[gcc r12-6640] middle-end/101292 - invalid memory access with warning control

[Richard Biener]

https://gcc.gnu.org/g:1374d4b963a6ac2e0ec1645c09e5162e68b009d6

commit r12-6640-g1374d4b963a6ac2e0ec1645c09e5162e68b009d6
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Jan 17 15:22:11 2022 +0100

    middle-end/101292 - invalid memory access with warning control
    
    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.
    
    2022-01-17  Richard Biener  <rguenther@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.

Diff:
---
 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
 	{