diff options
| -rw-r--r-- | CMakeLists.txt | 5 | ||||
| -rw-r--r-- | configure.ac | 143 | ||||
| -rw-r--r-- | src/liblzma/common/common.h | 12 |
3 files changed, 111 insertions, 49 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index 143a2cbf..5adc3c0a 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -477,7 +477,10 @@ elseif(BUILD_SHARED_LIBS AND CMAKE_SYSTEM_NAME STREQUAL "Linux") # because it would put symbol versions into the static library which # can cause problems. It's clearer if all symver related things are # omitted when not building a shared library. - target_compile_definitions(liblzma PRIVATE HAVE_SYMBOL_VERSIONS_LINUX) + # + # NOTE: Set it explicitly to 1 to make it clear that versioning is + # done unconditionally in the C files. + target_compile_definitions(liblzma PRIVATE HAVE_SYMBOL_VERSIONS_LINUX=1) target_link_options(liblzma PRIVATE "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/src/liblzma/liblzma_linux.map" ) diff --git a/configure.ac b/configure.ac index 60a63825..30ed89a6 100644 --- a/configure.ac +++ b/configure.ac @@ -520,54 +520,6 @@ AC_ARG_ENABLE([doc], [AS_HELP_STRING([--disable-doc], AM_CONDITIONAL([COND_DOC], [test x$enable_doc != xno]) -##################### -# Symbol versioning # -##################### - -AC_MSG_CHECKING([if library symbol versioning should be used]) -AC_ARG_ENABLE([symbol-versions], [AS_HELP_STRING([--enable-symbol-versions], - [Use symbol versioning for liblzma. Enabled by default on - GNU/Linux, other GNU-based systems, and FreeBSD.])], - [], [enable_symbol_versions=auto]) -if test "x$enable_symbol_versions" = xauto; then - case $host_os in - # NOTE: Even if one omits -gnu on GNU/Linux (e.g. - # i486-slackware-linux), configure will (via config.sub) - # append -gnu (e.g. i486-slackware-linux-gnu), and this - # test will work correctly. - gnu* | *-gnu* | freebsd*) - enable_symbol_versions=yes - ;; - *) - enable_symbol_versions=no - ;; - esac -fi -AC_MSG_RESULT([$enable_symbol_versions]) - -# There are two variants for symbol versioning. -# See src/liblzma/validate_map.sh for details. -if test "x$enable_symbol_versions" = xyes; then - case $host_os in - linux*) - enable_symbol_versions=linux - AC_DEFINE([HAVE_SYMBOL_VERSIONS_LINUX], [1], - [Define to 1 to if GNU/Linux-specific details - are wanted for symbol versioning. This must - be used together with liblzma_linux.map.]) - ;; - *) - enable_symbol_versions=generic - ;; - esac -fi - -AM_CONDITIONAL([COND_SYMVERS_LINUX], - [test "x$enable_symbol_versions" = xlinux]) -AM_CONDITIONAL([COND_SYMVERS_GENERIC], - [test "x$enable_symbol_versions" = xgeneric]) - - ############## # Sandboxing # ############## @@ -715,6 +667,101 @@ LT_LANG([Windows Resource]) # libs as shared. AM_CONDITIONAL([COND_SHARED], [test "x$enable_shared" != xno]) +##################### +# Symbol versioning # +##################### + +# NOTE: This checks if we are building shared or static library +# and if --with-pic or --without-pic was used. Thus this check +# must be after Libtool initialization. +AC_MSG_CHECKING([if library symbol versioning should be used]) +AC_ARG_ENABLE([symbol-versions], [AS_HELP_STRING([--enable-symbol-versions], + [Use symbol versioning for liblzma. Enabled by default on + GNU/Linux, other GNU-based systems, and FreeBSD.])], + [], [enable_symbol_versions=auto]) +if test "x$enable_symbol_versions" = xauto; then + case $host_os in + # NOTE: Even if one omits -gnu on GNU/Linux (e.g. + # i486-slackware-linux), configure will (via config.sub) + # append -gnu (e.g. i486-slackware-linux-gnu), and this + # test will work correctly. + gnu* | *-gnu* | freebsd*) + enable_symbol_versions=yes + ;; + *) + enable_symbol_versions=no + ;; + esac +fi + +# There are two variants for symbol versioning. +# See src/liblzma/validate_map.sh for details. +# +# On GNU/Linux, extra symbols are added in the C code. These extra symbols +# must not be put into a static library as they can cause problems (and +# even if they didn't cause problems, they would be useless). On other +# systems symbol versioning may be used too but there is no problem as only +# a linker script is specified in src/liblzma/Makefile.am and that isn't +# used when creating a static library. +# +# Libtool always uses -DPIC when building shared libraries by default and +# doesn't use it for static libs by default. This can be overriden with +# --with-pic and --without-pic though. As long as neither --with-pic nor +# --without-pic is used then we can use #ifdef PIC to detect if the file is +# being built for a shared library. +if test "x$enable_symbol_versions" = xno ; then + enable_symbol_versions=no + AC_MSG_RESULT([no]) +elif test "x$enable_shared" = xno ; then + enable_symbol_versions=no + AC_MSG_RESULT([no (not building a shared library)]) +else + case $host_os in + linux*) + case "$pic_mode-$enable_static" in + default-*) + # Use symvers if PIC is defined. + have_symbol_versions_linux=2 + ;; + *-no) + # Not building static library. + # Use symvers unconditionally. + have_symbol_versions_linux=1 + ;; + *) + AC_MSG_RESULT([]) + AC_MSG_ERROR([ + On GNU/Linux, building both shared and static library at the same time + is not supported if --with-pic or --without-pic is used. + Use either --disable-shared or --disable-static to build one type + of library at a time. If both types are needed, build one at a time, + possibly picking only src/liblzma/.libs/liblzma.a from the static build.]) + ;; + esac + enable_symbol_versions=linux + AC_DEFINE_UNQUOTED([HAVE_SYMBOL_VERSIONS_LINUX], + [$have_symbol_versions_linux], + [Define to 1 to if GNU/Linux-specific details + are unconditionally wanted for symbol + versioning. Define to 2 to if these are wanted + only if also PIC is defined (allows building + both shared and static liblzma at the same + time with Libtool if neither --with-pic nor + --without-pic is used). This define must be + used together with liblzma_linux.map.]) + ;; + *) + enable_symbol_versions=generic + ;; + esac + AC_MSG_RESULT([yes ($enable_symbol_versions)]) +fi + +AM_CONDITIONAL([COND_SYMVERS_LINUX], + [test "x$enable_symbol_versions" = xlinux]) +AM_CONDITIONAL([COND_SYMVERS_GENERIC], + [test "x$enable_symbol_versions" = xgeneric]) + ############################################################################### # Checks for libraries. diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h index 1ca536be..b3a624c6 100644 --- a/src/liblzma/common/common.h +++ b/src/liblzma/common/common.h @@ -34,6 +34,18 @@ #include "lzma.h" +// The extra symbol versioning in the C files may only be used when +// building a shared library. If HAVE_SYMBOL_VERSIONS_LINUX is defined +// to 2 then symbol versioning is done only if also PIC is defined. +// By default Libtool defines PIC when building a shared library and +// doesn't define it when building a static library but it can be +// overriden with --with-pic and --without-pic. configure let's rely +// on PIC if neither --with-pic or --without-pic was used. +#if defined(HAVE_SYMBOL_VERSIONS_LINUX) \ + && (HAVE_SYMBOL_VERSIONS_LINUX == 2 && !defined(PIC)) +# undef HAVE_SYMBOL_VERSIONS_LINUX +#endif + #ifdef HAVE_SYMBOL_VERSIONS_LINUX // To keep link-time optimization (LTO, -flto) working with GCC, // the __symver__ attribute must be used instead of __asm__(".symver ..."). |