| //===-- DWARFDebugLine.cpp ------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "DWARFDebugLine.h" |
| #include "llvm/Support/Dwarf.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <algorithm> |
| using namespace llvm; |
| using namespace dwarf; |
| |
| void DWARFDebugLine::Prologue::dump(raw_ostream &OS) const { |
| OS << "Line table prologue:\n" |
| << format(" total_length: 0x%8.8x\n", TotalLength) |
| << format(" version: %u\n", Version) |
| << format("prologue_length: 0x%8.8x\n", PrologueLength) |
| << format("min_inst_length: %u\n", MinInstLength) |
| << format("default_is_stmt: %u\n", DefaultIsStmt) |
| << format(" line_base: %i\n", LineBase) |
| << format(" line_range: %u\n", LineRange) |
| << format(" opcode_base: %u\n", OpcodeBase); |
| |
| for (uint32_t i = 0; i < StandardOpcodeLengths.size(); ++i) |
| OS << format("standard_opcode_lengths[%s] = %u\n", LNStandardString(i+1), |
| StandardOpcodeLengths[i]); |
| |
| if (!IncludeDirectories.empty()) |
| for (uint32_t i = 0; i < IncludeDirectories.size(); ++i) |
| OS << format("include_directories[%3u] = '", i+1) |
| << IncludeDirectories[i] << "'\n"; |
| |
| if (!FileNames.empty()) { |
| OS << " Dir Mod Time File Len File Name\n" |
| << " ---- ---------- ---------- -----------" |
| "----------------\n"; |
| for (uint32_t i = 0; i < FileNames.size(); ++i) { |
| const FileNameEntry& fileEntry = FileNames[i]; |
| OS << format("file_names[%3u] %4" PRIu64 " ", i+1, fileEntry.DirIdx) |
| << format("0x%8.8" PRIx64 " 0x%8.8" PRIx64 " ", |
| fileEntry.ModTime, fileEntry.Length) |
| << fileEntry.Name << '\n'; |
| } |
| } |
| } |
| |
| void DWARFDebugLine::Row::postAppend() { |
| BasicBlock = false; |
| PrologueEnd = false; |
| EpilogueBegin = false; |
| } |
| |
| void DWARFDebugLine::Row::reset(bool default_is_stmt) { |
| Address = 0; |
| Line = 1; |
| Column = 0; |
| File = 1; |
| Isa = 0; |
| IsStmt = default_is_stmt; |
| BasicBlock = false; |
| EndSequence = false; |
| PrologueEnd = false; |
| EpilogueBegin = false; |
| } |
| |
| void DWARFDebugLine::Row::dump(raw_ostream &OS) const { |
| OS << format("0x%16.16" PRIx64 " %6u %6u", Address, Line, Column) |
| << format(" %6u %3u ", File, Isa) |
| << (IsStmt ? " is_stmt" : "") |
| << (BasicBlock ? " basic_block" : "") |
| << (PrologueEnd ? " prologue_end" : "") |
| << (EpilogueBegin ? " epilogue_begin" : "") |
| << (EndSequence ? " end_sequence" : "") |
| << '\n'; |
| } |
| |
| void DWARFDebugLine::LineTable::dump(raw_ostream &OS) const { |
| Prologue.dump(OS); |
| OS << '\n'; |
| |
| if (!Rows.empty()) { |
| OS << "Address Line Column File ISA Flags\n" |
| << "------------------ ------ ------ ------ --- -------------\n"; |
| for (std::vector<Row>::const_iterator pos = Rows.begin(), |
| end = Rows.end(); pos != end; ++pos) |
| pos->dump(OS); |
| } |
| } |
| |
| DWARFDebugLine::State::~State() {} |
| |
| void DWARFDebugLine::State::appendRowToMatrix(uint32_t offset) { |
| if (Sequence::Empty) { |
| // Record the beginning of instruction sequence. |
| Sequence::Empty = false; |
| Sequence::LowPC = Address; |
| Sequence::FirstRowIndex = row; |
| } |
| ++row; // Increase the row number. |
| LineTable::appendRow(*this); |
| if (EndSequence) { |
| // Record the end of instruction sequence. |
| Sequence::HighPC = Address; |
| Sequence::LastRowIndex = row; |
| if (Sequence::isValid()) |
| LineTable::appendSequence(*this); |
| Sequence::reset(); |
| } |
| Row::postAppend(); |
| } |
| |
| void DWARFDebugLine::State::finalize() { |
| row = DoneParsingLineTable; |
| if (!Sequence::Empty) { |
| fprintf(stderr, "warning: last sequence in debug line table is not" |
| "terminated!\n"); |
| } |
| // Sort all sequences so that address lookup will work faster. |
| if (!Sequences.empty()) { |
| std::sort(Sequences.begin(), Sequences.end(), Sequence::orderByLowPC); |
| // Note: actually, instruction address ranges of sequences should not |
| // overlap (in shared objects and executables). If they do, the address |
| // lookup would still work, though, but result would be ambiguous. |
| // We don't report warning in this case. For example, |
| // sometimes .so compiled from multiple object files contains a few |
| // rudimentary sequences for address ranges [0x0, 0xsomething). |
| } |
| } |
| |
| DWARFDebugLine::DumpingState::~DumpingState() {} |
| |
| void DWARFDebugLine::DumpingState::finalize() { |
| LineTable::dump(OS); |
| } |
| |
| const DWARFDebugLine::LineTable * |
| DWARFDebugLine::getLineTable(uint32_t offset) const { |
| LineTableConstIter pos = LineTableMap.find(offset); |
| if (pos != LineTableMap.end()) |
| return &pos->second; |
| return 0; |
| } |
| |
| const DWARFDebugLine::LineTable * |
| DWARFDebugLine::getOrParseLineTable(DataExtractor debug_line_data, |
| uint32_t offset) { |
| std::pair<LineTableIter, bool> pos = |
| LineTableMap.insert(LineTableMapTy::value_type(offset, LineTable())); |
| if (pos.second) { |
| // Parse and cache the line table for at this offset. |
| State state; |
| if (!parseStatementTable(debug_line_data, RelocMap, &offset, state)) |
| return 0; |
| pos.first->second = state; |
| } |
| return &pos.first->second; |
| } |
| |
| bool |
| DWARFDebugLine::parsePrologue(DataExtractor debug_line_data, |
| uint32_t *offset_ptr, Prologue *prologue) { |
| const uint32_t prologue_offset = *offset_ptr; |
| |
| prologue->clear(); |
| prologue->TotalLength = debug_line_data.getU32(offset_ptr); |
| prologue->Version = debug_line_data.getU16(offset_ptr); |
| if (prologue->Version != 2) |
| return false; |
| |
| prologue->PrologueLength = debug_line_data.getU32(offset_ptr); |
| const uint32_t end_prologue_offset = prologue->PrologueLength + *offset_ptr; |
| prologue->MinInstLength = debug_line_data.getU8(offset_ptr); |
| prologue->DefaultIsStmt = debug_line_data.getU8(offset_ptr); |
| prologue->LineBase = debug_line_data.getU8(offset_ptr); |
| prologue->LineRange = debug_line_data.getU8(offset_ptr); |
| prologue->OpcodeBase = debug_line_data.getU8(offset_ptr); |
| |
| prologue->StandardOpcodeLengths.reserve(prologue->OpcodeBase-1); |
| for (uint32_t i = 1; i < prologue->OpcodeBase; ++i) { |
| uint8_t op_len = debug_line_data.getU8(offset_ptr); |
| prologue->StandardOpcodeLengths.push_back(op_len); |
| } |
| |
| while (*offset_ptr < end_prologue_offset) { |
| const char *s = debug_line_data.getCStr(offset_ptr); |
| if (s && s[0]) |
| prologue->IncludeDirectories.push_back(s); |
| else |
| break; |
| } |
| |
| while (*offset_ptr < end_prologue_offset) { |
| const char *name = debug_line_data.getCStr(offset_ptr); |
| if (name && name[0]) { |
| FileNameEntry fileEntry; |
| fileEntry.Name = name; |
| fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr); |
| fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr); |
| fileEntry.Length = debug_line_data.getULEB128(offset_ptr); |
| prologue->FileNames.push_back(fileEntry); |
| } else { |
| break; |
| } |
| } |
| |
| if (*offset_ptr != end_prologue_offset) { |
| fprintf(stderr, "warning: parsing line table prologue at 0x%8.8x should" |
| " have ended at 0x%8.8x but it ended ad 0x%8.8x\n", |
| prologue_offset, end_prologue_offset, *offset_ptr); |
| return false; |
| } |
| return true; |
| } |
| |
| bool |
| DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data, |
| const RelocAddrMap *RMap, |
| uint32_t *offset_ptr, State &state) { |
| const uint32_t debug_line_offset = *offset_ptr; |
| |
| Prologue *prologue = &state.Prologue; |
| |
| if (!parsePrologue(debug_line_data, offset_ptr, prologue)) { |
| // Restore our offset and return false to indicate failure! |
| *offset_ptr = debug_line_offset; |
| return false; |
| } |
| |
| const uint32_t end_offset = debug_line_offset + prologue->TotalLength + |
| sizeof(prologue->TotalLength); |
| |
| state.reset(); |
| |
| while (*offset_ptr < end_offset) { |
| uint8_t opcode = debug_line_data.getU8(offset_ptr); |
| |
| if (opcode == 0) { |
| // Extended Opcodes always start with a zero opcode followed by |
| // a uleb128 length so you can skip ones you don't know about |
| uint32_t ext_offset = *offset_ptr; |
| uint64_t len = debug_line_data.getULEB128(offset_ptr); |
| uint32_t arg_size = len - (*offset_ptr - ext_offset); |
| |
| uint8_t sub_opcode = debug_line_data.getU8(offset_ptr); |
| switch (sub_opcode) { |
| case DW_LNE_end_sequence: |
| // Set the end_sequence register of the state machine to true and |
| // append a row to the matrix using the current values of the |
| // state-machine registers. Then reset the registers to the initial |
| // values specified above. Every statement program sequence must end |
| // with a DW_LNE_end_sequence instruction which creates a row whose |
| // address is that of the byte after the last target machine instruction |
| // of the sequence. |
| state.EndSequence = true; |
| state.appendRowToMatrix(*offset_ptr); |
| state.reset(); |
| break; |
| |
| case DW_LNE_set_address: |
| // Takes a single relocatable address as an operand. The size of the |
| // operand is the size appropriate to hold an address on the target |
| // machine. Set the address register to the value given by the |
| // relocatable address. All of the other statement program opcodes |
| // that affect the address register add a delta to it. This instruction |
| // stores a relocatable value into it instead. |
| { |
| // If this address is in our relocation map, apply the relocation. |
| RelocAddrMap::const_iterator AI = RMap->find(*offset_ptr); |
| if (AI != RMap->end()) { |
| const std::pair<uint8_t, int64_t> &R = AI->second; |
| state.Address = debug_line_data.getAddress(offset_ptr) + R.second; |
| } else |
| state.Address = debug_line_data.getAddress(offset_ptr); |
| } |
| break; |
| |
| case DW_LNE_define_file: |
| // Takes 4 arguments. The first is a null terminated string containing |
| // a source file name. The second is an unsigned LEB128 number |
| // representing the directory index of the directory in which the file |
| // was found. The third is an unsigned LEB128 number representing the |
| // time of last modification of the file. The fourth is an unsigned |
| // LEB128 number representing the length in bytes of the file. The time |
| // and length fields may contain LEB128(0) if the information is not |
| // available. |
| // |
| // The directory index represents an entry in the include_directories |
| // section of the statement program prologue. The index is LEB128(0) |
| // if the file was found in the current directory of the compilation, |
| // LEB128(1) if it was found in the first directory in the |
| // include_directories section, and so on. The directory index is |
| // ignored for file names that represent full path names. |
| // |
| // The files are numbered, starting at 1, in the order in which they |
| // appear; the names in the prologue come before names defined by |
| // the DW_LNE_define_file instruction. These numbers are used in the |
| // the file register of the state machine. |
| { |
| FileNameEntry fileEntry; |
| fileEntry.Name = debug_line_data.getCStr(offset_ptr); |
| fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr); |
| fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr); |
| fileEntry.Length = debug_line_data.getULEB128(offset_ptr); |
| prologue->FileNames.push_back(fileEntry); |
| } |
| break; |
| |
| default: |
| // Length doesn't include the zero opcode byte or the length itself, but |
| // it does include the sub_opcode, so we have to adjust for that below |
| (*offset_ptr) += arg_size; |
| break; |
| } |
| } else if (opcode < prologue->OpcodeBase) { |
| switch (opcode) { |
| // Standard Opcodes |
| case DW_LNS_copy: |
| // Takes no arguments. Append a row to the matrix using the |
| // current values of the state-machine registers. Then set |
| // the basic_block register to false. |
| state.appendRowToMatrix(*offset_ptr); |
| break; |
| |
| case DW_LNS_advance_pc: |
| // Takes a single unsigned LEB128 operand, multiplies it by the |
| // min_inst_length field of the prologue, and adds the |
| // result to the address register of the state machine. |
| state.Address += debug_line_data.getULEB128(offset_ptr) * |
| prologue->MinInstLength; |
| break; |
| |
| case DW_LNS_advance_line: |
| // Takes a single signed LEB128 operand and adds that value to |
| // the line register of the state machine. |
| state.Line += debug_line_data.getSLEB128(offset_ptr); |
| break; |
| |
| case DW_LNS_set_file: |
| // Takes a single unsigned LEB128 operand and stores it in the file |
| // register of the state machine. |
| state.File = debug_line_data.getULEB128(offset_ptr); |
| break; |
| |
| case DW_LNS_set_column: |
| // Takes a single unsigned LEB128 operand and stores it in the |
| // column register of the state machine. |
| state.Column = debug_line_data.getULEB128(offset_ptr); |
| break; |
| |
| case DW_LNS_negate_stmt: |
| // Takes no arguments. Set the is_stmt register of the state |
| // machine to the logical negation of its current value. |
| state.IsStmt = !state.IsStmt; |
| break; |
| |
| case DW_LNS_set_basic_block: |
| // Takes no arguments. Set the basic_block register of the |
| // state machine to true |
| state.BasicBlock = true; |
| break; |
| |
| case DW_LNS_const_add_pc: |
| // Takes no arguments. Add to the address register of the state |
| // machine the address increment value corresponding to special |
| // opcode 255. The motivation for DW_LNS_const_add_pc is this: |
| // when the statement program needs to advance the address by a |
| // small amount, it can use a single special opcode, which occupies |
| // a single byte. When it needs to advance the address by up to |
| // twice the range of the last special opcode, it can use |
| // DW_LNS_const_add_pc followed by a special opcode, for a total |
| // of two bytes. Only if it needs to advance the address by more |
| // than twice that range will it need to use both DW_LNS_advance_pc |
| // and a special opcode, requiring three or more bytes. |
| { |
| uint8_t adjust_opcode = 255 - prologue->OpcodeBase; |
| uint64_t addr_offset = (adjust_opcode / prologue->LineRange) * |
| prologue->MinInstLength; |
| state.Address += addr_offset; |
| } |
| break; |
| |
| case DW_LNS_fixed_advance_pc: |
| // Takes a single uhalf operand. Add to the address register of |
| // the state machine the value of the (unencoded) operand. This |
| // is the only extended opcode that takes an argument that is not |
| // a variable length number. The motivation for DW_LNS_fixed_advance_pc |
| // is this: existing assemblers cannot emit DW_LNS_advance_pc or |
| // special opcodes because they cannot encode LEB128 numbers or |
| // judge when the computation of a special opcode overflows and |
| // requires the use of DW_LNS_advance_pc. Such assemblers, however, |
| // can use DW_LNS_fixed_advance_pc instead, sacrificing compression. |
| state.Address += debug_line_data.getU16(offset_ptr); |
| break; |
| |
| case DW_LNS_set_prologue_end: |
| // Takes no arguments. Set the prologue_end register of the |
| // state machine to true |
| state.PrologueEnd = true; |
| break; |
| |
| case DW_LNS_set_epilogue_begin: |
| // Takes no arguments. Set the basic_block register of the |
| // state machine to true |
| state.EpilogueBegin = true; |
| break; |
| |
| case DW_LNS_set_isa: |
| // Takes a single unsigned LEB128 operand and stores it in the |
| // column register of the state machine. |
| state.Isa = debug_line_data.getULEB128(offset_ptr); |
| break; |
| |
| default: |
| // Handle any unknown standard opcodes here. We know the lengths |
| // of such opcodes because they are specified in the prologue |
| // as a multiple of LEB128 operands for each opcode. |
| { |
| assert(opcode - 1U < prologue->StandardOpcodeLengths.size()); |
| uint8_t opcode_length = prologue->StandardOpcodeLengths[opcode - 1]; |
| for (uint8_t i=0; i<opcode_length; ++i) |
| debug_line_data.getULEB128(offset_ptr); |
| } |
| break; |
| } |
| } else { |
| // Special Opcodes |
| |
| // A special opcode value is chosen based on the amount that needs |
| // to be added to the line and address registers. The maximum line |
| // increment for a special opcode is the value of the line_base |
| // field in the header, plus the value of the line_range field, |
| // minus 1 (line base + line range - 1). If the desired line |
| // increment is greater than the maximum line increment, a standard |
| // opcode must be used instead of a special opcode. The "address |
| // advance" is calculated by dividing the desired address increment |
| // by the minimum_instruction_length field from the header. The |
| // special opcode is then calculated using the following formula: |
| // |
| // opcode = (desired line increment - line_base) + |
| // (line_range * address advance) + opcode_base |
| // |
| // If the resulting opcode is greater than 255, a standard opcode |
| // must be used instead. |
| // |
| // To decode a special opcode, subtract the opcode_base from the |
| // opcode itself to give the adjusted opcode. The amount to |
| // increment the address register is the result of the adjusted |
| // opcode divided by the line_range multiplied by the |
| // minimum_instruction_length field from the header. That is: |
| // |
| // address increment = (adjusted opcode / line_range) * |
| // minimum_instruction_length |
| // |
| // The amount to increment the line register is the line_base plus |
| // the result of the adjusted opcode modulo the line_range. That is: |
| // |
| // line increment = line_base + (adjusted opcode % line_range) |
| |
| uint8_t adjust_opcode = opcode - prologue->OpcodeBase; |
| uint64_t addr_offset = (adjust_opcode / prologue->LineRange) * |
| prologue->MinInstLength; |
| int32_t line_offset = prologue->LineBase + |
| (adjust_opcode % prologue->LineRange); |
| state.Line += line_offset; |
| state.Address += addr_offset; |
| state.appendRowToMatrix(*offset_ptr); |
| } |
| } |
| |
| state.finalize(); |
| |
| return end_offset; |
| } |
| |
| uint32_t |
| DWARFDebugLine::LineTable::lookupAddress(uint64_t address) const { |
| uint32_t unknown_index = UINT32_MAX; |
| if (Sequences.empty()) |
| return unknown_index; |
| // First, find an instruction sequence containing the given address. |
| DWARFDebugLine::Sequence sequence; |
| sequence.LowPC = address; |
| SequenceIter first_seq = Sequences.begin(); |
| SequenceIter last_seq = Sequences.end(); |
| SequenceIter seq_pos = std::lower_bound(first_seq, last_seq, sequence, |
| DWARFDebugLine::Sequence::orderByLowPC); |
| DWARFDebugLine::Sequence found_seq; |
| if (seq_pos == last_seq) { |
| found_seq = Sequences.back(); |
| } else if (seq_pos->LowPC == address) { |
| found_seq = *seq_pos; |
| } else { |
| if (seq_pos == first_seq) |
| return unknown_index; |
| found_seq = *(seq_pos - 1); |
| } |
| if (!found_seq.containsPC(address)) |
| return unknown_index; |
| // Search for instruction address in the rows describing the sequence. |
| // Rows are stored in a vector, so we may use arithmetical operations with |
| // iterators. |
| DWARFDebugLine::Row row; |
| row.Address = address; |
| RowIter first_row = Rows.begin() + found_seq.FirstRowIndex; |
| RowIter last_row = Rows.begin() + found_seq.LastRowIndex; |
| RowIter row_pos = std::lower_bound(first_row, last_row, row, |
| DWARFDebugLine::Row::orderByAddress); |
| if (row_pos == last_row) { |
| return found_seq.LastRowIndex - 1; |
| } |
| uint32_t index = found_seq.FirstRowIndex + (row_pos - first_row); |
| if (row_pos->Address > address) { |
| if (row_pos == first_row) |
| return unknown_index; |
| else |
| index--; |
| } |
| return index; |
| } |
| |
| bool |
| DWARFDebugLine::LineTable::lookupAddressRange(uint64_t address, |
| uint64_t size, |
| std::vector<uint32_t>& result) const { |
| if (Sequences.empty()) |
| return false; |
| uint64_t end_addr = address + size; |
| // First, find an instruction sequence containing the given address. |
| DWARFDebugLine::Sequence sequence; |
| sequence.LowPC = address; |
| SequenceIter first_seq = Sequences.begin(); |
| SequenceIter last_seq = Sequences.end(); |
| SequenceIter seq_pos = std::lower_bound(first_seq, last_seq, sequence, |
| DWARFDebugLine::Sequence::orderByLowPC); |
| if (seq_pos == last_seq || seq_pos->LowPC != address) { |
| if (seq_pos == first_seq) |
| return false; |
| seq_pos--; |
| } |
| if (!seq_pos->containsPC(address)) |
| return false; |
| |
| SequenceIter start_pos = seq_pos; |
| |
| // Add the rows from the first sequence to the vector, starting with the |
| // index we just calculated |
| |
| while (seq_pos != last_seq && seq_pos->LowPC < end_addr) { |
| DWARFDebugLine::Sequence cur_seq = *seq_pos; |
| uint32_t first_row_index; |
| uint32_t last_row_index; |
| if (seq_pos == start_pos) { |
| // For the first sequence, we need to find which row in the sequence is the |
| // first in our range. Rows are stored in a vector, so we may use |
| // arithmetical operations with iterators. |
| DWARFDebugLine::Row row; |
| row.Address = address; |
| RowIter first_row = Rows.begin() + cur_seq.FirstRowIndex; |
| RowIter last_row = Rows.begin() + cur_seq.LastRowIndex; |
| RowIter row_pos = std::upper_bound(first_row, last_row, row, |
| DWARFDebugLine::Row::orderByAddress); |
| // The 'row_pos' iterator references the first row that is greater than |
| // our start address. Unless that's the first row, we want to start at |
| // the row before that. |
| first_row_index = cur_seq.FirstRowIndex + (row_pos - first_row); |
| if (row_pos != first_row) |
| --first_row_index; |
| } else |
| first_row_index = cur_seq.FirstRowIndex; |
| |
| // For the last sequence in our range, we need to figure out the last row in |
| // range. For all other sequences we can go to the end of the sequence. |
| if (cur_seq.HighPC > end_addr) { |
| DWARFDebugLine::Row row; |
| row.Address = end_addr; |
| RowIter first_row = Rows.begin() + cur_seq.FirstRowIndex; |
| RowIter last_row = Rows.begin() + cur_seq.LastRowIndex; |
| RowIter row_pos = std::upper_bound(first_row, last_row, row, |
| DWARFDebugLine::Row::orderByAddress); |
| // The 'row_pos' iterator references the first row that is greater than |
| // our end address. The row before that is the last row we want. |
| last_row_index = cur_seq.FirstRowIndex + (row_pos - first_row) - 1; |
| } else |
| // Contrary to what you might expect, DWARFDebugLine::SequenceLastRowIndex |
| // isn't a valid index within the current sequence. It's that plus one. |
| last_row_index = cur_seq.LastRowIndex - 1; |
| |
| for (uint32_t i = first_row_index; i <= last_row_index; ++i) { |
| result.push_back(i); |
| } |
| |
| ++seq_pos; |
| } |
| |
| return true; |
| } |
| |
| bool |
| DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex, |
| bool NeedsAbsoluteFilePath, |
| std::string &Result) const { |
| if (FileIndex == 0 || FileIndex > Prologue.FileNames.size()) |
| return false; |
| const FileNameEntry &Entry = Prologue.FileNames[FileIndex - 1]; |
| const char *FileName = Entry.Name; |
| if (!NeedsAbsoluteFilePath || |
| sys::path::is_absolute(FileName)) { |
| Result = FileName; |
| return true; |
| } |
| SmallString<16> FilePath; |
| uint64_t IncludeDirIndex = Entry.DirIdx; |
| // Be defensive about the contents of Entry. |
| if (IncludeDirIndex > 0 && |
| IncludeDirIndex <= Prologue.IncludeDirectories.size()) { |
| const char *IncludeDir = Prologue.IncludeDirectories[IncludeDirIndex - 1]; |
| sys::path::append(FilePath, IncludeDir); |
| } |
| sys::path::append(FilePath, FileName); |
| Result = FilePath.str(); |
| return true; |
| } |
