From 4f31d6dbb8deafd7ab54e70eddfd931b10b3309b Mon Sep 17 00:00:00 2001 From: Gary Dismukes Date: Fri, 24 Jan 2020 14:11:47 -0500 Subject: [PATCH] [Ada] Implement AI12-0275 (Make subtype_mark optional in object renamings) 2020-06-04 Gary Dismukes gcc/ada/ * par-ch3.adb (P_Identifier_Declarations): Add parsing of object renamings that have neither a subtype_mark nor an access_definition. Issue an error if the version is earlier than Ada_2020, and suggest using -gnatX. * sem_ch8.adb (Analyze_Object_Renaming): Handle object_renaming_declarations that don't have an explicit subtype. Errors are issued when the name is inappropriate or ambiguous, and otherwise the Etype of the renaming entity is set from the Etype of the renamed object. * sem_util.adb (Has_Null_Exclusion): Allow for the case of no subtype given in an N_Object_Renaming_Declaration. * sprint.adb (Sprint_Node_Actual): Handle printing of N_Object_Renaming_Declarations that are specified without an explicit subtype. --- gcc/ada/par-ch3.adb | 26 +++++++++++ gcc/ada/sem_ch8.adb | 106 +++++++++++++++++++++++++++++++++++++++++-- gcc/ada/sem_util.adb | 10 +++- gcc/ada/sprint.adb | 10 +++- 4 files changed, 145 insertions(+), 7 deletions(-) diff --git a/gcc/ada/par-ch3.adb b/gcc/ada/par-ch3.adb index a54577e665e..9065f4bb75c 100644 --- a/gcc/ada/par-ch3.adb +++ b/gcc/ada/par-ch3.adb @@ -1480,6 +1480,32 @@ package body Ch3 is Done := False; return; + -- AI12-0275: Object renaming declaration without subtype_mark or + -- access_definition + + elsif Token = Tok_Renames then + if Ada_Version < Ada_2020 then + Error_Msg_SC + ("object renaming without subtype is an Ada 202x feature"); + Error_Msg_SC ("\compile with -gnatX"); + end if; + + Scan; -- past renames + + Decl_Node := + New_Node (N_Object_Renaming_Declaration, Ident_Sloc); + Set_Name (Decl_Node, P_Name); + Set_Defining_Identifier (Decl_Node, Idents (1)); + + P_Aspect_Specifications (Decl_Node, Semicolon => False); + + T_Semicolon; + + Append (Decl_Node, Decls); + Done := False; + + return; + -- Otherwise we have an error situation else diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb index 76f696b32ed..4a730fc8ae8 100644 --- a/gcc/ada/sem_ch8.adb +++ b/gcc/ada/sem_ch8.adb @@ -906,10 +906,108 @@ package body Sem_Ch8 is Find_Type (Subtype_Mark (N)); end if; - elsif Present (Subtype_Mark (N)) then - Find_Type (Subtype_Mark (N)); - T := Entity (Subtype_Mark (N)); - Analyze (Nam); + elsif Present (Subtype_Mark (N)) + or else not Present (Access_Definition (N)) + then + if Present (Subtype_Mark (N)) then + Find_Type (Subtype_Mark (N)); + T := Entity (Subtype_Mark (N)); + Analyze (Nam); + + -- AI12-0275: Case of object renaming without a subtype_mark + + else + Analyze (Nam); + + -- Normal case of no overloading in object name + + if not Is_Overloaded (Nam) then + + -- Catch error cases (such as attempting to rename a procedure + -- or package) using the shorthand form. + + if No (Etype (Nam)) + or else Etype (Nam) = Standard_Void_Type + then + Error_Msg_N ("object name expected in renaming", Nam); + + Set_Ekind (Id, E_Variable); + Set_Etype (Id, Any_Type); + + return; + + else + T := Etype (Nam); + end if; + + -- Case of overloaded name, which will be illegal if there's more + -- than one acceptable interpretation (such as overloaded function + -- calls). + + else + declare + I : Interp_Index; + I1 : Interp_Index; + It : Interp; + It1 : Interp; + Nam1 : Entity_Id; + + begin + -- More than one candidate interpretation is available + + -- Remove procedure calls, which syntactically cannot appear + -- in this context, but which cannot be removed by type + -- checking, because the context does not impose a type. + + Get_First_Interp (Nam, I, It); + while Present (It.Typ) loop + if It.Typ = Standard_Void_Type then + Remove_Interp (I); + end if; + + Get_Next_Interp (I, It); + end loop; + + Get_First_Interp (Nam, I, It); + I1 := I; + It1 := It; + + -- If there's no type present, we have an error case (such + -- as overloaded procedures named in the object renaming). + + if No (It.Typ) then + Error_Msg_N ("object name expected in renaming", Nam); + + Set_Ekind (Id, E_Variable); + Set_Etype (Id, Any_Type); + + return; + end if; + + Get_Next_Interp (I, It); + + if Present (It.Typ) then + Nam1 := It1.Nam; + It1 := Disambiguate (Nam, I1, I, Any_Type); + + if It1 = No_Interp then + Error_Msg_N ("ambiguous name in object renaming", Nam); + + Error_Msg_Sloc := Sloc (It.Nam); + Error_Msg_N ("\\possible interpretation#!", Nam); + + Error_Msg_Sloc := Sloc (Nam1); + Error_Msg_N ("\\possible interpretation#!", Nam); + + return; + end if; + end if; + + Set_Etype (Nam, It1.Typ); + T := It1.Typ; + end; + end if; + end if; -- The object renaming declaration may become Ghost if it renames a -- Ghost entity. diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb index dff9f81763c..49594e47aea 100644 --- a/gcc/ada/sem_util.adb +++ b/gcc/ada/sem_util.adb @@ -11726,7 +11726,6 @@ package body Sem_Util is when N_Component_Definition | N_Formal_Object_Declaration - | N_Object_Renaming_Declaration => if Present (Subtype_Mark (N)) then return Null_Exclusion_Present (N); @@ -11734,6 +11733,15 @@ package body Sem_Util is return Null_Exclusion_Present (Access_Definition (N)); end if; + when N_Object_Renaming_Declaration => + if Present (Subtype_Mark (N)) then + return Null_Exclusion_Present (N); + elsif Present (Access_Definition (N)) then + return Null_Exclusion_Present (Access_Definition (N)); + else + return False; -- Case of no subtype in renaming (AI12-0275) + end if; + when N_Discriminant_Specification => if Nkind (Discriminant_Type (N)) = N_Access_Definition then return Null_Exclusion_Present (Discriminant_Type (N)); diff --git a/gcc/ada/sprint.adb b/gcc/ada/sprint.adb index 51f0bf41022..f177981de70 100644 --- a/gcc/ada/sprint.adb +++ b/gcc/ada/sprint.adb @@ -2441,14 +2441,15 @@ package body Sprint is Write_Indent; Set_Debug_Sloc; Sprint_Node (Defining_Identifier (Node)); - Write_Str (" : "); -- Ada 2005 (AI-230): Access renamings if Present (Access_Definition (Node)) then + Write_Str (" : "); Sprint_Node (Access_Definition (Node)); elsif Present (Subtype_Mark (Node)) then + Write_Str (" : "); -- Ada 2005 (AI-423): Object renaming with a null exclusion @@ -2458,8 +2459,13 @@ package body Sprint is Sprint_Node (Subtype_Mark (Node)); + -- AI12-0275: Object_Renaming_Declaration without explicit subtype + + elsif Ada_Version >= Ada_2020 then + null; + else - Write_Str (" ??? "); + Write_Str (" : ??? "); end if; Write_Str_With_Col_Check (" renames "); -- 2.30.2