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/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
  21 using namespace llvm;
  22 using namespace llvm::codeview;
  23
  24 TypeIndex MergingTypeTableBuilder::nextTypeIndex() const {
  25   return TypeIndex::fromArrayIndex(SeenRecords.size());
  26 }
  27
  28 MergingTypeTableBuilder::MergingTypeTableBuilder(BumpPtrAllocator &Storage)
  29     : RecordStorage(Storage) {
  30   SeenRecords.reserve(4096);
  31 }
  32
  33 MergingTypeTableBuilder::~MergingTypeTableBuilder() = default;
  34
  35 std::optional<TypeIndex> MergingTypeTableBuilder::getFirst() {
  36   if (empty())
  37     return std::nullopt;
  38
  39   return TypeIndex(TypeIndex::FirstNonSimpleIndex);
  40 }
  41
  42 std::optional<TypeIndex> MergingTypeTableBuilder::getNext(TypeIndex Prev) {
  43   if (++Prev == nextTypeIndex())
  44     return std::nullopt;
  45   return Prev;
  46 }
  47
  48 CVType MergingTypeTableBuilder::getType(TypeIndex Index) {
  49   CVType Type(SeenRecords[Index.toArrayIndex()]);
  50   return Type;
  51 }
  52
  53 StringRef MergingTypeTableBuilder::getTypeName(TypeIndex Index) {
  54   llvm_unreachable("Method not implemented");
  55 }
  56
  57 bool MergingTypeTableBuilder::contains(TypeIndex Index) {
  58   if (Index.isSimple() || Index.isNoneType())
  59     return false;
  60
  61   return Index.toArrayIndex() < SeenRecords.size();
  62 }
  63
  64 uint32_t MergingTypeTableBuilder::size() { return SeenRecords.size(); }
  65
  66 uint32_t MergingTypeTableBuilder::capacity() { return SeenRecords.size(); }
  67
  68 ArrayRef<ArrayRef<uint8_t>> MergingTypeTableBuilder::records() const {
  69   return SeenRecords;
  70 }
  71
  72 void MergingTypeTableBuilder::reset() {
  73   HashedRecords.clear();
  74   SeenRecords.clear();
  75 }
  76
  77 static 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
  84 TypeIndex 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
 106 TypeIndex
 107 MergingTypeTableBuilder::insertRecordBytes(ArrayRef<uint8_t> &Record) {
 108   return insertRecordAs(hash_value(Record), Record);
 109 }
 110
 111 TypeIndex
 112 MergingTypeTableBuilder::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
 121 bool 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 }