1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2 "http://www.w3.org/TR/html4/strict.dtd"> 3<html> 4<head> 5 <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 6 <title>Clang - Get Involved</title> 7 <link type="text/css" rel="stylesheet" href="menu.css"> 8 <link type="text/css" rel="stylesheet" href="content.css"> 9</head> 10<body> 11 12<!--#include virtual="menu.html.incl"--> 13 14<div id="content"> 15 16<h1>Open Clang Projects</h1> 17 18<p>Here are a few tasks that are available for newcomers to work on, depending 19on what your interests are. This list is provided to generate ideas, it is not 20intended to be comprehensive. Please ask on cfe-dev for more specifics or to 21verify that one of these isn't already completed. :)</p> 22 23<ul> 24<li><b>Undefined behavior checking</b>: CodeGen could 25insert runtime checks for all sorts of different undefined behaviors, from 26reading uninitialized variables, buffer overflows, and many other things. This 27checking would be expensive, but the optimizers could eliminate many of the 28checks in some cases, and it would be very interesting to test code in this mode 29for certain crowds of people. Because the inserted code is coming from clang, 30the "abort" message could be very detailed about exactly what went wrong.</li> 31 32<li><b>Improve target support</b>: The current target interfaces are heavily 33stubbed out and need to be implemented fully. See the FIXME's in TargetInfo. 34Additionally, the actual target implementations (instances of TargetInfoImpl) 35also need to be completed.</li> 36 37<li><b>Implement an tool to generate code documentation</b>: Clang's 38library-based design allows it to be used by a variety of tools that reason 39about source code. One great application of Clang would be to build an 40auto-documentation system like doxygen that generates code documentation from 41source code. The advantage of using Clang for such a tool is that the tool would 42use the same preprocessor/parser/ASTs as the compiler itself, giving it a very 43rich understanding of the code.</li> 44 45<li><b>Use clang libraries to implement better versions of existing tools</b>: 46Clang is built as a set of libraries, which means that it is possible to 47implement capabilities similar to other source language tools, improving them 48in various ways. Three examples are <a 49href="http://distcc.samba.org/">distcc</a>, the <a 50href="http://delta.tigris.org/">delta testcase reduction tool</a>, and the 51"indent" source reformatting tool. 52distcc can be improved to scale better and be more efficient. Delta could be 53faster and more efficient at reducing C-family programs if built on the clang 54preprocessor, indent could do proper formatting for complex C++ features, and it 55would be straight-forward to extend a clang-based implementation to handle 56simple structural rules like those in <a 57href="http://llvm.org/docs/CodingStandards.html#hl_earlyexit">the LLVM coding 58standards</a>.</li> 59 60<li><b>Use clang libraries to extend Ragel with a JIT</b>: <a 61href="http://research.cs.queensu.ca/~thurston/ragel/">Ragel</a> is a state 62machine compiler that lets you embed C code into state machines and generate 63C code. It would be relatively easy to turn this into a JIT compiler using 64LLVM.</li> 65 66<li><b>Self-testing using clang</b>: There are several neat ways to 67improve the quality of clang by self-testing. Some examples: 68<ul> 69 <li>Improve the reliability of AST printing and serialization by 70 ensuring that the AST produced by clang on an input doesn't change 71 when it is reparsed or unserialized. 72 73 <li>Improve parser reliability and error generation by automatically 74 or randomly changing the input checking that clang doesn't crash and 75 that it doesn't generate excessive errors for small input 76 changes. Manipulating the input at both the text and token levels is 77 likely to produce interesting test cases. 78</ul> 79</li> 80 81<li><b>Continue work on C++'11 support</b>: 82 C++'98 is feature complete, but there is still a lot of C++'11 features to 83 implement. Please see the <a href="cxx_status.html">C++ status report 84 page</a> to find out what is missing.</li> 85 86<li><b>StringRef'ize APIs</b>: A thankless but incredibly useful project is 87StringRef'izing (converting to use <tt>llvm::StringRef</tt> instead of <tt>const 88char *</tt> or <tt>std::string</tt>) various clang interfaces. This generally 89simplifies the code and makes it more efficient.</li> 90 91<li><b>Universal Driver</b>: Clang is inherently a cross compiler. We would like 92to define a new model for cross compilation which provides a great user 93experience -- it should be easy to cross compile applications, install support 94for new architectures, access different compilers and tools, and be consistent 95across different platforms. See the <a href="UniversalDriver.html">Universal 96Driver</a> web page for more information.</li> 97 98<li><b>XML Representation of ASTs</b>: Clang maintains a rich Abstract Syntax Tree that describes the program. Clang could emit an XML document that describes the program, which others tools could consume rather than being tied directly to the Clang binary.The XML representation needs to meet several requirements: 99 <ul> 100 <li><i>General</i>, so that it's able to represent C/C++/Objective-C abstractly, and isn't tied to the specific internal ASTs that Clang uses.</li> 101 <li><i>Documented</i>, with appropriate Schema against which the output of Clang's XML formatter can be verified.</li> 102 <li><i>Stable</i> across Clang versions.</li> 103 </ul></li> 104 105<li><b>Configuration Manager</b>: Clang/LLVM works on a large number of 106architectures and operating systems and can cross-compile to a similarly large 107number of configurations, but the pitfalls of chosing the command-line 108options, making sure the right sub-architecture is chosen and that the correct 109optional elements of your particular system can be a pain. 110 111<p>A tool that would investigate hosts and targets, and store the configuration 112in files that can later be used by Clang itself to avoid command-line options, 113especially the ones regarding which target options to use, would greatle alleviate 114this problem. A simple tool, with little or no dependency on LLVM itself, that 115will investigate a target architecture by probing hardware, software, libraries 116and compiling and executing code to identify all properties that would be relevant 117to command-line options (VFP, SSE, NEON, ARM vs. Thumb etc), triple settings etc.</p> 118 119<p>The first stage is to build a CFLAGS for Clang that would produce code on the 120current Host to the identified Target.</p> 121 122<p>The second stage would be to produce a configuration file (that can be used 123independently of the Host) so that Clang can read it and not need a gazillion 124of command-line options. Such file should be simple JSON / INI or anything that 125a text editor could change.</p> 126</ul> 127 128<p>If you hit a bug with clang, it is very useful for us if you reduce the code 129that demonstrates the problem down to something small. There are many ways to 130do this; ask on cfe-dev for advice.</p> 131 132</div> 133</body> 134</html> 135