1//===-- DWARFCallFrameInfo.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 "lldb/Symbol/DWARFCallFrameInfo.h"
10#include "lldb/Core/Debugger.h"
11#include "lldb/Core/Module.h"
12#include "lldb/Core/Section.h"
13#include "lldb/Core/dwarf.h"
14#include "lldb/Host/Host.h"
15#include "lldb/Symbol/ObjectFile.h"
16#include "lldb/Symbol/UnwindPlan.h"
17#include "lldb/Target/RegisterContext.h"
18#include "lldb/Target/Thread.h"
19#include "lldb/Utility/ArchSpec.h"
20#include "lldb/Utility/LLDBLog.h"
21#include "lldb/Utility/Log.h"
22#include "lldb/Utility/Timer.h"
23#include <cstring>
24#include <list>
25#include <optional>
26
27using namespace lldb;
28using namespace lldb_private;
29using namespace lldb_private::dwarf;
30
31// GetDwarfEHPtr
32//
33// Used for calls when the value type is specified by a DWARF EH Frame pointer
34// encoding.
35static uint64_t
36GetGNUEHPointer(const DataExtractor &DE, offset_t *offset_ptr,
37 uint32_t eh_ptr_enc, addr_t pc_rel_addr, addr_t text_addr,
38 addr_t data_addr) //, BSDRelocs *data_relocs) const
39{
40 if (eh_ptr_enc == DW_EH_PE_omit)
41 return ULLONG_MAX; // Value isn't in the buffer...
42
43 uint64_t baseAddress = 0;
44 uint64_t addressValue = 0;
45 const uint32_t addr_size = DE.GetAddressByteSize();
46 assert(addr_size == 4 || addr_size == 8);
47
48 bool signExtendValue = false;
49 // Decode the base part or adjust our offset
50 switch (eh_ptr_enc & 0x70) {
51 case DW_EH_PE_pcrel:
52 signExtendValue = true;
53 baseAddress = *offset_ptr;
54 if (pc_rel_addr != LLDB_INVALID_ADDRESS)
55 baseAddress += pc_rel_addr;
56 // else
57 // Log::GlobalWarning ("PC relative pointer encoding found with
58 // invalid pc relative address.");
59 break;
60
61 case DW_EH_PE_textrel:
62 signExtendValue = true;
63 if (text_addr != LLDB_INVALID_ADDRESS)
64 baseAddress = text_addr;
65 // else
66 // Log::GlobalWarning ("text relative pointer encoding being
67 // decoded with invalid text section address, setting base address
68 // to zero.");
69 break;
70
71 case DW_EH_PE_datarel:
72 signExtendValue = true;
73 if (data_addr != LLDB_INVALID_ADDRESS)
74 baseAddress = data_addr;
75 // else
76 // Log::GlobalWarning ("data relative pointer encoding being
77 // decoded with invalid data section address, setting base address
78 // to zero.");
79 break;
80
81 case DW_EH_PE_funcrel:
82 signExtendValue = true;
83 break;
84
85 case DW_EH_PE_aligned: {
86 // SetPointerSize should be called prior to extracting these so the pointer
87 // size is cached
88 assert(addr_size != 0);
89 if (addr_size) {
90 // Align to a address size boundary first
91 uint32_t alignOffset = *offset_ptr % addr_size;
92 if (alignOffset)
93 offset_ptr += addr_size - alignOffset;
94 }
95 } break;
96
97 default:
98 break;
99 }
100
101 // Decode the value part
102 switch (eh_ptr_enc & DW_EH_PE_MASK_ENCODING) {
103 case DW_EH_PE_absptr: {
104 addressValue = DE.GetAddress(offset_ptr);
105 // if (data_relocs)
106 // addressValue = data_relocs->Relocate(*offset_ptr -
107 // addr_size, *this, addressValue);
108 } break;
109 case DW_EH_PE_uleb128:
110 addressValue = DE.GetULEB128(offset_ptr);
111 break;
112 case DW_EH_PE_udata2:
113 addressValue = DE.GetU16(offset_ptr);
114 break;
115 case DW_EH_PE_udata4:
116 addressValue = DE.GetU32(offset_ptr);
117 break;
118 case DW_EH_PE_udata8:
119 addressValue = DE.GetU64(offset_ptr);
120 break;
121 case DW_EH_PE_sleb128:
122 addressValue = DE.GetSLEB128(offset_ptr);
123 break;
124 case DW_EH_PE_sdata2:
125 addressValue = (int16_t)DE.GetU16(offset_ptr);
126 break;
127 case DW_EH_PE_sdata4:
128 addressValue = (int32_t)DE.GetU32(offset_ptr);
129 break;
130 case DW_EH_PE_sdata8:
131 addressValue = (int64_t)DE.GetU64(offset_ptr);
132 break;
133 default:
134 // Unhandled encoding type
135 assert(eh_ptr_enc);
136 break;
137 }
138
139 // Since we promote everything to 64 bit, we may need to sign extend
140 if (signExtendValue && addr_size < sizeof(baseAddress)) {
141 uint64_t sign_bit = 1ull << ((addr_size * 8ull) - 1ull);
142 if (sign_bit & addressValue) {
143 uint64_t mask = ~sign_bit + 1;
144 addressValue |= mask;
145 }
146 }
147 return baseAddress + addressValue;
148}
149
150DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile &objfile,
151 SectionSP &section_sp, Type type)
152 : m_objfile(objfile), m_section_sp(section_sp), m_type(type) {}
153
154bool DWARFCallFrameInfo::GetUnwindPlan(const Address &addr,
155 UnwindPlan &unwind_plan) {
156 return GetUnwindPlan(range: AddressRange(addr, 1), unwind_plan);
157}
158
159bool DWARFCallFrameInfo::GetUnwindPlan(const AddressRange &range,
160 UnwindPlan &unwind_plan) {
161 FDEEntryMap::Entry fde_entry;
162 Address addr = range.GetBaseAddress();
163
164 // Make sure that the Address we're searching for is the same object file as
165 // this DWARFCallFrameInfo, we only store File offsets in m_fde_index.
166 ModuleSP module_sp = addr.GetModule();
167 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr ||
168 module_sp->GetObjectFile() != &m_objfile)
169 return false;
170
171 if (std::optional<FDEEntryMap::Entry> entry = GetFirstFDEEntryInRange(range))
172 return FDEToUnwindPlan(offset: entry->data, startaddr: addr, unwind_plan);
173 return false;
174}
175
176bool DWARFCallFrameInfo::GetAddressRange(Address addr, AddressRange &range) {
177
178 // Make sure that the Address we're searching for is the same object file as
179 // this DWARFCallFrameInfo, we only store File offsets in m_fde_index.
180 ModuleSP module_sp = addr.GetModule();
181 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr ||
182 module_sp->GetObjectFile() != &m_objfile)
183 return false;
184
185 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted())
186 return false;
187 GetFDEIndex();
188 FDEEntryMap::Entry *fde_entry =
189 m_fde_index.FindEntryThatContains(addr: addr.GetFileAddress());
190 if (!fde_entry)
191 return false;
192
193 range = AddressRange(fde_entry->base, fde_entry->size,
194 m_objfile.GetSectionList());
195 return true;
196}
197
198std::optional<DWARFCallFrameInfo::FDEEntryMap::Entry>
199DWARFCallFrameInfo::GetFirstFDEEntryInRange(const AddressRange &range) {
200 if (!m_section_sp || m_section_sp->IsEncrypted())
201 return std::nullopt;
202
203 GetFDEIndex();
204
205 addr_t start_file_addr = range.GetBaseAddress().GetFileAddress();
206 const FDEEntryMap::Entry *fde =
207 m_fde_index.FindEntryThatContainsOrFollows(addr: start_file_addr);
208 if (fde && fde->DoesIntersect(
209 rhs: FDEEntryMap::Range(start_file_addr, range.GetByteSize())))
210 return *fde;
211
212 return std::nullopt;
213}
214
215void DWARFCallFrameInfo::GetFunctionAddressAndSizeVector(
216 FunctionAddressAndSizeVector &function_info) {
217 GetFDEIndex();
218 const size_t count = m_fde_index.GetSize();
219 function_info.Clear();
220 if (count > 0)
221 function_info.Reserve(size: count);
222 for (size_t i = 0; i < count; ++i) {
223 const FDEEntryMap::Entry *func_offset_data_entry =
224 m_fde_index.GetEntryAtIndex(i);
225 if (func_offset_data_entry) {
226 FunctionAddressAndSizeVector::Entry function_offset_entry(
227 func_offset_data_entry->base, func_offset_data_entry->size);
228 function_info.Append(entry: function_offset_entry);
229 }
230 }
231}
232
233const DWARFCallFrameInfo::CIE *
234DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) {
235 cie_map_t::iterator pos = m_cie_map.find(x: cie_offset);
236
237 if (pos != m_cie_map.end()) {
238 // Parse and cache the CIE
239 if (pos->second == nullptr)
240 pos->second = ParseCIE(cie_offset);
241
242 return pos->second.get();
243 }
244 return nullptr;
245}
246
247DWARFCallFrameInfo::CIESP
248DWARFCallFrameInfo::ParseCIE(const dw_offset_t cie_offset) {
249 CIESP cie_sp(new CIE(cie_offset));
250 lldb::offset_t offset = cie_offset;
251 if (!m_cfi_data_initialized)
252 GetCFIData();
253 uint32_t length = m_cfi_data.GetU32(offset_ptr: &offset);
254 dw_offset_t cie_id, end_offset;
255 bool is_64bit = (length == UINT32_MAX);
256 if (is_64bit) {
257 length = m_cfi_data.GetU64(offset_ptr: &offset);
258 cie_id = m_cfi_data.GetU64(offset_ptr: &offset);
259 end_offset = cie_offset + length + 12;
260 } else {
261 cie_id = m_cfi_data.GetU32(offset_ptr: &offset);
262 end_offset = cie_offset + length + 4;
263 }
264 if (length > 0 && ((m_type == DWARF && cie_id == UINT32_MAX) ||
265 (m_type == EH && cie_id == 0ul))) {
266 size_t i;
267 // cie.offset = cie_offset;
268 // cie.length = length;
269 // cie.cieID = cieID;
270 cie_sp->ptr_encoding = DW_EH_PE_absptr; // default
271 cie_sp->version = m_cfi_data.GetU8(offset_ptr: &offset);
272 if (cie_sp->version > CFI_VERSION4) {
273 Debugger::ReportError(
274 message: llvm::formatv(Fmt: "CIE parse error: CFI version {0} is not supported",
275 Vals&: cie_sp->version));
276 return nullptr;
277 }
278
279 for (i = 0; i < CFI_AUG_MAX_SIZE; ++i) {
280 cie_sp->augmentation[i] = m_cfi_data.GetU8(offset_ptr: &offset);
281 if (cie_sp->augmentation[i] == '\0') {
282 // Zero out remaining bytes in augmentation string
283 for (size_t j = i + 1; j < CFI_AUG_MAX_SIZE; ++j)
284 cie_sp->augmentation[j] = '\0';
285
286 break;
287 }
288 }
289
290 if (i == CFI_AUG_MAX_SIZE &&
291 cie_sp->augmentation[CFI_AUG_MAX_SIZE - 1] != '\0') {
292 Debugger::ReportError(message: llvm::formatv(
293 Fmt: "CIE parse error: CIE augmentation string was too large "
294 "for the fixed sized buffer of {0} bytes.",
295 Vals: CFI_AUG_MAX_SIZE));
296 return nullptr;
297 }
298
299 // m_cfi_data uses address size from target architecture of the process may
300 // ignore these fields?
301 if (m_type == DWARF && cie_sp->version >= CFI_VERSION4) {
302 cie_sp->address_size = m_cfi_data.GetU8(offset_ptr: &offset);
303 cie_sp->segment_size = m_cfi_data.GetU8(offset_ptr: &offset);
304 }
305
306 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
307 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(offset_ptr: &offset);
308
309 cie_sp->return_addr_reg_num =
310 m_type == DWARF && cie_sp->version >= CFI_VERSION3
311 ? static_cast<uint32_t>(m_cfi_data.GetULEB128(offset_ptr: &offset))
312 : m_cfi_data.GetU8(offset_ptr: &offset);
313
314 if (cie_sp->augmentation[0]) {
315 // Get the length of the eh_frame augmentation data which starts with a
316 // ULEB128 length in bytes
317 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
318 const size_t aug_data_end = offset + aug_data_len;
319 const size_t aug_str_len = strlen(s: cie_sp->augmentation);
320 // A 'z' may be present as the first character of the string.
321 // If present, the Augmentation Data field shall be present. The contents
322 // of the Augmentation Data shall be interpreted according to other
323 // characters in the Augmentation String.
324 if (cie_sp->augmentation[0] == 'z') {
325 // Extract the Augmentation Data
326 size_t aug_str_idx = 0;
327 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) {
328 char aug = cie_sp->augmentation[aug_str_idx];
329 switch (aug) {
330 case 'L':
331 // Indicates the presence of one argument in the Augmentation Data
332 // of the CIE, and a corresponding argument in the Augmentation
333 // Data of the FDE. The argument in the Augmentation Data of the
334 // CIE is 1-byte and represents the pointer encoding used for the
335 // argument in the Augmentation Data of the FDE, which is the
336 // address of a language-specific data area (LSDA). The size of the
337 // LSDA pointer is specified by the pointer encoding used.
338 cie_sp->lsda_addr_encoding = m_cfi_data.GetU8(offset_ptr: &offset);
339 break;
340
341 case 'P':
342 // Indicates the presence of two arguments in the Augmentation Data
343 // of the CIE. The first argument is 1-byte and represents the
344 // pointer encoding used for the second argument, which is the
345 // address of a personality routine handler. The size of the
346 // personality routine pointer is specified by the pointer encoding
347 // used.
348 //
349 // The address of the personality function will be stored at this
350 // location. Pre-execution, it will be all zero's so don't read it
351 // until we're trying to do an unwind & the reloc has been
352 // resolved.
353 {
354 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(offset_ptr: &offset);
355 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
356 cie_sp->personality_loc = GetGNUEHPointer(
357 DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: arg_ptr_encoding, pc_rel_addr,
358 LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS);
359 }
360 break;
361
362 case 'R':
363 // A 'R' may be present at any position after the
364 // first character of the string. The Augmentation Data shall
365 // include a 1 byte argument that represents the pointer encoding
366 // for the address pointers used in the FDE. Example: 0x1B ==
367 // DW_EH_PE_pcrel | DW_EH_PE_sdata4
368 cie_sp->ptr_encoding = m_cfi_data.GetU8(offset_ptr: &offset);
369 break;
370 }
371 }
372 } else if (strcmp(s1: cie_sp->augmentation, s2: "eh") == 0) {
373 // If the Augmentation string has the value "eh", then the EH Data
374 // field shall be present
375 }
376
377 // Set the offset to be the end of the augmentation data just in case we
378 // didn't understand any of the data.
379 offset = (uint32_t)aug_data_end;
380 }
381
382 if (end_offset > offset) {
383 cie_sp->inst_offset = offset;
384 cie_sp->inst_length = end_offset - offset;
385 }
386 while (offset < end_offset) {
387 uint8_t inst = m_cfi_data.GetU8(offset_ptr: &offset);
388 uint8_t primary_opcode = inst & 0xC0;
389 uint8_t extended_opcode = inst & 0x3F;
390
391 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode,
392 data_align: cie_sp->data_align, offset,
393 row&: cie_sp->initial_row))
394 break; // Stop if we hit an unrecognized opcode
395 }
396 }
397
398 return cie_sp;
399}
400
401void DWARFCallFrameInfo::GetCFIData() {
402 if (!m_cfi_data_initialized) {
403 Log *log = GetLog(mask: LLDBLog::Unwind);
404 if (log)
405 m_objfile.GetModule()->LogMessage(log, format: "Reading EH frame info");
406 m_objfile.ReadSectionData(section: m_section_sp.get(), section_data&: m_cfi_data);
407 m_cfi_data_initialized = true;
408 }
409}
410// Scan through the eh_frame or debug_frame section looking for FDEs and noting
411// the start/end addresses of the functions and a pointer back to the
412// function's FDE for later expansion. Internalize CIEs as we come across them.
413
414void DWARFCallFrameInfo::GetFDEIndex() {
415 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted())
416 return;
417
418 if (m_fde_index_initialized)
419 return;
420
421 std::lock_guard<std::mutex> guard(m_fde_index_mutex);
422
423 if (m_fde_index_initialized) // if two threads hit the locker
424 return;
425
426 LLDB_SCOPED_TIMERF("%s - %s", LLVM_PRETTY_FUNCTION,
427 m_objfile.GetFileSpec().GetFilename().AsCString(""));
428
429 bool clear_address_zeroth_bit = false;
430 if (ArchSpec arch = m_objfile.GetArchitecture()) {
431 if (arch.GetTriple().getArch() == llvm::Triple::arm ||
432 arch.GetTriple().getArch() == llvm::Triple::thumb)
433 clear_address_zeroth_bit = true;
434 }
435
436 lldb::offset_t offset = 0;
437 if (!m_cfi_data_initialized)
438 GetCFIData();
439 while (m_cfi_data.ValidOffsetForDataOfSize(offset, length: 8)) {
440 const dw_offset_t current_entry = offset;
441 dw_offset_t cie_id, next_entry, cie_offset;
442 uint32_t len = m_cfi_data.GetU32(offset_ptr: &offset);
443 bool is_64bit = (len == UINT32_MAX);
444 if (is_64bit) {
445 len = m_cfi_data.GetU64(offset_ptr: &offset);
446 cie_id = m_cfi_data.GetU64(offset_ptr: &offset);
447 next_entry = current_entry + len + 12;
448 cie_offset = current_entry + 12 - cie_id;
449 } else {
450 cie_id = m_cfi_data.GetU32(offset_ptr: &offset);
451 next_entry = current_entry + len + 4;
452 cie_offset = current_entry + 4 - cie_id;
453 }
454
455 if (next_entry > m_cfi_data.GetByteSize() + 1) {
456 Debugger::ReportError(message: llvm::formatv(Fmt: "Invalid fde/cie next entry offset "
457 "of {0:x} found in cie/fde at {1:x}",
458 Vals&: next_entry, Vals: current_entry));
459 // Don't trust anything in this eh_frame section if we find blatantly
460 // invalid data.
461 m_fde_index.Clear();
462 m_fde_index_initialized = true;
463 return;
464 }
465
466 // An FDE entry contains CIE_pointer in debug_frame in same place as cie_id
467 // in eh_frame. CIE_pointer is an offset into the .debug_frame section. So,
468 // variable cie_offset should be equal to cie_id for debug_frame.
469 // FDE entries with cie_id == 0 shouldn't be ignored for it.
470 if ((cie_id == 0 && m_type == EH) || cie_id == UINT32_MAX || len == 0) {
471 auto cie_sp = ParseCIE(cie_offset: current_entry);
472 if (!cie_sp) {
473 // Cannot parse, the reason is already logged
474 m_fde_index.Clear();
475 m_fde_index_initialized = true;
476 return;
477 }
478
479 m_cie_map[current_entry] = std::move(cie_sp);
480 offset = next_entry;
481 continue;
482 }
483
484 if (m_type == DWARF)
485 cie_offset = cie_id;
486
487 if (cie_offset > m_cfi_data.GetByteSize()) {
488 Debugger::ReportError(message: llvm::formatv(Fmt: "Invalid cie offset of {0:x} "
489 "found in cie/fde at {1:x}",
490 Vals&: cie_offset, Vals: current_entry));
491 // Don't trust anything in this eh_frame section if we find blatantly
492 // invalid data.
493 m_fde_index.Clear();
494 m_fde_index_initialized = true;
495 return;
496 }
497
498 const CIE *cie = GetCIE(cie_offset);
499 if (cie) {
500 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
501 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
502 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
503
504 lldb::addr_t addr =
505 GetGNUEHPointer(DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: cie->ptr_encoding, pc_rel_addr,
506 text_addr, data_addr);
507 if (clear_address_zeroth_bit)
508 addr &= ~1ull;
509
510 lldb::addr_t length = GetGNUEHPointer(
511 DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: cie->ptr_encoding & DW_EH_PE_MASK_ENCODING,
512 pc_rel_addr, text_addr, data_addr);
513 FDEEntryMap::Entry fde(addr, length, current_entry);
514 m_fde_index.Append(entry: fde);
515 } else {
516 Debugger::ReportError(message: llvm::formatv(
517 Fmt: "unable to find CIE at {0:x} for cie_id = {1:x} for entry at {2:x}.",
518 Vals&: cie_offset, Vals&: cie_id, Vals: current_entry));
519 }
520 offset = next_entry;
521 }
522 m_fde_index.Sort();
523 m_fde_index_initialized = true;
524}
525
526bool DWARFCallFrameInfo::FDEToUnwindPlan(dw_offset_t dwarf_offset,
527 Address startaddr,
528 UnwindPlan &unwind_plan) {
529 Log *log = GetLog(mask: LLDBLog::Unwind);
530 lldb::offset_t offset = dwarf_offset;
531 lldb::offset_t current_entry = offset;
532
533 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted())
534 return false;
535
536 if (!m_cfi_data_initialized)
537 GetCFIData();
538
539 uint32_t length = m_cfi_data.GetU32(offset_ptr: &offset);
540 dw_offset_t cie_offset;
541 bool is_64bit = (length == UINT32_MAX);
542 if (is_64bit) {
543 length = m_cfi_data.GetU64(offset_ptr: &offset);
544 cie_offset = m_cfi_data.GetU64(offset_ptr: &offset);
545 } else {
546 cie_offset = m_cfi_data.GetU32(offset_ptr: &offset);
547 }
548
549 // FDE entries with zeroth cie_offset may occur for debug_frame.
550 assert(!(m_type == EH && 0 == cie_offset) && cie_offset != UINT32_MAX);
551
552 // Translate the CIE_id from the eh_frame format, which is relative to the
553 // FDE offset, into a __eh_frame section offset
554 if (m_type == EH) {
555 unwind_plan.SetSourceName("eh_frame CFI");
556 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset;
557 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
558 } else {
559 unwind_plan.SetSourceName("DWARF CFI");
560 // In theory the debug_frame info should be valid at all call sites
561 // ("asynchronous unwind info" as it is sometimes called) but in practice
562 // gcc et al all emit call frame info for the prologue and call sites, but
563 // not for the epilogue or all the other locations during the function
564 // reliably.
565 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
566 }
567 unwind_plan.SetSourcedFromCompiler(eLazyBoolYes);
568
569 const CIE *cie = GetCIE(cie_offset);
570 assert(cie != nullptr);
571
572 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4);
573
574 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
575 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
576 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
577 lldb::addr_t range_base =
578 GetGNUEHPointer(DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: cie->ptr_encoding, pc_rel_addr,
579 text_addr, data_addr);
580 lldb::addr_t range_len = GetGNUEHPointer(
581 DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: cie->ptr_encoding & DW_EH_PE_MASK_ENCODING,
582 pc_rel_addr, text_addr, data_addr);
583 AddressRange range(range_base, m_objfile.GetAddressByteSize(),
584 m_objfile.GetSectionList());
585 range.SetByteSize(range_len);
586
587 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS;
588
589 if (cie->augmentation[0] == 'z') {
590 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
591 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) {
592 offset_t saved_offset = offset;
593 lsda_data_file_address =
594 GetGNUEHPointer(DE: m_cfi_data, offset_ptr: &offset, eh_ptr_enc: cie->lsda_addr_encoding,
595 pc_rel_addr, text_addr, data_addr);
596 if (offset - saved_offset != aug_data_len) {
597 // There is more in the augmentation region than we know how to process;
598 // don't read anything.
599 lsda_data_file_address = LLDB_INVALID_ADDRESS;
600 }
601 offset = saved_offset;
602 }
603 offset += aug_data_len;
604 }
605 unwind_plan.SetUnwindPlanForSignalTrap(
606 strchr(s: cie->augmentation, c: 'S') ? eLazyBoolYes : eLazyBoolNo);
607
608 Address lsda_data;
609 Address personality_function_ptr;
610
611 if (lsda_data_file_address != LLDB_INVALID_ADDRESS &&
612 cie->personality_loc != LLDB_INVALID_ADDRESS) {
613 m_objfile.GetModule()->ResolveFileAddress(vm_addr: lsda_data_file_address,
614 so_addr&: lsda_data);
615 m_objfile.GetModule()->ResolveFileAddress(vm_addr: cie->personality_loc,
616 so_addr&: personality_function_ptr);
617 }
618
619 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) {
620 unwind_plan.SetLSDAAddress(lsda_data);
621 unwind_plan.SetPersonalityFunctionPtr(personality_function_ptr);
622 }
623
624 uint32_t code_align = cie->code_align;
625 int32_t data_align = cie->data_align;
626
627 unwind_plan.SetPlanValidAddressRange(range);
628 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row;
629 *cie_initial_row = cie->initial_row;
630 UnwindPlan::RowSP row(cie_initial_row);
631
632 unwind_plan.SetRegisterKind(GetRegisterKind());
633 unwind_plan.SetReturnAddressRegister(cie->return_addr_reg_num);
634
635 std::vector<UnwindPlan::RowSP> stack;
636
637 UnwindPlan::Row::RegisterLocation reg_location;
638 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) {
639 uint8_t inst = m_cfi_data.GetU8(offset_ptr: &offset);
640 uint8_t primary_opcode = inst & 0xC0;
641 uint8_t extended_opcode = inst & 0x3F;
642
643 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align,
644 offset, row&: *row)) {
645 if (primary_opcode) {
646 switch (primary_opcode) {
647 case DW_CFA_advance_loc: // (Row Creation Instruction)
648 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta
649 // takes a single argument that represents a constant delta. The
650 // required action is to create a new table row with a location value
651 // that is computed by taking the current entry's location value and
652 // adding (delta * code_align). All other values in the new row are
653 // initially identical to the current row.
654 unwind_plan.AppendRow(row_sp: row);
655 UnwindPlan::Row *newrow = new UnwindPlan::Row;
656 *newrow = *row.get();
657 row.reset(p: newrow);
658 row->SlideOffset(offset: extended_opcode * code_align);
659 break;
660 }
661
662 case DW_CFA_restore: { // 0xC0 - high 2 bits are 0x3, lower 6 bits are
663 // register
664 // takes a single argument that represents a register number. The
665 // required action is to change the rule for the indicated register
666 // to the rule assigned it by the initial_instructions in the CIE.
667 uint32_t reg_num = extended_opcode;
668 // We only keep enough register locations around to unwind what is in
669 // our thread, and these are organized by the register index in that
670 // state, so we need to convert our eh_frame register number from the
671 // EH frame info, to a register index
672
673 if (unwind_plan.IsValidRowIndex(idx: 0) &&
674 unwind_plan.GetRowAtIndex(idx: 0)->GetRegisterInfo(reg_num,
675 register_location&: reg_location))
676 row->SetRegisterInfo(reg_num, register_location: reg_location);
677 else {
678 // If the register was not set in the first row, remove the
679 // register info to keep the unmodified value from the caller.
680 row->RemoveRegisterInfo(reg_num);
681 }
682 break;
683 }
684 }
685 } else {
686 switch (extended_opcode) {
687 case DW_CFA_set_loc: // 0x1 (Row Creation Instruction)
688 {
689 // DW_CFA_set_loc takes a single argument that represents an address.
690 // The required action is to create a new table row using the
691 // specified address as the location. All other values in the new row
692 // are initially identical to the current row. The new location value
693 // should always be greater than the current one.
694 unwind_plan.AppendRow(row_sp: row);
695 UnwindPlan::Row *newrow = new UnwindPlan::Row;
696 *newrow = *row.get();
697 row.reset(p: newrow);
698 row->SetOffset(m_cfi_data.GetAddress(offset_ptr: &offset) -
699 startaddr.GetFileAddress());
700 break;
701 }
702
703 case DW_CFA_advance_loc1: // 0x2 (Row Creation Instruction)
704 {
705 // takes a single uword argument that represents a constant delta.
706 // This instruction is identical to DW_CFA_advance_loc except for the
707 // encoding and size of the delta argument.
708 unwind_plan.AppendRow(row_sp: row);
709 UnwindPlan::Row *newrow = new UnwindPlan::Row;
710 *newrow = *row.get();
711 row.reset(p: newrow);
712 row->SlideOffset(offset: m_cfi_data.GetU8(offset_ptr: &offset) * code_align);
713 break;
714 }
715
716 case DW_CFA_advance_loc2: // 0x3 (Row Creation Instruction)
717 {
718 // takes a single uword argument that represents a constant delta.
719 // This instruction is identical to DW_CFA_advance_loc except for the
720 // encoding and size of the delta argument.
721 unwind_plan.AppendRow(row_sp: row);
722 UnwindPlan::Row *newrow = new UnwindPlan::Row;
723 *newrow = *row.get();
724 row.reset(p: newrow);
725 row->SlideOffset(offset: m_cfi_data.GetU16(offset_ptr: &offset) * code_align);
726 break;
727 }
728
729 case DW_CFA_advance_loc4: // 0x4 (Row Creation Instruction)
730 {
731 // takes a single uword argument that represents a constant delta.
732 // This instruction is identical to DW_CFA_advance_loc except for the
733 // encoding and size of the delta argument.
734 unwind_plan.AppendRow(row_sp: row);
735 UnwindPlan::Row *newrow = new UnwindPlan::Row;
736 *newrow = *row.get();
737 row.reset(p: newrow);
738 row->SlideOffset(offset: m_cfi_data.GetU32(offset_ptr: &offset) * code_align);
739 break;
740 }
741
742 case DW_CFA_restore_extended: // 0x6
743 {
744 // takes a single unsigned LEB128 argument that represents a register
745 // number. This instruction is identical to DW_CFA_restore except for
746 // the encoding and size of the register argument.
747 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
748 if (unwind_plan.IsValidRowIndex(idx: 0) &&
749 unwind_plan.GetRowAtIndex(idx: 0)->GetRegisterInfo(reg_num,
750 register_location&: reg_location))
751 row->SetRegisterInfo(reg_num, register_location: reg_location);
752 break;
753 }
754
755 case DW_CFA_remember_state: // 0xA
756 {
757 // These instructions define a stack of information. Encountering the
758 // DW_CFA_remember_state instruction means to save the rules for
759 // every register on the current row on the stack. Encountering the
760 // DW_CFA_restore_state instruction means to pop the set of rules off
761 // the stack and place them in the current row. (This operation is
762 // useful for compilers that move epilogue code into the body of a
763 // function.)
764 stack.push_back(x: row);
765 UnwindPlan::Row *newrow = new UnwindPlan::Row;
766 *newrow = *row.get();
767 row.reset(p: newrow);
768 break;
769 }
770
771 case DW_CFA_restore_state: // 0xB
772 {
773 // These instructions define a stack of information. Encountering the
774 // DW_CFA_remember_state instruction means to save the rules for
775 // every register on the current row on the stack. Encountering the
776 // DW_CFA_restore_state instruction means to pop the set of rules off
777 // the stack and place them in the current row. (This operation is
778 // useful for compilers that move epilogue code into the body of a
779 // function.)
780 if (stack.empty()) {
781 LLDB_LOG(log,
782 "DWARFCallFrameInfo::{0}(dwarf_offset: "
783 "{1:x16}, startaddr: [{2:x16}] encountered "
784 "DW_CFA_restore_state but state stack "
785 "is empty. Corrupt unwind info?",
786 __FUNCTION__, dwarf_offset, startaddr.GetFileAddress());
787 break;
788 }
789 lldb::addr_t offset = row->GetOffset();
790 row = stack.back();
791 stack.pop_back();
792 row->SetOffset(offset);
793 break;
794 }
795
796 case DW_CFA_GNU_args_size: // 0x2e
797 {
798 // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128
799 // operand representing an argument size. This instruction specifies
800 // the total of the size of the arguments which have been pushed onto
801 // the stack.
802
803 // TODO: Figure out how we should handle this.
804 m_cfi_data.GetULEB128(offset_ptr: &offset);
805 break;
806 }
807
808 case DW_CFA_val_offset: // 0x14
809 case DW_CFA_val_offset_sf: // 0x15
810 default:
811 break;
812 }
813 }
814 }
815 }
816 unwind_plan.AppendRow(row_sp: row);
817
818 return true;
819}
820
821bool DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode,
822 uint8_t extended_opcode,
823 int32_t data_align,
824 lldb::offset_t &offset,
825 UnwindPlan::Row &row) {
826 UnwindPlan::Row::RegisterLocation reg_location;
827
828 if (primary_opcode) {
829 switch (primary_opcode) {
830 case DW_CFA_offset: { // 0x80 - high 2 bits are 0x2, lower 6 bits are
831 // register
832 // takes two arguments: an unsigned LEB128 constant representing a
833 // factored offset and a register number. The required action is to
834 // change the rule for the register indicated by the register number to
835 // be an offset(N) rule with a value of (N = factored offset *
836 // data_align).
837 uint8_t reg_num = extended_opcode;
838 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(offset_ptr: &offset) * data_align;
839 reg_location.SetAtCFAPlusOffset(op_offset);
840 row.SetRegisterInfo(reg_num, register_location: reg_location);
841 return true;
842 }
843 }
844 } else {
845 switch (extended_opcode) {
846 case DW_CFA_nop: // 0x0
847 return true;
848
849 case DW_CFA_offset_extended: // 0x5
850 {
851 // takes two unsigned LEB128 arguments representing a register number and
852 // a factored offset. This instruction is identical to DW_CFA_offset
853 // except for the encoding and size of the register argument.
854 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
855 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(offset_ptr: &offset) * data_align;
856 UnwindPlan::Row::RegisterLocation reg_location;
857 reg_location.SetAtCFAPlusOffset(op_offset);
858 row.SetRegisterInfo(reg_num, register_location: reg_location);
859 return true;
860 }
861
862 case DW_CFA_undefined: // 0x7
863 {
864 // takes a single unsigned LEB128 argument that represents a register
865 // number. The required action is to set the rule for the specified
866 // register to undefined.
867 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
868 UnwindPlan::Row::RegisterLocation reg_location;
869 reg_location.SetUndefined();
870 row.SetRegisterInfo(reg_num, register_location: reg_location);
871 return true;
872 }
873
874 case DW_CFA_same_value: // 0x8
875 {
876 // takes a single unsigned LEB128 argument that represents a register
877 // number. The required action is to set the rule for the specified
878 // register to same value.
879 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
880 UnwindPlan::Row::RegisterLocation reg_location;
881 reg_location.SetSame();
882 row.SetRegisterInfo(reg_num, register_location: reg_location);
883 return true;
884 }
885
886 case DW_CFA_register: // 0x9
887 {
888 // takes two unsigned LEB128 arguments representing register numbers. The
889 // required action is to set the rule for the first register to be the
890 // second register.
891 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
892 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
893 UnwindPlan::Row::RegisterLocation reg_location;
894 reg_location.SetInRegister(other_reg_num);
895 row.SetRegisterInfo(reg_num, register_location: reg_location);
896 return true;
897 }
898
899 case DW_CFA_def_cfa: // 0xC (CFA Definition Instruction)
900 {
901 // Takes two unsigned LEB128 operands representing a register number and
902 // a (non-factored) offset. The required action is to define the current
903 // CFA rule to use the provided register and offset.
904 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
905 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
906 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, offset: op_offset);
907 return true;
908 }
909
910 case DW_CFA_def_cfa_register: // 0xD (CFA Definition Instruction)
911 {
912 // takes a single unsigned LEB128 argument representing a register
913 // number. The required action is to define the current CFA rule to use
914 // the provided register (but to keep the old offset).
915 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
916 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num,
917 offset: row.GetCFAValue().GetOffset());
918 return true;
919 }
920
921 case DW_CFA_def_cfa_offset: // 0xE (CFA Definition Instruction)
922 {
923 // Takes a single unsigned LEB128 operand representing a (non-factored)
924 // offset. The required action is to define the current CFA rule to use
925 // the provided offset (but to keep the old register).
926 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
927 row.GetCFAValue().SetIsRegisterPlusOffset(
928 reg_num: row.GetCFAValue().GetRegisterNumber(), offset: op_offset);
929 return true;
930 }
931
932 case DW_CFA_def_cfa_expression: // 0xF (CFA Definition Instruction)
933 {
934 size_t block_len = (size_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
935 const uint8_t *block_data =
936 static_cast<const uint8_t *>(m_cfi_data.GetData(offset_ptr: &offset, length: block_len));
937 row.GetCFAValue().SetIsDWARFExpression(opcodes: block_data, len: block_len);
938 return true;
939 }
940
941 case DW_CFA_expression: // 0x10
942 {
943 // Takes two operands: an unsigned LEB128 value representing a register
944 // number, and a DW_FORM_block value representing a DWARF expression. The
945 // required action is to change the rule for the register indicated by
946 // the register number to be an expression(E) rule where E is the DWARF
947 // expression. That is, the DWARF expression computes the address. The
948 // value of the CFA is pushed on the DWARF evaluation stack prior to
949 // execution of the DWARF expression.
950 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
951 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
952 const uint8_t *block_data =
953 static_cast<const uint8_t *>(m_cfi_data.GetData(offset_ptr: &offset, length: block_len));
954 UnwindPlan::Row::RegisterLocation reg_location;
955 reg_location.SetAtDWARFExpression(opcodes: block_data, len: block_len);
956 row.SetRegisterInfo(reg_num, register_location: reg_location);
957 return true;
958 }
959
960 case DW_CFA_offset_extended_sf: // 0x11
961 {
962 // takes two operands: an unsigned LEB128 value representing a register
963 // number and a signed LEB128 factored offset. This instruction is
964 // identical to DW_CFA_offset_extended except that the second operand is
965 // signed and factored.
966 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
967 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(offset_ptr: &offset) * data_align;
968 UnwindPlan::Row::RegisterLocation reg_location;
969 reg_location.SetAtCFAPlusOffset(op_offset);
970 row.SetRegisterInfo(reg_num, register_location: reg_location);
971 return true;
972 }
973
974 case DW_CFA_def_cfa_sf: // 0x12 (CFA Definition Instruction)
975 {
976 // Takes two operands: an unsigned LEB128 value representing a register
977 // number and a signed LEB128 factored offset. This instruction is
978 // identical to DW_CFA_def_cfa except that the second operand is signed
979 // and factored.
980 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
981 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(offset_ptr: &offset) * data_align;
982 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, offset: op_offset);
983 return true;
984 }
985
986 case DW_CFA_def_cfa_offset_sf: // 0x13 (CFA Definition Instruction)
987 {
988 // takes a signed LEB128 operand representing a factored offset. This
989 // instruction is identical to DW_CFA_def_cfa_offset except that the
990 // operand is signed and factored.
991 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(offset_ptr: &offset) * data_align;
992 uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber();
993 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num: cfa_regnum, offset: op_offset);
994 return true;
995 }
996
997 case DW_CFA_val_expression: // 0x16
998 {
999 // takes two operands: an unsigned LEB128 value representing a register
1000 // number, and a DW_FORM_block value representing a DWARF expression. The
1001 // required action is to change the rule for the register indicated by
1002 // the register number to be a val_expression(E) rule where E is the
1003 // DWARF expression. That is, the DWARF expression computes the value of
1004 // the given register. The value of the CFA is pushed on the DWARF
1005 // evaluation stack prior to execution of the DWARF expression.
1006 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
1007 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(offset_ptr: &offset);
1008 const uint8_t *block_data =
1009 (const uint8_t *)m_cfi_data.GetData(offset_ptr: &offset, length: block_len);
1010 reg_location.SetIsDWARFExpression(opcodes: block_data, len: block_len);
1011 row.SetRegisterInfo(reg_num, register_location: reg_location);
1012 return true;
1013 }
1014 }
1015 }
1016 return false;
1017}
1018
1019void DWARFCallFrameInfo::ForEachFDEEntries(
1020 const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback) {
1021 GetFDEIndex();
1022
1023 for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) {
1024 const FDEEntryMap::Entry &entry = m_fde_index.GetEntryRef(i);
1025 if (!callback(entry.base, entry.size, entry.data))
1026 break;
1027 }
1028}
1029

source code of lldb/source/Symbol/DWARFCallFrameInfo.cpp