[Bug c/103415] New: [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[Bug c/103415] New: [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

            Bug ID: 103415
           Summary: [12 Regression] ICE in cpp_interpret_string_1, at
                    libcpp/charset.c:1739
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Started between 20210808 and 20210822  :


$ cat z1.c
#define n(x...) = #__VA_OPT__(x##1)
const char *c n(1, 2);


$ gcc-12-20211121 -c z1.c
z1.c:1:20: warning: __VA_OPT__ can only appear in the expansion of a C++20
variadic macro
    1 | #define n(x...) = #__VA_OPT__(x##1)
      |                    ^
z1.c:2:1: internal compiler error: in cpp_interpret_string_1, at
libcpp/charset.c:1739
    2 | const char *c n(1, 2);
      | ^~~~~
0x18b9877 cpp_interpret_string_1
        ../../libcpp/charset.c:1739
0x18b9aed cpp_interpret_string(cpp_reader*, cpp_string const*, unsigned long,
cpp_string*, cpp_ttype)
        ../../libcpp/charset.c:1819
0x78aad3 c_parser_string_literal(c_parser*, bool, bool)
        ../../gcc/c/c-parser.c:7410
0x78b528 c_parser_postfix_expression
        ../../gcc/c/c-parser.c:9023
0x795b12 c_parser_unary_expression
        ../../gcc/c/c-parser.c:8255
0x796b5f c_parser_cast_expression
        ../../gcc/c/c-parser.c:8097
0x796e19 c_parser_binary_expression
        ../../gcc/c/c-parser.c:7900
0x79800b c_parser_conditional_expression
        ../../gcc/c/c-parser.c:7600
0x7986d1 c_parser_expr_no_commas
        ../../gcc/c/c-parser.c:7515
0x79eaf9 c_parser_initializer
        ../../gcc/c/c-parser.c:5212
0x7aef2a c_parser_declaration_or_fndef
        ../../gcc/c/c-parser.c:2282
0x7b70cf c_parser_external_declaration
        ../../gcc/c/c-parser.c:1780
0x7b79fb c_parser_translation_unit
        ../../gcc/c/c-parser.c:1653
0x7b79fb c_parse_file()
        ../../gcc/c/c-parser.c:23280
0x808eb2 c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1240

[Bug c/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

G. Steinmetz <gscfq@t-online.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code

--- Comment #1 from G. Steinmetz <gscfq@t-online.de> ---

Probably related :


$ cat z2.c
#define n(x...) #__VA_OPT__(x##__VA_ARGS__##c)
const char *c n(1)


$ cat z3.c
#define n(x...) = #__VA_OPT__(x##__VA_ARGS__##c)
const char *c n(1);


$ gcc-12-20211121 -c z2.c
z2.c:1:18: warning: __VA_OPT__ can only appear in the expansion of a C++20
variadic macro
    1 | #define n(x...) #__VA_OPT__(x##__VA_ARGS__##c)
      |                  ^
z2.c:1:32: warning: __VA_ARGS__ can only appear in the expansion of a C99
variadic macro
    1 | #define n(x...) #__VA_OPT__(x##__VA_ARGS__##c)
      |                                ^
z2.c:2:1: internal compiler error: Segmentation fault
    2 | const char *c n(1)
      | ^~~~~
0xcb463f crash_signal
        ../../gcc/toplev.c:322
0x18d0cca new_string_token
        ../../libcpp/macro.c:472
0x18d0cca stringify_arg
        ../../libcpp/macro.c:941
0x18d32e3 replace_args
        ../../libcpp/macro.c:2068
0x18d32e3 enter_macro_context
        ../../libcpp/macro.c:1496
0x18d3750 cpp_get_token_1
        ../../libcpp/macro.c:2986
0x7ff27d c_lex_with_flags(tree_node**, unsigned int*, unsigned char*, int)
        ../../gcc/c-family/c-lex.c:483
0x78743f c_lex_one_token
        ../../gcc/c/c-parser.c:279
0x788414 c_parser_peek_nth_token(c_parser*, unsigned int)
        ../../gcc/c/c-parser.c:517
0x7889a0 c_parser_nth_token_starts_std_attributes
        ../../gcc/c/c-parser.c:5092
0x79524b c_parser_direct_declarator
        ../../gcc/c/c-parser.c:3951
0x79524b c_parser_declarator(c_parser*, bool, c_dtr_syn, bool*)
        ../../gcc/c/c-parser.c:3894
0x795033 c_parser_declarator(c_parser*, bool, c_dtr_syn, bool*)
        ../../gcc/c/c-parser.c:3886
0x7ae573 c_parser_declaration_or_fndef
        ../../gcc/c/c-parser.c:2154
0x7b70cf c_parser_external_declaration
        ../../gcc/c/c-parser.c:1780
0x7b79fb c_parser_translation_unit
        ../../gcc/c/c-parser.c:1653
0x7b79fb c_parse_file()
        ../../gcc/c/c-parser.c:23280
0x808eb2 c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1240

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.0

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-11-25
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.


(In reply to G. Steinmetz from comment #0)
> Started between 20210808 and 20210822  :

Then it is when __VA_OPT__ support was added in r12-2940-gd56599979211266b.

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> Confirmed.
> 
> 
> (In reply to G. Steinmetz from comment #0)
> > Started between 20210808 and 20210822  :
> 
> Then it is when __VA_OPT__ support was added in r12-2940-gd56599979211266b.

Yes, it started with the revision.

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
__VA_OPT__ has been supported for a few more years, my change just added
support for stringification of __VA_OPT__...

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 51873
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51873&action=edit
gcc12-pr103415.patch

Untested fix.

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

--- Comment #6 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:ac5fd364f0978c62ae759e7b36ce6b912a27546c

commit r12-5651-gac5fd364f0978c62ae759e7b36ce6b912a27546c
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Dec 1 10:07:59 2021 +0100

    libcpp: Fix up #__VA_OPT__ handling [PR103415]

    stringify_arg uses pfile->u_buff to create the string literal.
    Unfortunately, paste_tokens -> _cpp_lex_direct -> lex_number ->
_cpp_unaligned_alloc
    can in some cases use pfile->u_buff too, which results in losing everything
    prepared for the string literal until the token pasting.

    The following patch fixes that by not calling paste_token during the
    construction of the string literal, but doing that before.  All the tokens
    we are processing have been pushed into a token buffer using
    tokens_buff_add_token so it is fine if we paste some of them in that buffer
    (successful pasting creates a new token in that buffer), move following
    tokens if any to make it contiguous, pop (throw away) the extra tokens at
    the end and then do stringify_arg.

    Also, paste_tokens now copies over PREV_WHITE and PREV_FALLTHROUGH flags
    from the original lhs token to the replacement token.  Copying that way
    the PREV_WHITE flag is needed for the #__VA_OPT__ handling and copying
    over PREV_FALLTHROUGH fixes the new Wimplicit-fallthrough-38.c test.

    2021-12-01  Jakub Jelinek  <jakub@redhat.com>

            PR preprocessor/103415
    libcpp/
            * macro.c (stringify_arg): Remove va_opt argument and va_opt
handling.
            (paste_tokens): On successful paste or in PREV_WHITE and
            PREV_FALLTHROUGH flags from the *plhs token to the new token.
            (replace_args): Adjust stringify_arg callers.  For #__VA_OPT__,
            perform token pasting in a separate loop before stringify_arg call.
    gcc/testsuite/
            * c-c++-common/cpp/va-opt-8.c: New test.
            * c-c++-common/Wimplicit-fallthrough-38.c: New test.

[Bug preprocessor/103415] [12 Regression] ICE in cpp_interpret_string_1, at libcpp/charset.c:1739

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103415

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

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

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