Bug 8786 - gdb fails to build with xz and expat support at the same
Summary: gdb fails to build with xz and expat support at the same
Status: RESOLVED FIXED
Alias: None
Product: buildroot
Classification: Unclassified
Component: Other (show other bugs)
Version: unspecified
Hardware: All Linux
: P5 normal
Target Milestone: ---
Assignee: unassigned
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2016-03-10 14:56 UTC by Vicente Olivert Riera
Modified: 2016-04-19 21:28 UTC (History)
1 user (show)

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Description Vicente Olivert Riera 2016-03-10 14:56:47 UTC 
For some reason gdb fails to build with xz and expat support at the same
time when using an external toolchain.

This is how the problem is shown:

checking for liblzma... no
configure: error: missing liblzma for --with-lzma

Try this defconfig if you want to reproduce the problem:

BR2_x86_64=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_PACKAGE_XZ=y
BR2_PACKAGE_GDB=y
BR2_PACKAGE_GDB_DEBUGGER=y
BR2_PACKAGE_EXPAT=y

Using the above defconfig, the error in the gdb/config.log will look
like this:

configure:13241: checking whether to use lzma
configure:13243: result: yes
configure:13657: checking for liblzma
configure:13678: /br/output/host/usr/bin/i686-pc-linux-gnu-gcc -o
conftest -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64  -Os
-I/br/output/host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/include
-static-libstdc++ -static-libgcc  conftest.c -ldl -ldl -lncurses -lm
-ldl    /usr/lib/liblzma.so >&5
/lib64/liblzma.so.5: undefined reference to `clock_gettime@GLIBC_2.17'
collect2: error: ld returned 1 exit status

You can also use this defconfig to reproduce the problem for MIPS:

BR2_mips=y
BR2_mips_32r2=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_PACKAGE_XZ=y
BR2_PACKAGE_GDB=y
BR2_PACKAGE_GDB_DEBUGGER=y
BR2_PACKAGE_EXPAT=y

In that case the error will look like this:

configure:13241: checking whether to use lzma
configure:13243: result: yes
configure:13657: checking for liblzma
configure:13678: /br/output/host/usr/bin/mips-linux-gnu-gcc -o conftest
-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os
 -I/br/output/host/usr/mips-buildroot-linux-gnu/sysroot/usr/include
-static-libstdc++ -static-libgcc  conftest.c -ldl -ldl -lncurses -lm
-ldl    /usr/lib/liblzma.so >&5
/br/output/host/opt/ext-toolchain/bin/../lib/gcc/mips-linux-gnu/5.2.0/../../../../mips-linux-gnu/bin/ld:
skipping incompatible /lib64/liblzma.so.5 when searching for
/lib64/liblzma.so.5
/br/output/host/opt/ext-toolchain/bin/../lib/gcc/mips-linux-gnu/5.2.0/../../../../mips-linux-gnu/bin/ld:
cannot find /lib64/liblzma.so.5
collect2: error: ld returned 1 exit status

You can also use this defconfig to reproduce the problem for ARM:

BR2_arm=y
BR2_cortex_a7=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_PACKAGE_XZ=y
BR2_PACKAGE_GDB=y
BR2_PACKAGE_GDB_DEBUGGER=y
BR2_PACKAGE_EXPAT=y

In that case the error will look like this:

configure:13241: checking whether to use lzma
configure:13243: result: yes
configure:13657: checking for liblzma
configure:13678: /br/output/host/usr/bin/arm-linux-gnueabihf-gcc -o
conftest -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64  -Os
-I/br/output/host/usr/arm-buildroot-linux-gnueabihf/sysroot/usr/include
-static-libstdc++ -static-libgcc  conftest.c -ldl -ldl -lncurses -lm
-ldl    /usr/lib/liblzma.so >&5
/lib64/liblzma.so.5: file not recognized: File format not recognized
collect2: error: ld returned 1 exit status
Comment 1 Thomas Petazzoni 2016-03-10 16:44:57 UTC 
The problem seems related to the fact that you have lzma installed on your build machine, including the development files.

I've tested your last defconfig (on ARM), and I'm not able to reproduce, either with lzma development files installed or not installed.

The failure:

/lib64/liblzma.so.5: undefined reference to `clock_gettime@GLIBC_2.17'

is related to the fact that it finds your host lzma, tries to link with it, but fails because it lacks -lrt.

Can you try --with-lzma-prefix=$(HOST_DIR)/usr in GDB_CONF_OPTS ?
Comment 2 Vicente Olivert Riera 2016-03-10 17:23:36 UTC 
That fixes the problem. I've sent a patch:

http://patchwork.ozlabs.org/patch/595861/
Comment 3 Thomas Petazzoni 2016-04-19 21:28:10 UTC 
Fixed in e6a29a4f3c48b13fde2214365067e34fbb92cfd6.