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atom instrumentation_routines, Instrument, InstrumentAll, InstrumentInit, InstrumentFini - Atom tool instrumentation routines  


#include <cmplrs/atom.inst.h>

void Instrument( int iargc, char **iargv, Obj *obj ); void InstrumentInit( int iargc, char **iargv ); void InstrumentFini( void ); unsigned InstrumentAll( int iargc, char **iargv );


Atom invokes a tool's instrumentation routine on a given application program when that program is specified as the application_program parameter to the atom command, and either of the following is true: The tool is a prepackaged tool specified as an argument to the -tool flag of an atom command. By default, Atom looks for prepackaged tools in the /usr/lib/cmplrs/atom/tools and /usr/lib/cmplrs/atom/examples directories. The file containing the instrumentation routine is specified as the instrum_file parameter of an atom command.

The instrumentation routine contains the code that traverses the objects, procedures, basic blocks, and instructions to locate instrumentation points; adds calls to analysis procedures; and builds the instrumented version of an application.

An instrumentation routine can employ one of the following interfaces based on the needs of the tool: Atom calls the Instrument routine for each eligible object in the application program. As a result, an Instrument routine should not call AddCallProgram and does not need to use the object navigation routines (GetFirstObj, GetLastObj, GetNextObj, and GetPrevObj). Because Atom automatically writes each object before passing the next to the Instrument routine, the Instrument routine should never call the BuildObj, WriteObj, or ReleaseObj routines.

If an Instrument routine calls the ResolveTargetProc or ResolveNamedProc routine for a procedure name that exists in another object, the routine sets the proc field in the ProcRes structure to NULL. If the tool uses ResolveNamedProc to add special instrumentation code to a specific procedure, it can use a construct like the following:
Instrument(int iargc, char **iargv, Obj *obj) {
    ProcRes     pres;

    ResolveNamedProc("malloc", &pres);
    if (pres.proc != NULL) {
         AddCallProc(pres.proc, ProcBefore, "foo");

         <Add special instrumentation code>
    } }

Because malloc exists in only one of the objects, this construct adds the special instrumentation code to malloc exactly once - when its object is instrumented.
When using the Instrument interface, you can define an InstrumentInit routine to perform tasks required before Atom calls Instrument for the first object (such as defining analysis routine prototypes, adding program level instrumentation calls, and performing global initializations). Atom passes the arguments specified in the -toolargs flag to the atom command to the InstrumentInit routine. You can also define an InstrumentFini routine to perform tasks required after Atom calls Instrument for the last object (such as global cleanup). Atom passes no parameters to the InstrumentFini routine.
Atom restricts an InstrumentInit or InstrumentFini routine to using only a subset of the Atom routines. In general terms, either routine is allowed to add prototypes, add program level analysis calls, traverse objects, and perform some queries about objects. Neither can traverse the procedures in any object.
Specifically, InstrumentInit and InstrumentFini can call only the following routines: AddCallProto GetFirstObj GetLastObj GetNextObj GetPrevObj Calls to GetObjInfo that do not specify an ObjInfoType of ObjNumberProcs, ObjNumberBlocks, or ObjNumberInsts GetObjName GetObjOutName GetAnalName GetObjInstArray GetObjInstCount GetProgInfo
Additionally, an InstrumentInit routine can call AddCallProgram. Normally a tool does not use any Atom routines in an InstrumentFini routine. Atom calls the InstrumentAll routine once for the entire application program, thus allowing a tool's instrumentation code itself to determine how to traverse the application's objects. With this method, you do not specify InstrumentInit or InstrumentFini routines. The InstrumentAll routine does everything. Because of this, an InstrumentAll routine must call the Atom object navigation routines itself and use the BuildObj, WriteObj, or ReleaseObj routine to manage the application's objects.
A typical InstrumentAll routine might contain the following code:
unsigned InstrumentAll(int iargc, char **iargv) {
    Obj *       obj;

    AddCallProto("foo(int, REGV)");

    AddCallProgram(ProgramBefore, "Startup");
    AddCallProgram(ProgramAfter, "Finish");

    for (obj = GetFirstObj();  obj;  obj = GetNextObj(obj))
        if (BuildObj(obj))

        /* instrument obj */

    } }

The InstrumentAll routine first adds the prototypes for the analysis routine and then adds the program-level analysis calls. Next, it traverses the objects in the program, calling BuildObj to build the internal Atom data structures for each object before traversing that object's procedures or adding analysis calls to the object. Afterwards, it calls WriteObj to write out the instrumented version of the given object and deallocate the internal data structures that BuildObj created. Note that, because BuildObj may return an error code, the InstrumentAll routine propagates this error return back to Atom by returning 1. An InstrumentAll routine must return zero (0) to Atom if the tool completes successfully, or 1 if it encounters an error. Atom terminates with an error code if the routine returns 1.

Regardless of the instrumentation routine interface, Atom passes the arguments specified in the -toolargs flag to the routine. In the case of the Instrument interface, Atom also passes a pointer to the current object.

An Atom tool should use one of the following methods of specifying analysis routines to instrument an entire object or application program: If an analysis routine applies to something contained within a single object, use AddCallObj. An example of this is an analysis routine that initializes some data for a procedure. If an analysis routine applies to the entire program, call AddCallProgram from an InstrumentInit routine (when using the Instrument interface) or from the InstrumentAll routine. An example of this is an analysis routine that opens an output file or parses command line options.


These routines return values as described in the preceding section.


Header file containing external definitions of Atom routines


Commands: atom(1)

AtomTools: hiprof(5), pixie(5), third(5)

Functions: atom_application_instrumentation(5), atom_application_query(5), atom_application_navigation(5), atom_description_file(5), atom_application_resolvers(5), atom_object_management(5), AnalHeapBase(5), Xlate(5)

Programmer's Guide




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Time: 02:43:08 GMT, October 02, 2010