On 12/19/20 12:48 AM, Richard Biener via Gcc-patches wrote:
On December 19, 2020 1:55:02 AM GMT+01:00, Martin Sebor via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
To keep tree expressions stored by the front end in attribute
access for nontrivial VLA bounds from getting corrupted during
Gimplification and to avoid breaking the preconditions verified
by the LTO streamer that no such trees exist in the IL,
the attached patch replaces those bounds with a string
representation of those expressions (as STRING_CST). It also
tweaks the pretty-printer to improve the formatting of the VLA
bounds and avoid inserting spurious spaces in some cases.
The strings are only used by the front end to verify that
redeclarations of the same function match in the form and bounds
of their VLA arguments, and they're not needed in the middle end.
I considered removing them just before the front end finishes but
I couldn't find an efficient way to do that. Is there some data
structure that stores all function declarations in a translation
unit? If there is, then traversing it and removing the attribute
arguments might also be an option, either in addition to this
change or in lieu of it.
There is the free lang data pass in tree.c which walks all reachable tree nodes.
You said in response to Honza's suggestion in pr97172 to do that:
The frontend needs to make sure no frontend specific tree codes
leak into GENERIC so GENERICization is the place where the FE
should clear those. FLD is too late and doing it there would
be a hack.
Are you now saying you've had a change of heart and that doing it
there isn't a hack after all?
Martin
The patch was tested on x86_64-linux.
Martin
