[U-Boot] How do I tell buildman to use a /specific/ toolchain?

[Stephen Warren <swarren@wwwdotorg.org>]

On 10/01/2015 04:59 PM, Simon Glass wrote:
> Hi Stephen,
>
> On Wednesday, 23 September 2015, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>
>> Simon,
>>
>> I have 3 different ARM toolchains installed into /usr/bin via distro packages. How do I tell buildman which of those to use?
>>
>> I had originally thought that ~/.buildman's [toolchain] section contained CROSS_COMPILE-like values, so I tried:
>>
>>> [toolchain]
>>> root: /
>>> arm0-not-installed: arm-none-gnueabi-
>>> arm1: arm-none-eabi-
>>> arm2: arm-linux-gnueabihf-
>>> arm3: arm-linux-gnueabi-
>>> arch64: aarch64-linux-gnu-
>>>
>>> [toolchain-alias]
>>> arm: arm1
>>> aarch64: aarch64
>>
>>
>> (I intended to change the "arm: arm1" line to point at arm1/2/3 based on which I wanted to use at a particular time).
>>
>> However, running "buildman --list-toolchains" and re-reading the docs shows me that the [toolchain] values are absolute directories that buildman searches for files named *-gcc:
>>
>>>     - scanning path 'arm-none-gnueabi-'
>>>        - looking in 'arm-none-gnueabi-/.'
>>>        - looking in 'arm-none-gnueabi-/bin'
>>>        - looking in 'arm-none-gnueabi-/usr/bin'
>>
>>
>> If buildman finds multiple toolchains, there doesn't seem to be a way to tell it which one to use. Am I missing something?
>>
>> I suppose a solution wouuld be to move the compiler binaries into different separate directories, and only list one of those directories in ~/.buildman. However, I can't do that for distro-packaged toolchains (well, I suppose I could manually mv everything all over the place, but that's really fragile since it'd break any time the package got upgraded or removed and re-installed).
>>
>> I think it makes sense to add new syntax into ~/.buildman to specify "don't do automagical searching, just use this CROSS_COMPILE value that I say". Does that sound reasonable? Automagic stuff makes for great defaults, but if it can't be overridden, it sucks when you actually know what you want.
>
> Yes I think it would be fine to add an option to use CROSS_COMPILE (of
> course it would fail if you tried to build the board with the wrong
> arch).

I wasn't necessarily looking for buildman to pick up the CROSS_COMPILE 
environment variable, although that would be a simple solution for 
single-arch builds at least. My mention of CROSS_COMPILE immediately 
above was re: using values that are formatted in the same way as the 
CROSS_COMPILE environment variable would be, rather than directory 
names, in the config file. In other words, the example content I showed 
above.

> The option other option at present is -G which lets you use multiple
> .buildman files. You could have one of these for each toolchain.

I don't think that gets me what I want. As far as I can tell, the 
buildman config file contains a list directories to search within, yet 
if I have 3 toolchains in a single directory, there's no way to select 
which one I want to use, is there?

In other words, a config file that contains:

[toolchain]
distro-packages: /usr/bin

... finds the following toolchains:

[swarren at swarren-lx1 u-boot]$ ./tools/buildman/buildman \
	--list-tool-chains
Scanning for tool chains
    - scanning path '/usr/bin'
       - looking in '/usr/bin/.'
          - found '/usr/bin/./arm-linux-gnueabi-gcc'
          - found '/usr/bin/./arm-linux-gnueabihf-gcc'
          - found '/usr/bin/./arm-none-eabi-gcc'
(That's 3 AArch32 toolchains found)
          - found '/usr/bin/./winegcc'
          - found '/usr/bin/./aarch64-linux-gnu-gcc'
          - found '/usr/bin/./gcc'
          - found '/usr/bin/./c89-gcc'
          - found '/usr/bin/./x86_64-linux-gnu-gcc'
          - found '/usr/bin/./i586-mingw32msvc-gcc'
          - found '/usr/bin/./c99-gcc'
       - looking in '/usr/bin/bin'
       - looking in '/usr/bin/usr/bin'
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
Tool chain test:  OK
List of available toolchains (7):
aarch64   : /usr/bin/./aarch64-linux-gnu-gcc
arm       : /usr/bin/./arm-linux-gnueabi-gcc
(Buildman chose that one, and I think I have no control over that?)
c89       : /usr/bin/./c89-gcc
c99       : /usr/bin/./c99-gcc
i586      : /usr/bin/./i586-mingw32msvc-gcc
sandbox   : /usr/bin/./winegcc
x86_64    : /usr/bin/./x86_64-linux-gnu-gcc