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view m4/ldd.m4 @ 17627:4d899884c95c
m4: fix gl_TIMER_TIME() detection of threads on uClibc
The timer_time.m4 gl_TIMER_TIME function determines which libraries
need to be linked to get access to the timer function, generally -lrt
for Linux systems. On platforms where threads are used, librt
typically uses thread functions from libpthread.
However, the test to determine whether the platform has thread or not
is incorrect: it assumes that if the C library is uClibc, then threads
are not available. This is actually not true: uClibc has configurable
thread support, and when thread support is available, librt calls
libpthread functions.
This is important when static linking is used, because otherwise only
-lrt is used at link time, which fails because librt calls undefined
thread functions. Both -lrt and -lpthread must be passed.
This problem is fixed by making the uClibc thread detection a bit
smarter, thanks to the usage of the __HAS_NO_THREADS__ macro defined
in <bits/uClibc_config.h>, which itself is included by <features.h>.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
| author | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
|---|---|
| date | Sat, 22 Feb 2014 00:41:38 +0100 |
| parents | 344018b6e5d7 |
| children |
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# ldd.m4 serial 1 dnl Copyright (C) 2006, 2009-2014 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. # Sets LDDPROG to a command and LDDPOSTPROC to a filter command, such that # $LDDPROG program $LDDPOSTPROC # outputs a whitespace-separated list of the dynamically linked dependencies # of the program, as library names (no full pathnames), or nothing if the # program is statically linked or if the service is not supported on the given # system. dnl From Bruno Haible. AC_DEFUN([gl_LDD], [ AC_REQUIRE([AC_CANONICAL_HOST]) AC_REQUIRE([AC_PROG_CC]) dnl Default values. LDDPROG=':' LDDPOSTPROC= dnl First try objdump, since it works when cross-compiling. AC_CHECK_TOOL([OBJDUMP], [objdump], [false]) changequote(,)dnl if test "$OBJDUMP" != "false"; then LDDPROG="$OBJDUMP -p" dnl The output of "LC_ALL=C objdump -p program" of a program or library dnl looks like this: dnl dnl libnet.so: file format elf32-i386 dnl dnl Program Header: dnl LOAD off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**12 dnl filesz 0x0001391d memsz 0x0001391d flags r-x dnl LOAD off 0x00013920 vaddr 0x00014920 paddr 0x00014920 align 2**12 dnl filesz 0x00001874 memsz 0x0001b020 flags rw- dnl DYNAMIC off 0x00015104 vaddr 0x00016104 paddr 0x00016104 align 2**2 dnl filesz 0x00000090 memsz 0x00000090 flags rw- dnl dnl Dynamic Section: dnl NEEDED libroot.so dnl SONAME libnet.so dnl SYMBOLIC 0x0 dnl INIT 0x2aec dnl FINI 0x12a2c dnl HASH 0x94 dnl STRTAB 0x1684 dnl SYMTAB 0x774 dnl STRSZ 0xbd5 dnl SYMENT 0x10 dnl PLTGOT 0x15f20 dnl PLTRELSZ 0x320 dnl PLTREL 0x11 dnl JMPREL 0x27cc dnl REL 0x225c dnl RELSZ 0x570 dnl RELENT 0x8 LDDPOSTPROC="2>/dev/null | sed -n -e 's,^ NEEDED *\\([^ ].*\\)\$,\\1,p'" else if test "$cross_compiling" = no; then dnl Not cross-compiling. Try system dependent vendor tools. case "$host_os" in aix*) LDDPROG="dump -H" dnl The output of "LC_ALL=C dump -H program" looks like this: dnl dnl program: dnl dnl ***Loader Section*** dnl Loader Header Information dnl VERSION# #SYMtableENT #RELOCent LENidSTR dnl 0x00000001 0x00000005 0x0000000d 0x0000001e dnl dnl #IMPfilID OFFidSTR LENstrTBL OFFstrTBL dnl 0x00000002 0x00000134 0x0000000d 0x00000152 dnl dnl dnl ***Import File Strings*** dnl INDEX PATH BASE MEMBER dnl 0 /usr/lib:/lib dnl 1 libc.a shr.o dnl LDDPOSTPROC="2>/dev/null | sed -e '/^[^0-9]/d' -e '/^0x/d' | sed -n -e 's,^[0-9]* *\\([^ ]*\\).*\$,\\1,p' | sed -e 's,^.*/,,'" ;; darwin*) LDDPROG="otool -L" dnl The output of "otool -L program" looks like this: dnl program: dnl /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 71.1.4) LDDPOSTPROC="2>/dev/null | sed -n -e 's,^ \\([^ ]*\\).*\$,\\1,p' | sed -e 's,^.*/,,'" ;; hpux*) LDDPROG="chatr" dnl The output of "LC_ALL=C chatr program" looks like this: dnl program: dnl shared executable dnl shared library dynamic path search: dnl SHLIB_PATH disabled second dnl embedded path disabled first Not Defined dnl shared library list: dnl dynamic /usr/lib/libc.2 dnl shared library binding: dnl deferred dnl global hash table disabled dnl plabel caching disabled dnl global hash array size:1103 dnl global hash array nbuckets:3 dnl shared vtable support disabled dnl static branch prediction disabled dnl executable from stack: D (default) dnl kernel assisted branch prediction enabled dnl lazy swap allocation disabled dnl text segment locking disabled dnl data segment locking disabled dnl third quadrant private data space disabled dnl fourth quadrant private data space disabled dnl third quadrant global data space disabled dnl data page size: D (default) dnl instruction page size: D (default) dnl nulptr references disabled dnl shared library private mapping disabled dnl shared library text merging disabled dnl dnl or like this: dnl a.out: dnl 32-bit ELF executable dnl shared library dynamic path search: dnl LD_LIBRARY_PATH enabled first dnl SHLIB_PATH enabled second dnl embedded path enabled third /usr/lib/hpux32:/opt/langtools/lib/hpux32 dnl shared library list: dnl libc.so.1 dnl shared library binding: dnl deferred dnl global hash table disabled dnl global hash table size 1103 dnl shared library mapped private disabled dnl shared library segment merging disabled dnl shared vtable support disabled dnl explicit unloading disabled dnl segments: dnl index type address flags size dnl 7 text 04000000 z---c- D (default) dnl 8 data 40000000 ---m-- D (default) dnl executable from stack: D (default) dnl kernel assisted branch prediction enabled dnl lazy swap allocation for dynamic segments disabled dnl nulptr references disabled dnl address space model: default dnl caliper dynamic instrumentation disabled dnl LDDPOSTPROC="2>/dev/null | sed -e '1,/shared library list:/d' -e '/shared library binding:/,\$d' | sed -e 's,^.*[ ]\\([^ ][^ ]*\\)\$,\\1,' | sed -e 's,^.*/,,'" ;; irix*) LDDPROG="elfdump -Dl" dnl The output of "elfdump -Dl program" looks like this: dnl dnl program: dnl dnl **** MIPS LIBLIST INFORMATION **** dnl .liblist : dnl [INDEX] Timestamp Checksum Flags Name Version dnl [1] Oct 2 05:19:12 1999 0x867bf7a8 ----- libc.so.1 sgi1.0 dnl LDDPOSTPROC="2>/dev/null | sed -n -e 's,^[[][0-9]*[]].* 0x[^ ]* [^ ][^ ]* \\([^ ][^ ]*\\).*\$,\\1,p' | sed -e 's,^.*/,,'" ;; linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu) # glibc-based systems LDDPROG="ldd" dnl The output of "ldd program" looks like this: dnl libc.so.6 => /lib/libc.so.6 (0x4002d000) dnl /lib/ld-linux.so.2 (0x40000000) LDDPOSTPROC="2>/dev/null | sed -n -e 's,^ \\([^ ][^ ]*\\).*\$,\\1,p' | sed -e 's,^.*/,,'" ;; osf*) LDDPROG="odump -Dl" dnl The output of "odump -Dl program" looks like this: dnl dnl ***LIBRARY LIST SECTION*** dnl Name Time-Stamp CheckSum Flags Version dnl program: dnl libc.so Dec 30 00:09:30 1997 0x5e955f9b 0 osf.1 dnl LDDPOSTPROC="2>/dev/null | sed -n -e 's,^ \\([^ ][^ ]*\\).*,\\1,p' | sed -e '/^Name\$/d' | sed -e 's,^.*/,,'" ;; solaris*) LDDPROG="ldd" dnl The output of "ldd program" looks like this: dnl libc.so.1 => /usr/lib/libc.so.1 dnl libdl.so.1 => /usr/lib/libdl.so.1 dnl /usr/platform/SUNW,Ultra-5_10/lib/libc_psr.so.1 dnl The first sed collects the indented lines. dnl The second sed extracts the left-hand part. dnl The third sed removes directory specifications. LDDPOSTPROC="2>/dev/null | sed -n -e 's,^ \\([^ ].*\\)\$,\\1,p' | sed -e 's, =>.*\$,,' | sed -e 's,^.*/,,'" ;; esac fi fi dnl Avoid locale dependencies. if test "$LDDPROG" != ":"; then LDDPROG="LC_ALL=C $LDDPROG" fi changequote([,])dnl AC_SUBST([LDDPROG]) AC_SUBST([LDDPOSTPROC]) ])