When an archive fails to build, print the path

[tgross35]

Currently the output on failure is as follows:

   Compiling block-buffer v0.10.4
   Compiling crypto-common v0.1.6
   Compiling digest v0.10.7
   Compiling sha2 v0.10.8
   Compiling xz2 v0.1.7
error: failed to build archive: No such file or directory

error: could not compile `bootstrap` (lib) due to 1 previous error

Change this to print which file is being constructed, to give some hint about what is going on.

error: failed to build archive at `path/to/output`: No such file or directory

[rustbot]

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[tgross35]

Unfortunately I have no easy way to test this because I can't build stage1 on the platform where the error happens 😠.

This PR only helps if it is failing because it can't find the output directory. The other possibility is a failure in one of these

rust/compiler/rustc_codegen_llvm/src/back/archive.rs

Lines 365 to 373 in 16b5690

	let path = CString::new(path.to_str().unwrap())?;
	let name = CString::new(name_in_archive.as_bytes())?;
	members.push(llvm::LLVMRustArchiveMemberNew(
	path.as_ptr(),
	name.as_ptr(),
	None,
	));
	strings.push(path);
	strings.push(name);

Open to suggestions for what would work better here, but I think even just this message should help narrow things down.

[BoxyUwU]

Where is the failure from? You said you cant test this but you must have gotten the output in the PR description from somewhere right?

[tgross35]

This was from trying to run ./x inside the aarch64-gnu docker container on aarch64 macos, a bit more context here #127828 (comment). Very open to suggestions to trace that back further since I didn't dig too deep, this PR is just meant to hopefully give some hint.

[BoxyUwU]

@bors r+

feels a bit weird but I don't think it can really hurt, if someone else has opinions here feel free to take over 🤷‍♀️

[bors]

📌 Commit e0af3c6 has been approved by BoxyUwU

It is now in the queue for this repository.

[tgross35]

feels a bit weird but I don't think it can really hurt, if someone else has opinions here feel free to take over 🤷‍♀️

My feelings exactly. Thanks!