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