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Re: [PATCH] Fix PR66805 - #pragma pack affecting gcov_info_type layout
- From: Richard Biener <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Jakub Jelinek <jakub at redhat dot com>
- Date: Wed, 8 Jul 2015 14:08:38 +0200 (CEST)
- Subject: Re: [PATCH] Fix PR66805 - #pragma pack affecting gcov_info_type layout
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot LSU dot 2 dot 11 dot 1507081355000 dot 9923 at zhemvz dot fhfr dot qr>
On Wed, 8 Jul 2015, Richard Biener wrote:
>
> The following fixes #pragma pack effect leaking to all types built
> from the middle-end (so possibly even vector types built by the
> vectorizer?). The PR in question is about gcov_info_type where
> layout is affected and inconsistency between that and the libgcov.a
> copy causes libgcov to crash.
>
> As the way to communicate #pragma pack to stor-layout.c is already
> a hack I couldn't think of a better solution like that below.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> Ok?
Ok, so I found initial_max_fld_align and instead propose the following
simpler.
2015-07-08 Richard Biener <rguenther@suse.de>
* toplev.c (compile_file): Reset maximum_field_alignment after parsing.
Index: gcc/toplev.c
===================================================================
--- gcc/toplev.c (revision 225534)
+++ gcc/toplev.c (working copy)
@@ -553,6 +553,11 @@ compile_file (void)
if (flag_syntax_only || flag_wpa)
return;
+
+ /* Reset maximum_field_alignment, it can be adjusted by #pragma pack
+ and this shouldn't influence any types built by the middle-end
+ from now on (like gcov_info_type). */
+ maximum_field_alignment = initial_max_fld_align * BITS_PER_UNIT;
ggc_protect_identifiers = false;