On Wednesday 20 February 2008 09:26, you wrote: > In fact, i think i've explained my problem in a very silly way (and i'm > sorry for that ...). > Let's suppose we're given a input IRSB with a t3 = Add32(t2,t5) statement. > What i intend to do is to access, at run-time, the value of t3. > My first idea was to use a helper c function which would, at run time, > access the temporaries (via pointers f.e.). But how to access this > temporaries at run time, via pointers ?
You can't access them via pointers. The temporaries are stored in registers by a later stage of the compilation (JIT) pipeline. Your instrumentation function will scan the input IRSB. It must copy all the input code into a new IRSB (else the program won't work properly). But when it does the copy, it can add new code of its own. For example, if it sees t3 = Add32(t2,t5) then after that you can create an IRStmt which contains an IRExpr_RdTmp(t3). For example, you could create an IRStmt which calls a C helper function, passing it the value of t3. Many tools do that kind of thing. Try studying lackey, it is relatively simple. Try to understand the output of --trace-flags=10001000. It is better to generate in-inline IR instrumentation than to generate many calls to C helper functions, since calling C helpers a lot will make your programs run slowly. J ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Valgrind-developers mailing list Valgrind-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-developers
