<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
On 5/3/11 4:08 PM, tarun agrawal wrote:
<blockquote
cite="mid:BANLkTikdgWRykEQEEk6QDHChbzRNdu8D1A@mail.gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=ISO-8859-1">
HI <br>
<br>
I know it is a very simple question not worth asking here but I am
really struggling pls help me out..<br>
</blockquote>
<br>
This is a question worth asking; it's just that not everyone can
answer all the time.<br>
:)<br>
<br>
If all you want to do is to follow the SSA def-use chain within a
single function, then this is very easy. All you have to do is use
the use_iterator of the Instruction object to iterate through its
def-use chain. For all uses that are instructions, use the
getParent() method to find the basic block containing the
instruction. That's it.<br>
<br>
This approach won't work in two cases:<br>
<br>
1) If you want to trace def/use through memory. Memory is not in
SSA form, and so you have to use extra analysis to track from which
store the result of a load originates.<br>
<br>
2) If you want to track def/use inter-procedurally through function
arguments and return values. If you don't care about tracking
through memory, this is a fairly easy inter-procedural analysis to
do, and we have some code internally at University of Illinois that
does it. If you need it, I can talk to Vikram and see if we can
give you a copy.<br>
<br>
For more information on how to iterate through def-use chains, see
the LLVM Programmer's Manual:<br>
<a class="moz-txt-link-freetext" href="http://llvm.org/docs/ProgrammersManual.html#iterate_chains">http://llvm.org/docs/ProgrammersManual.html#iterate_chains</a><br>
<br>
-- John T.<br>
<br>
<blockquote
cite="mid:BANLkTikdgWRykEQEEk6QDHChbzRNdu8D1A@mail.gmail.com"
type="cite"><br>
<div class="gmail_quote">On Tue, May 3, 2011 at 10:10 PM, tarun
agrawal <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:tarun@cse.iitb.ac.in">tarun@cse.iitb.ac.in</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">Hi,<br>
<br>
I need to get all the basic blocks that are there, in the path
from definition of an instruction to use of that instruction.<br>
<br>
<br>
Regards <br>
<font color="#888888">Tarun<br>
</font></blockquote>
</div>
<br>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
LLVM Developers mailing list
<a class="moz-txt-link-abbreviated" href="mailto:LLVMdev@cs.uiuc.edu">LLVMdev@cs.uiuc.edu</a> <a class="moz-txt-link-freetext" href="http://llvm.cs.uiuc.edu">http://llvm.cs.uiuc.edu</a>
<a class="moz-txt-link-freetext" href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</a>
</pre>
</blockquote>
<br>
</body>
</html>