2007-04-20  Thomas Quinot  <quinot@adacore.com>
	    Olivier Hainque  <hainque@adacore.com>
	    Robert Dewar  <dewar@adacore.com>

	* a-except.ads, a-except.adb: (Rmsg_28): Fix description for E.4(18)
	check.
	(Raise_Current_Excep): Call Debug_Raise_Exception just before
	propagation starts, to let debuggers know about the event in a reliable
	fashion.
	(Local_Raise): Moved to System.Exceptions
	More convenient to have this as a separate unit

	* s-except.adb, s-except.ads: New files.

	* a-exextr.adb (Unhandled_Exception): Delete - replaced by
	Debug_Unhandled_Exception in System.Exceptions where it belongs
	together with a couple of other debug helpers.
	(Notify_Unhandled_Exception): Use Debug_Unhandled_Exception instead of
	the former Unhandled_Exception.

	* exp_ch11.ads, exp_ch11.adb: (Possible_Local_Raise): New procedure
	(Warn_No_Exception_Propagation): New procedure
	(Warn_If_No_Propagation): Rewritten for new warning generation
	(Expand_Exception_Handlers): New warning generation
	(Expand_N_Raise_xxx_Error): Rewritten for new warnings
	(Add_Exception_Label): Use Special_Exception_Package_Used for test
	instead of Most_Recent_Exception_Used (accomodates Exception_Traces)
	(Expand_Local_Exception_Handlers): Unconditionally add extra block wrap
	even if restriction is set (makes life easier in Check_Returns)
	(Expand_Local_Exception_Handlers): Follow renamed entity chain when
	checking exception identities.
	(Expand_Local_Exception_Handlers): Do not optimize when all others case
	(Expand_Local_Exception_Handlers): Set Exception_Junk flag on generated
	block for handler (used by Check_Returns)
	(Expand_Local_Exception_Handlers): Local_Raise now takes an address
	(Expand_N_Handled_Sequence_Of_Statements): Properly handle -gnatd.x to
	remove all exception handlers when optimizing local raise statements.
	(Find_Local_Handler): Use Get_Renamed_Entity
	(Expand_N_Handled_Sequence_Of_Statements): If the handled sequence is
	marked analyzed after expanding exception handlers, do not generate
	redundant cleanup actions, because they have been constructed already.

From-SVN: r125375