<div dir="ltr">I guess that <font face="monospace">clang_isDynamicCall</font> is not concerned with function calls that can be de-virtualised through optimisation (albeit fairly trivial optimisation).<br><br>I'm interested to know how you could, in general, find out when a method will be called polymorphically but would guess that it's very hard as cross-translation unit optimisation (WPO) would have an effect. Clang's AST won't have access ot the info needed to determine this (as far as I know).<br><br>Please keep me posted on progress!<br><br>Jon<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 15 May 2020 at 14:28, Borges, Matt via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11pt">Hi,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Just resending. If I am asking this question on the wrong mailing list, please le me know.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Thanks,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Matt<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">Matt Borges <<a href="mailto:matt.borges@sap.com" target="_blank">matt.borges@sap.com</a>><br>
<b>Date: </b>Friday, May 8, 2020 at 11:36 AM<br>
<b>To: </b>"<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-dev@lists.llvm.org</a>" <<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-dev@lists.llvm.org</a>><br>
<b>Subject: </b>clang_isDynamicCall always returns true for CallExpr which call virtual methods<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11pt">Hi,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">I’m visiting the AST of this simple code with libclang:<br>
<br>
</span><span style="font-size:10pt;font-family:"Courier New"">class Base</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">{</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> public:</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> virtual void Print() {}</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">};</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">class Derived : public Base</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">{</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> public:</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> virtual void Print() {}</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">};</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">void func1( Base * b )</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">{</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> b->Print();</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">}</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">void func2( Base b )</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">{</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> b.Print();</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">}</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">void func3( Base & b )</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">{</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> b.Print();</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New"">}</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">clang_isDynamicCall returns true for all three CallExpr cursors in the code. I would have expected clang_isDynamicCall to return false for the call in func2 because the call is definitely to the Print method
of Base. Is this intended behaviour? If yes, is there another way to determine whether the function call is going to be made polymorphically?</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">Thanks in advance,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">Matt</span><u></u><u></u></p>
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