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
|
// Copyright (c) 2010, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
// cfi_assembler.cc: Implementation of google_breakpad::CFISection class.
// See cfi_assembler.h for details.
#include <cassert>
#include <stdlib.h>
#include "common/dwarf/cfi_assembler.h"
namespace google_breakpad {
using dwarf2reader::DwarfPointerEncoding;
CFISection &CFISection::CIEHeader(u_int64_t code_alignment_factor,
int data_alignment_factor,
unsigned return_address_register,
u_int8_t version,
const string &augmentation,
bool dwarf64) {
assert(!entry_length_);
entry_length_ = new PendingLength();
in_fde_ = false;
if (dwarf64) {
D32(0xffffffff);
D64(entry_length_->length);
entry_length_->start = Here();
// Write the CIE distinguished value. In .debug_frame sections, it's
// ~0; in .eh_frame sections, it's zero.
D64(eh_frame_ ? 0 : ~(u_int64_t)0);
} else {
D32(entry_length_->length);
entry_length_->start = Here();
// Write the CIE distinguished value. In .debug_frame sections, it's
// ~0; in .eh_frame sections, it's zero.
D32(eh_frame_ ? 0 : ~(u_int32_t)0);
}
D8(version);
AppendCString(augmentation);
ULEB128(code_alignment_factor);
LEB128(data_alignment_factor);
if (version == 1)
D8(return_address_register);
else
ULEB128(return_address_register);
return *this;
}
CFISection &CFISection::FDEHeader(Label cie_pointer,
u_int64_t initial_location,
u_int64_t address_range,
bool dwarf64) {
assert(!entry_length_);
entry_length_ = new PendingLength();
in_fde_ = true;
fde_start_address_ = initial_location;
if (dwarf64) {
D32(0xffffffff);
D64(entry_length_->length);
entry_length_->start = Here();
if (eh_frame_)
D64(Here() - cie_pointer);
else
D64(cie_pointer);
} else {
D32(entry_length_->length);
entry_length_->start = Here();
if (eh_frame_)
D32(Here() - cie_pointer);
else
D32(cie_pointer);
}
EncodedPointer(initial_location);
// The FDE length in an .eh_frame section uses the same encoding as the
// initial location, but ignores the base address (selected by the upper
// nybble of the encoding), as it's a length, not an address that can be
// made relative.
EncodedPointer(address_range,
DwarfPointerEncoding(pointer_encoding_ & 0x0f));
return *this;
}
CFISection &CFISection::FinishEntry() {
assert(entry_length_);
Align(address_size_, dwarf2reader::DW_CFA_nop);
entry_length_->length = Here() - entry_length_->start;
delete entry_length_;
entry_length_ = NULL;
in_fde_ = false;
return *this;
}
CFISection &CFISection::EncodedPointer(u_int64_t address,
DwarfPointerEncoding encoding,
const EncodedPointerBases &bases) {
// Omitted data is extremely easy to emit.
if (encoding == dwarf2reader::DW_EH_PE_omit)
return *this;
// If (encoding & dwarf2reader::DW_EH_PE_indirect) != 0, then we assume
// that ADDRESS is the address at which the pointer is stored --- in
// other words, that bit has no effect on how we write the pointer.
encoding = DwarfPointerEncoding(encoding & ~dwarf2reader::DW_EH_PE_indirect);
// Find the base address to which this pointer is relative. The upper
// nybble of the encoding specifies this.
u_int64_t base;
switch (encoding & 0xf0) {
case dwarf2reader::DW_EH_PE_absptr: base = 0; break;
case dwarf2reader::DW_EH_PE_pcrel: base = bases.cfi + Size(); break;
case dwarf2reader::DW_EH_PE_textrel: base = bases.text; break;
case dwarf2reader::DW_EH_PE_datarel: base = bases.data; break;
case dwarf2reader::DW_EH_PE_funcrel: base = fde_start_address_; break;
case dwarf2reader::DW_EH_PE_aligned: base = 0; break;
default: abort();
};
// Make ADDRESS relative. Yes, this is appropriate even for "absptr"
// values; see gcc/unwind-pe.h.
address -= base;
// Align the pointer, if required.
if ((encoding & 0xf0) == dwarf2reader::DW_EH_PE_aligned)
Align(AddressSize());
// Append ADDRESS to this section in the appropriate form. For the
// fixed-width forms, we don't need to differentiate between signed and
// unsigned encodings, because ADDRESS has already been extended to 64
// bits before it was passed to us.
switch (encoding & 0x0f) {
case dwarf2reader::DW_EH_PE_absptr:
Address(address);
break;
case dwarf2reader::DW_EH_PE_uleb128:
ULEB128(address);
break;
case dwarf2reader::DW_EH_PE_sleb128:
LEB128(address);
break;
case dwarf2reader::DW_EH_PE_udata2:
case dwarf2reader::DW_EH_PE_sdata2:
D16(address);
break;
case dwarf2reader::DW_EH_PE_udata4:
case dwarf2reader::DW_EH_PE_sdata4:
D32(address);
break;
case dwarf2reader::DW_EH_PE_udata8:
case dwarf2reader::DW_EH_PE_sdata8:
D64(address);
break;
default:
abort();
}
return *this;
};
} // namespace google_breakpad
|
