lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp

   1 #include "UdtRecordCompleter.h"
   2
   3 #include "PdbAstBuilder.h"
   4 #include "PdbIndex.h"
   5 #include "PdbSymUid.h"
   6 #include "PdbUtil.h"
   7
   8 #include "Plugins/ExpressionParser/Clang/ClangASTImporter.h"
   9 #include "Plugins/ExpressionParser/Clang/ClangASTMetadata.h"
  10 #include "Plugins/ExpressionParser/Clang/ClangUtil.h"
  11 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
  12 #include "SymbolFileNativePDB.h"
  13 #include "lldb/Core/Address.h"
  14 #include "lldb/Symbol/Type.h"
  15 #include "lldb/Utility/LLDBAssert.h"
  16 #include "lldb/Utility/LLDBLog.h"
  17 #include "lldb/lldb-enumerations.h"
  18 #include "lldb/lldb-forward.h"
  19
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
  22 #include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
  23 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
  24 #include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
  25 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
  26 #include "llvm/DebugInfo/PDB/PDBTypes.h"
  27 #include <optional>
  28
  29 using namespace llvm::codeview;
  30 using namespace llvm::pdb;
  31 using namespace lldb;
  32 using namespace lldb_private;
  33 using namespace lldb_private::npdb;
  34
  35 using Error = llvm::Error;
  36
  37 UdtRecordCompleter::UdtRecordCompleter(
  38     PdbTypeSymId id, CompilerType &derived_ct, clang::TagDecl &tag_decl,
  39     PdbAstBuilder &ast_builder, PdbIndex &index,
  40     llvm::DenseMap<clang::Decl *, DeclStatus> &decl_to_status,
  41     llvm::DenseMap<lldb::opaque_compiler_type_t,
  42                    llvm::SmallSet<std::pair<llvm::StringRef, CompilerType>, 8>>
  43         &cxx_record_map)
  44     : m_id(id), m_derived_ct(derived_ct), m_tag_decl(tag_decl),
  45       m_ast_builder(ast_builder), m_index(index),
  46       m_decl_to_status(decl_to_status), m_cxx_record_map(cxx_record_map) {
  47   CVType cvt = m_index.tpi().getType(m_id.index);
  48   switch (cvt.kind()) {
  49   case LF_ENUM:
  50     llvm::cantFail(TypeDeserializer::deserializeAs<EnumRecord>(cvt, m_cvr.er));
  51     break;
  52   case LF_UNION:
  53     llvm::cantFail(TypeDeserializer::deserializeAs<UnionRecord>(cvt, m_cvr.ur));
  54     m_layout.bit_size = m_cvr.ur.getSize() * 8;
  55     m_record.record.kind = Member::Union;
  56     break;
  57   case LF_CLASS:
  58   case LF_STRUCTURE:
  59     llvm::cantFail(TypeDeserializer::deserializeAs<ClassRecord>(cvt, m_cvr.cr));
  60     m_layout.bit_size = m_cvr.cr.getSize() * 8;
  61     m_record.record.kind = Member::Struct;
  62     break;
  63   default:
  64     llvm_unreachable("unreachable!");
  65   }
  66 }
  67
  68 clang::QualType UdtRecordCompleter::AddBaseClassForTypeIndex(
  69     llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access,
  70     std::optional<uint64_t> vtable_idx) {
  71   PdbTypeSymId type_id(ti);
  72   clang::QualType qt = m_ast_builder.GetOrCreateType(type_id);
  73
  74   CVType udt_cvt = m_index.tpi().getType(ti);
  75
  76   std::unique_ptr<clang::CXXBaseSpecifier> base_spec =
  77       m_ast_builder.clang().CreateBaseClassSpecifier(
  78           qt.getAsOpaquePtr(), TranslateMemberAccess(access),
  79           vtable_idx.has_value(), udt_cvt.kind() == LF_CLASS);
  80   if (!base_spec)
  81     return {};
  82
  83   m_bases.push_back(
  84       std::make_pair(vtable_idx.value_or(0), std::move(base_spec)));
  85
  86   return qt;
  87 }
  88
  89 void UdtRecordCompleter::AddMethod(llvm::StringRef name, TypeIndex type_idx,
  90                                    MemberAccess access, MethodOptions options,
  91                                    MemberAttributes attrs) {
  92   clang::QualType method_qt =
  93       m_ast_builder.GetOrCreateType(PdbTypeSymId(type_idx));
  94   if (method_qt.isNull())
  95     return;
  96   CompilerType method_ct = m_ast_builder.ToCompilerType(method_qt);
  97   TypeSystemClang::RequireCompleteType(method_ct);
  98   lldb::opaque_compiler_type_t derived_opaque_ty =
  99       m_derived_ct.GetOpaqueQualType();
 100   auto iter = m_cxx_record_map.find(derived_opaque_ty);
 101   if (iter != m_cxx_record_map.end()) {
 102     if (iter->getSecond().contains({name, method_ct})) {
 103       return;
 104     }
 105   }
 106
 107   lldb::AccessType access_type = TranslateMemberAccess(access);
 108   bool is_artificial = (options & MethodOptions::CompilerGenerated) ==
 109                        MethodOptions::CompilerGenerated;
 110   m_ast_builder.clang().AddMethodToCXXRecordType(
 111       derived_opaque_ty, name.data(), nullptr, method_ct,
 112       access_type, attrs.isVirtual(), attrs.isStatic(), false, false, false,
 113       is_artificial);
 114
 115   m_cxx_record_map[derived_opaque_ty].insert({name, method_ct});
 116 }
 117
 118 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 119                                            BaseClassRecord &base) {
 120   clang::QualType base_qt =
 121       AddBaseClassForTypeIndex(base.Type, base.getAccess());
 122
 123   if (base_qt.isNull())
 124     return llvm::Error::success();
 125   auto decl =
 126       m_ast_builder.clang().GetAsCXXRecordDecl(base_qt.getAsOpaquePtr());
 127   lldbassert(decl);
 128
 129   auto offset = clang::CharUnits::fromQuantity(base.getBaseOffset());
 130   m_layout.base_offsets.insert(std::make_pair(decl, offset));
 131
 132   return llvm::Error::success();
 133 }
 134
 135 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 136                                            VirtualBaseClassRecord &base) {
 137   AddBaseClassForTypeIndex(base.BaseType, base.getAccess(), base.VTableIndex);
 138
 139   return Error::success();
 140 }
 141
 142 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 143                                            ListContinuationRecord &cont) {
 144   return Error::success();
 145 }
 146
 147 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 148                                            VFPtrRecord &vfptr) {
 149   return Error::success();
 150 }
 151
 152 Error UdtRecordCompleter::visitKnownMember(
 153     CVMemberRecord &cvr, StaticDataMemberRecord &static_data_member) {
 154   clang::QualType member_type =
 155       m_ast_builder.GetOrCreateType(PdbTypeSymId(static_data_member.Type));
 156   if (member_type.isNull())
 157     return llvm::Error::success();
 158
 159   CompilerType member_ct = m_ast_builder.ToCompilerType(member_type);
 160
 161   lldb::AccessType access =
 162       TranslateMemberAccess(static_data_member.getAccess());
 163   auto decl = TypeSystemClang::AddVariableToRecordType(
 164       m_derived_ct, static_data_member.Name, member_ct, access);
 165
 166   // Static constant members may be a const[expr] declaration.
 167   // Query the symbol's value as the variable initializer if valid.
 168   if (member_ct.IsConst() && member_ct.IsCompleteType()) {
 169     std::string qual_name = decl->getQualifiedNameAsString();
 170
 171     auto results =
 172         m_index.globals().findRecordsByName(qual_name, m_index.symrecords());
 173
 174     for (const auto &result : results) {
 175       if (result.second.kind() == SymbolKind::S_CONSTANT) {
 176         ConstantSym constant(SymbolRecordKind::ConstantSym);
 177         cantFail(SymbolDeserializer::deserializeAs<ConstantSym>(result.second,
 178                                                                 constant));
 179
 180         clang::QualType qual_type = decl->getType();
 181         unsigned type_width = decl->getASTContext().getIntWidth(qual_type);
 182         unsigned constant_width = constant.Value.getBitWidth();
 183
 184         if (qual_type->isIntegralOrEnumerationType()) {
 185           if (type_width >= constant_width) {
 186             TypeSystemClang::SetIntegerInitializerForVariable(
 187                 decl, constant.Value.extOrTrunc(type_width));
 188           } else {
 189             LLDB_LOG(GetLog(LLDBLog::AST),
 190                      "Class '{0}' has a member '{1}' of type '{2}' ({3} bits) "
 191                      "which resolves to a wider constant value ({4} bits). "
 192                      "Ignoring constant.",
 193                      m_derived_ct.GetTypeName(), static_data_member.Name,
 194                      member_ct.GetTypeName(), type_width, constant_width);
 195           }
 196         } else {
 197           lldb::BasicType basic_type_enum = member_ct.GetBasicTypeEnumeration();
 198           switch (basic_type_enum) {
 199           case lldb::eBasicTypeFloat:
 200           case lldb::eBasicTypeDouble:
 201           case lldb::eBasicTypeLongDouble:
 202             if (type_width == constant_width) {
 203               TypeSystemClang::SetFloatingInitializerForVariable(
 204                   decl, basic_type_enum == lldb::eBasicTypeFloat
 205                             ? llvm::APFloat(constant.Value.bitsToFloat())
 206                             : llvm::APFloat(constant.Value.bitsToDouble()));
 207               decl->setConstexpr(true);
 208             } else {
 209               LLDB_LOG(
 210                   GetLog(LLDBLog::AST),
 211                   "Class '{0}' has a member '{1}' of type '{2}' ({3} bits) "
 212                   "which resolves to a constant value of mismatched width "
 213                   "({4} bits). Ignoring constant.",
 214                   m_derived_ct.GetTypeName(), static_data_member.Name,
 215                   member_ct.GetTypeName(), type_width, constant_width);
 216             }
 217             break;
 218           default:
 219             break;
 220           }
 221         }
 222         break;
 223       }
 224     }
 225   }
 226
 227   // FIXME: Add a PdbSymUid namespace for field list members and update
 228   // the m_uid_to_decl map with this decl.
 229   return Error::success();
 230 }
 231
 232 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 233                                            NestedTypeRecord &nested) {
 234   return Error::success();
 235 }
 236
 237 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 238                                            DataMemberRecord &data_member) {
 239
 240   uint64_t offset = data_member.FieldOffset * 8;
 241   uint32_t bitfield_width = 0;
 242
 243   TypeIndex ti(data_member.Type);
 244   if (!ti.isSimple()) {
 245     CVType cvt = m_index.tpi().getType(ti);
 246     if (cvt.kind() == LF_BITFIELD) {
 247       BitFieldRecord bfr;
 248       llvm::cantFail(TypeDeserializer::deserializeAs<BitFieldRecord>(cvt, bfr));
 249       offset += bfr.BitOffset;
 250       bitfield_width = bfr.BitSize;
 251       ti = bfr.Type;
 252     }
 253   }
 254
 255   clang::QualType member_qt = m_ast_builder.GetOrCreateType(PdbTypeSymId(ti));
 256   if (member_qt.isNull())
 257     return Error::success();
 258   TypeSystemClang::RequireCompleteType(m_ast_builder.ToCompilerType(member_qt));
 259   lldb::AccessType access = TranslateMemberAccess(data_member.getAccess());
 260   size_t field_size =
 261       bitfield_width ? bitfield_width : GetSizeOfType(ti, m_index.tpi()) * 8;
 262   if (field_size == 0)
 263     return Error::success();
 264   m_record.CollectMember(data_member.Name, offset, field_size, member_qt, access,
 265                 bitfield_width);
 266   return Error::success();
 267 }
 268
 269 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 270                                            OneMethodRecord &one_method) {
 271   AddMethod(one_method.Name, one_method.Type, one_method.getAccess(),
 272             one_method.getOptions(), one_method.Attrs);
 273
 274   return Error::success();
 275 }
 276
 277 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 278                                            OverloadedMethodRecord &overloaded) {
 279   TypeIndex method_list_idx = overloaded.MethodList;
 280
 281   CVType method_list_type = m_index.tpi().getType(method_list_idx);
 282   assert(method_list_type.kind() == LF_METHODLIST);
 283
 284   MethodOverloadListRecord method_list;
 285   llvm::cantFail(TypeDeserializer::deserializeAs<MethodOverloadListRecord>(
 286       method_list_type, method_list));
 287
 288   for (const OneMethodRecord &method : method_list.Methods)
 289     AddMethod(overloaded.Name, method.Type, method.getAccess(),
 290               method.getOptions(), method.Attrs);
 291
 292   return Error::success();
 293 }
 294
 295 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 296                                            EnumeratorRecord &enumerator) {
 297   Declaration decl;
 298   llvm::StringRef name = DropNameScope(enumerator.getName());
 299
 300   m_ast_builder.clang().AddEnumerationValueToEnumerationType(
 301       m_derived_ct, decl, name.str().c_str(), enumerator.Value);
 302   return Error::success();
 303 }
 304
 305 void UdtRecordCompleter::complete() {
 306   // Ensure the correct order for virtual bases.
 307   llvm::stable_sort(m_bases, llvm::less_first());
 308
 309   std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> bases;
 310   bases.reserve(m_bases.size());
 311   for (auto &ib : m_bases)
 312     bases.push_back(std::move(ib.second));
 313
 314   TypeSystemClang &clang = m_ast_builder.clang();
 315   // Make sure all base classes refer to complete types and not forward
 316   // declarations. If we don't do this, clang will crash with an
 317   // assertion in the call to clang_type.TransferBaseClasses()
 318   for (const auto &base_class : bases) {
 319     clang::TypeSourceInfo *type_source_info =
 320         base_class->getTypeSourceInfo();
 321     if (type_source_info) {
 322       TypeSystemClang::RequireCompleteType(
 323           clang.GetType(type_source_info->getType()));
 324     }
 325   }
 326
 327   clang.TransferBaseClasses(m_derived_ct.GetOpaqueQualType(), std::move(bases));
 328
 329   clang.AddMethodOverridesForCXXRecordType(m_derived_ct.GetOpaqueQualType());
 330   FinishRecord();
 331   TypeSystemClang::BuildIndirectFields(m_derived_ct);
 332   TypeSystemClang::CompleteTagDeclarationDefinition(m_derived_ct);
 333
 334   if (auto *record_decl = llvm::dyn_cast<clang::CXXRecordDecl>(&m_tag_decl)) {
 335     m_ast_builder.GetClangASTImporter().SetRecordLayout(record_decl, m_layout);
 336   }
 337 }
 338
 339 uint64_t
 340 UdtRecordCompleter::AddMember(TypeSystemClang &clang, Member *field,
 341                               uint64_t bit_offset, CompilerType parent_ct,
 342                               ClangASTImporter::LayoutInfo &parent_layout,
 343                               clang::DeclContext *parent_decl_ctx) {
 344   SymbolFileNativePDB *pdb = static_cast<SymbolFileNativePDB *>(
 345       clang.GetSymbolFile()->GetBackingSymbolFile());
 346   clang::FieldDecl *field_decl = nullptr;
 347   uint64_t bit_size = 0;
 348   switch (field->kind) {
 349   case Member::Field: {
 350     field_decl = TypeSystemClang::AddFieldToRecordType(
 351         parent_ct, field->name, m_ast_builder.ToCompilerType(field->qt),
 352         field->access, field->bitfield_width);
 353     bit_size = field->bit_size;
 354     break;
 355   };
 356   case Member::Struct:
 357   case Member::Union: {
 358     clang::TagTypeKind kind = field->kind == Member::Struct
 359                                   ? clang::TagTypeKind::TTK_Struct
 360                                   : clang::TagTypeKind::TTK_Union;
 361     ClangASTMetadata metadata;
 362     metadata.SetUserID(pdb->anonymous_id);
 363     metadata.SetIsDynamicCXXType(false);
 364     CompilerType record_ct = clang.CreateRecordType(
 365         parent_decl_ctx, OptionalClangModuleID(), lldb::eAccessPublic, "", kind,
 366         lldb::eLanguageTypeC_plus_plus, &metadata);
 367     TypeSystemClang::StartTagDeclarationDefinition(record_ct);
 368     ClangASTImporter::LayoutInfo layout;
 369     clang::DeclContext *decl_ctx = clang.GetDeclContextForType(record_ct);
 370     for (const auto &member : field->fields) {
 371       uint64_t member_offset = field->kind == Member::Struct
 372                                    ? member->bit_offset - field->base_offset
 373                                    : 0;
 374       uint64_t member_bit_size = AddMember(clang, member.get(), member_offset,
 375                                           record_ct, layout, decl_ctx);
 376       if (field->kind == Member::Struct)
 377         bit_size = std::max(bit_size, member_offset + member_bit_size);
 378       else
 379         bit_size = std::max(bit_size, member_bit_size);
 380     }
 381     layout.bit_size = bit_size;
 382     TypeSystemClang::CompleteTagDeclarationDefinition(record_ct);
 383     clang::RecordDecl *record_decl = clang.GetAsRecordDecl(record_ct);
 384     m_ast_builder.GetClangASTImporter().SetRecordLayout(record_decl, layout);
 385     field_decl = TypeSystemClang::AddFieldToRecordType(
 386         parent_ct, "", record_ct, lldb::eAccessPublic, 0);
 387     // Mark this record decl as completed.
 388     DeclStatus status;
 389     status.resolved = true;
 390     status.uid = pdb->anonymous_id--;
 391     m_decl_to_status.insert({record_decl, status});
 392     break;
 393   };
 394   }
 395   // FIXME: Add a PdbSymUid namespace for field list members and update
 396   // the m_uid_to_decl map with this decl.
 397   parent_layout.field_offsets.insert({field_decl, bit_offset});
 398   return bit_size;
 399 }
 400
 401 void UdtRecordCompleter::FinishRecord() {
 402   TypeSystemClang &clang = m_ast_builder.clang();
 403   clang::DeclContext *decl_ctx =
 404       m_ast_builder.GetOrCreateDeclContextForUid(m_id);
 405   m_record.ConstructRecord();
 406   // Maybe we should check the construsted record size with the size in pdb. If
 407   // they mismatch, it might be pdb has fields info missing.
 408   for (const auto &field : m_record.record.fields) {
 409     AddMember(clang, field.get(), field->bit_offset, m_derived_ct, m_layout,
 410              decl_ctx);
 411   }
 412 }
 413
 414 void UdtRecordCompleter::Record::CollectMember(
 415     llvm::StringRef name, uint64_t offset, uint64_t field_size,
 416     clang::QualType qt, lldb::AccessType access, uint64_t bitfield_width) {
 417   fields_map[offset].push_back(std::make_unique<Member>(
 418       name, offset, field_size, qt, access, bitfield_width));
 419   if (start_offset > offset)
 420     start_offset = offset;
 421 }
 422
 423 void UdtRecordCompleter::Record::ConstructRecord() {
 424   // For anonymous unions in a struct, msvc generated pdb doesn't have the
 425   // entity for that union. So, we need to construct anonymous union and struct
 426   // based on field offsets. The final AST is likely not matching the exact
 427   // original AST, but the memory layout is preseved.
 428   // After we collecting all fields in visitKnownMember, we have all fields in
 429   // increasing offset order in m_fields. Since we are iterating in increase
 430   // offset order, if the current offset is equal to m_start_offset, we insert
 431   // it as direct field of top level record. If the current offset is greater
 432   // than m_start_offset, we should be able to find a field in end_offset_map
 433   // whose end offset is less than or equal to current offset. (if not, it might
 434   // be missing field info. We will ignore the field in this case. e.g. Field A
 435   // starts at 0 with size 4 bytes, and Field B starts at 2 with size 4 bytes.
 436   // Normally, there must be something which ends at/before 2.) Then we will
 437   // append current field to the end of parent record. If parent is struct, we
 438   // can just grow it. If parent is a field, it's a field inside an union. We
 439   // convert it into an anonymous struct containing old field and new field.
 440
 441   // The end offset to a vector of field/struct that ends at the offset.
 442   std::map<uint64_t, std::vector<Member *>> end_offset_map;
 443   for (auto &pair : fields_map) {
 444     uint64_t offset = pair.first;
 445     auto &fields = pair.second;
 446     lldbassert(offset >= start_offset);
 447     Member *parent = &record;
 448     if (offset > start_offset) {
 449       // Find the field with largest end offset that is <= offset. If it's less
 450       // than offset, it indicates there are padding bytes between end offset
 451       // and offset.
 452       lldbassert(!end_offset_map.empty());
 453       auto iter = end_offset_map.lower_bound(offset);
 454       if (iter == end_offset_map.end())
 455         --iter;
 456       else if (iter->first > offset) {
 457         if (iter == end_offset_map.begin())
 458           continue;
 459         --iter;
 460       }
 461       if (iter->second.empty())
 462         continue;
 463       parent = iter->second.back();
 464       iter->second.pop_back();
 465     }
 466     // If it's a field, then the field is inside a union, so we can safely
 467     // increase its size by converting it to a struct to hold multiple fields.
 468     if (parent->kind == Member::Field)
 469       parent->ConvertToStruct();
 470
 471     if (fields.size() == 1) {
 472       uint64_t end_offset = offset + fields.back()->bit_size;
 473       parent->fields.push_back(std::move(fields.back()));
 474       if (parent->kind == Member::Struct) {
 475         end_offset_map[end_offset].push_back(parent);
 476       } else {
 477         lldbassert(parent == &record &&
 478                    "If parent is union, it must be the top level record.");
 479         end_offset_map[end_offset].push_back(parent->fields.back().get());
 480       }
 481     } else {
 482       if (parent->kind == Member::Struct) {
 483         parent->fields.push_back(std::make_unique<Member>(Member::Union));
 484         parent = parent->fields.back().get();
 485         parent->bit_offset = offset;
 486       } else {
 487         lldbassert(parent == &record &&
 488                    "If parent is union, it must be the top level record.");
 489       }
 490       for (auto &field : fields) {
 491         int64_t bit_size = field->bit_size;
 492         parent->fields.push_back(std::move(field));
 493         end_offset_map[offset + bit_size].push_back(
 494             parent->fields.back().get());
 495       }
 496     }
 497   }
 498 }