From patchwork Thu Jun 23 17:30:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddhesh Poyarekar X-Patchwork-Id: 13339 Received: (qmail 10542 invoked by alias); 23 Jun 2016 17:30:46 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 10531 invoked by uid 89); 23 Jun 2016 17:30:45 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_WEB, SPF_NEUTRAL autolearn=no version=3.3.2 spammy=H*F:U*siddhesh, HX-Envelope-From:sk:siddhes X-HELO: homiemail-a91.g.dreamhost.com From: Siddhesh Poyarekar To: libc-alpha@sourceware.org Subject: [PATCH] Avoid attempt for runtime checks if all environments are defined Date: Thu, 23 Jun 2016 23:00:10 +0530 Message-Id: <1466703010-10670-1-git-send-email-siddhesh@sourceware.org> getconf has the capability to do a runtime check for environment support in cases where there is optional support for an environment (_POSIX_V7_ILP32_OFF32 on x86_64 for example) and this is indicated by not defining the _POSIX_V7_ILP32_OFF32 macro, which results in getconf doing an additional execve of _POSIX_V7_ILP32_OFF32 in the $GETCONF_DIR. The default bits/environments.h however does not leave any environment macros undefined, which means that no such additiona execve is needed. gcc trunk catches this as a build failure since it finds that the code block inside switch(specs[i].num) is not reachable. Avoid this error by not bothering about the additional exec (and looking in specific environments) when all environments are defined. Tested on aarch64. * posix/getconf.c: Define ALL_ENVIRONMENTS_DEFINED if all environment macros are defined. (main): Avoid execve if ALL_ENVIRONMENTS_DEFINED is defined. --- posix/getconf.c | 84 ++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 60 insertions(+), 24 deletions(-) diff --git a/posix/getconf.c b/posix/getconf.c index 3e03396..7880446 100644 --- a/posix/getconf.c +++ b/posix/getconf.c @@ -29,6 +29,23 @@ #define NEED_SPEC_ARRAY 1 #include +/* If all of the environments are defined in environments.h, then we don't need + to bother with doing a runtime check for a specific environment. */ +#if (defined _SC_V6_ILP32_OFF32 \ + && defined _SC_V7_LPBIG_OFFBIG \ + && defined _SC_XBS5_LP64_OFF64 \ + && defined _SC_V6_LP64_OFF64 \ + && defined _SC_V7_ILP32_OFFBIG \ + && defined _SC_V6_LPBIG_OFFBIG \ + && defined _SC_V7_LP64_OFF64 \ + && defined _SC_V7_ILP32_OFF32 \ + && defined _SC_XBS5_LPBIG_OFFBIG \ + && defined _SC_XBS5_ILP32_OFFBIG \ + && defined _SC_V6_ILP32_OFFBIG \ + && defined _SC_XBS5_ILP32_OFF32) + #define ALL_ENVIRONMENTS_DEFINED 1 +#endif + struct conf { const char *name; @@ -488,6 +505,24 @@ environment SPEC.\n\n")); return 0; } +#ifdef ALL_ENVIRONMENTS_DEFINED + if (argc > 1 && strncmp (argv[1], "-v", 2) == 0) + { + if (argv[1][2] == '\0') + { + if (argc < 3) + usage (); + + argv += 2; + argc -= 2; + } + else + { + argv += 1; + argc += 1; + } + } +#else const char *getconf_dir = getenv ("GETCONF_DIR") ?: GETCONF_DIR; size_t getconf_dirlen = strlen (getconf_dir); @@ -538,42 +573,42 @@ environment SPEC.\n\n")); switch (specs[i].num) { -#ifndef _XBS5_ILP32_OFF32 +# ifndef _XBS5_ILP32_OFF32 case _SC_XBS5_ILP32_OFF32: -#endif -#ifndef _XBS5_ILP32_OFFBIG +# endif +# ifndef _XBS5_ILP32_OFFBIG case _SC_XBS5_ILP32_OFFBIG: -#endif -#ifndef _XBS5_LP64_OFF64 +# endif +# ifndef _XBS5_LP64_OFF64 case _SC_XBS5_LP64_OFF64: -#endif -#ifndef _XBS5_LPBIG_OFFBIG +# endif +# ifndef _XBS5_LPBIG_OFFBIG case _SC_XBS5_LPBIG_OFFBIG: -#endif -#ifndef _POSIX_V6_ILP32_OFF32 +# endif +# ifndef _POSIX_V6_ILP32_OFF32 case _SC_V6_ILP32_OFF32: -#endif -#ifndef _POSIX_V6_ILP32_OFFBIG +# endif +# ifndef _POSIX_V6_ILP32_OFFBIG case _SC_V6_ILP32_OFFBIG: -#endif -#ifndef _POSIX_V6_LP64_OFF64 +# endif +# ifndef _POSIX_V6_LP64_OFF64 case _SC_V6_LP64_OFF64: -#endif -#ifndef _POSIX_V6_LPBIG_OFFBIG +# endif +# ifndef _POSIX_V6_LPBIG_OFFBIG case _SC_V6_LPBIG_OFFBIG: -#endif -#ifndef _POSIX_V7_ILP32_OFF32 +# endif +# ifndef _POSIX_V7_ILP32_OFF32 case _SC_V7_ILP32_OFF32: -#endif -#ifndef _POSIX_V7_ILP32_OFFBIG +# endif +# ifndef _POSIX_V7_ILP32_OFFBIG case _SC_V7_ILP32_OFFBIG: -#endif -#ifndef _POSIX_V7_LP64_OFF64 +# endif +# ifndef _POSIX_V7_LP64_OFF64 case _SC_V7_LP64_OFF64: -#endif -#ifndef _POSIX_V7_LPBIG_OFFBIG +# endif +# ifndef _POSIX_V7_LPBIG_OFFBIG case _SC_V7_LPBIG_OFFBIG: -#endif +# endif { const char *args[argc + 3]; size_t spec_len = strlen (spec); @@ -592,6 +627,7 @@ environment SPEC.\n\n")); break; } } +#endif if (argc > 1 && strcmp (argv[1], "-a") == 0) {