1 //===-- DWARFDebugArangeSet.cpp -------------------------------------------===// 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 "DWARFDebugArangeSet.h" 11 #include "llvm/Support/Format.h" 12 #include "llvm/Support/raw_ostream.h" 13 #include <algorithm> 14 #include <cassert> 15 using namespace llvm; 16 17 void DWARFDebugArangeSet::clear() { 18 Offset = -1U; 19 std::memset(&Header, 0, sizeof(Header)); 20 ArangeDescriptors.clear(); 21 } 22 23 void DWARFDebugArangeSet::compact() { 24 if (ArangeDescriptors.empty()) 25 return; 26 27 // Iterate through all arange descriptors and combine any ranges that 28 // overlap or have matching boundaries. The ArangeDescriptors are assumed 29 // to be in ascending order. 30 uint32_t i = 0; 31 while (i + 1 < ArangeDescriptors.size()) { 32 if (ArangeDescriptors[i].getEndAddress() >= ArangeDescriptors[i+1].Address){ 33 // The current range ends at or exceeds the start of the next address 34 // range. Compute the max end address between the two and use that to 35 // make the new length. 36 const uint64_t max_end_addr = 37 std::max(ArangeDescriptors[i].getEndAddress(), 38 ArangeDescriptors[i+1].getEndAddress()); 39 ArangeDescriptors[i].Length = max_end_addr - ArangeDescriptors[i].Address; 40 // Now remove the next entry as it was just combined with the previous one 41 ArangeDescriptors.erase(ArangeDescriptors.begin()+i+1); 42 } else { 43 // Discontiguous address range, just proceed to the next one. 44 ++i; 45 } 46 } 47 } 48 49 bool 50 DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) { 51 if (data.isValidOffset(*offset_ptr)) { 52 ArangeDescriptors.clear(); 53 Offset = *offset_ptr; 54 55 // 7.20 Address Range Table 56 // 57 // Each set of entries in the table of address ranges contained in 58 // the .debug_aranges section begins with a header consisting of: a 59 // 4-byte length containing the length of the set of entries for this 60 // compilation unit, not including the length field itself; a 2-byte 61 // version identifier containing the value 2 for DWARF Version 2; a 62 // 4-byte offset into the.debug_infosection; a 1-byte unsigned integer 63 // containing the size in bytes of an address (or the offset portion of 64 // an address for segmented addressing) on the target system; and a 65 // 1-byte unsigned integer containing the size in bytes of a segment 66 // descriptor on the target system. This header is followed by a series 67 // of tuples. Each tuple consists of an address and a length, each in 68 // the size appropriate for an address on the target architecture. 69 Header.Length = data.getU32(offset_ptr); 70 Header.Version = data.getU16(offset_ptr); 71 Header.CuOffset = data.getU32(offset_ptr); 72 Header.AddrSize = data.getU8(offset_ptr); 73 Header.SegSize = data.getU8(offset_ptr); 74 75 // Perform basic validation of the header fields. 76 if (!data.isValidOffsetForDataOfSize(Offset, Header.Length) || 77 (Header.AddrSize != 4 && Header.AddrSize != 8)) { 78 clear(); 79 return false; 80 } 81 82 // The first tuple following the header in each set begins at an offset 83 // that is a multiple of the size of a single tuple (that is, twice the 84 // size of an address). The header is padded, if necessary, to the 85 // appropriate boundary. 86 const uint32_t header_size = *offset_ptr - Offset; 87 const uint32_t tuple_size = Header.AddrSize * 2; 88 uint32_t first_tuple_offset = 0; 89 while (first_tuple_offset < header_size) 90 first_tuple_offset += tuple_size; 91 92 *offset_ptr = Offset + first_tuple_offset; 93 94 Descriptor arangeDescriptor; 95 96 assert(sizeof(arangeDescriptor.Address) == sizeof(arangeDescriptor.Length)); 97 assert(sizeof(arangeDescriptor.Address) >= Header.AddrSize); 98 99 while (data.isValidOffset(*offset_ptr)) { 100 arangeDescriptor.Address = data.getUnsigned(offset_ptr, Header.AddrSize); 101 arangeDescriptor.Length = data.getUnsigned(offset_ptr, Header.AddrSize); 102 103 // Each set of tuples is terminated by a 0 for the address and 0 104 // for the length. 105 if (arangeDescriptor.Address || arangeDescriptor.Length) 106 ArangeDescriptors.push_back(arangeDescriptor); 107 else 108 break; // We are done if we get a zero address and length 109 } 110 111 return !ArangeDescriptors.empty(); 112 } 113 return false; 114 } 115 116 void DWARFDebugArangeSet::dump(raw_ostream &OS) const { 117 OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ", 118 Header.Length, Header.Version) 119 << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n", 120 Header.CuOffset, Header.AddrSize, Header.SegSize); 121 122 const uint32_t hex_width = Header.AddrSize * 2; 123 for (DescriptorConstIter pos = ArangeDescriptors.begin(), 124 end = ArangeDescriptors.end(); pos != end; ++pos) 125 OS << format("[0x%*.*llx -", hex_width, hex_width, pos->Address) 126 << format(" 0x%*.*llx)\n", hex_width, hex_width, pos->getEndAddress()); 127 } 128 129 130 namespace { 131 class DescriptorContainsAddress { 132 const uint64_t Address; 133 public: 134 DescriptorContainsAddress(uint64_t address) : Address(address) {} 135 bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const { 136 return Address >= desc.Address && Address < (desc.Address + desc.Length); 137 } 138 }; 139 } 140 141 uint32_t DWARFDebugArangeSet::findAddress(uint64_t address) const { 142 DescriptorConstIter end = ArangeDescriptors.end(); 143 DescriptorConstIter pos = 144 std::find_if(ArangeDescriptors.begin(), end, // Range 145 DescriptorContainsAddress(address)); // Predicate 146 if (pos != end) 147 return Header.CuOffset; 148 149 return -1U; 150 } 151
