Missing function names (due to overlapping unit ranges?) on debug files of ls

[mstange]

Updating the addr2line dependency in samply caused test failures, see mstange/samply#310 .

Steps to reproduce:

1. Have a checkout of the samply repo next to your checkout of this addr2line repo.
2. Run the following from the root of the addr2line repo: cargo run --features bin --bin addr2line -- -pCfi -e ../samply/fixtures/other/ls-linux/260a3e6e46db57abf718f6a3562c6eedccf269.debug --sup ../samply/fixtures/other/ls-linux/coreutils.debug 0xd6f4

Expected results:

It should print

do_lstat at ./src/ls.c:1184
 (inlined by) gobble_file at ./src/ls.c:3403

Actual results:

It now prints

gobble_file.constprop.0 at ./src/ls.c:1184

---

This is a regression from #306.

Logging the unit ranges just before the unit_ranges.sort_by_key(|i| i.range.end); call gives the following:

[src/unit.rs:354:9] &mut unit_ranges = [
    UnitRange {
        unit_id: 0,
        min_begin: 0,
        range: Range {
            begin: 15296,
            end: 22632,
        },
    },
    UnitRange {
        unit_id: 0,
        min_begin: 0,
        range: Range {
            begin: 22944,
            end: 68112,
        },
    },
    UnitRange {
        unit_id: 68,
        min_begin: 0,
        range: Range {
            begin: 22944,
            end: 68112,
        },
    },
    UnitRange {
        unit_id: 68,
        min_begin: 0,
        range: Range {
            begin: 15296,
            end: 22632,
        },
    },
    UnitRange {
        unit_id: 69,
        min_begin: 0,
        range: Range {
            begin: 68112,
            end: 84904,
        },
    },
]

It seems that the 22944..68112 range is present twice.

I haven't debugged any further than this.

[philipc]

I'll look into it. This crate needs better tests, maybe I should copy samply's.

[philipc]

The duplicate range is due to a partial unit. Ignoring unit ranges for the partial unit makes it work. It previously worked because the reverse order made us find the compilation unit first. I'm trying to understand more about the partial unit ranges before doing a fix.