DWARFDebugArangeSet.cpp revision 341825
1//===-- DWARFDebugArangeSet.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 "DWARFDebugArangeSet.h" 11 12#include "SymbolFileDWARF.h" 13#include "lldb/Utility/Stream.h" 14#include <assert.h> 15 16using namespace lldb_private; 17 18DWARFDebugArangeSet::DWARFDebugArangeSet() 19 : m_offset(DW_INVALID_OFFSET), m_header(), m_arange_descriptors() { 20 m_header.length = 0; 21 m_header.version = 0; 22 m_header.cu_offset = 0; 23 m_header.addr_size = 0; 24 m_header.seg_size = 0; 25} 26 27void DWARFDebugArangeSet::Clear() { 28 m_offset = DW_INVALID_OFFSET; 29 m_header.length = 0; 30 m_header.version = 0; 31 m_header.cu_offset = 0; 32 m_header.addr_size = 0; 33 m_header.seg_size = 0; 34 m_arange_descriptors.clear(); 35} 36 37void DWARFDebugArangeSet::SetHeader(uint16_t version, uint32_t cu_offset, 38 uint8_t addr_size, uint8_t seg_size) { 39 m_header.version = version; 40 m_header.cu_offset = cu_offset; 41 m_header.addr_size = addr_size; 42 m_header.seg_size = seg_size; 43} 44 45void DWARFDebugArangeSet::Compact() { 46 if (m_arange_descriptors.empty()) 47 return; 48 49 // Iterate through all arange descriptors and combine any ranges that overlap 50 // or have matching boundaries. The m_arange_descriptors are assumed to be in 51 // ascending order after being built by adding descriptors using the 52 // AddDescriptor method. 53 uint32_t i = 0; 54 while (i + 1 < m_arange_descriptors.size()) { 55 if (m_arange_descriptors[i].end_address() >= 56 m_arange_descriptors[i + 1].address) { 57 // The current range ends at or exceeds the start of the next address 58 // range. Compute the max end address between the two and use that to 59 // make the new length. 60 const dw_addr_t max_end_addr = 61 std::max(m_arange_descriptors[i].end_address(), 62 m_arange_descriptors[i + 1].end_address()); 63 m_arange_descriptors[i].length = 64 max_end_addr - m_arange_descriptors[i].address; 65 // Now remove the next entry as it was just combined with the previous 66 // one. 67 m_arange_descriptors.erase(m_arange_descriptors.begin() + i + 1); 68 } else { 69 // Discontiguous address range, just proceed to the next one. 70 ++i; 71 } 72 } 73} 74//---------------------------------------------------------------------- 75// Compare function DWARFDebugArangeSet::Descriptor structures 76//---------------------------------------------------------------------- 77static bool DescriptorLessThan(const DWARFDebugArangeSet::Descriptor &range1, 78 const DWARFDebugArangeSet::Descriptor &range2) { 79 return range1.address < range2.address; 80} 81 82//---------------------------------------------------------------------- 83// Add a range descriptor and keep things sorted so we can easily compact the 84// ranges before being saved or used. 85//---------------------------------------------------------------------- 86void DWARFDebugArangeSet::AddDescriptor( 87 const DWARFDebugArangeSet::Descriptor &range) { 88 if (m_arange_descriptors.empty()) { 89 m_arange_descriptors.push_back(range); 90 return; 91 } 92 93 DescriptorIter end = m_arange_descriptors.end(); 94 DescriptorIter pos = 95 lower_bound(m_arange_descriptors.begin(), end, range, DescriptorLessThan); 96 const dw_addr_t range_end_addr = range.end_address(); 97 if (pos != end) { 98 const dw_addr_t found_end_addr = pos->end_address(); 99 if (range.address < pos->address) { 100 if (range_end_addr < pos->address) { 101 // Non-contiguous entries, add this one before the found entry 102 m_arange_descriptors.insert(pos, range); 103 } else if (range_end_addr == pos->address) { 104 // The top end of 'range' is the lower end of the entry pointed to by 105 // 'pos'. We can combine range with the entry we found by setting the 106 // starting address and increasing the length since they don't overlap. 107 pos->address = range.address; 108 pos->length += range.length; 109 } else { 110 // We can combine these two and make sure the largest end address is 111 // used to make end address. 112 pos->address = range.address; 113 pos->length = std::max(found_end_addr, range_end_addr) - pos->address; 114 } 115 } else if (range.address == pos->address) { 116 pos->length = std::max(pos->length, range.length); 117 } 118 } else { 119 // NOTE: 'pos' points to entry past the end which is ok for insert, 120 // don't use otherwise!!! 121 const dw_addr_t max_addr = m_arange_descriptors.back().end_address(); 122 if (max_addr < range.address) { 123 // Non-contiguous entries, add this one before the found entry 124 m_arange_descriptors.insert(pos, range); 125 } else if (max_addr == range.address) { 126 m_arange_descriptors.back().length += range.length; 127 } else { 128 m_arange_descriptors.back().length = std::max(max_addr, range_end_addr) - 129 m_arange_descriptors.back().address; 130 } 131 } 132} 133 134bool DWARFDebugArangeSet::Extract(const DWARFDataExtractor &data, 135 lldb::offset_t *offset_ptr) { 136 if (data.ValidOffset(*offset_ptr)) { 137 m_arange_descriptors.clear(); 138 m_offset = *offset_ptr; 139 140 // 7.20 Address Range Table 141 // 142 // Each set of entries in the table of address ranges contained in the 143 // .debug_aranges section begins with a header consisting of: a 4-byte 144 // length containing the length of the set of entries for this compilation 145 // unit, not including the length field itself; a 2-byte version identifier 146 // containing the value 2 for DWARF Version 2; a 4-byte offset into 147 // the.debug_infosection; a 1-byte unsigned integer containing the size in 148 // bytes of an address (or the offset portion of an address for segmented 149 // addressing) on the target system; and a 1-byte unsigned integer 150 // containing the size in bytes of a segment descriptor on the target 151 // system. This header is followed by a series of tuples. Each tuple 152 // consists of an address and a length, each in the size appropriate for an 153 // address on the target architecture. 154 m_header.length = data.GetDWARFInitialLength(offset_ptr); 155 m_header.version = data.GetU16(offset_ptr); 156 m_header.cu_offset = data.GetDWARFOffset(offset_ptr); 157 m_header.addr_size = data.GetU8(offset_ptr); 158 m_header.seg_size = data.GetU8(offset_ptr); 159 160 // Try to avoid reading invalid arange sets by making sure: 161 // 1 - the version looks good 162 // 2 - the address byte size looks plausible 163 // 3 - the length seems to make sense 164 // size looks plausible 165 if ((m_header.version >= 2 && m_header.version <= 5) && 166 (m_header.addr_size == 4 || m_header.addr_size == 8) && 167 (m_header.length > 0)) { 168 if (data.ValidOffset(m_offset + sizeof(m_header.length) + 169 m_header.length - 1)) { 170 // The first tuple following the header in each set begins at an offset 171 // that is a multiple of the size of a single tuple (that is, twice the 172 // size of an address). The header is padded, if necessary, to the 173 // appropriate boundary. 174 const uint32_t header_size = *offset_ptr - m_offset; 175 const uint32_t tuple_size = m_header.addr_size << 1; 176 uint32_t first_tuple_offset = 0; 177 while (first_tuple_offset < header_size) 178 first_tuple_offset += tuple_size; 179 180 *offset_ptr = m_offset + first_tuple_offset; 181 182 Descriptor arangeDescriptor; 183 184 static_assert( 185 sizeof(arangeDescriptor.address) == sizeof(arangeDescriptor.length), 186 "DWARFDebugArangeSet::Descriptor.address and " 187 "DWARFDebugArangeSet::Descriptor.length must have same size"); 188 189 while (data.ValidOffset(*offset_ptr)) { 190 arangeDescriptor.address = 191 data.GetMaxU64(offset_ptr, m_header.addr_size); 192 arangeDescriptor.length = 193 data.GetMaxU64(offset_ptr, m_header.addr_size); 194 195 // Each set of tuples is terminated by a 0 for the address and 0 for 196 // the length. 197 if (arangeDescriptor.address || arangeDescriptor.length) 198 m_arange_descriptors.push_back(arangeDescriptor); 199 else 200 break; // We are done if we get a zero address and length 201 } 202 } 203#if defined(LLDB_CONFIGURATION_DEBUG) 204 else { 205 printf("warning: .debug_arange set length is too large arange data at " 206 "0x%8.8x: length=0x%8.8x, version=0x%4.4x, cu_offset=0x%8.8x, " 207 "addr_size=%u, seg_size=%u\n", 208 m_offset, m_header.length, m_header.version, m_header.cu_offset, 209 m_header.addr_size, m_header.seg_size); 210 } 211#endif 212 } 213#if defined(LLDB_CONFIGURATION_DEBUG) 214 else { 215 printf("warning: .debug_arange set has bad header at 0x%8.8x: " 216 "length=0x%8.8x, version=0x%4.4x, cu_offset=0x%8.8x, " 217 "addr_size=%u, seg_size=%u\n", 218 m_offset, m_header.length, m_header.version, m_header.cu_offset, 219 m_header.addr_size, m_header.seg_size); 220 } 221#endif 222 223 return !m_arange_descriptors.empty(); 224 } 225 return false; 226} 227 228dw_offset_t DWARFDebugArangeSet::GetOffsetOfNextEntry() const { 229 return m_offset + m_header.length + 4; 230} 231 232void DWARFDebugArangeSet::Dump(Stream *s) const { 233 s->Printf("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, " 234 "cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n", 235 m_header.length, m_header.version, m_header.cu_offset, 236 m_header.addr_size, m_header.seg_size); 237 238 const uint32_t hex_width = m_header.addr_size * 2; 239 DescriptorConstIter pos; 240 DescriptorConstIter end = m_arange_descriptors.end(); 241 for (pos = m_arange_descriptors.begin(); pos != end; ++pos) 242 s->Printf("[0x%*.*" PRIx64 " - 0x%*.*" PRIx64 ")\n", hex_width, hex_width, 243 pos->address, hex_width, hex_width, pos->end_address()); 244} 245 246class DescriptorContainsAddress { 247public: 248 DescriptorContainsAddress(dw_addr_t address) : m_address(address) {} 249 bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const { 250 return (m_address >= desc.address) && 251 (m_address < (desc.address + desc.length)); 252 } 253 254private: 255 const dw_addr_t m_address; 256}; 257 258dw_offset_t DWARFDebugArangeSet::FindAddress(dw_addr_t address) const { 259 DescriptorConstIter end = m_arange_descriptors.end(); 260 DescriptorConstIter pos = 261 std::find_if(m_arange_descriptors.begin(), end, // Range 262 DescriptorContainsAddress(address)); // Predicate 263 if (pos != end) 264 return m_header.cu_offset; 265 266 return DW_INVALID_OFFSET; 267} 268