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| <h1>Open Clang Projects</h1> |
| |
| <p>Here are a few tasks that are available for newcomers to work on, depending |
| on what your interests are. This list is provided to generate ideas, it is not |
| intended to be comprehensive. Please ask on cfe-dev for more specifics or to |
| verify that one of these isn't already completed. :)</p> |
| |
| <ul> |
| <li><b>Compile your favorite C/ObjC project with Clang</b>: |
| Clang's type-checking and code generation is very close to complete (but not bug free!) for C and Objective-C. We appreciate all reports of code that is |
| rejected or miscompiled by the front-end. If you notice invalid code that is not rejected, or poor diagnostics when code is rejected, that is also very important to us. For make-based projects, |
| the <a href="get_started.html#ccc"><code>ccc</code></a> driver works as a drop-in replacement for GCC.</li> |
| |
| <li><b>Overflow detection</b>: an interesting project would be to add a -ftrapv |
| compilation mode that causes -emit-llvm to generate overflow tests for all |
| signed integer arithmetic operators, and call abort if they overflow. Overflow |
| is undefined in C and hard for people to reason about. LLVM IR also has |
| intrinsics for generating arithmetic with overflow checks directly.</li> |
| |
| <li><b>Undefined behavior checking</b>: similar to adding -ftrapv, codegen could |
| insert runtime checks for all sorts of different undefined behaviors, from |
| reading uninitialized variables, buffer overflows, and many other things. This |
| checking would be expensive, but the optimizers could eliminate many of the |
| checks in some cases, and it would be very interesting to test code in this mode |
| for certain crowds of people. Because the inserted code is coming from clang, |
| the "abort" message could be very detailed about exactly what went wrong.</li> |
| |
| <li><b>Continue work on C++ support</b>: Implementing all of C++ is a very big |
| job, but there are lots of little pieces that can be picked off and implemented. |
| See the <a href="cxx_status.html">C++ status report page</a> to find out what is |
| missing and what is already at least partially supported.</li> |
| |
| <li><b>Improve target support</b>: The current target interfaces are heavily |
| stubbed out and need to be implemented fully. See the FIXME's in TargetInfo. |
| Additionally, the actual target implementations (instances of TargetInfoImpl) |
| also need to be completed.</li> |
| |
| <li><b>Implement an tool to generate code documentation</b>: Clang's |
| library-based design allows it to be used by a variety of tools that reason |
| about source code. One great application of Clang would be to build an |
| auto-documentation system like doxygen that generates code documentation from |
| source code. The advantage of using Clang for such a tool is that the tool would |
| use the same preprocessor/parser/ASTs as the compiler itself, giving it a very |
| rich understanding of the code.</li> |
| |
| <li><b>Use clang libraries to implement better versions of existing tools</b>: |
| Clang is built as a set of libraries, which means that it is possible to |
| implement capabilities similar to other source language tools, improving them |
| in various ways. Two examples are <a href="http://distcc.samba.org/">distcc</a> |
| and the <a href="http://delta.tigris.org/">delta testcase reduction tool</a>. |
| The former can be improved to scale better and be more efficient. The later |
| could also be faster and more efficient at reducing C-family programs if built |
| on the clang preprocessor.</li> |
| |
| <li><b>Use clang libraries to extend Ragel with a JIT</b>: <a |
| href="http://research.cs.queensu.ca/~thurston/ragel/">Ragel</a> is a state |
| machine compiler that lets you embed C code into state machines and generate |
| C code. It would be relatively easy to turn this into a JIT compiler using |
| LLVM.</li> |
| |
| <li><b>Self-testing using clang</b>: There are several neat ways to |
| improve the quality of clang by self-testing. Some examples: |
| <ul> |
| <li>Improve the reliability of AST printing and serialization by |
| ensuring that the AST produced by clang on an input doesn't change |
| when it is reparsed or unserialized. |
| |
| <li>Improve parser reliability and error generation by automatically |
| or randomly changing the input checking that clang doesn't crash and |
| that it doesn't generate excessive errors for small input |
| changes. Manipulating the input at both the text and token levels is |
| likely to produce interesting test cases. |
| </ul> |
| </li> |
| |
| </ul> |
| |
| <p>If you hit a bug with clang, it is very useful for us if you reduce the code |
| that demonstrates the problem down to something small. There are many ways to |
| do this; ask on cfe-dev for advice.</p> |
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