1//===- MergingTypeTableBuilder.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/MergingTypeTableBuilder.h"
10#include "llvm/ADT/ArrayRef.h"
11#include "llvm/DebugInfo/CodeView/CodeView.h"
12#include "llvm/DebugInfo/CodeView/ContinuationRecordBuilder.h"
13#include "llvm/DebugInfo/CodeView/TypeHashing.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
21using namespace llvm;
22using namespace llvm::codeview;
23
24TypeIndex MergingTypeTableBuilder::nextTypeIndex() const {
25  return TypeIndex::fromArrayIndex(SeenRecords.size());
26}
27
28MergingTypeTableBuilder::MergingTypeTableBuilder(BumpPtrAllocator &Storage)
29    : RecordStorage(Storage) {
30  SeenRecords.reserve(4096);
31}
32
33MergingTypeTableBuilder::~MergingTypeTableBuilder() = default;
34
35std::optional<TypeIndex> MergingTypeTableBuilder::getFirst() {
36  if (empty())
37    return std::nullopt;
38
39  return TypeIndex(TypeIndex::FirstNonSimpleIndex);
40}
41
42std::optional<TypeIndex> MergingTypeTableBuilder::getNext(TypeIndex Prev) {
43  if (++Prev == nextTypeIndex())
44    return std::nullopt;
45  return Prev;
46}
47
48CVType MergingTypeTableBuilder::getType(TypeIndex Index) {
49  CVType Type(SeenRecords[Index.toArrayIndex()]);
50  return Type;
51}
52
53StringRef MergingTypeTableBuilder::getTypeName(TypeIndex Index) {
54  llvm_unreachable("Method not implemented");
55}
56
57bool MergingTypeTableBuilder::contains(TypeIndex Index) {
58  if (Index.isSimple() || Index.isNoneType())
59    return false;
60
61  return Index.toArrayIndex() < SeenRecords.size();
62}
63
64uint32_t MergingTypeTableBuilder::size() { return SeenRecords.size(); }
65
66uint32_t MergingTypeTableBuilder::capacity() { return SeenRecords.size(); }
67
68ArrayRef<ArrayRef<uint8_t>> MergingTypeTableBuilder::records() const {
69  return SeenRecords;
70}
71
72void MergingTypeTableBuilder::reset() {
73  HashedRecords.clear();
74  SeenRecords.clear();
75}
76
77static inline ArrayRef<uint8_t> stabilize(BumpPtrAllocator &Alloc,
78                                          ArrayRef<uint8_t> Data) {
79  uint8_t *Stable = Alloc.Allocate<uint8_t>(Data.size());
80  memcpy(Stable, Data.data(), Data.size());
81  return ArrayRef(Stable, Data.size());
82}
83
84TypeIndex MergingTypeTableBuilder::insertRecordAs(hash_code Hash,
85                                                  ArrayRef<uint8_t> &Record) {
86  assert(Record.size() < UINT32_MAX && "Record too big");
87  assert(Record.size() % 4 == 0 &&
88         "The type record size is not a multiple of 4 bytes which will cause "
89         "misalignment in the output TPI stream!");
90
91  LocallyHashedType WeakHash{Hash, Record};
92  auto Result = HashedRecords.try_emplace(WeakHash, nextTypeIndex());
93
94  if (Result.second) {
95    ArrayRef<uint8_t> RecordData = stabilize(RecordStorage, Record);
96    Result.first->first.RecordData = RecordData;
97    SeenRecords.push_back(RecordData);
98  }
99
100  // Update the caller's copy of Record to point a stable copy.
101  TypeIndex ActualTI = Result.first->second;
102  Record = SeenRecords[ActualTI.toArrayIndex()];
103  return ActualTI;
104}
105
106TypeIndex
107MergingTypeTableBuilder::insertRecordBytes(ArrayRef<uint8_t> &Record) {
108  return insertRecordAs(hash_value(Record), Record);
109}
110
111TypeIndex
112MergingTypeTableBuilder::insertRecord(ContinuationRecordBuilder &Builder) {
113  TypeIndex TI;
114  auto Fragments = Builder.end(nextTypeIndex());
115  assert(!Fragments.empty());
116  for (auto C : Fragments)
117    TI = insertRecordBytes(C.RecordData);
118  return TI;
119}
120
121bool MergingTypeTableBuilder::replaceType(TypeIndex &Index, CVType Data,
122                                          bool Stabilize) {
123  assert(Index.toArrayIndex() < SeenRecords.size() &&
124         "This function cannot be used to insert records!");
125
126  ArrayRef<uint8_t> Record = Data.data();
127  assert(Record.size() < UINT32_MAX && "Record too big");
128  assert(Record.size() % 4 == 0 &&
129         "The type record size is not a multiple of 4 bytes which will cause "
130         "misalignment in the output TPI stream!");
131
132  LocallyHashedType WeakHash{hash_value(Record), Record};
133  auto Result = HashedRecords.try_emplace(WeakHash, Index.toArrayIndex());
134  if (!Result.second) {
135    Index = Result.first->second;
136    return false; // The record is already there, at a different location
137  }
138
139  if (Stabilize) {
140    Record = stabilize(RecordStorage, Record);
141    Result.first->first.RecordData = Record;
142  }
143
144  SeenRecords[Index.toArrayIndex()] = Record;
145  return true;
146}
147