rust/compiler/rustc_interface
Dylan DPC da74a77622
Rollup merge of #82047 - the8472:fast-rename, r=davidtwco
bypass auto_da_alloc for metadata files

This saves about 0.7% when rerunning the UI test suite. I.e. when the metadata files exist and will be overwritten. No improvements expected for a clean build. So it might show up in incr-patched perf results.
```
regular rename:

Benchmark #1: touch src/tools/compiletest/src/main.rs ; RUSTC_WRAPPER="" schedtool -B -e ./x.py test src/test/ui
  Time (mean ± σ):     47.305 s ±  0.170 s    [User: 1631.540 s, System: 412.648 s]
  Range (min … max):   47.125 s … 47.856 s    20 runs

non-durable rename:

Benchmark #1: touch src/tools/compiletest/src/main.rs ; RUSTC_WRAPPER="" schedtool -B -e ./x.py test src/test/ui
  Time (mean ± σ):     46.930 s ±  0.064 s    [User: 1634.344 s, System: 396.038 s]
  Range (min … max):   46.759 s … 47.043 s    20 runs
```

There are more places that trigger auto_da_alloc behavior by overwriting existing files with O_TRUNC, but those are much harder to locate because `O_TRUNC` is set on `open()` but the writeback is triggered on `close()`. The latter is the part which shows up in profiles.
2021-03-08 13:13:18 +01:00
..
src Rollup merge of #82047 - the8472:fast-rename, r=davidtwco 2021-03-08 13:13:18 +01:00
Cargo.toml Move the query system to rustc_query_impl. 2021-02-19 17:51:58 +01:00