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 inexed by TypeIndex.toArrayIndex().
47   SmallVector<GloballyHashedType, 2> SeenHashes;
48 
49 public:
50   explicit GlobalTypeTableBuilder(BumpPtrAllocator &Storage);
51   ~GlobalTypeTableBuilder();
52 
53   // TypeTableCollection 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 
62   // public interface
63   void reset();
64   TypeIndex nextTypeIndex() const;
65 
66   BumpPtrAllocator &getAllocator() { return RecordStorage; }
67 
68   ArrayRef<ArrayRef<uint8_t>> records() const;
69   ArrayRef<GloballyHashedType> hashes() const;
70 
71   template <typename CreateFunc>
72   TypeIndex insertRecordAs(GloballyHashedType Hash, size_t RecordSize,
73                            CreateFunc Create) {
74     auto Result = HashedRecords.try_emplace(Hash, nextTypeIndex());
75 
76     if (LLVM_UNLIKELY(Result.second /*inserted*/ ||
77                       Result.first->second.isSimple())) {
78       uint8_t *Stable = RecordStorage.Allocate<uint8_t>(RecordSize);
79       MutableArrayRef<uint8_t> Data(Stable, RecordSize);
80       ArrayRef<uint8_t> StableRecord = Create(Data);
81       if (StableRecord.empty()) {
82         // Records with forward references into the Type stream will be deferred
83         // for insertion at a later time, on the second pass.
84         Result.first->getSecond() = TypeIndex(SimpleTypeKind::NotTranslated);
85         return TypeIndex(SimpleTypeKind::NotTranslated);
86       }
87       if (Result.first->second.isSimple()) {
88         assert(Result.first->second.getIndex() ==
89                (uint32_t)SimpleTypeKind::NotTranslated);
90         // On the second pass, update with index to remapped record. The
91         // (initially misbehaved) record will now come *after* other records
92         // resolved in the first pass, with proper *back* references in the
93         // stream.
94         Result.first->second = nextTypeIndex();
95       }
96       SeenRecords.push_back(StableRecord);
97       SeenHashes.push_back(Hash);
98     }
99 
100     return Result.first->second;
101   }
102 
103   TypeIndex insertRecordBytes(ArrayRef<uint8_t> Data);
104   TypeIndex insertRecord(ContinuationRecordBuilder &Builder);
105 
106   template <typename T> TypeIndex writeLeafType(T &Record) {
107     ArrayRef<uint8_t> Data = SimpleSerializer.serialize(Record);
108     return insertRecordBytes(Data);
109   }
110 };
111 
112 } // end namespace codeview
113 } // end namespace llvm
114 
115 #endif // LLVM_DEBUGINFO_CODEVIEW_MERGINGTYPETABLEBUILDER_H
116