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