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target-lexicon OS sometimes doesn't match rustc target jsons

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
rust
Domain
compilers

Research direction

Start by comparing target-lexicon's parsed OS values with rustc target-spec JSON for i686-linux-android and aarch64-apple-darwin, using the rustc command shown in the issue. Read the target parsing and OS-mapping code, then check existing tests for these triples. Done means the intended naming behavior is agreed and the discrepancies are covered by passing regression tests.

Written by the indexing model from the issue text.

Description

I've been playing around with target-lexicon a bit and it seems like while most of the time it is pretty faithful to the rustc target json, some of the time the result diverges.

For example, i686-linux-android has this rustc target JSON:

$ RUSTC_BOOTSTRAP=1 rustc -Z unstable-options --target=i686-linux-android --print target-spec-json
{
  "arch": "x86",
  "cpu": "pentiumpro",
  "data-layout": "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-f80:32-n8:16:32-S128",
  "default-uwtable": true,
  "dwarf-version": 2,
  "dynamic-linking": true,
  "env": "gnu",
  "executables": true,
  "features": "+mmx,+sse,+sse2,+sse3,+ssse3",
  "has-rpath": true,
  "is-builtin": true,
  "llvm-target": "i686-linux-android",
  "max-atomic-width": 64,
  "os": "android",
  "position-independent-executables": true,
  "pre-link-args": {
    "gcc": [
      "-Wl,--allow-multiple-definition"
    ]
  },
  "relro-level": "full",
  "stack-probes": {
    "kind": "call"
  },
  "target-family": [
    "unix"
  ],
  "target-pointer-width": "32"
}

However, target-lexicon parses the same triple as having the OS Linux rather than Android.

Somewhat related, for "aarch64-apple-darwin":

  • rustc has "os": "macos"
  • target-lexicon parses this as Darwin

I'm not sure exactly what behavior is desired here but I thought it might be useful to flag this. Thanks!

Dominant language
Rust
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Forks
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