DWARFDebugArangeSet.cpp revision 360784 
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/Support/Format.h"
11#include "llvm/Support/raw_ostream.h"
12#include <cassert>
13#include <cinttypes>
14#include <cstdint>
15#include <cstring>
16
17using namespace llvm;
18
19void DWARFDebugArangeSet::Descriptor::dump(raw_ostream &OS,
20                                           uint32_t AddressSize) const {
21  OS << format("[0x%*.*" PRIx64 ", ", AddressSize * 2, AddressSize * 2, Address)
22     << format(" 0x%*.*" PRIx64 ")", AddressSize * 2, AddressSize * 2,
23               getEndAddress());
24}
25
26void DWARFDebugArangeSet::clear() {
27  Offset = -1ULL;
28  std::memset(&HeaderData, 0, sizeof(Header));
29  ArangeDescriptors.clear();
30}
31
32bool
33DWARFDebugArangeSet::extract(DataExtractor data, uint64_t *offset_ptr) {
34  if (data.isValidOffset(*offset_ptr)) {
35    ArangeDescriptors.clear();
36    Offset = *offset_ptr;
37
38    // 7.20 Address Range Table
39    //
40    // Each set of entries in the table of address ranges contained in
41    // the .debug_aranges section begins with a header consisting of: a
42    // 4-byte length containing the length of the set of entries for this
43    // compilation unit, not including the length field itself; a 2-byte
44    // version identifier containing the value 2 for DWARF Version 2; a
45    // 4-byte offset into the.debug_infosection; a 1-byte unsigned integer
46    // containing the size in bytes of an address (or the offset portion of
47    // an address for segmented addressing) on the target system; and a
48    // 1-byte unsigned integer containing the size in bytes of a segment
49    // descriptor on the target system. This header is followed by a series
50    // of tuples. Each tuple consists of an address and a length, each in
51    // the size appropriate for an address on the target architecture.
52    HeaderData.Length = data.getU32(offset_ptr);
53    HeaderData.Version = data.getU16(offset_ptr);
54    HeaderData.CuOffset = data.getU32(offset_ptr);
55    HeaderData.AddrSize = data.getU8(offset_ptr);
56    HeaderData.SegSize = data.getU8(offset_ptr);
57
58    // Perform basic validation of the header fields.
59    if (!data.isValidOffsetForDataOfSize(Offset, HeaderData.Length) ||
60        (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)) {
61      clear();
62      return false;
63    }
64
65    // The first tuple following the header in each set begins at an offset
66    // that is a multiple of the size of a single tuple (that is, twice the
67    // size of an address). The header is padded, if necessary, to the
68    // appropriate boundary.
69    const uint32_t header_size = *offset_ptr - Offset;
70    const uint32_t tuple_size = HeaderData.AddrSize * 2;
71    uint32_t first_tuple_offset = 0;
72    while (first_tuple_offset < header_size)
73      first_tuple_offset += tuple_size;
74
75    *offset_ptr = Offset + first_tuple_offset;
76
77    Descriptor arangeDescriptor;
78
79    static_assert(sizeof(arangeDescriptor.Address) ==
80                      sizeof(arangeDescriptor.Length),
81                  "Different datatypes for addresses and sizes!");
82    assert(sizeof(arangeDescriptor.Address) >= HeaderData.AddrSize);
83
84    while (data.isValidOffset(*offset_ptr)) {
85      arangeDescriptor.Address = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
86      arangeDescriptor.Length = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
87
88      // Each set of tuples is terminated by a 0 for the address and 0
89      // for the length.
90      if (arangeDescriptor.Address || arangeDescriptor.Length)
91        ArangeDescriptors.push_back(arangeDescriptor);
92      else
93        break; // We are done if we get a zero address and length
94    }
95
96    return !ArangeDescriptors.empty();
97  }
98  return false;
99}
100
101void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
102  OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
103               HeaderData.Length, HeaderData.Version)
104     << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
105               HeaderData.CuOffset, HeaderData.AddrSize, HeaderData.SegSize);
106
107  for (const auto &Desc : ArangeDescriptors) {
108    Desc.dump(OS, HeaderData.AddrSize);
109    OS << '\n';
110  }
111}
112