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authorYang Tse <yangsita@gmail.com>2009-10-28 19:45:26 +0000
committerYang Tse <yangsita@gmail.com>2009-10-28 19:45:26 +0000
commit0d9f14f5c17e4a3888dedbc8d568a55979fc05f0 (patch)
tree876a88fbc370edca79dbd0a0ea3eef31a550a6ad /ares/m4
parent9fced16efb544dc37fe54b8ed94622ed22dd55be (diff)
Initial step towards the ability to reduce c-ares exported symbols
based on the 'visibility' attribute for GNUC and __global for Sun compilers, taking also in account __declspec function decoration for Win32 and Symbian DLL's. Introducing configure options --enable-hidden-symbols and --disable-hidden-symbols following libcurl's naming.
Diffstat (limited to 'ares/m4')
-rw-r--r--ares/m4/cares-compilers.m496
-rw-r--r--ares/m4/cares-confopts.m463
2 files changed, 157 insertions, 2 deletions
diff --git a/ares/m4/cares-compilers.m4 b/ares/m4/cares-compilers.m4
index e4fd1ec63..77e4651a7 100644
--- a/ares/m4/cares-compilers.m4
+++ b/ares/m4/cares-compilers.m4
@@ -16,7 +16,7 @@
#***************************************************************************
# File version for 'aclocal' use. Keep it a single number.
-# serial 56
+# serial 59
dnl CARES_CHECK_COMPILER
@@ -1249,6 +1249,100 @@ AC_DEFUN([CARES_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE], [
])
+dnl CARES_CHECK_COMPILER_HIDDEN_SYMBOLS
+dnl -------------------------------------------------
+dnl Verify if compiler supports hiding library internal symbols, setting
+dnl shell variable hidden_symbols_supported value as appropriate, as well
+dnl as variable hidden_symbols_CFLAGS when supported.
+
+AC_DEFUN([CARES_CHECK_COMPILER_HIDDEN_SYMBOLS], [
+ AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+ AC_BEFORE([$0],[CARES_CONFIGURE_HIDDEN_SYMBOLS])dnl
+ AC_MSG_CHECKING([if compiler supports hiding library internal symbols])
+ hidden_symbols_supported="no"
+ hidden_symbols_CFLAGS=""
+ tmp_CFLAGS=""
+ tmp_extern=""
+ case "$compiler_id" in
+ GNU_C)
+ dnl Only gcc 3.4 or later
+ if test "$compiler_num" -ge "304"; then
+ if $CC --help --verbose 2>&1 | grep fvisibility= > /dev/null ; then
+ tmp_extern="__attribute__ ((visibility (\"default\")))"
+ tmp_CFLAGS="-fvisibility=hidden"
+ hidden_symbols_supported="yes"
+ echo " " >&6
+ echo "debug: should work with this compiler and version" >&6
+ echo " " >&6
+ fi
+ fi
+ ;;
+ INTEL_UNIX_C)
+ dnl Only icc 9.0 or later
+ if test "$compiler_num" -ge "900"; then
+ if $CC --help --verbose 2>&1 | grep fvisibility= > /dev/null ; then
+ tmp_extern="__attribute__ ((visibility (\"default\")))"
+ tmp_CFLAGS="-fvisibility=hidden"
+ hidden_symbols_supported="yes"
+ echo " " >&6
+ echo "debug: should work with this compiler and version" >&6
+ echo " " >&6
+ fi
+ fi
+ ;;
+ SUNPRO_C)
+ if $CC 2>&1 | grep flags >/dev/null && $CC -flags | grep xldscope= >/dev/null ; then
+ tmp_extern="__global"
+ tmp_CFLAGS="-xldscope=hidden"
+ hidden_symbols_supported="yes"
+ echo " " >&6
+ echo "debug: should work with this compiler and version" >&6
+ echo " " >&6
+ fi
+ ;;
+ esac
+ if test "$hidden_symbols_supported" = "yes"; then
+ tmp_save_CFLAGS="$CFLAGS"
+ CFLAGS="$tmp_save_CFLAGS $tmp_CFLAGS"
+ squeeze CFLAGS
+ AC_COMPILE_IFELSE([
+ AC_LANG_PROGRAM([[
+ $tmp_extern char *dummy(char *buff);
+ char *dummy(char *buff)
+ {
+ if(buff)
+ return ++buff;
+ else
+ return buff;
+ }
+ ]],[[
+ char b[16];
+ char *r = dummy(&b);
+ if(r)
+ return (int)*r;
+ ]])
+ ],[
+ hidden_symbols_supported="yes"
+ ],[
+ hidden_symbols_supported="no"
+ sed 's/^/cc-src: /' conftest.$ac_ext >&6
+ sed 's/^/cc-err: /' conftest.err >&6
+ ])
+ CFLAGS="$tmp_save_CFLAGS"
+ fi
+ if test "$hidden_symbols_supported" = "yes"; then
+ AC_MSG_RESULT([yes])
+ AC_DEFINE_UNQUOTED(CARES_HIDDEN_SYMBOLS, 1,
+ [Define to 1 to enable hiding of library internal symbols.])
+ AC_DEFINE_UNQUOTED(CARES_EXTERN_SYMBOL, $tmp_extern,
+ [Definition to make a library symbol externally visible.])
+ hidden_symbols_CFLAGS="$tmp_CFLAGS"
+ else
+ AC_MSG_RESULT([no])
+ fi
+])
+
+
dnl CARES_CHECK_COMPILER_STRUCT_MEMBER_SIZE
dnl -------------------------------------------------
dnl Verifies if the compiler is capable of handling the
diff --git a/ares/m4/cares-confopts.m4 b/ares/m4/cares-confopts.m4
index cc03a09d6..5af3232ad 100644
--- a/ares/m4/cares-confopts.m4
+++ b/ares/m4/cares-confopts.m4
@@ -16,7 +16,7 @@
#***************************************************************************
# File version for 'aclocal' use. Keep it a single number.
-# serial 5
+# serial 6
dnl CARES_CHECK_OPTION_CURLDEBUG
@@ -92,6 +92,46 @@ AC_HELP_STRING([--disable-debug],[Disable debug build options]),
])
+dnl CARES_CHECK_OPTION_HIDDEN_SYMBOLS
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-hidden-symbols or --disable-hidden-symbols,
+dnl setting shell variable want_hidden_symbols value.
+
+AC_DEFUN([CARES_CHECK_OPTION_HIDDEN_SYMBOLS], [
+ AC_BEFORE([$0],[CARES_CHECK_COMPILER_HIDDEN_SYMBOLS])dnl
+ AC_MSG_CHECKING([whether to enable hiding symbols])
+ OPT_HIDDEN_SYMBOLS="default"
+ AC_ARG_ENABLE(hidden-symbols,
+AC_HELP_STRING([--enable-hidden-symbols],[Enable hiding of library internal symbols])
+AC_HELP_STRING([--disable-hidden-symbols],[Disable hiding of library internal symbols]),
+ OPT_HIDDEN_SYMBOLS=$enableval)
+ case "$OPT_HIDDEN_SYMBOLS" in
+ no)
+ dnl --disable-hidden-symbols option used.
+ dnl This is an indication to not attempt hiding of library internal
+ dnl symbols. Default symbol visibility will be used, which normally
+ dnl exposes all library internal symbols.
+ want_hidden_symbols="no"
+ AC_MSG_RESULT([no])
+ ;;
+ default)
+ dnl configure's hidden-symbols option not specified.
+ dnl Handle this as if --enable-hidden-symbols option was given.
+ want_hidden_symbols="yes"
+ AC_MSG_RESULT([not specified (assuming yes)])
+ ;;
+ *)
+ dnl --enable-hidden-symbols option used.
+ dnl This is an indication to attempt hiding of library internal
+ dnl symbols. This is only supported on some compilers/linkers.
+ want_hidden_symbols="yes"
+ AC_MSG_RESULT([yes])
+ ;;
+ esac
+])
+
+
dnl CARES_CHECK_OPTION_NONBLOCKING
dnl -------------------------------------------------
dnl Verify if configure has been invoked with option
@@ -252,3 +292,24 @@ AC_DEFUN([CARES_CHECK_NONBLOCKING_SOCKET], [
fi
])
+
+dnl CARES_CONFIGURE_HIDDEN_SYMBOLS
+dnl -------------------------------------------------
+dnl Depending on --enable-hidden-symbols or --disable-hidden-symbols
+dnl configure option, and compiler capability to actually honor such
+dnl option, compiler flags will be modified as appropriate.
+dnl This macro should not be used until all compilation tests have
+dnl been done to prevent interferences on other tests.
+
+AC_DEFUN([CARES_CONFIGURE_HIDDEN_SYMBOLS], [
+ AC_MSG_CHECKING([whether to actually hide library internal symbols])
+ if test "$want_hidden_symbols" = "yes" &&
+ test "$hidden_symbols_supported" = "yes"; then
+ tmp_save_CFLAGS="$CFLAGS"
+ CFLAGS="$tmp_save_CFLAGS $hidden_symbols_CFLAGS"
+ AC_MSG_RESULT([yes])
+ else
+ AC_MSG_RESULT([no])
+ fi
+])
+