jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include "LineProgram.h"
8#include <AK/Debug.h>
9#include <AK/DeprecatedString.h>
10#include <AK/Function.h>
11#include <AK/LEB128.h>
12#include <AK/StringBuilder.h>
13#include <LibDebug/Dwarf/DwarfInfo.h>
14
15namespace Debug::Dwarf {
16
17LineProgram::LineProgram(DwarfInfo& dwarf_info, SeekableStream& stream)
18 : m_dwarf_info(dwarf_info)
19 , m_stream(stream)
20{
21 m_unit_offset = m_stream.tell().release_value_but_fixme_should_propagate_errors();
22 parse_unit_header().release_value_but_fixme_should_propagate_errors();
23 parse_source_directories().release_value_but_fixme_should_propagate_errors();
24 parse_source_files().release_value_but_fixme_should_propagate_errors();
25 run_program().release_value_but_fixme_should_propagate_errors();
26}
27
28ErrorOr<void> LineProgram::parse_unit_header()
29{
30 m_unit_header = TRY(m_stream.read_value<LineProgramUnitHeader32>());
31
32 VERIFY(m_unit_header.version() >= MIN_DWARF_VERSION && m_unit_header.version() <= MAX_DWARF_VERSION);
33 VERIFY(m_unit_header.opcode_base() <= sizeof(m_unit_header.std_opcode_lengths) / sizeof(m_unit_header.std_opcode_lengths[0]) + 1);
34
35 dbgln_if(DWARF_DEBUG, "unit length: {}", m_unit_header.length());
36 return {};
37}
38
39ErrorOr<void> LineProgram::parse_path_entries(Function<void(PathEntry& entry)> callback, PathListType list_type)
40{
41 if (m_unit_header.version() >= 5) {
42 auto path_entry_format_count = TRY(m_stream.read_value<u8>());
43
44 Vector<PathEntryFormat> format_descriptions;
45
46 for (u8 i = 0; i < path_entry_format_count; i++) {
47 UnderlyingType<ContentType> content_type = TRY(m_stream.read_value<LEB128<UnderlyingType<ContentType>>>());
48
49 UnderlyingType<AttributeDataForm> data_form = TRY(m_stream.read_value<LEB128<UnderlyingType<AttributeDataForm>>>());
50
51 format_descriptions.empend(static_cast<ContentType>(content_type), static_cast<AttributeDataForm>(data_form));
52 }
53
54 size_t paths_count = TRY(m_stream.read_value<LEB128<size_t>>());
55
56 for (size_t i = 0; i < paths_count; i++) {
57 PathEntry entry;
58 for (auto& format_description : format_descriptions) {
59 auto value = TRY(m_dwarf_info.get_attribute_value(format_description.form, 0, m_stream));
60 switch (format_description.type) {
61 case ContentType::Path:
62 entry.path = TRY(value.as_string());
63 break;
64 case ContentType::DirectoryIndex:
65 entry.directory_index = value.as_unsigned();
66 break;
67 default:
68 dbgln_if(DWARF_DEBUG, "Unhandled path list attribute: {}", to_underlying(format_description.type));
69 }
70 }
71 callback(entry);
72 }
73 } else {
74 while (true) {
75 StringBuilder builder;
76 while (auto c = TRY(m_stream.read_value<char>()))
77 TRY(builder.try_append(c));
78 auto path = builder.to_deprecated_string();
79 if (path.length() == 0)
80 break;
81 dbgln_if(DWARF_DEBUG, "path: {}", path);
82 PathEntry entry;
83 entry.path = path;
84 if (list_type == PathListType::Filenames) {
85 size_t directory_index = TRY(m_stream.read_value<LEB128<size_t>>());
86 TRY(m_stream.read_value<LEB128<size_t>>()); // skip modification time
87 TRY(m_stream.read_value<LEB128<size_t>>()); // skip file size
88 entry.directory_index = directory_index;
89 dbgln_if(DWARF_DEBUG, "file: {}, directory index: {}", path, directory_index);
90 }
91 callback(entry);
92 }
93 }
94
95 return {};
96}
97
98ErrorOr<void> LineProgram::parse_source_directories()
99{
100 if (m_unit_header.version() < 5) {
101 m_source_directories.append(".");
102 }
103
104 TRY(parse_path_entries([this](PathEntry& entry) {
105 m_source_directories.append(entry.path);
106 },
107 PathListType::Directories));
108
109 return {};
110}
111
112ErrorOr<void> LineProgram::parse_source_files()
113{
114 if (m_unit_header.version() < 5) {
115 m_source_files.append({ ".", 0 });
116 }
117
118 TRY(parse_path_entries([this](PathEntry& entry) {
119 m_source_files.append({ entry.path, entry.directory_index });
120 },
121 PathListType::Filenames));
122
123 return {};
124}
125
126void LineProgram::append_to_line_info()
127{
128 dbgln_if(DWARF_DEBUG, "appending line info: {:p}, {}:{}", m_address, m_source_files[m_file_index].name, m_line);
129 if (!m_is_statement)
130 return;
131
132 if (m_file_index >= m_source_files.size())
133 return;
134
135 auto const& directory = m_source_directories[m_source_files[m_file_index].directory_index];
136
137 StringBuilder full_path(directory.length() + m_source_files[m_file_index].name.length() + 1);
138 full_path.append(directory);
139 full_path.append('/');
140 full_path.append(m_source_files[m_file_index].name);
141
142 m_lines.append({ m_address, DeprecatedFlyString { full_path.string_view() }, m_line });
143}
144
145void LineProgram::reset_registers()
146{
147 m_address = 0;
148 m_line = 1;
149 m_file_index = 1;
150 m_is_statement = m_unit_header.default_is_stmt() == 1;
151}
152
153ErrorOr<void> LineProgram::handle_extended_opcode()
154{
155 size_t length = TRY(m_stream.read_value<LEB128<size_t>>());
156
157 auto sub_opcode = TRY(m_stream.read_value<u8>());
158
159 switch (sub_opcode) {
160 case ExtendedOpcodes::EndSequence: {
161 append_to_line_info();
162 reset_registers();
163 break;
164 }
165 case ExtendedOpcodes::SetAddress: {
166 VERIFY(length == sizeof(size_t) + 1);
167 m_address = TRY(m_stream.read_value<FlatPtr>());
168 dbgln_if(DWARF_DEBUG, "SetAddress: {:p}", m_address);
169 break;
170 }
171 case ExtendedOpcodes::SetDiscriminator: {
172 dbgln_if(DWARF_DEBUG, "SetDiscriminator");
173 [[maybe_unused]] size_t discriminator = TRY(m_stream.read_value<LEB128<size_t>>());
174 break;
175 }
176 default:
177 dbgln("Encountered unknown sub opcode {} at stream offset {:p}", sub_opcode, TRY(m_stream.tell()));
178 VERIFY_NOT_REACHED();
179 }
180
181 return {};
182}
183ErrorOr<void> LineProgram::handle_standard_opcode(u8 opcode)
184{
185 switch (opcode) {
186 case StandardOpcodes::Copy: {
187 append_to_line_info();
188 break;
189 }
190 case StandardOpcodes::AdvancePc: {
191 size_t operand = TRY(m_stream.read_value<LEB128<size_t>>());
192 size_t delta = operand * m_unit_header.min_instruction_length();
193 dbgln_if(DWARF_DEBUG, "AdvancePC by: {} to: {:p}", delta, m_address + delta);
194 m_address += delta;
195 break;
196 }
197 case StandardOpcodes::SetFile: {
198 size_t new_file_index = TRY(m_stream.read_value<LEB128<size_t>>());
199 dbgln_if(DWARF_DEBUG, "SetFile: new file index: {}", new_file_index);
200 m_file_index = new_file_index;
201 break;
202 }
203 case StandardOpcodes::SetColumn: {
204 // not implemented
205 dbgln_if(DWARF_DEBUG, "SetColumn");
206 [[maybe_unused]] size_t new_column = TRY(m_stream.read_value<LEB128<size_t>>());
207
208 break;
209 }
210 case StandardOpcodes::AdvanceLine: {
211 ssize_t line_delta = TRY(m_stream.read_value<LEB128<ssize_t>>());
212 VERIFY(line_delta >= 0 || m_line >= (size_t)(-line_delta));
213 m_line += line_delta;
214 dbgln_if(DWARF_DEBUG, "AdvanceLine: {}", m_line);
215 break;
216 }
217 case StandardOpcodes::NegateStatement: {
218 dbgln_if(DWARF_DEBUG, "NegateStatement");
219 m_is_statement = !m_is_statement;
220 break;
221 }
222 case StandardOpcodes::ConstAddPc: {
223 u8 adjusted_opcode = 255 - m_unit_header.opcode_base();
224 ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range()) * m_unit_header.min_instruction_length();
225 address_increment *= m_unit_header.min_instruction_length();
226 dbgln_if(DWARF_DEBUG, "ConstAddPc: advance pc by: {} to: {}", address_increment, (m_address + address_increment));
227 m_address += address_increment;
228 break;
229 }
230 case StandardOpcodes::SetIsa: {
231 size_t isa = TRY(m_stream.read_value<LEB128<size_t>>());
232 dbgln_if(DWARF_DEBUG, "SetIsa: {}", isa);
233 break;
234 }
235 case StandardOpcodes::FixAdvancePc: {
236 auto delta = TRY(m_stream.read_value<u16>());
237 dbgln_if(DWARF_DEBUG, "FixAdvancePC by: {} to: {:p}", delta, m_address + delta);
238 m_address += delta;
239 break;
240 }
241 case StandardOpcodes::SetBasicBlock: {
242 m_basic_block = true;
243 break;
244 }
245 case StandardOpcodes::SetPrologueEnd: {
246 m_prologue_end = true;
247 break;
248 }
249 default:
250 dbgln("Unhandled LineProgram opcode {}", opcode);
251 VERIFY_NOT_REACHED();
252 }
253
254 return {};
255}
256void LineProgram::handle_special_opcode(u8 opcode)
257{
258 u8 adjusted_opcode = opcode - m_unit_header.opcode_base();
259 ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range()) * m_unit_header.min_instruction_length();
260 ssize_t line_increment = m_unit_header.line_base() + (adjusted_opcode % m_unit_header.line_range());
261
262 m_address += address_increment;
263 m_line += line_increment;
264
265 if constexpr (DWARF_DEBUG) {
266 dbgln("Special adjusted_opcode: {}, address_increment: {}, line_increment: {}", adjusted_opcode, address_increment, line_increment);
267 dbgln("Address is now: {:p}, and line is: {}:{}", m_address, m_source_files[m_file_index].name, m_line);
268 }
269
270 append_to_line_info();
271
272 m_basic_block = false;
273 m_prologue_end = false;
274}
275
276ErrorOr<void> LineProgram::run_program()
277{
278 reset_registers();
279
280 while (TRY(m_stream.tell()) < m_unit_offset + sizeof(u32) + m_unit_header.length()) {
281 auto opcode = TRY(m_stream.read_value<u8>());
282
283 dbgln_if(DWARF_DEBUG, "{:p}: opcode: {}", TRY(m_stream.tell()) - 1, opcode);
284
285 if (opcode == 0) {
286 TRY(handle_extended_opcode());
287 } else if (opcode >= 1 && opcode <= 12) {
288 TRY(handle_standard_opcode(opcode));
289 } else {
290 handle_special_opcode(opcode);
291 }
292 }
293
294 return {};
295}
296
297LineProgram::DirectoryAndFile LineProgram::get_directory_and_file(size_t file_index) const
298{
299 VERIFY(file_index < m_source_files.size());
300 auto file_entry = m_source_files[file_index];
301 VERIFY(file_entry.directory_index < m_source_directories.size());
302 auto directory_entry = m_source_directories[file_entry.directory_index];
303 return { directory_entry, file_entry.name };
304}
305
306bool LineProgram::looks_like_embedded_resource() const
307{
308 if (source_files().size() == 1)
309 return source_files()[0].name.view().contains("serenity_icon_"sv);
310
311 if (source_files().size() == 2 && source_files()[0].name.view() == "."sv)
312 return source_files()[1].name.view().contains("serenity_icon_"sv);
313
314 return false;
315}
316
317}