1 //===- GlobalTypeTableBuilder.h ----------------------------------*- C++-*-===//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_DEBUGINFO_CODEVIEW_GLOBALTYPETABLEBUILDER_H
10 #define LLVM_DEBUGINFO_CODEVIEW_GLOBALTYPETABLEBUILDER_H
11 
12 #include "llvm/ADT/ArrayRef.h"
13 #include "llvm/ADT/DenseSet.h"
14 #include "llvm/ADT/SmallVector.h"
15 #include "llvm/DebugInfo/CodeView/CodeView.h"
16 #include "llvm/DebugInfo/CodeView/SimpleTypeSerializer.h"
17 #include "llvm/DebugInfo/CodeView/TypeCollection.h"
18 #include "llvm/DebugInfo/CodeView/TypeHashing.h"
19 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
20 #include "llvm/Support/Allocator.h"
21 #include <cassert>
22 #include <cstdint>
23 #include <memory>
24 #include <vector>
25 
26 namespace llvm {
27 namespace codeview {
28 
29 class ContinuationRecordBuilder;
30 
31 class GlobalTypeTableBuilder : public TypeCollection {
32   /// Storage for records.  These need to outlive the TypeTableBuilder.
33   BumpPtrAllocator &RecordStorage;
34 
35   /// A serializer that can write non-continuation leaf types.  Only used as
36   /// a convenience function so that we can provide an interface method to
37   /// write an unserialized record.
38   SimpleTypeSerializer SimpleSerializer;
39 
40   /// Hash table.
41   DenseMap<GloballyHashedType, TypeIndex> HashedRecords;
42 
43   /// Contains a list of all records indexed by TypeIndex.toArrayIndex().
44   SmallVector<ArrayRef<uint8_t>, 2> SeenRecords;
45 
46   /// Contains a list of all hash values indexed by TypeIndex.toArrayIndex().
47   SmallVector<GloballyHashedType, 2> SeenHashes;
48 
49 public:
50   explicit GlobalTypeTableBuilder(BumpPtrAllocator &Storage);
51   ~GlobalTypeTableBuilder();
52 
53   // TypeCollection overrides
54   Optional<TypeIndex> getFirst() override;
55   Optional<TypeIndex> getNext(TypeIndex Prev) override;
56   CVType getType(TypeIndex Index) override;
57   StringRef getTypeName(TypeIndex Index) override;
58   bool contains(TypeIndex Index) override;
59   uint32_t size() override;
60   uint32_t capacity() override;
61   bool replaceType(TypeIndex &Index, CVType Data, bool Stabilize) override;
62 
63   // public interface
64   void reset();
65   TypeIndex nextTypeIndex() const;
66 
getAllocator()67   BumpPtrAllocator &getAllocator() { return RecordStorage; }
68 
69   ArrayRef<ArrayRef<uint8_t>> records() const;
70   ArrayRef<GloballyHashedType> hashes() const;
71 
72   template <typename CreateFunc>
insertRecordAs(GloballyHashedType Hash,size_t RecordSize,CreateFunc Create)73   TypeIndex insertRecordAs(GloballyHashedType Hash, size_t RecordSize,
74                            CreateFunc Create) {
75     assert(RecordSize < UINT32_MAX && "Record too big");
76     assert(RecordSize % 4 == 0 &&
77            "RecordSize is not a multiple of 4 bytes which will cause "
78            "misalignment in the output TPI stream!");
79 
80     auto Result = HashedRecords.try_emplace(Hash, nextTypeIndex());
81 
82     if (LLVM_UNLIKELY(Result.second /*inserted*/ ||
83                       Result.first->second.isSimple())) {
84       uint8_t *Stable = RecordStorage.Allocate<uint8_t>(RecordSize);
85       MutableArrayRef<uint8_t> Data(Stable, RecordSize);
86       ArrayRef<uint8_t> StableRecord = Create(Data);
87       if (StableRecord.empty()) {
88         // Records with forward references into the Type stream will be deferred
89         // for insertion at a later time, on the second pass.
90         Result.first->getSecond() = TypeIndex(SimpleTypeKind::NotTranslated);
91         return TypeIndex(SimpleTypeKind::NotTranslated);
92       }
93       if (Result.first->second.isSimple()) {
94         assert(Result.first->second.getIndex() ==
95                (uint32_t)SimpleTypeKind::NotTranslated);
96         // On the second pass, update with index to remapped record. The
97         // (initially misbehaved) record will now come *after* other records
98         // resolved in the first pass, with proper *back* references in the
99         // stream.
100         Result.first->second = nextTypeIndex();
101       }
102       SeenRecords.push_back(StableRecord);
103       SeenHashes.push_back(Hash);
104     }
105 
106     return Result.first->second;
107   }
108 
109   TypeIndex insertRecordBytes(ArrayRef<uint8_t> Data);
110   TypeIndex insertRecord(ContinuationRecordBuilder &Builder);
111 
writeLeafType(T & Record)112   template <typename T> TypeIndex writeLeafType(T &Record) {
113     ArrayRef<uint8_t> Data = SimpleSerializer.serialize(Record);
114     return insertRecordBytes(Data);
115   }
116 };
117 
118 } // end namespace codeview
119 } // end namespace llvm
120 
121 #endif // LLVM_DEBUGINFO_CODEVIEW_MERGINGTYPETABLEBUILDER_H
122