Ping: [PATCH] libcpp: Fix ICE on directive inside _Pragma() operator [PR67046]

[Lewis Hyatt <lhyatt@gmail.com>]

Hello-

May I please ping this short patch that fixes an old bug? Thanks...

-Lewis

On Sat, Jan 14, 2023 at 1:46 PM Lewis Hyatt <lhyatt@gmail.com> wrote:
>
> get__Pragma_string() in directives.cc is responsible for lexing the parens
> and the string argument from a _Pragma("...") operator. This function does
> not handle the case when the closing paren is not on the same line as the
> string; in that case, libcpp will by default reuse the token buffer it
> previously used for the string, so that the string token returned by
> get__Pragma_string() may be corrupted, as shown in the testcase. Fix using
> the existing keep_tokens mechanism that temporarily disables the reuse of
> token buffers.
>
> libcpp/ChangeLog:
>
>         PR preprocessor/67046
>         * directives.cc (_cpp_do__Pragma): Increment pfile->keep_tokens to
>         ensure the returned string token is valid.
>
> gcc/testsuite/ChangeLog:
>
>         PR preprocessor/67046
>         * c-c++-common/cpp/pr67046.c: New test.
> ---
>
> Notes:
>     Hello-
>
>     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67046
>
>     This fixes an old ICE in libcpp that can happen when lexing the tokens from a
>     _Pragma operator. Bootstrapped+tested on x86-64 Linux with no
>     regressions. Please let me know if it's OK? Thanks...
>
>     -Lewis
>
>  gcc/testsuite/c-c++-common/cpp/pr67046.c | 10 ++++++++++
>  libcpp/directives.cc                     |  5 +++++
>  2 files changed, 15 insertions(+)
>  create mode 100644 gcc/testsuite/c-c++-common/cpp/pr67046.c
>
> diff --git a/gcc/testsuite/c-c++-common/cpp/pr67046.c b/gcc/testsuite/c-c++-common/cpp/pr67046.c
> new file mode 100644
> index 00000000000..f37f20c624e
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/cpp/pr67046.c
> @@ -0,0 +1,10 @@
> +/* { dg-do preprocess } */
> +
> +_Pragma(
> +"message(\"msg\")"
> +)
> +
> +_Pragma(
> +"message(\"msg\")"
> +#
> +)
> diff --git a/libcpp/directives.cc b/libcpp/directives.cc
> index 9dc4363c65a..ffd262bce7d 100644
> --- a/libcpp/directives.cc
> +++ b/libcpp/directives.cc
> @@ -1996,7 +1996,12 @@ destringize_and_run (cpp_reader *pfile, const cpp_string *in,
>  int
>  _cpp_do__Pragma (cpp_reader *pfile, location_t expansion_loc)
>  {
> +  /* Make sure we don't invalidate the string token, if the closing parenthesis
> +   ended up on a different line.  */
> +  ++pfile->keep_tokens;
>    const cpp_token *string = get__Pragma_string (pfile);
> +  --pfile->keep_tokens;
> +
>    pfile->directive_result.type = CPP_PADDING;
>
>    if (string)