@@ -364,20 +364,39 @@ package body Exp_Ch7 is
procedure Check_Unnesting_Elaboration_Code (N : Node_Id);
-- The statement part of a package body that is a compilation unit may
- -- contain blocks that declare local subprograms. In Subprogram_Unnesting
+ -- contain blocks that declare local subprograms. In Subprogram_Unnesting_
-- Mode such subprograms must be handled as nested inside the (implicit)
-- elaboration procedure that executes that statement part. To handle
-- properly uplevel references we construct that subprogram explicitly,
-- to contain blocks and inner subprograms, The statement part becomes
-- a call to this subprogram. This is only done if blocks are present
- -- in the statement list of the body.
-
- procedure Check_Unnesting_In_Declarations (Decls : List_Id);
- -- Similarly, the declarations in the package body may have created
- -- blocks with nested subprograms. Such a block must be transformed into a
- -- procedure followed by a call to it, so that unnesting can handle uplevel
- -- references within these nested subprograms (typically generated
- -- subprograms to handle finalization actions).
+ -- in the statement list of the body. (It would be nice to unify this
+ -- procedure with Check_Unnesting_In_Decls_Or_Stmts, if possible, since
+ -- they're doing very similar work, but are structured differently. ???)
+
+ procedure Check_Unnesting_In_Decls_Or_Stmts (Decls_Or_Stmts : List_Id);
+ -- Similarly, the declarations or statements in library-level packages may
+ -- have created blocks blocks with nested subprograms. Such a block must be
+ -- transformed into a procedure followed by a call to it, so that unnesting
+ -- can handle uplevel references within these nested subprograms (typically
+ -- subprograms that handle finalization actions). This also applies to
+ -- nested packages, including instantiations, in which case it must
+ -- recursively process inner bodies.
+
+ procedure Check_Unnesting_In_Handlers (N : Node_Id);
+ -- Similarly, check for blocks with nested subprograms occurring within
+ -- a set of exception handlers associated with a package body N.
+
+ procedure Unnest_Block (Decl : Node_Id);
+ -- Blocks that contain nested subprograms with up-level references need to
+ -- create activation records for them. We do this by rewriting the block as
+ -- a procedure, followed by a call to it in the same declarative list, to
+ -- replicate the semantics of the original block.
+ --
+ -- A common source for such block is a transient block created for a
+ -- construct (declaration, assignment, etc.) that involves controlled
+ -- actions or secondary-stack management, in which case the nested
+ -- subprogram is a finalizer.
procedure Check_Visibly_Controlled
(Prim : Final_Primitives;
@@ -4020,27 +4039,39 @@ package body Exp_Ch7 is
--------------------------------------
procedure Check_Unnesting_Elaboration_Code (N : Node_Id) is
- Loc : constant Source_Ptr := Sloc (N);
- First_Ent : Entity_Id := Empty;
- Loop_Id : Entity_Id := Empty;
-
- function First_Local_Scope (L : List_Id) return Entity_Id;
- -- Find first entity in the elaboration code of the body that contains
- -- or represents a subprogram body. A body can appear within a block or
- -- a loop or can appear by itself if generated for an object declaration
- -- that involves controlled actions. The first such entity encountered
- -- is used to reset the scopes of all entities that become local to the
- -- new elaboration procedure. This is needed for subsequent unnesting,
- -- which depends on the scope links to determine the nesting level of
- -- each subprogram.
+ Loc : constant Source_Ptr := Sloc (N);
+ Block_Elab_Proc : Entity_Id := Empty;
+
+ procedure Set_Block_Elab_Proc;
+ -- Create a defining identifier for a procedure that will replace
+ -- a block with nested subprograms (unless it has already been created,
+ -- in which case this is a no-op).
+
+ procedure Set_Block_Elab_Proc is
+ begin
+ if No (Block_Elab_Proc) then
+ Block_Elab_Proc :=
+ Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('I'));
+ end if;
+ end Set_Block_Elab_Proc;
+
+ procedure Reset_Scopes_To_Block_Elab_Proc (L : List_Id);
+ -- Find entities in the elaboration code of a library package body that
+ -- contain or represent a subprogram body. A body can appear within a
+ -- block or a loop or can appear by itself if generated for an object
+ -- declaration that involves controlled actions. The first such entity
+ -- forces creation of a new procedure entity (via Set_Block_Elab_Proc)
+ -- that will be used to reset the scopes of all entities that become
+ -- local to the new elaboration procedure. This is needed for subsequent
+ -- unnesting actions, which depend on proper setting of the Scope links
+ -- to determine the nesting level of each subprogram.
-----------------------
-- Find_Local_Scope --
-----------------------
- function First_Local_Scope (L : List_Id) return Entity_Id is
+ procedure Reset_Scopes_To_Block_Elab_Proc (L : List_Id) is
Id : Entity_Id;
- Scop : Entity_Id;
Stat : Node_Id;
begin
@@ -4050,41 +4081,36 @@ package body Exp_Ch7 is
when N_Block_Statement =>
Id := Entity (Identifier (Stat));
- if No (First_Ent) then
- First_Ent := Id;
- end if;
+ -- The Scope of this block needs to be reset to the new
+ -- procedure if the block contains nested subprograms.
if Present (Id) and then Contains_Subprogram (Id) then
- return Id;
+ Set_Block_Elab_Proc;
+ Set_Scope (Id, Block_Elab_Proc);
end if;
when N_Loop_Statement =>
Id := Entity (Identifier (Stat));
- if No (First_Ent) then
- First_Ent := Id;
- end if;
-
- if Contains_Subprogram (Id) then
+ if Present (Id) and then Contains_Subprogram (Id) then
if Scope (Id) = Current_Scope then
- Loop_Id := Id;
+ Set_Block_Elab_Proc;
+ Set_Scope (Id, Block_Elab_Proc);
end if;
-
- return Id;
end if;
- when N_If_Statement =>
- Scop := First_Local_Scope (Then_Statements (Stat));
+ -- We traverse the loop's statements as well, which may
+ -- include other block (etc.) statements that need to have
+ -- their Scope set to Block_Elab_Proc. (Is this really the
+ -- case, or do such nested blocks refer to the loop scope
+ -- rather than the loop's enclosing scope???.)
- if Present (Scop) then
- return Scop;
- end if;
+ Reset_Scopes_To_Block_Elab_Proc (Statements (Stat));
- Scop := First_Local_Scope (Else_Statements (Stat));
+ when N_If_Statement =>
+ Reset_Scopes_To_Block_Elab_Proc (Then_Statements (Stat));
- if Present (Scop) then
- return Scop;
- end if;
+ Reset_Scopes_To_Block_Elab_Proc (Else_Statements (Stat));
declare
Elif : Node_Id;
@@ -4092,11 +4118,8 @@ package body Exp_Ch7 is
begin
Elif := First (Elsif_Parts (Stat));
while Present (Elif) loop
- Scop := First_Local_Scope (Statements (Elif));
-
- if Present (Scop) then
- return Scop;
- end if;
+ Reset_Scopes_To_Block_Elab_Proc
+ (Then_Statements (Elif));
Next (Elif);
end loop;
@@ -4109,24 +4132,19 @@ package body Exp_Ch7 is
begin
Alt := First (Alternatives (Stat));
while Present (Alt) loop
- Scop := First_Local_Scope (Statements (Alt));
-
- if Present (Scop) then
- return Scop;
- end if;
+ Reset_Scopes_To_Block_Elab_Proc (Statements (Alt));
Next (Alt);
end loop;
end;
+ -- Reset the Scope of a subprogram occurring at the top level
+
when N_Subprogram_Body =>
Id := Defining_Entity (Stat);
- if No (First_Ent) then
- First_Ent := Id;
- end if;
-
- return Id;
+ Set_Block_Elab_Proc;
+ Set_Scope (Id, Block_Elab_Proc);
when others =>
null;
@@ -4134,67 +4152,52 @@ package body Exp_Ch7 is
Next (Stat);
end loop;
-
- return Empty;
- end First_Local_Scope;
+ end Reset_Scopes_To_Block_Elab_Proc;
-- Local variables
H_Seq : constant Node_Id := Handled_Statement_Sequence (N);
Elab_Body : Node_Id;
Elab_Call : Node_Id;
- Elab_Proc : Entity_Id;
- Ent : Entity_Id;
-- Start of processing for Check_Unnesting_Elaboration_Code
begin
- if Unnest_Subprogram_Mode
- and then Present (H_Seq)
- and then Is_Compilation_Unit (Current_Scope)
- then
- Ent := First_Local_Scope (Statements (H_Seq));
+ if Present (H_Seq) then
+ Reset_Scopes_To_Block_Elab_Proc (Statements (H_Seq));
- -- There msy be subprograms declared in the exception handlers
+ -- There may be subprograms declared in the exception handlers
-- of the current body.
- if No (Ent) and then Present (Exception_Handlers (H_Seq)) then
+ if Present (Exception_Handlers (H_Seq)) then
declare
Handler : Node_Id := First (Exception_Handlers (H_Seq));
begin
while Present (Handler) loop
- Ent := First_Local_Scope (Statements (Handler));
- if Present (Ent) then
- First_Ent := Ent;
- exit;
- end if;
+ Reset_Scopes_To_Block_Elab_Proc (Statements (Handler));
Next (Handler);
end loop;
end;
end if;
- if Present (Ent) then
- Elab_Proc :=
- Make_Defining_Identifier (Loc,
- Chars => New_Internal_Name ('I'));
-
+ if Present (Block_Elab_Proc) then
Elab_Body :=
Make_Subprogram_Body (Loc,
Specification =>
Make_Procedure_Specification (Loc,
- Defining_Unit_Name => Elab_Proc),
+ Defining_Unit_Name => Block_Elab_Proc),
Declarations => New_List,
Handled_Statement_Sequence =>
Relocate_Node (Handled_Statement_Sequence (N)));
Elab_Call :=
Make_Procedure_Call_Statement (Loc,
- Name => New_Occurrence_Of (Elab_Proc, Loc));
+ Name => New_Occurrence_Of (Block_Elab_Proc, Loc));
Append_To (Declarations (N), Elab_Body);
Analyze (Elab_Body);
- Set_Has_Nested_Subprogram (Elab_Proc);
+ Set_Has_Nested_Subprogram (Block_Elab_Proc);
Set_Handled_Statement_Sequence (N,
Make_Handled_Sequence_Of_Statements (Loc,
@@ -4202,85 +4205,81 @@ package body Exp_Ch7 is
Analyze (Elab_Call);
- -- The scope of all blocks and loops in the elaboration code is
- -- now the constructed elaboration procedure. Nested subprograms
- -- within those blocks will have activation records if they
- -- contain references to entities in the enclosing block or
- -- the package itself.
-
- Ent := First_Ent;
- while Present (Ent) loop
- Set_Scope (Ent, Elab_Proc);
- Next_Entity (Ent);
- end loop;
-
- if Present (Loop_Id) then
- Set_Scope (Loop_Id, Elab_Proc);
- end if;
+ -- Could we reset the scopes of entities associated with the new
+ -- procedure here via a loop over entities rather than doing it in
+ -- the recursive Reset_Scopes_To_Elab_Proc procedure???
end if;
end if;
end Check_Unnesting_Elaboration_Code;
- -------------------------------------
- -- Check_Unnesting_In_Declarations --
- -------------------------------------
+ ---------------------------------------
+ -- Check_Unnesting_In_Decls_Or_Stmts --
+ ---------------------------------------
- procedure Check_Unnesting_In_Declarations (Decls : List_Id) is
- Decl : Node_Id;
- Ent : Entity_Id;
- Loc : Source_Ptr;
- Local_Body : Node_Id;
- Local_Call : Node_Id;
- Local_Proc : Entity_Id;
+ procedure Check_Unnesting_In_Decls_Or_Stmts (Decls_Or_Stmts : List_Id) is
+ Decl_Or_Stmt : Node_Id;
begin
- Local_Call := Empty;
-
if Unnest_Subprogram_Mode
- and then Present (Decls)
- and then Is_Compilation_Unit (Current_Scope)
+ and then Present (Decls_Or_Stmts)
then
- Decl := First (Decls);
- while Present (Decl) loop
- if Nkind (Decl) = N_Block_Statement
- and then Contains_Subprogram (Entity (Identifier (Decl)))
+ Decl_Or_Stmt := First (Decls_Or_Stmts);
+ while Present (Decl_Or_Stmt) loop
+ if Nkind (Decl_Or_Stmt) = N_Block_Statement
+ and then Contains_Subprogram (Entity (Identifier (Decl_Or_Stmt)))
then
- Ent := First_Entity (Entity (Identifier (Decl)));
- Loc := Sloc (Decl);
- Local_Proc :=
- Make_Defining_Identifier (Loc,
- Chars => New_Internal_Name ('P'));
-
- Local_Body :=
- Make_Subprogram_Body (Loc,
- Specification =>
- Make_Procedure_Specification (Loc,
- Defining_Unit_Name => Local_Proc),
- Declarations => Declarations (Decl),
- Handled_Statement_Sequence =>
- Handled_Statement_Sequence (Decl));
-
- Rewrite (Decl, Local_Body);
- Analyze (Decl);
- Set_Has_Nested_Subprogram (Local_Proc);
-
- Local_Call :=
- Make_Procedure_Call_Statement (Loc,
- Name => New_Occurrence_Of (Local_Proc, Loc));
+ Unnest_Block (Decl_Or_Stmt);
- Insert_After (Decl, Local_Call);
- Analyze (Local_Call);
+ elsif Nkind (Decl_Or_Stmt) = N_Package_Declaration
+ and then not Modify_Tree_For_C
+ then
+ Check_Unnesting_In_Decls_Or_Stmts
+ (Visible_Declarations (Specification (Decl_Or_Stmt)));
+ Check_Unnesting_In_Decls_Or_Stmts
+ (Private_Declarations (Specification (Decl_Or_Stmt)));
- while Present (Ent) loop
- Set_Scope (Ent, Local_Proc);
- Next_Entity (Ent);
- end loop;
+ elsif Nkind (Decl_Or_Stmt) = N_Package_Body
+ and then not Modify_Tree_For_C
+ then
+ Check_Unnesting_In_Decls_Or_Stmts (Declarations (Decl_Or_Stmt));
+ if Present (Statements
+ (Handled_Statement_Sequence (Decl_Or_Stmt)))
+ then
+ Check_Unnesting_In_Decls_Or_Stmts (Statements
+ (Handled_Statement_Sequence (Decl_Or_Stmt)));
+ Check_Unnesting_In_Handlers (Decl_Or_Stmt);
+ end if;
end if;
- Next (Decl);
+ Next (Decl_Or_Stmt);
end loop;
end if;
- end Check_Unnesting_In_Declarations;
+ end Check_Unnesting_In_Decls_Or_Stmts;
+
+ ---------------------------------
+ -- Check_Unnesting_In_Handlers --
+ ---------------------------------
+
+ procedure Check_Unnesting_In_Handlers (N : Node_Id) is
+ Stmt_Seq : constant Node_Id := Handled_Statement_Sequence (N);
+
+ begin
+ if Present (Stmt_Seq)
+ and then Present (Exception_Handlers (Stmt_Seq))
+ then
+ declare
+ Handler : Node_Id := First (Exception_Handlers (Stmt_Seq));
+ begin
+ while Present (Handler) loop
+ if Present (Statements (Handler)) then
+ Check_Unnesting_In_Decls_Or_Stmts (Statements (Handler));
+ end if;
+
+ Next (Handler);
+ end loop;
+ end;
+ end if;
+ end Check_Unnesting_In_Handlers;
------------------------------
-- Check_Visibly_Controlled --
@@ -5036,8 +5035,20 @@ package body Exp_Ch7 is
-- end of the body statements.
Expand_Pragma_Initial_Condition (Spec_Id, N);
- Check_Unnesting_Elaboration_Code (N);
- Check_Unnesting_In_Declarations (Declarations (N));
+
+ -- If this is a library-level package and unnesting is enabled,
+ -- check for the presence of blocks with nested subprograms occurring
+ -- in elaboration code, and generate procedures to encapsulate the
+ -- blocks in case the nested subprograms make up-level references.
+
+ if Unnest_Subprogram_Mode
+ and then
+ Is_Library_Level_Entity (Current_Scope)
+ then
+ Check_Unnesting_Elaboration_Code (N);
+ Check_Unnesting_In_Decls_Or_Stmts (Declarations (N));
+ Check_Unnesting_In_Handlers (N);
+ end if;
Pop_Scope;
end if;
@@ -5196,8 +5207,17 @@ package body Exp_Ch7 is
Set_Finalizer (Id, Fin_Id);
end if;
- Check_Unnesting_In_Declarations (Visible_Declarations (Spec));
- Check_Unnesting_In_Declarations (Private_Declarations (Spec));
+ -- If this is a library-level package and unnesting is enabled,
+ -- check for the presence of blocks with nested subprograms occurring
+ -- in elaboration code, and generate procedures to encapsulate the
+ -- blocks in case the nested subprograms make up-level references.
+
+ if Unnest_Subprogram_Mode
+ and then Is_Library_Level_Entity (Current_Scope)
+ then
+ Check_Unnesting_In_Decls_Or_Stmts (Visible_Declarations (Spec));
+ Check_Unnesting_In_Decls_Or_Stmts (Private_Declarations (Spec));
+ end if;
end Expand_N_Package_Declaration;
----------------------------
@@ -9180,6 +9200,62 @@ package body Exp_Ch7 is
Store_Actions_In_Scope (Cleanup, L);
end Store_Cleanup_Actions_In_Scope;
+ ------------------
+ -- Unnest_Block --
+ ------------------
+
+ procedure Unnest_Block (Decl : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (Decl);
+ Ent : Entity_Id;
+ Local_Body : Node_Id;
+ Local_Call : Node_Id;
+ Local_Proc : Entity_Id;
+ Local_Scop : Entity_Id;
+
+ begin
+ Local_Scop := Entity (Identifier (Decl));
+ Ent := First_Entity (Local_Scop);
+
+ Local_Proc :=
+ Make_Defining_Identifier (Loc,
+ Chars => New_Internal_Name ('P'));
+
+ Local_Body :=
+ Make_Subprogram_Body (Loc,
+ Specification =>
+ Make_Procedure_Specification (Loc,
+ Defining_Unit_Name => Local_Proc),
+ Declarations => Declarations (Decl),
+ Handled_Statement_Sequence =>
+ Handled_Statement_Sequence (Decl));
+
+ Rewrite (Decl, Local_Body);
+ Analyze (Decl);
+ Set_Has_Nested_Subprogram (Local_Proc);
+
+ Local_Call :=
+ Make_Procedure_Call_Statement (Loc,
+ Name => New_Occurrence_Of (Local_Proc, Loc));
+
+ Insert_After (Decl, Local_Call);
+ Analyze (Local_Call);
+
+ -- The new subprogram has the same scope as the original block
+
+ Set_Scope (Local_Proc, Scope (Local_Scop));
+
+ -- And the entity list of the new procedure is that of the block
+
+ Set_First_Entity (Local_Proc, Ent);
+
+ -- Reset the scopes of all the entities to the new procedure
+
+ while Present (Ent) loop
+ Set_Scope (Ent, Local_Proc);
+ Next_Entity (Ent);
+ end loop;
+ end Unnest_Block;
+
--------------------------------
-- Wrap_Transient_Declaration --
--------------------------------