[gcc r9-10120] libcpp: Avoid PREV_WHITE and other random content on CPP_PADDING tokens

[gcc r9-10120] libcpp: Avoid PREV_WHITE and other random content on CPP_PADDING tokens

[Jakub Jelinek]

https://gcc.gnu.org/g:7e05b86bcdd2ee9c53887b45e702e31d2e4aff46

commit r9-10120-g7e05b86bcdd2ee9c53887b45e702e31d2e4aff46
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Feb 1 20:42:49 2022 +0100

    libcpp: Avoid PREV_WHITE and other random content on CPP_PADDING tokens
    
    The funlike_invocation_p macro never triggered, the other
    asserts did on some tests, see below for a full list.
    This seems to be caused by #pragma/_Pragma handling.
    do_pragma does:
              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;
    when it sees a pragma, while start_directive does:
      pfile->directive_result.type = CPP_PADDING;
    and so does _cpp_do__Pragma.
    Now, for #pragma lex.cc will just ignore directive_result if
    it has CPP_PADDING type:
                  if (_cpp_handle_directive (pfile, result->flags & PREV_WHITE))
                    {
                      if (pfile->directive_result.type == CPP_PADDING)
                        continue;
                      result = &pfile->directive_result;
                    }
    but destringize_and_run does not:
      if (pfile->directive_result.type == CPP_PRAGMA)
        {
    ...
        }
      else
        {
          count = 1;
          toks = XNEW (cpp_token);
          toks[0] = pfile->directive_result;
    and from there it will copy type member of CPP_PADDING, but all the
    other members from the last CPP_PRAGMA before it.
    Small testcase for it with no option (at least no -fopenmp or -fopenmp-simd).
     #pragma GCC push_options
     #pragma GCC ignored "-Wformat"
     #pragma GCC pop_options
    void
    foo ()
    {
      _Pragma ("omp simd")
      for (int i = 0; i < 64; i++)
        ;
    }
    
    Here is a patch that replaces those
          toks = XNEW (cpp_token);
          toks[0] = pfile->directive_result;
    lines with
          toks = &pfile->avoid_paste;
    
    2022-02-01  Jakub Jelinek  <jakub@redhat.com>
    
            * directives.c (destringize_and_run): Push &pfile->avoid_paste
            instead of a copy of pfile->directive_result for the CPP_PADDING
            case.
    
    (cherry picked from commit efc46b550f035281e51c340f73fbc9a79655e852)

Diff:
---
 libcpp/directives.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libcpp/directives.c b/libcpp/directives.c
index d78e4b7fc19..a41fb90764f 100644
--- a/libcpp/directives.c
+++ b/libcpp/directives.c
@@ -1896,8 +1896,7 @@ destringize_and_run (cpp_reader *pfile, const cpp_string *in,
   else
     {
       count = 1;
-      toks = XNEW (cpp_token);
-      toks[0] = pfile->directive_result;
+      toks = &pfile->avoid_paste;
 
       /* If we handled the entire pragma internally, make sure we get the
 	 line number correct for the next token.  */