From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30339 invoked by alias); 30 Sep 2002 01:07:07 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 30309 invoked from network); 30 Sep 2002 01:07:05 -0000 Received: from unknown (HELO hiauly1.hia.nrc.ca) (132.246.100.193) by sources.redhat.com with SMTP; 30 Sep 2002 01:07:05 -0000 Received: from hiauly1.hia.nrc.ca (localhost [127.0.0.1]) by hiauly1.hia.nrc.ca (8.12.0.Beta16/8.12.0.Beta16) with ESMTP id g8U16v00021329; Sun, 29 Sep 2002 21:06:57 -0400 (EDT) Received: (from dave@localhost) by hiauly1.hia.nrc.ca (8.12.0.Beta16/8.12.0.Beta16) id g8U16upQ021328; Sun, 29 Sep 2002 21:06:56 -0400 (EDT) Message-Id: <200209300106.g8U16upQ021328@hiauly1.hia.nrc.ca> Subject: Re: Backport 'cpp include directory search order warning' patch to 3.2.1? To: zack@codesourcery.com (Zack Weinberg) Date: Sun, 29 Sep 2002 19:09:00 -0000 From: "John David Anglin" Cc: gcc@gcc.gnu.org, mark@codesourcery.com, neil@daikokuya.co.uk In-Reply-To: <20020930005402.GA21072@codesourcery.com> from "Zack Weinberg" at Sep 29, 2002 05:54:02 pm MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SW-Source: 2002-09/txt/msg01231.txt.bz2 > I'd like to propose John's patch to squelch the 'cpp: changing search > order...' warnings be backported to 3.2.1. The warnings can be > considered a regression from 3.0, and cause autoconf scripts to break, > which makes them more than just a nuisance. If this is okay with the > release manager, I'll do the legwork. The last version of the patch that I had for 3.2.1 is below. Dave -- J. David Anglin dave.anglin@nrc.ca National Research Council of Canada (613) 990-0752 (FAX: 952-6605) Index: cppinit.c =================================================================== RCS file: /cvsroot/gcc/gcc/gcc/cppinit.c,v retrieving revision 1.202.2.5.2.2 diff -u -3 -p -r1.202.2.5.2.2 cppinit.c --- cppinit.c 18 Aug 2002 06:24:13 -0000 1.202.2.5.2.2 +++ cppinit.c 21 Aug 2002 16:29:31 -0000 @@ -103,9 +103,13 @@ static void mark_named_operators PARAMS static void append_include_chain PARAMS ((cpp_reader *, char *, int, int)); static struct search_path * remove_dup_dir PARAMS ((cpp_reader *, + struct search_path *, + struct search_path **)); +static struct search_path * remove_dup_nonsys_dirs PARAMS ((cpp_reader *, + struct search_path **, struct search_path *)); static struct search_path * remove_dup_dirs PARAMS ((cpp_reader *, - struct search_path *)); + struct search_path **)); static void merge_include_chains PARAMS ((cpp_reader *)); static bool push_include PARAMS ((cpp_reader *, struct pending_option *)); @@ -272,55 +276,98 @@ append_include_chain (pfile, dir, path, } /* Handle a duplicated include path. PREV is the link in the chain - before the duplicate. The duplicate is removed from the chain and - freed. Returns PREV. */ + before the duplicate, or NULL if the duplicate is at the head of + the chain. The duplicate is removed from the chain and freed. + Returns PREV. */ static struct search_path * -remove_dup_dir (pfile, prev) +remove_dup_dir (pfile, prev, head_ptr) cpp_reader *pfile; struct search_path *prev; + struct search_path **head_ptr; { - struct search_path *cur = prev->next; + struct search_path *cur; + + if (prev != NULL) + { + cur = prev->next; + prev->next = cur->next; + } + else + { + cur = *head_ptr; + *head_ptr = cur->next; + } if (CPP_OPTION (pfile, verbose)) fprintf (stderr, _("ignoring duplicate directory \"%s\"\n"), cur->name); - prev->next = cur->next; free ((PTR) cur->name); free (cur); return prev; } +/* Remove duplicate non-system directories for which there is an equivalent + system directory latter in the chain. The range for removal is between + *HEAD_PTR and END. Returns the directory before END, or NULL if none. + This algorithm is quadratic in the number of system directories, which is + acceptable since there aren't usually that many of them. */ +static struct search_path * +remove_dup_nonsys_dirs (pfile, head_ptr, end) + cpp_reader *pfile; + struct search_path **head_ptr; + struct search_path *end; +{ + int sysdir = 0; + struct search_path *prev = NULL, *cur, *other; + + for (cur = *head_ptr; cur; cur = cur->next) + { + if (cur->sysp) + { + sysdir = 1; + for (other = *head_ptr, prev = NULL; + other != end; + other = other ? other->next : *head_ptr) + { + if (!other->sysp + && INO_T_EQ (cur->ino, other->ino) + && cur->dev == other->dev) + { + other = remove_dup_dir (pfile, prev, head_ptr); + if (CPP_OPTION (pfile, verbose)) + fprintf (stderr, + _(" as it is a non-system directory that duplicates a system directory\n")); + } + prev = other; + } + } + } + + if (!sysdir) + for (cur = *head_ptr; cur != end; cur = cur->next) + prev = cur; + + return prev; +} + /* Remove duplicate directories from a chain. Returns the tail of the chain, or NULL if the chain is empty. This algorithm is quadratic in the number of -I switches, which is acceptable since there aren't usually that many of them. */ static struct search_path * -remove_dup_dirs (pfile, head) +remove_dup_dirs (pfile, head_ptr) cpp_reader *pfile; - struct search_path *head; + struct search_path **head_ptr; { struct search_path *prev = NULL, *cur, *other; - for (cur = head; cur; cur = cur->next) + for (cur = *head_ptr; cur; cur = cur->next) { - for (other = head; other != cur; other = other->next) - if (INO_T_EQ (cur->ino, other->ino) && cur->dev == other->dev) + for (other = *head_ptr; other != cur; other = other->next) + if (INO_T_EQ (cur->ino, other->ino) && cur->dev == other->dev) { - if (cur->sysp && !other->sysp) - { - cpp_warning (pfile, - "changing search order for system directory \"%s\"", - cur->name); - if (strcmp (cur->name, other->name)) - cpp_warning (pfile, - " as it is the same as non-system directory \"%s\"", - other->name); - else - cpp_warning (pfile, - " as it has already been specified as a non-system directory"); - } - cur = remove_dup_dir (pfile, prev); + cur = remove_dup_dir (pfile, prev, head_ptr); break; } prev = cur; @@ -358,28 +405,33 @@ merge_include_chains (pfile) else brack = systm; - /* This is a bit tricky. First we drop dupes from the quote-include - list. Then we drop dupes from the bracket-include list. - Finally, if qtail and brack are the same directory, we cut out - brack and move brack up to point to qtail. + /* This is a bit tricky. First we drop non-system dupes of system + directories from the merged bracket-include list. Next we drop + dupes from the bracket and quote include lists. Then we drop + non-system dupes from the merged quote-include list. Finally, + if qtail and brack are the same directory, we cut out brack and + move brack up to point to qtail. We can't just merge the lists and then uniquify them because then we may lose directories from the <> search path that should - be there; consider -Ifoo -Ibar -I- -Ifoo -Iquux. It is however + be there; consider -Ifoo -Ibar -I- -Ifoo -Iquux. It is however safe to treat -Ibar -Ifoo -I- -Ifoo -Iquux as if written -Ibar -I- -Ifoo -Iquux. */ - remove_dup_dirs (pfile, brack); - qtail = remove_dup_dirs (pfile, quote); + remove_dup_nonsys_dirs (pfile, &brack, systm); + remove_dup_dirs (pfile, &brack); if (quote) { + qtail = remove_dup_dirs (pfile, "e); qtail->next = brack; + qtail = remove_dup_nonsys_dirs (pfile, "e, brack); + /* If brack == qtail, remove brack as it's simpler. */ - if (brack && INO_T_EQ (qtail->ino, brack->ino) + if (qtail && brack && INO_T_EQ (qtail->ino, brack->ino) && qtail->dev == brack->dev) - brack = remove_dup_dir (pfile, qtail); + brack = remove_dup_dir (pfile, qtail, "e); } else quote = brack; Index: doc/cpp.texi =================================================================== RCS file: /cvsroot/gcc/gcc/gcc/doc/cpp.texi,v retrieving revision 1.24.2.3.4.1 diff -u -3 -p -r1.24.2.3.4.1 cpp.texi --- doc/cpp.texi 15 Aug 2002 19:46:42 -0000 1.24.2.3.4.1 +++ doc/cpp.texi 21 Aug 2002 16:29:37 -0000 @@ -830,11 +830,22 @@ version of GCC in use. You can add to this list with the @option{-I@var{dir}} command line option. All the directories named by @option{-I} are searched, in -left-to-right order, @emph{before} the default directories. You can -also prevent GCC from searching any of the default directories with the -@option{-nostdinc} option. This is useful when you are compiling an +left-to-right order, @emph{before} the default directories. The only +exception is when @file{dir} is already searched by default. In +this case, the option is ignored and the search order for system +directories remains unchanged. + +Duplicate directories are removed from the quote and bracket search +chains before the two chains are merged to make the final search chain. +Thus, it is possible for a directory to occur twice in the final search +chain if it was specified in both the quote and bracket chains. + +You can prevent GCC from searching any of the default directories with +the @option{-nostdinc} option. This is useful when you are compiling an operating system kernel or some other program that does not use the standard C library facilities, or the standard C library itself. +@option{-I} options are not ignored as described above when +@option{-nostdinc} is in effect. GCC looks for headers requested with @code{@w{#include "@var{file}"}} first in the directory containing the current file, then in the same @@ -843,12 +854,6 @@ For example, if @file{/usr/include/sys/s @code{@w{#include "types.h"}}, GCC looks for @file{types.h} first in @file{/usr/include/sys}, then in its usual search path. -If you name a search directory with @option{-I@var{dir}} that is also a -system include directory, the @option{-I} wins; the directory will be -searched according to the @option{-I} ordering, and it will not be -treated as a system include directory. GCC will warn you when a system -include directory is hidden in this way. - @samp{#line} (@pxref{Line Control}) does not change GCC's idea of the directory containing the current file. @@ -1081,8 +1086,8 @@ found in that directory will be consider All directories named by @option{-isystem} are searched @emph{after} all directories named by @option{-I}, no matter what their order was on the command line. If the same directory is named by both @option{-I} and -@option{-isystem}, @option{-I} wins; it is as if the @option{-isystem} option -had never been specified at all. GCC warns you when this happens. +@option{-isystem}, the @option{-I} option is ignored. GCC provides an +informative message when this occurs if @option{-v} is used. @findex #pragma GCC system_header There is also a directive, @code{@w{#pragma GCC system_header}}, which @@ -1815,9 +1820,7 @@ conformance to the C Standard. GNU CPP processing system header files, but when processing user files @code{__STDC__} is always 1. This has been reported to cause problems; for instance, some versions of Solaris provide X Windows headers that -expect @code{__STDC__} to be either undefined or 1. You may be able to -work around this sort of problem by using an @option{-I} option to -cancel treatment of those headers as system headers. @xref{Invocation}. +expect @code{__STDC__} to be either undefined or 1. @xref{Invocation}. @item __STDC_VERSION__ This macro expands to the C Standard's version number, a long integer Index: doc/cppopts.texi =================================================================== RCS file: /cvsroot/gcc/gcc/gcc/doc/cppopts.texi,v retrieving revision 1.1.2.1 diff -u -3 -p -r1.1.2.1 cppopts.texi --- doc/cppopts.texi 11 Mar 2002 19:59:58 -0000 1.1.2.1 +++ doc/cppopts.texi 21 Aug 2002 16:29:37 -0000 @@ -51,16 +51,14 @@ for header files. @xref{Search Path}. @end ifset Directories named by @option{-I} are searched before the standard -system include directories. - -It is dangerous to specify a standard system include directory in an -@option{-I} option. This defeats the special treatment of system -headers +system include directories. If the directory @var{dir} is a standard +system include directory, the option is ignored to ensure that the +default search order for system directories and the special treatment +of system headers are not defeated @ifset cppmanual (@pxref{System Headers}) @end ifset -. It can also defeat the repairs to buggy system headers which GCC -makes when it is installed. +. @item -o @var{file} @opindex o Index: doc/install.texi =================================================================== RCS file: /cvsroot/gcc/gcc/gcc/doc/install.texi,v retrieving revision 1.92.2.29.2.3 diff -u -3 -p -r1.92.2.29.2.3 install.texi --- doc/install.texi 19 Aug 2002 17:00:21 -0000 1.92.2.29.2.3 +++ doc/install.texi 21 Aug 2002 16:29:45 -0000 @@ -460,6 +460,43 @@ any in that directory---are not part of programs---perhaps many others. (GCC installs its own header files in another directory which is based on the @option{--prefix} value.) +Both the local-prefix include directory and the GCC-prefix include +directory are part of GCC's "system include" directories. Although these +two directories are not fixed, they need to be searched in the proper +order for the correct processing of the include_next directive. The +local-prefix include directory is searched before the GCC-prefix +include directory. Another characteristic of system include directories +is that pedantic warnings are turned off for headers in these directories. + +Some autoconf macros add @option{-I @var{directory}} options to the +compiler command line, to ensure that directories containing installed +packages' headers are searched. When @var{directory} is one of GCC's +system include directories, GCC will ignore the option so that system +directories continue to be processed in the correct order. This +may result in a search order different from what was specified but the +directory will still be searched. + +GCC automatically searches for ordinary libraries using +@env{GCC_EXEC_PREFIX}. Thus, when the same installation prefix is +used for both GCC and packages, GCC will automatically search for +both headers and libraries. This provides a configuration that is +easy to use. GCC behaves in a manner similar to that when it is +installed as a system compiler in @file{/usr}. + +Sites that need to install multiple versions of GCC may not want to +use the above simple configuration. It is possible to use the +@option{--program-prefix}, @option{--program-suffix} and +@option{--program-transform-name} options to install multiple versions +into a single directory, but it may be simpler to use different prefixes +and the @option{--with-local-prefix} option to specify the location of the +site-specific files for each version. It will then be necessary for +users to specify explicitly the location of local site libraries +(e.g., with @env{LIBRARY_PATH}). + +The same value can be used for both @option{--with-local-prefix} and +@option{--prefix} provided it is not @file{/usr}. This can be used +to avoid the default search of @file{/usr/local/include}. + @strong{Do not} specify @file{/usr} as the @option{--with-local-prefix}! The directory you use for @option{--with-local-prefix} @strong{must not} contain any of the system's standard header files. If it did contain Index: doc/invoke.texi =================================================================== RCS file: /cvsroot/gcc/gcc/gcc/doc/invoke.texi,v retrieving revision 1.119.2.12.4.1 diff -u -3 -p -r1.119.2.12.4.1 invoke.texi --- doc/invoke.texi 20 Aug 2002 07:04:36 -0000 1.119.2.12.4.1 +++ doc/invoke.texi 21 Aug 2002 16:30:12 -0000 @@ -4200,15 +4200,13 @@ one @option{-I} option, the directories order; the standard system directories come after. If a standard system include directory, or a directory specified with -@option{-isystem}, is also specified with @option{-I}, it will be -searched only in the position requested by @option{-I}. Also, it will -not be considered a system include directory. If that directory really -does contain system headers, there is a good chance that they will -break. For instance, if GCC's installation procedure edited the headers -in @file{/usr/include} to fix bugs, @samp{-I/usr/include} will cause the -original, buggy headers to be found instead of the corrected ones. GCC -will issue a warning when a system include directory is hidden in this -way. +@option{-isystem}, is also specified with @option{-I}, the @option{-I} +option will be ignored. The directory will still be searched but as a +system directory at its normal position in the system include chain. +This is to ensure that GCC's procedure to fix buggy system headers and +the ordering for the include_next directive are not inadvertantly changed. +If you really need to change the search order for system directories, +use the @option{-nostdinc} and/or @option{-isystem} options. @item -I- @opindex I-