ada: Improve expansion of conditional expressions in object declarations

This arranges for conditional expressions in objects declarations to have
their expansion delayed when they have a type that cannot be easily copied
or copied at all, including limited and controlled types.

The ultimate goal is to replace the declaration with a renaming declaration
of the dereference of an access value designating an object initialized with
the dependent expression chosen by the condition.

gcc/ada/ChangeLog:

	* einfo.ads (Is_Independent): Document usage on Master_Node objects.
	* exp_aggr.adb (In_Place_Assign_OK): Remove Parent_Kind variable.
	(Convert_To_Assignments): Call Unconditional_Parent and remove the
	restriction on the known size for the in-place expansion of the
	aggregate in the context of an object declaration.
	(Expand_Array_Aggregate): Remove Parent_Kind variable and call
	Unconditional_Parent and Delay_Conditional_Expressions_Between
	* exp_ch3.adb: Remove clauses for Exp_Dbug.
	(Expand_N_Object_Declaration): Factor out the code rewriting the
	declaration as a renaming in Rewrite_Object_Declaration_As_Renaming
	and call the procedure.
	* exp_ch4.adb (Insert_Conditional_Object_Declaration): Declare.
	(Expand_N_Case_Expression): Delay expanding the expression if it is
	in the context of an optimizable object declaration.  If the parent
	node is this object declaration, then replace it with a renaming of
	the dereference of an access value designating an object initialized
	with the dependent expression chosen by the condition.
	(Expand_N_If_Expression): Likewise.
	(Insert_Conditional_Object_Declaration): New procedure.
	* exp_ch6.adb (Expand_Ctrl_Function_Call): Test the unconditional
	parent in the case of an object declaration too.
	* exp_ch7.adb (Build_Finalizer.Process_Declarations): Pass Strict to
	Processing_Actions from the Is_Independent flag on a Master_Node.
	* exp_util.ads (Rewrite_Object_Declaration_As_Renaming): Declare.
	* exp_util.adb: Add clauses for Exp_Dbug.
	(Rewrite_Object_Declaration_As_Renaming): New procedure extracted
	from Expand_N_Object_Declaration.
	* sem_ch3.adb (Analyze_Object_Declaration): Also leave the analysis
	if the declaration has been replaced with a renaming in the case of
	an initialization expression that is a conditional expression.

1 files changed, 1 insertions, 30 deletions

diff --git a/gcc/ada/exp_ch3.adb b/gcc/ada/exp_ch3.adb
index 2a0b0e6..afcb0a9 100644
--- a/gcc/ada/exp_ch3.adb
+++ b/gcc/ada/exp_ch3.adb
@@ -38,7 +38,6 @@ with Exp_Ch4;        use Exp_Ch4;
 with Exp_Ch6;        use Exp_Ch6;
 with Exp_Ch7;        use Exp_Ch7;
 with Exp_Ch9;        use Exp_Ch9;
-with Exp_Dbug;       use Exp_Dbug;
 with Exp_Disp;       use Exp_Disp;
 with Exp_Dist;       use Exp_Dist;
 with Exp_Put_Image;
@@ -9134,35 +9133,7 @@ package body Exp_Ch3 is
       --  illegal code if written by hand, but that's OK.
 
       if Rewrite_As_Renaming then
-         Rewrite (N,
-           Make_Object_Renaming_Declaration (Loc,
-             Defining_Identifier => Def_Id,
-             Subtype_Mark        => New_Occurrence_Of (Etype (Def_Id), Loc),
-             Name                => Expr_Q));
-
-         --  Keep original aspects
-
-         Move_Aspects (Original_Node (N), N);
-
-         --  We do not analyze this renaming declaration, because all its
-         --  components have already been analyzed, and if we were to go
-         --  ahead and analyze it, we would in effect be trying to generate
-         --  another declaration of X, which won't do.
-
-         Set_Renamed_Object (Def_Id, Expr_Q);
-         Set_Analyzed (N);
-
-         --  We do need to deal with debug issues for this renaming
-
-         --  First, if entity comes from source, then mark it as needing
-         --  debug information, even though it is defined by a generated
-         --  renaming that does not come from source.
-
-         Set_Debug_Info_Defining_Id (N);
-
-         --  Now call the routine to generate debug info for the renaming
-
-         Insert_Action (N, Debug_Renaming_Declaration (N));
+         Rewrite_Object_Declaration_As_Renaming (N, Expr_Q);
       end if;
 
    --  Exception on library entity not available