[Bug c++/100646] New: gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[Bug c++/100646] New: gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[mtekieli+gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

            Bug ID: 100646
           Summary: gcc -E -fdirectives-only causes "error: unterminated
                    comment" when no new line at the end of file
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mtekieli+gcc at gmail dot com
  Target Milestone: ---

$ cat test_gcc11.cpp 
int main()
{
}
// namespace

$ g++ -E -fdirectives-only test_gcc11.cpp -o test_gcc11.o
test_gcc11.cpp:4:1: error: unterminated comment
    4 | // namespace
      | ^

Above error occurs when test_gcc11.cpp or anything included in test_gcc11.cpp
has a comment with no new line at the end of file.

It looks like this patch does not help:
https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b6ecd493886891f8150905a2fd3b7d54e88fc7be

It worked fine with gcc 10.

[Bug c++/100646] [11/12 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-05-18
      Known to work|                            |10.3.1
   Target Milestone|---                         |11.2
           Priority|P3                          |P2
            Summary|gcc -E -fdirectives-only    |[11/12 Regression] gcc -E
                   |causes "error: unterminated |-fdirectives-only causes
                   |comment" when no new line   |"error: unterminated
                   |at the end of file          |comment" when no new line
                   |                            |at the end of file

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug c++/100646] [11/12 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic, error-recovery,
                   |                            |ice-on-invalid-code
                 CC|                            |egallager at gcc dot gnu.org

--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
It took a bit of effort to get a text editor to save the file without a newline
at EOF, but once I did that, the error for me was an ICE instead of a regular
error:
100646.c:1: internal compiler error: in cpp_directive_only_process, at
libcpp/lex.c:3950
    1 | int main()
      | 
I'll attach the full output as an attachment. This happens regardless of
whether I compile it as plain C, or C++.
(although it has been awhile since I last rebuilt GCC, so that could be the
issue...)
Here's my version and configuration info:

$ /usr/local/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/usr/local/bin/gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-apple-darwin19.6.0/11.0.0/lto-wrapper
Target: x86_64-apple-darwin19.6.0
Configured with: ../configure --disable-werror --disable-werror-always
--enable-languages=all,c,c++,objc,obj-c++,lto
--enable-stage1-checking=release,rtl -C --with-system-libunwind
--enable-secureplt --enable-frame-pointer --enable-debug --without-isl
--disable-host-shared --disable-maintainer-mode --disable-default-pie
--with-ld64 --without-pic --enable-target-optspace --disable-nls
--with-system-zlib --with-libiconv-prefix=/opt/local --with-gmp=/opt/local
--with-mpfr=/opt/local --with-mpc=/opt/local --enable-lto
--with-build-config=bootstrap-debug --enable-objc-gc --enable-libada
--enable-libssp --disable-libsanitizer
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk
--disable-gcov : (reconfigured) ../configure --disable-werror
--disable-werror-always --enable-languages=all,c,c++,objc,obj-c++,lto
--enable-stage1-checking=release,rtl -C --with-system-libunwind
--enable-secureplt --enable-frame-pointer --enable-debug --without-isl
--disable-host-shared --disable-maintainer-mode --disable-default-pie
--with-ld64 --without-pic --enable-target-optspace --disable-nls
--with-system-zlib --with-libiconv-prefix=/opt/local --with-gmp=/opt/local
--with-mpfr=/opt/local --with-mpc=/opt/local --enable-lto
--with-build-config=bootstrap-debug --disable-objc-gc --enable-libada
--enable-libssp --disable-libsanitizer
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk
--disable-gcov
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200920 (experimental) (GCC)
$

[Bug c++/100646] [11/12 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

--- Comment #3 from Eric Gallager <egallager at gcc dot gnu.org> ---
Created attachment 50834
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50834&action=edit
terminal output from attempting to compile testcase

[Bug c++/100646] [11/12 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:d15a2d261b24adcbfe5e663b15dde3df5d2b3486

commit r12-934-gd15a2d261b24adcbfe5e663b15dde3df5d2b3486
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu May 20 09:09:07 2021 +0200

    libcpp: Fix up -fdirectives-only handling of // comments on last line not
terminated with newline [PR100646]

    As can be seen on the testcases, before the -fdirectives-only preprocessing
    rewrite the preprocessor would assume // comments are terminated by the
    end of file even when newline wasn't there, but now we error out.
    The following patch restores the previous behavior.

    2021-05-20  Jakub Jelinek  <jakub@redhat.com>

            PR preprocessor/100646
            * lex.c (cpp_directive_only_process): Treat end of file as
termination
            for !is_block comments.

            * gcc.dg/cpp/pr100646-1.c: New test.
            * gcc.dg/cpp/pr100646-2.c: New test.

[Bug c++/100646] [11 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
            Summary|[11/12 Regression] gcc -E   |[11 Regression] gcc -E
                   |-fdirectives-only causes    |-fdirectives-only causes
                   |"error: unterminated        |"error: unterminated
                   |comment" when no new line   |comment" when no new line
                   |at the end of file          |at the end of file

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed on the trunk so far.

[Bug c++/100646] [11 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:3a2fa2e819d4714cecf5048eda2b7e52ba9e3cdd

commit r11-8490-g3a2fa2e819d4714cecf5048eda2b7e52ba9e3cdd
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu May 20 09:09:07 2021 +0200

    libcpp: Fix up -fdirectives-only handling of // comments on last line not
terminated with newline [PR100646]

    As can be seen on the testcases, before the -fdirectives-only preprocessing
    rewrite the preprocessor would assume // comments are terminated by the
    end of file even when newline wasn't there, but now we error out.
    The following patch restores the previous behavior.

    2021-05-20  Jakub Jelinek  <jakub@redhat.com>

            PR preprocessor/100646
            * lex.c (cpp_directive_only_process): Treat end of file as
termination
            for !is_block comments.

            * gcc.dg/cpp/pr100646-1.c: New test.
            * gcc.dg/cpp/pr100646-2.c: New test.

    (cherry picked from commit d15a2d261b24adcbfe5e663b15dde3df5d2b3486)

[Bug c++/100646] [11 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 11.2.

[Bug c++/100646] [11 Regression] gcc -E -fdirectives-only causes "error: unterminated comment" when no new line at the end of file

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100646

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |boris at kolpackov dot net

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
*** Bug 101298 has been marked as a duplicate of this bug. ***