Try adding metadata length prefix, and obey it while decoding

This commit is contained in:
Rune Tynan 2023-02-13 12:50:45 -05:00
parent 267cd1d2c5
commit dce3947110
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GPG Key ID: 7ECC932F8B2C731E
3 changed files with 10 additions and 2 deletions

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@ -305,6 +305,7 @@ pub fn create_compressed_metadata_file(
symbol_name: &str,
) -> Vec<u8> {
let mut compressed = rustc_metadata::METADATA_HEADER.to_vec();
compressed.write_all(&(metadata.raw_data().len() as u32).to_be_bytes()).unwrap();
FrameEncoder::new(&mut compressed).write_all(metadata.raw_data()).unwrap();
let Some(mut file) = create_object_file(sess) else {
return compressed.to_vec();

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@ -798,8 +798,15 @@ fn get_metadata_section<'p>(
)));
}
// Length of the compressed stream - this allows linkers to pad the section if they want
let usize_len = core::mem::size_of::<u32>();
let Ok(len_bytes) = <[u8; 4]>::try_from(&buf[header_len..cmp::min(header_len + usize_len, buf.len())]) else {
return Err(MetadataError::LoadFailure("invalid metadata length found".to_string()));
};
let compressed_len = u32::from_be_bytes(len_bytes) as usize;
// Header is okay -> inflate the actual metadata
let compressed_bytes = &buf[header_len..];
let compressed_bytes = &buf[header_len..compressed_len + header_len];
debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
// 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.

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@ -55,7 +55,7 @@ pub(crate) fn rustc_version() -> String {
/// Metadata encoding version.
/// N.B., increment this if you change the format of metadata such that
/// the rustc version can't be found to compare with `rustc_version()`.
const METADATA_VERSION: u8 = 6;
const METADATA_VERSION: u8 = 7;
/// Metadata header which includes `METADATA_VERSION`.
///