1 files changed, 426 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/xcoff/section.rs b/third_party/rust/object/src/read/xcoff/section.rs
new file mode 100644
index 0000000000..0944e10c83
--- /dev/null
+++ b/third_party/rust/object/src/read/xcoff/section.rs
@@ -0,0 +1,426 @@
+use core::fmt::Debug;
+use core::{iter, result, slice, str};
+
+use crate::{
+    xcoff, BigEndian as BE, CompressedData, CompressedFileRange, Pod, SectionFlags, SectionKind,
+};
+
+use crate::read::{self, Error, ObjectSection, ReadError, ReadRef, Result, SectionIndex};
+
+use super::{AuxHeader, FileHeader, Rel, XcoffFile, XcoffRelocationIterator};
+
+/// An iterator over the sections of an `XcoffFile32`.
+pub type XcoffSectionIterator32<'data, 'file, R = &'data [u8]> =
+    XcoffSectionIterator<'data, 'file, xcoff::FileHeader32, R>;
+/// An iterator over the sections of an `XcoffFile64`.
+pub type XcoffSectionIterator64<'data, 'file, R = &'data [u8]> =
+    XcoffSectionIterator<'data, 'file, xcoff::FileHeader64, R>;
+
+/// An iterator over the sections of an `XcoffFile`.
+#[derive(Debug)]
+pub struct XcoffSectionIterator<'data, 'file, Xcoff, R = &'data [u8]>
+where
+    Xcoff: FileHeader,
+    R: ReadRef<'data>,
+{
+    pub(super) file: &'file XcoffFile<'data, Xcoff, R>,
+    pub(super) iter: iter::Enumerate<slice::Iter<'data, Xcoff::SectionHeader>>,
+}
+
+impl<'data, 'file, Xcoff, R> Iterator for XcoffSectionIterator<'data, 'file, Xcoff, R>
+where
+    Xcoff: FileHeader,
+    R: ReadRef<'data>,
+{
+    type Item = XcoffSection<'data, 'file, Xcoff, R>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|(index, section)| XcoffSection {
+            index: SectionIndex(index),
+            file: self.file,
+            section,
+        })
+    }
+}
+
+/// A section of an `XcoffFile32`.
+pub type XcoffSection32<'data, 'file, R = &'data [u8]> =
+    XcoffSection<'data, 'file, xcoff::FileHeader32, R>;
+/// A section of an `XcoffFile64`.
+pub type XcoffSection64<'data, 'file, R = &'data [u8]> =
+    XcoffSection<'data, 'file, xcoff::FileHeader64, R>;
+
+/// A section of an `XcoffFile`.
+#[derive(Debug)]
+pub struct XcoffSection<'data, 'file, Xcoff, R = &'data [u8]>
+where
+    'data: 'file,
+    Xcoff: FileHeader,
+    R: ReadRef<'data>,
+{
+    pub(super) file: &'file XcoffFile<'data, Xcoff, R>,
+    pub(super) section: &'data Xcoff::SectionHeader,
+    pub(super) index: SectionIndex,
+}
+
+impl<'data, 'file, Xcoff: FileHeader, R: ReadRef<'data>> XcoffSection<'data, 'file, Xcoff, R> {
+    fn bytes(&self) -> Result<&'data [u8]> {
+        self.section
+            .data(self.file.data)
+            .read_error("Invalid XCOFF section offset or size")
+    }
+}
+
+impl<'data, 'file, Xcoff, R> read::private::Sealed for XcoffSection<'data, 'file, Xcoff, R>
+where
+    Xcoff: FileHeader,
+    R: ReadRef<'data>,
+{
+}
+
+impl<'data, 'file, Xcoff, R> ObjectSection<'data> for XcoffSection<'data, 'file, Xcoff, R>
+where
+    Xcoff: FileHeader,
+    R: ReadRef<'data>,
+{
+    type RelocationIterator = XcoffRelocationIterator<'data, 'file, Xcoff, R>;
+
+    fn index(&self) -> SectionIndex {
+        self.index
+    }
+
+    fn address(&self) -> u64 {
+        self.section.s_paddr().into()
+    }
+
+    fn size(&self) -> u64 {
+        self.section.s_size().into()
+    }
+
+    fn align(&self) -> u64 {
+        // The default section alignment is 4.
+        if let Some(aux_header) = self.file.aux_header {
+            match self.kind() {
+                SectionKind::Text => aux_header.o_algntext().into(),
+                SectionKind::Data => aux_header.o_algndata().into(),
+                _ => 4,
+            }
+        } else {
+            4
+        }
+    }
+
+    fn file_range(&self) -> Option<(u64, u64)> {
+        self.section.file_range()
+    }
+
+    fn data(&self) -> Result<&'data [u8]> {
+        self.bytes()
+    }
+
+    fn data_range(&self, address: u64, size: u64) -> Result<Option<&'data [u8]>> {
+        Ok(read::util::data_range(
+            self.bytes()?,
+            self.address(),
+            address,
+            size,
+        ))
+    }
+
+    fn compressed_file_range(&self) -> Result<CompressedFileRange> {
+        Ok(CompressedFileRange::none(self.file_range()))
+    }
+
+    fn compressed_data(&self) -> Result<CompressedData<'data>> {
+        self.data().map(CompressedData::none)
+    }
+
+    fn name_bytes(&self) -> read::Result<&[u8]> {
+        Ok(self.section.name())
+    }
+
+    fn name(&self) -> read::Result<&str> {
+        let name = self.name_bytes()?;
+        str::from_utf8(name)
+            .ok()
+            .read_error("Non UTF-8 XCOFF section name")
+    }
+
+    fn segment_name_bytes(&self) -> Result<Option<&[u8]>> {
+        Ok(None)
+    }
+
+    fn segment_name(&self) -> Result<Option<&str>> {
+        Ok(None)
+    }
+
+    fn kind(&self) -> SectionKind {
+        let section_type = self.section.s_flags() as u16;
+        if section_type & xcoff::STYP_TEXT != 0 {
+            SectionKind::Text
+        } else if section_type & xcoff::STYP_DATA != 0 {
+            SectionKind::Data
+        } else if section_type & xcoff::STYP_TDATA != 0 {
+            SectionKind::Tls
+        } else if section_type & xcoff::STYP_BSS != 0 {
+            SectionKind::UninitializedData
+        } else if section_type & xcoff::STYP_TBSS != 0 {
+            SectionKind::UninitializedTls
+        } else if section_type & (xcoff::STYP_DEBUG | xcoff::STYP_DWARF) != 0 {
+            SectionKind::Debug
+        } else if section_type & (xcoff::STYP_LOADER | xcoff::STYP_OVRFLO) != 0 {
+            SectionKind::Metadata
+        } else if section_type
+            & (xcoff::STYP_INFO | xcoff::STYP_EXCEPT | xcoff::STYP_PAD | xcoff::STYP_TYPCHK)
+            != 0
+        {
+            SectionKind::Other
+        } else {
+            SectionKind::Unknown
+        }
+    }
+
+    fn relocations(&self) -> Self::RelocationIterator {
+        let rel = self.section.relocations(self.file.data).unwrap_or(&[]);
+        XcoffRelocationIterator {
+            file: self.file,
+            relocations: rel.iter(),
+        }
+    }
+
+    fn flags(&self) -> SectionFlags {
+        SectionFlags::Xcoff {
+            s_flags: self.section.s_flags(),
+        }
+    }
+
+    fn uncompressed_data(&self) -> Result<alloc::borrow::Cow<'data, [u8]>> {
+        self.compressed_data()?.decompress()
+    }
+}
+
+/// The table of section headers in an XCOFF file.
+#[derive(Debug, Clone, Copy)]
+pub struct SectionTable<'data, Xcoff: FileHeader> {
+    sections: &'data [Xcoff::SectionHeader],
+}
+
+impl<'data, Xcoff> Default for SectionTable<'data, Xcoff>
+where
+    Xcoff: FileHeader,
+{
+    fn default() -> Self {
+        Self { sections: &[] }
+    }
+}
+
+impl<'data, Xcoff> SectionTable<'data, Xcoff>
+where
+    Xcoff: FileHeader,
+{
+    /// Parse the section table.
+    ///
+    /// `data` must be the entire file data.
+    /// `offset` must be after the optional file header.
+    pub fn parse<R: ReadRef<'data>>(header: &Xcoff, data: R, offset: &mut u64) -> Result<Self> {
+        let section_num = header.f_nscns();
+        if section_num == 0 {
+            return Ok(SectionTable::default());
+        }
+        let sections = data
+            .read_slice(offset, section_num as usize)
+            .read_error("Invalid XCOFF section headers")?;
+        Ok(SectionTable { sections })
+    }
+
+    /// Iterate over the section headers.
+    #[inline]
+    pub fn iter(&self) -> slice::Iter<'data, Xcoff::SectionHeader> {
+        self.sections.iter()
+    }
+
+    /// Return true if the section table is empty.
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.sections.is_empty()
+    }
+
+    /// The number of section headers.
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.sections.len()
+    }
+
+    /// Return the section header at the given index.
+    pub fn section(&self, index: SectionIndex) -> read::Result<&'data Xcoff::SectionHeader> {
+        self.sections
+            .get(index.0)
+            .read_error("Invalid XCOFF section index")
+    }
+}
+
+/// A trait for generic access to `SectionHeader32` and `SectionHeader64`.
+#[allow(missing_docs)]
+pub trait SectionHeader: Debug + Pod {
+    type Word: Into<u64>;
+    type HalfWord: Into<u32>;
+    type Xcoff: FileHeader<SectionHeader = Self, Word = Self::Word>;
+    type Rel: Rel<Word = Self::Word>;
+
+    fn s_name(&self) -> &[u8; 8];
+    fn s_paddr(&self) -> Self::Word;
+    fn s_vaddr(&self) -> Self::Word;
+    fn s_size(&self) -> Self::Word;
+    fn s_scnptr(&self) -> Self::Word;
+    fn s_relptr(&self) -> Self::Word;
+    fn s_lnnoptr(&self) -> Self::Word;
+    fn s_nreloc(&self) -> Self::HalfWord;
+    fn s_nlnno(&self) -> Self::HalfWord;
+    fn s_flags(&self) -> u32;
+
+    /// Return the section name.
+    fn name(&self) -> &[u8] {
+        let sectname = &self.s_name()[..];
+        match memchr::memchr(b'\0', sectname) {
+            Some(end) => &sectname[..end],
+            None => sectname,
+        }
+    }
+
+    /// Return the offset and size of the section in the file.
+    fn file_range(&self) -> Option<(u64, u64)> {
+        Some((self.s_scnptr().into(), self.s_size().into()))
+    }
+
+    /// Return the section data.
+    ///
+    /// Returns `Ok(&[])` if the section has no data.
+    /// Returns `Err` for invalid values.
+    fn data<'data, R: ReadRef<'data>>(&self, data: R) -> result::Result<&'data [u8], ()> {
+        if let Some((offset, size)) = self.file_range() {
+            data.read_bytes_at(offset, size)
+        } else {
+            Ok(&[])
+        }
+    }
+
+    /// Read the relocations.
+    fn relocations<'data, R: ReadRef<'data>>(&self, data: R) -> read::Result<&'data [Self::Rel]>;
+}
+
+impl SectionHeader for xcoff::SectionHeader32 {
+    type Word = u32;
+    type HalfWord = u16;
+    type Xcoff = xcoff::FileHeader32;
+    type Rel = xcoff::Rel32;
+
+    fn s_name(&self) -> &[u8; 8] {
+        &self.s_name
+    }
+
+    fn s_paddr(&self) -> Self::Word {
+        self.s_paddr.get(BE)
+    }
+
+    fn s_vaddr(&self) -> Self::Word {
+        self.s_vaddr.get(BE)
+    }
+
+    fn s_size(&self) -> Self::Word {
+        self.s_size.get(BE)
+    }
+
+    fn s_scnptr(&self) -> Self::Word {
+        self.s_scnptr.get(BE)
+    }
+
+    fn s_relptr(&self) -> Self::Word {
+        self.s_relptr.get(BE)
+    }
+
+    fn s_lnnoptr(&self) -> Self::Word {
+        self.s_lnnoptr.get(BE)
+    }
+
+    fn s_nreloc(&self) -> Self::HalfWord {
+        self.s_nreloc.get(BE)
+    }
+
+    fn s_nlnno(&self) -> Self::HalfWord {
+        self.s_nlnno.get(BE)
+    }
+
+    fn s_flags(&self) -> u32 {
+        self.s_flags.get(BE)
+    }
+
+    /// Read the relocations in a XCOFF32 file.
+    ///
+    /// `data` must be the entire file data.
+    fn relocations<'data, R: ReadRef<'data>>(&self, data: R) -> read::Result<&'data [Self::Rel]> {
+        let reloc_num = self.s_nreloc() as usize;
+        // TODO: If more than 65,534 relocation entries are required, the field value will be 65535,
+        // and an STYP_OVRFLO section header will contain the actual count of relocation entries in
+        // the s_paddr field.
+        if reloc_num == 65535 {
+            return Err(Error("Overflow section is not supported yet."));
+        }
+        data.read_slice_at(self.s_relptr().into(), reloc_num)
+            .read_error("Invalid XCOFF relocation offset or number")
+    }
+}
+
+impl SectionHeader for xcoff::SectionHeader64 {
+    type Word = u64;
+    type HalfWord = u32;
+    type Xcoff = xcoff::FileHeader64;
+    type Rel = xcoff::Rel64;
+
+    fn s_name(&self) -> &[u8; 8] {
+        &self.s_name
+    }
+
+    fn s_paddr(&self) -> Self::Word {
+        self.s_paddr.get(BE)
+    }
+
+    fn s_vaddr(&self) -> Self::Word {
+        self.s_vaddr.get(BE)
+    }
+
+    fn s_size(&self) -> Self::Word {
+        self.s_size.get(BE)
+    }
+
+    fn s_scnptr(&self) -> Self::Word {
+        self.s_scnptr.get(BE)
+    }
+
+    fn s_relptr(&self) -> Self::Word {
+        self.s_relptr.get(BE)
+    }
+
+    fn s_lnnoptr(&self) -> Self::Word {
+        self.s_lnnoptr.get(BE)
+    }
+
+    fn s_nreloc(&self) -> Self::HalfWord {
+        self.s_nreloc.get(BE)
+    }
+
+    fn s_nlnno(&self) -> Self::HalfWord {
+        self.s_nlnno.get(BE)
+    }
+
+    fn s_flags(&self) -> u32 {
+        self.s_flags.get(BE)
+    }
+
+    /// Read the relocations in a XCOFF64 file.
+    ///
+    /// `data` must be the entire file data.
+    fn relocations<'data, R: ReadRef<'data>>(&self, data: R) -> read::Result<&'data [Self::Rel]> {
+        data.read_slice_at(self.s_relptr(), self.s_nreloc() as usize)
+            .read_error("Invalid XCOFF relocation offset or number")
+    }
+}