1 //===- TypeReferenceTracker.cpp ------------------------------- *- C++ --*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 #include "TypeReferenceTracker.h"
11 #include "llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
12 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
13 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
14 #include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
15 #include "llvm/DebugInfo/PDB/Native/SymbolStream.h"
18 using namespace llvm::pdb;
19 using namespace llvm::codeview;
21 // LazyRandomTypeCollection doesn't appear to expose the number of records, so
22 // just iterate up front to find out.
23 static uint32_t getNumRecordsInCollection(LazyRandomTypeCollection &Types) {
24 uint32_t NumTypes = 0;
25 for (Optional<TypeIndex> TI = Types.getFirst(); TI; TI = Types.getNext(*TI))
30 TypeReferenceTracker::TypeReferenceTracker(InputFile &File)
31 : File(File), Types(File.types()),
32 Ids(File.isPdb() ? &File.ids() : nullptr) {
33 NumTypeRecords = getNumRecordsInCollection(Types);
34 TypeReferenced.resize(NumTypeRecords, false);
36 // If this is a PDB, ids are stored separately, so make a separate bit vector.
38 NumIdRecords = getNumRecordsInCollection(*Ids);
39 IdReferenced.resize(NumIdRecords, false);
42 // Get the TpiStream pointer for forward decl resolution if this is a pdb.
43 // Build the hash map to enable resolving forward decls.
45 Tpi = &cantFail(File.pdb().getPDBTpiStream());
50 void TypeReferenceTracker::mark() {
54 // - LF_UDT_MOD_SRC_LINE? VC always links these in.
55 for (SymbolGroup SG : File.symbol_groups()) {
57 for (const auto &SS : SG.getDebugSubsections()) {
58 // FIXME: Are there other type-referencing subsections? Inlinees?
60 if (SS.kind() != DebugSubsectionKind::Symbols)
63 CVSymbolArray Symbols;
64 BinaryStreamReader Reader(SS.getRecordData());
65 cantFail(Reader.readArray(Symbols, Reader.getLength()));
66 for (const CVSymbol &S : Symbols)
67 addTypeRefsFromSymbol(S);
69 } else if (SG.hasDebugStream()) {
70 for (const CVSymbol &S : SG.getPdbModuleStream().getSymbolArray())
71 addTypeRefsFromSymbol(S);
75 // Walk globals and mark types referenced from globals.
76 if (File.isPdb() && File.pdb().hasPDBGlobalsStream()) {
77 SymbolStream &SymStream = cantFail(File.pdb().getPDBSymbolStream());
78 GlobalsStream &GS = cantFail(File.pdb().getPDBGlobalsStream());
79 for (uint32_t PubSymOff : GS.getGlobalsTable()) {
80 CVSymbol Sym = SymStream.readRecord(PubSymOff);
81 addTypeRefsFromSymbol(Sym);
85 // FIXME: Should we walk Ids?
88 void TypeReferenceTracker::addOneTypeRef(TiRefKind RefKind, TypeIndex RefTI) {
89 // If it's simple or already seen, no need to add to work list.
90 BitVector &TypeOrIdReferenced =
91 (Ids && RefKind == TiRefKind::IndexRef) ? IdReferenced : TypeReferenced;
92 if (RefTI.isSimple() || TypeOrIdReferenced.test(RefTI.toArrayIndex()))
95 // Otherwise, mark it seen and add it to the work list.
96 TypeOrIdReferenced.set(RefTI.toArrayIndex());
97 RefWorklist.push_back({RefKind, RefTI});
100 void TypeReferenceTracker::addTypeRefsFromSymbol(const CVSymbol &Sym) {
101 SmallVector<TiReference, 4> DepList;
102 // FIXME: Check for failure.
103 discoverTypeIndicesInSymbol(Sym, DepList);
104 addReferencedTypes(Sym.content(), DepList);
105 markReferencedTypes();
108 void TypeReferenceTracker::addReferencedTypes(ArrayRef<uint8_t> RecData,
109 ArrayRef<TiReference> DepList) {
110 for (const auto &Ref : DepList) {
111 // FIXME: Report OOB slice instead of truncating.
112 ArrayRef<uint8_t> ByteSlice =
113 RecData.drop_front(Ref.Offset).take_front(4 * Ref.Count);
114 ArrayRef<TypeIndex> TIs(
115 reinterpret_cast<const TypeIndex *>(ByteSlice.data()),
116 ByteSlice.size() / 4);
118 // If this is a PDB and this is an item reference, track it in the IPI
119 // bitvector. Otherwise, it's a type ref, or there is only one stream.
120 for (TypeIndex RefTI : TIs)
121 addOneTypeRef(Ref.Kind, RefTI);
125 void TypeReferenceTracker::markReferencedTypes() {
126 while (!RefWorklist.empty()) {
129 std::tie(RefKind, RefTI) = RefWorklist.pop_back_val();
130 Optional<CVType> Rec = (Ids && RefKind == TiRefKind::IndexRef)
131 ? Ids->tryGetType(RefTI)
132 : Types.tryGetType(RefTI);
134 continue; // FIXME: Report a reference to a non-existant type.
136 SmallVector<TiReference, 4> DepList;
137 // FIXME: Check for failure.
138 discoverTypeIndices(*Rec, DepList);
139 addReferencedTypes(Rec->content(), DepList);
141 // If this is a tag kind and this is a PDB input, mark the complete type as
143 // FIXME: This limitation makes this feature somewhat useless on object file
146 switch (Rec->kind()) {
154 addOneTypeRef(TiRefKind::TypeRef,
155 cantFail(Tpi->findFullDeclForForwardRef(RefTI)));