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Compiler & Tools Guide
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<h1><a name="obj2asm">OBJ2ASM: Object File Disassembler</a> </h1> <p><strong>obj2asm</strong> disassembles object (.obj) files in Intel <strong>OMF</strong>, Microsoft 32 and 64 bit <strong>COFF</strong> format, Linux <strong>ELF</strong> or Mac OS X <strong>Mach-O</strong> format, and writes out the corresponding assembler source code. (<strong>dmc++</strong> generates Intel OMF format object files.) It works with the <strong>dmd</strong> D compiler, too. </p> <p>16, 32 and 64 bit Intel x86 instruction sets are supported. </p> <p><strong>obj2asm</strong> automatically recognizes the object file format and instruction set to be disassembled.</p> <p>Looking at the assembly language output of the compiler is highly useful for: </p> <ul> <li>Understanding how various language constructs are compiled.</li> <li>Trying various ways of expressing an algorithm to see which ones produce faster code.</li> <li>If a particular function needs to be rewritten in inline assembly and hand optimized for maximum speed, the <strong>obj2asm</strong> output forms a good starting point.</li> <li>Due to the large number of function calling conventions supported, sometimes it is necessary to verify that the correct convention is being used.</li> <li>Verifying correct code generation.</li> <li>Comparing output with other compilers.</li> <li>Learning assembly language.</li> </ul> <p>Compiling the file with the <strong>-gl</strong> option embeds line number information in the object file, enabling <strong>obj2asm</strong> to match the source code up with the generated assembler instructions. Compiling the file with the <strong>-g</strong> option embeds debug records in the object file, which <strong>obj2asm</strong> will format and output. </p> <h4>Syntax</h4> <p><strong>obj2asm</strong> commands have the following format:</p> <pre><strong>obj2asm</strong> [<strong>-l -o -x</strong>] <em>objectfile</em>[<strong>.obj</strong>] [<em>sourcefile</em>] [<strong>-c</strong><em>outfile</em>[<strong>.cod</strong>]] </pre> <table class="structure"><caption>Obj2asm Arguments</caption><tr><th>Arguments</th> <th>Description</th></tr> <tr><td><em>objectfile</em></td> <td>the object file to disassemble. The extension defaults to <strong>.obj</strong></td></tr> <tr><td><em>sourcefile</em></td> <td>the file compiled to produce the object file. Use this if the source file name embedded in the object file is missing or incorrect</td></tr> <tr><td><strong>-l</strong></td> <td>omit code labels in the assembly language file generated. Useful when comparing two object files; helping highlight the differences between them</td></tr> <tr><td><strong>-o</strong></td> <td>emit object code for each assembly language instruction</td></tr> <tr><td><strong>-x</strong></td> <td>emit code segment offset for each instruction</td></tr> <tr><td><strong>-c</strong><em>outfile</em></td> <td>write output to <em>outfile</em> instead of the standard output. The default extension for <em>outfile</em> is <strong>.cod</strong></td></tr> </table> <h4>Example</h4> <p>To see the code generated by compiling test.cpp, use the following commands: </p> <pre><a href="/index.cgi/speech/https://digitalmars.com/ctg/sc.html">dmc</a> -c -gl test obj2asm test </pre> <p><strong>Note:</strong> Although the output of <strong>obj2asm</strong> is in <strong>masm</strong> format, it usually requires a little editting before <strong>masm</strong> will accept it. </p> <h4>File Formats Supported</h4> <ul> <li>Tool Interface Standards (TIS) Relocatable Object Module Format (OMF) Specification Version 1.1</li> <li>Microsoft Codeview 4.0 Symbolic Debug Information Specification</li> <li><a href="https://www.digitalmars.com/d/">D programming language</a> <a href="https://www.digitalmars.com/d/abi.html#codeview">extensions to Codeview</a> </li> <li>Microsoft COFF</li> <li>Tool Interface Standard (TIS) Executable and Linking Format (ELF) Specification Version 1.2</li> <li>Mac OS X Mach-O</li> </ul> <h4>Getting Obj2asm</h4> <p><strong>obj2asm</strong> comes as part of the <a href="https://www.digitalmars.com/shop.html">C/C++ Development System</a> or the <a href="https://www.digitalmars.com/shop.html">Extended Utility Package</a>. </p> </div> <div id="footernav"> <a href="https://www.digitalmars.com/" title="digitalmars.com">Home</a> | <a href="/index.cgi/speech/https://digitalmars.com/ctg/../rtl/rtl.html" title="Runtime Library Reference">Runtime Library</a> | <a href="/index.cgi/speech/https://digitalmars.com/ctg/../ugr/ugr.html" title="IDDE Reference">IDDE Reference</a> | <a href="/index.cgi/speech/https://digitalmars.com/ctg/../stl/index.html" title="Standard Template Library">STL</a> | <a href="https://www.digitalmars.com/advancedsearch.html" title="Search Digital Mars web site">Search</a> | <a href="https://www.digitalmars.com//download/freecompiler.html" title="download C++">Download</a> | <a href="https://www.digitalmars.com/NewsGroup.html" title="Forums">Forums</a> </div> <div id="copyright"> Copyright © 1999-2022 by Digital Mars ®, All Rights Reserved | Page generated by <a href="https://dlang.org/spec/ddoc.html">Ddoc</a>. </div> </div><div class="naked_ctrl"> <form action="/index.cgi/speech" method="get" name="gate"> <p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://digitalmars.com/ctg/obj2asm.html">(->オリジナル)</a> / <label>アドレス: <input type="text" name="naked_post_url" value="https://digitalmars.com/ctg/obj2asm.html" size="22" /></label> <label>モード: <select name="naked_post_mode"> <option value="default">デフォルト</option> <option value="speech" selected="selected">音声ブラウザ</option> <option value="ruby">ルビ付き</option> <option value="contrast">配色反転</option> <option value="larger-text">文字拡大</option> <option value="mobile">モバイル</option> </select> <input type="submit" value="表示" /> </p> </form> </div> </body> </html>