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/DWARFAddressRange.h" 11 #include "llvm/DebugInfo/DWARF/DWARFContext.h" 12 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h" 13 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h" 14 #include "llvm/DebugInfo/DWARF/DWARFObject.h" 15 #include "llvm/DebugInfo/DWARF/DWARFUnit.h" 16 #include <algorithm> 17 #include <cassert> 18 #include <cstdint> 19 #include <set> 20 21 using namespace llvm; 22 23 void DWARFDebugAranges::extract( 24 DWARFDataExtractor DebugArangesData, 25 function_ref<void(Error)> RecoverableErrorHandler, 26 function_ref<void(Error)> WarningHandler) { 27 if (!DebugArangesData.isValidOffset(0)) 28 return; 29 uint64_t Offset = 0; 30 DWARFDebugArangeSet Set; 31 32 while (DebugArangesData.isValidOffset(Offset)) { 33 if (Error E = Set.extract(DebugArangesData, &Offset, WarningHandler)) { 34 RecoverableErrorHandler(std::move(E)); 35 return; 36 } 37 uint64_t CUOffset = Set.getCompileUnitDIEOffset(); 38 for (const auto &Desc : Set.descriptors()) { 39 uint64_t LowPC = Desc.Address; 40 uint64_t HighPC = Desc.getEndAddress(); 41 appendRange(CUOffset, LowPC, HighPC); 42 } 43 ParsedCUOffsets.insert(CUOffset); 44 } 45 } 46 47 void DWARFDebugAranges::generate(DWARFContext *CTX) { 48 clear(); 49 if (!CTX) 50 return; 51 52 // Extract aranges from .debug_aranges section. 53 DWARFDataExtractor ArangesData(CTX->getDWARFObj().getArangesSection(), 54 CTX->isLittleEndian(), 0); 55 extract(ArangesData, CTX->getRecoverableErrorHandler(), 56 CTX->getWarningHandler()); 57 58 // Generate aranges from DIEs: even if .debug_aranges section is present, 59 // it may describe only a small subset of compilation units, so we need to 60 // manually build aranges for the rest of them. 61 for (const auto &CU : CTX->compile_units()) { 62 uint64_t CUOffset = CU->getOffset(); 63 if (ParsedCUOffsets.insert(CUOffset).second) { 64 Expected<DWARFAddressRangesVector> CURanges = CU->collectAddressRanges(); 65 if (!CURanges) 66 CTX->getRecoverableErrorHandler()(CURanges.takeError()); 67 else 68 for (const auto &R : *CURanges) 69 appendRange(CUOffset, R.LowPC, R.HighPC); 70 } 71 } 72 73 construct(); 74 } 75 76 void DWARFDebugAranges::clear() { 77 Endpoints.clear(); 78 Aranges.clear(); 79 ParsedCUOffsets.clear(); 80 } 81 82 void DWARFDebugAranges::appendRange(uint64_t CUOffset, uint64_t LowPC, 83 uint64_t HighPC) { 84 if (LowPC >= HighPC) 85 return; 86 Endpoints.emplace_back(LowPC, CUOffset, true); 87 Endpoints.emplace_back(HighPC, CUOffset, false); 88 } 89 90 void DWARFDebugAranges::construct() { 91 std::multiset<uint64_t> ValidCUs; // Maintain the set of CUs describing 92 // a current address range. 93 llvm::sort(Endpoints); 94 uint64_t PrevAddress = -1ULL; 95 for (const auto &E : Endpoints) { 96 if (PrevAddress < E.Address && !ValidCUs.empty()) { 97 // If the address range between two endpoints is described by some 98 // CU, first try to extend the last range in Aranges. If we can't 99 // do it, start a new range. 100 if (!Aranges.empty() && Aranges.back().HighPC() == PrevAddress && 101 ValidCUs.find(Aranges.back().CUOffset) != ValidCUs.end()) { 102 Aranges.back().setHighPC(E.Address); 103 } else { 104 Aranges.emplace_back(PrevAddress, E.Address, *ValidCUs.begin()); 105 } 106 } 107 // Update the set of valid CUs. 108 if (E.IsRangeStart) { 109 ValidCUs.insert(E.CUOffset); 110 } else { 111 auto CUPos = ValidCUs.find(E.CUOffset); 112 assert(CUPos != ValidCUs.end()); 113 ValidCUs.erase(CUPos); 114 } 115 PrevAddress = E.Address; 116 } 117 assert(ValidCUs.empty()); 118 119 // Endpoints are not needed now. 120 Endpoints.clear(); 121 Endpoints.shrink_to_fit(); 122 } 123 124 uint64_t DWARFDebugAranges::findAddress(uint64_t Address) const { 125 RangeCollIterator It = 126 partition_point(Aranges, [=](Range R) { return R.HighPC() <= Address; }); 127 if (It != Aranges.end() && It->LowPC <= Address) 128 return It->CUOffset; 129 return -1ULL; 130 } 131