cpu_interface: select_triple silently returns None

[JohnSully]

Related to this change here:
b528a00

Instead of a useful error message compilation fails with:
File "core_nopll.py", line 247, in
main()
File "core_nopll.py", line 226, in main
vns = builder.build(build_name="litedram_core", regular_comb=False)
File "/home/john/repos/litex/litex/soc/integration/builder.py", line 156, in build
self._generate_includes()
File "/home/john/repos/litex/litex/soc/integration/builder.py", line 72, in _generate_includes
define(k, v)
File "/home/john/repos/litex/litex/soc/integration/builder.py", line 70, in define
variables_contents.append("{}={}\n".format(k, _makefile_escape(v)))
File "/home/john/repos/litex/litex/soc/integration/builder.py", line 27, in _makefile_escape
return s.replace("\", "\\")
AttributeError: 'NoneType' object has no attribute 'replace'

[JohnSully]

Note: you get this when it can't find the toolchain. It should give an error message saying that like the old code did.

[enjoy-digital]

Thanks, i don't see how you get this, can you provide a minimal code to reproduce?

[JohnSully]

Remove your riscV compiler/tool chains from your PATH or otherwise prevent litex from finding them. Then try to build a litex SoC with a picorv32.

…

On Sat, Oct 6, 2018 at 1:55 AM enjoy-digital ***@***.***> wrote: Thanks, i don't see how you get this, can you provide a minimal code to reproduce? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#115 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADtuArp7kJdNmQkEgE3TpGrjxijh7vcYks5uiEW4gaJpZM4XK5kL> .

[JohnSully]

Also for full explicitness, the expected behavior in this case is an error message saying it can't find the toolchain. The original code used to have a mechanism for that.

[enjoy-digital]

Fixed via 3b27d2a.