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: if tcx.sess.target.target.options.is_like_osx {
  51                 3
  52             } else {
  53                 5
  54             },
  55             address_size,
  56         };
  57
  58         let mut dwarf = DwarfUnit::new(encoding);
  59
  60         // FIXME: how to get version when building out of tree?
  61         // Normally this would use option_env!("CFG_VERSION").
  62         let producer = format!("cg_clif (rustc {})", "unknown version");
  63         let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
  64         let (name, md5) = match tcx.sess.local_crate_source_file.clone() {
  65             Some(path) => {
  66                 let name = path.to_string_lossy().into_owned();
  67                 let hash = tcx.sess
  68                     .source_map()
  69                     .get_source_file(&FileName::Real(path))
  70                     .map(|f| f.src_hash)
  71                     .filter(|h| matches!(h, SourceFileHash { kind: SourceFileHashAlgorithm::Md5, .. }))
  72                     .map(|h| {
  73                         let mut buf = [0u8; MD5_LEN];
  74                         buf.copy_from_slice(h.hash_bytes());
  75                         buf
  76                     });
  77                 (name, hash)
  78             },
  79             None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
  80         };
  81
  82         let mut line_program = LineProgram::new(
  83             encoding,
  84             LineEncoding::default(),
  85             LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
  86             LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
  87             Some(FileInfo {
  88                 timestamp: 0,
  89                 size: 0,
  90                 md5: md5.unwrap_or_default(),
  91             }),
  92         );
  93         line_program.file_has_md5 = md5.is_some();
  94
  95         dwarf.unit.line_program = line_program;
  96
  97         {
  98             let name = dwarf.strings.add(name);
  99             let comp_dir = dwarf.strings.add(comp_dir);
 100
 101             let root = dwarf.unit.root();
 102             let root = dwarf.unit.get_mut(root);
 103             root.set(
 104                 gimli::DW_AT_producer,
 105                 AttributeValue::StringRef(dwarf.strings.add(producer)),
 106             );
 107             root.set(
 108                 gimli::DW_AT_language,
 109                 AttributeValue::Language(gimli::DW_LANG_Rust),
 110             );
 111             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 112             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 113             root.set(
 114                 gimli::DW_AT_low_pc,
 115                 AttributeValue::Address(Address::Constant(0)),
 116             );
 117         }
 118
 119         DebugContext {
 120             tcx,
 121
 122             endian: target_endian(tcx),
 123             symbols: indexmap::IndexMap::new(),
 124
 125             dwarf,
 126             unit_range_list: RangeList(Vec::new()),
 127
 128             types: FxHashMap::default(),
 129         }
 130     }
 131
 132     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 133         if let Some(type_id) = self.types.get(ty) {
 134             return *type_id;
 135         }
 136
 137         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 138
 139         let primitive = |dwarf: &mut DwarfUnit, ate| {
 140             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 141             let type_entry = dwarf.unit.get_mut(type_id);
 142             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 143             type_id
 144         };
 145
 146         let name = format!("{}", ty);
 147         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 148
 149         let type_id = match ty.kind {
 150             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 151             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 152             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 153             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 154             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 155             ty::Ref(_, pointee_ty, _mutbl)
 156             | ty::RawPtr(ty::TypeAndMut {
 157                 ty: pointee_ty,
 158                 mutbl: _mutbl,
 159             }) => {
 160                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 161
 162                 // Ensure that type is inserted before recursing to avoid duplicates
 163                 self.types.insert(ty, type_id);
 164
 165                 let pointee = self.dwarf_ty(pointee_ty);
 166
 167                 let type_entry = self.dwarf.unit.get_mut(type_id);
 168
 169                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 170                 type_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(pointee));
 171
 172                 type_id
 173             }
 174             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 175                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 176
 177                 // Ensure that type is inserted before recursing to avoid duplicates
 178                 self.types.insert(ty, type_id);
 179
 180                 let variant = adt_def.non_enum_variant();
 181
 182                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 183                     let field_offset = layout.fields.offset(field_idx);
 184                     let field_layout = layout.field(&layout::LayoutCx {
 185                         tcx: self.tcx,
 186                         param_env: ParamEnv::reveal_all(),
 187                     }, field_idx).unwrap();
 188
 189                     let field_type = self.dwarf_ty(field_layout.ty);
 190
 191                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 192                     let field_entry = self.dwarf.unit.get_mut(field_id);
 193
 194                     field_entry.set(gimli::DW_AT_name, AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()));
 195                     field_entry.set(gimli::DW_AT_data_member_location, AttributeValue::Udata(field_offset.bytes()));
 196                     field_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(field_type));
 197                 }
 198
 199                 type_id
 200             }
 201             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 202         };
 203
 204         let type_entry = self.dwarf.unit.get_mut(type_id);
 205
 206         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 207         type_entry.set(
 208             gimli::DW_AT_byte_size,
 209             AttributeValue::Udata(layout.size.bytes()),
 210         );
 211
 212         self.types.insert(ty, type_id);
 213
 214         type_id
 215     }
 216 }
 217
 218 pub(crate) struct FunctionDebugContext<'a, 'tcx> {
 219     debug_context: &'a mut DebugContext<'tcx>,
 220     entry_id: UnitEntryId,
 221     symbol: usize,
 222     instance: Instance<'tcx>,
 223     mir: &'tcx mir::Body<'tcx>,
 224 }
 225
 226 impl<'a, 'tcx> FunctionDebugContext<'a, 'tcx> {
 227     pub(crate) fn new(
 228         debug_context: &'a mut DebugContext<'tcx>,
 229         instance: Instance<'tcx>,
 230         func_id: FuncId,
 231         name: &str,
 232     ) -> Self {
 233         let mir = *debug_context.tcx.instance_mir(instance.def);
 234
 235         let (symbol, _) = debug_context.symbols.insert_full(func_id, name.to_string());
 236
 237         // FIXME: add to appropriate scope intead of root
 238         let scope = debug_context.dwarf.unit.root();
 239
 240         let entry_id = debug_context
 241             .dwarf
 242             .unit
 243             .add(scope, gimli::DW_TAG_subprogram);
 244         let entry = debug_context.dwarf.unit.get_mut(entry_id);
 245         let name_id = debug_context.dwarf.strings.add(name);
 246         entry.set(
 247             gimli::DW_AT_linkage_name,
 248             AttributeValue::StringRef(name_id),
 249         );
 250
 251         FunctionDebugContext {
 252             debug_context,
 253             entry_id,
 254             symbol,
 255             instance,
 256             mir,
 257         }
 258     }
 259
 260     fn define_local(&mut self, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 261         let ty = self.debug_context.tcx.subst_and_normalize_erasing_regions(
 262             self.instance.substs,
 263             ty::ParamEnv::reveal_all(),
 264             &ty,
 265         );
 266         let dw_ty = self.debug_context.dwarf_ty(ty);
 267
 268         let var_id = self
 269             .debug_context
 270             .dwarf
 271             .unit
 272             .add(self.entry_id, gimli::DW_TAG_variable);
 273         let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 274
 275         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 276         var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 277
 278         var_id
 279     }
 280
 281     pub(crate) fn define(
 282         &mut self,
 283         context: &Context,
 284         isa: &dyn TargetIsa,
 285         source_info_set: &indexmap::IndexSet<SourceInfo>,
 286         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 287     ) {
 288         let end = self.create_debug_lines(context, isa, source_info_set);
 289
 290         self.debug_context
 291             .unit_range_list
 292             .0
 293             .push(Range::StartLength {
 294                 begin: Address::Symbol {
 295                     symbol: self.symbol,
 296                     addend: 0,
 297                 },
 298                 length: end as u64,
 299             });
 300
 301         // FIXME make it more reliable and implement scopes before re-enabling this.
 302         if false {
 303             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 304
 305             for (local, _local_decl) in self.mir.local_decls.iter_enumerated() {
 306                 let var_id = self.define_local(format!("{:?}", local), &self.mir.local_decls[local].ty);
 307
 308                 let location = place_location(
 309                     self,
 310                     isa,
 311                     context,
 312                     &local_map,
 313                     &value_labels_ranges,
 314                     Place {
 315                         local,
 316                         projection: ty::List::empty(),
 317                     },
 318                 );
 319
 320                 let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 321                 var_entry.set(gimli::DW_AT_location, location);
 322             }
 323         }
 324
 325         // FIXME create locals for all entries in mir.var_debug_info
 326     }
 327 }
 328
 329 fn place_location<'a, 'tcx>(
 330     func_debug_ctx: &mut FunctionDebugContext<'a, 'tcx>,
 331     isa: &dyn TargetIsa,
 332     context: &Context,
 333     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 334     #[allow(rustc::default_hash_types)]
 335     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 336     place: Place<'tcx>,
 337 ) -> AttributeValue {
 338     assert!(place.projection.is_empty()); // FIXME implement them
 339
 340     match local_map[&place.local].inner() {
 341         CPlaceInner::Var(local) => {
 342             let value_label = cranelift_codegen::ir::ValueLabel::from_u32(local.as_u32());
 343             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 344                 let loc_list = LocationList(
 345                     value_loc_ranges
 346                         .iter()
 347                         .map(|value_loc_range| Location::StartEnd {
 348                             begin: Address::Symbol {
 349                                 symbol: func_debug_ctx.symbol,
 350                                 addend: i64::from(value_loc_range.start),
 351                             },
 352                             end: Address::Symbol {
 353                                 symbol: func_debug_ctx.symbol,
 354                                 addend: i64::from(value_loc_range.end),
 355                             },
 356                             data: Expression(
 357                                 translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 358                             ),
 359                         })
 360                         .collect(),
 361                 );
 362                 let loc_list_id = func_debug_ctx.debug_context.dwarf.unit.locations.add(loc_list);
 363
 364                 AttributeValue::LocationListRef(loc_list_id)
 365             } else {
 366                 // FIXME set value labels for unused locals
 367
 368                 AttributeValue::Exprloc(Expression(vec![]))
 369             }
 370         }
 371         CPlaceInner::Addr(_, _) => {
 372             // FIXME implement this (used by arguments and returns)
 373
 374             AttributeValue::Exprloc(Expression(vec![]))
 375
 376             // For PointerBase::Stack:
 377             //AttributeValue::Exprloc(Expression(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap()))
 378         }
 379     }
 380 }
 381
 382 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 383 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Vec<u8>> {
 384     match loc {
 385         ValueLoc::Reg(reg) => {
 386             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 387             assert!(machine_reg <= 32); // FIXME
 388             Some(vec![gimli::constants::DW_OP_reg0.0 + machine_reg as u8])
 389         }
 390         ValueLoc::Stack(ss) => {
 391             if let Some(ss_offset) = stack_slots[ss].offset {
 392                 let endian = gimli::RunTimeEndian::Little;
 393                 let mut writer = write::EndianVec::new(endian);
 394                 writer
 395                     .write_u8(gimli::constants::DW_OP_breg0.0 + X86_64::RBP.0 as u8)
 396                     .expect("bp wr");
 397                 writer.write_sleb128(ss_offset as i64 + 16).expect("ss wr");
 398                 let buf = writer.into_vec();
 399                 return Some(buf);
 400             }
 401             None
 402         }
 403         _ => None,
 404     }
 405 }