src/debuginfo/mod.rs

   1 mod emit;
   2 mod line_info;
   3 mod unwind;
   4
   5 use crate::prelude::*;
   6
   7 use rustc_span::FileName;
   8
   9 use cranelift_codegen::ir::{StackSlots, ValueLabel, ValueLoc};
  10 use cranelift_codegen::isa::TargetIsa;
  11 use cranelift_codegen::ValueLocRange;
  12
  13 use gimli::write::{
  14     self, Address, AttributeValue, DwarfUnit, Expression, LineProgram,
  15     LineString, Location, LocationList, Range, RangeList, UnitEntryId, Writer,
  16 };
  17 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
  18
  19 pub(crate) use emit::{DebugReloc, DebugRelocName};
  20 pub(crate) use unwind::UnwindContext;
  21
  22 fn target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian {
  23     use rustc_target::abi::Endian;
  24
  25     match tcx.data_layout.endian {
  26         Endian::Big => RunTimeEndian::Big,
  27         Endian::Little => RunTimeEndian::Little,
  28     }
  29 }
  30
  31 pub(crate) struct DebugContext<'tcx> {
  32     tcx: TyCtxt<'tcx>,
  33
  34     endian: RunTimeEndian,
  35
  36     dwarf: DwarfUnit,
  37     unit_range_list: RangeList,
  38
  39     clif_types: FxHashMap<Type, UnitEntryId>,
  40     types: FxHashMap<Ty<'tcx>, UnitEntryId>,
  41 }
  42
  43 impl<'tcx> DebugContext<'tcx> {
  44     pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
  45         let encoding = Encoding {
  46             format: Format::Dwarf32,
  47             // TODO: this should be configurable
  48             // macOS doesn't seem to support DWARF > 3
  49             // 5 version is required for md5 file hash
  50             version: if tcx.sess.target.target.options.is_like_osx {
  51                 3
  52             } else {
  53                 // FIXME change to version 5 once the gdb and lldb shipping with the latest debian
  54                 // support it.
  55                 4
  56             },
  57             address_size: isa.frontend_config().pointer_bytes(),
  58         };
  59
  60         let mut dwarf = DwarfUnit::new(encoding);
  61
  62         // FIXME: how to get version when building out of tree?
  63         // Normally this would use option_env!("CFG_VERSION").
  64         let producer = format!("cg_clif (rustc {})", "unknown version");
  65         let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
  66         let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
  67             Some(path) => {
  68                 let name = path.to_string_lossy().into_owned();
  69                 let info = tcx.sess
  70                     .source_map()
  71                     .get_source_file(&FileName::Real(path))
  72                     .map(|f| f.src_hash)
  73                     .and_then(line_info::make_file_info);
  74                 (name, info)
  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(
  97                 gimli::DW_AT_producer,
  98                 AttributeValue::StringRef(dwarf.strings.add(producer)),
  99             );
 100             root.set(
 101                 gimli::DW_AT_language,
 102                 AttributeValue::Language(gimli::DW_LANG_Rust),
 103             );
 104             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 105             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 106             root.set(
 107                 gimli::DW_AT_low_pc,
 108                 AttributeValue::Address(Address::Constant(0)),
 109             );
 110         }
 111
 112         DebugContext {
 113             tcx,
 114
 115             endian: target_endian(tcx),
 116
 117             dwarf,
 118             unit_range_list: RangeList(Vec::new()),
 119
 120             clif_types: FxHashMap::default(),
 121             types: FxHashMap::default(),
 122         }
 123     }
 124
 125     fn dwarf_ty_for_clif_ty(&mut self, ty: Type) -> UnitEntryId {
 126         if let Some(type_id) = self.clif_types.get(&ty) {
 127             return *type_id;
 128         }
 129
 130         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 131
 132         let primitive = |dwarf: &mut DwarfUnit, ate| {
 133             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 134             let type_entry = dwarf.unit.get_mut(type_id);
 135             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 136             type_id
 137         };
 138
 139         let type_id = if ty.is_bool() {
 140             primitive(&mut self.dwarf, gimli::DW_ATE_boolean)
 141         } else if ty.is_int() {
 142             primitive(&mut self.dwarf, gimli::DW_ATE_address)
 143         } else if ty.is_float() {
 144             primitive(&mut self.dwarf, gimli::DW_ATE_float)
 145         } else {
 146             new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type)
 147         };
 148
 149         let type_entry = self.dwarf.unit.get_mut(type_id);
 150         type_entry.set(gimli::DW_AT_name, AttributeValue::String(format!("{}", ty).replace('i', "u").into_bytes()));
 151         type_entry.set(
 152             gimli::DW_AT_byte_size,
 153             AttributeValue::Udata(u64::from(ty.bytes())),
 154         );
 155
 156         type_id
 157     }
 158
 159     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 160         if let Some(type_id) = self.types.get(ty) {
 161             return *type_id;
 162         }
 163
 164         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 165
 166         let primitive = |dwarf: &mut DwarfUnit, ate| {
 167             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 168             let type_entry = dwarf.unit.get_mut(type_id);
 169             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 170             type_id
 171         };
 172
 173         let name = format!("{}", ty);
 174         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 175
 176         let type_id = match ty.kind {
 177             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 178             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 179             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 180             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 181             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 182             ty::Ref(_, pointee_ty, _mutbl)
 183             | ty::RawPtr(ty::TypeAndMut {
 184                 ty: pointee_ty,
 185                 mutbl: _mutbl,
 186             }) => {
 187                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 188
 189                 // Ensure that type is inserted before recursing to avoid duplicates
 190                 self.types.insert(ty, type_id);
 191
 192                 let pointee = self.dwarf_ty(pointee_ty);
 193
 194                 let type_entry = self.dwarf.unit.get_mut(type_id);
 195
 196                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 197                 type_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(pointee));
 198
 199                 type_id
 200             }
 201             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 202                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 203
 204                 // Ensure that type is inserted before recursing to avoid duplicates
 205                 self.types.insert(ty, type_id);
 206
 207                 let variant = adt_def.non_enum_variant();
 208
 209                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 210                     let field_offset = layout.fields.offset(field_idx);
 211                     let field_layout = layout.field(&layout::LayoutCx {
 212                         tcx: self.tcx,
 213                         param_env: ParamEnv::reveal_all(),
 214                     }, field_idx).unwrap();
 215
 216                     let field_type = self.dwarf_ty(field_layout.ty);
 217
 218                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 219                     let field_entry = self.dwarf.unit.get_mut(field_id);
 220
 221                     field_entry.set(gimli::DW_AT_name, AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()));
 222                     field_entry.set(gimli::DW_AT_data_member_location, AttributeValue::Udata(field_offset.bytes()));
 223                     field_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(field_type));
 224                 }
 225
 226                 type_id
 227             }
 228             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 229         };
 230
 231         let type_entry = self.dwarf.unit.get_mut(type_id);
 232
 233         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 234         type_entry.set(
 235             gimli::DW_AT_byte_size,
 236             AttributeValue::Udata(layout.size.bytes()),
 237         );
 238
 239         self.types.insert(ty, type_id);
 240
 241         type_id
 242     }
 243 }
 244
 245 pub(crate) struct FunctionDebugContext<'a, 'tcx> {
 246     debug_context: &'a mut DebugContext<'tcx>,
 247     entry_id: UnitEntryId,
 248     symbol: usize,
 249     instance: Instance<'tcx>,
 250     mir: &'tcx mir::Body<'tcx>,
 251 }
 252
 253 impl<'a, 'tcx> FunctionDebugContext<'a, 'tcx> {
 254     pub(crate) fn new(
 255         debug_context: &'a mut DebugContext<'tcx>,
 256         instance: Instance<'tcx>,
 257         func_id: FuncId,
 258         name: &str,
 259     ) -> Self {
 260         let mir = debug_context.tcx.instance_mir(instance.def);
 261
 262         // FIXME: add to appropriate scope intead of root
 263         let scope = debug_context.dwarf.unit.root();
 264
 265         let entry_id = debug_context
 266             .dwarf
 267             .unit
 268             .add(scope, gimli::DW_TAG_subprogram);
 269         let entry = debug_context.dwarf.unit.get_mut(entry_id);
 270         let name_id = debug_context.dwarf.strings.add(name);
 271         // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
 272         entry.set(
 273             gimli::DW_AT_name,
 274             AttributeValue::StringRef(name_id),
 275         );
 276         entry.set(
 277             gimli::DW_AT_linkage_name,
 278             AttributeValue::StringRef(name_id),
 279         );
 280
 281         FunctionDebugContext {
 282             debug_context,
 283             entry_id,
 284             symbol: func_id.as_u32() as usize,
 285             instance,
 286             mir,
 287         }
 288     }
 289
 290     fn define_local(&mut self, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 291         let dw_ty = self.debug_context.dwarf_ty(ty);
 292
 293         let var_id = self
 294             .debug_context
 295             .dwarf
 296             .unit
 297             .add(self.entry_id, gimli::DW_TAG_variable);
 298         let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 299
 300         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 301         var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 302
 303         var_id
 304     }
 305
 306     pub(crate) fn define(
 307         &mut self,
 308         context: &Context,
 309         isa: &dyn TargetIsa,
 310         source_info_set: &indexmap::IndexSet<SourceInfo>,
 311         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 312     ) {
 313         let end = self.create_debug_lines(context, isa, source_info_set);
 314
 315         self.debug_context
 316             .unit_range_list
 317             .0
 318             .push(Range::StartLength {
 319                 begin: Address::Symbol {
 320                     symbol: self.symbol,
 321                     addend: 0,
 322                 },
 323                 length: u64::from(end),
 324             });
 325
 326         if isa.get_mach_backend().is_some() {
 327             return; // Not yet implemented for the AArch64 backend.
 328         }
 329
 330         let func_entry = self.debug_context.dwarf.unit.get_mut(self.entry_id);
 331         // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
 332         func_entry.set(gimli::DW_AT_low_pc, AttributeValue::Address(Address::Symbol {
 333             symbol: self.symbol,
 334             addend: 0,
 335         }));
 336         // Using Udata for DW_AT_high_pc requires at least DWARF4
 337         func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
 338
 339         // FIXME Remove once actual debuginfo for locals works.
 340         for (i, (param, &val)) in context.func.signature.params.iter().zip(context.func.dfg.block_params(context.func.layout.entry_block().unwrap())).enumerate() {
 341             use cranelift_codegen::ir::ArgumentPurpose;
 342             let base_name = match param.purpose {
 343                 ArgumentPurpose::Normal => "arg",
 344                 ArgumentPurpose::StructReturn => "sret",
 345                 ArgumentPurpose::Link | ArgumentPurpose::FramePointer | ArgumentPurpose::CalleeSaved => continue,
 346                 ArgumentPurpose::VMContext | ArgumentPurpose::SignatureId | ArgumentPurpose::StackLimit => unreachable!(),
 347             };
 348             let name = format!("{}{}", base_name, i);
 349
 350             let dw_ty = self.debug_context.dwarf_ty_for_clif_ty(param.value_type);
 351             let loc = Expression(
 352                 translate_loc(isa, context.func.locations[val], &context.func.stack_slots).unwrap(),
 353             );
 354
 355             let arg_id = self.debug_context.dwarf.unit.add(self.entry_id, gimli::DW_TAG_formal_parameter);
 356             let var_entry = self.debug_context.dwarf.unit.get_mut(arg_id);
 357
 358             var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 359             var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 360             var_entry.set(gimli::DW_AT_location, AttributeValue::Exprloc(loc));
 361         }
 362
 363         // FIXME make it more reliable and implement scopes before re-enabling this.
 364         if false {
 365             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 366
 367             for (local, _local_decl) in self.mir.local_decls.iter_enumerated() {
 368                 let ty = self.debug_context.tcx.subst_and_normalize_erasing_regions(
 369                     self.instance.substs,
 370                     ty::ParamEnv::reveal_all(),
 371                     &self.mir.local_decls[local].ty,
 372                 );
 373                 let var_id = self.define_local(format!("{:?}", local), ty);
 374
 375                 let location = place_location(
 376                     self,
 377                     isa,
 378                     context,
 379                     &local_map,
 380                     &value_labels_ranges,
 381                     Place {
 382                         local,
 383                         projection: ty::List::empty(),
 384                     },
 385                 );
 386
 387                 let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 388                 var_entry.set(gimli::DW_AT_location, location);
 389             }
 390         }
 391
 392         // FIXME create locals for all entries in mir.var_debug_info
 393     }
 394 }
 395
 396 fn place_location<'a, 'tcx>(
 397     func_debug_ctx: &mut FunctionDebugContext<'a, 'tcx>,
 398     isa: &dyn TargetIsa,
 399     context: &Context,
 400     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 401     #[allow(rustc::default_hash_types)]
 402     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 403     place: Place<'tcx>,
 404 ) -> AttributeValue {
 405     assert!(place.projection.is_empty()); // FIXME implement them
 406
 407     match local_map[&place.local].inner() {
 408         CPlaceInner::Var(local) => {
 409             let value_label = cranelift_codegen::ir::ValueLabel::from_u32(local.as_u32());
 410             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 411                 let loc_list = LocationList(
 412                     value_loc_ranges
 413                         .iter()
 414                         .map(|value_loc_range| Location::StartEnd {
 415                             begin: Address::Symbol {
 416                                 symbol: func_debug_ctx.symbol,
 417                                 addend: i64::from(value_loc_range.start),
 418                             },
 419                             end: Address::Symbol {
 420                                 symbol: func_debug_ctx.symbol,
 421                                 addend: i64::from(value_loc_range.end),
 422                             },
 423                             data: Expression(
 424                                 translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 425                             ),
 426                         })
 427                         .collect(),
 428                 );
 429                 let loc_list_id = func_debug_ctx.debug_context.dwarf.unit.locations.add(loc_list);
 430
 431                 AttributeValue::LocationListRef(loc_list_id)
 432             } else {
 433                 // FIXME set value labels for unused locals
 434
 435                 AttributeValue::Exprloc(Expression(vec![]))
 436             }
 437         }
 438         CPlaceInner::Addr(_, _) => {
 439             // FIXME implement this (used by arguments and returns)
 440
 441             AttributeValue::Exprloc(Expression(vec![]))
 442
 443             // For PointerBase::Stack:
 444             //AttributeValue::Exprloc(Expression(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap()))
 445         }
 446     }
 447 }
 448
 449 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 450 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Vec<u8>> {
 451     match loc {
 452         ValueLoc::Reg(reg) => {
 453             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 454             assert!(machine_reg <= 32); // FIXME
 455             Some(vec![gimli::constants::DW_OP_reg0.0 + machine_reg as u8])
 456         }
 457         ValueLoc::Stack(ss) => {
 458             if let Some(ss_offset) = stack_slots[ss].offset {
 459                 let endian = gimli::RunTimeEndian::Little;
 460                 let mut writer = write::EndianVec::new(endian);
 461                 writer
 462                     .write_u8(gimli::constants::DW_OP_breg0.0 + X86_64::RBP.0 as u8)
 463                     .expect("bp wr");
 464                 writer.write_sleb128(ss_offset as i64 + 16).expect("ss wr");
 465                 let buf = writer.into_vec();
 466                 return Some(buf);
 467             }
 468             None
 469         }
 470         _ => None,
 471     }
 472 }