[Buildroot] [PATCH 2/3] toolchain/toolchain-external: fixup gdb pretty-printer loader for libstdcxx

[Thomas De Schampheleire]

El mar, 8 jun 2021 a las 15:06, Thomas De Schampheleire
(<patrickdepinguin at gmail.com>) escribió:
>
> From: Thomas De Schampheleire <thomas.de_schampheleire at nokia.com>
>
> gcc installs a libstdcxx-...so-gdb.py file that gdb will load automatically
> when it loads libstdcxx.so, via the mechanism described at [1].
>
> However, the auto-load file installed by gcc contains hardcoded paths
> referring to the location where the (external) toolchain was built, which
> are normally not available.
>
> Fix up the paths in the load file so that the pretty printers can be loaded
> automatically.
>
> Note that gdb will only auto-load the file if its location is marked as
> 'safe'. A subsequent commit will take care of that.
>
> [1] https://sourceware.org/gdb/onlinedocs/gdb/objfile_002dgdbdotext-file.html
>
> Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire at nokia.com>
> ---
>  .../pkg-toolchain-external.mk                 | 21 +++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/toolchain/toolchain-external/pkg-toolchain-external.mk b/toolchain/toolchain-external/pkg-toolchain-external.mk
> index 6d91cb5d1e..1b519d1832 100644
> --- a/toolchain/toolchain-external/pkg-toolchain-external.mk
> +++ b/toolchain/toolchain-external/pkg-toolchain-external.mk
> @@ -485,6 +485,26 @@ define TOOLCHAIN_EXTERNAL_INSTALL_GDBINIT
>         fi
>  endef
>
> +# GCC installs a libstdcxx-...so-gdb.py file that gdb will load automatically,
> +# but it contains hardcoded paths referring to the location where the (external)
> +# toolchain was built. Fix up these paths so that the pretty printers can be
> +# loaded automatically.
> +# By default, the pretty printers are installed in
> +# $(datadir)/gcc-$(gcc_version)/python but this could have been overwritten with
> +# the gcc configure option: --with-python-dir. We thus have to search the
> +# correct path first.
> +define TOOLCHAIN_EXTERNAL_FIXUP_PRETTY_PRINTER_LOADER
> +       loadfile=$$(find $(STAGING_DIR) -name 'libstdc++.so*-gdb.py' 2>/dev/null); \
> +       pythondir=$$(find $(TOOLCHAIN_EXTERNAL_DOWNLOAD_INSTALL_DIR) -path '*/libstdcxx/__init__.py' 2>/dev/null | xargs dirname | xargs dirname); \
> +       if [ -n "$$loadfile" ] && [ -n "$$pythondir" ]; then \
> +               echo "Fixing up hardcoded paths in GDB pretty-printer auto-load file for libstdcxx: $$loadfile"; \
> +               sed -ri \
> +                       -e 's%^libdir\s*=.*%libdir = "$(STAGING_DIR)/lib"%' \
> +                       -e "s%^pythondir\s*=.*%pythondir = '$$pythondir'%" \
> +                       $$loadfile; \

In one build I'm seeing a problem with this sed command, so I will
need to double check it.
I will get back to this...