//===-- DWARFCallFrameInfo.cpp ----------------------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // C Includes // C++ Includes #include #include "lldb/Core/Log.h" #include "lldb/Core/Section.h" #include "lldb/Core/ArchSpec.h" #include "lldb/Core/Module.h" #include "lldb/Core/Section.h" #include "lldb/Core/Timer.h" #include "lldb/Host/Host.h" #include "lldb/Symbol/DWARFCallFrameInfo.h" #include "lldb/Symbol/ObjectFile.h" #include "lldb/Symbol/UnwindPlan.h" #include "lldb/Target/RegisterContext.h" #include "lldb/Target/Thread.h" using namespace lldb; using namespace lldb_private; DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile& objfile, SectionSP& section_sp, lldb::RegisterKind reg_kind, bool is_eh_frame) : m_objfile (objfile), m_section_sp (section_sp), m_reg_kind (reg_kind), // The flavor of registers that the CFI data uses (enum RegisterKind) m_flags (), m_cie_map (), m_cfi_data (), m_cfi_data_initialized (false), m_fde_index (), m_fde_index_initialized (false), m_is_eh_frame (is_eh_frame) { } DWARFCallFrameInfo::~DWARFCallFrameInfo() { } bool DWARFCallFrameInfo::GetUnwindPlan (Address addr, UnwindPlan& unwind_plan) { FDEEntryMap::Entry fde_entry; // Make sure that the Address we're searching for is the same object file // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index. ModuleSP module_sp = addr.GetModule(); if (module_sp.get() == NULL || module_sp->GetObjectFile() == NULL || module_sp->GetObjectFile() != &m_objfile) return false; if (GetFDEEntryByFileAddress (addr.GetFileAddress(), fde_entry) == false) return false; return FDEToUnwindPlan (fde_entry.data, addr, unwind_plan); } bool DWARFCallFrameInfo::GetAddressRange (Address addr, AddressRange &range) { // Make sure that the Address we're searching for is the same object file // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index. ModuleSP module_sp = addr.GetModule(); if (module_sp.get() == NULL || module_sp->GetObjectFile() == NULL || module_sp->GetObjectFile() != &m_objfile) return false; if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) return false; GetFDEIndex(); FDEEntryMap::Entry *fde_entry = m_fde_index.FindEntryThatContains (addr.GetFileAddress()); if (!fde_entry) return false; range = AddressRange(fde_entry->base, fde_entry->size, m_objfile.GetSectionList()); return true; } bool DWARFCallFrameInfo::GetFDEEntryByFileAddress (addr_t file_addr, FDEEntryMap::Entry &fde_entry) { if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) return false; GetFDEIndex(); if (m_fde_index.IsEmpty()) return false; FDEEntryMap::Entry *fde = m_fde_index.FindEntryThatContains (file_addr); if (fde == NULL) return false; fde_entry = *fde; return true; } void DWARFCallFrameInfo::GetFunctionAddressAndSizeVector (FunctionAddressAndSizeVector &function_info) { GetFDEIndex(); const size_t count = m_fde_index.GetSize(); function_info.Clear(); if (count > 0) function_info.Reserve(count); for (size_t i = 0; i < count; ++i) { const FDEEntryMap::Entry *func_offset_data_entry = m_fde_index.GetEntryAtIndex (i); if (func_offset_data_entry) { FunctionAddressAndSizeVector::Entry function_offset_entry (func_offset_data_entry->base, func_offset_data_entry->size); function_info.Append (function_offset_entry); } } } const DWARFCallFrameInfo::CIE* DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) { cie_map_t::iterator pos = m_cie_map.find(cie_offset); if (pos != m_cie_map.end()) { // Parse and cache the CIE if (pos->second.get() == NULL) pos->second = ParseCIE (cie_offset); return pos->second.get(); } return NULL; } DWARFCallFrameInfo::CIESP DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset) { CIESP cie_sp(new CIE(cie_offset)); lldb::offset_t offset = cie_offset; if (m_cfi_data_initialized == false) GetCFIData(); const uint32_t length = m_cfi_data.GetU32(&offset); const dw_offset_t cie_id = m_cfi_data.GetU32(&offset); const dw_offset_t end_offset = cie_offset + length + 4; if (length > 0 && ((!m_is_eh_frame && cie_id == UINT32_MAX) || (m_is_eh_frame && cie_id == 0ul))) { size_t i; // cie.offset = cie_offset; // cie.length = length; // cie.cieID = cieID; cie_sp->ptr_encoding = DW_EH_PE_absptr; // default cie_sp->version = m_cfi_data.GetU8(&offset); for (i=0; iaugmentation[i] = m_cfi_data.GetU8(&offset); if (cie_sp->augmentation[i] == '\0') { // Zero out remaining bytes in augmentation string for (size_t j = i+1; jaugmentation[j] = '\0'; break; } } if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0') { 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); return cie_sp; } cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); if (cie_sp->augmentation[0]) { // Get the length of the eh_frame augmentation data // which starts with a ULEB128 length in bytes const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); const size_t aug_data_end = offset + aug_data_len; const size_t aug_str_len = strlen(cie_sp->augmentation); // A 'z' may be present as the first character of the string. // If present, the Augmentation Data field shall be present. // The contents of the Augmentation Data shall be intepreted // according to other characters in the Augmentation String. if (cie_sp->augmentation[0] == 'z') { // Extract the Augmentation Data size_t aug_str_idx = 0; for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) { char aug = cie_sp->augmentation[aug_str_idx]; switch (aug) { case 'L': // Indicates the presence of one argument in the // Augmentation Data of the CIE, and a corresponding // argument in the Augmentation Data of the FDE. The // argument in the Augmentation Data of the CIE is // 1-byte and represents the pointer encoding used // for the argument in the Augmentation Data of the // FDE, which is the address of a language-specific // data area (LSDA). The size of the LSDA pointer is // specified by the pointer encoding used. m_cfi_data.GetU8(&offset); break; case 'P': // Indicates the presence of two arguments in the // Augmentation Data of the cie_sp-> The first argument // is 1-byte and represents the pointer encoding // used for the second argument, which is the // address of a personality routine handler. The // size of the personality routine pointer is // specified by the pointer encoding used. { uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); } break; case 'R': // A 'R' may be present at any position after the // first character of the string. The Augmentation // Data shall include a 1 byte argument that // represents the pointer encoding for the address // pointers used in the FDE. // Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); break; } } } else if (strcmp(cie_sp->augmentation, "eh") == 0) { // If the Augmentation string has the value "eh", then // the EH Data field shall be present } // Set the offset to be the end of the augmentation data just in case // we didn't understand any of the data. offset = (uint32_t)aug_data_end; } if (end_offset > offset) { cie_sp->inst_offset = offset; cie_sp->inst_length = end_offset - offset; } while (offset < end_offset) { uint8_t inst = m_cfi_data.GetU8(&offset); uint8_t primary_opcode = inst & 0xC0; uint8_t extended_opcode = inst & 0x3F; if (extended_opcode == DW_CFA_def_cfa) { // Takes two unsigned LEB128 operands representing a register // number and a (non-factored) offset. The required action // is to define the current CFA rule to use the provided // register and offset. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); cie_sp->initial_row.SetCFARegister (reg_num); cie_sp->initial_row.SetCFAOffset (op_offset); continue; } if (primary_opcode == DW_CFA_offset) { // 0x80 - high 2 bits are 0x2, lower 6 bits are register. // Takes two arguments: an unsigned LEB128 constant representing a // factored offset and a register number. The required action is to // change the rule for the register indicated by the register number // to be an offset(N) rule with a value of // (N = factored offset * data_align). uint32_t reg_num = extended_opcode; int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetAtCFAPlusOffset(op_offset); cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); continue; } if (extended_opcode == DW_CFA_nop) { continue; } break; // Stop if we hit an unrecognized opcode } } return cie_sp; } void DWARFCallFrameInfo::GetCFIData() { if (m_cfi_data_initialized == false) { Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); if (log) m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); m_cfi_data_initialized = true; } } // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses // of the functions and a pointer back to the function's FDE for later expansion. // Internalize CIEs as we come across them. void DWARFCallFrameInfo::GetFDEIndex () { if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) return; if (m_fde_index_initialized) return; Mutex::Locker locker(m_fde_index_mutex); if (m_fde_index_initialized) // if two threads hit the locker return; Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); lldb::offset_t offset = 0; if (m_cfi_data_initialized == false) GetCFIData(); while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) { const dw_offset_t current_entry = offset; uint32_t len = m_cfi_data.GetU32 (&offset); dw_offset_t next_entry = current_entry + len + 4; dw_offset_t cie_id = m_cfi_data.GetU32 (&offset); if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) { m_cie_map[current_entry] = ParseCIE (current_entry); offset = next_entry; continue; } const dw_offset_t cie_offset = current_entry + 4 - cie_id; const CIE *cie = GetCIE (cie_offset); if (cie) { const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); FDEEntryMap::Entry fde (addr, length, current_entry); m_fde_index.Append(fde); } else { Host::SystemLog (Host::eSystemLogError, "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", cie_offset, cie_id, current_entry); } offset = next_entry; } m_fde_index.Sort(); m_fde_index_initialized = true; } bool DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) { lldb::offset_t offset = dwarf_offset; lldb::offset_t current_entry = offset; if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) return false; if (m_cfi_data_initialized == false) GetCFIData(); uint32_t length = m_cfi_data.GetU32 (&offset); dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset); assert (cie_offset != 0 && cie_offset != UINT32_MAX); // Translate the CIE_id from the eh_frame format, which // is relative to the FDE offset, into a __eh_frame section // offset if (m_is_eh_frame) { unwind_plan.SetSourceName ("eh_frame CFI"); cie_offset = current_entry + 4 - cie_offset; unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); } else { unwind_plan.SetSourceName ("DWARF CFI"); // In theory the debug_frame info should be valid at all call sites // ("asynchronous unwind info" as it is sometimes called) but in practice // gcc et al all emit call frame info for the prologue and call sites, but // not for the epilogue or all the other locations during the function reliably. unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); } unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); const CIE *cie = GetCIE (cie_offset); assert (cie != NULL); const dw_offset_t end_offset = current_entry + length + 4; const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 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); AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); range.SetByteSize (range_len); if (cie->augmentation[0] == 'z') { uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); offset += aug_data_len; } uint32_t reg_num = 0; int32_t op_offset = 0; uint32_t code_align = cie->code_align; int32_t data_align = cie->data_align; unwind_plan.SetPlanValidAddressRange (range); UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; *cie_initial_row = cie->initial_row; UnwindPlan::RowSP row(cie_initial_row); unwind_plan.SetRegisterKind (m_reg_kind); unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); std::vector stack; UnwindPlan::Row::RegisterLocation reg_location; while (m_cfi_data.ValidOffset(offset) && offset < end_offset) { uint8_t inst = m_cfi_data.GetU8(&offset); uint8_t primary_opcode = inst & 0xC0; uint8_t extended_opcode = inst & 0x3F; if (primary_opcode) { switch (primary_opcode) { case DW_CFA_advance_loc : // (Row Creation Instruction) { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta // takes a single argument that represents a constant delta. The // required action is to create a new table row with a location // value that is computed by taking the current entry's location // value and adding (delta * code_align). All other // values in the new row are initially identical to the current row. unwind_plan.AppendRow(row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); row->SlideOffset(extended_opcode * code_align); } break; case DW_CFA_offset : { // 0x80 - high 2 bits are 0x2, lower 6 bits are register // takes two arguments: an unsigned LEB128 constant representing a // factored offset and a register number. The required action is to // change the rule for the register indicated by the register number // to be an offset(N) rule with a value of // (N = factored offset * data_align). reg_num = extended_opcode; op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; reg_location.SetAtCFAPlusOffset(op_offset); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_restore : { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register // takes a single argument that represents a register number. The // required action is to change the rule for the indicated register // to the rule assigned it by the initial_instructions in the CIE. reg_num = extended_opcode; // We only keep enough register locations around to // unwind what is in our thread, and these are organized // by the register index in that state, so we need to convert our // GCC register number from the EH frame info, to a register index if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) row->SetRegisterInfo (reg_num, reg_location); } break; } } else { switch (extended_opcode) { case DW_CFA_nop : // 0x0 break; case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) { // DW_CFA_set_loc takes a single argument that represents an address. // The required action is to create a new table row using the // specified address as the location. All other values in the new row // are initially identical to the current row. The new location value // should always be greater than the current one. unwind_plan.AppendRow(row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); } break; case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) { // takes a single uword argument that represents a constant delta. // This instruction is identical to DW_CFA_advance_loc except for the // encoding and size of the delta argument. unwind_plan.AppendRow(row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); } break; case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) { // takes a single uword argument that represents a constant delta. // This instruction is identical to DW_CFA_advance_loc except for the // encoding and size of the delta argument. unwind_plan.AppendRow(row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); } break; case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) { // takes a single uword argument that represents a constant delta. // This instruction is identical to DW_CFA_advance_loc except for the // encoding and size of the delta argument. unwind_plan.AppendRow(row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); } break; case DW_CFA_offset_extended : // 0x5 { // takes two unsigned LEB128 arguments representing a register number // and a factored offset. This instruction is identical to DW_CFA_offset // except for the encoding and size of the register argument. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; reg_location.SetAtCFAPlusOffset(op_offset); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_restore_extended : // 0x6 { // takes a single unsigned LEB128 argument that represents a register // number. This instruction is identical to DW_CFA_restore except for // the encoding and size of the register argument. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_undefined : // 0x7 { // takes a single unsigned LEB128 argument that represents a register // number. The required action is to set the rule for the specified // register to undefined. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); reg_location.SetUndefined(); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_same_value : // 0x8 { // takes a single unsigned LEB128 argument that represents a register // number. The required action is to set the rule for the specified // register to same value. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); reg_location.SetSame(); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_register : // 0x9 { // takes two unsigned LEB128 arguments representing register numbers. // The required action is to set the rule for the first register to be // the second register. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); reg_location.SetInRegister(other_reg_num); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_remember_state : // 0xA { // These instructions define a stack of information. Encountering the // DW_CFA_remember_state instruction means to save the rules for every // register on the current row on the stack. Encountering the // DW_CFA_restore_state instruction means to pop the set of rules off // the stack and place them in the current row. (This operation is // useful for compilers that move epilogue code into the body of a // function.) stack.push_back (row); UnwindPlan::Row *newrow = new UnwindPlan::Row; *newrow = *row.get(); row.reset (newrow); } break; case DW_CFA_restore_state : // 0xB // These instructions define a stack of information. Encountering the // DW_CFA_remember_state instruction means to save the rules for every // register on the current row on the stack. Encountering the // DW_CFA_restore_state instruction means to pop the set of rules off // the stack and place them in the current row. (This operation is // useful for compilers that move epilogue code into the body of a // function.) { row = stack.back (); stack.pop_back (); } break; case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) { // Takes two unsigned LEB128 operands representing a register // number and a (non-factored) offset. The required action // is to define the current CFA rule to use the provided // register and offset. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); row->SetCFARegister (reg_num); row->SetCFAOffset (op_offset); } break; case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) { // takes a single unsigned LEB128 argument representing a register // number. The required action is to define the current CFA rule to // use the provided register (but to keep the old offset). reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); row->SetCFARegister (reg_num); } break; case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) { // Takes a single unsigned LEB128 operand representing a // (non-factored) offset. The required action is to define // the current CFA rule to use the provided offset (but // to keep the old register). op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); row->SetCFAOffset (op_offset); } break; case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) { size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); offset += (uint32_t)block_len; } break; case DW_CFA_expression : // 0x10 { // Takes two operands: an unsigned LEB128 value representing // a register number, and a DW_FORM_block value representing a DWARF // expression. The required action is to change the rule for the // register indicated by the register number to be an expression(E) // rule where E is the DWARF expression. That is, the DWARF // expression computes the address. The value of the CFA is // pushed on the DWARF evaluation stack prior to execution of // the DWARF expression. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); reg_location.SetAtDWARFExpression(block_data, block_len); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_offset_extended_sf : // 0x11 { // takes two operands: an unsigned LEB128 value representing a // register number and a signed LEB128 factored offset. This // instruction is identical to DW_CFA_offset_extended except //that the second operand is signed and factored. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; reg_location.SetAtCFAPlusOffset(op_offset); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) { // Takes two operands: an unsigned LEB128 value representing // a register number and a signed LEB128 factored offset. // This instruction is identical to DW_CFA_def_cfa except // that the second operand is signed and factored. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; row->SetCFARegister (reg_num); row->SetCFAOffset (op_offset); } break; case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) { // takes a signed LEB128 operand representing a factored // offset. This instruction is identical to DW_CFA_def_cfa_offset // except that the operand is signed and factored. op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; row->SetCFAOffset (op_offset); } break; case DW_CFA_val_expression : // 0x16 { // takes two operands: an unsigned LEB128 value representing a register // number, and a DW_FORM_block value representing a DWARF expression. // The required action is to change the rule for the register indicated // by the register number to be a val_expression(E) rule where E is the // DWARF expression. That is, the DWARF expression computes the value of // the given register. The value of the CFA is pushed on the DWARF // evaluation stack prior to execution of the DWARF expression. reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); //#if defined(__i386__) || defined(__x86_64__) // // The EH frame info for EIP and RIP contains code that looks for traps to // // be a specific type and increments the PC. // // For i386: // // DW_CFA_val_expression where: // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, // // DW_OP_and, DW_OP_plus // // This basically does a: // // eip = ucontenxt.mcontext32->gpr.eip; // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) // // eip++; // // // // For x86_64: // // DW_CFA_val_expression where: // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus // // This basically does a: // // rip = ucontenxt.mcontext64->gpr.rip; // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) // // rip++; // // The trap comparisons and increments are not needed as it hoses up the unwound PC which // // is expected to point at least past the instruction that causes the fault/trap. So we // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) // { // if (thread->Is64Bit()) // { // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) // block_len = 8; // } // else // { // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) // block_len = 7; // } // } //#endif reg_location.SetIsDWARFExpression(block_data, block_len); row->SetRegisterInfo (reg_num, reg_location); } break; case DW_CFA_val_offset : // 0x14 case DW_CFA_val_offset_sf : // 0x15 default: break; } } } unwind_plan.AppendRow(row); return true; }