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<div class="moz-cite-prefix">On 3/10/13 11:17 PM, Jane wrote:<br>
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<div>Hi,</div>
<div> I'm trying to write a pass to detect all free()/delete()
call instructions in LLVM IR.<span style="line-height: 1.5;">The
method is as follows.</span></div>
<div> First I find Call Instructions: <u>CallInst
*CI=dyn_cast<CallInst>(&*i);</u></div>
<div> then see if the Function name matches:</div>
<div> <u>name=CI->getCalledFunction()->getName();
if(name=="_ZdlPv"||name=="_ZdaPv"||name=="free")</u></div>
<div> It worked but when <span style="line-height: 1.5;"> </span><span
style="line-height: 1.5;">something like this occurs</span></div>
<div> <u> %call2 = call i32 bitcast (i32 (...)* @free to i32
(i8*)*)(i8* %call1) nounwind, !dbg !16</u></div>
<div> It seems like a indirect function call and I don't know
how to detect free() in such situation.</div>
<div> By the way, is there any way that is more convenient to <span
style="line-height: 1.5;">detect all free()/delete() call
instructions in a module except by matching the function name?</span></div>
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<br>
As others have mentioned, to handle situations in which the function
pointer is casted before the call, fetch the called SSA value using
Function::getCalledValue() and then use the stripPointerCasts()
method to remove all the casts.<br>
<br>
However, that only solves the problem of calls to free() that cast
the free() function pointer. It is also possible that an indirect
function call calls free() as well. To find those, you'll need to
use the CallGraph interface or, better yet, the DSCallGraph
interface from DSA (which is located in the poolalloc project).<br>
<br>
-- John T.<br>
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