src/debuginfo/mod.rs

   1 mod emit;
   2 mod line_info;
   3
   4 use crate::prelude::*;
   5
   6 use rustc_span::{FileName, SourceFileHash, SourceFileHashAlgorithm};
   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, FileInfo,
  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 const MD5_LEN: usize = 16;
  30
  31 pub(crate) struct DebugContext<'tcx> {
  32     tcx: TyCtxt<'tcx>,
  33
  34     endian: RunTimeEndian,
  35     symbols: indexmap::IndexMap<FuncId, String>,
  36
  37     dwarf: DwarfUnit,
  38     unit_range_list: RangeList,
  39
  40     types: FxHashMap<Ty<'tcx>, UnitEntryId>,
  41 }
  42
  43 impl<'tcx> DebugContext<'tcx> {
  44     pub(crate) fn new(tcx: TyCtxt<'tcx>, address_size: u8) -> 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: 5,
  51             address_size,
  52         };
  53
  54         let mut dwarf = DwarfUnit::new(encoding);
  55
  56         // FIXME: how to get version when building out of tree?
  57         // Normally this would use option_env!("CFG_VERSION").
  58         let producer = format!("cg_clif (rustc {})", "unknown version");
  59         let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
  60         let (name, md5) = match tcx.sess.local_crate_source_file.clone() {
  61             Some(path) => {
  62                 let name = path.to_string_lossy().into_owned();
  63                 let hash = tcx.sess
  64                     .source_map()
  65                     .get_source_file(&FileName::Real(path))
  66                     .map(|f| f.src_hash)
  67                     .filter(|h| matches!(h, SourceFileHash { kind: SourceFileHashAlgorithm::Md5, .. }))
  68                     .map(|h| {
  69                         let mut buf = [0u8; MD5_LEN];
  70                         buf.copy_from_slice(h.hash_bytes());
  71                         buf
  72                     });
  73                 (name, hash)
  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             Some(FileInfo {
  84                 timestamp: 0,
  85                 size: 0,
  86                 md5: md5.unwrap_or_default(),
  87             }),
  88         );
  89         line_program.file_has_md5 = md5.is_some();
  90
  91         dwarf.unit.line_program = line_program;
  92
  93         {
  94             let name = dwarf.strings.add(name);
  95             let comp_dir = dwarf.strings.add(comp_dir);
  96
  97             let root = dwarf.unit.root();
  98             let root = dwarf.unit.get_mut(root);
  99             root.set(
 100                 gimli::DW_AT_producer,
 101                 AttributeValue::StringRef(dwarf.strings.add(producer)),
 102             );
 103             root.set(
 104                 gimli::DW_AT_language,
 105                 AttributeValue::Language(gimli::DW_LANG_Rust),
 106             );
 107             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 108             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 109             root.set(
 110                 gimli::DW_AT_low_pc,
 111                 AttributeValue::Address(Address::Constant(0)),
 112             );
 113         }
 114
 115         DebugContext {
 116             tcx,
 117
 118             endian: target_endian(tcx),
 119             symbols: indexmap::IndexMap::new(),
 120
 121             dwarf,
 122             unit_range_list: RangeList(Vec::new()),
 123
 124             types: FxHashMap::default(),
 125         }
 126     }
 127
 128     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 129         if let Some(type_id) = self.types.get(ty) {
 130             return *type_id;
 131         }
 132
 133         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 134
 135         let primitive = |dwarf: &mut DwarfUnit, ate| {
 136             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 137             let type_entry = dwarf.unit.get_mut(type_id);
 138             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 139             type_id
 140         };
 141
 142         let name = format!("{}", ty);
 143         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 144
 145         let type_id = match ty.kind {
 146             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 147             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 148             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 149             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 150             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 151             ty::Ref(_, pointee_ty, _mutbl)
 152             | ty::RawPtr(ty::TypeAndMut {
 153                 ty: pointee_ty,
 154                 mutbl: _mutbl,
 155             }) => {
 156                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 157
 158                 // Ensure that type is inserted before recursing to avoid duplicates
 159                 self.types.insert(ty, type_id);
 160
 161                 let pointee = self.dwarf_ty(pointee_ty);
 162
 163                 let type_entry = self.dwarf.unit.get_mut(type_id);
 164
 165                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 166                 type_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(pointee));
 167
 168                 type_id
 169             }
 170             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 171                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 172
 173                 // Ensure that type is inserted before recursing to avoid duplicates
 174                 self.types.insert(ty, type_id);
 175
 176                 let variant = adt_def.non_enum_variant();
 177
 178                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 179                     let field_offset = layout.fields.offset(field_idx);
 180                     let field_layout = layout.field(&layout::LayoutCx {
 181                         tcx: self.tcx,
 182                         param_env: ParamEnv::reveal_all(),
 183                     }, field_idx).unwrap();
 184
 185                     let field_type = self.dwarf_ty(field_layout.ty);
 186
 187                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 188                     let field_entry = self.dwarf.unit.get_mut(field_id);
 189
 190                     field_entry.set(gimli::DW_AT_name, AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()));
 191                     field_entry.set(gimli::DW_AT_data_member_location, AttributeValue::Udata(field_offset.bytes()));
 192                     field_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(field_type));
 193                 }
 194
 195                 type_id
 196             }
 197             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 198         };
 199
 200         let type_entry = self.dwarf.unit.get_mut(type_id);
 201
 202         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 203         type_entry.set(
 204             gimli::DW_AT_byte_size,
 205             AttributeValue::Udata(layout.size.bytes()),
 206         );
 207
 208         self.types.insert(ty, type_id);
 209
 210         type_id
 211     }
 212 }
 213
 214 pub(crate) struct FunctionDebugContext<'a, 'tcx> {
 215     debug_context: &'a mut DebugContext<'tcx>,
 216     entry_id: UnitEntryId,
 217     symbol: usize,
 218     instance: Instance<'tcx>,
 219     mir: &'tcx mir::Body<'tcx>,
 220 }
 221
 222 impl<'a, 'tcx> FunctionDebugContext<'a, 'tcx> {
 223     pub(crate) fn new(
 224         debug_context: &'a mut DebugContext<'tcx>,
 225         instance: Instance<'tcx>,
 226         func_id: FuncId,
 227         name: &str,
 228     ) -> Self {
 229         let mir = *debug_context.tcx.instance_mir(instance.def);
 230
 231         let (symbol, _) = debug_context.symbols.insert_full(func_id, name.to_string());
 232
 233         // FIXME: add to appropriate scope intead of root
 234         let scope = debug_context.dwarf.unit.root();
 235
 236         let entry_id = debug_context
 237             .dwarf
 238             .unit
 239             .add(scope, gimli::DW_TAG_subprogram);
 240         let entry = debug_context.dwarf.unit.get_mut(entry_id);
 241         let name_id = debug_context.dwarf.strings.add(name);
 242         entry.set(
 243             gimli::DW_AT_linkage_name,
 244             AttributeValue::StringRef(name_id),
 245         );
 246
 247         FunctionDebugContext {
 248             debug_context,
 249             entry_id,
 250             symbol,
 251             instance,
 252             mir,
 253         }
 254     }
 255
 256     fn define_local(&mut self, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 257         let ty = self.debug_context.tcx.subst_and_normalize_erasing_regions(
 258             self.instance.substs,
 259             ty::ParamEnv::reveal_all(),
 260             &ty,
 261         );
 262         let dw_ty = self.debug_context.dwarf_ty(ty);
 263
 264         let var_id = self
 265             .debug_context
 266             .dwarf
 267             .unit
 268             .add(self.entry_id, gimli::DW_TAG_variable);
 269         let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 270
 271         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 272         var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 273
 274         var_id
 275     }
 276
 277     pub(crate) fn define(
 278         &mut self,
 279         context: &Context,
 280         isa: &dyn TargetIsa,
 281         source_info_set: &indexmap::IndexSet<SourceInfo>,
 282         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 283     ) {
 284         let end = self.create_debug_lines(context, isa, source_info_set);
 285
 286         self.debug_context
 287             .unit_range_list
 288             .0
 289             .push(Range::StartLength {
 290                 begin: Address::Symbol {
 291                     symbol: self.symbol,
 292                     addend: 0,
 293                 },
 294                 length: end as u64,
 295             });
 296
 297         // FIXME make it more reliable and implement scopes before re-enabling this.
 298         if false {
 299             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 300
 301             for (local, _local_decl) in self.mir.local_decls.iter_enumerated() {
 302                 let var_id = self.define_local(format!("{:?}", local), &self.mir.local_decls[local].ty);
 303
 304                 let location = place_location(
 305                     self,
 306                     isa,
 307                     context,
 308                     &local_map,
 309                     &value_labels_ranges,
 310                     Place {
 311                         local,
 312                         projection: ty::List::empty(),
 313                     },
 314                 );
 315
 316                 let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 317                 var_entry.set(gimli::DW_AT_location, location);
 318             }
 319         }
 320
 321         // FIXME create locals for all entries in mir.var_debug_info
 322     }
 323 }
 324
 325 fn place_location<'a, 'tcx>(
 326     func_debug_ctx: &mut FunctionDebugContext<'a, 'tcx>,
 327     isa: &dyn TargetIsa,
 328     context: &Context,
 329     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 330     #[allow(rustc::default_hash_types)]
 331     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 332     place: Place<'tcx>,
 333 ) -> AttributeValue {
 334     assert!(place.projection.is_empty()); // FIXME implement them
 335
 336     match local_map[&place.local].inner() {
 337         CPlaceInner::Var(local) => {
 338             let value_label = cranelift_codegen::ir::ValueLabel::from_u32(local.as_u32());
 339             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 340                 let loc_list = LocationList(
 341                     value_loc_ranges
 342                         .iter()
 343                         .map(|value_loc_range| Location::StartEnd {
 344                             begin: Address::Symbol {
 345                                 symbol: func_debug_ctx.symbol,
 346                                 addend: i64::from(value_loc_range.start),
 347                             },
 348                             end: Address::Symbol {
 349                                 symbol: func_debug_ctx.symbol,
 350                                 addend: i64::from(value_loc_range.end),
 351                             },
 352                             data: Expression(
 353                                 translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 354                             ),
 355                         })
 356                         .collect(),
 357                 );
 358                 let loc_list_id = func_debug_ctx.debug_context.dwarf.unit.locations.add(loc_list);
 359
 360                 AttributeValue::LocationListRef(loc_list_id)
 361             } else {
 362                 // FIXME set value labels for unused locals
 363
 364                 AttributeValue::Exprloc(Expression(vec![]))
 365             }
 366         }
 367         CPlaceInner::Addr(_, _) => {
 368             // FIXME implement this (used by arguments and returns)
 369
 370             AttributeValue::Exprloc(Expression(vec![]))
 371
 372             // For PointerBase::Stack:
 373             //AttributeValue::Exprloc(Expression(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap()))
 374         }
 375     }
 376 }
 377
 378 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 379 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Vec<u8>> {
 380     match loc {
 381         ValueLoc::Reg(reg) => {
 382             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 383             assert!(machine_reg <= 32); // FIXME
 384             Some(vec![gimli::constants::DW_OP_reg0.0 + machine_reg as u8])
 385         }
 386         ValueLoc::Stack(ss) => {
 387             if let Some(ss_offset) = stack_slots[ss].offset {
 388                 let endian = gimli::RunTimeEndian::Little;
 389                 let mut writer = write::EndianVec::new(endian);
 390                 writer
 391                     .write_u8(gimli::constants::DW_OP_breg0.0 + X86_64::RBP.0 as u8)
 392                     .expect("bp wr");
 393                 writer.write_sleb128(ss_offset as i64 + 16).expect("ss wr");
 394                 let buf = writer.into_vec();
 395                 return Some(buf);
 396             }
 397             None
 398         }
 399         _ => None,
 400     }
 401 }