<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
code
{mso-style-priority:99;
font-family:"Courier New";}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0cm;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.apple-converted-space
{mso-style-name:apple-converted-space;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Courier New";
mso-fareast-language:EN-GB;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-GB" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Dear All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p style="margin:0cm;margin-bottom:.0001pt;line-height:13.35pt;background:white;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black">I am new to LLVM and using it create a simple pass for array bounds checking.</span>
<o:p></o:p></p>
<p style="margin:0cm;margin-bottom:.0001pt;line-height:13.35pt;background:white;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black">How can i retrieve pointer to a memory area that is accessed by a function call . I have written a Pass that can intercept function calls and detect whether it is writing to a memory
on not using </span><span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE">Instruction::mayWriteToMemory()</span><span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black">.
Whether a function accessing memory or not can be checked by </span><span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE">Instruction::mayReadFromMemory()</span><span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black"> and </span><span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE">Instruction::mayWriteToMemory()</span><span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black"> but
how can i get staring address of those memory areas (program variables) that are being written by.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt;line-height:13.35pt;background:white;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt;line-height:13.35pt;background:white;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-GB">For example, for the c code<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">int main(){<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">char arrd[]="This is destination ";<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">char arrs[]="COPIED STRING";<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">strcpy(arrd, arrs);<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">printf("Final copied string : %s\n", arrd);<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">return 0;<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:13.35pt;background:#EEEEEE;vertical-align:baseline">
<span style="font-size:10.5pt;font-family:Consolas;color:black;border:none windowtext 1.0pt;padding:0cm;background:#EEEEEE;mso-fareast-language:EN-GB">}</span><span style="font-size:10.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">Does LLVM at IR level provide such functionality to intercept call to “strcpy” and provide starting and end address of any data variables being written by it?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ahmed Saeed,<o:p></o:p></p>
<p class="MsoNormal">Research Student,<o:p></o:p></p>
<p class="MsoNormal">Glasgow Caledonian University, UK.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<br>
<font face="Arial" color="Gray" size="2">Glasgow Caledonian University is a registered Scottish charity, number SC021474<br>
</font>
</body>
</html>