bjoernager/rust
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Add an Mmap wrapper to rustc_data_structures

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This wrapper implements StableAddress and falls back to directly reading
the file on wasm32
This commit is contained in:
bjorn3 2021-03-29 11:18:52 +02:00
parent 3aedcf06b7
commit 8331dbe6d0
12 changed files with 56 additions and 50 deletions
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21
compiler/rustc_codegen_cranelift/src/metadata.rs
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@ -1,11 +1,11 @@
//! Reading and writing of the rustc metadata for rlibs and dylibs
use std::fs::File;
use std::ops::Deref;
use std::path::Path;
use rustc_codegen_ssa::METADATA_FILENAME;
use rustc_data_structures::owning_ref::{OwningRef, StableAddress};
use rustc_data_structures::memmap::Mmap;
use rustc_data_structures::owning_ref::OwningRef;
use rustc_data_structures::rustc_erase_owner;
use rustc_data_structures::sync::MetadataRef;
use rustc_middle::middle::cstore::{EncodedMetadata, MetadataLoader};
@ -17,26 +17,13 @@ use crate::backend::WriteMetadata;
pub(crate) struct CraneliftMetadataLoader;
struct StableMmap(memmap2::Mmap);
impl Deref for StableMmap {
type Target = [u8];
fn deref(&self) -> &[u8] {
&*self.0
}
}
unsafe impl StableAddress for StableMmap {}
fn load_metadata_with(
path: &Path,
f: impl for<'a> FnOnce(&'a [u8]) -> Result<&'a [u8], String>,
) -> Result<MetadataRef, String> {
let file = File::open(path).map_err(|e| format!("{:?}", e))?;
let data = unsafe { memmap2::MmapOptions::new().map_copy_read_only(&file) }
.map_err(|e| format!("{:?}", e))?;
let metadata = OwningRef::new(StableMmap(data)).try_map(f)?;
let data = unsafe { Mmap::map(file) }.map_err(|e| format!("{:?}", e))?;
let metadata = OwningRef::new(data).try_map(f)?;
return Ok(rustc_erase_owner!(metadata.map_owner_box()));
}