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	 8a886e0e96
			
		
	
	
		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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| 
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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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| 
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| class LineProgram {
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| public:
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|     explicit LineProgram(BufferStream& stream);
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| 
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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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| 
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|     const Vector<LineInfo>& lines() const { return m_lines; }
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| 
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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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| 
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|     void append_to_line_info();
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|     void reset_registers();
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|     BufferStream& m_stream;
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| 
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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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| 
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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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| 
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|     Vector<LineInfo> m_lines;
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| };
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