1//===-- DWARFDebugAranges.cpp -----------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10#include "DWARFDebugAranges.h" 11#include "DWARFCompileUnit.h" 12#include "DWARFContext.h" 13#include "DWARFDebugArangeSet.h" 14#include "llvm/Support/Format.h" 15#include "llvm/Support/raw_ostream.h" 16#include <algorithm> 17#include <cassert> 18#include <set> 19using namespace llvm; 20 21void DWARFDebugAranges::extract(DataExtractor DebugArangesData) { 22 if (!DebugArangesData.isValidOffset(0)) 23 return; 24 uint32_t Offset = 0; 25 DWARFDebugArangeSet Set; 26 27 while (Set.extract(DebugArangesData, &Offset)) { 28 uint32_t CUOffset = Set.getCompileUnitDIEOffset(); 29 for (const auto &Desc : Set.descriptors()) { 30 uint64_t LowPC = Desc.Address; 31 uint64_t HighPC = Desc.getEndAddress(); 32 appendRange(CUOffset, LowPC, HighPC); 33 } 34 ParsedCUOffsets.insert(CUOffset); 35 } 36} 37 38void DWARFDebugAranges::generate(DWARFContext *CTX) { 39 clear(); 40 if (!CTX) 41 return; 42 43 // Extract aranges from .debug_aranges section. 44 DataExtractor ArangesData(CTX->getARangeSection(), CTX->isLittleEndian(), 0); 45 extract(ArangesData); 46 47 // Generate aranges from DIEs: even if .debug_aranges section is present, 48 // it may describe only a small subset of compilation units, so we need to 49 // manually build aranges for the rest of them. 50 for (const auto &CU : CTX->compile_units()) { 51 uint32_t CUOffset = CU->getOffset(); 52 if (ParsedCUOffsets.insert(CUOffset).second) { 53 DWARFAddressRangesVector CURanges; 54 CU->collectAddressRanges(CURanges); 55 for (const auto &R : CURanges) { 56 appendRange(CUOffset, R.first, R.second); 57 } 58 } 59 } 60 61 construct(); 62} 63 64void DWARFDebugAranges::clear() { 65 Endpoints.clear(); 66 Aranges.clear(); 67 ParsedCUOffsets.clear(); 68} 69 70void DWARFDebugAranges::appendRange(uint32_t CUOffset, uint64_t LowPC, 71 uint64_t HighPC) { 72 if (LowPC >= HighPC) 73 return; 74 Endpoints.emplace_back(LowPC, CUOffset, true); 75 Endpoints.emplace_back(HighPC, CUOffset, false); 76} 77 78void DWARFDebugAranges::construct() { 79 std::multiset<uint32_t> ValidCUs; // Maintain the set of CUs describing 80 // a current address range. 81 std::sort(Endpoints.begin(), Endpoints.end()); 82 uint64_t PrevAddress = -1ULL; 83 for (const auto &E : Endpoints) { 84 if (PrevAddress < E.Address && ValidCUs.size() > 0) { 85 // If the address range between two endpoints is described by some 86 // CU, first try to extend the last range in Aranges. If we can't 87 // do it, start a new range. 88 if (!Aranges.empty() && Aranges.back().HighPC() == PrevAddress && 89 ValidCUs.find(Aranges.back().CUOffset) != ValidCUs.end()) { 90 Aranges.back().setHighPC(E.Address); 91 } else { 92 Aranges.emplace_back(PrevAddress, E.Address, *ValidCUs.begin()); 93 } 94 } 95 // Update the set of valid CUs. 96 if (E.IsRangeStart) { 97 ValidCUs.insert(E.CUOffset); 98 } else { 99 auto CUPos = ValidCUs.find(E.CUOffset); 100 assert(CUPos != ValidCUs.end()); 101 ValidCUs.erase(CUPos); 102 } 103 PrevAddress = E.Address; 104 } 105 assert(ValidCUs.empty()); 106 107 // Endpoints are not needed now. 108 std::vector<RangeEndpoint> EmptyEndpoints; 109 EmptyEndpoints.swap(Endpoints); 110} 111 112uint32_t DWARFDebugAranges::findAddress(uint64_t Address) const { 113 if (!Aranges.empty()) { 114 Range range(Address); 115 RangeCollIterator begin = Aranges.begin(); 116 RangeCollIterator end = Aranges.end(); 117 RangeCollIterator pos = 118 std::lower_bound(begin, end, range); 119 120 if (pos != end && pos->containsAddress(Address)) { 121 return pos->CUOffset; 122 } else if (pos != begin) { 123 --pos; 124 if (pos->containsAddress(Address)) 125 return pos->CUOffset; 126 } 127 } 128 return -1U; 129} 130