Skip to content

[AIX] Fix XCOFF metadata #118905

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Dec 18, 2023
Merged

[AIX] Fix XCOFF metadata #118905

Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
14e6f3f
Fix XCOFF metadata
Dec 13, 2023
ce9a02e
Address comment
Dec 14, 2023
a8e1da3
Address comment
bzEq Dec 18, 2023
File filter

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 14 additions & 10 deletions compiler/rustc_codegen_ssa/src/back/metadata.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -158,12 +158,13 @@ pub(super) fn get_metadata_xcoff<'a>(path: &Path, data: &'a [u8]) -> Result<&'a
file.symbols().find(|sym| sym.name() == Ok(AIX_METADATA_SYMBOL_NAME))
{
let offset = metadata_symbol.address() as usize;
if offset < 8 {
// The offset specifies the location of rustc metadata in the .info section of XCOFF.
// Each string stored in .info section of XCOFF is preceded by a 4-byte length field.
if offset < 4 {
return Err(format!("Invalid metadata symbol offset: {offset}"));
}
// The offset specifies the location of rustc metadata in the comment section.
// The metadata is preceded by a 8-byte length field.
let len = u64::from_le_bytes(info_data[(offset - 8)..offset].try_into().unwrap()) as usize;
// XCOFF format uses big-endian byte order.
let len = u32::from_be_bytes(info_data[(offset - 4)..offset].try_into().unwrap()) as usize;
if offset + len > (info_data.len() as usize) {
return Err(format!(
"Metadata at offset {offset} with size {len} is beyond .info section"
Expand Down Expand Up @@ -478,9 +479,12 @@ pub fn create_wrapper_file(
file.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text);
file.section_mut(section).flags =
SectionFlags::Xcoff { s_flags: xcoff::STYP_INFO as u32 };

let len = data.len() as u64;
let offset = file.append_section_data(section, &len.to_le_bytes(), 1);
// Encode string stored in .info section of XCOFF.
// FIXME: The length of data here is not guaranteed to fit in a u32.
// We may have to split the data into multiple pieces in order to
// store in .info section.
let len: u32 = data.len().try_into().unwrap();
let offset = file.append_section_data(section, &len.to_be_bytes(), 1);
// Add a symbol referring to the data in .info section.
file.add_symbol(Symbol {
name: AIX_METADATA_SYMBOL_NAME.into(),
Expand Down Expand Up @@ -599,12 +603,12 @@ pub fn create_compressed_metadata_file_for_xcoff(
section: SymbolSection::Section(data_section),
flags: SymbolFlags::None,
});
let len = data.len() as u64;
let offset = file.append_section_data(section, &len.to_le_bytes(), 1);
let len = data.len() as u32;
Copy link
Member

@saethlin saethlin Dec 13, 2023 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The length of data here is not guaranteed to fit in a u32. Ideally we'd produce a compile error here, but it's not clear to me if we have access to a TyCtxt to do that. At the very least we should use .try_into().unwrap() to ICE early instead of producing a truncated metadata section.
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

At the very least there is a session:

rust/compiler/rustc_codegen_ssa/src/back/metadata.rs

Line 535 in 14e6f3f

return create_compressed_metadata_file_for_xcoff(file, &packed_metadata, symbol_name);

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@bzEq even though we panic above, this should also be .try_into().unwrap()
let offset = file.append_section_data(section, &len.to_be_bytes(), 1);
// Add a symbol referring to the rustc metadata.
file.add_symbol(Symbol {
name: AIX_METADATA_SYMBOL_NAME.into(),
value: offset + 8, // The metadata is preceded by a 8-byte length field.
value: offset + 4, // The metadata is preceded by a 4-byte length field.
size: 0,
kind: SymbolKind::Unknown,
scope: SymbolScope::Dynamic,
Expand Down