Fix GDB build: ELF support check & -lzstd

GDB fails to build for me, on Ubuntu 20.04.  I get:

 ...
   CXXLD  gdb
 /usr/bin/ld: linux-tdep.o: in function `linux_corefile_thread(thread_info*, linux_corefile_thread_data*)':
 /home/pedro/gdb/binutils-gdb/src/gdb/linux-tdep.c:1831: undefined reference to `gcore_elf_build_thread_register_notes(gdbarch*, thread_info*, gdb_signal, bfd*, std::unique_ptr<char, gdb::xfree_deleter<char> >*, int*)'
 /usr/bin/ld: linux-tdep.o: in function `linux_make_corefile_notes(gdbarch*, bfd*, int*)':
 /home/pedro/gdb/binutils-gdb/src/gdb/linux-tdep.c:2117: undefined reference to `gcore_elf_make_tdesc_note(bfd*, std::unique_ptr<char, gdb::xfree_deleter<char> >*, int*)'
 collect2: error: ld returned 1 exit status
 make[2]: *** [Makefile:2149: gdb] Error 1
 make[2]: Leaving directory '/home/pedro/gdb/binutils-gdb/build/gdb'
 make[1]: *** [Makefile:11847: all-gdb] Error 2
 make[1]: Leaving directory '/home/pedro/gdb/binutils-gdb/build'
 make: *** [Makefile:1004: all] Error 2

Those undefined functions exist in gdb/gcore-elf.c, which is only
included in the build if GDB's configure thinks that the target you're
configuring for is an ELF target.  GDB's configure thinks my system
isn't ELF, which is incorrect.

For the ELF support check, gdb/config.log shows:

 configure:17387: checking for ELF support in BFD
 configure:17407: gcc -o conftest -I/home/pedro/gdb/binutils-gdb/src/gdb/../include -I../bfd -I/home/pedro/gdb/binutils-gdb/src/gdb/../bfd -g3 -O0      -L../bfd -L../libiberty  -lzstd   conftest.c -lbfd -liberty -lz  -lncursesw -lm -ldl  >&5
 /usr/bin/ld: ../bfd/libbfd.a(compress.o): in function `decompress_contents':
 /home/pedro/gdb/binutils-gdb/src/bfd/compress.c:42: undefined reference to `ZSTD_decompress'
 /usr/bin/ld: /home/pedro/gdb/binutils-gdb/src/bfd/compress.c:44: undefined reference to `ZSTD_isError'
 /usr/bin/ld: ../bfd/libbfd.a(compress.o): in function `bfd_compress_section_contents':
 /home/pedro/gdb/binutils-gdb/src/bfd/compress.c:195: undefined reference to `ZSTD_compress'
 /usr/bin/ld: /home/pedro/gdb/binutils-gdb/src/bfd/compress.c:198: undefined reference to `ZSTD_isError'
 collect2: error: ld returned 1 exit status
 configure:17407: $? = 1
 ...
 configure:17417: result: no

Note how above, in the gcc command line, "-lzstd" appears before
"-lbfd".  That explain the link failure.  It should appear after, like
-lz does.

This commit fixes it, by moving ZSTD_LIBS from LDFLAGS to LIBS, next
to -lz, in GDB_AC_CHECK_BFD, and regenerating gdb/configure.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29630
Change-Id: I1f4128dde634e8ea04c9002904f1005a8b3a6863
This commit is contained in:
Pedro Alves
2022-09-28 11:33:30 +01:00
parent e875475e19
commit 16bd13978f
2 changed files with 6 additions and 6 deletions

8
gdb/configure vendored
View File

@@ -17412,9 +17412,9 @@ WIN32LIBS="$WIN32LIBS $WIN32APILIBS"
# always want our bfd.
CFLAGS="-I${srcdir}/../include -I../bfd -I${srcdir}/../bfd $CFLAGS"
ZLIBDIR=`echo $zlibdir | sed 's,\$(top_builddir)/,,g'`
LDFLAGS="-L../bfd -L../libiberty $ZLIBDIR $ZSTD_LIBS $LDFLAGS"
LDFLAGS="-L../bfd -L../libiberty $ZLIBDIR $LDFLAGS"
intl=`echo $LIBINTL | sed 's,${top_builddir}/,,g'`
LIBS="-lbfd -liberty -lz $intl $LIBS"
LIBS="-lbfd -liberty -lz $ZSTD_LIBS $intl $LIBS"
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ELF support in BFD" >&5
$as_echo_n "checking for ELF support in BFD... " >&6; }
if ${gdb_cv_var_elf+:} false; then :
@@ -17527,9 +17527,9 @@ fi
# always want our bfd.
CFLAGS="-I${srcdir}/../include -I../bfd -I${srcdir}/../bfd $CFLAGS"
ZLIBDIR=`echo $zlibdir | sed 's,\$(top_builddir)/,,g'`
LDFLAGS="-L../bfd -L../libiberty $ZLIBDIR $ZSTD_LIBS $LDFLAGS"
LDFLAGS="-L../bfd -L../libiberty $ZLIBDIR $LDFLAGS"
intl=`echo $LIBINTL | sed 's,${top_builddir}/,,g'`
LIBS="-lbfd -liberty -lz $intl $LIBS"
LIBS="-lbfd -liberty -lz $ZSTD_LIBS $intl $LIBS"
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Mach-O support in BFD" >&5
$as_echo_n "checking for Mach-O support in BFD... " >&6; }
if ${gdb_cv_var_macho+:} false; then :