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comparison: toolkit/crashreporter/google-breakpad/src/common/dwarf/cfi_assembler.cc

toolkit/crashreporter/google-breakpad/src/common/dwarf/cfi_assembler.cc

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TOR_BUG_3246
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-1:000000000000 0:e1304e32583b
1 // Copyright (c) 2010, Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
13 // distribution.
14 // * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
31
32 // cfi_assembler.cc: Implementation of google_breakpad::CFISection class.
33 // See cfi_assembler.h for details.
34
35 #include "common/dwarf/cfi_assembler.h"
36
37 #include <assert.h>
38 #include <stdlib.h>
39
40 namespace google_breakpad {
41
42 using dwarf2reader::DwarfPointerEncoding;
43
44 CFISection &CFISection::CIEHeader(uint64_t code_alignment_factor,
45 int data_alignment_factor,
46 unsigned return_address_register,
47 uint8_t version,
48 const string &augmentation,
49 bool dwarf64) {
50 assert(!entry_length_);
51 entry_length_ = new PendingLength();
52 in_fde_ = false;
53
54 if (dwarf64) {
55 D32(kDwarf64InitialLengthMarker);
56 D64(entry_length_->length);
57 entry_length_->start = Here();
58 D64(eh_frame_ ? kEHFrame64CIEIdentifier : kDwarf64CIEIdentifier);
59 } else {
60 D32(entry_length_->length);
61 entry_length_->start = Here();
62 D32(eh_frame_ ? kEHFrame32CIEIdentifier : kDwarf32CIEIdentifier);
63 }
64 D8(version);
65 AppendCString(augmentation);
66 ULEB128(code_alignment_factor);
67 LEB128(data_alignment_factor);
68 if (version == 1)
69 D8(return_address_register);
70 else
71 ULEB128(return_address_register);
72 return *this;
73 }
74
75 CFISection &CFISection::FDEHeader(Label cie_pointer,
76 uint64_t initial_location,
77 uint64_t address_range,
78 bool dwarf64) {
79 assert(!entry_length_);
80 entry_length_ = new PendingLength();
81 in_fde_ = true;
82 fde_start_address_ = initial_location;
83
84 if (dwarf64) {
85 D32(0xffffffff);
86 D64(entry_length_->length);
87 entry_length_->start = Here();
88 if (eh_frame_)
89 D64(Here() - cie_pointer);
90 else
91 D64(cie_pointer);
92 } else {
93 D32(entry_length_->length);
94 entry_length_->start = Here();
95 if (eh_frame_)
96 D32(Here() - cie_pointer);
97 else
98 D32(cie_pointer);
99 }
100 EncodedPointer(initial_location);
101 // The FDE length in an .eh_frame section uses the same encoding as the
102 // initial location, but ignores the base address (selected by the upper
103 // nybble of the encoding), as it's a length, not an address that can be
104 // made relative.
105 EncodedPointer(address_range,
106 DwarfPointerEncoding(pointer_encoding_ & 0x0f));
107 return *this;
108 }
109
110 CFISection &CFISection::FinishEntry() {
111 assert(entry_length_);
112 Align(address_size_, dwarf2reader::DW_CFA_nop);
113 entry_length_->length = Here() - entry_length_->start;
114 delete entry_length_;
115 entry_length_ = NULL;
116 in_fde_ = false;
117 return *this;
118 }
119
120 CFISection &CFISection::EncodedPointer(uint64_t address,
121 DwarfPointerEncoding encoding,
122 const EncodedPointerBases &bases) {
123 // Omitted data is extremely easy to emit.
124 if (encoding == dwarf2reader::DW_EH_PE_omit)
125 return *this;
126
127 // If (encoding & dwarf2reader::DW_EH_PE_indirect) != 0, then we assume
128 // that ADDRESS is the address at which the pointer is stored --- in
129 // other words, that bit has no effect on how we write the pointer.
130 encoding = DwarfPointerEncoding(encoding & ~dwarf2reader::DW_EH_PE_indirect);
131
132 // Find the base address to which this pointer is relative. The upper
133 // nybble of the encoding specifies this.
134 uint64_t base;
135 switch (encoding & 0xf0) {
136 case dwarf2reader::DW_EH_PE_absptr: base = 0; break;
137 case dwarf2reader::DW_EH_PE_pcrel: base = bases.cfi + Size(); break;
138 case dwarf2reader::DW_EH_PE_textrel: base = bases.text; break;
139 case dwarf2reader::DW_EH_PE_datarel: base = bases.data; break;
140 case dwarf2reader::DW_EH_PE_funcrel: base = fde_start_address_; break;
141 case dwarf2reader::DW_EH_PE_aligned: base = 0; break;
142 default: abort();
143 };
144
145 // Make ADDRESS relative. Yes, this is appropriate even for "absptr"
146 // values; see gcc/unwind-pe.h.
147 address -= base;
148
149 // Align the pointer, if required.
150 if ((encoding & 0xf0) == dwarf2reader::DW_EH_PE_aligned)
151 Align(AddressSize());
152
153 // Append ADDRESS to this section in the appropriate form. For the
154 // fixed-width forms, we don't need to differentiate between signed and
155 // unsigned encodings, because ADDRESS has already been extended to 64
156 // bits before it was passed to us.
157 switch (encoding & 0x0f) {
158 case dwarf2reader::DW_EH_PE_absptr:
159 Address(address);
160 break;
161
162 case dwarf2reader::DW_EH_PE_uleb128:
163 ULEB128(address);
164 break;
165
166 case dwarf2reader::DW_EH_PE_sleb128:
167 LEB128(address);
168 break;
169
170 case dwarf2reader::DW_EH_PE_udata2:
171 case dwarf2reader::DW_EH_PE_sdata2:
172 D16(address);
173 break;
174
175 case dwarf2reader::DW_EH_PE_udata4:
176 case dwarf2reader::DW_EH_PE_sdata4:
177 D32(address);
178 break;
179
180 case dwarf2reader::DW_EH_PE_udata8:
181 case dwarf2reader::DW_EH_PE_sdata8:
182 D64(address);
183 break;
184
185 default:
186 abort();
187 }
188
189 return *this;
190 };
191
192 const uint32_t CFISection::kDwarf64InitialLengthMarker;
193 const uint32_t CFISection::kDwarf32CIEIdentifier;
194 const uint64_t CFISection::kDwarf64CIEIdentifier;
195 const uint32_t CFISection::kEHFrame32CIEIdentifier;
196 const uint64_t CFISection::kEHFrame64CIEIdentifier;
197
198 } // namespace google_breakpad

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