llvm/lib/DebugInfo/DWARF/DWARFDebugArangeSet.cpp

   1 //===- DWARFDebugArangeSet.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/DWARFDebugArangeSet.h"
  10 #include "llvm/BinaryFormat/Dwarf.h"
  11 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  12 #include "llvm/Support/Errc.h"
  13 #include "llvm/Support/Format.h"
  14 #include "llvm/Support/raw_ostream.h"
  15 #include <cassert>
  16 #include <cinttypes>
  17 #include <cstdint>
  18 #include <cstring>
  19
  20 using namespace llvm;
  21
  22 void DWARFDebugArangeSet::Descriptor::dump(raw_ostream &OS,
  23                                            uint32_t AddressSize) const {
  24   OS << '[';
  25   DWARFFormValue::dumpAddress(OS, AddressSize, Address);
  26   OS << ", ";
  27   DWARFFormValue::dumpAddress(OS, AddressSize, getEndAddress());
  28   OS << ')';
  29 }
  30
  31 void DWARFDebugArangeSet::clear() {
  32   Offset = -1ULL;
  33   std::memset(&HeaderData, 0, sizeof(Header));
  34   ArangeDescriptors.clear();
  35 }
  36
  37 Error DWARFDebugArangeSet::extract(DWARFDataExtractor data,
  38                                    uint64_t *offset_ptr,
  39                                    function_ref<void(Error)> WarningHandler) {
  40   assert(data.isValidOffset(*offset_ptr));
  41   ArangeDescriptors.clear();
  42   Offset = *offset_ptr;
  43
  44   // 7.21 Address Range Table (extract)
  45   // Each set of entries in the table of address ranges contained in
  46   // the .debug_aranges section begins with a header containing:
  47   // 1. unit_length (initial length)
  48   //    A 4-byte (32-bit DWARF) or 12-byte (64-bit DWARF) length containing
  49   //    the length of the set of entries for this compilation unit,
  50   //    not including the length field itself.
  51   // 2. version (uhalf)
  52   //    The value in this field is 2.
  53   // 3. debug_info_offset (section offset)
  54   //    A 4-byte (32-bit DWARF) or 8-byte (64-bit DWARF) offset into the
  55   //    .debug_info section of the compilation unit header.
  56   // 4. address_size (ubyte)
  57   // 5. segment_selector_size (ubyte)
  58   // This header is followed by a series of tuples. Each tuple consists of
  59   // a segment, an address and a length. The segment selector size is given by
  60   // the segment_selector_size field of the header; the address and length
  61   // size are each given by the address_size field of the header. Each set of
  62   // tuples is terminated by a 0 for the segment, a 0 for the address and 0
  63   // for the length. If the segment_selector_size field in the header is zero,
  64   // the segment selectors are omitted from all tuples, including
  65   // the terminating tuple.
  66
  67   Error Err = Error::success();
  68   std::tie(HeaderData.Length, HeaderData.Format) =
  69       data.getInitialLength(offset_ptr, &Err);
  70   HeaderData.Version = data.getU16(offset_ptr, &Err);
  71   HeaderData.CuOffset = data.getUnsigned(
  72       offset_ptr, dwarf::getDwarfOffsetByteSize(HeaderData.Format), &Err);
  73   HeaderData.AddrSize = data.getU8(offset_ptr, &Err);
  74   HeaderData.SegSize = data.getU8(offset_ptr, &Err);
  75   if (Err) {
  76     return createStringError(errc::invalid_argument,
  77                              "parsing address ranges table at offset 0x%" PRIx64
  78                              ": %s",
  79                              Offset, toString(std::move(Err)).c_str());
  80   }
  81
  82   // Perform basic validation of the header fields.
  83   uint64_t full_length =
  84       dwarf::getUnitLengthFieldByteSize(HeaderData.Format) + HeaderData.Length;
  85   if (!data.isValidOffsetForDataOfSize(Offset, full_length))
  86     return createStringError(errc::invalid_argument,
  87                              "the length of address range table at offset "
  88                              "0x%" PRIx64 " exceeds section size",
  89                              Offset);
  90   if (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)
  91     return createStringError(errc::invalid_argument,
  92                              "address range table at offset 0x%" PRIx64
  93                              " has unsupported address size: %d "
  94                              "(4 and 8 supported)",
  95                              Offset, HeaderData.AddrSize);
  96   if (HeaderData.SegSize != 0)
  97     return createStringError(errc::not_supported,
  98                              "non-zero segment selector size in address range "
  99                              "table at offset 0x%" PRIx64 " is not supported",
 100                              Offset);
 101
 102   // The first tuple following the header in each set begins at an offset that
 103   // is a multiple of the size of a single tuple (that is, twice the size of
 104   // an address because we do not support non-zero segment selector sizes).
 105   // Therefore, the full length should also be a multiple of the tuple size.
 106   const uint32_t tuple_size = HeaderData.AddrSize * 2;
 107   if (full_length % tuple_size != 0)
 108     return createStringError(
 109         errc::invalid_argument,
 110         "address range table at offset 0x%" PRIx64
 111         " has length that is not a multiple of the tuple size",
 112         Offset);
 113
 114   // The header is padded, if necessary, to the appropriate boundary.
 115   const uint32_t header_size = *offset_ptr - Offset;
 116   uint32_t first_tuple_offset = 0;
 117   while (first_tuple_offset < header_size)
 118     first_tuple_offset += tuple_size;
 119
 120   // There should be space for at least one tuple.
 121   if (full_length <= first_tuple_offset)
 122     return createStringError(
 123         errc::invalid_argument,
 124         "address range table at offset 0x%" PRIx64
 125         " has an insufficient length to contain any entries",
 126         Offset);
 127
 128   *offset_ptr = Offset + first_tuple_offset;
 129
 130   Descriptor arangeDescriptor;
 131
 132   static_assert(sizeof(arangeDescriptor.Address) ==
 133                     sizeof(arangeDescriptor.Length),
 134                 "Different datatypes for addresses and sizes!");
 135   assert(sizeof(arangeDescriptor.Address) >= HeaderData.AddrSize);
 136
 137   uint64_t end_offset = Offset + full_length;
 138   while (*offset_ptr < end_offset) {
 139     uint64_t EntryOffset = *offset_ptr;
 140     arangeDescriptor.Address = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
 141     arangeDescriptor.Length = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
 142
 143     // Each set of tuples is terminated by a 0 for the address and 0
 144     // for the length.
 145     if (arangeDescriptor.Length == 0 && arangeDescriptor.Address == 0) {
 146       if (*offset_ptr == end_offset)
 147         return ErrorSuccess();
 148       WarningHandler(createStringError(
 149           errc::invalid_argument,
 150           "address range table at offset 0x%" PRIx64
 151           " has a premature terminator entry at offset 0x%" PRIx64,
 152           Offset, EntryOffset));
 153     }
 154
 155     ArangeDescriptors.push_back(arangeDescriptor);
 156   }
 157
 158   return createStringError(errc::invalid_argument,
 159                            "address range table at offset 0x%" PRIx64
 160                            " is not terminated by null entry",
 161                            Offset);
 162 }
 163
 164 void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
 165   int OffsetDumpWidth = 2 * dwarf::getDwarfOffsetByteSize(HeaderData.Format);
 166   OS << "Address Range Header: "
 167      << format("length = 0x%0*" PRIx64 ", ", OffsetDumpWidth, HeaderData.Length)
 168      << "format = " << dwarf::FormatString(HeaderData.Format) << ", "
 169      << format("version = 0x%4.4x, ", HeaderData.Version)
 170      << format("cu_offset = 0x%0*" PRIx64 ", ", OffsetDumpWidth,
 171                HeaderData.CuOffset)
 172      << format("addr_size = 0x%2.2x, ", HeaderData.AddrSize)
 173      << format("seg_size = 0x%2.2x\n", HeaderData.SegSize);
 174
 175   for (const auto &Desc : ArangeDescriptors) {
 176     Desc.dump(OS, HeaderData.AddrSize);
 177     OS << '\n';
 178   }
 179 }