ b/gcc/internal-fn.def @@ -255,8 +255,8 @@ DEF_INTERNAL_FN (UBSAN_PTR, ECF_LEAF | ECF_NOTHROW, ".R.") DEF_INTERNAL_FN (UBSAN_OBJECT_SIZE, ECF_LEAF | ECF_NOTHROW, NULL) DEF_INTERNAL_FN (ABNORMAL_DISPATCHER, ECF_NORETURN, NULL) DEF_INTERNAL_FN (BUILTIN_EXPECT, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL) -DEF_INTERNAL_FN (ASAN_CHECK, ECF_TM_PURE | ECF_LEAF | ECF_NOTHROW, ".R...") -DEF_INTERNAL_FN (ASAN_MARK, ECF_LEAF | ECF_NOTHROW, ".R..") +DEF_INTERNAL_FN (ASAN_CHECK, ECF_TM_PURE | ECF_LEAF | ECF_NOTHROW, "..R..") +DEF_INTERNAL_FN (ASAN_MARK, ECF_LEAF | ECF_NOTHROW, "..W.") DEF_INTERNAL_FN (ASAN_POISON, ECF_LEAF | ECF_NOTHROW | ECF_NOVOPS, NULL) DEF_INTERNAL_FN (ASAN_POISON_USE, ECF_LEAF | ECF_NOTHROW | ECF_NOVOPS, NULL) DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL) which indeed fixes the testcase and seems not to break asan.exp. 'W' is needed to avoid breaking the pr78541.c testcase, and I think it makes sense since ASAN_MARK is "writing" the state of the object (in the test case FRE moves a dereference across a poisoning). I'll look at it next week. Someone maybe should take a look at ubsan fnspecs too. Paolo
