From: Ed Schonberg Date: Tue, 11 Dec 2018 11:09:57 +0000 (+0000) Subject: [Ada] Additionsal trasformations for unnesting in package bodies X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=66f84da8f3232cc104cacf16b2c1f99d7f8ba676;p=gcc.git [Ada] Additionsal trasformations for unnesting in package bodies This patch extends the previous algorithm for creating an explicit elaboration procedure for a package body when expansion generates subprograms in the statement part of the body. For unnesting to work properly, these subprograms must appear within an explicit subprogram body so that uplevel references can be placed in the proper activation record. Ongoing work for LLVM generation. 2018-12-11 Ed Schonberg gcc/ada/ * exp_ch7.adb (Check_Unnesting_Elaboration_Code): Extend algorithm to cover subprograms generated in nested loops and in exception handlers, in order to build an explicit elaboration procedure in more complex cases. From-SVN: r266987 --- diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 4fcbaa943d3..f242a2fa3d8 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,10 @@ +2018-12-11 Ed Schonberg + + * exp_ch7.adb (Check_Unnesting_Elaboration_Code): Extend + algorithm to cover subprograms generated in nested loops and in + exception handlers, in order to build an explicit elaboration + procedure in more complex cases. + 2018-12-11 Jerome Lambourg * Makefile.rtl, gcc-interface/Makefile.in: Remove crtbe bits for diff --git a/gcc/ada/exp_ch7.adb b/gcc/ada/exp_ch7.adb index c8f39e7b4ee..a21b707fef4 100644 --- a/gcc/ada/exp_ch7.adb +++ b/gcc/ada/exp_ch7.adb @@ -3996,15 +3996,23 @@ package body Exp_Ch7 is -------------------------------------- procedure Check_Unnesting_Elaboration_Code (N : Node_Id) is - Loc : constant Source_Ptr := Sloc (N); + Loc : constant Source_Ptr := Sloc (N); + First_Ent : Entity_Id := Empty; + Loop_Id : Entity_Id := Empty; function Contains_Subprogram (Blk : Entity_Id) return Boolean; -- Check recursively whether a loop or block contains a subprogram that -- may need an activation record. function First_Local_Scope (L : List_Id) return Entity_Id; - -- Find first block or loop that contains a subprogram and is not itself - -- nested within another local scope. + -- Find first entity in the elaboration code of the body that + -- contains or represents a subprogrsam 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 hew elboration procedure. + -- This is needed for subsequent unnesting, which depends on the + -- scope links to determine the nesting level of each subprogram. -------------------------- -- Contains_Subprogram -- @@ -4037,6 +4045,7 @@ package body Exp_Ch7 is ----------------------- function First_Local_Scope (L : List_Id) return Entity_Id is + Id : Entity_Id; Scop : Entity_Id; Stat : Node_Id; @@ -4045,13 +4054,27 @@ package body Exp_Ch7 is while Present (Stat) loop case Nkind (Stat) is when N_Block_Statement => - if Present (Identifier (Stat)) then - return Entity (Identifier (Stat)); + Id := Entity (Identifier (Stat)); + if No (First_Ent) then + First_Ent := Id; + end if; + + if Present (Id) and then Contains_Subprogram (Id) then + return Id; end if; when N_Loop_Statement => - if Contains_Subprogram (Entity (Identifier (Stat))) then - return Entity (Identifier (Stat)); + Id := Entity (Identifier (Stat)); + if No (First_Ent) then + First_Ent := Id; + end if; + + if Contains_Subprogram (Id) then + if Scope (Id) = Current_Scope then + Loop_Id := Id; + end if; + + return Id; end if; when N_If_Statement => @@ -4101,7 +4124,12 @@ package body Exp_Ch7 is end; when N_Subprogram_Body => - return Defining_Entity (Stat); + Id := Defining_Entity (Stat); + if No (First_Ent) then + First_Ent := Id; + end if; + + return Id; when others => null; @@ -4115,6 +4143,7 @@ package body Exp_Ch7 is -- Local variables + H_Seq : constant Node_Id := Handled_Statement_Sequence (N); Elab_Body : Node_Id; Elab_Call : Node_Id; Elab_Proc : Entity_Id; @@ -4124,11 +4153,30 @@ package body Exp_Ch7 is begin if Unnest_Subprogram_Mode - and then Present (Handled_Statement_Sequence (N)) + and then Present (H_Seq) and then Is_Compilation_Unit (Current_Scope) then Ent := - First_Local_Scope (Statements (Handled_Statement_Sequence (N))); + First_Local_Scope (Statements (H_Seq)); + + -- There msy be subprograms declared in the exception handlers + -- of the current body. + + if No (Ent) and then 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; + + Next (Handler); + end loop; + end; + end if; if Present (Ent) then Elab_Proc := @@ -4161,12 +4209,18 @@ package body Exp_Ch7 is -- 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. + -- 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; end if; end if; end Check_Unnesting_Elaboration_Code;