src/debuginfo/mod.rs

   1 mod emit;
   2 mod line_info;
   3 mod unwind;
   4
   5 use crate::prelude::*;
   6
   7 use cranelift_codegen::entity::EntityRef;
   8 use cranelift_codegen::ir::{StackSlots, ValueLabel, ValueLoc};
   9 use cranelift_codegen::isa::TargetIsa;
  10 use cranelift_codegen::ValueLocRange;
  11
  12 use gimli::write::{
  13     Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
  14     LocationList, Range, RangeList, UnitEntryId,
  15 };
  16 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
  17
  18 pub(crate) use emit::{DebugReloc, DebugRelocName};
  19 pub(crate) use unwind::UnwindContext;
  20
  21 fn target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian {
  22     use rustc_target::abi::Endian;
  23
  24     match tcx.data_layout.endian {
  25         Endian::Big => RunTimeEndian::Big,
  26         Endian::Little => RunTimeEndian::Little,
  27     }
  28 }
  29
  30 pub(crate) struct DebugContext<'tcx> {
  31     tcx: TyCtxt<'tcx>,
  32
  33     endian: RunTimeEndian,
  34
  35     dwarf: DwarfUnit,
  36     unit_range_list: RangeList,
  37
  38     clif_types: FxHashMap<Type, UnitEntryId>,
  39     types: FxHashMap<Ty<'tcx>, UnitEntryId>,
  40 }
  41
  42 impl<'tcx> DebugContext<'tcx> {
  43     pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
  44         let encoding = Encoding {
  45             format: Format::Dwarf32,
  46             // TODO: this should be configurable
  47             // macOS doesn't seem to support DWARF > 3
  48             // 5 version is required for md5 file hash
  49             version: if tcx.sess.target.target.options.is_like_osx {
  50                 3
  51             } else {
  52                 // FIXME change to version 5 once the gdb and lldb shipping with the latest debian
  53                 // support it.
  54                 4
  55             },
  56             address_size: isa.frontend_config().pointer_bytes(),
  57         };
  58
  59         let mut dwarf = DwarfUnit::new(encoding);
  60
  61         // FIXME: how to get version when building out of tree?
  62         // Normally this would use option_env!("CFG_VERSION").
  63         let producer = format!("cg_clif (rustc {})", "unknown version");
  64         let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
  65         let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
  66             Some(path) => {
  67                 let name = path.to_string_lossy().into_owned();
  68                 (name, None)
  69             }
  70             None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
  71         };
  72
  73         let mut line_program = LineProgram::new(
  74             encoding,
  75             LineEncoding::default(),
  76             LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
  77             LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
  78             file_info,
  79         );
  80         line_program.file_has_md5 = file_info.is_some();
  81
  82         dwarf.unit.line_program = line_program;
  83
  84         {
  85             let name = dwarf.strings.add(name);
  86             let comp_dir = dwarf.strings.add(comp_dir);
  87
  88             let root = dwarf.unit.root();
  89             let root = dwarf.unit.get_mut(root);
  90             root.set(
  91                 gimli::DW_AT_producer,
  92                 AttributeValue::StringRef(dwarf.strings.add(producer)),
  93             );
  94             root.set(
  95                 gimli::DW_AT_language,
  96                 AttributeValue::Language(gimli::DW_LANG_Rust),
  97             );
  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(
 101                 gimli::DW_AT_low_pc,
 102                 AttributeValue::Address(Address::Constant(0)),
 103             );
 104         }
 105
 106         DebugContext {
 107             tcx,
 108
 109             endian: target_endian(tcx),
 110
 111             dwarf,
 112             unit_range_list: RangeList(Vec::new()),
 113
 114             clif_types: FxHashMap::default(),
 115             types: FxHashMap::default(),
 116         }
 117     }
 118
 119     fn dwarf_ty_for_clif_ty(&mut self, ty: Type) -> UnitEntryId {
 120         if let Some(type_id) = self.clif_types.get(&ty) {
 121             return *type_id;
 122         }
 123
 124         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 125
 126         let primitive = |dwarf: &mut DwarfUnit, ate| {
 127             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 128             let type_entry = dwarf.unit.get_mut(type_id);
 129             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 130             type_id
 131         };
 132
 133         let type_id = if ty.is_bool() {
 134             primitive(&mut self.dwarf, gimli::DW_ATE_boolean)
 135         } else if ty.is_int() {
 136             primitive(&mut self.dwarf, gimli::DW_ATE_address)
 137         } else if ty.is_float() {
 138             primitive(&mut self.dwarf, gimli::DW_ATE_float)
 139         } else {
 140             new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type)
 141         };
 142
 143         let type_entry = self.dwarf.unit.get_mut(type_id);
 144         type_entry.set(
 145             gimli::DW_AT_name,
 146             AttributeValue::String(format!("{}", ty).replace('i', "u").into_bytes()),
 147         );
 148         type_entry.set(
 149             gimli::DW_AT_byte_size,
 150             AttributeValue::Udata(u64::from(ty.bytes())),
 151         );
 152
 153         type_id
 154     }
 155
 156     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 157         if let Some(type_id) = self.types.get(ty) {
 158             return *type_id;
 159         }
 160
 161         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 162
 163         let primitive = |dwarf: &mut DwarfUnit, ate| {
 164             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 165             let type_entry = dwarf.unit.get_mut(type_id);
 166             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 167             type_id
 168         };
 169
 170         let name = format!("{}", ty);
 171         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 172
 173         let type_id = match ty.kind {
 174             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 175             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 176             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 177             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 178             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 179             ty::Ref(_, pointee_ty, _mutbl)
 180             | ty::RawPtr(ty::TypeAndMut {
 181                 ty: pointee_ty,
 182                 mutbl: _mutbl,
 183             }) => {
 184                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 185
 186                 // Ensure that type is inserted before recursing to avoid duplicates
 187                 self.types.insert(ty, type_id);
 188
 189                 let pointee = self.dwarf_ty(pointee_ty);
 190
 191                 let type_entry = self.dwarf.unit.get_mut(type_id);
 192
 193                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 194                 type_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(pointee));
 195
 196                 type_id
 197             }
 198             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 199                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 200
 201                 // Ensure that type is inserted before recursing to avoid duplicates
 202                 self.types.insert(ty, type_id);
 203
 204                 let variant = adt_def.non_enum_variant();
 205
 206                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 207                     let field_offset = layout.fields.offset(field_idx);
 208                     let field_layout = layout
 209                         .field(
 210                             &layout::LayoutCx {
 211                                 tcx: self.tcx,
 212                                 param_env: ParamEnv::reveal_all(),
 213                             },
 214                             field_idx,
 215                         )
 216                         .unwrap();
 217
 218                     let field_type = self.dwarf_ty(field_layout.ty);
 219
 220                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 221                     let field_entry = self.dwarf.unit.get_mut(field_id);
 222
 223                     field_entry.set(
 224                         gimli::DW_AT_name,
 225                         AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()),
 226                     );
 227                     field_entry.set(
 228                         gimli::DW_AT_data_member_location,
 229                         AttributeValue::Udata(field_offset.bytes()),
 230                     );
 231                     field_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(field_type));
 232                 }
 233
 234                 type_id
 235             }
 236             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 237         };
 238
 239         let type_entry = self.dwarf.unit.get_mut(type_id);
 240
 241         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 242         type_entry.set(
 243             gimli::DW_AT_byte_size,
 244             AttributeValue::Udata(layout.size.bytes()),
 245         );
 246
 247         self.types.insert(ty, type_id);
 248
 249         type_id
 250     }
 251
 252     fn define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 253         let dw_ty = self.dwarf_ty(ty);
 254
 255         let var_id = self.dwarf.unit.add(scope, gimli::DW_TAG_variable);
 256         let var_entry = self.dwarf.unit.get_mut(var_id);
 257
 258         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 259         var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
 260
 261         var_id
 262     }
 263
 264     pub(crate) fn define_function(
 265         &mut self,
 266         instance: Instance<'tcx>,
 267         func_id: FuncId,
 268         name: &str,
 269         isa: &dyn TargetIsa,
 270         context: &Context,
 271         source_info_set: &indexmap::IndexSet<SourceInfo>,
 272         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 273     ) {
 274         let symbol = func_id.as_u32() as usize;
 275         let mir = self.tcx.instance_mir(instance.def);
 276
 277         // FIXME: add to appropriate scope instead of root
 278         let scope = self.dwarf.unit.root();
 279
 280         let entry_id = self.dwarf.unit.add(scope, gimli::DW_TAG_subprogram);
 281         let entry = self.dwarf.unit.get_mut(entry_id);
 282         let name_id = self.dwarf.strings.add(name);
 283         // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
 284         entry.set(gimli::DW_AT_name, AttributeValue::StringRef(name_id));
 285         entry.set(
 286             gimli::DW_AT_linkage_name,
 287             AttributeValue::StringRef(name_id),
 288         );
 289
 290         let end =
 291             self.create_debug_lines(isa, symbol, entry_id, context, mir.span, source_info_set);
 292
 293         self.unit_range_list.0.push(Range::StartLength {
 294             begin: Address::Symbol { symbol, addend: 0 },
 295             length: u64::from(end),
 296         });
 297
 298         if isa.get_mach_backend().is_some() {
 299             return; // Not yet implemented for the AArch64 backend.
 300         }
 301
 302         let func_entry = self.dwarf.unit.get_mut(entry_id);
 303         // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
 304         func_entry.set(
 305             gimli::DW_AT_low_pc,
 306             AttributeValue::Address(Address::Symbol { symbol, addend: 0 }),
 307         );
 308         // Using Udata for DW_AT_high_pc requires at least DWARF4
 309         func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
 310
 311         // FIXME Remove once actual debuginfo for locals works.
 312         for (i, (param, &val)) in context
 313             .func
 314             .signature
 315             .params
 316             .iter()
 317             .zip(
 318                 context
 319                     .func
 320                     .dfg
 321                     .block_params(context.func.layout.entry_block().unwrap()),
 322             )
 323             .enumerate()
 324         {
 325             use cranelift_codegen::ir::ArgumentPurpose;
 326             let base_name = match param.purpose {
 327                 ArgumentPurpose::Normal => "arg",
 328                 ArgumentPurpose::StructArgument(_) => "struct_arg",
 329                 ArgumentPurpose::StructReturn => "sret",
 330                 ArgumentPurpose::Link
 331                 | ArgumentPurpose::FramePointer
 332                 | ArgumentPurpose::CalleeSaved => continue,
 333                 ArgumentPurpose::VMContext
 334                 | ArgumentPurpose::SignatureId
 335                 | ArgumentPurpose::StackLimit => unreachable!(),
 336             };
 337             let name = format!("{}{}", base_name, i);
 338
 339             let dw_ty = self.dwarf_ty_for_clif_ty(param.value_type);
 340             let loc =
 341                 translate_loc(isa, context.func.locations[val], &context.func.stack_slots).unwrap();
 342
 343             let arg_id = self
 344                 .dwarf
 345                 .unit
 346                 .add(entry_id, gimli::DW_TAG_formal_parameter);
 347             let var_entry = self.dwarf.unit.get_mut(arg_id);
 348
 349             var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 350             var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
 351             var_entry.set(gimli::DW_AT_location, AttributeValue::Exprloc(loc));
 352         }
 353
 354         // FIXME make it more reliable and implement scopes before re-enabling this.
 355         if false {
 356             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 357
 358             for (local, _local_decl) in mir.local_decls.iter_enumerated() {
 359                 let ty = self.tcx.subst_and_normalize_erasing_regions(
 360                     instance.substs,
 361                     ty::ParamEnv::reveal_all(),
 362                     &mir.local_decls[local].ty,
 363                 );
 364                 let var_id = self.define_local(entry_id, format!("{:?}", local), ty);
 365
 366                 let location = place_location(
 367                     self,
 368                     isa,
 369                     symbol,
 370                     context,
 371                     &local_map,
 372                     &value_labels_ranges,
 373                     Place {
 374                         local,
 375                         projection: ty::List::empty(),
 376                     },
 377                 );
 378
 379                 let var_entry = self.dwarf.unit.get_mut(var_id);
 380                 var_entry.set(gimli::DW_AT_location, location);
 381             }
 382         }
 383
 384         // FIXME create locals for all entries in mir.var_debug_info
 385     }
 386 }
 387
 388 fn place_location<'tcx>(
 389     debug_context: &mut DebugContext<'tcx>,
 390     isa: &dyn TargetIsa,
 391     symbol: usize,
 392     context: &Context,
 393     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 394     #[allow(rustc::default_hash_types)] value_labels_ranges: &std::collections::HashMap<
 395         ValueLabel,
 396         Vec<ValueLocRange>,
 397     >,
 398     place: Place<'tcx>,
 399 ) -> AttributeValue {
 400     assert!(place.projection.is_empty()); // FIXME implement them
 401
 402     match local_map[&place.local].inner() {
 403         CPlaceInner::Var(_local, var) => {
 404             let value_label = cranelift_codegen::ir::ValueLabel::new(var.index());
 405             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 406                 let loc_list = LocationList(
 407                     value_loc_ranges
 408                         .iter()
 409                         .map(|value_loc_range| Location::StartEnd {
 410                             begin: Address::Symbol {
 411                                 symbol,
 412                                 addend: i64::from(value_loc_range.start),
 413                             },
 414                             end: Address::Symbol {
 415                                 symbol,
 416                                 addend: i64::from(value_loc_range.end),
 417                             },
 418                             data: translate_loc(
 419                                 isa,
 420                                 value_loc_range.loc,
 421                                 &context.func.stack_slots,
 422                             )
 423                             .unwrap(),
 424                         })
 425                         .collect(),
 426                 );
 427                 let loc_list_id = debug_context.dwarf.unit.locations.add(loc_list);
 428
 429                 AttributeValue::LocationListRef(loc_list_id)
 430             } else {
 431                 // FIXME set value labels for unused locals
 432
 433                 AttributeValue::Exprloc(Expression::new())
 434             }
 435         }
 436         CPlaceInner::VarPair(_, _, _) => {
 437             // FIXME implement this
 438
 439             AttributeValue::Exprloc(Expression::new())
 440         }
 441         CPlaceInner::VarLane(_, _, _) => {
 442             // FIXME implement this
 443
 444             AttributeValue::Exprloc(Expression::new())
 445         }
 446         CPlaceInner::Addr(_, _) => {
 447             // FIXME implement this (used by arguments and returns)
 448
 449             AttributeValue::Exprloc(Expression::new())
 450
 451             // For PointerBase::Stack:
 452             //AttributeValue::Exprloc(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap())
 453         }
 454     }
 455 }
 456
 457 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 458 fn translate_loc(
 459     isa: &dyn TargetIsa,
 460     loc: ValueLoc,
 461     stack_slots: &StackSlots,
 462 ) -> Option<Expression> {
 463     match loc {
 464         ValueLoc::Reg(reg) => {
 465             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 466             let mut expr = Expression::new();
 467             expr.op_reg(gimli::Register(machine_reg));
 468             Some(expr)
 469         }
 470         ValueLoc::Stack(ss) => {
 471             if let Some(ss_offset) = stack_slots[ss].offset {
 472                 let mut expr = Expression::new();
 473                 expr.op_breg(X86_64::RBP, i64::from(ss_offset) + 16);
 474                 Some(expr)
 475             } else {
 476                 None
 477             }
 478         }
 479         _ => None,
 480     }
 481 }