ggc: do not wipe out unrelated data via gt_ggc_rtab [PR111505]

There are 3 GC root tables:

   gt_ggc_rtab
   gt_ggc_deletable_rtab
   gt_pch_scalar_rtab

`deletable` and `scalar` tables are both simple: each element always
contains a pointer to the beginning of the object and it's size is the
full object.

`rtab` is different: it's `base` is a pointer in the middle of the
struct and `stride` points to the next GC pointer in the array.

Before the change there were 2 problems:

1. We memset()ed not just pointers but data around them.
2. We wen out of bounds of the last object described by gt_ggc_rtab
   and triggered bootstrap failures in profile and asan bootstraps.

After the change we handle only pointers themselves like the rest of
ggc-common.cc code.

gcc/
	PR middle-end/111505
	* ggc-common.cc (ggc_zero_out_root_pointers, ggc_common_finalize):
	Add new helper. Use helper instead of memset() to wipe out pointers.

0 files changed, 0 insertions, 0 deletions