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-rw-r--r--Libraries/LibDebug/Dwarf/LineProgram.cpp247
1 files changed, 247 insertions, 0 deletions
diff --git a/Libraries/LibDebug/Dwarf/LineProgram.cpp b/Libraries/LibDebug/Dwarf/LineProgram.cpp
new file mode 100644
index 0000000000..2bc629daff
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+++ b/Libraries/LibDebug/Dwarf/LineProgram.cpp
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+/*
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "LineProgram.h"
+
+LineProgram::LineProgram(BufferStream& stream)
+ : m_stream(stream)
+{
+ m_unit_offset = m_stream.offset();
+ parse_unit_header();
+ parse_source_directories();
+ parse_source_files();
+ run_program();
+}
+
+void LineProgram::parse_unit_header()
+{
+ m_stream.read_raw((u8*)&m_unit_header, sizeof(m_unit_header));
+
+ ASSERT(m_unit_header.version == DWARF_VERSION);
+ ASSERT(m_unit_header.opcode_base == SPECIAL_OPCODES_BASE);
+
+#ifdef DWARF_DEBUG
+ dbg() << "unit length: " << unit_header.length;
+#endif
+}
+
+void LineProgram::parse_source_directories()
+{
+ m_source_directories.append(".");
+ while (m_stream.peek()) {
+ String directory;
+ m_stream >> directory;
+#ifdef DWARF_DEBUG
+ dbg() << "directory: " << directory;
+#endif
+ m_source_directories.append(move(directory));
+ }
+ m_stream.advance(1);
+}
+
+void LineProgram::parse_source_files()
+{
+ m_source_files.append({ ".", 0 });
+ while (m_stream.peek()) {
+ String file_name;
+ m_stream >> file_name;
+ size_t directory_index = 0;
+ m_stream.read_LEB128_unsigned(directory_index);
+ size_t _unused = 0;
+ m_stream.read_LEB128_unsigned(_unused); // skip modification time
+ m_stream.read_LEB128_unsigned(_unused); // skip file size
+#ifdef DWARF_DEBUG
+ dbg() << "file: " << file_name << ", directory index: " << directory_index;
+#endif
+ m_source_files.append({ file_name, directory_index });
+ }
+ m_stream.advance(1);
+ ASSERT(!m_stream.handle_read_failure());
+}
+
+void LineProgram::append_to_line_info()
+{
+#ifdef DWARF_DEBUG
+ dbg() << "appending line info: " << (void*)address << ", " << files[file_index].name << ":" << line;
+#endif
+ if (!m_is_statement)
+ return;
+
+ String directory = m_source_directories[m_source_files[m_file_index].directory_index];
+ String full_path = String::format("%s/%s", directory.characters(), m_source_files[m_file_index].name.characters());
+ m_lines.append({ m_address, full_path, m_line });
+}
+
+void LineProgram::reset_registers()
+{
+ m_address = 0;
+ m_line = 1;
+ m_file_index = 1;
+ m_is_statement = m_unit_header.default_is_stmt == 1;
+}
+
+void LineProgram::handle_extended_opcode()
+{
+ size_t length = 0;
+ m_stream.read_LEB128_unsigned(length);
+
+ u8 sub_opcode = 0;
+ m_stream >> sub_opcode;
+
+ switch (sub_opcode) {
+ case ExtendedOpcodes::EndSequence: {
+ append_to_line_info();
+ reset_registers();
+ break;
+ }
+ case ExtendedOpcodes::SetAddress: {
+ ASSERT(length == sizeof(size_t) + 1);
+ m_stream >> m_address;
+#ifdef DWARF_DEBUG
+ dbg() << "SetAddress: " << (void*)address;
+#endif
+ break;
+ }
+ case ExtendedOpcodes::SetDiscriminator: {
+#ifdef DWARF_DEBUG
+ dbg() << "SetDiscriminator";
+#endif
+ m_stream.advance(1);
+ break;
+ }
+ default:
+#ifdef DWARF_DEBUG
+ dbg() << "offset: " << (void*)m_stream.offset();
+#endif
+ ASSERT_NOT_REACHED();
+ }
+}
+void LineProgram::handle_standard_opcode(u8 opcode)
+{
+ switch (opcode) {
+ case StandardOpcodes::Copy: {
+ append_to_line_info();
+ break;
+ }
+ case StandardOpcodes::AdvancePc: {
+ size_t operand = 0;
+ m_stream.read_LEB128_unsigned(operand);
+ size_t delta = operand * m_unit_header.min_instruction_length;
+#ifdef DWARF_DEBUG
+ dbg() << "AdvnacePC by: " << delta << " to: " << (void*)(address + delta);
+#endif
+ m_address += delta;
+ break;
+ }
+ case StandardOpcodes::SetFile: {
+ size_t new_file_index = 0;
+ m_stream.read_LEB128_unsigned(new_file_index);
+#ifdef DWARF_DEBUG
+ dbg() << "SetFile: new file index: " << new_file_index;
+#endif
+ m_file_index = new_file_index;
+ break;
+ }
+ case StandardOpcodes::SetColumn: {
+ // not implemented
+#ifdef DWARF_DEBUG
+ dbg() << "SetColumn";
+#endif
+ size_t new_column;
+ m_stream.read_LEB128_unsigned(new_column);
+
+ break;
+ }
+ case StandardOpcodes::AdvanceLine: {
+ ssize_t line_delta;
+ m_stream.read_LEB128_signed(line_delta);
+ // dbg() << "line_delta: " << line_delta;
+ ASSERT(line_delta >= 0 || m_line >= (size_t)(-line_delta));
+ m_line += line_delta;
+#ifdef DWARF_DEBUG
+ dbg() << "AdvanceLine: " << line;
+#endif
+ break;
+ }
+ case StandardOpcodes::NegateStatement: {
+#ifdef DWARF_DEBUG
+ dbg() << "NegateStatement";
+#endif
+ m_is_statement = !m_is_statement;
+ break;
+ }
+ case StandardOpcodes::ConstAddPc: {
+ u8 adjusted_opcode = 255 - SPECIAL_OPCODES_BASE;
+ ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range) * m_unit_header.min_instruction_length;
+ address_increment *= m_unit_header.min_instruction_length;
+#ifdef DWARF_DEBUG
+ dbg() << "ConstAddPc: advance pc by: " << address_increment << " to: " << (address + address_increment);
+#endif
+ m_address += address_increment;
+ break;
+ }
+ default:
+ ASSERT_NOT_REACHED();
+ }
+}
+void LineProgram::handle_sepcial_opcode(u8 opcode)
+{
+ u8 adjusted_opcode = opcode - SPECIAL_OPCODES_BASE;
+ ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range) * m_unit_header.min_instruction_length;
+ ssize_t line_increment = m_unit_header.line_base + (adjusted_opcode % m_unit_header.line_range);
+
+ m_address += address_increment;
+ m_line += line_increment;
+
+#ifdef DWARF_DEBUG
+ dbg() << "Special adjusted_opcode: " << adjusted_opcode << ", delta_address: " << address_increment << ", delta_line: " << line_increment;
+ dbg() << "Address is now:" << (void*)m_address << ", and line is: " << source_files[m_file_index].name << ":" << line;
+#endif
+
+ append_to_line_info();
+}
+
+void LineProgram::run_program()
+{
+ reset_registers();
+
+ while ((size_t)m_stream.offset() < m_unit_offset + sizeof(u32) + m_unit_header.length) {
+ u8 opcode = 0;
+ m_stream >> opcode;
+
+#ifdef DWARF_DEBUG
+ dbg() << (void*)(m_stream.offset() - 1) << ": opcode: " << opcode;
+#endif
+
+ if (opcode == 0) {
+ handle_extended_opcode();
+ } else if (opcode >= 1 && opcode <= 12) {
+ handle_standard_opcode(opcode);
+ } else {
+ handle_sepcial_opcode(opcode);
+ }
+ }
+}