cargo-build-bpf: Add Windows support

[joncinque]

Problem

cargo-build-bpf doesn't support windows

Summary of Changes

Add support for it!

A few notes:

• ld doesn't ship by default with mingw, causing linker not found errors, so one of the changes is to force the usage of ld.lld from the sdk to link. I have very little knowledge of different linker flavors, but this was the only one that worked. If you think it should be another one, please let me know.
• it isn't possible to run bash scripts from the program, since they aren't natively executable by windows. To get around that, this avoids calling strip.sh and just calls llvm-objcopy directly.
• for dump.sh, it's possible to run the script separately, and re-run cargo build-bpf --dump to do the postprocessing step. it isn't elegant, but it actually works!

Fixes #

[dmakarov]

This looks good to me, but I'm not quite sure why the usual CI checks were not executed for this PR. Let's wait until bpf-tools release assets are published ( https://github.com/solana-labs/bpf-tools/actions/runs/1281082328 ) before merging this.

[joncinque]

Sounds good to me! I've nudged a little update to the error message to restart the CI job

Pull request has been modified.

Pull request has been modified.

[dmakarov]

Jon, I had to turn off the build on windows when I released bpf-tools v1.19. The build failed when the build artifacts were copied in preparation for making a package tarball. The reason for the failure was the CI agent ran out of disk space. I'm not sure how to request a bigger disk for a CI agent machine, and so for now CI doesn't build bpf-tools for Windows.

[joncinque]

Ah that's too bad. Thanks for noticing this. It looks like we'll need to move the steps to a different directory for this to work as expected, if actions/runner-images#1341 is actually possible, we can pass in a new out directory to checkout and build everything. I'll take a longer look at this later.

[codecov]

Codecov Report

Merging #20276 (3b0471b) into master (a066466) will decrease coverage by 0.0%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #20276     +/-   ##
=========================================
- Coverage    81.2%    81.2%   -0.1%     
=========================================
  Files         520      520             
  Lines      145949   145949             
=========================================
- Hits       118533   118532      -1     
- Misses      27416    27417      +1     

Pull request has been modified.

[gajojr]

So what is the solution for this?

[TradeUpCards]

So what is the solution for this?

I'd also like to know. Just getting into Solana coding and can't even do Hello World example because it says

no such subcommand: +bpf

Been scouring the web, but seems most people getting it to work are on Linux and not Windows.

[joncinque]

Be sure to install the solana command line tools and rust, then use a bash-compatible shell like Git Bash. If you need more support, please ask in the Solana Stack Exchange https://solana.stackexchange.com/