kc3-lang/automake/t/am-prog-cc-c-o.sh
-
Show log
Commit
-
Hash : e90126cf
Author :
Date : 2013-05-15T10:14:46
AM_PROG_CC_C_O: don't rely on AC_PROG_CC_C_O, re-implement similar logic ** Theoretical problems of AC_PROG_CC_C_O: Both cc and $CC are checked to see if they support the '-c' and '-o' options together. This behaviour is highly inconsistent with that of the other macros related to C compiler checks -- which test only $CC. It can also cause unwarranted uses of the 'compile' script on systems where the default 'cc' is inferior, but the user is compiling with a proper, different compiler (e.g., gcc). ** Practical problems with our previous implementation of C support m4 macros in Automake: - AM_PROG_AR must now be called *before* AC_PROG_CC; this wasn't the case before, and it turns out there are packages in the wild that relied on the old behaviour. - The cross-referenced requirements and macro rewrites juggled among AC_PROG_CC, AC_PROG_CC_C_O and AM_PROG_CC_C_O caused warnings in autoconf; for example, in our test 't/libobj3.sh', we could see warnings like these (here slightly tweaked for legibility): configure.ac:5: AC_REQUIRE: `AC_PROG_CC' expanded before required autoconf/c.m4:567: AC_PROG_CC_C_O is expanded from... autoconf/c.m4:429: AC_LANG_COMPILER(C) is expanded from... autoconf/lang.m4:329: AC_LANG_COMPILER_REQUIRE is expanded from... autoconf/general.m4:2606: AC_COMPILE_IFELSE is expanded from... m4sugar/m4sh.m4:639: AS_IF is expanded from... autoconf/general.m4:2031: AC_CACHE_VAL is expanded from... autoconf/general.m4:2052: AC_CACHE_CHECK is expanded from... aclocal.m4:70: AM_PROG_AR is expanded from... configure.ac:5: the top level ** Fix all of that: We fix all of the described issues with a new internal m4 macro _AM_PROG_CC_C_O (inspired to, but not based on, AC_PROG_CC_C_O) that gets tacked on to AC_PROG_CC automatically (this is done in the Automake-generated aclocal.m4) and that takes care of checking and adjusting '$CC' for "-c -o" support. The macro AM_PROG_CC_C_O is still present, but is now just a thin wrapper around such Automake-enhanced AC_PROG_CC. It is worth noting that the present patch causes three slight *backward-incompatibilities*: 1. The name cache variable used by AM_PROG_CC_C_O is no longer computed (at configure runtime!) from the content of '$CC', but is statically defined as 'am_cv_prog_cc_c_o'. 2. 'cc' is no longer checked by AM_PROG_CC_C_O, only '$CC' is. 3. AM_PROG_CC_C_O no longer AC_DEFINE the C preprocessor symbol 'NO_MINUS_C_MINUS_O'. Given however that the third change can easily be worked around, that the first two changes can be legitimately seen as bug fixes, and that the new semantics introduced by such changes will simplify the transition to Automake 2.0 (when the 'subdir-objects' will always be enabled unconditionally), we believe they are acceptable to be shipped with Automake 1.14. With this patch, we also revert some of the testsuite adjustments done in previous commit v1.13.2-178-g9877109 of 2013-05-24 (compile: rewrite AC_PROG_CC with AM_PROG_CC_C_O contents). Such adjustments are no longer needed. * m4/minuso.m4 (_AM_PROG_CC_C_O): New internal macro, basically and adjusted version of a merge between Autoconf-provided AC_PROG_CC_C_O and our old implementation of AM_PROG_CC_C_O. (AM_PROG_CC_C_O): Redefine as a simple wrapper around AC_PROG_CC. * m4/init.m4 (AC_PROG_CC): Append _AM_PROG_CC_C_O, not AM_PROG_CC_C_O, to the pre-existing expansion of this macro. * m4/ar-lib.m4 (AM_PROG_AR): No longer require it to be expanded after AC_PROG_CC. * t/aclocal-deps.sh: Move AC_PROG_CC invocation after AC_PROG_RANLIB and AM_PROG_AR invocations. Things should work this way too (as they used to). * t/subobj-clean-lt-pr10697.sh: Likewise. * t/alloca.sh: Move AC_PROG_CC invocation after AM_PROG_AR invocation. * t/condlib.sh: Likewise. * t/aclocal-deps.sh: Move AC_PROG_CC invocation after LT_INIT and AM_PROG_AR invocations. Make autoconf and autoheader warnings fatal. * t/am-prog-cc-c-o.sh: Adjust to the new semantics, enhance a little, and reduce code duplication. * t/ccnoco.sh: Make autoconf warnings fatal. * t/subpkg.sh: Likewise. * t/ccnoco-lib.sh: Likewise, and fix a comment. * t/link_cond.sh: Enhance a couple of error messages. * configure.ac: Drop "nullification" of AM_PROG_CC_C_O. * NEWS: Adjust. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>
-
t/am-prog-cc-c-o.sh
-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126
#! /bin/sh # Copyright (C) 2013 Free Software Foundation, Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2, or (at your option) # any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # Check that uses of the obsolescent AM_PROG_CC_C_O macro doesn't # cause spurious warnings or errors. Suggested by Eric Blake. # We need gcc for for two reasons: # 1. to ensure our C compiler grasps "-c -o" together. # 2. to be able to later fake a dumb compiler not grasping that # (done with 'cc-no-c-o' script below, which required gcc). required=gcc . test-init.sh echo bin_PROGRAMS = foo > Makefile.am echo 'int main (void) { return 0; }' > foo.c cp configure.ac configure.bak cat > acinclude.m4 <<'END' AC_DEFUN([AM_TWEAKED_OUTPUT], [ # For debugging. printf "CC = '%s'\\n" "$CC" # Make sure that $CC can be used after AM_PROG_CC_C_O. $CC --version || exit 1 $CC -v || exit 1 # $CC rewrite should only take place on time. case " $CC " in *" compile"*" compile"*) AC_MSG_ERROR([CC rewritten twice]);; esac AC_OUTPUT ]) END # --- cat configure.bak - > configure.ac << 'END' dnl It's OK to call AM_PROG_CC_C_O after AC_PROG_CC. AC_PROG_CC AM_PROG_CC_C_O AM_TWEAKED_OUTPUT END $ACLOCAL $AUTOCONF $AUTOMAKE --add-missing ./configure >stdout || { cat stdout; exit 1; } cat stdout if test "$AM_TESTSUITE_SIMULATING_NO_CC_C_O" != no; then $EGREP 'understands? -c and -o together.* no$' stdout else $EGREP 'understands? -c and -o together.* yes$' stdout fi # No repeated checks please. test $(grep -c ".*-c['\" ].*-o['\" ]" stdout) -eq 1 $MAKE $MAKE maintainer-clean rm -rf autom4te*.cache # --- cat configure.bak - > configure.ac << 'END' dnl It's also OK to call AM_PROG_CC_C_O *before* AC_PROG_CC. AM_PROG_CC_C_O AC_PROG_CC AM_TWEAKED_OUTPUT END $ACLOCAL $AUTOCONF $AUTOMAKE --add-missing ./configure >stdout || { cat stdout; exit 1; } cat stdout if test "$AM_TESTSUITE_SIMULATING_NO_CC_C_O" != no; then $EGREP 'understands? -c and -o together.* no$' stdout else $EGREP 'understands? -c and -o together.* yes$' stdout fi # Repeated checks are OK in this case, but should be cached. test $(grep ".*-c['\" ].*-o['\" ]" stdout \ | $FGREP -v ' (cached) ' | wc -l) -eq 1 $MAKE $MAKE maintainer-clean rm -rf autom4te*.cache # --- cat configure.bak - > configure.ac << 'END' dnl It's also OK to call AM_PROG_CC_C_O *without* AC_PROG_CC. AM_PROG_CC_C_O AM_TWEAKED_OUTPUT END $ACLOCAL $AUTOCONF $AUTOMAKE --add-missing # Make sure the compiler doesn't understand '-c -o' CC=$am_testaux_builddir/cc-no-c-o; export CC ./configure >stdout || { cat stdout; exit 1; } cat stdout $EGREP 'understands? -c and -o together.* no$' stdout # No repeated checks please. test $(grep -c ".*-c['\" ].*-o['\" ]" stdout) -eq 1 $MAKE :