File: ax_check_vscript.m4

package info (click to toggle)
util-linux 2.34-0.1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 46,508 kB
  • sloc: ansic: 129,594; sh: 15,590; yacc: 1,170; makefile: 397; xml: 369; python: 316; csh: 37; sed: 16; perl: 15
file content (142 lines) | stat: -rw-r--r-- 4,716 bytes parent folder | download | duplicates (5)
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
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
# ===========================================================================
#     http://www.gnu.org/software/autoconf-archive/ax_check_vscript.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_CHECK_VSCRIPT
#
# DESCRIPTION
#
#   Check whether the linker supports version scripts.  Version scripts are
#   used when building shared libraries to bind symbols to version nodes
#   (helping to detect incompatibilities) or to limit the visibility of
#   non-public symbols.
#
#   Output:
#
#   If version scripts are supported, VSCRIPT_LDFLAGS will contain the
#   appropriate flag to pass to the linker.  On GNU systems this would
#   typically be "-Wl,--version-script", and on Solaris it would typically
#   be "-Wl,-M".
#
#   Two Automake conditionals are also set:
#
#    HAVE_VSCRIPT is true if the linker supports version scripts with
#    entries that use simple wildcards, like "local: *".
#
#    HAVE_VSCRIPT_COMPLEX is true if the linker supports version scripts with
#    pattern matching wildcards, like "global: Java_*".
#
#   On systems that do not support symbol versioning, such as Mac OS X, both
#   conditionals will be false.  They will also be false if the user passes
#   "--disable-symvers" on the configure command line.
#
#   Example:
#
#    configure.ac:
#
#     AX_CHECK_VSCRIPT
#
#    Makefile.am:
#
#     if HAVE_VSCRIPT
#     libfoo_la_LDFLAGS += $(VSCRIPT_LDFLAGS),@srcdir@/libfoo.map
#     endif
#
#     if HAVE_VSCRIPT_COMPLEX
#     libbar_la_LDFLAGS += $(VSCRIPT_LDFLAGS),@srcdir@/libbar.map
#     endif
#
# LICENSE
#
#   Copyright (c) 2014 Kevin Cernekee <cernekee@gmail.com>
#
#   Copying and distribution of this file, with or without modification, are
#   permitted in any medium without royalty provided the copyright notice
#   and this notice are preserved. This file is offered as-is, without any
#   warranty.

#serial 1

# _AX_CHECK_VSCRIPT(flag, global-sym, action-if-link-succeeds, [junk-file=no])
AC_DEFUN([_AX_CHECK_VSCRIPT], [
  AC_LANG_PUSH([C])
  ax_check_vscript_save_flags="$LDFLAGS"
  echo "V1 { global: $2; local: *; };" > conftest.map
  AS_IF([test x$4 = xyes], [
    echo "{" >> conftest.map
  ])
  LDFLAGS="$LDFLAGS -Wl,$1,conftest.map"
  AC_LINK_IFELSE([AC_LANG_PROGRAM([[int show, hide;]], [])], [$3])
  LDFLAGS="$ax_check_vscript_save_flags"
  rm -f conftest.map
  AC_LANG_POP([C])
]) dnl _AX_CHECK_VSCRIPT

AC_DEFUN([AX_CHECK_VSCRIPT], [

  AC_ARG_ENABLE([symvers],
    AS_HELP_STRING([--disable-symvers],
                   [disable library symbol versioning [default=auto]]),
    [want_symvers=$enableval],
    [want_symvers=yes]
  )

  AS_IF([test x$want_symvers = xyes], [

    dnl First test --version-script and -M with a simple wildcard.

    AC_CACHE_CHECK([linker version script flag], ax_cv_check_vscript_flag, [
      ax_cv_check_vscript_flag=unsupported
      _AX_CHECK_VSCRIPT([--version-script], [show], [
        ax_cv_check_vscript_flag=--version-script
      ])
      AS_IF([test x$ax_cv_check_vscript_flag = xunsupported], [
        _AX_CHECK_VSCRIPT([-M], [show], [ax_cv_check_vscript_flag=-M])
      ])

      dnl The linker may interpret -M (no argument) as "produce a load map."
      dnl If "-M conftest.map" doesn't fail when conftest.map contains
      dnl obvious syntax errors, assume this is the case.

      AS_IF([test x$ax_cv_check_vscript_flag != xunsupported], [
        _AX_CHECK_VSCRIPT([$ax_cv_check_vscript_flag], [show],
	                  [ax_cv_check_vscript_flag=unsupported], [yes])
      ])
    ])

    dnl If the simple wildcard worked, retest with a complex wildcard.

    AS_IF([test x$ax_cv_check_vscript_flag != xunsupported], [
      ax_check_vscript_flag=$ax_cv_check_vscript_flag
      AC_CACHE_CHECK([if version scripts can use complex wildcards],
                     ax_cv_check_vscript_complex_wildcards, [
        ax_cv_check_vscript_complex_wildcards=no
        _AX_CHECK_VSCRIPT([$ax_cv_check_vscript_flag], [sh*], [
        ax_cv_check_vscript_complex_wildcards=yes])
      ])
      ax_check_vscript_complex_wildcards="$ax_cv_check_vscript_complex_wildcards"
    ], [
      ax_check_vscript_flag=
      ax_check_vscript_complex_wildcards=no
    ])
  ], [
    AC_MSG_CHECKING([linker version script flag])
    AC_MSG_RESULT([disabled])

    ax_check_vscript_flag=
    ax_check_vscript_complex_wildcards=no
  ])

  AS_IF([test x$ax_check_vscript_flag != x], [
    VSCRIPT_LDFLAGS="-Wl,$ax_check_vscript_flag"
    AC_SUBST([VSCRIPT_LDFLAGS])
  ])

  AM_CONDITIONAL([HAVE_VSCRIPT],
    [test x$ax_check_vscript_flag != x])
  AM_CONDITIONAL([HAVE_VSCRIPT_COMPLEX],
    [test x$ax_check_vscript_complex_wildcards = xyes])

]) dnl AX_CHECK_VSCRIPT