Re: [PATCH] gdb: rename YYSTACKDATA in generated parsers

[Simon Marchi <simon.marchi@polymtl.ca>]

On 10/7/26 9:55 AM, simon.marchi@polymtl.ca wrote:
> From: Simon Marchi <simon.marchi@polymtl.ca>
> 
> When building with byacc and -flto -Werror=odr, we get:
> 
>     ada-exp-parser-gen.c.tmp:1552:3: error: type 'struct YYSTACKDATA' violates the C++ One Definition Rule [-Werror=odr]
>     c-exp-parser-gen.c.tmp:3732:3: note: a different type is defined in another translation unit
>     ada-exp-parser-gen.c.tmp:1546:30: note: the first difference of corresponding definitions is field 'l_base'
>     c-exp-parser-gen.c.tmp:3726:28: note: a field of same name but different type is defined in another translation unit
>     ada-exp-parser-gen.c.tmp:1552:3: note: type name 'ada_exp_parser_YYSTYPE' should match type name 'c_exp_parser_YYSTYPE'
> 
> The byacc generated parsers define this type:
> 
>     typedef struct {
>         unsigned stacksize;
>         YYINT    *s_base;
>         YYINT    *s_mark;
>         YYINT    *s_last;
>         YYSTYPE  *l_base;
>         YYSTYPE  *l_mark;
>         ...
>     } YYSTACKDATA;
> 
> Since YYSTYPE represents a different type in each parser (it is renamed
> to {prefix}_YYSTYPE by post-process-parser-output.sh), then YYSTACKDATA
> is also a different type in each parser, which leads to ODR violations.
> 
> This is a regression from my patch that removed yy-remap.h (d3d68d798e0c
> "gdb: let the parser and lexer generators prefix their symbols").
> yy-remap.h remapped YYSTACKDATA, since commit df940f8bb348 ("gdb: Fix an
> ODR warning with byacc with GDB_YY_REMAP") which fixed this exact
> problem.
> 
> Fix it by adding YYSTACKDATA to the renames done in
> post-process-parser-output.sh, alongside YYSTYPE and friends.
> 
> This is a master-only bug, no need to cherry-pick to gdb-18-branch.
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=34712
> Change-Id: I6332bd0edc6619434f67cccef463cd21e96e3251

Sam confirmed on Bugzilla that the patch fixes the problem, so I went
ahead and pushed it.

Simon