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 "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
11 #include "llvm/Support/Format.h"
12 #include "llvm/Support/raw_ostream.h"
13 #include <cassert>
14 #include <cinttypes>
15 #include <cstdint>
16 #include <cstring>
17 
18 using namespace llvm;
19 
20 void DWARFDebugArangeSet::Descriptor::dump(raw_ostream &OS,
21                                            uint32_t AddressSize) const {
22   OS << format("[0x%*.*" PRIx64 ", ", AddressSize * 2, AddressSize * 2, Address)
23      << format(" 0x%*.*" PRIx64 ")", AddressSize * 2, AddressSize * 2,
24                getEndAddress());
25 }
26 
27 void DWARFDebugArangeSet::clear() {
28   Offset = -1U;
29   std::memset(&HeaderData, 0, sizeof(Header));
30   ArangeDescriptors.clear();
31 }
32 
33 bool
34 DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) {
35   if (data.isValidOffset(*offset_ptr)) {
36     ArangeDescriptors.clear();
37     Offset = *offset_ptr;
38 
39     // 7.20 Address Range Table
40     //
41     // Each set of entries in the table of address ranges contained in
42     // the .debug_aranges section begins with a header consisting of: a
43     // 4-byte length containing the length of the set of entries for this
44     // compilation unit, not including the length field itself; a 2-byte
45     // version identifier containing the value 2 for DWARF Version 2; a
46     // 4-byte offset into the.debug_infosection; a 1-byte unsigned integer
47     // containing the size in bytes of an address (or the offset portion of
48     // an address for segmented addressing) on the target system; and a
49     // 1-byte unsigned integer containing the size in bytes of a segment
50     // descriptor on the target system. This header is followed by a series
51     // of tuples. Each tuple consists of an address and a length, each in
52     // the size appropriate for an address on the target architecture.
53     HeaderData.Length = data.getU32(offset_ptr);
54     HeaderData.Version = data.getU16(offset_ptr);
55     HeaderData.CuOffset = data.getU32(offset_ptr);
56     HeaderData.AddrSize = data.getU8(offset_ptr);
57     HeaderData.SegSize = data.getU8(offset_ptr);
58 
59     // Perform basic validation of the header fields.
60     if (!data.isValidOffsetForDataOfSize(Offset, HeaderData.Length) ||
61         (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)) {
62       clear();
63       return false;
64     }
65 
66     // The first tuple following the header in each set begins at an offset
67     // that is a multiple of the size of a single tuple (that is, twice the
68     // size of an address). The header is padded, if necessary, to the
69     // appropriate boundary.
70     const uint32_t header_size = *offset_ptr - Offset;
71     const uint32_t tuple_size = HeaderData.AddrSize * 2;
72     uint32_t first_tuple_offset = 0;
73     while (first_tuple_offset < header_size)
74       first_tuple_offset += tuple_size;
75 
76     *offset_ptr = Offset + first_tuple_offset;
77 
78     Descriptor arangeDescriptor;
79 
80     static_assert(sizeof(arangeDescriptor.Address) ==
81                       sizeof(arangeDescriptor.Length),
82                   "Different datatypes for addresses and sizes!");
83     assert(sizeof(arangeDescriptor.Address) >= HeaderData.AddrSize);
84 
85     while (data.isValidOffset(*offset_ptr)) {
86       arangeDescriptor.Address = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
87       arangeDescriptor.Length = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
88 
89       // Each set of tuples is terminated by a 0 for the address and 0
90       // for the length.
91       if (arangeDescriptor.Address || arangeDescriptor.Length)
92         ArangeDescriptors.push_back(arangeDescriptor);
93       else
94         break; // We are done if we get a zero address and length
95     }
96 
97     return !ArangeDescriptors.empty();
98   }
99   return false;
100 }
101 
102 void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
103   OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
104                HeaderData.Length, HeaderData.Version)
105      << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
106                HeaderData.CuOffset, HeaderData.AddrSize, HeaderData.SegSize);
107 
108   for (const auto &Desc : ArangeDescriptors) {
109     Desc.dump(OS, HeaderData.AddrSize);
110     OS << '\n';
111   }
112 }
113