llvm/lib/DebugInfo/CodeView/MergingTypeTableBuilder.cpp

   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/ADT/DenseSet.h"
  12 #include "llvm/ADT/STLExtras.h"
  13 #include "llvm/DebugInfo/CodeView/CodeView.h"
  14 #include "llvm/DebugInfo/CodeView/ContinuationRecordBuilder.h"
  15 #include "llvm/DebugInfo/CodeView/RecordSerialization.h"
  16 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
  17 #include "llvm/Support/Allocator.h"
  18 #include "llvm/Support/BinaryByteStream.h"
  19 #include "llvm/Support/BinaryStreamWriter.h"
  20 #include "llvm/Support/Endian.h"
  21 #include "llvm/Support/Error.h"
  22 #include <algorithm>
  23 #include <cassert>
  24 #include <cstdint>
  25 #include <cstring>
  26
  27 using namespace llvm;
  28 using namespace llvm::codeview;
  29
  30 TypeIndex MergingTypeTableBuilder::nextTypeIndex() const {
  31   return TypeIndex::fromArrayIndex(SeenRecords.size());
  32 }
  33
  34 MergingTypeTableBuilder::MergingTypeTableBuilder(BumpPtrAllocator &Storage)
  35     : RecordStorage(Storage) {
  36   SeenRecords.reserve(4096);
  37 }
  38
  39 MergingTypeTableBuilder::~MergingTypeTableBuilder() = default;
  40
  41 Optional<TypeIndex> MergingTypeTableBuilder::getFirst() {
  42   if (empty())
  43     return None;
  44
  45   return TypeIndex(TypeIndex::FirstNonSimpleIndex);
  46 }
  47
  48 Optional<TypeIndex> MergingTypeTableBuilder::getNext(TypeIndex Prev) {
  49   if (++Prev == nextTypeIndex())
  50     return None;
  51   return Prev;
  52 }
  53
  54 CVType MergingTypeTableBuilder::getType(TypeIndex Index) {
  55   CVType Type(SeenRecords[Index.toArrayIndex()]);
  56   return Type;
  57 }
  58
  59 StringRef MergingTypeTableBuilder::getTypeName(TypeIndex Index) {
  60   llvm_unreachable("Method not implemented");
  61 }
  62
  63 bool MergingTypeTableBuilder::contains(TypeIndex Index) {
  64   if (Index.isSimple() || Index.isNoneType())
  65     return false;
  66
  67   return Index.toArrayIndex() < SeenRecords.size();
  68 }
  69
  70 uint32_t MergingTypeTableBuilder::size() { return SeenRecords.size(); }
  71
  72 uint32_t MergingTypeTableBuilder::capacity() { return SeenRecords.size(); }
  73
  74 ArrayRef<ArrayRef<uint8_t>> MergingTypeTableBuilder::records() const {
  75   return SeenRecords;
  76 }
  77
  78 void MergingTypeTableBuilder::reset() {
  79   HashedRecords.clear();
  80   SeenRecords.clear();
  81 }
  82
  83 static inline ArrayRef<uint8_t> stabilize(BumpPtrAllocator &Alloc,
  84                                           ArrayRef<uint8_t> Data) {
  85   uint8_t *Stable = Alloc.Allocate<uint8_t>(Data.size());
  86   memcpy(Stable, Data.data(), Data.size());
  87   return makeArrayRef(Stable, Data.size());
  88 }
  89
  90 TypeIndex MergingTypeTableBuilder::insertRecordAs(hash_code Hash,
  91                                                   ArrayRef<uint8_t> &Record) {
  92   assert(Record.size() < UINT32_MAX && "Record too big");
  93   assert(Record.size() % 4 == 0 &&
  94          "The type record size is not a multiple of 4 bytes which will cause "
  95          "misalignment in the output TPI stream!");
  96
  97   LocallyHashedType WeakHash{Hash, Record};
  98   auto Result = HashedRecords.try_emplace(WeakHash, nextTypeIndex());
  99
 100   if (Result.second) {
 101     ArrayRef<uint8_t> RecordData = stabilize(RecordStorage, Record);
 102     Result.first->first.RecordData = RecordData;
 103     SeenRecords.push_back(RecordData);
 104   }
 105
 106   // Update the caller's copy of Record to point a stable copy.
 107   TypeIndex ActualTI = Result.first->second;
 108   Record = SeenRecords[ActualTI.toArrayIndex()];
 109   return ActualTI;
 110 }
 111
 112 TypeIndex
 113 MergingTypeTableBuilder::insertRecordBytes(ArrayRef<uint8_t> &Record) {
 114   return insertRecordAs(hash_value(Record), Record);
 115 }
 116
 117 TypeIndex
 118 MergingTypeTableBuilder::insertRecord(ContinuationRecordBuilder &Builder) {
 119   TypeIndex TI;
 120   auto Fragments = Builder.end(nextTypeIndex());
 121   assert(!Fragments.empty());
 122   for (auto C : Fragments)
 123     TI = insertRecordBytes(C.RecordData);
 124   return TI;
 125 }
 126
 127 bool MergingTypeTableBuilder::replaceType(TypeIndex &Index, CVType Data,
 128                                           bool Stabilize) {
 129   assert(Index.toArrayIndex() < SeenRecords.size() &&
 130          "This function cannot be used to insert records!");
 131
 132   ArrayRef<uint8_t> Record = Data.data();
 133   assert(Record.size() < UINT32_MAX && "Record too big");
 134   assert(Record.size() % 4 == 0 &&
 135          "The type record size is not a multiple of 4 bytes which will cause "
 136          "misalignment in the output TPI stream!");
 137
 138   LocallyHashedType WeakHash{hash_value(Record), Record};
 139   auto Result = HashedRecords.try_emplace(WeakHash, Index.toArrayIndex());
 140   if (!Result.second) {
 141     Index = Result.first->second;
 142     return false; // The record is already there, at a different location
 143   }
 144
 145   if (Stabilize) {
 146     Record = stabilize(RecordStorage, Record);
 147     Result.first->first.RecordData = Record;
 148   }
 149
 150   SeenRecords[Index.toArrayIndex()] = Record;
 151   return true;
 152 }