PING [PATCH] PR preprocessor/53469 - argument tokens of _Pragma miss virtual location

[Dodji Seketeli <dodji at redhat dot com>]

Hello

I am friendly pinging this patch that felt below my radar.

Dodji Seketeli <dodji@redhat.com> a Ãcrit:

> Hello,
>
> Consider this short test snippet:
>
> -------------------------8-------------------
>     #define STRINGIFY(x) #x
>     #define TEST(x) \
>       _Pragma(STRINGIFY(GCC diagnostic ignored "-Wunused-local-typedefs")) \
>       typedef int myint;
>
>     void bar ()
>     {
>       TEST(myint)
>     }
> -------------------------8-------------------
>
> The _Pragma is effectively ignored, and compiling with
> -Wunused-local-typedefs warns on the local typedef, even though the
> pragma should have prevented the warning to be emitted.
>
> This is because when the preprocessor sees the _Pragma operator and
> then goes to handle the first token ('GCC' here) that makes up its
> operands, it retains the spelling location of that token, not its
> virtual location.
>
> Later when diagnostic_report_diagnostic is called to emit the warning
> (or ignore it because of the pragma), it compares the location of the
> first operand of the pragma with the location of the unused location,
> (by calling linemap_location_before_p) and that comparison fails
> because in this case, both locations should be virtual.
>
> This patch fixes the issue by teaching the pragma handling to use
> virtual locations.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu against trunk.
>
> libcpp/
>
> 	PR preprocessor/53469
> 	* directives.c (do_pragma): Use the virtual location for the
> 	pragma token, instead of its spelling location.
>
> gcc/testsuite/
>
> 	PR preprocessor/53469
> 	* gcc.dg/cpp/_Pragma7.c: New test case.
> ---
>  gcc/testsuite/ChangeLog             |    5 +++++
>  gcc/testsuite/gcc.dg/cpp/_Pragma7.c |   14 ++++++++++++++
>  libcpp/ChangeLog                    |    6 ++++++
>  libcpp/directives.c                 |    8 +++++---
>  4 files changed, 30 insertions(+), 3 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/cpp/_Pragma7.c
>
> diff --git a/gcc/testsuite/gcc.dg/cpp/_Pragma7.c b/gcc/testsuite/gcc.dg/cpp/_Pragma7.c
> new file mode 100644
> index 0000000..a7a5b1b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/cpp/_Pragma7.c
> @@ -0,0 +1,14 @@
> +/*
> +  Origin: PR preprocessor/53469
> +  { dg-do compile }
> + */
> +
> +#define STRINGIFY(x) #x
> +#define TEST(x) \
> +  _Pragma(STRINGIFY(GCC diagnostic ignored "-Wunused-local-typedefs")) \
> +  typedef int myint;
> +
> +void bar ()
> +{
> +  TEST(myint)
> +}
> diff --git a/libcpp/directives.c b/libcpp/directives.c
> index e46280e..cd880f1 100644
> --- a/libcpp/directives.c
> +++ b/libcpp/directives.c
> @@ -1347,13 +1347,15 @@ static void
>  do_pragma (cpp_reader *pfile)
>  {
>    const struct pragma_entry *p = NULL;
> -  const cpp_token *token, *pragma_token = pfile->cur_token;
> +  const cpp_token *token, *pragma_token;
> +  source_location pragma_token_virt_loc = 0;
>    cpp_token ns_token;
>    unsigned int count = 1;
>  
>    pfile->state.prevent_expansion++;
>  
> -  token = cpp_get_token (pfile);
> +  pragma_token = token = cpp_get_token_with_location (pfile,
> +						      &pragma_token_virt_loc);
>    ns_token = *token;
>    if (token->type == CPP_NAME)
>      {
> @@ -1407,7 +1409,7 @@ do_pragma (cpp_reader *pfile)
>      {
>        if (p->is_deferred)
>  	{
> -	  pfile->directive_result.src_loc = pragma_token->src_loc;
> +	  pfile->directive_result.src_loc = pragma_token_virt_loc;
>  	  pfile->directive_result.type = CPP_PRAGMA;
>  	  pfile->directive_result.flags = pragma_token->flags;
>  	  pfile->directive_result.val.pragma = p->u.ident;

-- 
		Dodji