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//! Line info generation (`.debug_line`)
use std::ffi::OsStr;
use std::path::{Component, Path};
use crate::debuginfo::FunctionDebugContext;
use crate::prelude::*;
use rustc_data_structures::sync::Lrc;
use rustc_span::{
FileName, Pos, SourceFile, SourceFileAndLine, SourceFileHash, SourceFileHashAlgorithm,
};
use cranelift_codegen::binemit::CodeOffset;
use cranelift_codegen::MachSrcLoc;
use gimli::write::{
Address, AttributeValue, FileId, FileInfo, LineProgram, LineString, LineStringTable,
};
// OPTIMIZATION: It is cheaper to do this in one pass than using `.parent()` and `.file_name()`.
fn split_path_dir_and_file(path: &Path) -> (&Path, &OsStr) {
let mut iter = path.components();
let file_name = match iter.next_back() {
Some(Component::Normal(p)) => p,
component => {
panic!(
"Path component {:?} of path {} is an invalid filename",
component,
path.display()
);
}
};
let parent = iter.as_path();
(parent, file_name)
}
// OPTIMIZATION: Avoid UTF-8 validation on UNIX.
fn osstr_as_utf8_bytes(path: &OsStr) -> &[u8] {
#[cfg(unix)]
{
use std::os::unix::ffi::OsStrExt;
path.as_bytes()
}
#[cfg(not(unix))]
{
path.to_str().unwrap().as_bytes()
}
}
const MD5_LEN: usize = 16;
fn make_file_info(hash: SourceFileHash) -> Option<FileInfo> {
if hash.kind == SourceFileHashAlgorithm::Md5 {
let mut buf = [0u8; MD5_LEN];
buf.copy_from_slice(hash.hash_bytes());
Some(FileInfo { timestamp: 0, size: 0, md5: buf })
} else {
None
}
}
impl DebugContext {
pub(crate) fn get_span_loc(
tcx: TyCtxt<'_>,
function_span: Span,
span: Span,
) -> (Lrc<SourceFile>, u64, u64) {
// Based on https://github.com/rust-lang/rust/blob/e369d87b015a84653343032833d65d0545fd3f26/src/librustc_codegen_ssa/mir/mod.rs#L116-L131
// In order to have a good line stepping behavior in debugger, we overwrite debug
// locations of macro expansions with that of the outermost expansion site (when the macro is
// annotated with `#[collapse_debuginfo]` or when `-Zdebug-macros` is provided).
let span = if tcx.should_collapse_debuginfo(span) {
span
} else {
// Walk up the macro expansion chain until we reach a non-expanded span.
// We also stop at the function body level because no line stepping can occur
// at the level above that.
rustc_span::hygiene::walk_chain(span, function_span.ctxt())
};
match tcx.sess.source_map().lookup_line(span.lo()) {
Ok(SourceFileAndLine { sf: file, line }) => {
let line_pos = file.line_begin_pos(span.lo());
(
file,
u64::try_from(line).unwrap() + 1,
u64::from((span.lo() - line_pos).to_u32()) + 1,
)
}
Err(file) => (file, 0, 0),
}
}
pub(crate) fn add_source_file(&mut self, source_file: &SourceFile) -> FileId {
let line_program: &mut LineProgram = &mut self.dwarf.unit.line_program;
let line_strings: &mut LineStringTable = &mut self.dwarf.line_strings;
match &source_file.name {
FileName::Real(path) => {
let (dir_path, file_name) =
split_path_dir_and_file(path.remapped_path_if_available());
let dir_name = osstr_as_utf8_bytes(dir_path.as_os_str());
let file_name = osstr_as_utf8_bytes(file_name);
let dir_id = if !dir_name.is_empty() {
let dir_name = LineString::new(dir_name, line_program.encoding(), line_strings);
line_program.add_directory(dir_name)
} else {
line_program.default_directory()
};
let file_name = LineString::new(file_name, line_program.encoding(), line_strings);
let info = make_file_info(source_file.src_hash);
line_program.file_has_md5 &= info.is_some();
line_program.add_file(file_name, dir_id, info)
}
// FIXME give more appropriate file names
filename => {
let dir_id = line_program.default_directory();
let dummy_file_name = LineString::new(
filename.prefer_remapped().to_string().into_bytes(),
line_program.encoding(),
line_strings,
);
line_program.add_file(dummy_file_name, dir_id, None)
}
}
}
}
impl FunctionDebugContext {
pub(crate) fn add_dbg_loc(&mut self, file_id: FileId, line: u64, column: u64) -> SourceLoc {
let (index, _) = self.source_loc_set.insert_full((file_id, line, column));
SourceLoc::new(u32::try_from(index).unwrap())
}
pub(super) fn create_debug_lines(
&mut self,
debug_context: &mut DebugContext,
symbol: usize,
context: &Context,
) -> CodeOffset {
let create_row_for_span =
|debug_context: &mut DebugContext, source_loc: (FileId, u64, u64)| {
let (file_id, line, col) = source_loc;
debug_context.dwarf.unit.line_program.row().file = file_id;
debug_context.dwarf.unit.line_program.row().line = line;
debug_context.dwarf.unit.line_program.row().column = col;
debug_context.dwarf.unit.line_program.generate_row();
};
debug_context
.dwarf
.unit
.line_program
.begin_sequence(Some(Address::Symbol { symbol, addend: 0 }));
let mut func_end = 0;
let mcr = context.compiled_code().unwrap();
for &MachSrcLoc { start, end, loc } in mcr.buffer.get_srclocs_sorted() {
debug_context.dwarf.unit.line_program.row().address_offset = u64::from(start);
if !loc.is_default() {
let source_loc = *self.source_loc_set.get_index(loc.bits() as usize).unwrap();
create_row_for_span(debug_context, source_loc);
} else {
create_row_for_span(debug_context, self.function_source_loc);
}
func_end = end;
}
debug_context.dwarf.unit.line_program.end_sequence(u64::from(func_end));
let func_end = mcr.buffer.total_size();
assert_ne!(func_end, 0);
let entry = debug_context.dwarf.unit.get_mut(self.entry_id);
entry.set(
gimli::DW_AT_low_pc,
AttributeValue::Address(Address::Symbol { symbol, addend: 0 }),
);
entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(func_end)));
func_end
}
}
|
