[Ada] GNAT-LLVM unnesting issues in elaboration code
gcc/ada/ * exp_ch7.adb (Check_Unnesting_In_Decls_Or_Stmts): In the case of an if-statement, call Unnest_If_Statement to determine whether there are nested subprograms in any of the statement lists of the "if" parts that require a wrapping procedure to handle possible up-level refeferences. (Unnest_Block): Call Check_Unnesting_In_Handlers to do unnesting of subprograms in exception handlers of the block statement. (Unnest_If_Statement): New procedure to traverse the parts of an if-statement and create wrapper procedures as needed to encapsulate nested subprograms that may make up-level references. (Check_Stmts_For_Subp_Unnesting): New support procedure in Unnest_If_Statement to traverse a statement list looking for top-level subprogram bodies that require wrapping inside a procedure (via Unnest_Statement_List) as well as possibly having other statements (block, loop, if) that may themselves require an unnesting transformation (via Check_Unnesting_In_Decls_Or_Stmts). (Unnest_Statement_List): New support procedure to traverse the statements of a statement list that contains subprogram bodies at the top level and replace the statement list with a wrapper procedure body encapsulating the statements and a call to the procedure.
This commit is contained in:
Gary Dismukes
Pierre-Marie de Rodat
parent
6f238680dd
commit
0574695888
@ -398,6 +398,31 @@ package body Exp_Ch7 is
|
||||
-- actions or secondary-stack management, in which case the nested
|
||||
-- subprogram is a finalizer.
|
||||
|
||||
procedure Unnest_If_Statement (If_Stmt : Node_Id);
|
||||
-- The separate statement lists associated with an if-statement (then part,
|
||||
-- elsif parts, else part) may require unnesting if they directly contain
|
||||
-- a subprogram body that references up-level objects. Each statement list
|
||||
-- is traversed to locate such subprogram bodies, and if a part's statement
|
||||
-- list contains a body, then the list is replaced with a new procedure
|
||||
-- containing the part's statements followed by a call to the procedure.
|
||||
-- Furthermore, any nested blocks, loops, or if statements will also be
|
||||
-- traversed to determine the need for further unnesting transformations.
|
||||
|
||||
procedure Unnest_Statement_List (Stmts : in out List_Id);
|
||||
-- A list of statements that directly contains a subprogram at its outer
|
||||
-- level, that may reference objects declared in that same statement list,
|
||||
-- is rewritten as a procedure containing the statement list Stmts (which
|
||||
-- includes any such objects as well as the nested subprogram), followed by
|
||||
-- a call to the new procedure, and Stmts becomes the list containing the
|
||||
-- procedure and the call. This ensures that Unnest_Subprogram will later
|
||||
-- properly handle up-level references from the nested subprogram to
|
||||
-- objects declared earlier in statement list, by creating an activation
|
||||
-- record and passing it to the nested subprogram. This procedure also
|
||||
-- resets the Scope of objects declared in the statement list, as well as
|
||||
-- the Scope of the nested subprogram, to refer to the new procedure.
|
||||
-- Also, the new procedure is marked Has_Nested_Subprogram, so this should
|
||||
-- only be called when known that the statement list contains a subprogram.
|
||||
|
||||
procedure Unnest_Loop (Loop_Stmt : Node_Id);
|
||||
-- Top-level Loops that contain nested subprograms with up-level references
|
||||
-- need to have activation records. We do this by rewriting the loop as a
|
||||
@ -4233,6 +4258,17 @@ package body Exp_Ch7 is
|
||||
then
|
||||
Unnest_Block (Decl_Or_Stmt);
|
||||
|
||||
-- If-statements may contain subprogram bodies at the outer level
|
||||
-- of their statement lists, and the subprograms may make up-level
|
||||
-- references (such as to objects declared in the same statement
|
||||
-- list). Unlike block and loop cases, however, we don't have an
|
||||
-- entity on which to test the Contains_Subprogram flag, so
|
||||
-- Unnest_If_Statement must traverse the statement lists to
|
||||
-- determine whether there are nested subprograms present.
|
||||
|
||||
elsif Nkind (Decl_Or_Stmt) = N_If_Statement then
|
||||
Unnest_If_Statement (Decl_Or_Stmt);
|
||||
|
||||
elsif Nkind (Decl_Or_Stmt) = N_Loop_Statement then
|
||||
declare
|
||||
Id : constant Entity_Id :=
|
||||
@ -9261,6 +9297,11 @@ package body Exp_Ch7 is
|
||||
Handled_Statement_Sequence =>
|
||||
Handled_Statement_Sequence (Decl));
|
||||
|
||||
-- Handlers in the block may contain nested subprograms that require
|
||||
-- unnesting.
|
||||
|
||||
Check_Unnesting_In_Handlers (Local_Body);
|
||||
|
||||
Rewrite (Decl, Local_Body);
|
||||
Analyze (Decl);
|
||||
Set_Has_Nested_Subprogram (Local_Proc);
|
||||
@ -9288,6 +9329,94 @@ package body Exp_Ch7 is
|
||||
end loop;
|
||||
end Unnest_Block;
|
||||
|
||||
-------------------------
|
||||
-- Unnest_If_Statement --
|
||||
-------------------------
|
||||
|
||||
procedure Unnest_If_Statement (If_Stmt : Node_Id) is
|
||||
|
||||
procedure Check_Stmts_For_Subp_Unnesting (Stmts : in out List_Id);
|
||||
-- A list of statements (that may be a list associated with a then,
|
||||
-- elsif, or else part of an if-statement) is traversed at the top
|
||||
-- level to determine whether it contains a subprogram body, and if so,
|
||||
-- the statements will be replaced with a new procedure body containing
|
||||
-- the statements followed by a call to the procedure. The individual
|
||||
-- statements may also be blocks, loops, or other if statements that
|
||||
-- themselves may require contain nested subprograms needing unnesting.
|
||||
|
||||
procedure Check_Stmts_For_Subp_Unnesting (Stmts : in out List_Id) is
|
||||
Subp_Found : Boolean := False;
|
||||
|
||||
begin
|
||||
if Is_Empty_List (Stmts) then
|
||||
return;
|
||||
end if;
|
||||
|
||||
declare
|
||||
Stmt : Node_Id := First (Stmts);
|
||||
begin
|
||||
while Present (Stmt) loop
|
||||
if Nkind (Stmt) = N_Subprogram_Body then
|
||||
Subp_Found := True;
|
||||
exit;
|
||||
end if;
|
||||
|
||||
Next (Stmt);
|
||||
end loop;
|
||||
end;
|
||||
|
||||
-- The statements themselves may be blocks, loops, etc. that in turn
|
||||
-- contain nested subprograms requiring an unnesting transformation.
|
||||
-- We perform this traversal after looking for subprogram bodies, to
|
||||
-- avoid considering procedures created for one of those statements
|
||||
-- (such as a block rewritten as a procedure) as a nested subprogram
|
||||
-- of the statement list (which could result in an unneeded wrapper
|
||||
-- procedure).
|
||||
|
||||
Check_Unnesting_In_Decls_Or_Stmts (Stmts);
|
||||
|
||||
-- If there was a top-level subprogram body in the statement list,
|
||||
-- then perform an unnesting transformation on the list by replacing
|
||||
-- the statements with a wrapper procedure body containing the
|
||||
-- original statements followed by a call to that procedure.
|
||||
|
||||
if Subp_Found then
|
||||
Unnest_Statement_List (Stmts);
|
||||
end if;
|
||||
end Check_Stmts_For_Subp_Unnesting;
|
||||
|
||||
-- Local variables
|
||||
|
||||
Then_Stmts : List_Id := Then_Statements (If_Stmt);
|
||||
Else_Stmts : List_Id := Else_Statements (If_Stmt);
|
||||
|
||||
-- Start of processing for Unnest_If_Statement
|
||||
|
||||
begin
|
||||
Check_Stmts_For_Subp_Unnesting (Then_Stmts);
|
||||
Set_Then_Statements (If_Stmt, Then_Stmts);
|
||||
|
||||
if not Is_Empty_List (Elsif_Parts (If_Stmt)) then
|
||||
declare
|
||||
Elsif_Part : Node_Id :=
|
||||
First (Elsif_Parts (If_Stmt));
|
||||
Elsif_Stmts : List_Id;
|
||||
begin
|
||||
while Present (Elsif_Part) loop
|
||||
Elsif_Stmts := Then_Statements (Elsif_Part);
|
||||
|
||||
Check_Stmts_For_Subp_Unnesting (Elsif_Stmts);
|
||||
Set_Then_Statements (Elsif_Part, Elsif_Stmts);
|
||||
|
||||
Next (Elsif_Part);
|
||||
end loop;
|
||||
end;
|
||||
end if;
|
||||
|
||||
Check_Stmts_For_Subp_Unnesting (Else_Stmts);
|
||||
Set_Else_Statements (If_Stmt, Else_Stmts);
|
||||
end Unnest_If_Statement;
|
||||
|
||||
-----------------
|
||||
-- Unnest_Loop --
|
||||
-----------------
|
||||
@ -9349,6 +9478,75 @@ package body Exp_Ch7 is
|
||||
-- same loop entity that now belongs to the copied loop statement.
|
||||
end Unnest_Loop;
|
||||
|
||||
---------------------------
|
||||
-- Unnest_Statement_List --
|
||||
---------------------------
|
||||
|
||||
procedure Unnest_Statement_List (Stmts : in out List_Id) is
|
||||
Loc : constant Source_Ptr := Sloc (First (Stmts));
|
||||
Local_Body : Node_Id;
|
||||
Local_Call : Node_Id;
|
||||
Local_Proc : Entity_Id;
|
||||
New_Stmts : constant List_Id := Empty_List;
|
||||
|
||||
begin
|
||||
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 => Empty_List,
|
||||
Handled_Statement_Sequence =>
|
||||
Make_Handled_Sequence_Of_Statements (Loc,
|
||||
Statements => Stmts));
|
||||
|
||||
Append_To (New_Stmts, Local_Body);
|
||||
|
||||
Analyze (Local_Body);
|
||||
|
||||
Set_Has_Nested_Subprogram (Local_Proc);
|
||||
|
||||
Local_Call :=
|
||||
Make_Procedure_Call_Statement (Loc,
|
||||
Name => New_Occurrence_Of (Local_Proc, Loc));
|
||||
|
||||
Append_To (New_Stmts, Local_Call);
|
||||
Analyze (Local_Call);
|
||||
|
||||
-- Traverse the statements, and for any that are declarations or
|
||||
-- subprogram bodies that have entities, set the Scope of those
|
||||
-- entities to the new procedure's Entity_Id.
|
||||
|
||||
declare
|
||||
Stmt : Node_Id := First (Stmts);
|
||||
|
||||
begin
|
||||
while Present (Stmt) loop
|
||||
case Nkind (Stmt) is
|
||||
when N_Declaration
|
||||
| N_Renaming_Declaration
|
||||
=>
|
||||
Set_Scope (Defining_Identifier (Stmt), Local_Proc);
|
||||
|
||||
when N_Subprogram_Body =>
|
||||
Set_Scope
|
||||
(Defining_Unit_Name (Specification (Stmt)), Local_Proc);
|
||||
|
||||
when others =>
|
||||
null;
|
||||
end case;
|
||||
|
||||
Next (Stmt);
|
||||
end loop;
|
||||
end;
|
||||
|
||||
Stmts := New_Stmts;
|
||||
end Unnest_Statement_List;
|
||||
|
||||
--------------------------------
|
||||
-- Wrap_Transient_Declaration --
|
||||
--------------------------------
|
||||
|
||||
Loading…
Reference in New Issue
Block a user