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atom_application_instrumentation(5)
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:
const
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.
stable
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.
free
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.
____________________________________________________________________
Type Argument Description
____________________________________________________________________
VALUE EffAddrValue
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.
VALUE BrCondValue
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.
___________________________________________________________________
Type Argument Description
___________________________________________________________________
REGV REG_n
Integer register n, where n is a value from 0
to 31.
REGV REG_RA Return address register.
REGV REG_GP Global pointer.
REGV REG_SP Stack pointer.
REGV REG_ZERO Integer register 31.
REGV REG_CC Processor cycle counter.
REGV REG_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.)
REGV REG_IPC
Instrumented program counter at run-time If
the call is from a shared library, the run-
time PC is passed.
REGV REG_ARG_n
Integer argument register n, where n is a
value from 1 to 6.
REGV REG_RETVAL Integer function return value.
REGV FREG_n
Floating-point register n, where n is a value
from 0 to 31.
FREGV FREG_ZERO Floating-point register 31.
FREGV FREG_ARG_n
Floating-point argument register n, where n
is a value from 1 to 6.
FREGV FREG_RETVAL Floating-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 contains interprocedural branches or interprocedural
jumps, the call to the analysis procedure will occur before the branch
or jump. Compilers can optimize return statements or non-returning
function calls to interprocedural branches. To avoid this, recompile
with -O0 or -no_inline.
· 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
/usr/include/cmplrs/atom.inst.h
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
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Index for
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