Toolchain Overlay File

Introduction

The Overlay is a tar file that includes modified versions of processor configuration dependent files that are required by various toolchain tools, such as binutils, gcc, and gdb. The overlay described here has a specific layout and is intended for toolchain generators, such as buildroot or crosstool-NG.

Creating the overlay

The overlay file shipped by Tensilica uses a flat directory structure, which is not suitable for buildroot or crosstool-NG at the moment. It is part of the generated processor package, and can be found in the XtDevTools directory:

XtDevTools/install/build/$VERSION/$XTENSA_CORE/src/xtensa-config-overlay.tar.gz

The following script converts the directory structure of that file by creating a new overlay file, called xtensa-overlay.tgz, and extracting the necessary files from the Tensilica overlay. Simply provide the path and name of the overlay provided by Tensilica when running the script:

./script xtensa-config-overlay.tar.gz

This will create the file xtensa-overlay.tgz required by buildroot or crosstool-NG. For more information how to configure those generators, please see Buildroot or crosstool-NG.

(Note that there is also a similar file under .../$XTENSA_CORE/xtensa-elf/src/linux/misc/linux-overlay.tar.gz. This file has a different layout structure and doesn't work with the script below)

Conversion Script

#!/bin/sh
TMPDIR=`mktemp -d`
tar xzf $1 -C $TMPDIR
mkdir -p $TMPDIR/overlay/binutils/bfd $TMPDIR/overlay/binutils/ld \
         $TMPDIR/overlay/binutils/include $TMPDIR/overlay/gcc/include \
         $TMPDIR/overlay/gdb/bfd $TMPDIR/overlay/gdb/gdb/regformats \
         $TMPDIR/overlay/gdb/gdb/gdbserver $TMPDIR/overlay/gdb/include
mv $TMPDIR/binutils/xtensa-config.h $TMPDIR/overlay/binutils/include
mv $TMPDIR/binutils/xtensa-modules.c $TMPDIR/overlay/binutils/bfd
mv $TMPDIR/gcc/xtensa-config.h $TMPDIR/overlay/gcc/include
mv $TMPDIR/gdb/xtensa-config.c $TMPDIR/overlay/gdb/gdb
mv $TMPDIR/gdb/xtensa-config.h $TMPDIR/overlay/gdb/include
mv $TMPDIR/gdb/xtensa-modules.c $TMPDIR/overlay/gdb/bfd
mv $TMPDIR/gdb/xtensa-xtregs.c $TMPDIR/overlay/gdb/gdb/gdbserver
mv $TMPDIR/gdb/reg-xtensa.dat $TMPDIR/overlay/gdb/gdb/regformats
tar czf xtensa-overlay.tgz -C $TMPDIR/overlay/ binutils gcc gdb
rm -fr $TMPDIR

Example Files

The following files are the original and generated overlay file for the DC_D_233L processor.

• http://www.linux-xtensa.org/pub/xtensa-config-overlay.tar.gz - Original overlay file provided by Tensilica
• http://www.linux-xtensa.org/pub/xtensa-overlay.tgz - : Generated overlay file, applicable to buildroot and crosstool-NG