2007-04-20  Robert Dewar  <dewar@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>

	* g-comlin.ads, g-comlin.adb: 
	Add new warning for renaming of function return objects

	* opt.adb (Tree_Write, Tree_Read): Use proper expressions for size
	(Tree_Read): Use size of object instead of type'object_size, since the
	latter is incorrect for packed array types.
	(Tree_Write): Same fix

	* opt.ads: Add new warning for renaming of function return objects
	(Generating_Code): New boolean variable used to indicate that the
	frontend as finished its work and has called the backend to process
	the tree and generate the object file.
	(GCC_Version): Is now private
	(Static_Dispatch_Tables): New constant declaration.
	(Overflow_Checks_Unsuppressed): New flag.
	(Process_Suppress_Unsuppress): Set Overflow_Checks_Unsuppressed.
	(List_Closure): New flag for gnatbind (-R)
	Zero_Formatting: New flag for gnatbind (-Z)
	(Special_Exception_Package_Used): New flag.
	(Warn_On_Unrepped_Components): New flag.

	* sem_ch8.adb (Check_Library_Unit_Renaming): Check that the renamed
	unit is a compilation unit, rather than relying on its scope, so that
	Standard can be renamed.
	(Analyze_Object_Renaming): Add new warning for renaming of function
	return objects.
	Also reject attempt to rename function return object in Ada 83 mode.
	(Attribute_Renaming): In case of tagged types, add the body of the
	generated function to the freezing actions of the type.
	(Find_Type): A protected type is visible right after the reserved word
	"is" is encountered in its type declaration. Set the entity and type
	rather than emitting an error message.
	(New_Scope): Properly propagate Discard_Names to inner scopes
	(Check_Nested_Access): New procedure.
	(Has_Nested_Access, Set_Has_Nested_Access): New procedures.
	(Find_Direct_Name, Note_Possible_Modification): Use Check_Nested_Access.

	* sem_warn.ads, sem_warn.adb: Improvements to infinite loop warning
	Add new warning for renaming of function return objects
	(Check_References): Suppress warnings for objects whose type or
	base type has Warnings suppressed.
	(Set_Dot_Warning_Switch): Add processing for -gnatw.c/C
	(Set_Warning_Switch): Include new -gnatwc in -gnatwa

From-SVN: r125414