src/debuginfo/mod.rs

   1 mod emit;
   2 mod line_info;
   3
   4 use crate::prelude::*;
   5
   6 use rustc_span::FileName;
   7
   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     self, Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
  14     LocationList, Range, RangeList, UnitEntryId, Writer,
  15 };
  16 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
  17
  18 pub(crate) use emit::{DebugReloc, DebugRelocName};
  19
  20 fn target_endian(tcx: TyCtxt<'_>) -> RunTimeEndian {
  21     use rustc_target::abi::Endian;
  22
  23     match tcx.data_layout.endian {
  24         Endian::Big => RunTimeEndian::Big,
  25         Endian::Little => RunTimeEndian::Little,
  26     }
  27 }
  28
  29 pub(crate) struct DebugContext<'tcx> {
  30     tcx: TyCtxt<'tcx>,
  31
  32     endian: RunTimeEndian,
  33     symbols: indexmap::IndexMap<FuncId, String>,
  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>, address_size: u8) -> 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,
  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                 let info = tcx.sess
  69                     .source_map()
  70                     .get_source_file(&FileName::Real(path))
  71                     .map(|f| f.src_hash)
  72                     .and_then(line_info::make_file_info);
  73                 (name, info)
  74             },
  75             None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
  76         };
  77
  78         let mut line_program = LineProgram::new(
  79             encoding,
  80             LineEncoding::default(),
  81             LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
  82             LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
  83             file_info,
  84         );
  85         line_program.file_has_md5 = file_info.is_some();
  86
  87         dwarf.unit.line_program = line_program;
  88
  89         {
  90             let name = dwarf.strings.add(name);
  91             let comp_dir = dwarf.strings.add(comp_dir);
  92
  93             let root = dwarf.unit.root();
  94             let root = dwarf.unit.get_mut(root);
  95             root.set(
  96                 gimli::DW_AT_producer,
  97                 AttributeValue::StringRef(dwarf.strings.add(producer)),
  98             );
  99             root.set(
 100                 gimli::DW_AT_language,
 101                 AttributeValue::Language(gimli::DW_LANG_Rust),
 102             );
 103             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 104             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 105             root.set(
 106                 gimli::DW_AT_low_pc,
 107                 AttributeValue::Address(Address::Constant(0)),
 108             );
 109         }
 110
 111         DebugContext {
 112             tcx,
 113
 114             endian: target_endian(tcx),
 115             symbols: indexmap::IndexMap::new(),
 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         let (symbol, _) = debug_context.symbols.insert_full(func_id, name.to_string());
 263
 264         // FIXME: add to appropriate scope intead of root
 265         let scope = debug_context.dwarf.unit.root();
 266
 267         let entry_id = debug_context
 268             .dwarf
 269             .unit
 270             .add(scope, gimli::DW_TAG_subprogram);
 271         let entry = debug_context.dwarf.unit.get_mut(entry_id);
 272         let name_id = debug_context.dwarf.strings.add(name);
 273         // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
 274         entry.set(
 275             gimli::DW_AT_name,
 276             AttributeValue::StringRef(name_id),
 277         );
 278         entry.set(
 279             gimli::DW_AT_linkage_name,
 280             AttributeValue::StringRef(name_id),
 281         );
 282
 283         FunctionDebugContext {
 284             debug_context,
 285             entry_id,
 286             symbol,
 287             instance,
 288             mir,
 289         }
 290     }
 291
 292     fn define_local(&mut self, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 293         let dw_ty = self.debug_context.dwarf_ty(ty);
 294
 295         let var_id = self
 296             .debug_context
 297             .dwarf
 298             .unit
 299             .add(self.entry_id, gimli::DW_TAG_variable);
 300         let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 301
 302         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 303         var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 304
 305         var_id
 306     }
 307
 308     pub(crate) fn define(
 309         &mut self,
 310         context: &Context,
 311         isa: &dyn TargetIsa,
 312         source_info_set: &indexmap::IndexSet<SourceInfo>,
 313         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 314     ) {
 315         if isa.get_mach_backend().is_some() {
 316             return; // The AArch64 backend doesn't support line debuginfo yet.
 317         }
 318
 319         let end = self.create_debug_lines(context, isa, source_info_set);
 320
 321         self.debug_context
 322             .unit_range_list
 323             .0
 324             .push(Range::StartLength {
 325                 begin: Address::Symbol {
 326                     symbol: self.symbol,
 327                     addend: 0,
 328                 },
 329                 length: u64::from(end),
 330             });
 331
 332         let func_entry = self.debug_context.dwarf.unit.get_mut(self.entry_id);
 333         // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
 334         func_entry.set(gimli::DW_AT_low_pc, AttributeValue::Address(Address::Symbol {
 335             symbol: self.symbol,
 336             addend: 0,
 337         }));
 338         // Using Udata for DW_AT_high_pc requires at least DWARF4
 339         func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
 340
 341         // FIXME Remove once actual debuginfo for locals works.
 342         for (i, (param, &val)) in context.func.signature.params.iter().zip(context.func.dfg.block_params(context.func.layout.entry_block().unwrap())).enumerate() {
 343             use cranelift_codegen::ir::ArgumentPurpose;
 344             let base_name = match param.purpose {
 345                 ArgumentPurpose::Normal => "arg",
 346                 ArgumentPurpose::StructReturn => "sret",
 347                 ArgumentPurpose::Link | ArgumentPurpose::FramePointer | ArgumentPurpose::CalleeSaved => continue,
 348                 ArgumentPurpose::VMContext | ArgumentPurpose::SignatureId | ArgumentPurpose::StackLimit => unreachable!(),
 349             };
 350             let name = format!("{}{}", base_name, i);
 351
 352             let dw_ty = self.debug_context.dwarf_ty_for_clif_ty(param.value_type);
 353             let loc = Expression(
 354                 translate_loc(isa, context.func.locations[val], &context.func.stack_slots).unwrap(),
 355             );
 356
 357             let arg_id = self.debug_context.dwarf.unit.add(self.entry_id, gimli::DW_TAG_formal_parameter);
 358             let var_entry = self.debug_context.dwarf.unit.get_mut(arg_id);
 359
 360             var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 361             var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 362             var_entry.set(gimli::DW_AT_location, AttributeValue::Exprloc(loc));
 363         }
 364
 365         // FIXME make it more reliable and implement scopes before re-enabling this.
 366         if false {
 367             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 368
 369             for (local, _local_decl) in self.mir.local_decls.iter_enumerated() {
 370                 let ty = self.debug_context.tcx.subst_and_normalize_erasing_regions(
 371                     self.instance.substs,
 372                     ty::ParamEnv::reveal_all(),
 373                     &self.mir.local_decls[local].ty,
 374                 );
 375                 let var_id = self.define_local(format!("{:?}", local), ty);
 376
 377                 let location = place_location(
 378                     self,
 379                     isa,
 380                     context,
 381                     &local_map,
 382                     &value_labels_ranges,
 383                     Place {
 384                         local,
 385                         projection: ty::List::empty(),
 386                     },
 387                 );
 388
 389                 let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 390                 var_entry.set(gimli::DW_AT_location, location);
 391             }
 392         }
 393
 394         // FIXME create locals for all entries in mir.var_debug_info
 395     }
 396 }
 397
 398 fn place_location<'a, 'tcx>(
 399     func_debug_ctx: &mut FunctionDebugContext<'a, 'tcx>,
 400     isa: &dyn TargetIsa,
 401     context: &Context,
 402     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 403     #[allow(rustc::default_hash_types)]
 404     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 405     place: Place<'tcx>,
 406 ) -> AttributeValue {
 407     assert!(place.projection.is_empty()); // FIXME implement them
 408
 409     match local_map[&place.local].inner() {
 410         CPlaceInner::Var(local) => {
 411             let value_label = cranelift_codegen::ir::ValueLabel::from_u32(local.as_u32());
 412             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 413                 let loc_list = LocationList(
 414                     value_loc_ranges
 415                         .iter()
 416                         .map(|value_loc_range| Location::StartEnd {
 417                             begin: Address::Symbol {
 418                                 symbol: func_debug_ctx.symbol,
 419                                 addend: i64::from(value_loc_range.start),
 420                             },
 421                             end: Address::Symbol {
 422                                 symbol: func_debug_ctx.symbol,
 423                                 addend: i64::from(value_loc_range.end),
 424                             },
 425                             data: Expression(
 426                                 translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 427                             ),
 428                         })
 429                         .collect(),
 430                 );
 431                 let loc_list_id = func_debug_ctx.debug_context.dwarf.unit.locations.add(loc_list);
 432
 433                 AttributeValue::LocationListRef(loc_list_id)
 434             } else {
 435                 // FIXME set value labels for unused locals
 436
 437                 AttributeValue::Exprloc(Expression(vec![]))
 438             }
 439         }
 440         CPlaceInner::Addr(_, _) => {
 441             // FIXME implement this (used by arguments and returns)
 442
 443             AttributeValue::Exprloc(Expression(vec![]))
 444
 445             // For PointerBase::Stack:
 446             //AttributeValue::Exprloc(Expression(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap()))
 447         }
 448     }
 449 }
 450
 451 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 452 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Vec<u8>> {
 453     match loc {
 454         ValueLoc::Reg(reg) => {
 455             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 456             assert!(machine_reg <= 32); // FIXME
 457             Some(vec![gimli::constants::DW_OP_reg0.0 + machine_reg as u8])
 458         }
 459         ValueLoc::Stack(ss) => {
 460             if let Some(ss_offset) = stack_slots[ss].offset {
 461                 let endian = gimli::RunTimeEndian::Little;
 462                 let mut writer = write::EndianVec::new(endian);
 463                 writer
 464                     .write_u8(gimli::constants::DW_OP_breg0.0 + X86_64::RBP.0 as u8)
 465                     .expect("bp wr");
 466                 writer.write_sleb128(ss_offset as i64 + 16).expect("ss wr");
 467                 let buf = writer.into_vec();
 468                 return Some(buf);
 469             }
 470             None
 471         }
 472         _ => None,
 473     }
 474 }