Re: [PATCH] preprocessor: Create the parser before handling command-line includes [PR115312]

[Marek Polacek <polacek@redhat.com>]

On Thu, Jun 27, 2024 at 05:06:14PM -0400, Lewis Hyatt wrote:
> Hello-
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115312
> 
> This fixes a 14.1 regression with PCH for MinGW and other platforms that don't
> use stdc-predef.h. Bootstrap + regtest all languages on x86-64 Linux;
> bootstrap + regtest c,c++ on x86_64-w64-mingw32. Is it OK for 14 branch and
> master please? Thanks!
 
The patch looks good to me.  I think you can push it next week if there
are no objections.

Reviewed-by: Marek Polacek <polacek@redhat.com>

> -- >8 --
> 
> Since r14-2893, we create a parser object in preprocess-only mode for the
> purpose of parsing #pragma while preprocessing. The parser object was
> formerly created after calling c_finish_options(), which leads to problems
> on platforms that don't use stdc-predef.h (such as MinGW, as reported in
> the PR). On such platforms, the call to c_finish_options() will process
> the first command-line-specified include file. If that includes a PCH, then
> c-ppoutput.cc will encounter a state it did not anticipate. Fix it by
> creating the parser prior to calling c_finish_options().
> 
> gcc/c-family/ChangeLog:
> 
> 	PR pch/115312
> 	* c-opts.cc (c_common_init): Call c_init_preprocess() before
> 	c_finish_options() so that a parser is available to process any
> 	includes specified on the command line.
> 
> gcc/testsuite/ChangeLog:
> 
> 	PR pch/115312
> 	* g++.dg/pch/pr115312.C: New test.
> 	* g++.dg/pch/pr115312.Hs: New test.
> ---
>  gcc/c-family/c-opts.cc               | 2 +-
>  gcc/testsuite/g++.dg/pch/pr115312.C  | 2 ++
>  gcc/testsuite/g++.dg/pch/pr115312.Hs | 1 +
>  3 files changed, 4 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/g++.dg/pch/pr115312.C
>  create mode 100644 gcc/testsuite/g++.dg/pch/pr115312.Hs
> 
> diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
> index 33114f13c8d..b7789b707e6 100644
> --- a/gcc/c-family/c-opts.cc
> +++ b/gcc/c-family/c-opts.cc
> @@ -1296,8 +1296,8 @@ c_common_init (void)
>  
>    if (flag_preprocess_only)
>      {
> -      c_finish_options ();
>        c_init_preprocess ();
> +      c_finish_options ();
>        preprocess_file (parse_in);
>        return false;
>      }
> diff --git a/gcc/testsuite/g++.dg/pch/pr115312.C b/gcc/testsuite/g++.dg/pch/pr115312.C
> new file mode 100644
> index 00000000000..9074ad4a5ad
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pch/pr115312.C
> @@ -0,0 +1,2 @@
> +/* { dg-additional-options "-include pr115312.H -save-temps" } */
> +#error "suppress PCH assembly comparison, which does not work with -save-temps" /* { dg-error "." } */
> diff --git a/gcc/testsuite/g++.dg/pch/pr115312.Hs b/gcc/testsuite/g++.dg/pch/pr115312.Hs
> new file mode 100644
> index 00000000000..6e7c6bcac2f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pch/pr115312.Hs
> @@ -0,0 +1 @@
> +// This space intentionally left blank.
> 

Marek