<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On Sep 19, 2013, at 6:25 PM, Kaylor, Andrew <<a href="mailto:andrew.kaylor@intel.com">andrew.kaylor@intel.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">I’ve been working on the MCJIT interface today. There are a lot of ugly things there as a result of sharing a base class with the old JIT engine.</span></div></div></div></blockquote><div><br></div>Very much so. I’ve often wondered whether it would have been better to split off an entirely new class originally to avoid this sort of thing. Probably better the current way, but ugh.</div><div><span style="color: rgb(31, 73, 125); font-family: Calibri, sans-serif; font-size: 11pt;"> </span><br><blockquote type="cite" dir="auto"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">With regard to the getPointerToX functions, I was thing about adding new methods getXAddress that return uint64_t values and calling the old ones deprecated. I’m not sure that helps with the C API, but I thought I’d mention it.<o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"></div></div></div></blockquote><div><br></div><div>That’s a really good idea. For the C API, we just expose those instead. We should put a bit of thought into the inputs there, though. The current interfaces use pointers from the IR (Value* and such), but that’s not long term viable, as there’s nothing in the MCJIT which requires that the lifetime of the Module be >= the lifetime of the resultant compiled code. I’d much rather the interfaces be via name, but that has other complications (platform specific name mangling, etc..).</div><br><blockquote type="cite" dir="auto"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"> </span><span style="color: rgb(31, 73, 125); font-family: Calibri, sans-serif; font-size: 11pt;">Is there any reason not to have this function return a uint64_t? Even the void pointer would need to be cast to something else to be useful.</span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"></div></div></div></blockquote><div><br></div><div>Just that there can be arches w/ > 64 bit pointers (fat pointers on x86, perhaps). I think that’s a reasonable limitation, though.</div><br><blockquote type="cite" dir="auto"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">BTW, the current implementation of MCJIT::runFunction() will definitely not work if the target is remote.<o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"></div></div></div></blockquote><div><br></div><div>Yeah, it’s totally broken. I’m in favor of nuking it entirely.</div><br><blockquote type="cite" dir="auto"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"> </span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">-Andy<o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"> </span></div><div><div style="border-style: solid none none; border-top-color: rgb(181, 196, 223); border-top-width: 1pt; padding: 3pt 0in 0in;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif;">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif;"><span class="Apple-converted-space"> </span><a href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a> [<a href="mailto:llvm-commits-bounces@cs.uiuc.edu">mailto:llvm-commits-bounces@cs.uiuc.edu</a>]<span class="Apple-converted-space"> </span><b>On Behalf Of<span class="Apple-converted-space"> </span></b>Jim Grosbach<br><b>Sent:</b><span class="Apple-converted-space"> </span>Thursday, September 19, 2013 2:27 PM<br><b>To:</b><span class="Apple-converted-space"> </span>Filip Pizlo<br><b>Cc:</b><span class="Apple-converted-space"> </span><a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br><b>Subject:</b><span class="Apple-converted-space"> </span>Re: [llvm] r191030 - llvm-c: Add LLVMGetPointerToFunction<o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">On Sep 19, 2013, at 2:04 PM, Filip Pizlo <<a href="mailto:fpizlo@apple.com" style="color: purple; text-decoration: underline;">fpizlo@apple.com</a>> wrote:<o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><br><br><o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">On Sep 19, 2013, at 1:49 PM, Jim Grosbach <<a href="mailto:grosbach@apple.com" style="color: purple; text-decoration: underline;">grosbach@apple.com</a>> wrote:<o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br>On Sep 19, 2013, at 1:46 PM, Filip Pizlo <<a href="mailto:fpizlo@apple.com" style="color: purple; text-decoration: underline;">fpizlo@apple.com</a>> wrote:<o:p></o:p></span></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br><br><o:p></o:p></span></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">How is that different from LLVMGetPointerToGlobal()?<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"> </span></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">It’s not. That’s broken, too.<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br><br><o:p></o:p></span></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">And I agree that this should work. It's great that the JIT could be used for remote execution, but some clients will never use the JIT in that fashion. They will just want a void*.<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"> </span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">Then they will use a memory manager that can make additional guarantees such as the opaque uint64_t value is actual just a bitcasted local pointer which can be safely cast back to void* or whatever. That’s a client-process usage, however, and not a guarantee of the JIT API.<o:p></o:p></span></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">Are you saying that if a LLVM C API client doesn't install a custom memory manager, then the MCJIT is semantically permitted to JIT the code into a remote process?<o:p></o:p></div></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">No, I’m saying the API has to be semantically rich enough to be agnostic about remote vs. local. That’s a function of the memory manager interface. The default memory manager does indeed to local currently. I have mixed feelings about making that an explicit guarantee.<o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><br><br><o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">Currently the C API has no facility for asking for code to be JITed into something remote, and it seems like it would be a bug if the JIT did this without the client asking for it. It makes far more sense to me that the C API continues to have a hard constraint that JITing is local, and that the end result is a function that lives in your address space.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">I strongly disagree. The C API is about exposing functionality, not imposing additional constraints.<o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><o:p> </o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;">-Jim<o:p></o:p></div></div><div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;"><blockquote style="margin-top: 5pt; margin-bottom: 5pt;"><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br><br><o:p></o:p></span></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"> </span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"> </span></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">On Sep 19, 2013, at 1:36 PM, Eric Christopher <<a href="mailto:echristo@gmail.com" style="color: purple; text-decoration: underline;">echristo@gmail.com</a>> wrote:<o:p></o:p></span></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br><br><o:p></o:p></span></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">Hrm. That's a good point and one I hadn't thought about... what's the<br>best way forward here? There's definitely a useful need in getting a<br>void * to a function out of the JIT from the C level.<br><br>-eric<br><br>On Thu, Sep 19, 2013 at 1:30 PM, Jim Grosbach <<a href="mailto:grosbach@apple.com" style="color: purple; text-decoration: underline;">grosbach@apple.com</a>> wrote:<br><br><o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">This isn’t going to work when the execution target isn’t local. The pointer to the function is in the executing process address space and this returns a pointer in the compiler’s address space.<br><br>That’s a fundamental problem with the old JIT, and is semi-baked into the ExecutionEngine API, unfortunately, and cleaning that up is going to be painful. We shouldn’t, however, make the problem worse.<br><br>-Jim<br><br>On Sep 19, 2013, at 12:55 PM, Anders Waldenborg <<a href="mailto:anders@0x63.nu" style="color: purple; text-decoration: underline;">anders@0x63.nu</a>> wrote:<br><br><br><o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;">Author: andersg<br>Date: Thu Sep 19 14:55:06 2013<br>New Revision: 191030<br><br>URL:<span class="apple-converted-space"> </span><a href="http://llvm.org/viewvc/llvm-project?rev=191030&view=rev" style="color: purple; text-decoration: underline;">http://llvm.org/viewvc/llvm-project?rev=191030&view=rev</a><br>Log:<br>llvm-c: Add LLVMGetPointerToFunction<br><br>Differential Revision:<span class="apple-converted-space"> </span><a href="http://llvm-reviews.chandlerc.com/D1715" style="color: purple; text-decoration: underline;">http://llvm-reviews.chandlerc.com/D1715</a><br><br><br>Modified:<br> llvm/trunk/include/llvm-c/ExecutionEngine.h<br> llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp<br><br>Modified: llvm/trunk/include/llvm-c/ExecutionEngine.h<br>URL:<span class="apple-converted-space"> </span><a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm-c/ExecutionEngine.h?rev=191030&r1=191029&r2=191030&view=diff" style="color: purple; text-decoration: underline;">http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm-c/ExecutionEngine.h?rev=191030&r1=191029&r2=191030&view=diff</a><br>==============================================================================<br>--- llvm/trunk/include/llvm-c/ExecutionEngine.h (original)<br>+++ llvm/trunk/include/llvm-c/ExecutionEngine.h Thu Sep 19 14:55:06 2013<br>@@ -141,6 +141,8 @@ LLVMGenericValueRef LLVMRunFunction(LLVM<br> unsigned NumArgs,<br> LLVMGenericValueRef *Args);<br><br>+void *LLVMGetPointerToFunction(LLVMExecutionEngineRef EE, LLVMValueRef F);<br>+<br>void LLVMFreeMachineCodeForFunction(LLVMExecutionEngineRef EE, LLVMValueRef F);<br><br>void LLVMAddModule(LLVMExecutionEngineRef EE, LLVMModuleRef M);<br><br>Modified: llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp<br>URL:<span class="apple-converted-space"> </span><a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp?rev=191030&r1=191029&r2=191030&view=diff" style="color: purple; text-decoration: underline;">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp?rev=191030&r1=191029&r2=191030&view=diff</a><br>==============================================================================<br>--- llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp (original)<br>+++ llvm/trunk/lib/ExecutionEngine/ExecutionEngineBindings.cpp Thu Sep 19 14:55:06 2013<br>@@ -276,6 +276,10 @@ LLVMGenericValueRef LLVMRunFunction(LLVM<br> return wrap(Result);<br>}<br><br>+void *LLVMGetPointerToFunction(LLVMExecutionEngineRef EE, LLVMValueRef F) {<br>+ return unwrap(EE)->getPointerToFunction(unwrap<Function>(F));<br>+}<br>+<br>void LLVMFreeMachineCodeForFunction(LLVMExecutionEngineRef EE, LLVMValueRef F) {<br> unwrap(EE)->freeMachineCodeForFunction(unwrap<Function>(F));<br>}<br><br><br>_______________________________________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@cs.uiuc.edu" style="color: purple; text-decoration: underline;">llvm-commits@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" style="color: purple; text-decoration: underline;">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br><br>_______________________________________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@cs.uiuc.edu" style="color: purple; text-decoration: underline;">llvm-commits@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" style="color: purple; text-decoration: underline;">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><o:p></o:p></span></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><span style="font-size: 9pt; font-family: Helvetica, sans-serif;"><br>_______________________________________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@cs.uiuc.edu" style="color: purple; text-decoration: underline;">llvm-commits@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" style="color: purple; text-decoration: underline;">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a></span></div></div></div></div></div></blockquote></blockquote></div></div></div></blockquote></div><br></body></html>