rustup binaries should be compiled with `remap-debuginfo = true`

[blixt]

Describe the problem you are trying to solve

When compiling a binary with the following RUSTFLAGS environment variable:

RUSTFLAGS='--remap-path-prefix=/Users/blixt/src/my-project=. --remap-path-prefix=/Users/blixt=~'

it successfully removes all references to my local computer's directory structure in the debug information within the compiled output for Cargo dependencies and the project's binary.

However, some references to my computer's directory remains in the binary build product, and that is anything already compiled by rustup, for example:

/Users/blixt/.rustup/toolchains/1.52.0-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/alloc/layout.rs

This makes the build output dependent on the folder structure of the computer it's compiled on, which makes it a lot harder to create reproducible builds across developers' machines (in my case, the build output is turned into WASM, and these strings create differences in the build output).

Describe the solution you'd like

If rustup compiled using the configuration option remap-debuginfo = true or the flag --remap-path-prefix=FROM=TO then it would be easier to create reproducible builds.

Notes

[rbtcollins]

Rustup doesn't build those files at all: they are downloaded from the rust project builds; this bug belongs on rustc.

[kinnison]

I believe this is related to rust-lang/rust#75362