-use rustc::middle::cstore::MetadataLoader;
-use rustc_data_structures::owning_ref::{self, OwningRef};
-use rustc_data_structures::rustc_erase_owner;
+//! Reading and writing of the rustc metadata for rlibs and dylibs
+
+use std::convert::TryFrom;
use std::fs::File;
use std::path::Path;
-pub const METADATA_FILENAME: &str = "rust.metadata.bin";
+use rustc_codegen_ssa::METADATA_FILENAME;
+use rustc_data_structures::owning_ref::{self, OwningRef};
+use rustc_data_structures::rustc_erase_owner;
+use rustc_middle::middle::cstore::{EncodedMetadata, MetadataLoader};
+use rustc_middle::ty::TyCtxt;
+use rustc_session::config;
+use rustc_target::spec::Target;
+
+use crate::backend::WriteMetadata;
-pub struct CraneliftMetadataLoader;
+pub(crate) struct CraneliftMetadataLoader;
impl MetadataLoader for CraneliftMetadataLoader {
fn get_rlib_metadata(
&self,
- _target: &crate::rustc_target::spec::Target,
+ _target: &Target,
path: &Path,
) -> Result<owning_ref::ErasedBoxRef<[u8]>, String> {
let mut archive = ar::Archive::new(File::open(path).map_err(|e| format!("{:?}", e))?);
while let Some(entry_result) = archive.next_entry() {
let mut entry = entry_result.map_err(|e| format!("{:?}", e))?;
if entry.header().identifier() == METADATA_FILENAME.as_bytes() {
- let mut buf = Vec::new();
+ let mut buf = Vec::with_capacity(
+ usize::try_from(entry.header().size())
+ .expect("Rlib metadata file too big to load into memory."),
+ );
::std::io::copy(&mut entry, &mut buf).map_err(|e| format!("{:?}", e))?;
let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf).into();
return Ok(rustc_erase_owner!(buf.map_owner_box()));
fn get_dylib_metadata(
&self,
- _target: &crate::rustc_target::spec::Target,
- _path: &Path,
+ _target: &Target,
+ path: &Path,
) -> Result<owning_ref::ErasedBoxRef<[u8]>, String> {
- Err("dylib metadata loading is not yet supported".to_string())
+ use object::{Object, ObjectSection};
+ let file = std::fs::read(path).map_err(|e| format!("read:{:?}", e))?;
+ let file = object::File::parse(&file).map_err(|e| format!("parse: {:?}", e))?;
+ let buf = file
+ .section_by_name(".rustc")
+ .ok_or("no .rustc section")?
+ .data()
+ .map_err(|e| format!("failed to read .rustc section: {:?}", e))?
+ .to_owned();
+ let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf).into();
+ Ok(rustc_erase_owner!(buf.map_owner_box()))
+ }
+}
+
+// Adapted from https://github.com/rust-lang/rust/blob/da573206f87b5510de4b0ee1a9c044127e409bd3/src/librustc_codegen_llvm/base.rs#L47-L112
+pub(crate) fn write_metadata<P: WriteMetadata>(
+ tcx: TyCtxt<'_>,
+ product: &mut P,
+) -> EncodedMetadata {
+ use snap::write::FrameEncoder;
+ use std::io::Write;
+
+ #[derive(PartialEq, Eq, PartialOrd, Ord)]
+ enum MetadataKind {
+ None,
+ Uncompressed,
+ Compressed,
}
+
+ let kind = tcx
+ .sess
+ .crate_types()
+ .iter()
+ .map(|ty| match *ty {
+ config::CrateType::Executable
+ | config::CrateType::Staticlib
+ | config::CrateType::Cdylib => MetadataKind::None,
+
+ config::CrateType::Rlib => MetadataKind::Uncompressed,
+
+ config::CrateType::Dylib | config::CrateType::ProcMacro => MetadataKind::Compressed,
+ })
+ .max()
+ .unwrap_or(MetadataKind::None);
+
+ if kind == MetadataKind::None {
+ return EncodedMetadata::new();
+ }
+
+ let metadata = tcx.encode_metadata();
+ if kind == MetadataKind::Uncompressed {
+ return metadata;
+ }
+
+ assert!(kind == MetadataKind::Compressed);
+ let mut compressed = tcx.metadata_encoding_version();
+ FrameEncoder::new(&mut compressed)
+ .write_all(&metadata.raw_data)
+ .unwrap();
+
+ product.add_rustc_section(
+ rustc_middle::middle::exported_symbols::metadata_symbol_name(tcx),
+ compressed,
+ tcx.sess.target.target.options.is_like_osx,
+ );
+
+ metadata
}