1 //===-- DWARFCallFrameInfo.cpp ----------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
15 #include "lldb/Core/Log.h"
16 #include "lldb/Core/Section.h"
17 #include "lldb/Core/ArchSpec.h"
18 #include "lldb/Core/Module.h"
19 #include "lldb/Core/Section.h"
20 #include "lldb/Core/Timer.h"
21 #include "lldb/Host/Host.h"
22 #include "lldb/Symbol/DWARFCallFrameInfo.h"
23 #include "lldb/Symbol/ObjectFile.h"
24 #include "lldb/Symbol/UnwindPlan.h"
25 #include "lldb/Target/RegisterContext.h"
26 #include "lldb/Target/Thread.h"
29 using namespace lldb_private;
31 DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile& objfile, SectionSP& section_sp, lldb::RegisterKind reg_kind, bool is_eh_frame) :
33 m_section_sp (section_sp),
34 m_reg_kind (reg_kind), // The flavor of registers that the CFI data uses (enum RegisterKind)
38 m_cfi_data_initialized (false),
40 m_fde_index_initialized (false),
41 m_is_eh_frame (is_eh_frame)
45 DWARFCallFrameInfo::~DWARFCallFrameInfo()
51 DWARFCallFrameInfo::GetUnwindPlan (Address addr, UnwindPlan& unwind_plan)
53 FDEEntryMap::Entry fde_entry;
55 // Make sure that the Address we're searching for is the same object file
56 // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index.
57 ModuleSP module_sp = addr.GetModule();
58 if (module_sp.get() == NULL || module_sp->GetObjectFile() == NULL || module_sp->GetObjectFile() != &m_objfile)
61 if (GetFDEEntryByFileAddress (addr.GetFileAddress(), fde_entry) == false)
63 return FDEToUnwindPlan (fde_entry.data, addr, unwind_plan);
67 DWARFCallFrameInfo::GetAddressRange (Address addr, AddressRange &range)
70 // Make sure that the Address we're searching for is the same object file
71 // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index.
72 ModuleSP module_sp = addr.GetModule();
73 if (module_sp.get() == NULL || module_sp->GetObjectFile() == NULL || module_sp->GetObjectFile() != &m_objfile)
76 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted())
79 FDEEntryMap::Entry *fde_entry = m_fde_index.FindEntryThatContains (addr.GetFileAddress());
83 range = AddressRange(fde_entry->base, fde_entry->size, m_objfile.GetSectionList());
88 DWARFCallFrameInfo::GetFDEEntryByFileAddress (addr_t file_addr, FDEEntryMap::Entry &fde_entry)
90 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted())
95 if (m_fde_index.IsEmpty())
98 FDEEntryMap::Entry *fde = m_fde_index.FindEntryThatContains (file_addr);
108 DWARFCallFrameInfo::GetFunctionAddressAndSizeVector (FunctionAddressAndSizeVector &function_info)
111 const size_t count = m_fde_index.GetSize();
112 function_info.Clear();
114 function_info.Reserve(count);
115 for (size_t i = 0; i < count; ++i)
117 const FDEEntryMap::Entry *func_offset_data_entry = m_fde_index.GetEntryAtIndex (i);
118 if (func_offset_data_entry)
120 FunctionAddressAndSizeVector::Entry function_offset_entry (func_offset_data_entry->base, func_offset_data_entry->size);
121 function_info.Append (function_offset_entry);
126 const DWARFCallFrameInfo::CIE*
127 DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset)
129 cie_map_t::iterator pos = m_cie_map.find(cie_offset);
131 if (pos != m_cie_map.end())
133 // Parse and cache the CIE
134 if (pos->second.get() == NULL)
135 pos->second = ParseCIE (cie_offset);
137 return pos->second.get();
142 DWARFCallFrameInfo::CIESP
143 DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset)
145 CIESP cie_sp(new CIE(cie_offset));
146 lldb::offset_t offset = cie_offset;
147 if (m_cfi_data_initialized == false)
149 const uint32_t length = m_cfi_data.GetU32(&offset);
150 const dw_offset_t cie_id = m_cfi_data.GetU32(&offset);
151 const dw_offset_t end_offset = cie_offset + length + 4;
152 if (length > 0 && ((!m_is_eh_frame && cie_id == UINT32_MAX) || (m_is_eh_frame && cie_id == 0ul)))
155 // cie.offset = cie_offset;
156 // cie.length = length;
157 // cie.cieID = cieID;
158 cie_sp->ptr_encoding = DW_EH_PE_absptr; // default
159 cie_sp->version = m_cfi_data.GetU8(&offset);
161 for (i=0; i<CFI_AUG_MAX_SIZE; ++i)
163 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset);
164 if (cie_sp->augmentation[i] == '\0')
166 // Zero out remaining bytes in augmentation string
167 for (size_t j = i+1; j<CFI_AUG_MAX_SIZE; ++j)
168 cie_sp->augmentation[j] = '\0';
174 if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0')
176 Host::SystemLog (Host::eSystemLogError, "CIE parse error: CIE augmentation string was too large for the fixed sized buffer of %d bytes.\n", CFI_AUG_MAX_SIZE);
179 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset);
180 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset);
181 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset);
183 if (cie_sp->augmentation[0])
185 // Get the length of the eh_frame augmentation data
186 // which starts with a ULEB128 length in bytes
187 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset);
188 const size_t aug_data_end = offset + aug_data_len;
189 const size_t aug_str_len = strlen(cie_sp->augmentation);
190 // A 'z' may be present as the first character of the string.
191 // If present, the Augmentation Data field shall be present.
192 // The contents of the Augmentation Data shall be intepreted
193 // according to other characters in the Augmentation String.
194 if (cie_sp->augmentation[0] == 'z')
196 // Extract the Augmentation Data
197 size_t aug_str_idx = 0;
198 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++)
200 char aug = cie_sp->augmentation[aug_str_idx];
204 // Indicates the presence of one argument in the
205 // Augmentation Data of the CIE, and a corresponding
206 // argument in the Augmentation Data of the FDE. The
207 // argument in the Augmentation Data of the CIE is
208 // 1-byte and represents the pointer encoding used
209 // for the argument in the Augmentation Data of the
210 // FDE, which is the address of a language-specific
211 // data area (LSDA). The size of the LSDA pointer is
212 // specified by the pointer encoding used.
213 m_cfi_data.GetU8(&offset);
217 // Indicates the presence of two arguments in the
218 // Augmentation Data of the cie_sp-> The first argument
219 // is 1-byte and represents the pointer encoding
220 // used for the second argument, which is the
221 // address of a personality routine handler. The
222 // size of the personality routine pointer is
223 // specified by the pointer encoding used.
225 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset);
226 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS);
231 // A 'R' may be present at any position after the
232 // first character of the string. The Augmentation
233 // Data shall include a 1 byte argument that
234 // represents the pointer encoding for the address
235 // pointers used in the FDE.
236 // Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4
237 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset);
242 else if (strcmp(cie_sp->augmentation, "eh") == 0)
244 // If the Augmentation string has the value "eh", then
245 // the EH Data field shall be present
248 // Set the offset to be the end of the augmentation data just in case
249 // we didn't understand any of the data.
250 offset = (uint32_t)aug_data_end;
253 if (end_offset > offset)
255 cie_sp->inst_offset = offset;
256 cie_sp->inst_length = end_offset - offset;
258 while (offset < end_offset)
260 uint8_t inst = m_cfi_data.GetU8(&offset);
261 uint8_t primary_opcode = inst & 0xC0;
262 uint8_t extended_opcode = inst & 0x3F;
264 if (extended_opcode == DW_CFA_def_cfa)
266 // Takes two unsigned LEB128 operands representing a register
267 // number and a (non-factored) offset. The required action
268 // is to define the current CFA rule to use the provided
269 // register and offset.
270 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
271 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset);
272 cie_sp->initial_row.SetCFARegister (reg_num);
273 cie_sp->initial_row.SetCFAOffset (op_offset);
276 if (primary_opcode == DW_CFA_offset)
278 // 0x80 - high 2 bits are 0x2, lower 6 bits are register.
279 // Takes two arguments: an unsigned LEB128 constant representing a
280 // factored offset and a register number. The required action is to
281 // change the rule for the register indicated by the register number
282 // to be an offset(N) rule with a value of
283 // (N = factored offset * data_align).
284 uint32_t reg_num = extended_opcode;
285 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align;
286 UnwindPlan::Row::RegisterLocation reg_location;
287 reg_location.SetAtCFAPlusOffset(op_offset);
288 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location);
291 if (extended_opcode == DW_CFA_nop)
295 break; // Stop if we hit an unrecognized opcode
303 DWARFCallFrameInfo::GetCFIData()
305 if (m_cfi_data_initialized == false)
307 Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
309 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info");
310 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data);
311 m_cfi_data_initialized = true;
314 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses
315 // of the functions and a pointer back to the function's FDE for later expansion.
316 // Internalize CIEs as we come across them.
319 DWARFCallFrameInfo::GetFDEIndex ()
321 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted())
324 if (m_fde_index_initialized)
327 Mutex::Locker locker(m_fde_index_mutex);
329 if (m_fde_index_initialized) // if two threads hit the locker
332 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString(""));
334 lldb::offset_t offset = 0;
335 if (m_cfi_data_initialized == false)
337 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8))
339 const dw_offset_t current_entry = offset;
340 uint32_t len = m_cfi_data.GetU32 (&offset);
341 dw_offset_t next_entry = current_entry + len + 4;
342 dw_offset_t cie_id = m_cfi_data.GetU32 (&offset);
344 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0)
346 m_cie_map[current_entry] = ParseCIE (current_entry);
351 const dw_offset_t cie_offset = current_entry + 4 - cie_id;
352 const CIE *cie = GetCIE (cie_offset);
355 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
356 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
357 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
359 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr);
360 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr);
361 FDEEntryMap::Entry fde (addr, length, current_entry);
362 m_fde_index.Append(fde);
366 Host::SystemLog (Host::eSystemLogError,
367 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n",
375 m_fde_index_initialized = true;
379 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan)
381 lldb::offset_t offset = dwarf_offset;
382 lldb::offset_t current_entry = offset;
384 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted())
387 if (m_cfi_data_initialized == false)
390 uint32_t length = m_cfi_data.GetU32 (&offset);
391 dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset);
393 assert (cie_offset != 0 && cie_offset != UINT32_MAX);
395 // Translate the CIE_id from the eh_frame format, which
396 // is relative to the FDE offset, into a __eh_frame section
400 unwind_plan.SetSourceName ("eh_frame CFI");
401 cie_offset = current_entry + 4 - cie_offset;
402 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
406 unwind_plan.SetSourceName ("DWARF CFI");
407 // In theory the debug_frame info should be valid at all call sites
408 // ("asynchronous unwind info" as it is sometimes called) but in practice
409 // gcc et al all emit call frame info for the prologue and call sites, but
410 // not for the epilogue or all the other locations during the function reliably.
411 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
413 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes);
415 const CIE *cie = GetCIE (cie_offset);
416 assert (cie != NULL);
418 const dw_offset_t end_offset = current_entry + length + 4;
420 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
421 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
422 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
423 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr);
424 lldb::addr_t range_len = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr);
425 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList());
426 range.SetByteSize (range_len);
428 if (cie->augmentation[0] == 'z')
430 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
431 offset += aug_data_len;
434 uint32_t reg_num = 0;
435 int32_t op_offset = 0;
436 uint32_t code_align = cie->code_align;
437 int32_t data_align = cie->data_align;
439 unwind_plan.SetPlanValidAddressRange (range);
440 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row;
441 *cie_initial_row = cie->initial_row;
442 UnwindPlan::RowSP row(cie_initial_row);
444 unwind_plan.SetRegisterKind (m_reg_kind);
445 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num);
447 std::vector<UnwindPlan::RowSP> stack;
449 UnwindPlan::Row::RegisterLocation reg_location;
450 while (m_cfi_data.ValidOffset(offset) && offset < end_offset)
452 uint8_t inst = m_cfi_data.GetU8(&offset);
453 uint8_t primary_opcode = inst & 0xC0;
454 uint8_t extended_opcode = inst & 0x3F;
458 switch (primary_opcode)
460 case DW_CFA_advance_loc : // (Row Creation Instruction)
461 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta
462 // takes a single argument that represents a constant delta. The
463 // required action is to create a new table row with a location
464 // value that is computed by taking the current entry's location
465 // value and adding (delta * code_align). All other
466 // values in the new row are initially identical to the current row.
467 unwind_plan.AppendRow(row);
468 UnwindPlan::Row *newrow = new UnwindPlan::Row;
469 *newrow = *row.get();
471 row->SlideOffset(extended_opcode * code_align);
476 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register
477 // takes two arguments: an unsigned LEB128 constant representing a
478 // factored offset and a register number. The required action is to
479 // change the rule for the register indicated by the register number
480 // to be an offset(N) rule with a value of
481 // (N = factored offset * data_align).
482 reg_num = extended_opcode;
483 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align;
484 reg_location.SetAtCFAPlusOffset(op_offset);
485 row->SetRegisterInfo (reg_num, reg_location);
489 case DW_CFA_restore :
490 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register
491 // takes a single argument that represents a register number. The
492 // required action is to change the rule for the indicated register
493 // to the rule assigned it by the initial_instructions in the CIE.
494 reg_num = extended_opcode;
495 // We only keep enough register locations around to
496 // unwind what is in our thread, and these are organized
497 // by the register index in that state, so we need to convert our
498 // GCC register number from the EH frame info, to a register index
500 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
501 row->SetRegisterInfo (reg_num, reg_location);
508 switch (extended_opcode)
510 case DW_CFA_nop : // 0x0
513 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction)
515 // DW_CFA_set_loc takes a single argument that represents an address.
516 // The required action is to create a new table row using the
517 // specified address as the location. All other values in the new row
518 // are initially identical to the current row. The new location value
519 // should always be greater than the current one.
520 unwind_plan.AppendRow(row);
521 UnwindPlan::Row *newrow = new UnwindPlan::Row;
522 *newrow = *row.get();
524 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress());
528 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction)
530 // takes a single uword argument that represents a constant delta.
531 // This instruction is identical to DW_CFA_advance_loc except for the
532 // encoding and size of the delta argument.
533 unwind_plan.AppendRow(row);
534 UnwindPlan::Row *newrow = new UnwindPlan::Row;
535 *newrow = *row.get();
537 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align);
541 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction)
543 // takes a single uword argument that represents a constant delta.
544 // This instruction is identical to DW_CFA_advance_loc except for the
545 // encoding and size of the delta argument.
546 unwind_plan.AppendRow(row);
547 UnwindPlan::Row *newrow = new UnwindPlan::Row;
548 *newrow = *row.get();
550 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align);
554 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction)
556 // takes a single uword argument that represents a constant delta.
557 // This instruction is identical to DW_CFA_advance_loc except for the
558 // encoding and size of the delta argument.
559 unwind_plan.AppendRow(row);
560 UnwindPlan::Row *newrow = new UnwindPlan::Row;
561 *newrow = *row.get();
563 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align);
567 case DW_CFA_offset_extended : // 0x5
569 // takes two unsigned LEB128 arguments representing a register number
570 // and a factored offset. This instruction is identical to DW_CFA_offset
571 // except for the encoding and size of the register argument.
572 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
573 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align;
574 reg_location.SetAtCFAPlusOffset(op_offset);
575 row->SetRegisterInfo (reg_num, reg_location);
579 case DW_CFA_restore_extended : // 0x6
581 // takes a single unsigned LEB128 argument that represents a register
582 // number. This instruction is identical to DW_CFA_restore except for
583 // the encoding and size of the register argument.
584 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
585 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
586 row->SetRegisterInfo (reg_num, reg_location);
590 case DW_CFA_undefined : // 0x7
592 // takes a single unsigned LEB128 argument that represents a register
593 // number. The required action is to set the rule for the specified
594 // register to undefined.
595 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
596 reg_location.SetUndefined();
597 row->SetRegisterInfo (reg_num, reg_location);
601 case DW_CFA_same_value : // 0x8
603 // takes a single unsigned LEB128 argument that represents a register
604 // number. The required action is to set the rule for the specified
605 // register to same value.
606 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
607 reg_location.SetSame();
608 row->SetRegisterInfo (reg_num, reg_location);
612 case DW_CFA_register : // 0x9
614 // takes two unsigned LEB128 arguments representing register numbers.
615 // The required action is to set the rule for the first register to be
616 // the second register.
618 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
619 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
620 reg_location.SetInRegister(other_reg_num);
621 row->SetRegisterInfo (reg_num, reg_location);
625 case DW_CFA_remember_state : // 0xA
627 // These instructions define a stack of information. Encountering the
628 // DW_CFA_remember_state instruction means to save the rules for every
629 // register on the current row on the stack. Encountering the
630 // DW_CFA_restore_state instruction means to pop the set of rules off
631 // the stack and place them in the current row. (This operation is
632 // useful for compilers that move epilogue code into the body of a
634 stack.push_back (row);
635 UnwindPlan::Row *newrow = new UnwindPlan::Row;
636 *newrow = *row.get();
641 case DW_CFA_restore_state : // 0xB
642 // These instructions define a stack of information. Encountering the
643 // DW_CFA_remember_state instruction means to save the rules for every
644 // register on the current row on the stack. Encountering the
645 // DW_CFA_restore_state instruction means to pop the set of rules off
646 // the stack and place them in the current row. (This operation is
647 // useful for compilers that move epilogue code into the body of a
655 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction)
657 // Takes two unsigned LEB128 operands representing a register
658 // number and a (non-factored) offset. The required action
659 // is to define the current CFA rule to use the provided
660 // register and offset.
661 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
662 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset);
663 row->SetCFARegister (reg_num);
664 row->SetCFAOffset (op_offset);
668 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction)
670 // takes a single unsigned LEB128 argument representing a register
671 // number. The required action is to define the current CFA rule to
672 // use the provided register (but to keep the old offset).
673 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
674 row->SetCFARegister (reg_num);
678 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction)
680 // Takes a single unsigned LEB128 operand representing a
681 // (non-factored) offset. The required action is to define
682 // the current CFA rule to use the provided offset (but
683 // to keep the old register).
684 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset);
685 row->SetCFAOffset (op_offset);
689 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction)
691 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset);
692 offset += (uint32_t)block_len;
696 case DW_CFA_expression : // 0x10
698 // Takes two operands: an unsigned LEB128 value representing
699 // a register number, and a DW_FORM_block value representing a DWARF
700 // expression. The required action is to change the rule for the
701 // register indicated by the register number to be an expression(E)
702 // rule where E is the DWARF expression. That is, the DWARF
703 // expression computes the address. The value of the CFA is
704 // pushed on the DWARF evaluation stack prior to execution of
705 // the DWARF expression.
706 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
707 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
708 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len);
710 reg_location.SetAtDWARFExpression(block_data, block_len);
711 row->SetRegisterInfo (reg_num, reg_location);
715 case DW_CFA_offset_extended_sf : // 0x11
717 // takes two operands: an unsigned LEB128 value representing a
718 // register number and a signed LEB128 factored offset. This
719 // instruction is identical to DW_CFA_offset_extended except
720 //that the second operand is signed and factored.
721 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
722 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
723 reg_location.SetAtCFAPlusOffset(op_offset);
724 row->SetRegisterInfo (reg_num, reg_location);
728 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction)
730 // Takes two operands: an unsigned LEB128 value representing
731 // a register number and a signed LEB128 factored offset.
732 // This instruction is identical to DW_CFA_def_cfa except
733 // that the second operand is signed and factored.
734 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
735 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
736 row->SetCFARegister (reg_num);
737 row->SetCFAOffset (op_offset);
741 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction)
743 // takes a signed LEB128 operand representing a factored
744 // offset. This instruction is identical to DW_CFA_def_cfa_offset
745 // except that the operand is signed and factored.
746 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
747 row->SetCFAOffset (op_offset);
751 case DW_CFA_val_expression : // 0x16
753 // takes two operands: an unsigned LEB128 value representing a register
754 // number, and a DW_FORM_block value representing a DWARF expression.
755 // The required action is to change the rule for the register indicated
756 // by the register number to be a val_expression(E) rule where E is the
757 // DWARF expression. That is, the DWARF expression computes the value of
758 // the given register. The value of the CFA is pushed on the DWARF
759 // evaluation stack prior to execution of the DWARF expression.
760 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
761 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
762 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len);
763 //#if defined(__i386__) || defined(__x86_64__)
764 // // The EH frame info for EIP and RIP contains code that looks for traps to
765 // // be a specific type and increments the PC.
767 // // DW_CFA_val_expression where:
768 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34),
769 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref,
770 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne,
771 // // DW_OP_and, DW_OP_plus
772 // // This basically does a:
773 // // eip = ucontenxt.mcontext32->gpr.eip;
774 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4)
778 // // DW_CFA_val_expression where:
779 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref,
780 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3,
781 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus
782 // // This basically does a:
783 // // rip = ucontenxt.mcontext64->gpr.rip;
784 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4)
786 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which
787 // // is expected to point at least past the instruction that causes the fault/trap. So we
788 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes
789 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num)
791 // if (thread->Is64Bit())
793 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst)
798 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst)
803 reg_location.SetIsDWARFExpression(block_data, block_len);
804 row->SetRegisterInfo (reg_num, reg_location);
808 case DW_CFA_val_offset : // 0x14
809 case DW_CFA_val_offset_sf : // 0x15
815 unwind_plan.AppendRow(row);