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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"
#include <AK/String.h>
//#define DWARF_DEBUG
LineProgram::LineProgram(InputMemoryStream& 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 >> Bytes { &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: " << m_unit_header.length;
#endif
}
void LineProgram::parse_source_directories()
{
m_source_directories.append(".");
String directory;
while (m_stream >> directory) {
#ifdef DWARF_DEBUG
dbg() << "directory: " << directory;
#endif
m_source_directories.append(move(directory));
}
m_stream.handle_error();
m_stream.discard_or_error(1);
ASSERT(!m_stream.handle_error());
}
void LineProgram::parse_source_files()
{
m_source_files.append({ ".", 0 });
while (!m_stream.eof() && m_stream.peek_or_error()) {
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.discard_or_error(1);
ASSERT(!m_stream.handle_error());
}
void LineProgram::append_to_line_info()
{
#ifdef DWARF_DEBUG
dbg() << "appending line info: " << (void*)m_address << ", " << m_source_files[m_file_index].name << ":" << m_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*)m_address;
#endif
break;
}
case ExtendedOpcodes::SetDiscriminator: {
#ifdef DWARF_DEBUG
dbg() << "SetDiscriminator";
#endif
m_stream.discard_or_error(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*)(m_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: " << m_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: " << (m_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: " << m_source_files[m_file_index].name << ":" << m_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);
}
}
}
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