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