x/build: builders for alternate buildmodes?

[crawshaw]

For -buildmode=shared on linux/386, @mwhudson's current set of patches would borrow the CX register. This seems reasonable to me, but means that assembly that works under -buildmode=exe will not work under -buildmode=shared (see the discussion on http://golang.org/cl/16385).

Should we have a builder that runs the standard library tests compiled with -buildmode=shared? What about c-shared and c-archive?

cc @ianlancetaylor @bradfitz

[mwhudson]

More automated testing of this sort of thing would definitely be a good thing. You can't just run "go test -buildmode=shared std" though because -buildmode=shared doesn't make an executable. I guess it would make sense to build a minimal libruntime.so and run tests for all std library things apart from runtime (you can't really say go test -linkshared foo when foo is built into a shared library).

Running go -test -buildmode=pie would be useful.

Something like https://go-review.googlesource.com/#/c/16343/ would be nice too.

[bradfitz]

I have no objections. Any concrete proposal for x/build/dashboard/builders.go etc?

[gopherbot]

CL https://golang.org/cl/17032 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17051 mentions this issue.