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

[Stephen Warren <swarren@wwwdotorg.org>]

On 10/03/2015 08:30 AM, Simon Glass wrote:
> Hi Stephen,
> 
> On 2 October 2015 at 00:27, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> 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
> 
> I wonder if we need an option to specify the full path and avoid the search?
> 
> Maybe [toolchain-prefix] ?

Yes, that sounds like exactly what I was hoping for.