1 //===-- DWARFFormValue.cpp ------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include <cassert>
10 #include <optional>
11
12 #include "lldb/Core/Module.h"
13 #include "lldb/Core/dwarf.h"
14 #include "lldb/Symbol/ObjectFile.h"
15 #include "lldb/Utility/Stream.h"
16
17 #include "DWARFDebugInfo.h"
18 #include "DWARFFormValue.h"
19 #include "DWARFUnit.h"
20
21 using namespace lldb_private;
22 using namespace lldb_private::dwarf;
23 using namespace lldb_private::plugin::dwarf;
24
Clear()25 void DWARFFormValue::Clear() {
26 m_unit = nullptr;
27 m_form = dw_form_t(0);
28 m_value = ValueTypeTag();
29 }
30
ExtractValue(const DWARFDataExtractor & data,lldb::offset_t * offset_ptr)31 bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data,
32 lldb::offset_t *offset_ptr) {
33 if (m_form == DW_FORM_implicit_const)
34 return true;
35
36 bool indirect = false;
37 bool is_block = false;
38 m_value.data = nullptr;
39 uint8_t ref_addr_size;
40 // Read the value for the form into value and follow and DW_FORM_indirect
41 // instances we run into
42 do {
43 indirect = false;
44 switch (m_form) {
45 case DW_FORM_addr:
46 assert(m_unit);
47 m_value.value.uval =
48 data.GetMaxU64(offset_ptr, DWARFUnit::GetAddressByteSize(m_unit));
49 break;
50 case DW_FORM_block1:
51 m_value.value.uval = data.GetU8(offset_ptr);
52 is_block = true;
53 break;
54 case DW_FORM_block2:
55 m_value.value.uval = data.GetU16(offset_ptr);
56 is_block = true;
57 break;
58 case DW_FORM_block4:
59 m_value.value.uval = data.GetU32(offset_ptr);
60 is_block = true;
61 break;
62 case DW_FORM_data16:
63 m_value.value.uval = 16;
64 is_block = true;
65 break;
66 case DW_FORM_exprloc:
67 case DW_FORM_block:
68 m_value.value.uval = data.GetULEB128(offset_ptr);
69 is_block = true;
70 break;
71 case DW_FORM_string:
72 m_value.value.cstr = data.GetCStr(offset_ptr);
73 break;
74 case DW_FORM_sdata:
75 m_value.value.sval = data.GetSLEB128(offset_ptr);
76 break;
77 case DW_FORM_strp:
78 case DW_FORM_line_strp:
79 case DW_FORM_sec_offset:
80 m_value.value.uval = data.GetMaxU64(offset_ptr, 4);
81 break;
82 case DW_FORM_addrx1:
83 case DW_FORM_strx1:
84 case DW_FORM_ref1:
85 case DW_FORM_data1:
86 case DW_FORM_flag:
87 m_value.value.uval = data.GetU8(offset_ptr);
88 break;
89 case DW_FORM_addrx2:
90 case DW_FORM_strx2:
91 case DW_FORM_ref2:
92 case DW_FORM_data2:
93 m_value.value.uval = data.GetU16(offset_ptr);
94 break;
95 case DW_FORM_addrx3:
96 case DW_FORM_strx3:
97 m_value.value.uval = data.GetMaxU64(offset_ptr, 3);
98 break;
99 case DW_FORM_addrx4:
100 case DW_FORM_strx4:
101 case DW_FORM_ref4:
102 case DW_FORM_data4:
103 m_value.value.uval = data.GetU32(offset_ptr);
104 break;
105 case DW_FORM_data8:
106 case DW_FORM_ref8:
107 case DW_FORM_ref_sig8:
108 m_value.value.uval = data.GetU64(offset_ptr);
109 break;
110 case DW_FORM_addrx:
111 case DW_FORM_loclistx:
112 case DW_FORM_rnglistx:
113 case DW_FORM_strx:
114 case DW_FORM_udata:
115 case DW_FORM_ref_udata:
116 case DW_FORM_GNU_str_index:
117 case DW_FORM_GNU_addr_index:
118 m_value.value.uval = data.GetULEB128(offset_ptr);
119 break;
120 case DW_FORM_ref_addr:
121 assert(m_unit);
122 if (m_unit->GetVersion() <= 2)
123 ref_addr_size = m_unit->GetAddressByteSize();
124 else
125 ref_addr_size = 4;
126 m_value.value.uval = data.GetMaxU64(offset_ptr, ref_addr_size);
127 break;
128 case DW_FORM_indirect:
129 m_form = static_cast<dw_form_t>(data.GetULEB128(offset_ptr));
130 indirect = true;
131 break;
132 case DW_FORM_flag_present:
133 m_value.value.uval = 1;
134 break;
135 default:
136 return false;
137 }
138 } while (indirect);
139
140 if (is_block) {
141 m_value.data = data.PeekData(*offset_ptr, m_value.value.uval);
142 if (m_value.data != nullptr) {
143 *offset_ptr += m_value.value.uval;
144 }
145 }
146
147 return true;
148 }
149
150 struct FormSize {
151 uint8_t valid:1, size:7;
152 };
153 static FormSize g_form_sizes[] = {
154 {0, 0}, // 0x00 unused
155 {0, 0}, // 0x01 DW_FORM_addr
156 {0, 0}, // 0x02 unused
157 {0, 0}, // 0x03 DW_FORM_block2
158 {0, 0}, // 0x04 DW_FORM_block4
159 {1, 2}, // 0x05 DW_FORM_data2
160 {1, 4}, // 0x06 DW_FORM_data4
161 {1, 8}, // 0x07 DW_FORM_data8
162 {0, 0}, // 0x08 DW_FORM_string
163 {0, 0}, // 0x09 DW_FORM_block
164 {0, 0}, // 0x0a DW_FORM_block1
165 {1, 1}, // 0x0b DW_FORM_data1
166 {1, 1}, // 0x0c DW_FORM_flag
167 {0, 0}, // 0x0d DW_FORM_sdata
168 {1, 4}, // 0x0e DW_FORM_strp
169 {0, 0}, // 0x0f DW_FORM_udata
170 {0, 0}, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes
171 // for DWARF32, 8 bytes for DWARF32 in DWARF 3 and later
172 {1, 1}, // 0x11 DW_FORM_ref1
173 {1, 2}, // 0x12 DW_FORM_ref2
174 {1, 4}, // 0x13 DW_FORM_ref4
175 {1, 8}, // 0x14 DW_FORM_ref8
176 {0, 0}, // 0x15 DW_FORM_ref_udata
177 {0, 0}, // 0x16 DW_FORM_indirect
178 {1, 4}, // 0x17 DW_FORM_sec_offset
179 {0, 0}, // 0x18 DW_FORM_exprloc
180 {1, 0}, // 0x19 DW_FORM_flag_present
181 {0, 0}, // 0x1a DW_FORM_strx (ULEB128)
182 {0, 0}, // 0x1b DW_FORM_addrx (ULEB128)
183 {1, 4}, // 0x1c DW_FORM_ref_sup4
184 {0, 0}, // 0x1d DW_FORM_strp_sup (4 bytes for DWARF32, 8 bytes for DWARF64)
185 {1, 16}, // 0x1e DW_FORM_data16
186 {1, 4}, // 0x1f DW_FORM_line_strp
187 {1, 8}, // 0x20 DW_FORM_ref_sig8
188 };
189
GetFixedSize(dw_form_t form,const DWARFUnit * u)190 std::optional<uint8_t> DWARFFormValue::GetFixedSize(dw_form_t form,
191 const DWARFUnit *u) {
192 if (form <= DW_FORM_ref_sig8 && g_form_sizes[form].valid)
193 return static_cast<uint8_t>(g_form_sizes[form].size);
194 if (form == DW_FORM_addr && u)
195 return u->GetAddressByteSize();
196 return std::nullopt;
197 }
198
GetFixedSize() const199 std::optional<uint8_t> DWARFFormValue::GetFixedSize() const {
200 return GetFixedSize(m_form, m_unit);
201 }
202
SkipValue(const DWARFDataExtractor & debug_info_data,lldb::offset_t * offset_ptr) const203 bool DWARFFormValue::SkipValue(const DWARFDataExtractor &debug_info_data,
204 lldb::offset_t *offset_ptr) const {
205 return DWARFFormValue::SkipValue(m_form, debug_info_data, offset_ptr, m_unit);
206 }
207
SkipValue(dw_form_t form,const DWARFDataExtractor & debug_info_data,lldb::offset_t * offset_ptr,const DWARFUnit * unit)208 bool DWARFFormValue::SkipValue(dw_form_t form,
209 const DWARFDataExtractor &debug_info_data,
210 lldb::offset_t *offset_ptr,
211 const DWARFUnit *unit) {
212 uint8_t ref_addr_size;
213 switch (form) {
214 // Blocks if inlined data that have a length field and the data bytes inlined
215 // in the .debug_info
216 case DW_FORM_exprloc:
217 case DW_FORM_block: {
218 uint64_t size = debug_info_data.GetULEB128(offset_ptr);
219 *offset_ptr += size;
220 }
221 return true;
222 case DW_FORM_block1: {
223 uint8_t size = debug_info_data.GetU8(offset_ptr);
224 *offset_ptr += size;
225 }
226 return true;
227 case DW_FORM_block2: {
228 uint16_t size = debug_info_data.GetU16(offset_ptr);
229 *offset_ptr += size;
230 }
231 return true;
232 case DW_FORM_block4: {
233 uint32_t size = debug_info_data.GetU32(offset_ptr);
234 *offset_ptr += size;
235 }
236 return true;
237
238 // Inlined NULL terminated C-strings
239 case DW_FORM_string:
240 debug_info_data.GetCStr(offset_ptr);
241 return true;
242
243 // Compile unit address sized values
244 case DW_FORM_addr:
245 *offset_ptr += DWARFUnit::GetAddressByteSize(unit);
246 return true;
247
248 case DW_FORM_ref_addr:
249 ref_addr_size = 4;
250 assert(unit); // Unit must be valid for DW_FORM_ref_addr objects or we will
251 // get this wrong
252 if (unit->GetVersion() <= 2)
253 ref_addr_size = unit->GetAddressByteSize();
254 else
255 ref_addr_size = 4;
256 *offset_ptr += ref_addr_size;
257 return true;
258
259 // 0 bytes values (implied from DW_FORM)
260 case DW_FORM_flag_present:
261 case DW_FORM_implicit_const:
262 return true;
263
264 // 1 byte values
265 case DW_FORM_addrx1:
266 case DW_FORM_data1:
267 case DW_FORM_flag:
268 case DW_FORM_ref1:
269 case DW_FORM_strx1:
270 *offset_ptr += 1;
271 return true;
272
273 // 2 byte values
274 case DW_FORM_addrx2:
275 case DW_FORM_data2:
276 case DW_FORM_ref2:
277 case DW_FORM_strx2:
278 *offset_ptr += 2;
279 return true;
280
281 // 3 byte values
282 case DW_FORM_addrx3:
283 case DW_FORM_strx3:
284 *offset_ptr += 3;
285 return true;
286
287 // 32 bit for DWARF 32, 64 for DWARF 64
288 case DW_FORM_sec_offset:
289 case DW_FORM_strp:
290 case DW_FORM_line_strp:
291 *offset_ptr += 4;
292 return true;
293
294 // 4 byte values
295 case DW_FORM_addrx4:
296 case DW_FORM_data4:
297 case DW_FORM_ref4:
298 case DW_FORM_strx4:
299 *offset_ptr += 4;
300 return true;
301
302 // 8 byte values
303 case DW_FORM_data8:
304 case DW_FORM_ref8:
305 case DW_FORM_ref_sig8:
306 *offset_ptr += 8;
307 return true;
308
309 // signed or unsigned LEB 128 values
310 case DW_FORM_addrx:
311 case DW_FORM_loclistx:
312 case DW_FORM_rnglistx:
313 case DW_FORM_sdata:
314 case DW_FORM_udata:
315 case DW_FORM_ref_udata:
316 case DW_FORM_GNU_addr_index:
317 case DW_FORM_GNU_str_index:
318 case DW_FORM_strx:
319 debug_info_data.Skip_LEB128(offset_ptr);
320 return true;
321
322 case DW_FORM_indirect: {
323 auto indirect_form =
324 static_cast<dw_form_t>(debug_info_data.GetULEB128(offset_ptr));
325 return DWARFFormValue::SkipValue(indirect_form, debug_info_data,
326 offset_ptr, unit);
327 }
328
329 default:
330 break;
331 }
332 return false;
333 }
334
Dump(Stream & s) const335 void DWARFFormValue::Dump(Stream &s) const {
336 uint64_t uvalue = Unsigned();
337 bool unit_relative_offset = false;
338
339 switch (m_form) {
340 case DW_FORM_addr:
341 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t));
342 break;
343 case DW_FORM_flag:
344 case DW_FORM_data1:
345 s.PutHex8(uvalue);
346 break;
347 case DW_FORM_data2:
348 s.PutHex16(uvalue);
349 break;
350 case DW_FORM_sec_offset:
351 case DW_FORM_data4:
352 s.PutHex32(uvalue);
353 break;
354 case DW_FORM_ref_sig8:
355 case DW_FORM_data8:
356 s.PutHex64(uvalue);
357 break;
358 case DW_FORM_string:
359 s.QuotedCString(AsCString());
360 break;
361 case DW_FORM_exprloc:
362 case DW_FORM_block:
363 case DW_FORM_block1:
364 case DW_FORM_block2:
365 case DW_FORM_block4:
366 if (uvalue > 0) {
367 switch (m_form) {
368 case DW_FORM_exprloc:
369 case DW_FORM_block:
370 s.Printf("<0x%" PRIx64 "> ", uvalue);
371 break;
372 case DW_FORM_block1:
373 s.Printf("<0x%2.2x> ", (uint8_t)uvalue);
374 break;
375 case DW_FORM_block2:
376 s.Printf("<0x%4.4x> ", (uint16_t)uvalue);
377 break;
378 case DW_FORM_block4:
379 s.Printf("<0x%8.8x> ", (uint32_t)uvalue);
380 break;
381 default:
382 break;
383 }
384
385 const uint8_t *data_ptr = m_value.data;
386 if (data_ptr) {
387 const uint8_t *end_data_ptr =
388 data_ptr + uvalue; // uvalue contains size of block
389 while (data_ptr < end_data_ptr) {
390 s.Printf("%2.2x ", *data_ptr);
391 ++data_ptr;
392 }
393 } else
394 s.PutCString("NULL");
395 }
396 break;
397
398 case DW_FORM_sdata:
399 s.PutSLEB128(uvalue);
400 break;
401 case DW_FORM_udata:
402 s.PutULEB128(uvalue);
403 break;
404 case DW_FORM_strp:
405 case DW_FORM_line_strp: {
406 const char *dbg_str = AsCString();
407 if (dbg_str) {
408 s.QuotedCString(dbg_str);
409 } else {
410 s.PutHex32(uvalue);
411 }
412 } break;
413
414 case DW_FORM_ref_addr: {
415 assert(m_unit); // Unit must be valid for DW_FORM_ref_addr objects or we
416 // will get this wrong
417 if (m_unit->GetVersion() <= 2)
418 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t) * 2);
419 else
420 DumpAddress(s.AsRawOstream(), uvalue,
421 4 * 2); // 4 for DWARF32, 8 for DWARF64, but we don't
422 // support DWARF64 yet
423 break;
424 }
425 case DW_FORM_ref1:
426 unit_relative_offset = true;
427 break;
428 case DW_FORM_ref2:
429 unit_relative_offset = true;
430 break;
431 case DW_FORM_ref4:
432 unit_relative_offset = true;
433 break;
434 case DW_FORM_ref8:
435 unit_relative_offset = true;
436 break;
437 case DW_FORM_ref_udata:
438 unit_relative_offset = true;
439 break;
440
441 // All DW_FORM_indirect attributes should be resolved prior to calling this
442 // function
443 case DW_FORM_indirect:
444 s.PutCString("DW_FORM_indirect");
445 break;
446 case DW_FORM_flag_present:
447 break;
448 default:
449 s.Printf("DW_FORM(0x%4.4x)", m_form);
450 break;
451 }
452
453 if (unit_relative_offset) {
454 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile
455 // unit relative or we will get this wrong
456 s.Printf("{0x%8.8" PRIx64 "}", uvalue + m_unit->GetOffset());
457 }
458 }
459
AsCString() const460 const char *DWARFFormValue::AsCString() const {
461 DWARFContext &context = m_unit->GetSymbolFileDWARF().GetDWARFContext();
462
463 if (m_form == DW_FORM_string)
464 return m_value.value.cstr;
465 if (m_form == DW_FORM_strp)
466 return context.getOrLoadStrData().PeekCStr(m_value.value.uval);
467
468 if (m_form == DW_FORM_GNU_str_index || m_form == DW_FORM_strx ||
469 m_form == DW_FORM_strx1 || m_form == DW_FORM_strx2 ||
470 m_form == DW_FORM_strx3 || m_form == DW_FORM_strx4) {
471
472 std::optional<uint64_t> offset =
473 m_unit->GetStringOffsetSectionItem(m_value.value.uval);
474 if (!offset)
475 return nullptr;
476 return context.getOrLoadStrData().PeekCStr(*offset);
477 }
478
479 if (m_form == DW_FORM_line_strp)
480 return context.getOrLoadLineStrData().PeekCStr(m_value.value.uval);
481
482 return nullptr;
483 }
484
Address() const485 dw_addr_t DWARFFormValue::Address() const {
486 SymbolFileDWARF &symbol_file = m_unit->GetSymbolFileDWARF();
487
488 if (m_form == DW_FORM_addr)
489 return Unsigned();
490
491 assert(m_unit);
492 assert(m_form == DW_FORM_GNU_addr_index || m_form == DW_FORM_addrx ||
493 m_form == DW_FORM_addrx1 || m_form == DW_FORM_addrx2 ||
494 m_form == DW_FORM_addrx3 || m_form == DW_FORM_addrx4);
495
496 uint32_t index_size = m_unit->GetAddressByteSize();
497 dw_offset_t addr_base = m_unit->GetAddrBase();
498 lldb::offset_t offset = addr_base + m_value.value.uval * index_size;
499 return symbol_file.GetDWARFContext().getOrLoadAddrData().GetMaxU64(
500 &offset, index_size);
501 }
502
503 std::pair<DWARFUnit *, uint64_t>
ReferencedUnitAndOffset() const504 DWARFFormValue::ReferencedUnitAndOffset() const {
505 uint64_t value = m_value.value.uval;
506 switch (m_form) {
507 case DW_FORM_ref1:
508 case DW_FORM_ref2:
509 case DW_FORM_ref4:
510 case DW_FORM_ref8:
511 case DW_FORM_ref_udata:
512 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile
513 // unit relative or we will get this wrong
514 value += m_unit->GetOffset();
515 if (!m_unit->ContainsDIEOffset(value)) {
516 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
517 "DW_FORM_ref* DIE reference {0:x16} is outside of its CU", value);
518 return {nullptr, 0};
519 }
520 return {const_cast<DWARFUnit *>(m_unit), value};
521
522 case DW_FORM_ref_addr: {
523 DWARFUnit *ref_cu =
524 m_unit->GetSymbolFileDWARF().DebugInfo().GetUnitContainingDIEOffset(
525 DIERef::Section::DebugInfo, value);
526 if (!ref_cu) {
527 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
528 "DW_FORM_ref_addr DIE reference {0:x16} has no matching CU", value);
529 return {nullptr, 0};
530 }
531 return {ref_cu, value};
532 }
533
534 case DW_FORM_ref_sig8: {
535 DWARFTypeUnit *tu =
536 m_unit->GetSymbolFileDWARF().DebugInfo().GetTypeUnitForHash(value);
537 if (!tu)
538 return {nullptr, 0};
539 return {tu, tu->GetTypeOffset()};
540 }
541
542 default:
543 return {nullptr, 0};
544 }
545 }
546
Reference() const547 DWARFDIE DWARFFormValue::Reference() const {
548 auto [unit, offset] = ReferencedUnitAndOffset();
549 return unit ? unit->GetDIE(offset) : DWARFDIE();
550 }
551
Reference(dw_offset_t base_offset) const552 uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const {
553 uint64_t value = m_value.value.uval;
554 switch (m_form) {
555 case DW_FORM_ref1:
556 case DW_FORM_ref2:
557 case DW_FORM_ref4:
558 case DW_FORM_ref8:
559 case DW_FORM_ref_udata:
560 return value + base_offset;
561
562 case DW_FORM_ref_addr:
563 case DW_FORM_ref_sig8:
564 case DW_FORM_GNU_ref_alt:
565 return value;
566
567 default:
568 return DW_INVALID_OFFSET;
569 }
570 }
571
BlockData() const572 const uint8_t *DWARFFormValue::BlockData() const { return m_value.data; }
573
IsBlockForm(const dw_form_t form)574 bool DWARFFormValue::IsBlockForm(const dw_form_t form) {
575 switch (form) {
576 case DW_FORM_exprloc:
577 case DW_FORM_block:
578 case DW_FORM_block1:
579 case DW_FORM_block2:
580 case DW_FORM_block4:
581 return true;
582 default:
583 return false;
584 }
585 llvm_unreachable("All cases handled above!");
586 }
587
IsDataForm(const dw_form_t form)588 bool DWARFFormValue::IsDataForm(const dw_form_t form) {
589 switch (form) {
590 case DW_FORM_sdata:
591 case DW_FORM_udata:
592 case DW_FORM_data1:
593 case DW_FORM_data2:
594 case DW_FORM_data4:
595 case DW_FORM_data8:
596 return true;
597 default:
598 return false;
599 }
600 llvm_unreachable("All cases handled above!");
601 }
602
FormIsSupported(dw_form_t form)603 bool DWARFFormValue::FormIsSupported(dw_form_t form) {
604 switch (form) {
605 case DW_FORM_addr:
606 case DW_FORM_addrx:
607 case DW_FORM_loclistx:
608 case DW_FORM_rnglistx:
609 case DW_FORM_block2:
610 case DW_FORM_block4:
611 case DW_FORM_data2:
612 case DW_FORM_data4:
613 case DW_FORM_data8:
614 case DW_FORM_string:
615 case DW_FORM_block:
616 case DW_FORM_block1:
617 case DW_FORM_data1:
618 case DW_FORM_flag:
619 case DW_FORM_sdata:
620 case DW_FORM_strp:
621 case DW_FORM_line_strp:
622 case DW_FORM_strx:
623 case DW_FORM_strx1:
624 case DW_FORM_strx2:
625 case DW_FORM_strx3:
626 case DW_FORM_strx4:
627 case DW_FORM_udata:
628 case DW_FORM_ref_addr:
629 case DW_FORM_ref1:
630 case DW_FORM_ref2:
631 case DW_FORM_ref4:
632 case DW_FORM_ref8:
633 case DW_FORM_ref_udata:
634 case DW_FORM_indirect:
635 case DW_FORM_sec_offset:
636 case DW_FORM_exprloc:
637 case DW_FORM_flag_present:
638 case DW_FORM_ref_sig8:
639 case DW_FORM_GNU_str_index:
640 case DW_FORM_GNU_addr_index:
641 case DW_FORM_implicit_const:
642 return true;
643 default:
644 break;
645 }
646 return false;
647 }
648