<div dir="ltr"><div><div dir="auto">Hi Paulr</div><div dir="auto"><br></div><div>Thanks for your very useful and quick reply. Below is my response.</div><div><br></div><div><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Are the functions emitted to the final binary? <span style="color:rgb(31,73,125);font-family:Calibri,sans-serif;font-size:14.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">If a function is not used, there might not be any object code for it in the final binary. Naturally there would be no entry in the line table in this case.</span></span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">==============</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Yes, I think so. At least, I use IDAPro to analysis the binary and I am pretty sure that many function are in the binary but its source line mapping table are not in the dwarf mapping table.</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">If the function does exist in the binary, it is entirely possible (I think) to have no instruction specifically associated with the function definition's source line, even though other instructions are associated with other lines in the function. I (or someone) would need to look at a specific example before being able to say one way or the other if that is what you are running into.<u></u><u></u></span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><u></u>==============</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">I don't understand what "<span style="color:rgb(31,73,125);font-family:Calibri,sans-serif;font-size:14.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">no instruction specifically associated with the function definition's source line,</span>" this sentence mean. Could you please explain more? If you are interested, I am glad to give you a specific example. Please tell me whether you need it.<u></u></span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><br></span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Have you considered building a static array of function addresses? If you used weak references it would not interfere with optimizing away entire functions, which I mentioned above. Or would that be too intrusive into your use case? Apologies if this suggestion has come up before.</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">==============</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">To be honest, No. Since I am using llvm IR to do the code analysis. Function start address is just a part of the whole evaluation. I would prefer to combine all the tools into one tool with llvm IR and dwarf debug information. Thus, I may not evaluate the function addresses with a static table. Thank you very much</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><br></span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Regards</span></p><p class="MsoNormal" style="margin:0px;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Muhui</span></p><br></div><div><br></div><br><div class="gmail_quote"><div><<a href="mailto:paul.robinson@sony.com" target="_blank">paul.robinson@sony.com</a>><wbr>于2018年6月1日 周五下午10:45写道：<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hi Muhui,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Are the functions emitted to the final binary? If a function is not used, there might not be any object code for it in the final binary. Naturally there would
be no entry in the line table in this case.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">If the function does exist in the binary, it is entirely possible (I think) to have no instruction specifically associated with the function definition's source
line, even though other instructions are associated with other lines in the function. I (or someone) would need to look at a specific example before being able to say one way or the other if that is what you are running into.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Have you considered building a static array of function addresses? If you used weak references it would not interfere with optimizing away entire functions,
which I mentioned above. Or would that be too intrusive into your use case? Apologies if this suggestion has come up before.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">--paulr<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><a name="m_573541840383752136_m_6242602782870597869__MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></a></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> llvm-dev [mailto:<a href="mailto:llvm-dev-bounces@lists.llvm.org" target="_blank">llvm-dev-bounces@<wbr>lists.llvm.org</a>]
<b>On Behalf Of </b>Muhui Jiang via llvm-dev<br>
<b>Sent:</b> Friday, June 01, 2018 6:36 AM<br>
<b>To:</b> llvm-dev<br>
<b>Subject:</b> [llvm-dev] Function start address<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Hi<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">I am using LLVM Pass combined with dwarf debug information to get all the function's start address. My steps are below:<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">First, I write the function pass to get the start line of each function, which is finished.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Then, based on the start line of every single function, I try to query the specific line from the dwarf's line binary table, which is generated with llvm-dwarfdump -debug-line. <u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">However, About one third of the whole functions' start line is not found in the mapping table. Thus, I can not get the start binary address. I know that the mapping between source locations and binary addresses is not bijective. I am using
O1 optimization option. I know that some of the information might be lost legitimately because of optimization. But I don't think dwarf will miss so many functions' start addresses. Am I right? Any useful comments and suggestions are welcomed. Many Thanks<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Regards<u></u><u></u></p>
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<p class="MsoNormal">Muhui<u></u><u></u></p>
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