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