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| author | Manish Goregaokar <manishsmail@gmail.com> | 2021-10-05 12:52:49 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-10-05 12:52:49 -0700 |
| commit | 5f8b1614d110fc3f0cd8536e08822a8cead32172 (patch) | |
| tree | 411ef5015faad89dc56928c2040b47fd2cff070f /compiler | |
| parent | f71b3e2b46505fda8dea7187fa90b80472f7abfa (diff) | |
| parent | c35a700be2aebc0449a16fa1a09d7667aa209230 (diff) | |
| download | rust-5f8b1614d110fc3f0cd8536e08822a8cead32172.tar.gz rust-5f8b1614d110fc3f0cd8536e08822a8cead32172.zip | |
Rollup merge of #89546 - joshtriplett:grow-metadata-faster, r=petrochenkov
Make an initial guess for metadata size to reduce buffer resizes When reading metadata, the compiler starts with a `Vec::new()`, which will need to grow repeatedly as the metadata gets decompressed into it. Reduce the number of resizes by starting out at the size of the compressed data.
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_metadata/src/locator.rs | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/compiler/rustc_metadata/src/locator.rs b/compiler/rustc_metadata/src/locator.rs index abdac78ae24..9b1ea3b4c4c 100644 --- a/compiler/rustc_metadata/src/locator.rs +++ b/compiler/rustc_metadata/src/locator.rs @@ -740,7 +740,9 @@ fn get_metadata_section( // Header is okay -> inflate the actual metadata let compressed_bytes = &buf[header_len..]; debug!("inflating {} bytes of compressed metadata", compressed_bytes.len()); - let mut inflated = Vec::new(); + // Assume the decompressed data will be at least the size of the compressed data, so we + // don't have to grow the buffer as much. + let mut inflated = Vec::with_capacity(compressed_bytes.len()); match FrameDecoder::new(compressed_bytes).read_to_end(&mut inflated) { Ok(_) => rustc_erase_owner!(OwningRef::new(inflated).map_owner_box()), Err(_) => { |