<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">I don't like any option that requires the JIT client to specify the CPU type when JITing with intent to run in-process (i.e. the default). This just adds even more noise to the already-confusing MCJIT APIs.</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><p style="color:#000;">On April 22, 2014 at 9:30:48 AM, Eric Christopher (<a href="mailto:echristo@gmail.com">echristo@gmail.com</a>) wrote:</p> <div><blockquote type="cite" class="clean_bq" style="color: rgb(0, 0, 0); font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255);"><span><div><div></div><div>>> To fix this we could:<br>>> 1.) Extend the C interface to also specify the CPU type and warn JIT clients that don’t specify a CPU for ARM64<br>> This looks like the right approach to me.<br>> The clients of the backend should not rely on any default CPU.</div></div></span></blockquote></div><p>It's the wrong approach. The JIT default is to produce code that runs in the process. The client of the C interface shouldn't have to tell LLVM what the right processor is for the process in which LLVM is running and for which LLVM is generating code.</p><div><div><blockquote type="cite" class="clean_bq" style="color: rgb(0, 0, 0); font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255);"><span><div><div><br>><br>> What is the current behavior on X86?<br>>><br>>> 3.) Every JIT client has to add the target processor attribute to the IR<br>> That sounds like a good safe belt, especially to reproduce failures (see http://llvm.org/bugs/show_bug.cgi?id=19483). That said, how this attribute is propagated?<br>> In particular does ARM64 backend do the right thing if you set it.<br>></div></div></span></blockquote></div><p>I'm not sure I understand this option.</p><div><div><blockquote type="cite" class="clean_bq" style="color: rgb(0, 0, 0); font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255);"><span><div><div><br><br>I definitely like both of these options...<br><br>>> 4.) Revert this change<br>> This change has been actively discussed on the mailing list (http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140414/212869.html) and IRC. This seemed to be the best approach especially with the merge with aarch64.<br>><br>>><br><br>and would be actively against this.</div></div></span></blockquote></div><p>In the future, would you also be actively against reverting other changes that break WebKit?</p><p>-Filip</p><p><br></p><div><blockquote type="cite" class="clean_bq" style="color: rgb(0, 0, 0); font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255);"><span><div><div><br><br>-eric<br><br>_______________________________________________<br>llvm-commits mailing list<br>llvm-commits@cs.uiuc.edu<br>http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits<br></div></div></span></blockquote></div></div></div></body></html>