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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug preprocessor/104147] [9/10 Regression] C preprocessor may remove the standard required whitespace between the preprocessing tokens Date: Wed, 11 May 2022 06:24:11 +0000 [thread overview] Message-ID: <bug-104147-4-lYYML0QB1O@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-104147-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104147 --- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:7157e074472435489963cf6961cd4c2d06804f4d commit r9-10121-g7157e074472435489963cf6961cd4c2d06804f4d Author: Jakub Jelinek <jakub@redhat.com> Date: Tue Feb 1 20:48:03 2022 +0100 libcpp: Fix up padding handling in funlike_invocation_p [PR104147] As mentioned in the PR, in some cases we preprocess incorrectly when we encounter an identifier which is defined as function-like macro, followed by at least 2 CPP_PADDING tokens and then some other identifier. On the following testcase, the problem is in the 3rd funlike_invocation_p, the tokens are CPP_NAME Y, CPP_PADDING (the pfile->avoid_paste shared token), CPP_PADDING (one created with padding_token, val.source is non-NULL and val.source->flags & PREV_WHITE is non-zero) and then another CPP_NAME. funlike_invocation_p remembers there was a padding token, but remembers the first one because of its condition, then the next token is the CPP_NAME, which is not CPP_OPEN_PAREN, so the CPP_NAME token is backed up, but as we can't easily backup more tokens, it pushes into a new context the padding token (the pfile->avoid_paste one). The net effect is that when Y is not defined as fun-like macro, we read Y, avoid_paste, padding_token, Y, while if Y is fun-like macro, we read Y, avoid_paste, avoid_paste, Y (the second avoid_paste is because that is how we handle end of a context). Now, for stringify_arg that is unfortunately a significant difference, which handles CPP_PADDING tokens with: if (token->type == CPP_PADDING) { if (source == NULL || (!(source->flags & PREV_WHITE) && token->val.source == NULL)) source = token->val.source; continue; } and later on /* Leading white space? */ if (dest - 1 != BUFF_FRONT (pfile->u_buff)) { if (source == NULL) source = token; if (source->flags & PREV_WHITE) *dest++ = ' '; } source = NULL; (and c-ppoutput.cc has similar code). So, when Y is not fun-like macro, ' ' is added because padding_token's val.source->flags & PREV_WHITE is non-zero, while when it is fun-like macro, we don't add ' ' in between, because source is NULL and so used from the next token (CPP_NAME Y), which doesn't have PREV_WHITE set. Now, the funlike_invocation_p condition if (padding == NULL || (!(padding->flags & PREV_WHITE) && token->val.source == NULL)) padding = token; looks very similar to that in stringify_arg/c-ppoutput.cc, so I assume the intent was to prefer do the same thing and pick the right padding. But there are significant differences. Both stringify_arg and c-ppoutput.cc don't remember the CPP_PADDING token, but its val.source instead, while in funlike_invocation_p we want to remember the padding token that has the significant information for stringify_arg/c-ppoutput.cc. So, IMHO we want to overwrite padding if: 1) padding == NULL (remember that there was any padding at all) 2) padding->val.source == NULL (this matches the source == NULL case in stringify_arg) 3) !(padding->val.source->flags & PREV_WHITE) && token->val.source == NULL (this matches the !(source->flags & PREV_WHITE) && token->val.source == NULL case in stringify_arg) 2022-02-01 Jakub Jelinek <jakub@redhat.com> PR preprocessor/104147 * macro.c (funlike_invocation_p): For padding prefer a token with val.source non-NULL especially if it has PREV_WHITE set on val.source->flags. Add gcc_assert that CPP_PADDING tokens don't have PREV_WHITE set in flags. * c-c++-common/cpp/pr104147.c: New test. (cherry picked from commit 95ac5635409606386259d2ff21fb61738858ca4a)
next prev parent reply other threads:[~2022-05-11 6:24 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-20 17:30 [Bug c/104147] New: " pavel.morozkin at gmail dot com 2022-01-20 20:59 ` [Bug preprocessor/104147] [9/10/11/12 Regression] " jsm28 at gcc dot gnu.org 2022-01-21 7:55 ` rguenth at gcc dot gnu.org 2022-01-31 14:07 ` jakub at gcc dot gnu.org 2022-01-31 14:50 ` jakub at gcc dot gnu.org 2022-02-01 19:50 ` cvs-commit at gcc dot gnu.org 2022-02-01 19:51 ` [Bug preprocessor/104147] [9/10/11 " jakub at gcc dot gnu.org 2022-02-19 8:02 ` cvs-commit at gcc dot gnu.org 2022-02-19 8:08 ` [Bug preprocessor/104147] [9/10 " jakub at gcc dot gnu.org 2022-05-10 8:23 ` cvs-commit at gcc dot gnu.org 2022-05-11 6:24 ` cvs-commit at gcc dot gnu.org [this message] 2022-05-11 6:36 ` jakub at gcc dot gnu.org
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