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)
}