diff --git a/compiler/rustc_codegen_ssa/Cargo.toml b/compiler/rustc_codegen_ssa/Cargo.toml index 0ac12d32be5..984efa21044 100644 --- a/compiler/rustc_codegen_ssa/Cargo.toml +++ b/compiler/rustc_codegen_ssa/Cargo.toml @@ -48,7 +48,7 @@ libc = "0.2.50" [dependencies.object] version = "0.31.1" default-features = false -features = ["read_core", "elf", "macho", "pe", "unaligned", "archive", "write"] +features = ["read_core", "elf", "macho", "pe", "xcoff", "unaligned", "archive", "write"] [target.'cfg(windows)'.dependencies.windows] version = "0.48.0" diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs index 8bf84772f08..9f0ca3863bb 100644 --- a/compiler/rustc_codegen_ssa/src/back/metadata.rs +++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs @@ -6,8 +6,8 @@ use object::write::{self, StandardSegment, Symbol, SymbolSection}; use object::{ - elf, pe, Architecture, BinaryFormat, Endianness, FileFlags, Object, ObjectSection, - SectionFlags, SectionKind, SymbolFlags, SymbolKind, SymbolScope, + elf, pe, xcoff, Architecture, BinaryFormat, Endianness, FileFlags, Object, ObjectSection, + ObjectSymbol, SectionFlags, SectionKind, SymbolFlags, SymbolKind, SymbolScope, }; use snap::write::FrameEncoder; @@ -35,6 +35,8 @@ #[derive(Debug)] pub struct DefaultMetadataLoader; +static AIX_METADATA_SYMBOL_NAME: &'static str = "__aix_rust_metadata"; + fn load_metadata_with( path: &Path, f: impl for<'a> FnOnce(&'a [u8]) -> Result<&'a [u8], String>, @@ -48,7 +50,7 @@ fn load_metadata_with( } impl MetadataLoader for DefaultMetadataLoader { - fn get_rlib_metadata(&self, _target: &Target, path: &Path) -> Result { + fn get_rlib_metadata(&self, target: &Target, path: &Path) -> Result { load_metadata_with(path, |data| { let archive = object::read::archive::ArchiveFile::parse(&*data) .map_err(|e| format!("failed to parse rlib '{}': {}", path.display(), e))?; @@ -60,7 +62,11 @@ fn get_rlib_metadata(&self, _target: &Target, path: &Path) -> Result Result Result { - load_metadata_with(path, |data| search_for_section(path, data, ".rustc")) + fn get_dylib_metadata(&self, target: &Target, path: &Path) -> Result { + if target.is_like_aix { + load_metadata_with(path, |data| get_metadata_xcoff(path, data)) + } else { + load_metadata_with(path, |data| search_for_section(path, data, ".rustc")) + } } } @@ -141,6 +151,33 @@ fn add_gnu_property_note( file.append_section_data(section, &data, 8); } +pub(super) fn get_metadata_xcoff<'a>(path: &Path, data: &'a [u8]) -> Result<&'a [u8], String> { + let Ok(file) = object::File::parse(data) else { + return Ok(data); + }; + let info_data = search_for_section(path, data, ".info")?; + if let Some(metadata_symbol) = + file.symbols().find(|sym| sym.name() == Ok(AIX_METADATA_SYMBOL_NAME)) + { + let offset = metadata_symbol.address() as usize; + 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 4-byte length field. + 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 {} with size {} is beyond .info section", + offset, len + )); + } + return Ok(&info_data[offset..(offset + len)]); + } else { + return Err(format!("Unable to find symbol {}", AIX_METADATA_SYMBOL_NAME)); + }; +} + pub(crate) fn create_object_file(sess: &Session) -> Option> { let endianness = match sess.target.options.endian { Endian::Little => Endianness::Little, @@ -183,6 +220,8 @@ pub(crate) fn create_object_file(sess: &Session) -> Option { file.section_mut(section).flags = @@ -333,6 +376,30 @@ pub fn create_wrapper_file( file.section_mut(section).flags = SectionFlags::Elf { sh_flags: elf::SHF_EXCLUDE as u64 }; } + BinaryFormat::Xcoff => { + 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 u32; + 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(), + value: offset + 4, + size: 0, + kind: SymbolKind::Unknown, + scope: SymbolScope::Dynamic, + weak: false, + section: SymbolSection::Section(section), + flags: SymbolFlags::Xcoff { + n_sclass: xcoff::C_INFO, + x_smtyp: xcoff::C_HIDEXT, + x_smclas: xcoff::C_HIDEXT, + containing_csect: None, + }, + }); + } _ => {} }; file.append_section_data(section, data, 1); @@ -369,6 +436,9 @@ pub fn create_compressed_metadata_file( let Some(mut file) = create_object_file(sess) else { return compressed.to_vec(); }; + if file.format() == BinaryFormat::Xcoff { + return create_compressed_metadata_file_for_xcoff(file, &compressed, symbol_name); + } let section = file.add_section( file.segment_name(StandardSegment::Data).to_vec(), b".rustc".to_vec(), @@ -398,3 +468,60 @@ pub fn create_compressed_metadata_file( file.write().unwrap() } + +/// * Xcoff - On AIX, custom sections are merged into predefined sections, +/// so custom .rustc section is not preserved during linking. +/// For this reason, we store metadata in predefined .info section, and +/// define a symbol to reference the metadata. To preserve metadata during +/// linking on AIX, we have to +/// 1. Create an empty .text section, a empty .data section. +/// 2. Define an empty symbol named `symbol_name` inside .data section. +/// 3. Define an symbol named `AIX_METADATA_SYMBOL_NAME` referencing +/// data inside .info section. +/// From XCOFF's view, (2) creates a csect entry in the symbol table, the +/// symbol created by (3) is a info symbol for the preceding csect. Thus +/// two symbols are preserved during linking and we can use the second symbol +/// to reference the metadata. +pub fn create_compressed_metadata_file_for_xcoff( + mut file: write::Object<'_>, + data: &[u8], + symbol_name: &str, +) -> Vec { + assert!(file.format() == BinaryFormat::Xcoff); + file.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text); + let data_section = file.add_section(Vec::new(), b".data".to_vec(), SectionKind::Data); + let section = file.add_section(Vec::new(), b".info".to_vec(), SectionKind::Debug); + file.add_file_symbol("lib.rmeta".into()); + file.section_mut(section).flags = SectionFlags::Xcoff { s_flags: xcoff::STYP_INFO as u32 }; + // Add a global symbol to data_section. + file.add_symbol(Symbol { + name: symbol_name.as_bytes().into(), + value: 0, + size: 0, + kind: SymbolKind::Data, + scope: SymbolScope::Dynamic, + weak: true, + section: SymbolSection::Section(data_section), + flags: SymbolFlags::None, + }); + let len = data.len() as u32; + 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 + 4, // The metadata is preceded by a 4-byte length field. + size: 0, + kind: SymbolKind::Unknown, + scope: SymbolScope::Dynamic, + weak: false, + section: SymbolSection::Section(section), + flags: SymbolFlags::Xcoff { + n_sclass: xcoff::C_INFO, + x_smtyp: xcoff::C_HIDEXT, + x_smclas: xcoff::C_HIDEXT, + containing_csect: None, + }, + }); + file.append_section_data(section, data, 1); + file.write().unwrap() +}