Add 32-bit and 64-bit stderr/stdout files for ui tests

[oli-obk]

Proposal

Similarly to how mir-opt tests can generate an output file for each bit width, we would allow ui tests to do the same for its stderr/stdout dump files. This would be entirely opt-in, so all ui tests keep behaving as they do now, but if you add

// emit-stderr-for-each-bitwidth

to the test file, then you get a .64bit.stderr file instead of a plain .stderr file. When you run the test on 32 bit you get a .32bit.stderr file. Only the file for your platform is tested, so you need to rerun the test with --target i686-unknown-linux-gnu on a 64 bit host in order to check the 32 bit test file.

The reason I am suggesting this is that it's nearly impossible to specify a useful normalization regex for rust-lang/rust#76881 . The point is to test the output, ideally for each platform individually.

Mentors or Reviewers

• @oli-obk

Process

The main points of the Major Change Process is as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[estebank]

@rustbot second

[oli-obk]

This has been implemented in rust-lang/rust#81817 now