1 //===- DWARFDebugAranges.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/DWARF/DWARFDebugAranges.h" 10 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h" 11 #include "llvm/DebugInfo/DWARF/DWARFContext.h" 12 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h" 13 #include "llvm/Support/DataExtractor.h" 14 #include "llvm/Support/WithColor.h" 15 #include <algorithm> 16 #include <cassert> 17 #include <cstdint> 18 #include <set> 19 #include <vector> 20 21 using namespace llvm; 22 23 void DWARFDebugAranges::extract(DataExtractor DebugArangesData) { 24 if (!DebugArangesData.isValidOffset(0)) 25 return; 26 uint64_t Offset = 0; 27 DWARFDebugArangeSet Set; 28 29 while (Set.extract(DebugArangesData, &Offset)) { 30 uint64_t CUOffset = Set.getCompileUnitDIEOffset(); 31 for (const auto &Desc : Set.descriptors()) { 32 uint64_t LowPC = Desc.Address; 33 uint64_t HighPC = Desc.getEndAddress(); 34 appendRange(CUOffset, LowPC, HighPC); 35 } 36 ParsedCUOffsets.insert(CUOffset); 37 } 38 } 39 40 void DWARFDebugAranges::generate(DWARFContext *CTX) { 41 clear(); 42 if (!CTX) 43 return; 44 45 // Extract aranges from .debug_aranges section. 46 DataExtractor ArangesData(CTX->getDWARFObj().getArangesSection(), 47 CTX->isLittleEndian(), 0); 48 extract(ArangesData); 49 50 // Generate aranges from DIEs: even if .debug_aranges section is present, 51 // it may describe only a small subset of compilation units, so we need to 52 // manually build aranges for the rest of them. 53 for (const auto &CU : CTX->compile_units()) { 54 uint64_t CUOffset = CU->getOffset(); 55 if (ParsedCUOffsets.insert(CUOffset).second) { 56 Expected<DWARFAddressRangesVector> CURanges = CU->collectAddressRanges(); 57 if (!CURanges) 58 WithColor::error() << toString(CURanges.takeError()) << '\n'; 59 else 60 for (const auto &R : *CURanges) 61 appendRange(CUOffset, R.LowPC, R.HighPC); 62 } 63 } 64 65 construct(); 66 } 67 68 void DWARFDebugAranges::clear() { 69 Endpoints.clear(); 70 Aranges.clear(); 71 ParsedCUOffsets.clear(); 72 } 73 74 void DWARFDebugAranges::appendRange(uint64_t CUOffset, uint64_t LowPC, 75 uint64_t HighPC) { 76 if (LowPC >= HighPC) 77 return; 78 Endpoints.emplace_back(LowPC, CUOffset, true); 79 Endpoints.emplace_back(HighPC, CUOffset, false); 80 } 81 82 void DWARFDebugAranges::construct() { 83 std::multiset<uint64_t> ValidCUs; // Maintain the set of CUs describing 84 // a current address range. 85 llvm::sort(Endpoints); 86 uint64_t PrevAddress = -1ULL; 87 for (const auto &E : Endpoints) { 88 if (PrevAddress < E.Address && !ValidCUs.empty()) { 89 // If the address range between two endpoints is described by some 90 // CU, first try to extend the last range in Aranges. If we can't 91 // do it, start a new range. 92 if (!Aranges.empty() && Aranges.back().HighPC() == PrevAddress && 93 ValidCUs.find(Aranges.back().CUOffset) != ValidCUs.end()) { 94 Aranges.back().setHighPC(E.Address); 95 } else { 96 Aranges.emplace_back(PrevAddress, E.Address, *ValidCUs.begin()); 97 } 98 } 99 // Update the set of valid CUs. 100 if (E.IsRangeStart) { 101 ValidCUs.insert(E.CUOffset); 102 } else { 103 auto CUPos = ValidCUs.find(E.CUOffset); 104 assert(CUPos != ValidCUs.end()); 105 ValidCUs.erase(CUPos); 106 } 107 PrevAddress = E.Address; 108 } 109 assert(ValidCUs.empty()); 110 111 // Endpoints are not needed now. 112 Endpoints.clear(); 113 Endpoints.shrink_to_fit(); 114 } 115 116 uint64_t DWARFDebugAranges::findAddress(uint64_t Address) const { 117 RangeCollIterator It = 118 partition_point(Aranges, [=](Range R) { return R.HighPC() <= Address; }); 119 if (It != Aranges.end() && It->LowPC <= Address) 120 return It->CUOffset; 121 return -1ULL; 122 } 123