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/DebugInfo/CodeView/ContinuationRecordBuilder.h"
  12 #include "llvm/DebugInfo/CodeView/TypeHashing.h"
  13 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
  14 #include "llvm/Support/Allocator.h"
  15 #include "llvm/Support/ErrorHandling.h"
  16 #include <cassert>
  17 #include <cstdint>
  18 #include <cstring>
  19
  20 using namespace llvm;
  21 using namespace llvm::codeview;
  22
  23 TypeIndex MergingTypeTableBuilder::nextTypeIndex() const {
  24   return TypeIndex::fromArrayIndex(SeenRecords.size());
  25 }
  26
  27 MergingTypeTableBuilder::MergingTypeTableBuilder(BumpPtrAllocator &Storage)
  28     : RecordStorage(Storage) {
  29   SeenRecords.reserve(4096);
  30 }
  31
  32 MergingTypeTableBuilder::~MergingTypeTableBuilder() = default;
  33
  34 std::optional<TypeIndex> MergingTypeTableBuilder::getFirst() {
  35   if (empty())
  36     return std::nullopt;
  37
  38   return TypeIndex(TypeIndex::FirstNonSimpleIndex);
  39 }
  40
  41 std::optional<TypeIndex> MergingTypeTableBuilder::getNext(TypeIndex Prev) {
  42   if (++Prev == nextTypeIndex())
  43     return std::nullopt;
  44   return Prev;
  45 }
  46
  47 CVType MergingTypeTableBuilder::getType(TypeIndex Index) {
  48   CVType Type(SeenRecords[Index.toArrayIndex()]);
  49   return Type;
  50 }
  51
  52 StringRef MergingTypeTableBuilder::getTypeName(TypeIndex Index) {
  53   llvm_unreachable("Method not implemented");
  54 }
  55
  56 bool MergingTypeTableBuilder::contains(TypeIndex Index) {
  57   if (Index.isSimple() || Index.isNoneType())
  58     return false;
  59
  60   return Index.toArrayIndex() < SeenRecords.size();
  61 }
  62
  63 uint32_t MergingTypeTableBuilder::size() { return SeenRecords.size(); }
  64
  65 uint32_t MergingTypeTableBuilder::capacity() { return SeenRecords.size(); }
  66
  67 ArrayRef<ArrayRef<uint8_t>> MergingTypeTableBuilder::records() const {
  68   return SeenRecords;
  69 }
  70
  71 void MergingTypeTableBuilder::reset() {
  72   HashedRecords.clear();
  73   SeenRecords.clear();
  74 }
  75
  76 static inline ArrayRef<uint8_t> stabilize(BumpPtrAllocator &Alloc,
  77                                           ArrayRef<uint8_t> Data) {
  78   uint8_t *Stable = Alloc.Allocate<uint8_t>(Data.size());
  79   memcpy(Stable, Data.data(), Data.size());
  80   return ArrayRef(Stable, Data.size());
  81 }
  82
  83 TypeIndex MergingTypeTableBuilder::insertRecordAs(hash_code Hash,
  84                                                   ArrayRef<uint8_t> &Record) {
  85   assert(Record.size() < UINT32_MAX && "Record too big");
  86   assert(Record.size() % 4 == 0 &&
  87          "The type record size is not a multiple of 4 bytes which will cause "
  88          "misalignment in the output TPI stream!");
  89
  90   LocallyHashedType WeakHash{Hash, Record};
  91   auto Result = HashedRecords.try_emplace(WeakHash, nextTypeIndex());
  92
  93   if (Result.second) {
  94     ArrayRef<uint8_t> RecordData = stabilize(RecordStorage, Record);
  95     Result.first->first.RecordData = RecordData;
  96     SeenRecords.push_back(RecordData);
  97   }
  98
  99   // Update the caller's copy of Record to point a stable copy.
 100   TypeIndex ActualTI = Result.first->second;
 101   Record = SeenRecords[ActualTI.toArrayIndex()];
 102   return ActualTI;
 103 }
 104
 105 TypeIndex
 106 MergingTypeTableBuilder::insertRecordBytes(ArrayRef<uint8_t> &Record) {
 107   return insertRecordAs(hash_value(Record), Record);
 108 }
 109
 110 TypeIndex
 111 MergingTypeTableBuilder::insertRecord(ContinuationRecordBuilder &Builder) {
 112   TypeIndex TI;
 113   auto Fragments = Builder.end(nextTypeIndex());
 114   assert(!Fragments.empty());
 115   for (auto C : Fragments)
 116     TI = insertRecordBytes(C.RecordData);
 117   return TI;
 118 }
 119
 120 bool MergingTypeTableBuilder::replaceType(TypeIndex &Index, CVType Data,
 121                                           bool Stabilize) {
 122   assert(Index.toArrayIndex() < SeenRecords.size() &&
 123          "This function cannot be used to insert records!");
 124
 125   ArrayRef<uint8_t> Record = Data.data();
 126   assert(Record.size() < UINT32_MAX && "Record too big");
 127   assert(Record.size() % 4 == 0 &&
 128          "The type record size is not a multiple of 4 bytes which will cause "
 129          "misalignment in the output TPI stream!");
 130
 131   LocallyHashedType WeakHash{hash_value(Record), Record};
 132   auto Result = HashedRecords.try_emplace(WeakHash, Index.toArrayIndex());
 133   if (!Result.second) {
 134     Index = Result.first->second;
 135     return false; // The record is already there, at a different location
 136   }
 137
 138   if (Stabilize) {
 139     Record = stabilize(RecordStorage, Record);
 140     Result.first->first.RecordData = Record;
 141   }
 142
 143   SeenRecords[Index.toArrayIndex()] = Record;
 144   return true;
 145 }