1 //===- GlobalTypeTableBuilder.cpp -----------------------------------------===//
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 #include "llvm/DebugInfo/CodeView/GlobalTypeTableBuilder.h"
10 #include "llvm/ADT/ArrayRef.h"
11 #include "llvm/ADT/None.h"
12 #include "llvm/DebugInfo/CodeView/CodeView.h"
13 #include "llvm/DebugInfo/CodeView/ContinuationRecordBuilder.h"
14 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
15 #include "llvm/Support/Allocator.h"
16 #include "llvm/Support/ErrorHandling.h"
17 #include <cassert>
18 #include <cstdint>
19 #include <cstring>
20 
21 using namespace llvm;
22 using namespace llvm::codeview;
23 
24 TypeIndex GlobalTypeTableBuilder::nextTypeIndex() const {
25   return TypeIndex::fromArrayIndex(SeenRecords.size());
26 }
27 
28 GlobalTypeTableBuilder::GlobalTypeTableBuilder(BumpPtrAllocator &Storage)
29     : RecordStorage(Storage) {
30   SeenRecords.reserve(4096);
31 }
32 
33 GlobalTypeTableBuilder::~GlobalTypeTableBuilder() = default;
34 
35 Optional<TypeIndex> GlobalTypeTableBuilder::getFirst() {
36   if (empty())
37     return None;
38 
39   return TypeIndex(TypeIndex::FirstNonSimpleIndex);
40 }
41 
42 Optional<TypeIndex> GlobalTypeTableBuilder::getNext(TypeIndex Prev) {
43   if (++Prev == nextTypeIndex())
44     return None;
45   return Prev;
46 }
47 
48 CVType GlobalTypeTableBuilder::getType(TypeIndex Index) {
49   CVType Type(SeenRecords[Index.toArrayIndex()]);
50   return Type;
51 }
52 
53 StringRef GlobalTypeTableBuilder::getTypeName(TypeIndex Index) {
54   llvm_unreachable("Method not implemented");
55 }
56 
57 bool GlobalTypeTableBuilder::contains(TypeIndex Index) {
58   if (Index.isSimple() || Index.isNoneType())
59     return false;
60 
61   return Index.toArrayIndex() < SeenRecords.size();
62 }
63 
64 uint32_t GlobalTypeTableBuilder::size() { return SeenRecords.size(); }
65 
66 uint32_t GlobalTypeTableBuilder::capacity() { return SeenRecords.size(); }
67 
68 ArrayRef<ArrayRef<uint8_t>> GlobalTypeTableBuilder::records() const {
69   return SeenRecords;
70 }
71 
72 ArrayRef<GloballyHashedType> GlobalTypeTableBuilder::hashes() const {
73   return SeenHashes;
74 }
75 
76 void GlobalTypeTableBuilder::reset() {
77   HashedRecords.clear();
78   SeenRecords.clear();
79 }
80 
81 static inline ArrayRef<uint8_t> stabilize(BumpPtrAllocator &Alloc,
82                                           ArrayRef<uint8_t> Data) {
83   uint8_t *Stable = Alloc.Allocate<uint8_t>(Data.size());
84   memcpy(Stable, Data.data(), Data.size());
85   return makeArrayRef(Stable, Data.size());
86 }
87 
88 TypeIndex GlobalTypeTableBuilder::insertRecordBytes(ArrayRef<uint8_t> Record) {
89   GloballyHashedType GHT =
90       GloballyHashedType::hashType(Record, SeenHashes, SeenHashes);
91   return insertRecordAs(GHT, Record.size(),
92                         [Record](MutableArrayRef<uint8_t> Data) {
93                           assert(Data.size() == Record.size());
94                           ::memcpy(Data.data(), Record.data(), Record.size());
95                           return Data;
96                         });
97 }
98 
99 TypeIndex
100 GlobalTypeTableBuilder::insertRecord(ContinuationRecordBuilder &Builder) {
101   TypeIndex TI;
102   auto Fragments = Builder.end(nextTypeIndex());
103   assert(!Fragments.empty());
104   for (auto C : Fragments)
105     TI = insertRecordBytes(C.RecordData);
106   return TI;
107 }
108 
109 bool GlobalTypeTableBuilder::replaceType(TypeIndex &Index, CVType Data,
110                                          bool Stabilize) {
111   assert(Index.toArrayIndex() < SeenRecords.size() &&
112          "This function cannot be used to insert records!");
113 
114   ArrayRef<uint8_t> Record = Data.data();
115   assert(Record.size() < UINT32_MAX && "Record too big");
116   assert(Record.size() % 4 == 0 &&
117          "The type record size is not a multiple of 4 bytes which will cause "
118          "misalignment in the output TPI stream!");
119 
120   GloballyHashedType Hash =
121       GloballyHashedType::hashType(Record, SeenHashes, SeenHashes);
122   auto Result = HashedRecords.try_emplace(Hash, Index.toArrayIndex());
123   if (!Result.second) {
124     Index = Result.first->second;
125     return false; // The record is already there, at a different location
126   }
127 
128   if (Stabilize)
129     Record = stabilize(RecordStorage, Record);
130 
131   SeenRecords[Index.toArrayIndex()] = Record;
132   SeenHashes[Index.toArrayIndex()] = Hash;
133   return true;
134 }
135