This patch adds functionality to libgcov to enable user applications to
collect profile data only in regions of interest. This is useful, for
example, to collect profile data from a long-running server only
during the time when it is serving requests.

Specifically, the new routines __gcov_reset will clear all profile counters
to zero and __gcov_dump will write out the profile information collected so
far. A global variable is used to prevent writing out the profile a
second time during exit.

2012-05-08   Teresa Johnson  <tejohnson@google.com>

	* libgcc/libgcov.c (gcov_clear, __gcov_reset): New functions.
	(__gcov_dump): Ditto.
	(gcov_dump_complete): New global variable.
	(gcov_exit): Export hidden to enable use in L_gcov_dump.
	(__gcov_flush): Outline functionality now in gcov_clear.
	* libgcc/Makefile.in (L_gcov_reset, L_gcov_dump): Define.
	* gcc/gcov-io.h (__gcov_reset, __gcov_dump): Declare.
	* gcc/doc/gcov.texi: Add note on using __gcov_reset and __gcov_dump.

From-SVN: r187297