1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
// Copyright (c) 2013 Austin T. Clements. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
#include "internal.hh"
using namespace std;
DWARFPP_BEGIN_NAMESPACE
die::die(const unit *cu)
: cu(cu), abbrev(nullptr)
{
}
const unit &
die::get_unit() const
{
return *cu;
}
section_offset
die::get_section_offset() const
{
return cu->get_section_offset() + offset;
}
void
die::read(section_offset off)
{
cursor cur(cu->data(), off);
offset = off;
abbrev_code acode = cur.uleb128();
if (acode == 0) {
abbrev = nullptr;
next = cur.get_section_offset();
return;
}
abbrev = &cu->get_abbrev(acode);
tag = abbrev->tag;
// XXX We can pre-compute almost all of this work in the
// abbrev_entry.
attrs.clear();
attrs.reserve(abbrev->attributes.size());
for (auto &attr : abbrev->attributes) {
attrs.push_back(cur.get_section_offset());
cur.skip_form(attr.form);
}
next = cur.get_section_offset();
}
bool
die::has(DW_AT attr) const
{
if (!abbrev)
return false;
// XXX Totally lame
for (auto &a : abbrev->attributes)
if (a.name == attr)
return true;
return false;
}
value
die::operator[](DW_AT attr) const
{
// XXX We can pre-compute almost all of this work in the
// abbrev_entry.
if (abbrev) {
int i = 0;
for (auto &a : abbrev->attributes) {
if (a.name == attr)
return value(cu, a.name, a.form, a.type, attrs[i]);
i++;
}
}
throw out_of_range("DIE does not have attribute " + to_string(attr));
}
value
die::resolve(DW_AT attr) const
{
// DWARF4 section 2.13, DWARF4 section 3.3.8
// DWARF4 is unclear about what to do when there's both a
// DW_AT::specification and a DW_AT::abstract_origin.
// Conceptually, though, a concrete inlined instance cannot
// itself complete an external function that wasn't first
// completed by its abstract instance, so we first try to
// resolve abstract_origin, then we resolve specification.
// XXX This traverses the abbrevs at least twice and
// potentially several more times
if (has(attr))
return (*this)[attr];
if (has(DW_AT::abstract_origin)) {
die ao = (*this)[DW_AT::abstract_origin].as_reference();
if (ao.has(attr))
return ao[attr];
if (ao.has(DW_AT::specification)) {
die s = ao[DW_AT::specification].as_reference();
if (s.has(attr))
return s[attr];
}
} else if (has(DW_AT::specification)) {
die s = (*this)[DW_AT::specification].as_reference();
if (s.has(attr))
return s[attr];
}
return value();
}
die::iterator
die::begin() const
{
if (!abbrev || !abbrev->children)
return end();
return iterator(cu, next);
}
die::iterator::iterator(const unit *cu, section_offset off)
: d(cu)
{
d.read(off);
}
die::iterator &
die::iterator::operator++()
{
if (!d.abbrev)
return *this;
if (!d.abbrev->children) {
// The DIE has no children, so its successor follows
// immediately
d.read(d.next);
} else if (d.has(DW_AT::sibling)) {
// They made it easy on us. Follow the sibling
// pointer. XXX Probably worth optimizing
d = d[DW_AT::sibling].as_reference();
} else {
// It's a hard-knock life. We have to iterate through
// the children to find the next DIE.
// XXX Particularly unfortunate if the user is doing a
// DFS, since this will result in N^2 behavior. Maybe
// a small cache of terminator locations in the CU?
iterator sub(d.cu, d.next);
while (sub->abbrev)
++sub;
d.read(sub->next);
}
return *this;
}
const vector<pair<DW_AT, value> >
die::attributes() const
{
vector<pair<DW_AT, value> > res;
if (!abbrev)
return res;
// XXX Quite slow, especially when using this to traverse an
// entire DIE tree since each DIE will produce a new vector
// (whereas other vectors get reused). Might be worth a
// custom iterator.
int i = 0;
for (auto &a : abbrev->attributes) {
res.push_back(make_pair(a.name, value(cu, a.name, a.form, a.type, attrs[i])));
i++;
}
return res;
}
bool
die::operator==(const die &o) const
{
return cu == o.cu && offset == o.offset;
}
bool
die::operator!=(const die &o) const
{
return !(*this == o);
}
DWARFPP_END_NAMESPACE
size_t
std::hash<dwarf::die>::operator()(const dwarf::die &a) const
{
return hash<decltype(a.cu)>()(a.cu) ^
hash<decltype(a.get_unit_offset())>()(a.get_unit_offset());
}
|
