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,
  14     LineString, Location, 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(gimli::DW_AT_name, AttributeValue::String(format!("{}", ty).replace('i', "u").into_bytes()));
 145         type_entry.set(
 146             gimli::DW_AT_byte_size,
 147             AttributeValue::Udata(u64::from(ty.bytes())),
 148         );
 149
 150         type_id
 151     }
 152
 153     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 154         if let Some(type_id) = self.types.get(ty) {
 155             return *type_id;
 156         }
 157
 158         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 159
 160         let primitive = |dwarf: &mut DwarfUnit, ate| {
 161             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 162             let type_entry = dwarf.unit.get_mut(type_id);
 163             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 164             type_id
 165         };
 166
 167         let name = format!("{}", ty);
 168         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 169
 170         let type_id = match ty.kind {
 171             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 172             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 173             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 174             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 175             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 176             ty::Ref(_, pointee_ty, _mutbl)
 177             | ty::RawPtr(ty::TypeAndMut {
 178                 ty: pointee_ty,
 179                 mutbl: _mutbl,
 180             }) => {
 181                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 182
 183                 // Ensure that type is inserted before recursing to avoid duplicates
 184                 self.types.insert(ty, type_id);
 185
 186                 let pointee = self.dwarf_ty(pointee_ty);
 187
 188                 let type_entry = self.dwarf.unit.get_mut(type_id);
 189
 190                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 191                 type_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(pointee));
 192
 193                 type_id
 194             }
 195             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 196                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 197
 198                 // Ensure that type is inserted before recursing to avoid duplicates
 199                 self.types.insert(ty, type_id);
 200
 201                 let variant = adt_def.non_enum_variant();
 202
 203                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 204                     let field_offset = layout.fields.offset(field_idx);
 205                     let field_layout = layout.field(&layout::LayoutCx {
 206                         tcx: self.tcx,
 207                         param_env: ParamEnv::reveal_all(),
 208                     }, field_idx).unwrap();
 209
 210                     let field_type = self.dwarf_ty(field_layout.ty);
 211
 212                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 213                     let field_entry = self.dwarf.unit.get_mut(field_id);
 214
 215                     field_entry.set(gimli::DW_AT_name, AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()));
 216                     field_entry.set(gimli::DW_AT_data_member_location, AttributeValue::Udata(field_offset.bytes()));
 217                     field_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(field_type));
 218                 }
 219
 220                 type_id
 221             }
 222             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 223         };
 224
 225         let type_entry = self.dwarf.unit.get_mut(type_id);
 226
 227         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 228         type_entry.set(
 229             gimli::DW_AT_byte_size,
 230             AttributeValue::Udata(layout.size.bytes()),
 231         );
 232
 233         self.types.insert(ty, type_id);
 234
 235         type_id
 236     }
 237
 238     fn define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 239         let dw_ty = self.dwarf_ty(ty);
 240
 241         let var_id = self
 242             .dwarf
 243             .unit
 244             .add(scope, gimli::DW_TAG_variable);
 245         let var_entry = self.dwarf.unit.get_mut(var_id);
 246
 247         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 248         var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
 249
 250         var_id
 251     }
 252
 253     pub(crate) fn define_function(
 254         &mut self,
 255         instance: Instance<'tcx>,
 256         func_id: FuncId,
 257         name: &str,
 258         isa: &dyn TargetIsa,
 259         context: &Context,
 260         source_info_set: &indexmap::IndexSet<SourceInfo>,
 261         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 262     ) {
 263         let symbol = func_id.as_u32() as usize;
 264         let mir = self.tcx.instance_mir(instance.def);
 265
 266         // FIXME: add to appropriate scope instead of root
 267         let scope = self.dwarf.unit.root();
 268
 269         let entry_id = self
 270             .dwarf
 271             .unit
 272             .add(scope, gimli::DW_TAG_subprogram);
 273         let entry = self.dwarf.unit.get_mut(entry_id);
 274         let name_id = self.dwarf.strings.add(name);
 275         // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
 276         entry.set(
 277             gimli::DW_AT_name,
 278             AttributeValue::StringRef(name_id),
 279         );
 280         entry.set(
 281             gimli::DW_AT_linkage_name,
 282             AttributeValue::StringRef(name_id),
 283         );
 284
 285         let end = self.create_debug_lines(isa, symbol, entry_id, context, mir.span, source_info_set);
 286
 287         self
 288             .unit_range_list
 289             .0
 290             .push(Range::StartLength {
 291                 begin: Address::Symbol {
 292                     symbol,
 293                     addend: 0,
 294                 },
 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(gimli::DW_AT_low_pc, AttributeValue::Address(Address::Symbol {
 305             symbol,
 306             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.func.signature.params.iter().zip(context.func.dfg.block_params(context.func.layout.entry_block().unwrap())).enumerate() {
 313             use cranelift_codegen::ir::ArgumentPurpose;
 314             let base_name = match param.purpose {
 315                 ArgumentPurpose::Normal => "arg",
 316                 ArgumentPurpose::StructReturn => "sret",
 317                 ArgumentPurpose::Link | ArgumentPurpose::FramePointer | ArgumentPurpose::CalleeSaved => continue,
 318                 ArgumentPurpose::VMContext | ArgumentPurpose::SignatureId | ArgumentPurpose::StackLimit => unreachable!(),
 319             };
 320             let name = format!("{}{}", base_name, i);
 321
 322             let dw_ty = self.dwarf_ty_for_clif_ty(param.value_type);
 323             let loc = translate_loc(isa, context.func.locations[val], &context.func.stack_slots).unwrap();
 324
 325             let arg_id = self.dwarf.unit.add(entry_id, gimli::DW_TAG_formal_parameter);
 326             let var_entry = self.dwarf.unit.get_mut(arg_id);
 327
 328             var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 329             var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
 330             var_entry.set(gimli::DW_AT_location, AttributeValue::Exprloc(loc));
 331         }
 332
 333         // FIXME make it more reliable and implement scopes before re-enabling this.
 334         if false {
 335             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 336
 337             for (local, _local_decl) in mir.local_decls.iter_enumerated() {
 338                 let ty = self.tcx.subst_and_normalize_erasing_regions(
 339                     instance.substs,
 340                     ty::ParamEnv::reveal_all(),
 341                     &mir.local_decls[local].ty,
 342                 );
 343                 let var_id = self.define_local(entry_id, format!("{:?}", local), ty);
 344
 345                 let location = place_location(
 346                     self,
 347                     isa,
 348                     symbol,
 349                     context,
 350                     &local_map,
 351                     &value_labels_ranges,
 352                     Place {
 353                         local,
 354                         projection: ty::List::empty(),
 355                     },
 356                 );
 357
 358                 let var_entry = self.dwarf.unit.get_mut(var_id);
 359                 var_entry.set(gimli::DW_AT_location, location);
 360             }
 361         }
 362
 363         // FIXME create locals for all entries in mir.var_debug_info
 364     }
 365 }
 366
 367 fn place_location<'tcx>(
 368     debug_context: &mut DebugContext<'tcx>,
 369     isa: &dyn TargetIsa,
 370     symbol: usize,
 371     context: &Context,
 372     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 373     #[allow(rustc::default_hash_types)]
 374     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 375     place: Place<'tcx>,
 376 ) -> AttributeValue {
 377     assert!(place.projection.is_empty()); // FIXME implement them
 378
 379     match local_map[&place.local].inner() {
 380         CPlaceInner::Var(_local, var) => {
 381             let value_label = cranelift_codegen::ir::ValueLabel::new(var.index());
 382             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 383                 let loc_list = LocationList(
 384                     value_loc_ranges
 385                         .iter()
 386                         .map(|value_loc_range| Location::StartEnd {
 387                             begin: Address::Symbol {
 388                                 symbol,
 389                                 addend: i64::from(value_loc_range.start),
 390                             },
 391                             end: Address::Symbol {
 392                                 symbol,
 393                                 addend: i64::from(value_loc_range.end),
 394                             },
 395                             data: translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 396                         })
 397                         .collect(),
 398                 );
 399                 let loc_list_id = debug_context.dwarf.unit.locations.add(loc_list);
 400
 401                 AttributeValue::LocationListRef(loc_list_id)
 402             } else {
 403                 // FIXME set value labels for unused locals
 404
 405                 AttributeValue::Exprloc(Expression::new())
 406             }
 407         }
 408         CPlaceInner::VarPair(_, _, _) => {
 409             // FIXME implement this
 410
 411             AttributeValue::Exprloc(Expression::new())
 412         }
 413         CPlaceInner::Addr(_, _) => {
 414             // FIXME implement this (used by arguments and returns)
 415
 416             AttributeValue::Exprloc(Expression::new())
 417
 418             // For PointerBase::Stack:
 419             //AttributeValue::Exprloc(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap())
 420         }
 421     }
 422 }
 423
 424 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 425 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Expression> {
 426     match loc {
 427         ValueLoc::Reg(reg) => {
 428             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 429             let mut expr = Expression::new();
 430             expr.op_reg(gimli::Register(machine_reg));
 431             Some(expr)
 432         }
 433         ValueLoc::Stack(ss) => {
 434             if let Some(ss_offset) = stack_slots[ss].offset {
 435                 let mut expr = Expression::new();
 436                 expr.op_breg(X86_64::RBP, i64::from(ss_offset) + 16);
 437                 Some(expr)
 438             } else {
 439                 None
 440             }
 441         }
 442         _ => None,
 443     }
 444 }