[1/2] toolchain: generate a gdbinit file

This commit slightly improves the external toolchain backend, and the
gdb build logic to create a file named
$(STAGING_DIR)/usr/share/buildroot/gdbinit which can be used as a
gdbinit file using gdb -x option. This allows gdb to automatically use
the proper sysroot to find libraries.

The initial insight for this patch comes from the report of Oded
Hanson <OHanson@xsightsys.com>, who found an issue with the Eclipse
Buildroot plugin, which was setting a solib-path in gdb, but not a
sysroot. Setting a solib-path was enough to find shared libraries, but
not the dynamic linker. And since Eclipse doesn't allow to set the
sysroot in any other way that giving a gdbinit file, it makes sense to
have Buildroot generate a gdbinit file (which was be used in other
situations than Eclipse).

To achieve this, this commit introduces a gen_gdbinit_file helper in
toolchain/helpers.mk, and uses it for the internal toolchain and
external toolchain backends.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 package/gdb/gdb.mk                                 | 2 ++
 toolchain/helpers.mk                               | 7 +++++++
 toolchain/toolchain-external/toolchain-external.mk | 7 +++++++
 3 files changed, 16 insertions(+)

Hi Thomas,

On Tue, Mar 04, 2014 at 10:41:24PM +0100, Thomas Petazzoni wrote:
> This commit slightly improves the external toolchain backend, and the
> gdb build logic to create a file named
> $(STAGING_DIR)/usr/share/buildroot/gdbinit which can be used as a
> gdbinit file using gdb -x option. This allows gdb to automatically use
> the proper sysroot to find libraries.
> 
> The initial insight for this patch comes from the report of Oded
> Hanson <OHanson@xsightsys.com>, who found an issue with the Eclipse
> Buildroot plugin, which was setting a solib-path in gdb, but not a
> sysroot. Setting a solib-path was enough to find shared libraries, but
> not the dynamic linker. And since Eclipse doesn't allow to set the
> sysroot in any other way that giving a gdbinit file, it makes sense to

s/that/than/

baurch

> have Buildroot generate a gdbinit file (which was be used in other
> situations than Eclipse).
> 
> To achieve this, this commit introduces a gen_gdbinit_file helper in
> toolchain/helpers.mk, and uses it for the internal toolchain and
> external toolchain backends.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>  package/gdb/gdb.mk                                 | 2 ++
>  toolchain/helpers.mk                               | 7 +++++++
>  toolchain/toolchain-external/toolchain-external.mk | 7 +++++++
>  3 files changed, 16 insertions(+)
> 
> diff --git a/package/gdb/gdb.mk b/package/gdb/gdb.mk
> index 69fb3ba..678c17c 100644
> --- a/package/gdb/gdb.mk
> +++ b/package/gdb/gdb.mk
> @@ -126,5 +126,7 @@ endef
>  
>  HOST_GDB_POST_INSTALL_HOOKS += HOST_GDB_ADD_SYMLINK
>  
> +HOST_GDB_POST_INSTALL_HOOKS += gen_gdbinit_file
> +
>  $(eval $(autotools-package))
>  $(eval $(host-autotools-package))
> diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk
> index 64d5095..668a737 100644
> --- a/toolchain/helpers.mk
> +++ b/toolchain/helpers.mk
> @@ -356,3 +356,10 @@ check_unusable_toolchain = \
>  		echo "such as Buildroot." ; \
>  		exit 1 ; \
>  	fi
> +
> +#
> +# Generate gdbinit file for use with Buildroot
> +#
> +gen_gdbinit_file = \
> +	mkdir -p $(STAGING_DIR)/usr/share/buildroot/ ; \
> +	echo "set sysroot $(STAGING_DIR)" > $(STAGING_DIR)/usr/share/buildroot/gdbinit
> diff --git a/toolchain/toolchain-external/toolchain-external.mk b/toolchain/toolchain-external/toolchain-external.mk
> index 378e7b2..b45504b 100644
> --- a/toolchain/toolchain-external/toolchain-external.mk
> +++ b/toolchain/toolchain-external/toolchain-external.mk
> @@ -617,6 +617,12 @@ define TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER
>  		-o $(HOST_DIR)/usr/bin/ext-toolchain-wrapper
>  endef
>  
> +define TOOLCHAIN_EXTERNAL_INSTALL_GDBINIT
> +	if test -f $(TARGET_CROSS)gdb ; then \
> +		$(call gen_gdbinit_file) ; \
> +	fi
> +endef
> +
>  # Even though we're installing things in both the staging, the host
>  # and the target directory, we do everything within the
>  # install-staging step, arbitrarily.
> @@ -625,6 +631,7 @@ define TOOLCHAIN_EXTERNAL_INSTALL_STAGING_CMDS
>  	$(TOOLCHAIN_EXTERNAL_INSTALL_BFIN_FDPIC)
>  	$(TOOLCHAIN_EXTERNAL_INSTALL_BFIN_FLAT)
>  	$(TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER)
> +	$(TOOLCHAIN_EXTERNAL_INSTALL_GDBINIT)
>  endef
>  
>  $(eval $(generic-package))
> -- 
> 1.8.3.2