//===-- DWARFCallFrameInfo.cpp --------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "lldb/Symbol/DWARFCallFrameInfo.h" #include "lldb/Core/Module.h" #include "lldb/Core/Section.h" #include "lldb/Core/dwarf.h" #include "lldb/Host/Host.h" #include "lldb/Symbol/ObjectFile.h" #include "lldb/Symbol/UnwindPlan.h" #include "lldb/Target/RegisterContext.h" #include "lldb/Target/Thread.h" #include "lldb/Utility/ArchSpec.h" #include "lldb/Utility/LLDBLog.h" #include "lldb/Utility/Log.h" #include "lldb/Utility/Timer.h" #include #include using namespace lldb; using namespace lldb_private; using namespace lldb_private::dwarf; // GetDwarfEHPtr // // Used for calls when the value type is specified by a DWARF EH Frame pointer // encoding. static uint64_t GetGNUEHPointer(const DataExtractor &DE, offset_t *offset_ptr, uint32_t eh_ptr_enc, addr_t pc_rel_addr, addr_t text_addr, addr_t data_addr) //, BSDRelocs *data_relocs) const { if (eh_ptr_enc == DW_EH_PE_omit) return ULLONG_MAX; // Value isn't in the buffer... uint64_t baseAddress = 0; uint64_t addressValue = 0; const uint32_t addr_size = DE.GetAddressByteSize(); assert(addr_size == 4 || addr_size == 8); bool signExtendValue = false; // Decode the base part or adjust our offset switch (eh_ptr_enc & 0x70) { case DW_EH_PE_pcrel: signExtendValue = true; baseAddress = *offset_ptr; if (pc_rel_addr != LLDB_INVALID_ADDRESS) baseAddress += pc_rel_addr; // else // Log::GlobalWarning ("PC relative pointer encoding found with // invalid pc relative address."); break; case DW_EH_PE_textrel: signExtendValue = true; if (text_addr != LLDB_INVALID_ADDRESS) baseAddress = text_addr; // else // Log::GlobalWarning ("text relative pointer encoding being // decoded with invalid text section address, setting base address // to zero."); break; case DW_EH_PE_datarel: signExtendValue = true; if (data_addr != LLDB_INVALID_ADDRESS) baseAddress = data_addr; // else // Log::GlobalWarning ("data relative pointer encoding being // decoded with invalid data section address, setting base address // to zero."); break; case DW_EH_PE_funcrel: signExtendValue = true; break; case DW_EH_PE_aligned: { // SetPointerSize should be called prior to extracting these so the pointer // size is cached assert(addr_size != 0); if (addr_size) { // Align to a address size boundary first uint32_t alignOffset = *offset_ptr % addr_size; if (alignOffset) offset_ptr += addr_size - alignOffset; } } break; default: break; } // Decode the value part switch (eh_ptr_enc & DW_EH_PE_MASK_ENCODING) { case DW_EH_PE_absptr: { addressValue = DE.GetAddress(offset_ptr); // if (data_relocs) // addressValue = data_relocs->Relocate(*offset_ptr - // addr_size, *this, addressValue); } break; case DW_EH_PE_uleb128: addressValue = DE.GetULEB128(offset_ptr); break; case DW_EH_PE_udata2: addressValue = DE.GetU16(offset_ptr); break; case DW_EH_PE_udata4: addressValue = DE.GetU32(offset_ptr); break; case DW_EH_PE_udata8: addressValue = DE.GetU64(offset_ptr); break; case DW_EH_PE_sleb128: addressValue = DE.GetSLEB128(offset_ptr); break; case DW_EH_PE_sdata2: addressValue = (int16_t)DE.GetU16(offset_ptr); break; case DW_EH_PE_sdata4: addressValue = (int32_t)DE.GetU32(offset_ptr); break; case DW_EH_PE_sdata8: addressValue = (int64_t)DE.GetU64(offset_ptr); break; default: // Unhandled encoding type assert(eh_ptr_enc); break; } // Since we promote everything to 64 bit, we may need to sign extend if (signExtendValue && addr_size < sizeof(baseAddress)) { uint64_t sign_bit = 1ull << ((addr_size * 8ull) - 1ull); if (sign_bit & addressValue) { uint64_t mask = ~sign_bit + 1; addressValue |= mask; } } return baseAddress + addressValue; } DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile &objfile, SectionSP §ion_sp, Type type) : m_objfile(objfile), m_section_sp(section_sp), m_type(type) {} bool DWARFCallFrameInfo::GetUnwindPlan(const Address &addr, UnwindPlan &unwind_plan) { return GetUnwindPlan(AddressRange(addr, 1), unwind_plan); } bool DWARFCallFrameInfo::GetUnwindPlan(const AddressRange &range, UnwindPlan &unwind_plan) { FDEEntryMap::Entry fde_entry; Address addr = range.GetBaseAddress(); // 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() == nullptr || module_sp->GetObjectFile() == nullptr || module_sp->GetObjectFile() != &m_objfile) return false; if (llvm::Optional entry = GetFirstFDEEntryInRange(range)) return FDEToUnwindPlan(entry->data, addr, unwind_plan); return false; } 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() == nullptr || module_sp->GetObjectFile() == nullptr || module_sp->GetObjectFile() != &m_objfile) return false; if (m_section_sp.get() == nullptr || 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; } llvm::Optional DWARFCallFrameInfo::GetFirstFDEEntryInRange(const AddressRange &range) { if (!m_section_sp || m_section_sp->IsEncrypted()) return llvm::None; GetFDEIndex(); addr_t start_file_addr = range.GetBaseAddress().GetFileAddress(); const FDEEntryMap::Entry *fde = m_fde_index.FindEntryThatContainsOrFollows(start_file_addr); if (fde && fde->DoesIntersect( FDEEntryMap::Range(start_file_addr, range.GetByteSize()))) return *fde; return llvm::None; } 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 == nullptr) pos->second = ParseCIE(cie_offset); return pos->second.get(); } return nullptr; } 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) GetCFIData(); uint32_t length = m_cfi_data.GetU32(&offset); dw_offset_t cie_id, end_offset; bool is_64bit = (length == UINT32_MAX); if (is_64bit) { length = m_cfi_data.GetU64(&offset); cie_id = m_cfi_data.GetU64(&offset); end_offset = cie_offset + length + 12; } else { cie_id = m_cfi_data.GetU32(&offset); end_offset = cie_offset + length + 4; } if (length > 0 && ((m_type == DWARF && cie_id == UINT32_MAX) || (m_type == EH && 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); if (cie_sp->version > CFI_VERSION4) { Host::SystemLog(Host::eSystemLogError, "CIE parse error: CFI version %d is not supported\n", cie_sp->version); return nullptr; } for (i = 0; i < CFI_AUG_MAX_SIZE; ++i) { cie_sp->augmentation[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; j < CFI_AUG_MAX_SIZE; ++j) cie_sp->augmentation[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 nullptr; } // m_cfi_data uses address size from target architecture of the process may // ignore these fields? if (m_type == DWARF && cie_sp->version >= CFI_VERSION4) { cie_sp->address_size = m_cfi_data.GetU8(&offset); cie_sp->segment_size = m_cfi_data.GetU8(&offset); } 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_type == DWARF && cie_sp->version >= CFI_VERSION3 ? static_cast(m_cfi_data.GetULEB128(&offset)) : 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 interpreted 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. cie_sp->lsda_addr_encoding = m_cfi_data.GetU8(&offset); break; case 'P': // Indicates the presence of two arguments in the Augmentation Data // of the CIE. 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. // // The address of the personality function will be stored at this // location. Pre-execution, it will be all zero's so don't read it // until we're trying to do an unwind & the reloc has been // resolved. { uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); cie_sp->personality_loc = GetGNUEHPointer( m_cfi_data, &offset, arg_ptr_encoding, pc_rel_addr, 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 (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, cie_sp->data_align, offset, cie_sp->initial_row)) break; // Stop if we hit an unrecognized opcode } } return cie_sp; } void DWARFCallFrameInfo::GetCFIData() { if (!m_cfi_data_initialized) { Log *log = GetLog(LLDBLog::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() == nullptr || m_section_sp->IsEncrypted()) return; if (m_fde_index_initialized) return; std::lock_guard guard(m_fde_index_mutex); if (m_fde_index_initialized) // if two threads hit the locker return; LLDB_SCOPED_TIMERF("%s - %s", LLVM_PRETTY_FUNCTION, m_objfile.GetFileSpec().GetFilename().AsCString("")); bool clear_address_zeroth_bit = false; if (ArchSpec arch = m_objfile.GetArchitecture()) { if (arch.GetTriple().getArch() == llvm::Triple::arm || arch.GetTriple().getArch() == llvm::Triple::thumb) clear_address_zeroth_bit = true; } lldb::offset_t offset = 0; if (!m_cfi_data_initialized) GetCFIData(); while (m_cfi_data.ValidOffsetForDataOfSize(offset, 8)) { const dw_offset_t current_entry = offset; dw_offset_t cie_id, next_entry, cie_offset; uint32_t len = m_cfi_data.GetU32(&offset); bool is_64bit = (len == UINT32_MAX); if (is_64bit) { len = m_cfi_data.GetU64(&offset); cie_id = m_cfi_data.GetU64(&offset); next_entry = current_entry + len + 12; cie_offset = current_entry + 12 - cie_id; } else { cie_id = m_cfi_data.GetU32(&offset); next_entry = current_entry + len + 4; cie_offset = current_entry + 4 - cie_id; } if (next_entry > m_cfi_data.GetByteSize() + 1) { Host::SystemLog(Host::eSystemLogError, "error: Invalid fde/cie next " "entry offset of 0x%x found in " "cie/fde at 0x%x\n", next_entry, current_entry); // Don't trust anything in this eh_frame section if we find blatantly // invalid data. m_fde_index.Clear(); m_fde_index_initialized = true; return; } // An FDE entry contains CIE_pointer in debug_frame in same place as cie_id // in eh_frame. CIE_pointer is an offset into the .debug_frame section. So, // variable cie_offset should be equal to cie_id for debug_frame. // FDE entries with cie_id == 0 shouldn't be ignored for it. if ((cie_id == 0 && m_type == EH) || cie_id == UINT32_MAX || len == 0) { auto cie_sp = ParseCIE(current_entry); if (!cie_sp) { // Cannot parse, the reason is already logged m_fde_index.Clear(); m_fde_index_initialized = true; return; } m_cie_map[current_entry] = std::move(cie_sp); offset = next_entry; continue; } if (m_type == DWARF) cie_offset = cie_id; if (cie_offset > m_cfi_data.GetByteSize()) { Host::SystemLog(Host::eSystemLogError, "error: Invalid cie offset of 0x%x " "found in cie/fde at 0x%x\n", cie_offset, current_entry); // Don't trust anything in this eh_frame section if we find blatantly // invalid data. m_fde_index.Clear(); m_fde_index_initialized = true; return; } 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 = GetGNUEHPointer(m_cfi_data, &offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); if (clear_address_zeroth_bit) addr &= ~1ull; lldb::addr_t length = GetGNUEHPointer( m_cfi_data, &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) { Log *log = GetLog(LLDBLog::Unwind); lldb::offset_t offset = dwarf_offset; lldb::offset_t current_entry = offset; if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) return false; if (!m_cfi_data_initialized) GetCFIData(); uint32_t length = m_cfi_data.GetU32(&offset); dw_offset_t cie_offset; bool is_64bit = (length == UINT32_MAX); if (is_64bit) { length = m_cfi_data.GetU64(&offset); cie_offset = m_cfi_data.GetU64(&offset); } else { cie_offset = m_cfi_data.GetU32(&offset); } // FDE entries with zeroth cie_offset may occur for debug_frame. assert(!(m_type == EH && 0 == cie_offset) && 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_type == EH) { unwind_plan.SetSourceName("eh_frame CFI"); cie_offset = current_entry + (is_64bit ? 12 : 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 != nullptr); const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 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 = GetGNUEHPointer(m_cfi_data, &offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); lldb::addr_t range_len = GetGNUEHPointer( m_cfi_data, &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); addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; if (cie->augmentation[0] == 'z') { uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) { offset_t saved_offset = offset; lsda_data_file_address = GetGNUEHPointer(m_cfi_data, &offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); if (offset - saved_offset != aug_data_len) { // There is more in the augmentation region than we know how to process; // don't read anything. lsda_data_file_address = LLDB_INVALID_ADDRESS; } offset = saved_offset; } offset += aug_data_len; } unwind_plan.SetUnwindPlanForSignalTrap( strchr(cie->augmentation, 'S') ? eLazyBoolYes : eLazyBoolNo); Address lsda_data; Address personality_function_ptr; if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS) { m_objfile.GetModule()->ResolveFileAddress(lsda_data_file_address, lsda_data); m_objfile.GetModule()->ResolveFileAddress(cie->personality_loc, personality_function_ptr); } if (lsda_data.IsValid() && personality_function_ptr.IsValid()) { unwind_plan.SetLSDAAddress(lsda_data); unwind_plan.SetPersonalityFunctionPtr(personality_function_ptr); } 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(GetRegisterKind()); 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 (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, offset, *row)) { 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_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. uint32_t 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 eh_frame 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_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.GetAddress(&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_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. uint32_t 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_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.) if (stack.empty()) { LLDB_LOGF(log, "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32 ", startaddr: %" PRIx64 " encountered DW_CFA_restore_state but state stack " "is empty. Corrupt unwind info?", __FUNCTION__, dwarf_offset, startaddr.GetFileAddress()); break; } lldb::addr_t offset = row->GetOffset(); row = stack.back(); stack.pop_back(); row->SetOffset(offset); break; } case DW_CFA_GNU_args_size: // 0x2e { // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 // operand representing an argument size. This instruction specifies // the total of the size of the arguments which have been pushed onto // the stack. // TODO: Figure out how we should handle this. m_cfi_data.GetULEB128(&offset); break; } case DW_CFA_val_offset: // 0x14 case DW_CFA_val_offset_sf: // 0x15 default: break; } } } } unwind_plan.AppendRow(row); return true; } bool DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode, uint8_t extended_opcode, int32_t data_align, lldb::offset_t &offset, UnwindPlan::Row &row) { UnwindPlan::Row::RegisterLocation reg_location; if (primary_opcode) { switch (primary_opcode) { 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). uint8_t reg_num = extended_opcode; int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; reg_location.SetAtCFAPlusOffset(op_offset); row.SetRegisterInfo(reg_num, reg_location); return true; } } } else { switch (extended_opcode) { case DW_CFA_nop: // 0x0 return true; 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetAtCFAPlusOffset(op_offset); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetUndefined(); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetSame(); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetInRegister(other_reg_num); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); return true; } 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). uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, row.GetCFAValue().GetOffset()); return true; } 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). int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); row.GetCFAValue().SetIsRegisterPlusOffset( row.GetCFAValue().GetRegisterNumber(), op_offset); return true; } case DW_CFA_def_cfa_expression: // 0xF (CFA Definition Instruction) { size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); const uint8_t *block_data = static_cast(m_cfi_data.GetData(&offset, block_len)); row.GetCFAValue().SetIsDWARFExpression(block_data, block_len); return true; } 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. uint32_t 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 = static_cast(m_cfi_data.GetData(&offset, block_len)); UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetAtDWARFExpression(block_data, block_len); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; UnwindPlan::Row::RegisterLocation reg_location; reg_location.SetAtCFAPlusOffset(op_offset); row.SetRegisterInfo(reg_num, reg_location); return true; } 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. uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); return true; } 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. int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber(); row.GetCFAValue().SetIsRegisterPlusOffset(cfa_regnum, op_offset); return true; } 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. uint32_t 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 = (const uint8_t *)m_cfi_data.GetData(&offset, block_len); reg_location.SetIsDWARFExpression(block_data, block_len); row.SetRegisterInfo(reg_num, reg_location); return true; } } } return false; } void DWARFCallFrameInfo::ForEachFDEEntries( const std::function &callback) { GetFDEIndex(); for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) { const FDEEntryMap::Entry &entry = m_fde_index.GetEntryRef(i); if (!callback(entry.base, entry.size, entry.data)) break; } }