linux - how to change the host type for a 'Canadian cross' compilation of GCC with crosstool-NG

Question

I've installed crosstool-NG and built GCC on a host+build x86 machine that targets arm-unknown-linux-gnueabi. I've then used arm-unknown-linux-gnueabi-gcc to compile a program that ran well on my ARM board.

I'm wanting to now build GCC, targeting ARM to be hosted on ARM. I believe the lingo is

build=i486-pc-linux-gnu
target=arm-unknown-linux-gnueabi-gcc
host=arm-unknown-linux-gnueabi-gcc

How do I do this? do I run ./configure for crosstool-NG passing --host=arm-unknown-linux-gnueabi-gcc?

or do I change the environment variables for CC/etc?

Answer 1

You do this with a .config file. I think samples with a comma in the name are good ones to look at. The main difference is that you must run ct-ng multiple times to create several cross compilers.

ct-ng has under went some changes in Canadian crosses lately. However, you will probably need to re-use your original cross compiler that runs on the PC. The reason is that a compiler will include libraries compiled for the ARM and you need to generate these libraries on your PC. Generally, ensure that the iX86-host+ARM-target compiler is on your path. Then you must set the host tuple or prefix for this tool chain in the toolchain menu. You need set the build tuple to the same compiler.

ct-ng help | grep variables

This gives a directory with a bunch of text files that you can grep for hints.

See 6 - Toolchain types.txt for example. Cross-native or Canadian-cross really doesn't matter, in terms of complexity of building. You need only one intermediate for Cross native, but you need two intermediate compilers for a Canadian cross.

Edit: Ct-ng's How a compiler is constructed has some information on all the happening.