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8a886e0e96
DWARF line number information, if generated, is stored in the .debug_line section of an object file. The information is encoded as instructions for a VM that is defined in the DWARF specification. By executing these instructions, we can extract the encoded line number information.
113 lines
3.2 KiB
C++
113 lines
3.2 KiB
C++
/*
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* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/BufferStream.h>
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#include <AK/Vector.h>
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class LineProgram {
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public:
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explicit LineProgram(BufferStream& stream);
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struct LineInfo {
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u32 address { 0 };
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String file;
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size_t line { 0 };
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};
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const Vector<LineInfo>& lines() const { return m_lines; }
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private:
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void parse_unit_header();
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void parse_source_directories();
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void parse_source_files();
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void run_program();
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void append_to_line_info();
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void reset_registers();
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void handle_extended_opcode();
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void handle_standard_opcode(u8 opcode);
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void handle_sepcial_opcode(u8 opcode);
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struct [[gnu::packed]] UnitHeader32
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{
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u32 length;
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u16 version;
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u32 header_length;
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u8 min_instruction_length;
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u8 default_is_stmt;
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i8 line_base;
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u8 line_range;
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u8 opcode_base;
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u8 std_opcode_lengths[12];
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};
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enum StandardOpcodes {
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Copy = 1,
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AdvancePc,
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AdvanceLine,
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SetFile,
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SetColumn,
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NegateStatement,
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SetBasicBlock,
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ConstAddPc,
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FixAdvancePc,
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SetProlougeEnd,
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SetEpilogueBegin,
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SetIsa
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};
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enum ExtendedOpcodes {
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EndSequence = 1,
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SetAddress,
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DefineFile,
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SetDiscriminator,
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};
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struct FileEntry {
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String name;
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size_t directory_index { 0 };
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};
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static constexpr u16 DWARF_VERSION = 3;
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static constexpr u8 SPECIAL_OPCODES_BASE = 13;
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BufferStream& m_stream;
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size_t m_unit_offset { 0 };
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UnitHeader32 m_unit_header {};
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Vector<String> m_source_directories;
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Vector<FileEntry> m_source_files;
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// The registers of the "line program" virtual machine
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u32 m_address { 0 };
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size_t m_line { 0 };
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size_t m_file_index { 0 };
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bool m_is_statement { false };
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Vector<LineInfo> m_lines;
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};
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