sysroot spans still not printed, when remap-path-prefix is set with a custom path

[infinity0]

The fix at the end of #53081 talks about remap-debuginfo in config.toml and /rustc/$hash, however in Debian we use --remap-path-prefix in RUSTFLAGS and /usr/src/rustc-$VERSION.

Results in 64 failing tests in [ui], in 1.44.1

@eddyb any ideas for a quick fix?

[infinity0]

This also causes 7 mir-opt-tests to fail, the ones that refer to $SRC_DIR. Example:

------------------------------------------
1       // MIR for `std::intrinsics::drop_in_place` before AddMovesForPackedDrops
2       
3       fn std::intrinsics::drop_in_place(_1: *mut std::vec::Vec<i32>) -> () {
-           let mut _0: ();                      // return place in scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
-           let mut _2: &mut std::vec::Vec<i32>; // in scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
-           let mut _3: ();                      // in scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
+           let mut _0: ();                      // return place in scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
+           let mut _2: &mut std::vec::Vec<i32>; // in scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
+           let mut _3: ();                      // in scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
7       
8           bb0: {
-               goto -> bb7;                     // bb0[0]: scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
+               goto -> bb7;                     // bb0[0]: scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
10          }
11      
12          bb1: {

-               return;                          // bb1[0]: scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
+               return;                          // bb1[0]: scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
14          }
15      
16          bb2 (cleanup): {

-               resume;                          // bb2[0]: scope 0 at $SRC_DIR/libcore/ptr/mod.rs:LL:COL
+               resume;                          // bb2[0]: scope 0 at /usr/src/rustc-1.44.1/src/libcore/ptr/mod.rs:177:1: 181:2
18          }
19      
20          bb3: {

[infinity0]

If it's infeasible to fix this generally in rustc, I'd be happy to keep & maintain a Debian-specific hacky patch.

[infinity0]

If I patch debuginfo_map_to() in src/bootstrap/lib.rs to hardcode our /usr/src/rustc-$VERSION path instead of /rustc/$hash it seems to work.

I was initially thrown off by the documentation of remap-debuginfo:

# Map all debuginfo paths for libstd and crates to `/rust/$sha/$crate/...`,
# generally only set for releases
#remap-debuginfo = false

This suggests that the mapping isn't applied to rustc's own artifacts (in the same way we have a separate debuginfo-level-std), but actually it in fact is applied to everything in src/bootstrap/bin/rustc.rs, which is what we want in Debian. I will file a PR to update the comment.

[nagisa]

Closely related to #73167

[mark-i-m]

Also seeing this in #73265 (comment)