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atom_application_instrumentation

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NAME

atom_application_instrumentation, AddCallProto, AddCallProgram, AddCallObj, AddCallProc, AddCallBlock, AddCallInst, ReplaceProcedure - Allows an Atom tool's instrumentation routine to add, within an application program, calls to analysis routines  

SYNOPSIS

#include <cmplrs/atom.inst.h>

void AddCallProto( const char * ); void AddCallProgram( PlaceType, const char *, ... ); void AddCallObj( Obj *, PlaceType, const char *, ... ); void AddCallProc( Proc *, PlaceType, const char *, ... ); void AddCallBlock( Block *, PlaceType, const char *, ... ); void AddCallInst( Inst *, PlaceType, const char *, ... ); void ReplaceProcedure( Proc *, const char * );
 

DESCRIPTION

The Atom application instrumentation routines allow you to add arbitrary procedure calls before and after objects, procedures, basic blocks, and instructions. You can also add procedure calls before and after the application program executes.

You can use these routines only from an Atom tool's instrumentation file. See atom(1) for a description of Atom.
 

AddCallProto Routine

You must use the AddCallProto routine to specify the prototype of each procedure call to be added to the program. In other words, an AddCallProto call must define the procedural interface for each call to an analysis procedure to be added to the program by subsequent calls to AddCallProgram, AddCallObj, AddCallProc, AddCallBlock, and AddCallInst.

The format of the prototype is similar to a C language function definition. The name of the analysis procedure is followed by a parenthesized list of arguments.

There are four basic argument types: Constants Computed values (VALUE) Register values (REGV and FREGV) Address translation structure (*XLATE)

Constant types include char, int, long, char *, char[], int[], and long[]. Often, arrays are used to communicate static information, especially large data structures, to analysis procedures. Three special keywords exist to facilitate the passing of array and string arguments: Indicates that the analysis routine cannot modify or write to the passed array or string. Atom allocates the memory for such a string or array in the instrumented program's read-only memory. Using const can thus greatly reduce the memory usage of instrumented programs that have multiple images active simultaneously. Indicates that Atom does not need to make a copy of the data for the string or array during instrumentation. If your instrumentation code passes a stable buffer to AddCallObj, AddCallProc, AddCallBlock, or AddCallInst, it must not modify or free the buffer until after WriteObj is called for the object containing the given Obj, Proc, Block, or Inst. If you pass a stable buffer to AddCallProgram, you must never modify or free the buffer.

Strings returned by the following routines can be considered stable for the duration of the instrumentation process: GetObjName, GetObjOutName, GetAnalName, GetObjInstArray, ProcName, ProcFileName, and GetInstProcCalled. Indicates that Atom does not need to make a copy of the data for the string or array during instrumentation and that it will deallocate the buffer (by calling free) when it is done with it. Instrumentation code should never modify or free such a buffer after it has been passed to AddCallObj, AddCallProc, AddCallBlock, AddCallInst, or AddCallProgram.

You can use the const keyword with either stable or free. The stable and free keywords are mutually exclusive.

The VALUE argument type defines an argument with a 64-bit value that Atom must compute before passing it to the analysis procedure. There are two arguments of the VALUE argument type, as listed in the following table. For such arguments, specify VALUE in the AddCallProto call and the argument's symbolic name in the call to AddCallObj, AddCallProc, AddCallBlock, AddCallInst, or AddCallProgram.


TypeArgumentDescription

VALUEEffAddrValue Effective  load-time address of a load or store instruction. This is the sum of the 64-bit address contained in the base register and the signed 16-bit displacement. (Note that, for a shared library, the run-time PC differs from the compile-time PC.) This argument is valid only on load or store instructions instrumented by an AddCallInst call with InstBefore specified. Otherwise, Atom reports an error.
VALUEBrCondValue Outcome of a conditional branch instruction. Returns a zero (0) if the branch condition will evaluate to false or a 64-bit nonzero value if it will evaluate to true. This argument is valid only on conditional branch instructions instrumented by an AddCallInst call with InstBefore specified. Otherwise, Atom reports an error.

The REGV and FREGV argument types define an argument representing the contents of a register. FREGV is used for floating-point registers; REGV is used for all other registers. There are several arguments of the REGV and FREGV argument types, as listed in the following table. For such arguments, specify REGV or FREGV in the AddCallProto call and the argument's symbolic name in the call to AddCallObj, AddCallProc, AddCallBlock, AddCallInst, or AddCallProgram.


TypeArgumentDescription

REGVREG_n Integer register n, where n is a value from 0 to 31.
REGVREG_RAReturn address register.
REGVREG_GPGlobal pointer.
REGVREG_SPStack pointer.
REGVREG_ZEROInteger register 31.
REGVREG_CCProcessor cycle counter.
REGVREG_PC Pure compile-time (that is, noninstrumented) program counter at the instrumentation point. (Note that, for a shared library, the run-time PC differs from the compile-time PC.)
REGVREG_IPC Instrumented program counter at run-time If the call is from a shared library, the run-time PC is passed.
REGVREG_ARG_n Integer argument register n, where n is a value from 1 to 6.
REGVREG_RETVALInteger function return value.
REGVFREG_n Floating-point register n, where n is a value from 0 to 31.
FREGVFREG_ZEROFloating-point register 31.
FREGVFREG_ARG_n Floating-point argument register n, where n is a value from 1 to 6.
FREGVFREG_RETVALFloating-point function return value.

Note that the special REGV-type value REG_NOTUSED is also defined as a return value from GetInstRegEnum. You cannot pass it as an argument to AddCallObj, AddCallProc, AddCallBlock, AddCallInst, or AddCallProgram.

Note

When you use AddCallObj, you will sometimes find that the analysis routine for each added call requires a slightly different prototype. This usually occurs when you pass an array argument and the number of elements in the array depends on the contents of the object. Normally, it is illegal to reprototype an analysis routine, but Atom makes an exception for array parameters. If the only difference between the new prototype and the old prototype is the length of an array parameter, Atom allows you to use AddCallProto to reprototype the analysis routine. Subsequent calls to that analysis routine will use the new array length.


 

AddCallProgram Routine

Use the AddCallProgram routine in an InstrumentInit or InstrumentAll routine to add a call to an analysis procedure before a program starts execution or after it completes execution. Typically such an analysis procedure does something that applies to the whole program, such as opening an output file or parsing command line options. Supply a PlaceType value of ProgramBefore or ProgramAfter as the instrumentation point, followed by the name of the analysis procedure and a list of its arguments. Since ProgramAfter actions are executed after the program is complete, library routines requiring system services should not be used in ProgramAfter analysis routines.

Because the Instrument routine is called for each object in a program, avoid calling AddCallProgram from the Instrument routine.

If the program forks and ProgramBefore is specified, Atom calls the analysis procedure only once - before the parent process starts execution. If ProgramAfter is specified, Atom calls the analysis procedure after each child process completes execution and after the parent process completes execution.
 

AddCallObj Routine

Use the AddCallObj routine in an instrumentation routine to add a call to an analysis procedure before an object starts execution or after it completes execution. Typically such an analysis procedure does something that applies to the single object, such as initializing some data for its procedures. Supply a PlaceType value of ObjBefore or ObjAfter as the instrumentation point, followed by the name of the analysis procedure and a list of its arguments.

Instrumentation code added at the beginning of an object is executed immediately after the object is loaded into memory (before any procedures in that object are executed). Instrumentation code added at the end of an object is executed immediately before that object is unloaded from memory (after all procedures from that object have finished execution).

Note

An InstrumentAll routine must call the BuildObj routine before calling AddCallObj, AddCallBlock, AddCallProc, or AddCallInst to add analysis routine calls, and before traversing the procedures in the object. BuildObj builds the internal data structures Atom uses to manipulate the object. After the Atom tool traverses and instruments the object, the InstrumentAll routine must call the WriteObj routine to write out the instrumented version of the object. See the atom_object_management(5) reference page for additional information.


 

AddCallProc Routine

Use the AddCallProc routine in an instrumentation routine to add a call to an analysis procedure before a procedure starts execution or after it completes execution. Supply a PlaceType value of ProcBefore or ProcAfter as the instrumentation point, followed by the name of the analysis procedure and a list of its arguments. The following factors determine when the analysis procedures are called: If the procedure has multiple entry points and ProcBefore is specified, Atom calls the analysis procedure at each entry point. If the procedure has multiple exit points and ProcAfter is specified, Atom calls the analysis procedure each time it issues a return. If the procedure does not issue a return (for example, it calls exit or longjmp), Atom does not call the analysis procedure.
 

AddCallBlock Routine

Use the AddCallBlock routine in an instrumentation routine to add a call to an analysis procedure before a basic block starts execution or after it completes execution. Supply a PlaceType value of BlockBefore or BlockAfter as the instrumentation point, followed by the name of the analysis procedure and a list of its arguments.

If the basic block ends with an unconditional branch or jump and BlockAfter is specified, Atom calls the analysis procedure after the basic block completes execution. However, if the basic block ends with a jump to a subroutine that does not return (for instance, the subroutine calls exit or longjmp), Atom does not call the analysis procedure.
 

AddCallInst Routine

Use the AddCallInst routine in an instrumentation routine to add a call to an analysis procedure before a given instruction executes or after it executes. Supply a PlaceType value of InstBefore or InstAfter as the instrumentation point, followed by the name of the analysis procedure and a list of its arguments.

If the instruction is an unconditional branch or jump and InstAfter is specified, Atom calls the analysis procedure after the instruction executes. However, if the instruction is a jump to a subroutine that does not return (for example, the subroutine calls exit or longjmp), Atom does not call the analysis procedure.

An implied scope hierarchy exists in the ordering of calls to analysis procedures before and after the execution of programs, objects, procedures, basic blocks, and instructions. By enforcing a scope hierarchy, Atom guarantees, for instance, that a procedure added at ProgramBefore executes before procedures added in lower scopes. Procedures added at ProgramAfter execute after all application instructions have executed.
 

ReplaceProcedure Routine

Use the ReplaceProcedure routine to replace a procedure call in the instrumented program. For instance, Atom's Third Degree tool uses ReplaceProcedure to replace all calls to dynamic memory allocation routines with special-purpose procedures. It defines the special procedure 3rd_malloc as having the same arguments and return value as the original malloc.
 

EXAMPLES

The following example accumulates wall-clock and per-process time for a procedure. The instrumentation routine defines the prototypes for calls to analysis procedures and identifies the intrumentation points at which those calls take place:


   AddCallProto("Start(REGV)");
   AddCallProto("Stop(REGV)");
   .
   .
   .
   AddCallProc(p,ProcBefore,"Start",REG_CC);
   AddCallProc(p,ProcAfter,"Stop",REG_CC);
   .
   .
   .

The analysis routine is complicated by the format of the cycle counter. The low-order 32 bits contain a free running cycle count. The high-order 32 bits of the counter are an offset that, when added to the low-order 32 bits, produces a cycle count for this process. The low-order 32 bits can be used directly to determine wall clock times:


   long total;
   long process;
   int ccStart;
   int ccStartProcess;


   void Start(unsigned long cc) {
     ccStart = cc;
     ccStartProcess = ((cc << 32) + cc) >> 32;
   }
   void Stop(unsigned long cc) {
     int ccEnd = cc;
     int ccEndProcess = ((cc << 32) + cc) >> 32;
     total += (unsigned) (ccEnd - ccStart);
     process += (unsigned) (ccEndProcess - ccStartProcess);
   }


 

RETURN VALUES

These routines have no return values.
 

FILES

Header file containing external definitions of Atom routines
 

SEE ALSO

Commands: atom(1)

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

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

Programmer's Guide


 

Index

NAME
SYNOPSIS
DESCRIPTION
AddCallProto Routine
AddCallProgram Routine
AddCallObj Routine
AddCallProc Routine
AddCallBlock Routine
AddCallInst Routine
ReplaceProcedure Routine
EXAMPLES
RETURN VALUES
FILES
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:43:11 GMT, October 02, 2010