On 1/17/22 07:32, Richard Biener via Gcc-patches wrote:
The warning control falls into the C++ trap of using a reference to old hashtable contents for a put operation which can end up re-allocating that before reading from the old freed referenced to source. Fixed by introducing a temporary.
I think a better place to fix this and avoid the gotcha once and for all is in the GCC hash_map: C++ containers are expected to handle the insertion of own elements gracefully. Martin
Bootstrap & regtest running on x86_64-unknown-linux-gnu. 2022-01-17 Richard Biener <rguent...@suse.de> PR middle-end/101292 * diagnostic-spec.c (copy_warning): Make sure to not reference old hashtable content on possible resize. * warning-control.cc (copy_warning): Likewise. --- gcc/diagnostic-spec.c | 5 ++++- gcc/warning-control.cc | 3 ++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/gcc/diagnostic-spec.c b/gcc/diagnostic-spec.c index a8af229d677..4341ccfaae9 100644 --- a/gcc/diagnostic-spec.c +++ b/gcc/diagnostic-spec.c @@ -195,7 +195,10 @@ copy_warning (location_t to, location_t from) else { if (from_spec) - nowarn_map->put (to, *from_spec); + { + nowarn_spec_t tem = *from_spec; + nowarn_map->put (to, tem); + } else nowarn_map->remove (to); } diff --git a/gcc/warning-control.cc b/gcc/warning-control.cc index f9808bf4392..fa39ecab421 100644 --- a/gcc/warning-control.cc +++ b/gcc/warning-control.cc @@ -206,7 +206,8 @@ void copy_warning (ToType to, FromType from) gcc_assert (supp);gcc_checking_assert (nowarn_map);- nowarn_map->put (to_loc, *from_spec); + nowarn_spec_t tem = *from_spec; + nowarn_map->put (to_loc, tem); } else {
