compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs

   1 //! Handling of everything related to debuginfo.
   2
   3 mod emit;
   4 mod line_info;
   5 mod object;
   6 mod unwind;
   7
   8 use crate::prelude::*;
   9
  10 use rustc_index::vec::IndexVec;
  11
  12 use cranelift_codegen::entity::EntityRef;
  13 use cranelift_codegen::ir::{Endianness, LabelValueLoc, ValueLabel};
  14 use cranelift_codegen::isa::TargetIsa;
  15 use cranelift_codegen::ValueLocRange;
  16
  17 use gimli::write::{
  18     Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
  19     LocationList, Range, RangeList, UnitEntryId,
  20 };
  21 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
  22
  23 pub(crate) use emit::{DebugReloc, DebugRelocName};
  24 pub(crate) use unwind::UnwindContext;
  25
  26 pub(crate) struct DebugContext<'tcx> {
  27     tcx: TyCtxt<'tcx>,
  28
  29     endian: RunTimeEndian,
  30
  31     dwarf: DwarfUnit,
  32     unit_range_list: RangeList,
  33
  34     types: FxHashMap<Ty<'tcx>, UnitEntryId>,
  35 }
  36
  37 impl<'tcx> DebugContext<'tcx> {
  38     pub(crate) fn new(tcx: TyCtxt<'tcx>, isa: &dyn TargetIsa) -> Self {
  39         let encoding = Encoding {
  40             format: Format::Dwarf32,
  41             // FIXME this should be configurable
  42             // macOS doesn't seem to support DWARF > 3
  43             // 5 version is required for md5 file hash
  44             version: if tcx.sess.target.is_like_osx {
  45                 3
  46             } else {
  47                 // FIXME change to version 5 once the gdb and lldb shipping with the latest debian
  48                 // support it.
  49                 4
  50             },
  51             address_size: isa.frontend_config().pointer_bytes(),
  52         };
  53
  54         let endian = match isa.endianness() {
  55             Endianness::Little => RunTimeEndian::Little,
  56             Endianness::Big => RunTimeEndian::Big,
  57         };
  58
  59         let mut dwarf = DwarfUnit::new(encoding);
  60
  61         let producer = format!(
  62             "cg_clif (rustc {}, cranelift {})",
  63             rustc_interface::util::version_str().unwrap_or("unknown version"),
  64             cranelift_codegen::VERSION,
  65         );
  66         let comp_dir = tcx
  67             .sess
  68             .opts
  69             .working_dir
  70             .to_string_lossy(FileNameDisplayPreference::Remapped)
  71             .into_owned();
  72         let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
  73             Some(path) => {
  74                 let name = path.to_string_lossy().into_owned();
  75                 (name, None)
  76             }
  77             None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
  78         };
  79
  80         let mut line_program = LineProgram::new(
  81             encoding,
  82             LineEncoding::default(),
  83             LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
  84             LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
  85             file_info,
  86         );
  87         line_program.file_has_md5 = file_info.is_some();
  88
  89         dwarf.unit.line_program = line_program;
  90
  91         {
  92             let name = dwarf.strings.add(name);
  93             let comp_dir = dwarf.strings.add(comp_dir);
  94
  95             let root = dwarf.unit.root();
  96             let root = dwarf.unit.get_mut(root);
  97             root.set(gimli::DW_AT_producer, AttributeValue::StringRef(dwarf.strings.add(producer)));
  98             root.set(gimli::DW_AT_language, AttributeValue::Language(gimli::DW_LANG_Rust));
  99             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 100             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 101             root.set(gimli::DW_AT_low_pc, AttributeValue::Address(Address::Constant(0)));
 102         }
 103
 104         DebugContext {
 105             tcx,
 106
 107             endian,
 108
 109             dwarf,
 110             unit_range_list: RangeList(Vec::new()),
 111
 112             types: FxHashMap::default(),
 113         }
 114     }
 115
 116     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 117         if let Some(type_id) = self.types.get(&ty) {
 118             return *type_id;
 119         }
 120
 121         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 122
 123         let primitive = |dwarf: &mut DwarfUnit, ate| {
 124             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 125             let type_entry = dwarf.unit.get_mut(type_id);
 126             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 127             type_id
 128         };
 129
 130         let name = format!("{}", ty);
 131         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 132
 133         let type_id = match ty.kind() {
 134             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 135             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 136             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 137             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 138             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 139             ty::Ref(_, pointee_ty, _mutbl)
 140             | ty::RawPtr(ty::TypeAndMut { ty: pointee_ty, mutbl: _mutbl }) => {
 141                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 142
 143                 // Ensure that type is inserted before recursing to avoid duplicates
 144                 self.types.insert(ty, type_id);
 145
 146                 let pointee = self.dwarf_ty(*pointee_ty);
 147
 148                 let type_entry = self.dwarf.unit.get_mut(type_id);
 149
 150                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 151                 type_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(pointee));
 152
 153                 type_id
 154             }
 155             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 156                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 157
 158                 // Ensure that type is inserted before recursing to avoid duplicates
 159                 self.types.insert(ty, type_id);
 160
 161                 let variant = adt_def.non_enum_variant();
 162
 163                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 164                     let field_offset = layout.fields.offset(field_idx);
 165                     let field_layout = layout.field(
 166                         &layout::LayoutCx { tcx: self.tcx, param_env: ParamEnv::reveal_all() },
 167                         field_idx,
 168                     );
 169
 170                     let field_type = self.dwarf_ty(field_layout.ty);
 171
 172                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 173                     let field_entry = self.dwarf.unit.get_mut(field_id);
 174
 175                     field_entry.set(
 176                         gimli::DW_AT_name,
 177                         AttributeValue::String(field_def.name.as_str().to_string().into_bytes()),
 178                     );
 179                     field_entry.set(
 180                         gimli::DW_AT_data_member_location,
 181                         AttributeValue::Udata(field_offset.bytes()),
 182                     );
 183                     field_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(field_type));
 184                 }
 185
 186                 type_id
 187             }
 188             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 189         };
 190
 191         let type_entry = self.dwarf.unit.get_mut(type_id);
 192
 193         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 194         type_entry.set(gimli::DW_AT_byte_size, AttributeValue::Udata(layout.size.bytes()));
 195
 196         self.types.insert(ty, type_id);
 197
 198         type_id
 199     }
 200
 201     fn define_local(&mut self, scope: UnitEntryId, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 202         let dw_ty = self.dwarf_ty(ty);
 203
 204         let var_id = self.dwarf.unit.add(scope, gimli::DW_TAG_variable);
 205         let var_entry = self.dwarf.unit.get_mut(var_id);
 206
 207         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 208         var_entry.set(gimli::DW_AT_type, AttributeValue::UnitRef(dw_ty));
 209
 210         var_id
 211     }
 212
 213     pub(crate) fn define_function(
 214         &mut self,
 215         instance: Instance<'tcx>,
 216         func_id: FuncId,
 217         name: &str,
 218         isa: &dyn TargetIsa,
 219         context: &Context,
 220         source_info_set: &indexmap::IndexSet<SourceInfo>,
 221         local_map: IndexVec<mir::Local, CPlace<'tcx>>,
 222     ) {
 223         let symbol = func_id.as_u32() as usize;
 224         let mir = self.tcx.instance_mir(instance.def);
 225
 226         // FIXME: add to appropriate scope instead of root
 227         let scope = self.dwarf.unit.root();
 228
 229         let entry_id = self.dwarf.unit.add(scope, gimli::DW_TAG_subprogram);
 230         let entry = self.dwarf.unit.get_mut(entry_id);
 231         let name_id = self.dwarf.strings.add(name);
 232         // Gdb requires DW_AT_name. Otherwise the DW_TAG_subprogram is skipped.
 233         entry.set(gimli::DW_AT_name, AttributeValue::StringRef(name_id));
 234         entry.set(gimli::DW_AT_linkage_name, AttributeValue::StringRef(name_id));
 235
 236         let end = self.create_debug_lines(symbol, entry_id, context, mir.span, source_info_set);
 237
 238         self.unit_range_list.0.push(Range::StartLength {
 239             begin: Address::Symbol { symbol, addend: 0 },
 240             length: u64::from(end),
 241         });
 242
 243         let func_entry = self.dwarf.unit.get_mut(entry_id);
 244         // Gdb requires both DW_AT_low_pc and DW_AT_high_pc. Otherwise the DW_TAG_subprogram is skipped.
 245         func_entry.set(
 246             gimli::DW_AT_low_pc,
 247             AttributeValue::Address(Address::Symbol { symbol, addend: 0 }),
 248         );
 249         // Using Udata for DW_AT_high_pc requires at least DWARF4
 250         func_entry.set(gimli::DW_AT_high_pc, AttributeValue::Udata(u64::from(end)));
 251
 252         // FIXME make it more reliable and implement scopes before re-enabling this.
 253         if false {
 254             let value_labels_ranges = std::collections::HashMap::new(); // FIXME
 255
 256             for (local, _local_decl) in mir.local_decls.iter_enumerated() {
 257                 let ty = self.tcx.subst_and_normalize_erasing_regions(
 258                     instance.substs,
 259                     ty::ParamEnv::reveal_all(),
 260                     mir.local_decls[local].ty,
 261                 );
 262                 let var_id = self.define_local(entry_id, format!("{:?}", local), ty);
 263
 264                 let location = place_location(
 265                     self,
 266                     isa,
 267                     symbol,
 268                     &local_map,
 269                     &value_labels_ranges,
 270                     Place { local, projection: ty::List::empty() },
 271                 );
 272
 273                 let var_entry = self.dwarf.unit.get_mut(var_id);
 274                 var_entry.set(gimli::DW_AT_location, location);
 275             }
 276         }
 277
 278         // FIXME create locals for all entries in mir.var_debug_info
 279     }
 280 }
 281
 282 fn place_location<'tcx>(
 283     debug_context: &mut DebugContext<'tcx>,
 284     isa: &dyn TargetIsa,
 285     symbol: usize,
 286     local_map: &IndexVec<mir::Local, CPlace<'tcx>>,
 287     #[allow(rustc::default_hash_types)] value_labels_ranges: &std::collections::HashMap<
 288         ValueLabel,
 289         Vec<ValueLocRange>,
 290     >,
 291     place: Place<'tcx>,
 292 ) -> AttributeValue {
 293     assert!(place.projection.is_empty()); // FIXME implement them
 294
 295     match local_map[place.local].inner() {
 296         CPlaceInner::Var(_local, var) => {
 297             let value_label = cranelift_codegen::ir::ValueLabel::new(var.index());
 298             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 299                 let loc_list = LocationList(
 300                     value_loc_ranges
 301                         .iter()
 302                         .map(|value_loc_range| Location::StartEnd {
 303                             begin: Address::Symbol {
 304                                 symbol,
 305                                 addend: i64::from(value_loc_range.start),
 306                             },
 307                             end: Address::Symbol { symbol, addend: i64::from(value_loc_range.end) },
 308                             data: translate_loc(isa, value_loc_range.loc).unwrap(),
 309                         })
 310                         .collect(),
 311                 );
 312                 let loc_list_id = debug_context.dwarf.unit.locations.add(loc_list);
 313
 314                 AttributeValue::LocationListRef(loc_list_id)
 315             } else {
 316                 // FIXME set value labels for unused locals
 317
 318                 AttributeValue::Exprloc(Expression::new())
 319             }
 320         }
 321         CPlaceInner::VarPair(_, _, _) => {
 322             // FIXME implement this
 323
 324             AttributeValue::Exprloc(Expression::new())
 325         }
 326         CPlaceInner::VarLane(_, _, _) => {
 327             // FIXME implement this
 328
 329             AttributeValue::Exprloc(Expression::new())
 330         }
 331         CPlaceInner::Addr(_, _) => {
 332             // FIXME implement this (used by arguments and returns)
 333
 334             AttributeValue::Exprloc(Expression::new())
 335
 336             // For PointerBase::Stack:
 337             //AttributeValue::Exprloc(translate_loc(ValueLoc::Stack(*stack_slot)).unwrap())
 338         }
 339     }
 340 }
 341
 342 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 343 fn translate_loc(isa: &dyn TargetIsa, loc: LabelValueLoc) -> Option<Expression> {
 344     match loc {
 345         LabelValueLoc::Reg(reg) => {
 346             let machine_reg = isa.map_regalloc_reg_to_dwarf(reg).unwrap();
 347             let mut expr = Expression::new();
 348             expr.op_reg(gimli::Register(machine_reg));
 349             Some(expr)
 350         }
 351         LabelValueLoc::SPOffset(offset) => {
 352             let mut expr = Expression::new();
 353             expr.op_breg(X86_64::RSP, offset);
 354             Some(expr)
 355         }
 356     }
 357 }