Comments
Patch
===================================================================
@@ -4327,10 +4327,47 @@
Last_Object : Node_Id;
Related_Node : Node_Id)
is
- Requires_Hooking : constant Boolean :=
- Nkind_In (N, N_Function_Call,
- N_Procedure_Call_Statement);
+ function Requires_Hooking return Boolean;
+ -- Determine whether the context requires transient variable export
+ -- to the outer finalizer. This scenario arises when the context may
+ -- raise an exception.
+ ----------------------
+ -- Requires_Hooking --
+ ----------------------
+
+ function Requires_Hooking return Boolean is
+ function Is_Subprogram_Call (Nod : Node_Id) return Boolean;
+ -- Determine whether a particular node is a procedure of function
+ -- call.
+
+ ------------------------
+ -- Is_Subprogram_Call --
+ ------------------------
+
+ function Is_Subprogram_Call (Nod : Node_Id) return Boolean is
+ begin
+ return
+ Nkind_In (Nod, N_Function_Call, N_Procedure_Call_Statement);
+ end Is_Subprogram_Call;
+
+ -- Start of processing for Requires_Hooking
+
+ begin
+ -- The context is either a procedure or function call or an object
+ -- declaration initialized by such a call. In all these cases, the
+ -- calls are assumed to raise an exception.
+
+ return
+ Is_Subprogram_Call (N)
+ or else
+ (Nkind (N) = N_Object_Declaration
+ and then Is_Subprogram_Call (Expression (N)));
+ end Requires_Hooking;
+
+ -- Local variables
+
+ Must_Hook : constant Boolean := Requires_Hooking;
Built : Boolean := False;
Desig_Typ : Entity_Id;
Fin_Block : Node_Id;
@@ -4395,7 +4432,7 @@
-- enclosing sequence of statements where their corresponding
-- "hooks" are picked up by the finalization machinery.
- if Requires_Hooking then
+ if Must_Hook then
declare
Expr : Node_Id;
Ptr_Id : Entity_Id;
@@ -4470,7 +4507,7 @@
-- Generate:
-- Temp := null;
- if Requires_Hooking then
+ if Must_Hook then
Append_To (Stmts,
Make_Assignment_Statement (Loc,
Name => New_Reference_To (Temp_Id, Loc),
This patch adds code to recognize a scenario where an object is initialized by a sequence of nested function calls where one of them returns a controlled result. This in turn triggers the mechanism which exports such transient objects to the enclosing finalizer on the assumption that one of the calls may raise an exception. ------------ -- Source -- ------------ -- types.ads with Ada.Finalization; use Ada.Finalization; package Types is type Ctrl is new Controlled with null record; procedure Finalize (Obj : in out Ctrl); end Types; -- types.adb with Ada.Text_IO; use Ada.Text_IO; package body Types is procedure Finalize (Obj : in out Ctrl) is begin Put_Line ("Finalize"); end Finalize; end Types; -- main.adb with Ada.Text_IO; use Ada.Text_IO; with Types; use Types; procedure Main is function Return_Self (Obj : Ctrl) return Ctrl is begin return Obj; end Return_Self; function Blow_Up (Obj : Ctrl) return Boolean is begin raise Constraint_Error; return True; end Blow_Up; Obj : Ctrl; begin Put_Line ("Main"); declare Flag : constant Boolean := Blow_Up (Return_Self (Obj)); begin null; end; Put_Line ("End"); end Main; ---------------------------- -- Compilation and output -- ---------------------------- $ gnatmake -q -gnat05 main.adb $ ./main $ Main $ Finalize $ Finalize $ $ raised CONSTRAINT_ERROR : main.adb:12 explicit raise Tested on x86_64-pc-linux-gnu, committed on trunk 2012-06-12 Hristian Kirtchev <kirtchev@adacore.com> * exp_ch7.adb (Process_Transient_Objects): Renamed constant Requires_Hooking to Must_Hook and replace all occurrences of the name. (Requires_Hooking): New routine. Detect all contexts that require transient variable export to the outer finalizer due to a potential exception.