bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #83682 - bjorn3:mmap_wrapper, r=cjgillot

Browse source 
Add an Mmap wrapper to rustc_data_structures

This wrapper implements StableAddress and falls back to directly reading the file on wasm32.

Taken from #83640, which I will close due to the perf regression.
This commit is contained in:
bors 2021-04-03 13:23:42 +00:00
commit 97717a5618
12 changed files with 63 additions and 50 deletions
Download patch file Download diff file Expand all files Collapse all files

1
compiler/rustc_metadata/Cargo.toml
View file

@ -11,7 +11,6 @@ doctest = false
libc = "0.2"
snap = "1"
tracing = "0.1"
memmap2 = "0.2.1"
smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
rustc_middle = { path = "../rustc_middle" }
rustc_attr = { path = "../rustc_attr" }

19
compiler/rustc_metadata/src/locator.rs
View file

@ -216,6 +216,7 @@ use crate::creader::Library;
use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER};
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::memmap::Mmap;
use rustc_data_structures::owning_ref::OwningRef;
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::MetadataRef;
@ -232,7 +233,6 @@ use rustc_target::spec::{Target, TargetTriple};
use snap::read::FrameDecoder;
use std::io::{Read, Result as IoResult, Write};
use std::ops::Deref;
use std::path::{Path, PathBuf};
use std::{cmp, fmt, fs};
use tracing::{debug, info, warn};
@ -727,19 +727,6 @@ impl<'a> CrateLocator<'a> {
}
}
/// A trivial wrapper for `Mmap` that implements `StableDeref`.
struct StableDerefMmap(memmap2::Mmap);
impl Deref for StableDerefMmap {
type Target = [u8];
fn deref(&self) -> &[u8] {
self.0.deref()
}
}
unsafe impl stable_deref_trait::StableDeref for StableDerefMmap {}
fn get_metadata_section(
target: &Target,
flavor: CrateFlavor,
@ -779,11 +766,11 @@ fn get_metadata_section(
// mmap the file, because only a small fraction of it is read.
let file = std::fs::File::open(filename)
.map_err(|_| format!("failed to open rmeta metadata: '{}'", filename.display()))?;
let mmap = unsafe { memmap2::Mmap::map(&file) };
let mmap = unsafe { Mmap::map(file) };
let mmap = mmap
.map_err(|_| format!("failed to mmap rmeta metadata: '{}'", filename.display()))?;
rustc_erase_owner!(OwningRef::new(StableDerefMmap(mmap)).map_owner_box())
rustc_erase_owner!(OwningRef::new(mmap).map_owner_box())
}
};
let blob = MetadataBlob::new(raw_bytes);