Build fail in installing native gdb: libexpat.so not recognized

[ryanmwe]

crosstool-NG version: 1.26.0.40_6cf65db
Host OS: Arch Linux x86_64 6.7.0-arch3-1
Config and Build Log:
logs.tar.gz

[ALL ] /usr/lib/libexpat.so: file not recognized: file format not recognized
[ERROR] collect2: error: ld returned 1 exit status
[ERROR] make[3]: *** [Makefile:2177: gdb] Error 1
[ALL ] make[3]: Leaving directory '/home/cosca/crosstool-ng/.build/arm-cortex_a8-linux-gnueabihf/build/build-gdb-native/gdb'
[ERROR] make[2]: *** [Makefile:11319: all-gdb] Error 2
[ALL ] make[2]: Leaving directory '/home/cosca/crosstool-ng/.build/arm-cortex_a8-linux-gnueabihf/build/build-gdb-native'
[ERROR] make[1]: *** [Makefile:1021: all] Error 2
[ALL ] make[1]: Leaving directory '/home/cosca/crosstool-ng/.build/arm-cortex_a8-linux-gnueabihf/build/build-gdb-native'
[ERROR]
[ERROR] >>
[ERROR] >> Build failed in step 'Installing native gdb'
[ERROR] >> called in step '(top-level)'
[ERROR] >>
[ERROR] >> Error happened in: CT_DoExecLog[scripts/functions@377]
[ERROR] >> called from: do_gdb_backend[scripts/build/debug/300-gdb.sh@361]
[ERROR] >> called from: do_debug_gdb_build[scripts/build/debug/300-gdb.sh@182]
[ERROR] >> called from: do_debug[scripts/build/debug.sh@35]
[ERROR] >> called from: main[scripts/crosstool-NG.sh@708]
[ERROR] >>
[ERROR] >> For more info on this error, look at the file: 'build.log'
[ERROR] >> There is a list of known issues, some with workarounds, in:
[ERROR] >> https://crosstool-ng.github.io/docs/known-issues/
[ERROR] >>
[ERROR] >> If you feel this is a bug in crosstool-NG, report it at:
[ERROR] >> https://github.com/crosstool-ng/crosstool-ng/issues/
[ERROR] >>
[ERROR] >> Make sure your report includes all the information pertinent to this issue.
[ERROR] >> Read the bug reporting guidelines here:
[ERROR] >> http://crosstool-ng.github.io/support/
[ERROR]
[ERROR] (elapsed: 14:31.04)

[QBos07]

The build libexpat was schosen instead of the target one.
Can we get /home/cosca/crosstool-ng/.build/arm-cortex_a8-linux-gnueabihf/build/build-gdb-native/gdb/config.log for further analysis?

[ryanmwe]

config.log

[QBos07]

Seems like configure picked up expat correctly. Message ID: ***@***.***>

[cpackham]

I tried building your config in a debain based container and it built fine. I switched to an arch based one and hit the error. I think part of the problem is that debian ends up installing libexpat under /usr/lib/x86_64-linux-gnu/libexpat.so while arch has it in /usr/lib/libexpat.so. The latter being a fairly default place configure tends to find stuff.

[cpackham]

Looks like this code attempts to handle this but obviously that's not working anymore.

[ryanmwe]

Thanks. Ive had the same result using ubuntu, seems to work there. I'll play around that section a little to see if I can make something work on my arch computer.

[RafalBanaszak]

Hi @ryanmwe ,
I had same issue and solved it using this patch:

diff --git a/scripts/build/debug/300-gdb.sh b/scripts/build/debug/300-gdb.sh
index 73c56c9e..65bc427b 100644
--- a/scripts/build/debug/300-gdb.sh
+++ b/scripts/build/debug/300-gdb.sh
@@ -66,8 +66,8 @@ do_debug_gdb_build()
         # version of expat and will attempt to link that, despite the -static flag.
         # The link will fail, and configure will abort with "expat missing or unusable"
         # message.
-        extra_config+=("--with-expat")
-        extra_config+=("--without-libexpat-prefix")
+        cross_extra_config+=("--with-expat")
+        #cross_extra_config+=("--without-libexpat-prefix")
 
         # ct-ng always builds ncurses in cross mode as a static library.
         # Starting from the patchset 20200718 ncurses defines a special macro
@@ -184,7 +184,8 @@ do_debug_gdb_build()
         # The link will fail, and configure will abort with "expat missing or unusable"
         # message.
         native_extra_config+=("--with-expat")
-        native_extra_config+=("--without-libexpat-prefix")
+        native_extra_config+=("--with-libexpat-type=static")
+        native_extra_config+=("--with-libexpat-prefix=${CT_SYSROOT_DIR}/usr")
 
         do_gdb_backend \
             buildtype=native \

I have found following issues:

1. extra_config isn't used in the script. The script uses cross_extra_config and native_extra_config.
2. <cross>_extra_config+=("--without-libexpat-prefix") doesn't make much sense. Expat on arch is in /usr/lib and the configure script doesn't need any extra options to link it to the cross GDB (cross means executed on your host machine to remotely debug a target). The comment above <cross>_extra_config is copied from native_extra_config and very misleading.
3. The native GDB (executed on the target to debug target programs) requires to explicitly pass a path to the sysroot. native_extra_config+=("--without-libexpat-prefix") didn't change this behavior and a cross compiler still takes libexpat from /usr/lib. native_extra_config+=("--with-libexpat-prefix=${CT_SYSROOT_DIR}/usr") solved the problem.

I noticed the results of the scripts are cached somehow and applying patch isn't enough. I had cleaned the repo (git clean -xfd), applied the patch and then built the crosstool-ng from scratch (./bootstrap, ./configure... and so on). Most probably it's an overkill but works for me.

[ryanmwe]

This patch worked for me, I also built crosstool-ng from scratch