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<DIV><FONT color=#000080 size=2 face=Verdana>Hi, John Criswell!</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV style="TEXT-INDENT: 2em"><FONT color=#000080>Thank you for your detailed
and fast reply.</FONT></DIV>
<DIV style="TEXT-INDENT: 2em"><FONT color=#000080>I will update my proposal
following your suggestion as soon as possible.</FONT></DIV>
<DIV style="TEXT-INDENT: 2em"><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Best Regards!</FONT></DIV>
<DIV><FONT color=#000080>Qiuping</FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Verdana></FONT> </DIV>
<DIV><FONT color=#000080 size=2 face=Verdana></FONT> </DIV>
<DIV><FONT color=#c0c0c0 size=2 face=Verdana>2010-04-08 </FONT></DIV><FONT
color=#000080 size=2 face=Verdana>
<HR style="WIDTH: 100px" align=left color=#b5c4df SIZE=1>
</FONT>
<DIV><FONT color=#c0c0c0 size=2 face=Verdana><SPAN>yiqiuping1986</SPAN>
</FONT></DIV>
<HR color=#b5c4df SIZE=1>
<DIV><FONT size=2 face=Verdana><STRONG>发件人：</STRONG> John Criswell </FONT></DIV>
<DIV><FONT size=2 face=Verdana><STRONG>发送时间：</STRONG> 2010-04-07 23:57:29
</FONT></DIV>
<DIV><FONT size=2 face=Verdana><STRONG>收件人：</STRONG> yiqiuping1986 </FONT></DIV>
<DIV><FONT size=2 face=Verdana><STRONG>抄送：</STRONG> llvmdev </FONT></DIV>
<DIV><FONT size=2 face=Verdana><STRONG>主题：</STRONG> Re: summer of code idea—
update the SAFECode project to the new LLVM API </FONT></DIV>
<DIV><FONT size=2 face=Verdana></FONT> </DIV>
<DIV><FONT size=2 face=Verdana>
<DIV>yiqiuping1986 wrote:</DIV>
<DIV>> Hi， John Criswell！</DIV>
<DIV>> You have said to me that SAFECode had not been maintained for several</DIV>
<DIV>> years,</DIV>
<DIV></DIV>
<DIV>Just to clarify, SAFECode *has* been and *is* maintained (primarily by</DIV>
<DIV>me). The release_26 branch in the SVN repository works with LLVM 2.6,</DIV>
<DIV>and mainline is working (with some regressions) with the upcoming LLVM</DIV>
<DIV>2.7. You can subscribe to the SVA Commits mailing list</DIV>
<DIV>(http://lists.cs.uiuc.edu/mailman/listinfo/sva-commits) to get email</DIV>
<DIV>whenever a commit is made to SAFECode.</DIV>
<DIV></DIV>
<DIV>However, there is an inter-procedural static array bounds checking pass</DIV>
<DIV>that comprises a small component of SAFECode. It is an optional</DIV>
<DIV>component, so SAFECode works without it, but SAFECode would work better</DIV>
<DIV>if this static array bounds checking pass were working.</DIV>
<DIV></DIV>
<DIV>This inter-procedural static array bounds checking pass in SAFECode has</DIV>
<DIV>not been maintained and needs to 1) be updated to work with LLVM</DIV>
<DIV>2.6/2.7; 2) have its bugs fixed; and 3) improved so that it has better</DIV>
<DIV>performance (i.e., no repeated fork()/exec() for constraint solving).</DIV>
<DIV></DIV>
<DIV></DIV>
<DIV></DIV>
<DIV>> now I have submitted my proposal for updating the SAFCode project to</DIV>
<DIV>> the new LLVM APIs.</DIV>
<DIV>> If you are still interested in the topic and willing to guid my</DIV>
<DIV>> project, I will be very happy.</DIV>
<DIV>> Now I'm waiting for you comments.</DIV>
<DIV>> Here is my proposal:</DIV>
<DIV>> http://socghop.appspot.com/gsoc/student_proposal/show/google/gsoc2010/easyqiu/t127038894856</DIV>
<DIV></DIV>
<DIV>Looking back at my previous email, I see that I was unclear. SAFECode,</DIV>
<DIV>as a whole, is up-to-date with LLVM. However, it is missing its static</DIV>
<DIV>array bounds checking pass (because that specific pass has not been</DIV>
<DIV>maintained). What I was suggesting is that, as a GSoC project, you could</DIV>
<DIV>update the static array bounds checking code from the SAFECode project.</DIV>
<DIV></DIV>
<DIV>With that in mind, here is what I think you should do:</DIV>
<DIV></DIV>
<DIV>1) Update your "Check bounds overflow bugs in C programs based on LLVM"</DIV>
<DIV>proposal</DIV>
<DIV>(http://socghop.appspot.com/gsoc/student_proposal/show/google/gsoc2010/easyqiu/t126993884556).</DIV>
<DIV>In it, state that</DIV>
<DIV>a) you are specifically interested in implementing *static* array bounds</DIV>
<DIV>checking</DIV>
<DIV>b) there is old code in the SAFECode project which you may reuse to</DIV>
<DIV>build your static array bounds checking pass</DIV>
<DIV>c) you will investigate whether any of the static array bounds checking</DIV>
<DIV>code in SAFECode is useful. If it is, you can reuse it. Otherwise, you</DIV>
<DIV>will develop something new.</DIV>
<DIV>d) remove the comment about Edwin Torok's pass being intra-procedural.</DIV>
<DIV>He has told us (or at least me) that his analysis is inter-procedural.</DIV>
<DIV>e) you can list me as a potential mentor, if you like.</DIV>
<DIV></DIV>
<DIV>2) Delete the "Update the SAFECode project to the new LLVM API"</DIV>
<DIV>proposal. SAFECode, as a whole, works with LLVM 2.6/2.7. Reusing the old</DIV>
<DIV>static array bounds checking pass from SAFECode can be merged into your</DIV>
<DIV>bounds checking proposal (as I stated above).</DIV>
<DIV></DIV>
<DIV>3) In all of your proposals, you should state why the mentor would be a</DIV>
<DIV>good mentor. In my case, you can state that I am a past LLVM contributor</DIV>
<DIV>and that I am the primary maintainer of the SAFECode project (which uses</DIV>
<DIV>LLVM extensively).</DIV>
<DIV></DIV>
<DIV>4) In your ABCD proposal, did you copy the text describing the ABCD</DIV>
<DIV>algorithm from the ABCD paper? If so, don't do that; describe the</DIV>
<DIV>algorithm in your own words (even if your English isn't perfect). It</DIV>
<DIV>will show that you understand the algorithm and prevent you from being</DIV>
<DIV>accused of plagiarism.</DIV>
<DIV></DIV>
<DIV>5) Cite sources. If your proposal states that you are going to implement</DIV>
<DIV>an algorithm described in a paper, specify exactly which paper it is.</DIV>
<DIV>That way, the proposal reviewer can look at the paper.</DIV>
<DIV></DIV>
<DIV>-- John T.</DIV>
<DIV></DIV>
<DIV></DIV>
<DIV></DIV>
<DIV>> 2010-04-07</DIV>
<DIV>> ------------------------------------------------------------------------</DIV>
<DIV>> yiqiuping1986</DIV>
<DIV>> ------------------------------------------------------------------------</DIV>
<DIV>> *发件人：* John Criswell</DIV>
<DIV>> *发送时间：* 2010-03-30 22:42:53</DIV>
<DIV>> *收件人：* John Regehr</DIV>
<DIV>> *抄送：* 易秋萍; llvmdev@cs.uiuc.edu</DIV>
<DIV>> *主题：* Re: [LLVMdev]summer_of_code_idea_—_checking_bounds_overflow_bugs</DIV>
<DIV>> John Regehr wrote:</DIV>
<DIV>> > Qiuping,</DIV>
<DIV>> ></DIV>
<DIV>> > Have you looked at what has already been done? I would expect that</DIV>
<DIV>> taking</DIV>
<DIV>> > previous work such as this:</DIV>
<DIV>> ></DIV>
<DIV>> > http://llvm.org/pubs/2006-05-24-SAFECode-BoundsCheck.html</DIV>
<DIV>> ></DIV>
<DIV>> > and integrating into current LLVM would be a better idea than starting</DIV>
<DIV>> > over.</DIV>
<DIV>> ></DIV>
<DIV>> This code is publicly available from the SAFECode project (see</DIV>
<DIV>> http://safecode.cs.illinois.edu to see how to get it). However, it has</DIV>
<DIV>> not been maintained well over the years and is currently disabled.</DIV>
<DIV>> Getting it to work again with LLVM 2.6 or replacing it with something</DIV>
<DIV>> better would be nice.</DIV>
<DIV>> I'm writing up a response to this project idea as I'm willing to mentor</DIV>
<DIV>> it; I'll send it out shortly.</DIV>
<DIV>> -- John T.</DIV>
<DIV>> > John</DIV>
<DIV>> ></DIV>
<DIV>> ></DIV>
<DIV>> > On Tue, 30 Mar 2010, ??? wrote:</DIV>
<DIV>> ></DIV>
<DIV>> ></DIV>
<DIV>> >> Hi,</DIV>
<DIV>> >></DIV>
<DIV>> >> Some days ago I am interested in detecting undefined behaviors</DIV>
<DIV>> >></DIV>
<DIV>> >> in C programs based on Clang. After several days? investigation, I</DIV>
<DIV>> think</DIV>
<DIV>> >></DIV>
<DIV>> >> checking bounds overflow bugs is more interesting, because bounds</DIV>
<DIV>> >></DIV>
<DIV>> >> overflow is one of the most frequently encountered errors in C</DIV>
<DIV>> programs.</DIV>
<DIV>> >></DIV>
<DIV>> >> For example, performing pointer arithmetic without checking bounds</DIV>
<DIV>> >></DIV>
<DIV>> >> can cause bounds overflow. To increase the accuracy of finding bugs,</DIV>
<DIV>> >></DIV>
<DIV>> >> I want to write several passes, based on slicing, inline and summary</DIV>
<DIV>> >> function</DIV>
<DIV>> >></DIV>
<DIV>> >> / (partial) transition function, to implement intre-procedural</DIV>
<DIV>> analysis.</DIV>
<DIV>> >></DIV>
<DIV>> >> Does some person have interest in the project? I need a mentor,</DIV>
<DIV>> >></DIV>
<DIV>> >> and wait for your reply.</DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> >> Best Reagards!</DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> >> Qiuping Yi</DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> >></DIV>
<DIV>> > ></DIV>
<DIV>> _______________________________________________</DIV>
<DIV>> LLVM Developers mailing list</DIV>
<DIV>> LLVMdev@cs.uiuc.edu http://llvm.cs.uiuc.edu</DIV>
<DIV>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</DIV>
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