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 "DWARFDebugArangeSet.h"
11 #include "llvm/Support/Format.h"
12 #include "llvm/Support/raw_ostream.h"
13 #include <algorithm>
14 #include <cassert>
15 using namespace llvm;
16
clear()17 void DWARFDebugArangeSet::clear() {
18 Offset = -1U;
19 std::memset(&Header, 0, sizeof(Header));
20 ArangeDescriptors.clear();
21 }
22
compact()23 void DWARFDebugArangeSet::compact() {
24 if (ArangeDescriptors.empty())
25 return;
26
27 // Iterate through all arange descriptors and combine any ranges that
28 // overlap or have matching boundaries. The ArangeDescriptors are assumed
29 // to be in ascending order.
30 uint32_t i = 0;
31 while (i + 1 < ArangeDescriptors.size()) {
32 if (ArangeDescriptors[i].getEndAddress() >= ArangeDescriptors[i+1].Address){
33 // The current range ends at or exceeds the start of the next address
34 // range. Compute the max end address between the two and use that to
35 // make the new length.
36 const uint64_t max_end_addr =
37 std::max(ArangeDescriptors[i].getEndAddress(),
38 ArangeDescriptors[i+1].getEndAddress());
39 ArangeDescriptors[i].Length = max_end_addr - ArangeDescriptors[i].Address;
40 // Now remove the next entry as it was just combined with the previous one
41 ArangeDescriptors.erase(ArangeDescriptors.begin()+i+1);
42 } else {
43 // Discontiguous address range, just proceed to the next one.
44 ++i;
45 }
46 }
47 }
48
49 bool
extract(DataExtractor data,uint32_t * offset_ptr)50 DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) {
51 if (data.isValidOffset(*offset_ptr)) {
52 ArangeDescriptors.clear();
53 Offset = *offset_ptr;
54
55 // 7.20 Address Range Table
56 //
57 // Each set of entries in the table of address ranges contained in
58 // the .debug_aranges section begins with a header consisting of: a
59 // 4-byte length containing the length of the set of entries for this
60 // compilation unit, not including the length field itself; a 2-byte
61 // version identifier containing the value 2 for DWARF Version 2; a
62 // 4-byte offset into the.debug_infosection; a 1-byte unsigned integer
63 // containing the size in bytes of an address (or the offset portion of
64 // an address for segmented addressing) on the target system; and a
65 // 1-byte unsigned integer containing the size in bytes of a segment
66 // descriptor on the target system. This header is followed by a series
67 // of tuples. Each tuple consists of an address and a length, each in
68 // the size appropriate for an address on the target architecture.
69 Header.Length = data.getU32(offset_ptr);
70 Header.Version = data.getU16(offset_ptr);
71 Header.CuOffset = data.getU32(offset_ptr);
72 Header.AddrSize = data.getU8(offset_ptr);
73 Header.SegSize = data.getU8(offset_ptr);
74
75 // Perform basic validation of the header fields.
76 if (!data.isValidOffsetForDataOfSize(Offset, Header.Length) ||
77 (Header.AddrSize != 4 && Header.AddrSize != 8)) {
78 clear();
79 return false;
80 }
81
82 // The first tuple following the header in each set begins at an offset
83 // that is a multiple of the size of a single tuple (that is, twice the
84 // size of an address). The header is padded, if necessary, to the
85 // appropriate boundary.
86 const uint32_t header_size = *offset_ptr - Offset;
87 const uint32_t tuple_size = Header.AddrSize * 2;
88 uint32_t first_tuple_offset = 0;
89 while (first_tuple_offset < header_size)
90 first_tuple_offset += tuple_size;
91
92 *offset_ptr = Offset + first_tuple_offset;
93
94 Descriptor arangeDescriptor;
95
96 assert(sizeof(arangeDescriptor.Address) == sizeof(arangeDescriptor.Length));
97 assert(sizeof(arangeDescriptor.Address) >= Header.AddrSize);
98
99 while (data.isValidOffset(*offset_ptr)) {
100 arangeDescriptor.Address = data.getUnsigned(offset_ptr, Header.AddrSize);
101 arangeDescriptor.Length = data.getUnsigned(offset_ptr, Header.AddrSize);
102
103 // Each set of tuples is terminated by a 0 for the address and 0
104 // for the length.
105 if (arangeDescriptor.Address || arangeDescriptor.Length)
106 ArangeDescriptors.push_back(arangeDescriptor);
107 else
108 break; // We are done if we get a zero address and length
109 }
110
111 return !ArangeDescriptors.empty();
112 }
113 return false;
114 }
115
dump(raw_ostream & OS) const116 void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
117 OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
118 Header.Length, Header.Version)
119 << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
120 Header.CuOffset, Header.AddrSize, Header.SegSize);
121
122 const uint32_t hex_width = Header.AddrSize * 2;
123 for (DescriptorConstIter pos = ArangeDescriptors.begin(),
124 end = ArangeDescriptors.end(); pos != end; ++pos)
125 OS << format("[0x%*.*llx -", hex_width, hex_width, pos->Address)
126 << format(" 0x%*.*llx)\n", hex_width, hex_width, pos->getEndAddress());
127 }
128
129
130 namespace {
131 class DescriptorContainsAddress {
132 const uint64_t Address;
133 public:
DescriptorContainsAddress(uint64_t address)134 DescriptorContainsAddress(uint64_t address) : Address(address) {}
operator ()(const DWARFDebugArangeSet::Descriptor & desc) const135 bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const {
136 return Address >= desc.Address && Address < (desc.Address + desc.Length);
137 }
138 };
139 }
140
findAddress(uint64_t address) const141 uint32_t DWARFDebugArangeSet::findAddress(uint64_t address) const {
142 DescriptorConstIter end = ArangeDescriptors.end();
143 DescriptorConstIter pos =
144 std::find_if(ArangeDescriptors.begin(), end, // Range
145 DescriptorContainsAddress(address)); // Predicate
146 if (pos != end)
147 return Header.CuOffset;
148
149 return -1U;
150 }
151