1 //! Handling of everything related to debuginfo.
2
3 mod emit;
4 mod line_info;
5 mod object;
6 mod unwind;
7
8 use crate::prelude::*;
9
10 use rustc_index::vec::IndexVec;
11
12 use cranelift_codegen::entity::EntityRef;
13 use cranelift_codegen::ir::{LabelValueLoc, StackSlots, ValueLabel, ValueLoc};
14 use cranelift_codegen::isa::TargetIsa;
15 use cranelift_codegen::ValueLocRange;
16
17 use gimli::write::{
18 Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
19 LocationList, Range, RangeList, UnitEntryId,
20 };
21 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
22
23 pub(crate) use emit::{DebugReloc, DebugRelocName};
24 pub(crate) use unwind::UnwindContext;
25
target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian26 fn target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian {
27 use rustc_target::abi::Endian;
28
29 match tcx.data_layout.endian {
30 Endian::Big => RunTimeEndian::Big,
31 Endian::Little => RunTimeEndian::Little,
32 }
33 }
34
35 pub(crate) struct DebugContext<'tcx> {
36 tcx: TyCtxt<'tcx>,
37
38 endian: RunTimeEndian,
39
40 dwarf: DwarfUnit,
41 unit_range_list: RangeList,
42
43 types: FxHashMap<Ty<'tcx>, UnitEntryId>,
44 }
45
46 impl<'tcx> DebugContext<'tcx> {
new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self47 pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
48 let encoding = Encoding {
49 format: Format::Dwarf32,
50 // FIXME this should be configurable
51 // macOS doesn't seem to support DWARF > 3
52 // 5 version is required for md5 file hash
53 version: if tcx.sess.target.is_like_osx {
54 3
55 } else {
56 // FIXME change to version 5 once the gdb and lldb shipping with the latest debian
57 // support it.
58 4
59 },
60 address_size: isa.frontend_config().pointer_bytes(),
61 };
62
63 let mut dwarf = DwarfUnit::new(encoding);
64
65 let producer = format!(
66 "cg_clif (rustc {}, cranelift {})",
67 rustc_interface::util::version_str().unwrap_or("unknown version"),
68 cranelift_codegen::VERSION,
69 );
70 let comp_dir = tcx.sess.opts.working_dir.to_string_lossy(FileNameDisplayPreference::Remapped).into_owned();
71 let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
72 Some(path) => {
73 let name = path.to_string_lossy().into_owned();
74 (name, None)
75 }
76 None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
77 };
78
79 let mut line_program = LineProgram::new(
80 encoding,
81 LineEncoding::default(),
82 LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
83 LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
84 file_info,
85 );
86 line_program.file_has_md5 = file_info.is_some();
87
88 dwarf.unit.line_program = line_program;
89
90 {
91 let name = dwarf.strings.add(name);
92 let comp_dir = dwarf.strings.add(comp_dir);
93
94 let root = dwarf.unit.root();
95 let root = dwarf.unit.get_mut(root);
96 root.set(gimli::DW_AT_producer, AttributeValue::StringRef(dwarf.strings.add(producer)));
97 root.set(gimli::DW_AT_language, AttributeValue::Language(gimli::DW_LANG_Rust));
98 root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
99 root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
100 root.set(gimli::DW_AT_low_pc, AttributeValue::Address(Address::Constant(0)));
101 }
102
103 DebugContext {
104 tcx,
105
106 endian: target_endian(tcx),
107
108 dwarf,
109 unit_range_list: RangeList(Vec::new()),
110
111 types: FxHashMap::default(),
112 }
113 }
114
dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId115 fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
116 if let Some(type_id) = self.types.get(ty) {
117 return *type_id;
118 }
119
120 let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
121
122 let primitive = |dwarf: &mut DwarfUnit, ate| {
123 let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
124 let type_entry = dwarf.unit.get_mut(type_id);
125 type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
126 type_id
127 };
128
129 let name = format!("{}", ty);
130 let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
131
132 let type_id = match ty.kind() {
133 ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
134 ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
135 ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
136 ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
137 ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
138 ty::Ref(_, pointee_ty, _mutbl)
139 | ty::RawPtr(ty::TypeAndMut { ty: pointee_ty, mutbl: _mutbl }) => {
140 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
141
142 // Ensure that type is inserted before recursing to avoid duplicates
143 self.types.insert(ty, type_id);
144
145 let pointee = self.dwarf_ty(pointee_ty);
146
147 let type_entry = self.dwarf.unit.get_mut(type_id);
148
149 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
150 type_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(pointee));
151
152 type_id
153 }
154 ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
155 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
156
157 // Ensure that type is inserted before recursing to avoid duplicates
158 self.types.insert(ty, type_id);
159
160 let variant = adt_def.non_enum_variant();
161
162 for (field_idx, field_def) in variant.fields.iter().enumerate() {
163 let field_offset = layout.fields.offset(field_idx);
164 let field_layout = layout.field(
165 &layout::LayoutCx { tcx: self.tcx, param_env: ParamEnv::reveal_all() },
166 field_idx,
167 );
168
169 let field_type = self.dwarf_ty(field_layout.ty);
170
171 let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
172 let field_entry = self.dwarf.unit.get_mut(field_id);
173
174 field_entry.set(
175 gimli::DW_AT_name,
176 AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()),
177 );
178 field_entry.set(
179 gimli::DW_AT_data_member_location,
180 AttributeValue::Udata(field_offset.bytes()),
181 );
182 field_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(field_type));
183 }
184
185 type_id
186 }
187 _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
188 };
189
190 let type_entry = self.dwarf.unit.get_mut(type_id);
191
192 type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
193 type_entry.set(gimli::DW_AT_byte_size, AttributeValue::Udata(layout.size.bytes()));
194
195 self.types.insert(ty, type_id);
196
197 type_id
198 }
199
define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId200 fn define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId {
201 let dw_ty = self.dwarf_ty(ty);
202
203 let var_id = self.dwarf.unit.add(scope, gimli::DW_TAG_variable);
204 let var_entry = self.dwarf.unit.get_mut(var_id);
205
206 var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
207 var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
208
209 var_id
210 }
211
define_function( &mut self, instance: Instance<'tcx>, func_id: FuncId, name: &str, isa: &dyn TargetIsa, context: &Context, source_info_set: &indexmap::IndexSet<SourceInfo>, local_map: IndexVec<mir::Local, CPlace<'tcx>>, )212 pub(crate) fn define_function(
213 &mut self,
214 instance: Instance<'tcx>,
215 func_id: FuncId,
216 name: &str,
217 isa: &dyn TargetIsa,
218 context: &Context,
219 source_info_set: &indexmap::IndexSet<SourceInfo>,
220 local_map: IndexVec<mir::Local, CPlace<'tcx>>,
221 ) {
222 let symbol = func_id.as_u32() as usize;
223 let mir = self.tcx.instance_mir(instance.def);
224
225 // FIXME: add to appropriate scope instead of root
226 let scope = self.dwarf.unit.root();
227
228 let entry_id = self.dwarf.unit.add(scope, gimli::DW_TAG_subprogram);
229 let entry = self.dwarf.unit.get_mut(entry_id);
230 let name_id = self.dwarf.strings.add(name);
231 // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
232 entry.set(gimli::DW_AT_name, AttributeValue::StringRef(name_id));
233 entry.set(gimli::DW_AT_linkage_name, AttributeValue::StringRef(name_id));
234
235 let end = self.create_debug_lines(symbol, entry_id, context, mir.span, source_info_set);
236
237 self.unit_range_list.0.push(Range::StartLength {
238 begin: Address::Symbol { symbol, addend: 0 },
239 length: u64::from(end),
240 });
241
242 let func_entry = self.dwarf.unit.get_mut(entry_id);
243 // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
244 func_entry.set(
245 gimli::DW_AT_low_pc,
246 AttributeValue::Address(Address::Symbol { symbol, addend: 0 }),
247 );
248 // Using Udata for DW_AT_high_pc requires at least DWARF4
249 func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
250
251 // FIXME make it more reliable and implement scopes before re-enabling this.
252 if false {
253 let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
254
255 for (local, _local_decl) in mir.local_decls.iter_enumerated() {
256 let ty = self.tcx.subst_and_normalize_erasing_regions(
257 instance.substs,
258 ty::ParamEnv::reveal_all(),
259 mir.local_decls[local].ty,
260 );
261 let var_id = self.define_local(entry_id, format!("{:?}", local), ty);
262
263 let location = place_location(
264 self,
265 isa,
266 symbol,
267 context,
268 &local_map,
269 &value_labels_ranges,
270 Place { local, projection: ty::List::empty() },
271 );
272
273 let var_entry = self.dwarf.unit.get_mut(var_id);
274 var_entry.set(gimli::DW_AT_location, location);
275 }
276 }
277
278 // FIXME create locals for all entries in mir.var_debug_info
279 }
280 }
281
place_location<'tcx>( debug_context: &mut DebugContext<'tcx>, isa: &dyn TargetIsa, symbol: usize, context: &Context, local_map: &IndexVec<mir::Local, CPlace<'tcx>>, #[allow(rustc::default_hash_types)] value_labels_ranges: &std::collections::HashMap< ValueLabel, Vec<ValueLocRange>, >, place: Place<'tcx>, ) -> AttributeValue282 fn place_location<'tcx>(
283 debug_context: &mut DebugContext<'tcx>,
284 isa: &dyn TargetIsa,
285 symbol: usize,
286 context: &Context,
287 local_map: &IndexVec<mir::Local, CPlace<'tcx>>,
288 #[allow(rustc::default_hash_types)] value_labels_ranges: &std::collections::HashMap<
289 ValueLabel,
290 Vec<ValueLocRange>,
291 >,
292 place: Place<'tcx>,
293 ) -> AttributeValue {
294 assert!(place.projection.is_empty()); // FIXME implement them
295
296 match local_map[place.local].inner() {
297 CPlaceInner::Var(_local, var) => {
298 let value_label = cranelift_codegen::ir::ValueLabel::new(var.index());
299 if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
300 let loc_list = LocationList(
301 value_loc_ranges
302 .iter()
303 .map(|value_loc_range| Location::StartEnd {
304 begin: Address::Symbol {
305 symbol,
306 addend: i64::from(value_loc_range.start),
307 },
308 end: Address::Symbol { symbol, addend: i64::from(value_loc_range.end) },
309 data: translate_loc(
310 isa,
311 value_loc_range.loc,
312 &context.func.stack_slots,
313 )
314 .unwrap(),
315 })
316 .collect(),
317 );
318 let loc_list_id = debug_context.dwarf.unit.locations.add(loc_list);
319
320 AttributeValue::LocationListRef(loc_list_id)
321 } else {
322 // FIXME set value labels for unused locals
323
324 AttributeValue::Exprloc(Expression::new())
325 }
326 }
327 CPlaceInner::VarPair(_, _, _) => {
328 // FIXME implement this
329
330 AttributeValue::Exprloc(Expression::new())
331 }
332 CPlaceInner::VarLane(_, _, _) => {
333 // FIXME implement this
334
335 AttributeValue::Exprloc(Expression::new())
336 }
337 CPlaceInner::Addr(_, _) => {
338 // FIXME implement this (used by arguments and returns)
339
340 AttributeValue::Exprloc(Expression::new())
341
342 // For PointerBase::Stack:
343 //AttributeValue::Exprloc(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap())
344 }
345 }
346 }
347
348 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
translate_loc( isa: &dyn TargetIsa, loc: LabelValueLoc, stack_slots: &StackSlots, ) -> Option<Expression>349 fn translate_loc(
350 isa: &dyn TargetIsa,
351 loc: LabelValueLoc,
352 stack_slots: &StackSlots,
353 ) -> Option<Expression> {
354 match loc {
355 LabelValueLoc::ValueLoc(ValueLoc::Reg(reg)) => {
356 let machine_reg = isa.map_dwarf_register(reg).unwrap();
357 let mut expr = Expression::new();
358 expr.op_reg(gimli::Register(machine_reg));
359 Some(expr)
360 }
361 LabelValueLoc::ValueLoc(ValueLoc::Stack(ss)) => {
362 if let Some(ss_offset) = stack_slots[ss].offset {
363 let mut expr = Expression::new();
364 expr.op_breg(X86_64::RBP, i64::from(ss_offset) + 16);
365 Some(expr)
366 } else {
367 None
368 }
369 }
370 LabelValueLoc::ValueLoc(ValueLoc::Unassigned) => unreachable!(),
371 LabelValueLoc::Reg(reg) => {
372 let machine_reg = isa.map_regalloc_reg_to_dwarf(reg).unwrap();
373 let mut expr = Expression::new();
374 expr.op_reg(gimli::Register(machine_reg));
375 Some(expr)
376 }
377 LabelValueLoc::SPOffset(offset) => {
378 let mut expr = Expression::new();
379 expr.op_breg(X86_64::RSP, offset);
380 Some(expr)
381 }
382 }
383 }
384