Hi! Back in 2020 Nathan rewrote the -E -fdirectives-only preprocessing. In PR103130 a year and half later I've fixed the handling of comments so that /* \*/ is considered as full comment even when * is escaped, to match the normal preprocessing. The following testcases shows further bugs in the comment handling. One is that /* *\/ should not be considered as full comment (i.e. when the / after * is escaped). And another one is that the code was treating any number of backslashes as escape, which is wrong, only a single backslash is an escape, two backslashes preprocess as one backslash, three as one backslash and one escape, etc. So, while /* *\ / is a full comment, /* *\\ / or /* *\\\\\\\\\\\\\ / is not.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2026-01-06 Jakub Jelinek <[email protected]> PR preprocessor/123273 * lex.cc (cpp_directive_only_process): Only go to done_comment for '/' if star is true and esc is false. When seeing '\\' with esc set to true, clear esc as well as star instead of keeping esc set. * c-c++-common/cpp/dir-only-10.c: New test. * c-c++-common/cpp/dir-only-11.c: New test. --- libcpp/lex.cc.jj 2026-01-02 09:56:10.417332292 +0100 +++ libcpp/lex.cc 2026-01-05 16:40:26.413766032 +0100 @@ -5461,7 +5461,13 @@ cpp_directive_only_process (cpp_reader * switch (c) { case '\\': - esc = true; + if (esc) + { + star = false; + esc = false; + } + else + esc = true; break; case '\r': @@ -5492,7 +5498,7 @@ cpp_directive_only_process (cpp_reader * break; case '/': - if (star) + if (star && !esc) goto done_comment; /* FALLTHROUGH */ --- gcc/testsuite/c-c++-common/cpp/dir-only-10.c.jj 2026-01-05 17:04:26.144566116 +0100 +++ gcc/testsuite/c-c++-common/cpp/dir-only-10.c 2026-01-05 17:05:02.226946201 +0100 @@ -0,0 +1,5 @@ +/* PR preprocessor/123273 */ +/* { dg-do preprocess } */ +/* { dg-options -fdirectives-only } */ + +/* *\/""" */ --- gcc/testsuite/c-c++-common/cpp/dir-only-11.c.jj 2026-01-05 17:05:18.498666647 +0100 +++ gcc/testsuite/c-c++-common/cpp/dir-only-11.c 2026-01-05 17:06:17.574651691 +0100 @@ -0,0 +1,6 @@ +/* PR preprocessor/123273 */ +/* { dg-do preprocess } */ +/* { dg-options -fdirectives-only } */ + +/* *\\ +/""" */ Jakub
