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