Hi, if this helps, there is a good example of how to do this in a module included with CIL. It catches calls to malloc, calloc and such. The module is in src/ext/sfi.ml
Best regards, Olivier On Fri, May 29, 2009 at 11:10 PM, Mark Hills <mhi...@cs.uiuc.edu> wrote: > Divya, > > I'm not giving too much detail, but hopefully this at least gets you > started. > > The call instruction is a four-tuple, made up of: the (optional) lvalue > assigned into by the call; the expression representing the function > being called; the list of expressions representing the function > arguments; and the location of the call instruction. I'm assuming here > that you are only interested in explicit calls to malloc and other > functions, versus calls through function pointers. This being the case, > the second argument, the expression representing the function being > called, will be something like: > > Lval(Var callee, NoOffset) > > Lval is an expression that contains an lval; the lval itself is made of > of an "lhost", here Var representing a variable, and an offset, which > here is NoOffset since this isn't a field in a structure or an element > of an array. callee is a name I chose, and will be of type varinfo > (function names are also stored in varinfo records). You can check to > see if the call is to malloc by checking callee.vname, which holds the > name of the variable (here, the function being called). > > Zooming out a bit, you may have a match against the call instruction like: > > | Call (lo, Lval (Var callee, NoOffset), al, l) > > If this is a call to malloc, al will just contain 1 element, > representing the size_t value passed to malloc. You may be able to take > the existing expression in the list al, say e (you could even change al > in the match to [e] instead, making this match only calls to functions > that take one argument), and change it to something like: > > BinOp(PlusA,e,Const(4,IInt,None)) > > to, for instance, add 4 to whatever expression is already there . > > There are a number of existing classes that make use of the visitors > available in CIL -- you will probably want to check out one that uses > vinst, which visits instructions, and base your visitor on that. You > could then visit all the instructions and make a change like this to all > calls to malloc (or other functions you are concerned with). > > I hope this helps, and please feel free to contact me with any questions > about the above. > > Best regards, > > Mark > > Divya Krishnan wrote: >> Hi, >> I want to be able to identify certain calls like malloc, realloc etc. >> So I have a visitor that visits all statements and within that the >> instr list and finally identifies Call. However once I identify Call >> statements, how do I identify particular calls like malloc. I tried >> checking to see if CStr in Constant stored some kind of string like >> "malloc". However I see that it does not. So how can I identify malloc >> calls and once identified I would also like modify the call to >> increase the size of the object allocated by the input program. >> >> Thanks, >> -Divya > > ------------------------------------------------------------------------------ > Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT > is a gathering of tech-side developers & brand creativity professionals. Meet > the minds behind Google Creative Lab, Visual Complexity, Processing, & > iPhoneDevCamp as they present alongside digital heavyweights like Barbarian > Group, R/GA, & Big Spaceship. http://p.sf.net/sfu/creativitycat-com > _______________________________________________ > CIL-users mailing list > CIL-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/cil-users > ------------------------------------------------------------------------------ Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers & brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, & iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, & Big Spaceship. http://p.sf.net/sfu/creativitycat-com _______________________________________________ CIL-users mailing list CIL-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/cil-users
