Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/addr2line/src/builtin_split_dwarf_loader.rs

@@ -0,0 +1,164 @@
+use alloc::borrow::Cow;
+use alloc::sync::Arc;
+use std::fs::File;
+use std::path::PathBuf;
+
+use object::Object;
+
+use crate::{LookupContinuation, LookupResult};
+
+#[cfg(unix)]
+fn convert_path<R: gimli::Reader<Endian = gimli::RunTimeEndian>>(
+    r: &R,
+) -> Result<PathBuf, gimli::Error> {
+    use std::ffi::OsStr;
+    use std::os::unix::ffi::OsStrExt;
+    let bytes = r.to_slice()?;
+    let s = OsStr::from_bytes(&bytes);
+    Ok(PathBuf::from(s))
+}
+
+#[cfg(not(unix))]
+fn convert_path<R: gimli::Reader<Endian = gimli::RunTimeEndian>>(
+    r: &R,
+) -> Result<PathBuf, gimli::Error> {
+    let bytes = r.to_slice()?;
+    let s = std::str::from_utf8(&bytes).map_err(|_| gimli::Error::BadUtf8)?;
+    Ok(PathBuf::from(s))
+}
+
+fn load_section<'data: 'file, 'file, O, R, F>(
+    id: gimli::SectionId,
+    file: &'file O,
+    endian: R::Endian,
+    loader: &mut F,
+) -> Result<R, gimli::Error>
+where
+    O: object::Object<'data, 'file>,
+    R: gimli::Reader<Endian = gimli::RunTimeEndian>,
+    F: FnMut(Cow<'data, [u8]>, R::Endian) -> R,
+{
+    use object::ObjectSection;
+
+    let data = id
+        .dwo_name()
+        .and_then(|dwo_name| {
+            file.section_by_name(dwo_name)
+                .and_then(|section| section.uncompressed_data().ok())
+        })
+        .unwrap_or(Cow::Borrowed(&[]));
+    Ok(loader(data, endian))
+}
+
+/// A simple builtin split DWARF loader.
+pub struct SplitDwarfLoader<R, F>
+where
+    R: gimli::Reader<Endian = gimli::RunTimeEndian>,
+    F: FnMut(Cow<'_, [u8]>, R::Endian) -> R,
+{
+    loader: F,
+    dwarf_package: Option<gimli::DwarfPackage<R>>,
+}
+
+impl<R, F> SplitDwarfLoader<R, F>
+where
+    R: gimli::Reader<Endian = gimli::RunTimeEndian>,
+    F: FnMut(Cow<'_, [u8]>, R::Endian) -> R,
+{
+    fn load_dwarf_package(loader: &mut F, path: Option<PathBuf>) -> Option<gimli::DwarfPackage<R>> {
+        let mut path = path.map(Ok).unwrap_or_else(std::env::current_exe).ok()?;
+        let dwp_extension = path
+            .extension()
+            .map(|previous_extension| {
+                let mut previous_extension = previous_extension.to_os_string();
+                previous_extension.push(".dwp");
+                previous_extension
+            })
+            .unwrap_or_else(|| "dwp".into());
+        path.set_extension(dwp_extension);
+        let file = File::open(&path).ok()?;
+        let map = unsafe { memmap2::Mmap::map(&file).ok()? };
+        let dwp = object::File::parse(&*map).ok()?;
+
+        let endian = if dwp.is_little_endian() {
+            gimli::RunTimeEndian::Little
+        } else {
+            gimli::RunTimeEndian::Big
+        };
+
+        let empty = loader(Cow::Borrowed(&[]), endian);
+        gimli::DwarfPackage::load(
+            |section_id| load_section(section_id, &dwp, endian, loader),
+            empty,
+        )
+        .ok()
+    }
+
+    /// Create a new split DWARF loader.
+    pub fn new(mut loader: F, path: Option<PathBuf>) -> SplitDwarfLoader<R, F> {
+        let dwarf_package = SplitDwarfLoader::load_dwarf_package(&mut loader, path);
+        SplitDwarfLoader {
+            loader,
+            dwarf_package,
+        }
+    }
+
+    /// Run the provided `LookupResult` to completion, loading any necessary
+    /// split DWARF along the way.
+    pub fn run<L>(&mut self, mut l: LookupResult<L>) -> L::Output
+    where
+        L: LookupContinuation<Buf = R>,
+    {
+        loop {
+            let (load, continuation) = match l {
+                LookupResult::Output(output) => break output,
+                LookupResult::Load { load, continuation } => (load, continuation),
+            };
+
+            let mut r: Option<Arc<gimli::Dwarf<_>>> = None;
+            if let Some(dwp) = self.dwarf_package.as_ref() {
+                if let Ok(Some(cu)) = dwp.find_cu(load.dwo_id, &load.parent) {
+                    r = Some(Arc::new(cu));
+                }
+            }
+
+            if r.is_none() {
+                let mut path = PathBuf::new();
+                if let Some(p) = load.comp_dir.as_ref() {
+                    if let Ok(p) = convert_path(p) {
+                        path.push(p);
+                    }
+                }
+
+                if let Some(p) = load.path.as_ref() {
+                    if let Ok(p) = convert_path(p) {
+                        path.push(p);
+                    }
+                }
+
+                if let Ok(file) = File::open(&path) {
+                    if let Ok(map) = unsafe { memmap2::Mmap::map(&file) } {
+                        if let Ok(file) = object::File::parse(&*map) {
+                            let endian = if file.is_little_endian() {
+                                gimli::RunTimeEndian::Little
+                            } else {
+                                gimli::RunTimeEndian::Big
+                            };
+
+                            r = gimli::Dwarf::load(|id| {
+                                load_section(id, &file, endian, &mut self.loader)
+                            })
+                            .ok()
+                            .map(|mut dwo_dwarf| {
+                                dwo_dwarf.make_dwo(&load.parent);
+                                Arc::new(dwo_dwarf)
+                            });
+                        }
+                    }
+                }
+            }
+
+            l = continuation.resume(r);
+        }
+    }
+}

vendor/addr2line/src/function.rs

@@ -0,0 +1,555 @@
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use core::cmp::Ordering;
+use core::iter;
+
+use crate::lazy::LazyCell;
+use crate::maybe_small;
+use crate::{Context, DebugFile, Error, RangeAttributes};
+
+pub(crate) struct Functions<R: gimli::Reader> {
+    /// List of all `DW_TAG_subprogram` details in the unit.
+    pub(crate) functions: Box<
+        [(
+            gimli::UnitOffset<R::Offset>,
+            LazyCell<Result<Function<R>, Error>>,
+        )],
+    >,
+    /// List of `DW_TAG_subprogram` address ranges in the unit.
+    pub(crate) addresses: Box<[FunctionAddress]>,
+}
+
+/// A single address range for a function.
+///
+/// It is possible for a function to have multiple address ranges; this
+/// is handled by having multiple `FunctionAddress` entries with the same
+/// `function` field.
+pub(crate) struct FunctionAddress {
+    range: gimli::Range,
+    /// An index into `Functions::functions`.
+    pub(crate) function: usize,
+}
+
+pub(crate) struct Function<R: gimli::Reader> {
+    pub(crate) dw_die_offset: gimli::UnitOffset<R::Offset>,
+    pub(crate) name: Option<R>,
+    /// List of all `DW_TAG_inlined_subroutine` details in this function.
+    inlined_functions: Box<[InlinedFunction<R>]>,
+    /// List of `DW_TAG_inlined_subroutine` address ranges in this function.
+    inlined_addresses: Box<[InlinedFunctionAddress]>,
+}
+
+pub(crate) struct InlinedFunctionAddress {
+    range: gimli::Range,
+    call_depth: usize,
+    /// An index into `Function::inlined_functions`.
+    function: usize,
+}
+
+pub(crate) struct InlinedFunction<R: gimli::Reader> {
+    pub(crate) dw_die_offset: gimli::UnitOffset<R::Offset>,
+    pub(crate) name: Option<R>,
+    pub(crate) call_file: Option<u64>,
+    pub(crate) call_line: u32,
+    pub(crate) call_column: u32,
+}
+
+impl<R: gimli::Reader> Functions<R> {
+    pub(crate) fn parse(
+        unit: &gimli::Unit<R>,
+        sections: &gimli::Dwarf<R>,
+    ) -> Result<Functions<R>, Error> {
+        let mut functions = Vec::new();
+        let mut addresses = Vec::new();
+        let mut entries = unit.entries_raw(None)?;
+        while !entries.is_empty() {
+            let dw_die_offset = entries.next_offset();
+            if let Some(abbrev) = entries.read_abbreviation()? {
+                if abbrev.tag() == gimli::DW_TAG_subprogram {
+                    let mut ranges = RangeAttributes::default();
+                    for spec in abbrev.attributes() {
+                        match entries.read_attribute(*spec) {
+                            Ok(ref attr) => {
+                                match attr.name() {
+                                    gimli::DW_AT_low_pc => match attr.value() {
+                                        gimli::AttributeValue::Addr(val) => {
+                                            ranges.low_pc = Some(val)
+                                        }
+                                        gimli::AttributeValue::DebugAddrIndex(index) => {
+                                            ranges.low_pc = Some(sections.address(unit, index)?);
+                                        }
+                                        _ => {}
+                                    },
+                                    gimli::DW_AT_high_pc => match attr.value() {
+                                        gimli::AttributeValue::Addr(val) => {
+                                            ranges.high_pc = Some(val)
+                                        }
+                                        gimli::AttributeValue::DebugAddrIndex(index) => {
+                                            ranges.high_pc = Some(sections.address(unit, index)?);
+                                        }
+                                        gimli::AttributeValue::Udata(val) => {
+                                            ranges.size = Some(val)
+                                        }
+                                        _ => {}
+                                    },
+                                    gimli::DW_AT_ranges => {
+                                        ranges.ranges_offset =
+                                            sections.attr_ranges_offset(unit, attr.value())?;
+                                    }
+                                    _ => {}
+                                };
+                            }
+                            Err(e) => return Err(e),
+                        }
+                    }
+
+                    let function_index = functions.len();
+                    if ranges.for_each_range(sections, unit, |range| {
+                        addresses.push(FunctionAddress {
+                            range,
+                            function: function_index,
+                        });
+                    })? {
+                        functions.push((dw_die_offset, LazyCell::new()));
+                    }
+                } else {
+                    entries.skip_attributes(abbrev.attributes())?;
+                }
+            }
+        }
+
+        // The binary search requires the addresses to be sorted.
+        //
+        // It also requires them to be non-overlapping.  In practice, overlapping
+        // function ranges are unlikely, so we don't try to handle that yet.
+        //
+        // It's possible for multiple functions to have the same address range if the
+        // compiler can detect and remove functions with identical code.  In that case
+        // we'll nondeterministically return one of them.
+        addresses.sort_by_key(|x| x.range.begin);
+
+        Ok(Functions {
+            functions: functions.into_boxed_slice(),
+            addresses: addresses.into_boxed_slice(),
+        })
+    }
+
+    pub(crate) fn find_address(&self, probe: u64) -> Option<usize> {
+        self.addresses
+            .binary_search_by(|address| {
+                if probe < address.range.begin {
+                    Ordering::Greater
+                } else if probe >= address.range.end {
+                    Ordering::Less
+                } else {
+                    Ordering::Equal
+                }
+            })
+            .ok()
+    }
+
+    pub(crate) fn parse_inlined_functions(
+        &self,
+        file: DebugFile,
+        unit: &gimli::Unit<R>,
+        ctx: &Context<R>,
+        sections: &gimli::Dwarf<R>,
+    ) -> Result<(), Error> {
+        for function in &*self.functions {
+            function
+                .1
+                .borrow_with(|| Function::parse(function.0, file, unit, ctx, sections))
+                .as_ref()
+                .map_err(Error::clone)?;
+        }
+        Ok(())
+    }
+}
+
+impl<R: gimli::Reader> Function<R> {
+    pub(crate) fn parse(
+        dw_die_offset: gimli::UnitOffset<R::Offset>,
+        file: DebugFile,
+        unit: &gimli::Unit<R>,
+        ctx: &Context<R>,
+        sections: &gimli::Dwarf<R>,
+    ) -> Result<Self, Error> {
+        let mut entries = unit.entries_raw(Some(dw_die_offset))?;
+        let depth = entries.next_depth();
+        let abbrev = entries.read_abbreviation()?.unwrap();
+        debug_assert_eq!(abbrev.tag(), gimli::DW_TAG_subprogram);
+
+        let mut name = None;
+        for spec in abbrev.attributes() {
+            match entries.read_attribute(*spec) {
+                Ok(ref attr) => {
+                    match attr.name() {
+                        gimli::DW_AT_linkage_name | gimli::DW_AT_MIPS_linkage_name => {
+                            if let Ok(val) = sections.attr_string(unit, attr.value()) {
+                                name = Some(val);
+                            }
+                        }
+                        gimli::DW_AT_name => {
+                            if name.is_none() {
+                                name = sections.attr_string(unit, attr.value()).ok();
+                            }
+                        }
+                        gimli::DW_AT_abstract_origin | gimli::DW_AT_specification => {
+                            if name.is_none() {
+                                name = name_attr(attr.value(), file, unit, ctx, sections, 16)?;
+                            }
+                        }
+                        _ => {}
+                    };
+                }
+                Err(e) => return Err(e),
+            }
+        }
+
+        let mut inlined_functions = Vec::new();
+        let mut inlined_addresses = Vec::new();
+        Function::parse_children(
+            &mut entries,
+            depth,
+            file,
+            unit,
+            ctx,
+            sections,
+            &mut inlined_functions,
+            &mut inlined_addresses,
+            0,
+        )?;
+
+        // Sort ranges in "breadth-first traversal order", i.e. first by call_depth
+        // and then by range.begin. This allows finding the range containing an
+        // address at a certain depth using binary search.
+        // Note: Using DFS order, i.e. ordering by range.begin first and then by
+        // call_depth, would not work! Consider the two examples
+        // "[0..10 at depth 0], [0..2 at depth 1], [6..8 at depth 1]"  and
+        // "[0..5 at depth 0], [0..2 at depth 1], [5..10 at depth 0], [6..8 at depth 1]".
+        // In this example, if you want to look up address 7 at depth 0, and you
+        // encounter [0..2 at depth 1], are you before or after the target range?
+        // You don't know.
+        inlined_addresses.sort_by(|r1, r2| {
+            if r1.call_depth < r2.call_depth {
+                Ordering::Less
+            } else if r1.call_depth > r2.call_depth {
+                Ordering::Greater
+            } else if r1.range.begin < r2.range.begin {
+                Ordering::Less
+            } else if r1.range.begin > r2.range.begin {
+                Ordering::Greater
+            } else {
+                Ordering::Equal
+            }
+        });
+
+        Ok(Function {
+            dw_die_offset,
+            name,
+            inlined_functions: inlined_functions.into_boxed_slice(),
+            inlined_addresses: inlined_addresses.into_boxed_slice(),
+        })
+    }
+
+    fn parse_children(
+        entries: &mut gimli::EntriesRaw<'_, '_, R>,
+        depth: isize,
+        file: DebugFile,
+        unit: &gimli::Unit<R>,
+        ctx: &Context<R>,
+        sections: &gimli::Dwarf<R>,
+        inlined_functions: &mut Vec<InlinedFunction<R>>,
+        inlined_addresses: &mut Vec<InlinedFunctionAddress>,
+        inlined_depth: usize,
+    ) -> Result<(), Error> {
+        loop {
+            let dw_die_offset = entries.next_offset();
+            let next_depth = entries.next_depth();
+            if next_depth <= depth {
+                return Ok(());
+            }
+            if let Some(abbrev) = entries.read_abbreviation()? {
+                match abbrev.tag() {
+                    gimli::DW_TAG_subprogram => {
+                        Function::skip(entries, abbrev, next_depth)?;
+                    }
+                    gimli::DW_TAG_inlined_subroutine => {
+                        InlinedFunction::parse(
+                            dw_die_offset,
+                            entries,
+                            abbrev,
+                            next_depth,
+                            file,
+                            unit,
+                            ctx,
+                            sections,
+                            inlined_functions,
+                            inlined_addresses,
+                            inlined_depth,
+                        )?;
+                    }
+                    _ => {
+                        entries.skip_attributes(abbrev.attributes())?;
+                    }
+                }
+            }
+        }
+    }
+
+    fn skip(
+        entries: &mut gimli::EntriesRaw<'_, '_, R>,
+        abbrev: &gimli::Abbreviation,
+        depth: isize,
+    ) -> Result<(), Error> {
+        // TODO: use DW_AT_sibling
+        entries.skip_attributes(abbrev.attributes())?;
+        while entries.next_depth() > depth {
+            if let Some(abbrev) = entries.read_abbreviation()? {
+                entries.skip_attributes(abbrev.attributes())?;
+            }
+        }
+        Ok(())
+    }
+
+    /// Build the list of inlined functions that contain `probe`.
+    pub(crate) fn find_inlined_functions(
+        &self,
+        probe: u64,
+    ) -> iter::Rev<maybe_small::IntoIter<&InlinedFunction<R>>> {
+        // `inlined_functions` is ordered from outside to inside.
+        let mut inlined_functions = maybe_small::Vec::new();
+        let mut inlined_addresses = &self.inlined_addresses[..];
+        loop {
+            let current_depth = inlined_functions.len();
+            // Look up (probe, current_depth) in inline_ranges.
+            // `inlined_addresses` is sorted in "breadth-first traversal order", i.e.
+            // by `call_depth` first, and then by `range.begin`. See the comment at
+            // the sort call for more information about why.
+            let search = inlined_addresses.binary_search_by(|range| {
+                if range.call_depth > current_depth {
+                    Ordering::Greater
+                } else if range.call_depth < current_depth {
+                    Ordering::Less
+                } else if range.range.begin > probe {
+                    Ordering::Greater
+                } else if range.range.end <= probe {
+                    Ordering::Less
+                } else {
+                    Ordering::Equal
+                }
+            });
+            if let Ok(index) = search {
+                let function_index = inlined_addresses[index].function;
+                inlined_functions.push(&self.inlined_functions[function_index]);
+                inlined_addresses = &inlined_addresses[index + 1..];
+            } else {
+                break;
+            }
+        }
+        inlined_functions.into_iter().rev()
+    }
+}
+
+impl<R: gimli::Reader> InlinedFunction<R> {
+    fn parse(
+        dw_die_offset: gimli::UnitOffset<R::Offset>,
+        entries: &mut gimli::EntriesRaw<'_, '_, R>,
+        abbrev: &gimli::Abbreviation,
+        depth: isize,
+        file: DebugFile,
+        unit: &gimli::Unit<R>,
+        ctx: &Context<R>,
+        sections: &gimli::Dwarf<R>,
+        inlined_functions: &mut Vec<InlinedFunction<R>>,
+        inlined_addresses: &mut Vec<InlinedFunctionAddress>,
+        inlined_depth: usize,
+    ) -> Result<(), Error> {
+        let mut ranges = RangeAttributes::default();
+        let mut name = None;
+        let mut call_file = None;
+        let mut call_line = 0;
+        let mut call_column = 0;
+        for spec in abbrev.attributes() {
+            match entries.read_attribute(*spec) {
+                Ok(ref attr) => match attr.name() {
+                    gimli::DW_AT_low_pc => match attr.value() {
+                        gimli::AttributeValue::Addr(val) => ranges.low_pc = Some(val),
+                        gimli::AttributeValue::DebugAddrIndex(index) => {
+                            ranges.low_pc = Some(sections.address(unit, index)?);
+                        }
+                        _ => {}
+                    },
+                    gimli::DW_AT_high_pc => match attr.value() {
+                        gimli::AttributeValue::Addr(val) => ranges.high_pc = Some(val),
+                        gimli::AttributeValue::DebugAddrIndex(index) => {
+                            ranges.high_pc = Some(sections.address(unit, index)?);
+                        }
+                        gimli::AttributeValue::Udata(val) => ranges.size = Some(val),
+                        _ => {}
+                    },
+                    gimli::DW_AT_ranges => {
+                        ranges.ranges_offset = sections.attr_ranges_offset(unit, attr.value())?;
+                    }
+                    gimli::DW_AT_linkage_name | gimli::DW_AT_MIPS_linkage_name => {
+                        if let Ok(val) = sections.attr_string(unit, attr.value()) {
+                            name = Some(val);
+                        }
+                    }
+                    gimli::DW_AT_name => {
+                        if name.is_none() {
+                            name = sections.attr_string(unit, attr.value()).ok();
+                        }
+                    }
+                    gimli::DW_AT_abstract_origin | gimli::DW_AT_specification => {
+                        if name.is_none() {
+                            name = name_attr(attr.value(), file, unit, ctx, sections, 16)?;
+                        }
+                    }
+                    gimli::DW_AT_call_file => {
+                        // There is a spec issue [1] with how DW_AT_call_file is specified in DWARF 5.
+                        // Before, a file index of 0 would indicate no source file, however in
+                        // DWARF 5 this could be a valid index into the file table.
+                        //
+                        // Implementations such as LLVM generates a file index of 0 when DWARF 5 is
+                        // used.
+                        //
+                        // Thus, if we see a version of 5 or later, treat a file index of 0 as such.
+                        // [1]: http://wiki.dwarfstd.org/index.php?title=DWARF5_Line_Table_File_Numbers
+                        if let gimli::AttributeValue::FileIndex(fi) = attr.value() {
+                            if fi > 0 || unit.header.version() >= 5 {
+                                call_file = Some(fi);
+                            }
+                        }
+                    }
+                    gimli::DW_AT_call_line => {
+                        call_line = attr.udata_value().unwrap_or(0) as u32;
+                    }
+                    gimli::DW_AT_call_column => {
+                        call_column = attr.udata_value().unwrap_or(0) as u32;
+                    }
+                    _ => {}
+                },
+                Err(e) => return Err(e),
+            }
+        }
+
+        let function_index = inlined_functions.len();
+        inlined_functions.push(InlinedFunction {
+            dw_die_offset,
+            name,
+            call_file,
+            call_line,
+            call_column,
+        });
+
+        ranges.for_each_range(sections, unit, |range| {
+            inlined_addresses.push(InlinedFunctionAddress {
+                range,
+                call_depth: inlined_depth,
+                function: function_index,
+            });
+        })?;
+
+        Function::parse_children(
+            entries,
+            depth,
+            file,
+            unit,
+            ctx,
+            sections,
+            inlined_functions,
+            inlined_addresses,
+            inlined_depth + 1,
+        )
+    }
+}
+
+fn name_attr<R>(
+    attr: gimli::AttributeValue<R>,
+    mut file: DebugFile,
+    unit: &gimli::Unit<R>,
+    ctx: &Context<R>,
+    sections: &gimli::Dwarf<R>,
+    recursion_limit: usize,
+) -> Result<Option<R>, Error>
+where
+    R: gimli::Reader,
+{
+    if recursion_limit == 0 {
+        return Ok(None);
+    }
+
+    match attr {
+        gimli::AttributeValue::UnitRef(offset) => {
+            name_entry(file, unit, offset, ctx, sections, recursion_limit)
+        }
+        gimli::AttributeValue::DebugInfoRef(dr) => {
+            let (unit, offset) = ctx.find_unit(dr, file)?;
+            name_entry(file, unit, offset, ctx, sections, recursion_limit)
+        }
+        gimli::AttributeValue::DebugInfoRefSup(dr) => {
+            if let Some(sup_sections) = sections.sup.as_ref() {
+                file = DebugFile::Supplementary;
+                let (unit, offset) = ctx.find_unit(dr, file)?;
+                name_entry(file, unit, offset, ctx, sup_sections, recursion_limit)
+            } else {
+                Ok(None)
+            }
+        }
+        _ => Ok(None),
+    }
+}
+
+fn name_entry<R>(
+    file: DebugFile,
+    unit: &gimli::Unit<R>,
+    offset: gimli::UnitOffset<R::Offset>,
+    ctx: &Context<R>,
+    sections: &gimli::Dwarf<R>,
+    recursion_limit: usize,
+) -> Result<Option<R>, Error>
+where
+    R: gimli::Reader,
+{
+    let mut entries = unit.entries_raw(Some(offset))?;
+    let abbrev = if let Some(abbrev) = entries.read_abbreviation()? {
+        abbrev
+    } else {
+        return Err(gimli::Error::NoEntryAtGivenOffset);
+    };
+
+    let mut name = None;
+    let mut next = None;
+    for spec in abbrev.attributes() {
+        match entries.read_attribute(*spec) {
+            Ok(ref attr) => match attr.name() {
+                gimli::DW_AT_linkage_name | gimli::DW_AT_MIPS_linkage_name => {
+                    if let Ok(val) = sections.attr_string(unit, attr.value()) {
+                        return Ok(Some(val));
+                    }
+                }
+                gimli::DW_AT_name => {
+                    if let Ok(val) = sections.attr_string(unit, attr.value()) {
+                        name = Some(val);
+                    }
+                }
+                gimli::DW_AT_abstract_origin | gimli::DW_AT_specification => {
+                    next = Some(attr.value());
+                }
+                _ => {}
+            },
+            Err(e) => return Err(e),
+        }
+    }
+
+    if name.is_some() {
+        return Ok(name);
+    }
+
+    if let Some(next) = next {
+        return name_attr(next, file, unit, ctx, sections, recursion_limit - 1);
+    }
+
+    Ok(None)
+}

vendor/addr2line/src/lazy.rs

@@ -0,0 +1,31 @@
+use core::cell::UnsafeCell;
+
+pub struct LazyCell<T> {
+    contents: UnsafeCell<Option<T>>,
+}
+impl<T> LazyCell<T> {
+    pub fn new() -> LazyCell<T> {
+        LazyCell {
+            contents: UnsafeCell::new(None),
+        }
+    }
+
+    pub fn borrow(&self) -> Option<&T> {
+        unsafe { &*self.contents.get() }.as_ref()
+    }
+
+    pub fn borrow_with(&self, closure: impl FnOnce() -> T) -> &T {
+        // First check if we're already initialized...
+        let ptr = self.contents.get();
+        if let Some(val) = unsafe { &*ptr } {
+            return val;
+        }
+        // Note that while we're executing `closure` our `borrow_with` may
+        // be called recursively. This means we need to check again after
+        // the closure has executed. For that we use the `get_or_insert`
+        // method which will only perform mutation if we aren't already
+        // `Some`.
+        let val = closure();
+        unsafe { (*ptr).get_or_insert(val) }
+    }
+}