2009-10-27 Robert Dewar <dewar@adacore.com>

2009-10-27  Robert Dewar  <dewar@adacore.com>

	* s-os_lib.ads, s-os_lib.adb, prj-err.adb, makeutl.adb: Minor
	reformatting.

2009-10-27  Ed Schonberg  <schonberg@adacore.com>

	* sem.util.ads, sem_util.adb (Denotes_Same_Object,
	Denotes_Same_Prefix): New functions to detect overlap between actuals
	that are not by-copy in a call, when one of them is in-out.
	* sem_warn.ads, sem_warn.adb (Warn_On_Overlapping_Actuals): New
	procedure,  called on a subprogram call to warn when an in-out actual
	that is not by-copy overlaps with another actual, thus leadind to
	potentially dangerous aliasing in the body of the called subprogram.
	Currently the warning is under control of the -gnatX switch.
	* sem_res.adb (resolve_call): call Warn_On_Overlapping_Actuals.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@153594 138bc75d-0d04-0410-961f-82ee72b054a4