On Wed, Sep 11, 2024 at 5:28 PM Jakub Jelinek <ja...@redhat.com> wrote:
>
> Hi!
>
> The following patch implements the clang -Wheader-guard warning, which warns
> if a valid multiple inclusion header guard's #ifndef/#if !defined directive
> is immediately (no other non-line directives nor other (non-comment)
> tokens in between) followed by #define directive for some different macro,
> which in get_suggestion rules is close enough to the actual header guard
> macro (i.e. likely misspelling), the #define is object-like with empty
> definition (I've followed what clang implements) and the macro isn't defined
> later on (at least not on the final #endif at the end of a header).
>
> In this case it emits a warning, so that
> #ifndef STDIO_H
> #define STDOI_H
> ...
> #endif
> or similar misspellings can be caught.
>
> clang enables this warning by default, but I've put it into -Wall instead
> as it still seems to be a style warning, nothing more severe; if a header
> doesn't survive multiple inclusion because of the misspelling, users will
> get different diagnostics.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
Thanks for this patch! I can't approve it myself, but I hope someone
who can does so soon! It looks fine to me, for whatever that's worth!
> 2024-09-11 Jakub Jelinek <ja...@redhat.com>
>
> PR preprocessor/96842
> libcpp/
> * include/cpplib.h (struct cpp_options): Add warn_header_guard member.
> (enum cpp_warning_reason): Add CPP_W_HEADER_GUARD enumerator.
> * internal.h (struct cpp_reader): Add mi_def_cmacro, mi_loc and
> mi_def_loc members.
> (_cpp_defined_macro_p): Constify type pointed by argument type.
> Formatting fix.
> * init.cc (cpp_create_reader): Clear
> CPP_OPTION (pfile, warn_header_guard).
> * directives.cc (struct if_stack): Add def_loc and mi_def_cmacro
> members.
> (DIRECTIVE_TABLE): Add IF_COND flag to define.
> (do_define): Set ifs->mi_def_cmacro on a define immediately following
> #ifndef directive for the guard. Clear pfile->mi_valid. Formatting
> fix.
> (do_endif): Copy over pfile->mi_def_cmacro and pfile->mi_def_loc
> if ifs->mi_def_cmacro is set and pfile->mi_cmacro isn't a defined
> macro.
> (push_conditional): Clear mi_def_cmacro and mi_def_loc members.
> * files.cc (_cpp_pop_file_buffer): Emit -Wheader-guard diagnostics.
> gcc/
> * doc/invoke.texi (Wheader-guard): Document.
> gcc/c-family/
> * c.opt (Wheader-guard): New option.
> * c.opt.urls: Regenerated.
> * c-ppoutput.cc (init_pp_output): Initialize also cb->get_suggestion.
> gcc/testsuite/
> * c-c++-common/cpp/Wheader-guard-1.c: New test.
> * c-c++-common/cpp/Wheader-guard-1-1.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-2.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-3.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-4.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-5.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-6.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-7.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-8.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-9.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-10.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-11.h: New test.
> * c-c++-common/cpp/Wheader-guard-1-12.h: New test.
> * c-c++-common/cpp/Wheader-guard-2.c: New test.
> * c-c++-common/cpp/Wheader-guard-2.h: New test.
> * c-c++-common/cpp/Wheader-guard-3.c: New test.
> * c-c++-common/cpp/Wheader-guard-3.h: New test.
>
> --- libcpp/include/cpplib.h.jj 2024-09-03 16:47:47.323031836 +0200
> +++ libcpp/include/cpplib.h 2024-09-11 16:39:36.373680969 +0200
> @@ -435,6 +435,10 @@ struct cpp_options
> /* Different -Wimplicit-fallthrough= levels. */
> unsigned char cpp_warn_implicit_fallthrough;
>
> + /* Nonzero means warn about a define of a different macro right after
> + #ifndef/#if !defined header guard directive. */
> + unsigned char warn_header_guard;
> +
> /* Nonzero means we should look for header.gcc files that remap file
> names. */
> unsigned char remap;
> @@ -702,7 +706,8 @@ enum cpp_warning_reason {
> CPP_W_EXPANSION_TO_DEFINED,
> CPP_W_BIDIRECTIONAL,
> CPP_W_INVALID_UTF8,
> - CPP_W_UNICODE
> + CPP_W_UNICODE,
> + CPP_W_HEADER_GUARD
> };
>
> /* Callback for header lookup for HEADER, which is the name of a
> --- libcpp/internal.h.jj 2024-09-03 16:47:47.324031823 +0200
> +++ libcpp/internal.h 2024-09-11 17:09:26.481097532 +0200
> @@ -493,9 +493,11 @@ struct cpp_reader
> been used. */
> bool seen_once_only;
>
> - /* Multiple include optimization. */
> + /* Multiple include optimization and -Wheader-guard warning. */
> const cpp_hashnode *mi_cmacro;
> const cpp_hashnode *mi_ind_cmacro;
> + const cpp_hashnode *mi_def_cmacro;
> + location_t mi_loc, mi_def_loc;
> bool mi_valid;
>
> /* Lexing. */
> @@ -676,7 +678,8 @@ _cpp_in_main_source_file (cpp_reader *pf
> }
>
> /* True if NODE is a macro for the purposes of ifdef, defined etc. */
> -inline bool _cpp_defined_macro_p (cpp_hashnode *node)
> +inline bool
> +_cpp_defined_macro_p (const cpp_hashnode *node)
> {
> /* Do not treat conditional macros as being defined. This is due to
> the powerpc port using conditional macros for 'vector', 'bool',
> --- libcpp/init.cc.jj 2024-09-03 16:47:47.323031836 +0200
> +++ libcpp/init.cc 2024-09-11 20:07:35.533395061 +0200
> @@ -228,6 +228,7 @@ cpp_create_reader (enum c_lang lang, cpp
> CPP_OPTION (pfile, warn_variadic_macros) = 1;
> CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
> CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
> + CPP_OPTION (pfile, warn_header_guard) = 0;
> /* By default, track locations of tokens resulting from macro
> expansion. The '2' means, track the locations with the highest
> accuracy. Read the comments for struct
> --- libcpp/directives.cc.jj 2024-09-03 16:47:47.299032147 +0200
> +++ libcpp/directives.cc 2024-09-11 18:52:42.000000000 +0200
> @@ -31,7 +31,10 @@ struct if_stack
> {
> struct if_stack *next;
> location_t line; /* Line where condition started. */
> - const cpp_hashnode *mi_cmacro;/* macro name for #ifndef around entire file
> */
> + location_t def_loc; /* Locus of following #define if any. */
> + const cpp_hashnode *mi_cmacro;/* Macro name for #ifndef around entire
> + file. */
> + const cpp_hashnode *mi_def_cmacro; /* Macro name in following #define. */
> bool skip_elses; /* Can future #else / #elif be skipped? */
> bool was_skipping; /* If were skipping on entry. */
> int type; /* Most recent conditional for diagnostics.
> */
> @@ -144,7 +147,7 @@ static void cpp_pop_definition (cpp_read
> where the extension appears to have come from. */
>
> #define DIRECTIVE_TABLE
> \
> - D(define, T_DEFINE = 0, KANDR, IN_I) \
> + D(define, T_DEFINE = 0, KANDR, IN_I | IF_COND) \
> D(include, T_INCLUDE, KANDR, INCL | EXPAND) \
> D(endif, T_ENDIF, KANDR, COND) \
> D(ifdef, T_IFDEF, KANDR, COND | IF_COND) \
> @@ -661,8 +664,8 @@ do_define (cpp_reader *pfile)
>
> /* If we have been requested to expand comments into macros,
> then re-enable saving of comments. */
> - pfile->state.save_comments =
> - ! CPP_OPTION (pfile, discard_comments_in_macro_exp);
> + pfile->state.save_comments
> + = ! CPP_OPTION (pfile, discard_comments_in_macro_exp);
>
> if (pfile->cb.before_define)
> pfile->cb.before_define (pfile);
> @@ -672,7 +675,28 @@ do_define (cpp_reader *pfile)
> pfile->cb.define (pfile, pfile->directive_line, node);
>
> node->flags &= ~NODE_USED;
> +
> + if (pfile->mi_valid
> + && !pfile->mi_cmacro
> + && CPP_OPTION (pfile, warn_header_guard)
> + && node->type == NT_USER_MACRO
> + && node->value.macro
> + && node->value.macro->count == 0
> + && !node->value.macro->fun_like)
> + {
> + cpp_buffer *buffer = pfile->buffer;
> + struct if_stack *ifs = buffer->if_stack;
> + if (ifs
> + && !ifs->next
> + && ifs->mi_cmacro
> + && node != ifs->mi_cmacro)
> + {
> + ifs->mi_def_cmacro = node;
> + ifs->def_loc = pfile->directive_line;
> + }
> + }
> }
> + pfile->mi_valid = false;
> }
>
> /* Handle #undef. Mark the identifier NT_VOID in the hash table. */
> @@ -2251,6 +2275,13 @@ do_endif (cpp_reader *pfile)
> {
> pfile->mi_valid = true;
> pfile->mi_cmacro = ifs->mi_cmacro;
> + pfile->mi_loc = ifs->line;
> + pfile->mi_def_cmacro = NULL;
> + if (ifs->mi_def_cmacro && !_cpp_defined_macro_p (pfile->mi_cmacro))
> + {
> + pfile->mi_def_cmacro = ifs->mi_def_cmacro;
> + pfile->mi_def_loc = ifs->def_loc;
> + }
> }
>
> buffer->if_stack = ifs->next;
> @@ -2272,6 +2303,7 @@ push_conditional (cpp_reader *pfile, int
>
> ifs = XOBNEW (&pfile->buffer_ob, struct if_stack);
> ifs->line = pfile->directive_line;
> + ifs->def_loc = 0;
> ifs->next = buffer->if_stack;
> ifs->skip_elses = pfile->state.skipping || !skip;
> ifs->was_skipping = pfile->state.skipping;
> @@ -2281,6 +2313,7 @@ push_conditional (cpp_reader *pfile, int
> ifs->mi_cmacro = cmacro;
> else
> ifs->mi_cmacro = 0;
> + ifs->mi_def_cmacro = 0;
>
> pfile->state.skipping = skip;
> buffer->if_stack = ifs;
> --- libcpp/files.cc.jj 2024-09-03 16:47:47.322031849 +0200
> +++ libcpp/files.cc 2024-09-11 19:32:43.754868132 +0200
> @@ -1664,7 +1664,28 @@ _cpp_pop_file_buffer (cpp_reader *pfile,
> /* Record the inclusion-preventing macro, which could be NULL
> meaning no controlling macro. */
> if (pfile->mi_valid && file->cmacro == NULL)
> - file->cmacro = pfile->mi_cmacro;
> + {
> + file->cmacro = pfile->mi_cmacro;
> + if (pfile->mi_cmacro
> + && pfile->mi_def_cmacro
> + && pfile->cb.get_suggestion)
> + {
> + const char *names[]
> + = { (const char *) NODE_NAME (pfile->mi_def_cmacro), NULL };
> + if (pfile->cb.get_suggestion (pfile,
> + (const char *)
> + NODE_NAME (pfile->mi_cmacro), names)
> + && cpp_warning_with_line (pfile, CPP_W_HEADER_GUARD,
> + pfile->mi_loc, 0,
> + "header guard \"%s\" followed by "
> + "\"#define\" of a different macro",
> + NODE_NAME (pfile->mi_cmacro)))
> + cpp_error_at (pfile, CPP_DL_NOTE, pfile->mi_def_loc,
> + "\"%s\" is defined here; did you mean \"%s\"?",
> + NODE_NAME (pfile->mi_def_cmacro),
> + NODE_NAME (pfile->mi_cmacro));
> + }
> + }
>
> /* Invalidate control macros in the #including file. */
> pfile->mi_valid = false;
> --- gcc/doc/invoke.texi.jj 2024-09-09 09:27:38.841086571 +0200
> +++ gcc/doc/invoke.texi 2024-09-11 20:23:10.033730119 +0200
> @@ -371,7 +371,7 @@ Objective-C and Objective-C++ Dialects}.
> -Wformat-security -Wformat-signedness -Wformat-truncation=@var{n}
> -Wformat-y2k -Wframe-address
> -Wframe-larger-than=@var{byte-size} -Wno-free-nonheap-object
> --Wno-if-not-aligned -Wno-ignored-attributes
> +-Wheader-guard -Wno-if-not-aligned -Wno-ignored-attributes
> -Wignored-qualifiers -Wno-incompatible-pointer-types -Whardened
> -Wimplicit -Wimplicit-fallthrough -Wimplicit-fallthrough=@var{n}
> -Wno-implicit-function-declaration -Wno-implicit-int
> @@ -10096,6 +10096,19 @@ Do not warn if certain built-in macros a
> warnings for redefinition of @code{__TIMESTAMP__}, @code{__TIME__},
> @code{__DATE__}, @code{__FILE__}, and @code{__BASE_FILE__}.
>
> +@opindex Wheader-guard
> +@item -Wheader-guard
> +Warn if a valid preprocessor header multiple inclusion guard has
> +a @code{#define} directive right after @code{#ifndef} or @code{#if !defined}
> +directive for the multiple inclusion guard, which defines a different macro
> +from the guard macro with a similar name, the actual multiple inclusion guard
> +macro isn't defined at the corresponding @code{#ifndef} directive at the end
> +of the header, and the @code{#define} directive defines object-like macro
> with
> +empty definition. In such case, it often is just misspelled guard name,
> +either in the @code{#ifndef} or @code{#if !defined} directive or in the
> +subsequent @code{#define} directive. This warning is enabled
> +by @option{-Wall}.
> +
> @opindex Wstrict-prototypes
> @opindex Wno-strict-prototypes
> @item -Wstrict-prototypes @r{(C and Objective-C only)}
> --- gcc/c-family/c.opt.jj 2024-09-03 16:47:47.185033625 +0200
> +++ gcc/c-family/c.opt 2024-09-11 20:07:15.786662712 +0200
> @@ -814,6 +814,10 @@ Wglobal-module
> C++ ObjC++ Var(warn_global_module) Warning Init(1)
> Warn about the global module fragment not containing only preprocessing
> directives.
>
> +Wheader-guard
> +C ObjC C++ ObjC++ CPP(warn_header_guard) CppReason(CPP_W_HEADER_GUARD)
> Var(cpp_warn_header_guard) Init(0) Warning LangEnabledBy(C ObjC C++
> ObjC++,Wall)
> +Warn when #ifndef of a header guard is followed by #define of a different
> macro with the header guard macro not defined at the end of header.
> +
> Wif-not-aligned
> C ObjC C++ ObjC++ Var(warn_if_not_aligned) Init(1) Warning
> Warn when the field in a struct is not aligned.
> --- gcc/c-family/c.opt.urls.jj 2024-08-14 18:19:28.731129432 +0200
> +++ gcc/c-family/c.opt.urls 2024-09-11 20:24:22.262751351 +0200
> @@ -412,6 +412,9 @@ UrlSuffix(gcc/Warning-Options.html#index
> Wglobal-module
> UrlSuffix(gcc/C_002b_002b-Dialect-Options.html#index-Wglobal-module)
>
> +Wheader-guard
> +UrlSuffix(gcc/Warning-Options.html#index-Wheader-guard)
> +
> Wif-not-aligned
> UrlSuffix(gcc/Warning-Options.html#index-Wif-not-aligned)
>
> --- gcc/c-family/c-ppoutput.cc.jj 2024-08-05 13:04:53.489121581 +0200
> +++ gcc/c-family/c-ppoutput.cc 2024-09-11 20:02:06.500854915 +0200
> @@ -164,6 +164,7 @@ init_pp_output (FILE *out_stream)
> cb->has_builtin = c_common_has_builtin;
> cb->has_feature = c_common_has_feature;
> cb->get_source_date_epoch = cb_get_source_date_epoch;
> + cb->get_suggestion = cb_get_suggestion;
> cb->remap_filename = remap_macro_filename;
>
> /* Initialize the print structure. */
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1.c.jj 2024-09-11
> 19:26:43.967778739 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1.c 2024-09-11
> 19:26:20.772095324 +0200
> @@ -0,0 +1,18 @@
> +/* PR preprocessor/96842 */
> +/* { dg-do preprocess } */
> +
> +#include "Wheader-guard-1-1.h"
> +#include "Wheader-guard-1-2.h"
> +#include "Wheader-guard-1-3.h"
> +#include "Wheader-guard-1-4.h"
> +#include "Wheader-guard-1-5.h"
> +#include "Wheader-guard-1-6.h"
> +#include "Wheader-guard-1-7.h"
> +#define WHEADER_GUARD_8
> +#include "Wheader-guard-1-8.h"
> +#include "Wheader-guard-1-9.h"
> +#include "Wheader-guard-1-10.h"
> +#include "Wheader-guard-1-11.h"
> +#include "Wheader-guard-1-12.h"
> +
> +int i;
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-1.h.jj 2024-09-11
> 19:26:39.912834079 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-1.h 2024-09-11
> 19:02:02.414054285 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_1
> +#define WHEADER_GUARD_1
> +/* This is how header guards should look like. */
> +#define SOMETHING1 123
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-2.h.jj 2024-09-11
> 19:26:39.914834052 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-2.h 2024-09-11
> 19:11:14.876484333 +0200
> @@ -0,0 +1,4 @@
> +#ifndef WHEADER_GUARD_2
> +#define WHEADERGUARD2 1
> +/* Don't warn if the different macro defines some tokens. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-3.h.jj 2024-09-11
> 19:26:39.915834039 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-3.h 2024-09-11
> 19:11:23.834361776 +0200
> @@ -0,0 +1,4 @@
> +#ifndef WHEADER_GUARD_3
> +#define WHEADERGUARD3()
> +/* Won't warn if it is a function-like macro. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-4.h.jj 2024-09-11
> 19:26:39.918833998 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-4.h 2024-09-11
> 19:04:18.569185598 +0200
> @@ -0,0 +1,3 @@
> +#ifndef WHEADER_GUARD_4
> +/* Don't warn if there is no define after #ifndef. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-5.h.jj 2024-09-11
> 19:26:39.919833984 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-5.h 2024-09-11
> 19:11:46.934045743 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_5
> +int guard5;
> +#define WHEADERGUARD5
> +/* Don't warn if there are tokens in between #ifndef and #define. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-6.h.jj 2024-09-11
> 19:26:39.921833957 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-6.h 2024-09-11
> 19:11:59.357875762 +0200
> @@ -0,0 +1,8 @@
> +#ifndef WHEADER_GUARD_6
> +#define WHEADERGUARD6
> +/* Don't warn if WHEADER_GUARD_6 is eventually defined later. */
> +#if 0
> +#else
> +#define WHEADER_GUARD_6
> +#endif
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-7.h.jj 2024-09-11
> 19:26:39.923833930 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-7.h 2024-09-11
> 19:22:21.860358981 +0200
> @@ -0,0 +1,4 @@
> +#ifndef WHEADER_GUARD_7
> +#define SOMETHING7
> +/* Don't warn if the two macros don't have similar names. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-8.h.jj 2024-09-11
> 19:26:39.925833903 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-8.h 2024-09-11
> 19:23:13.884647219 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_8
> +#define WHEADERGUARD8
> +/* Don't warn if the guard macro is already defined before
> + including the header. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-9.h.jj 2024-09-11
> 19:26:39.926833889 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-9.h 2024-09-11
> 19:24:34.647543778 +0200
> @@ -0,0 +1,5 @@
> +int guard9;
> +#ifndef WHEADER_GUARD_9
> +#define WHEADERGUARD9
> +/* Don't warn if it actually isn't a valid header guard. */
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-10.h.jj 2024-09-11
> 19:26:39.928833862 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-10.h 2024-09-11
> 19:25:02.012170293 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_10
> +#define WHEADERGUARD10
> +/* Don't warn if it actually isn't a valid header guard. */
> +#else
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-11.h.jj 2024-09-11
> 19:26:39.930833835 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-11.h 2024-09-11
> 19:25:30.972775022 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_11
> +#define WHEADERGUARD11
> +/* Don't warn if it actually isn't a valid header guard. */
> +#elif 1
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-12.h.jj 2024-09-11
> 19:26:39.932833808 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-1-12.h 2024-09-11
> 19:25:56.790422645 +0200
> @@ -0,0 +1,5 @@
> +#ifndef WHEADER_GUARD_12
> +#define WHEADERGUARD12
> +/* Don't warn if it actually isn't a valid header guard. */
> +#endif
> +#define ASOMETHING12
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-2.c.jj 2024-09-11
> 19:28:02.611705351 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-2.c 2024-09-11
> 20:12:47.124171614 +0200
> @@ -0,0 +1,10 @@
> +/* PR preprocessor/96842 */
> +/* { dg-do preprocess } */
> +/* { dg-options "-Wheader-guard" } */
> +
> +#include "Wheader-guard-2.h"
> +
> +int i;
> +
> +/* { dg-warning "header guard \"WHEADER_GUARD_2\" followed by \"#define\" of
> a different macro" "" { target *-*-* } 0 } */
> +/* { dg-message "\"WHEADERGUARD2\" is defined here; did you mean
> \"WHEADER_GUARD_2\"\\\?" "" { target *-*-* } 0 } */
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-2.h.jj 2024-09-11
> 19:28:45.893114621 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-2.h 2024-09-11
> 19:28:40.376189917 +0200
> @@ -0,0 +1,4 @@
> +#ifndef WHEADER_GUARD_2
> +#define WHEADERGUARD2
> +#define SOMETHING2 123
> +#endif
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-3.c.jj 2024-09-11
> 19:29:52.333207805 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-3.c 2024-09-11
> 20:13:17.867754901 +0200
> @@ -0,0 +1,10 @@
> +/* PR preprocessor/96842 */
> +/* { dg-do preprocess } */
> +/* { dg-options "-Wall" } */
> +
> +#include "Wheader-guard-3.h"
> +
> +int i;
> +
> +/* { dg-warning "header guard \"WHEADER_GUARD_3\" followed by \"#define\" of
> a different macro" "" { target *-*-* } 0 } */
> +/* { dg-message "\"WHEADERGUARD3\" is defined here; did you mean
> \"WHEADER_GUARD_3\"\\\?" "" { target *-*-* } 0 } */
> --- gcc/testsuite/c-c++-common/cpp/Wheader-guard-3.h.jj 2024-09-11
> 19:30:09.454974114 +0200
> +++ gcc/testsuite/c-c++-common/cpp/Wheader-guard-3.h 2024-09-11
> 19:30:23.562781561 +0200
> @@ -0,0 +1,4 @@
> +#if !defined(WHEADER_GUARD_3)
> +#define WHEADERGUARD3
> +#define SOMETHING3 123
> +#endif
>
> Jakub
>
