<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="" applecontenteditable="true"><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 16, 2017, at 4:11 AM, Dipanjan Das via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class=""><br class=""></div>Can anybody give me any pointer on how compiler-rt, especially the sanitizers work? Do they operate on IR as any other LLVM pass? Or are they integral part of the frontend itself? I couldn't spot any documentation on the internals of compiler-rt project? What happens (sequence of actions) when I pass -fsanitizer=dataflow to clang?</div></div></blockquote><div><br class=""></div><div>Passing -fsanitize=dataflow tells clang to insert the dataflow sanitizer's instrumentation pass into the normal compilation pipeline. The instrumentation occurs at the LLVM IR level. The pass may insert calls into runtime functions which are provided by compiler-rt. Therefore, in order to link a program compiled with -fsanitize=dataflow, the appropriate runtime library from compiler-rt is required.</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="">Precisely, I intend to alter the behaviour of DFSan to suit my need.</div></div></div></blockquote><div><br class=""></div>What is your need, exactly?</div><div><br class=""></div><div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""> Therefore, I need to know how it gets integrated in the tool-chain. Initially, my idea was to insert the dfsan_set_label() calls to the IR and pass it to DFSan. However, I am not sure if it's designed to run on the source only, not on IR.<br clear="all" class=""></div></div></div></blockquote><div><br class=""></div><div>You should take a look at <span class="">lib/Transforms/Instrumentation/DataFlowSanitizer.cpp. There doesn't appear to be much done at the source level.</span></div><span class=""><br class=""></span><div>best,</div><div>vedant</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><div class=""><br class=""></div>-- <br class=""><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr" class=""><span class=""><div class=""><div dir="ltr" class=""><p class="">Thanks & Regards,</p>
<div class="">Dipanjan</div></div></div></span></div></div>
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