src/debuginfo/mod.rs

   1 mod emit;
   2 mod line_info;
   3
   4 use std::convert::TryFrom;
   5
   6 use crate::prelude::*;
   7
   8 use rustc_span::FileName;
   9
  10 use cranelift_codegen::ir::{StackSlots, ValueLabel, ValueLoc};
  11 use cranelift_codegen::isa::TargetIsa;
  12 use cranelift_codegen::ValueLocRange;
  13
  14 use gimli::write::{
  15     self, Address, AttributeValue, DwarfUnit, Expression, LineProgram, LineString, Location,
  16     LocationList, Range, RangeList, UnitEntryId, Writer, FileInfo,
  17 };
  18 use gimli::{Encoding, Format, LineEncoding, RunTimeEndian, X86_64};
  19
  20 pub(crate) use emit::{DebugReloc, DebugRelocName};
  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     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, file_hash) = 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                     .and_then(|f| line_info::FileHash::try_from(f.src_hash).ok());
  71                 (name, hash)
  72             },
  73             None => (tcx.crate_name(LOCAL_CRATE).to_string(), None),
  74         };
  75
  76         let mut line_program = LineProgram::new(
  77             encoding,
  78             LineEncoding::default(),
  79             LineString::new(comp_dir.as_bytes(), encoding, &mut dwarf.line_strings),
  80             LineString::new(name.as_bytes(), encoding, &mut dwarf.line_strings),
  81             Some(FileInfo {
  82                 timestamp: 0,
  83                 size: 0,
  84                 md5: file_hash.unwrap_or_default().inner(),
  85             }),
  86         );
  87         line_program.file_has_md5 = file_hash.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(
  98                 gimli::DW_AT_producer,
  99                 AttributeValue::StringRef(dwarf.strings.add(producer)),
 100             );
 101             root.set(
 102                 gimli::DW_AT_language,
 103                 AttributeValue::Language(gimli::DW_LANG_Rust),
 104             );
 105             root.set(gimli::DW_AT_name, AttributeValue::StringRef(name));
 106             root.set(gimli::DW_AT_comp_dir, AttributeValue::StringRef(comp_dir));
 107             root.set(
 108                 gimli::DW_AT_low_pc,
 109                 AttributeValue::Address(Address::Constant(0)),
 110             );
 111         }
 112
 113         DebugContext {
 114             tcx,
 115
 116             endian: target_endian(tcx),
 117             symbols: indexmap::IndexMap::new(),
 118
 119             dwarf,
 120             unit_range_list: RangeList(Vec::new()),
 121
 122             types: FxHashMap::default(),
 123         }
 124     }
 125
 126     fn dwarf_ty(&mut self, ty: Ty<'tcx>) -> UnitEntryId {
 127         if let Some(type_id) = self.types.get(ty) {
 128             return *type_id;
 129         }
 130
 131         let new_entry = |dwarf: &mut DwarfUnit, tag| dwarf.unit.add(dwarf.unit.root(), tag);
 132
 133         let primitive = |dwarf: &mut DwarfUnit, ate| {
 134             let type_id = new_entry(dwarf, gimli::DW_TAG_base_type);
 135             let type_entry = dwarf.unit.get_mut(type_id);
 136             type_entry.set(gimli::DW_AT_encoding, AttributeValue::Encoding(ate));
 137             type_id
 138         };
 139
 140         let name = format!("{}", ty);
 141         let layout = self.tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap();
 142
 143         let type_id = match ty.kind {
 144             ty::Bool => primitive(&mut self.dwarf, gimli::DW_ATE_boolean),
 145             ty::Char => primitive(&mut self.dwarf, gimli::DW_ATE_UTF),
 146             ty::Uint(_) => primitive(&mut self.dwarf, gimli::DW_ATE_unsigned),
 147             ty::Int(_) => primitive(&mut self.dwarf, gimli::DW_ATE_signed),
 148             ty::Float(_) => primitive(&mut self.dwarf, gimli::DW_ATE_float),
 149             ty::Ref(_, pointee_ty, _mutbl)
 150             | ty::RawPtr(ty::TypeAndMut {
 151                 ty: pointee_ty,
 152                 mutbl: _mutbl,
 153             }) => {
 154                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_pointer_type);
 155
 156                 // Ensure that type is inserted before recursing to avoid duplicates
 157                 self.types.insert(ty, type_id);
 158
 159                 let pointee = self.dwarf_ty(pointee_ty);
 160
 161                 let type_entry = self.dwarf.unit.get_mut(type_id);
 162
 163                 //type_entry.set(gimli::DW_AT_mutable, AttributeValue::Flag(mutbl == rustc_hir::Mutability::Mut));
 164                 type_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(pointee));
 165
 166                 type_id
 167             }
 168             ty::Adt(adt_def, _substs) if adt_def.is_struct() && !layout.is_unsized() => {
 169                 let type_id = new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type);
 170
 171                 // Ensure that type is inserted before recursing to avoid duplicates
 172                 self.types.insert(ty, type_id);
 173
 174                 let variant = adt_def.non_enum_variant();
 175
 176                 for (field_idx, field_def) in variant.fields.iter().enumerate() {
 177                     let field_offset = layout.fields.offset(field_idx);
 178                     let field_layout = layout.field(&layout::LayoutCx {
 179                         tcx: self.tcx,
 180                         param_env: ParamEnv::reveal_all(),
 181                     }, field_idx).unwrap();
 182
 183                     let field_type = self.dwarf_ty(field_layout.ty);
 184
 185                     let field_id = self.dwarf.unit.add(type_id, gimli::DW_TAG_member);
 186                     let field_entry = self.dwarf.unit.get_mut(field_id);
 187
 188                     field_entry.set(gimli::DW_AT_name, AttributeValue::String(field_def.ident.as_str().to_string().into_bytes()));
 189                     field_entry.set(gimli::DW_AT_data_member_location, AttributeValue::Udata(field_offset.bytes()));
 190                     field_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(field_type));
 191                 }
 192
 193                 type_id
 194             }
 195             _ => new_entry(&mut self.dwarf, gimli::DW_TAG_structure_type),
 196         };
 197
 198         let type_entry = self.dwarf.unit.get_mut(type_id);
 199
 200         type_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 201         type_entry.set(
 202             gimli::DW_AT_byte_size,
 203             AttributeValue::Udata(layout.size.bytes()),
 204         );
 205
 206         self.types.insert(ty, type_id);
 207
 208         type_id
 209     }
 210 }
 211
 212 pub(crate) struct FunctionDebugContext<'a, 'tcx> {
 213     debug_context: &'a mut DebugContext<'tcx>,
 214     entry_id: UnitEntryId,
 215     symbol: usize,
 216     instance: Instance<'tcx>,
 217     mir: &'tcx mir::Body<'tcx>,
 218 }
 219
 220 impl<'a, 'tcx> FunctionDebugContext<'a, 'tcx> {
 221     pub(crate) fn new(
 222         debug_context: &'a mut DebugContext<'tcx>,
 223         instance: Instance<'tcx>,
 224         func_id: FuncId,
 225         name: &str,
 226     ) -> Self {
 227         let mir = *debug_context.tcx.instance_mir(instance.def);
 228
 229         let (symbol, _) = debug_context.symbols.insert_full(func_id, name.to_string());
 230
 231         // FIXME: add to appropriate scope intead of root
 232         let scope = debug_context.dwarf.unit.root();
 233
 234         let entry_id = debug_context
 235             .dwarf
 236             .unit
 237             .add(scope, gimli::DW_TAG_subprogram);
 238         let entry = debug_context.dwarf.unit.get_mut(entry_id);
 239         let name_id = debug_context.dwarf.strings.add(name);
 240         entry.set(
 241             gimli::DW_AT_linkage_name,
 242             AttributeValue::StringRef(name_id),
 243         );
 244
 245         FunctionDebugContext {
 246             debug_context,
 247             entry_id,
 248             symbol,
 249             instance,
 250             mir,
 251         }
 252     }
 253
 254     fn define_local(&mut self, name: String, ty: Ty<'tcx>) -> UnitEntryId {
 255         let ty = self.debug_context.tcx.subst_and_normalize_erasing_regions(
 256             self.instance.substs,
 257             ty::ParamEnv::reveal_all(),
 258             &ty,
 259         );
 260         let dw_ty = self.debug_context.dwarf_ty(ty);
 261
 262         let var_id = self
 263             .debug_context
 264             .dwarf
 265             .unit
 266             .add(self.entry_id, gimli::DW_TAG_variable);
 267         let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 268
 269         var_entry.set(gimli::DW_AT_name, AttributeValue::String(name.into_bytes()));
 270         var_entry.set(gimli::DW_AT_type, AttributeValue::ThisUnitEntryRef(dw_ty));
 271
 272         var_id
 273     }
 274
 275     pub(crate) fn define(
 276         &mut self,
 277         context: &Context,
 278         isa: &dyn TargetIsa,
 279         source_info_set: &indexmap::IndexSet<SourceInfo>,
 280         local_map: FxHashMap<mir::Local, CPlace<'tcx>>,
 281     ) {
 282         let end = self.create_debug_lines(context, isa, source_info_set);
 283
 284         self.debug_context
 285             .unit_range_list
 286             .0
 287             .push(Range::StartLength {
 288                 begin: Address::Symbol {
 289                     symbol: self.symbol,
 290                     addend: 0,
 291                 },
 292                 length: end as u64,
 293             });
 294
 295         // FIXME make it more reliable and implement scopes before re-enabling this.
 296         if false {
 297             let value_labels_ranges = context.build_value_labels_ranges(isa).unwrap();
 298
 299             for (local, _local_decl) in self.mir.local_decls.iter_enumerated() {
 300                 let var_id = self.define_local(format!("{:?}", local), &self.mir.local_decls[local].ty);
 301
 302                 let location = place_location(
 303                     self,
 304                     isa,
 305                     context,
 306                     &local_map,
 307                     &value_labels_ranges,
 308                     Place {
 309                         local,
 310                         projection: ty::List::empty(),
 311                     },
 312                 );
 313
 314                 let var_entry = self.debug_context.dwarf.unit.get_mut(var_id);
 315                 var_entry.set(gimli::DW_AT_location, location);
 316             }
 317         }
 318
 319         // FIXME create locals for all entries in mir.var_debug_info
 320     }
 321 }
 322
 323 fn place_location<'a, 'tcx>(
 324     func_debug_ctx: &mut FunctionDebugContext<'a, 'tcx>,
 325     isa: &dyn TargetIsa,
 326     context: &Context,
 327     local_map: &FxHashMap<mir::Local, CPlace<'tcx>>,
 328     #[allow(rustc::default_hash_types)]
 329     value_labels_ranges: &std::collections::HashMap<ValueLabel, Vec<ValueLocRange>>,
 330     place: Place<'tcx>,
 331 ) -> AttributeValue {
 332     assert!(place.projection.is_empty()); // FIXME implement them
 333
 334     match local_map[&place.local].inner() {
 335         CPlaceInner::Var(local) => {
 336             let value_label = cranelift_codegen::ir::ValueLabel::from_u32(local.as_u32());
 337             if let Some(value_loc_ranges) = value_labels_ranges.get(&value_label) {
 338                 let loc_list = LocationList(
 339                     value_loc_ranges
 340                         .iter()
 341                         .map(|value_loc_range| Location::StartEnd {
 342                             begin: Address::Symbol {
 343                                 symbol: func_debug_ctx.symbol,
 344                                 addend: i64::from(value_loc_range.start),
 345                             },
 346                             end: Address::Symbol {
 347                                 symbol: func_debug_ctx.symbol,
 348                                 addend: i64::from(value_loc_range.end),
 349                             },
 350                             data: Expression(
 351                                 translate_loc(isa, value_loc_range.loc, &context.func.stack_slots).unwrap(),
 352                             ),
 353                         })
 354                         .collect(),
 355                 );
 356                 let loc_list_id = func_debug_ctx.debug_context.dwarf.unit.locations.add(loc_list);
 357
 358                 AttributeValue::LocationListRef(loc_list_id)
 359             } else {
 360                 // FIXME set value labels for unused locals
 361
 362                 AttributeValue::Exprloc(Expression(vec![]))
 363             }
 364         }
 365         CPlaceInner::Addr(_, _) => {
 366             // FIXME implement this (used by arguments and returns)
 367
 368             AttributeValue::Exprloc(Expression(vec![]))
 369
 370             // For PointerBase::Stack:
 371             //AttributeValue::Exprloc(Expression(translate_loc(ValueLoc::Stack(*stack_slot), &context.func.stack_slots).unwrap()))
 372         }
 373     }
 374 }
 375
 376 // Adapted from https://github.com/CraneStation/wasmtime/blob/5a1845b4caf7a5dba8eda1fef05213a532ed4259/crates/debug/src/transform/expression.rs#L59-L137
 377 fn translate_loc(isa: &dyn TargetIsa, loc: ValueLoc, stack_slots: &StackSlots) -> Option<Vec<u8>> {
 378     match loc {
 379         ValueLoc::Reg(reg) => {
 380             let machine_reg = isa.map_dwarf_register(reg).unwrap();
 381             assert!(machine_reg <= 32); // FIXME
 382             Some(vec![gimli::constants::DW_OP_reg0.0 + machine_reg as u8])
 383         }
 384         ValueLoc::Stack(ss) => {
 385             if let Some(ss_offset) = stack_slots[ss].offset {
 386                 let endian = gimli::RunTimeEndian::Little;
 387                 let mut writer = write::EndianVec::new(endian);
 388                 writer
 389                     .write_u8(gimli::constants::DW_OP_breg0.0 + X86_64::RBP.0 as u8)
 390                     .expect("bp wr");
 391                 writer.write_sleb128(ss_offset as i64 + 16).expect("ss wr");
 392                 let buf = writer.into_vec();
 393                 return Some(buf);
 394             }
 395             None
 396         }
 397         _ => None,
 398     }
 399 }