notes

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-C[symspec]	--exec-counts[=symspec]
			Request output in the form of execution counts.
			If "symspec" is present, include only symbols
			selected by "symspec" in the execution count
			listing.  If the option is specified multiple
			times, the execution count listing includes
			symbols selected by the union of all symspecs.

-Z[symspec]	--no-exec-counts[=symspec]
			Suppress output in the execution count listing.
			If given without an argument, the listing is
			suppressed completely.  With a "symspec", suppress
			the selected symbols from the call-graph.  If the
			option is specified multiple times, the union of
			the selected symbols is suppressed.  This option
			has lower precedence than --exec-counts.

-i		--file-info
			Print information about the profile files that
			are read.  The information consists of the
			number and types of records present in the
			profile file.  Currently, a profile file can
			contain any number and any combination of histogram,
			call-graph, or basic-block count records.

-s		--sum

-x		--all-lines
			This option affects annotated source output only.
			By default, only the lines at the beginning of
			a basic-block are annotated.  If this option is
			specified, every line in a basic-block is annotated
			by repeating the annotation for the first line.
			This option is identical to tcov's "-a".

-I dirs		--directory-path=dirs
			This option affects annotated source output only.
			Specifies the list of directories to be searched
			for source files.  The argument "dirs" is a colon
			separated list of directories.  By default, gprof
			searches for source files relative to the current
			working directory only.

-z		--display-unused-functions

-m num		--min-count=num
			This option affects annotated source and execution
			count output only.  Symbols that are executed
			less than "num" times are suppressed.  For annotated
			source output, suppressed symbols are marked
			by five hash-marks (#####).  In an execution count
			output, suppressed symbols do not appear at all.

-L		--print-path
			Normally, source filenames are printed with the path
			component suppressed.  With this option, gprof
			can be forced to print the full pathname of
			source filenames.  The full pathname is determined
			from symbolic debugging information in the image file
			and is relative to the directory in which the compiler
			was invoked.

-y		--separate-files
			This option affects annotated source output only.
			Normally, gprof prints annotated source files
			to standard-output.  If this option is specified,
			annotated source for a file named "path/filename"
			is generated in the file "filename-ann".  That is,
			annotated output is {\em always\/} generated in
			gprof's current working directory.  Care has to
			be taken if a program consists of files that have
			identical filenames, but distinct paths.

-c		--static-call-graph

-t num		--table-length=num
			This option affects annotated source output only.
			After annotating a source file, gprof generates
			an execution count summary consisting of a table
			of lines with the top execution counts.  By
			default, this table is ten entries long.
			This option can be used to change the table length
			or, by specifying an argument value of 0, it can be
			suppressed completely.

-n symspec	--time=symspec
			Only symbols selected by "symspec" are considered
			in total and percentage time computations.
			However, this option does not affect percentage time
			computation for the flat profile.
			If the option is specified multiple times, the union
			of all selected symbols is used in time computations.

-N		--no-time=symspec
			Exclude the symbols selected by "symspec" from
			total and percentage time computations.
			However, this option does not affect percentage time
			computation for the flat profile.
			This option is ignored if any --time options are
			specified.

-w num		--width=num
			Sets the output line width.  Currently, this option
			affects the printing of the call-graph function index
			only.

-e		<no long form---for backwards compatibility only>
-E		<no long form---for backwards compatibility only>
-f		<no long form---for backwards compatibility only>
-F		<no long form---for backwards compatibility only>
-k		<no long form---for backwards compatibility only>
-b		--brief
-dnum		--debug[=num]

-h		--help
			Prints a usage message.

-O name		--file-format=name
			Selects the format of the profile data files.
			Recognized formats are "auto", "bsd", "magic",
			and "prof".  The last one is not yet supported.
			Format "auto" attempts to detect the file format
			automatically (this is the default behavior).
			It attempts to read the profile data files as
			"magic" files and if this fails, falls back to
			the "bsd" format.  "bsd" forces gprof to read
			the data files in the BSD format.  "magic" forces
			gprof to read the data files in the "magic" format.

-T		--traditional
-v		--version

** File Format Changes

The old BSD-derived format used for profile data does not contain a
magic cookie that allows to check whether a data file really is a
gprof file.  Furthermore, it does not provide a version number, thus
rendering changes to the file format almost impossible.  GNU gprof
uses a new file format that provides these features.  For backward
compatibility, GNU gprof continues to support the old BSD-derived
format, but not all features are supported with it.  For example,
basic-block execution counts cannot be accommodated by the old file
format.

The new file format is defined in header file \file{gmon_out.h}.  It
consists of a header containing the magic cookie and a version number,
as well as some spare bytes available for future extensions.  All data
in a profile data file is in the native format of the host on which
the profile was collected.  GNU gprof adapts automatically to the
byte-order in use.

In the new file format, the header is followed by a sequence of
records.  Currently, there are three different record types: histogram
records, call-graph arc records, and basic-block execution count
records.  Each file can contain any number of each record type.  When
reading a file, GNU gprof will ensure records of the same type are
compatible with each other and compute the union of all records.  For
example, for basic-block execution counts, the union is simply the sum
of all execution counts for each basic-block.

*** Histogram Records

Histogram records consist of a header that is followed by an array of
bins.  The header contains the text-segment range that the histogram
spans, the size of the histogram in bytes (unlike in the old BSD
format, this does not include the size of the header), the rate of the
profiling clock, and the physical dimension that the bin counts
represent after being scaled by the profiling clock rate.  The
physical dimension is specified in two parts: a long name of up to 15
characters and a single character abbreviation.  For example, a
histogram representing real-time would specify the long name as
"seconds" and the abbreviation as "s".  This feature is useful for
architectures that support performance monitor hardware (which,
fortunately, is becoming increasingly common).  For example, under DEC
OSF/1, the "uprofile" command can be used to produce a histogram of,
say, instruction cache misses.  In this case, the dimension in the
histogram header could be set to "i-cache misses" and the abbreviation
could be set to "1" (because it is simply a count, not a physical
dimension).  Also, the profiling rate would have to be set to 1 in
this case.

Histogram bins are 16-bit numbers and each bin represent an equal
amount of text-space.  For example, if the text-segment is one
thousand bytes long and if there are ten bins in the histogram, each
bin represents one hundred bytes.


*** Call-Graph Records

Call-graph records have a format that is identical to the one used in
the BSD-derived file format.  It consists of an arc in the call graph
and a count indicating the number of times the arc was traversed
during program execution.  Arcs are specified by a pair of addresses:
the first must be within caller's function and the second must be
within the callee's function.  When performing profiling at the
function level, these addresses can point anywhere within the
respective function.  However, when profiling at the line-level, it is
better if the addresses are as close to the call-site/entry-point as
possible.  This will ensure that the line-level call-graph is able to
identify exactly which line of source code performed calls to a
function.

*** Basic-Block Execution Count Records

Basic-block execution count records consist of a header followed by a
sequence of address/count pairs.  The header simply specifies the
length of the sequence.  In an address/count pair, the address
identifies a basic-block and the count specifies the number of times
that basic-block was executed.  Any address within the basic-address can
be used.

IMPLEMENTATION NOTE: gcc -a can be used to instrument a program to
record basic-block execution counts.  However, the __bb_exit_func()
that is currently present in libgcc2.c does not generate a gmon.out
file in a suiteable format.  This should be fixed for future releases
of gcc.  In the meantime, contact [e-mail] for a version
of __bb_exit_func() to is appropriate.