[Ada] Add support for defaulted Storage_Model_Type aspect and subaspects

The compiler currently rejects a Storage_Model_Type aspect that is not
specified with an aggregate, or that has an aggregate that does not
specify all defined "subaspects" (Address_Type, Null_Address, Allocate,
etc.). The RFC for this feature defines the aspect to fully default to
the native memory model when no aggregate is given, and also allows any
subaspects to be specified and others to default in the case where the
address type is the native address type (System.Address), whether that
address type is explicitly specified or defaulted. This set of changes
now supports that defaulting semantics. Note that the subaspect
retrieval functions in Sem_Util.Storage_Model_Support (which are called
by the compiler back ends) will now return Empty for any subprogram
subaspects (Allocate, Deallocate, etc.) that are defaulted in the aspect
(that is, in the native model case where the address type is
System.Address).  Also in the native case, retrieval of defaulted
subaspects Address_Type and Null_Address will return the entities for
System.Address and System.Null_Address, respectively. Additionally,
error checks for multiple associations given for the same subaspect are
now done.

gcc/ada/

	* aspects.ads (Aspect_Argument): Change the association for
	Aspect_Storage_Model_Type from Expression to
	Optional_Expression.
	* exp_util.ads (Find_Storage_Op): Update comment to indicate
	that Empty can be returned in the case where a storage-model
	operation is defaulted.
	* exp_util.adb (Find_Storage_Op): Allow the function to return
	Empty in Storage_Model_Type case rather than raising
	Program_Error, so that Procedure_To_Call fields in N_Allocator
	and N_Free_Statement nodes will be set to Empty in the defaulted
	native storage-model case.
	* sem_ch13.adb: Add with and use of System.Case_Util (and
	reformat context_clause).
	(Check_Aspect_At_Freeze_Point): Return with no action for a
	Storage_Model_Type aspect with no expression (fully-defaulted
	native memory-model case).
	(Resolve_Storage_Model_Type_Argument): If an Address_Type has
	not been explicitly specified, then set Addr_Type to denote type
	System.Address.
	(Validate_Storage_Model_Type_Aspect): Return immediately in the
	case where the aspect has no Expression (fully-defaulted native
	memory-model case).  No longer issue an error when Address_Type
	isn't specified, and instead use type System.Address as the
	default address type. When the address type is
	System.Address (whether specified or defaulted), no longer issue
	errors for any other "subaspects" that aren't specified, since
	in that case those are allowed to default as well. Remove ???
	comment about needing to check for duplicates, which is now
	addressed.
	(Check_And_Resolve_Storage_Model_Type_Argument): New procedure
	to check that an association for a storage-model subaspect in
	the aggregate has not been specified earlier in the aggregate,
	and to then resolve the expression of the association and save
	the resolved entity. Called by
	Validate_Storage_Model_Type_Aspect.
	* sem_util.ads (Storage_Model_Support): Update comments on specs
	of the functions Get_Storage_Model_Type_Entity,
	Storage_Model_Address_Type, and Storage_Model_Null_Address to
	indicate the behavior when the address type is System.Address
	(the native memory-model case).
	* sem_util.adb
	(Storage_Model_Support.Get_Storage_Model_Type_Entity): Suppress
	the search for the given subaspect name (Nam) when the
	Storage_Model_Type aspect is fully defaulted (i.e., no
	Expression is present) and simply return. In cases where the
	search is done, but no association that matches Nam is found,
	return System.Address for the Name_Address_Type case, return
	System.Null_Address for the Name_Null_Address case, and return
	Empty for all other cases.

diff --git a/gcc/ada/aspects.ads b/gcc/ada/aspects.ads
index 658a85991532a67302885bb7cb792636a3b33f6e..6559cda293a2d03bf76959ee1dd20ccf99d33bf4 100644 (file)
--- a/gcc/ada/aspects.ads
+++ b/gcc/ada/aspects.ads
@@ -441,7 +441,7 @@ package Aspects is
       Aspect_SPARK_Mode                 => Optional_Name,
       Aspect_Stable_Properties          => Expression,
       Aspect_Static_Predicate           => Expression,
-      Aspect_Storage_Model_Type         => Expression,
+      Aspect_Storage_Model_Type         => Optional_Expression,
       Aspect_Storage_Pool               => Name,
       Aspect_Storage_Size               => Expression,
       Aspect_Stream_Size                => Expression,

diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 8557e4bb4bd95608fe292ba8acb3722edb8ba84d..3286bf6c89634e603802b72f7b05a7921d301467 100644 (file)
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -6406,16 +6406,7 @@ package body Exp_Util is
 
    begin
       if Has_Storage_Model_Type_Aspect (Typ) then
-         declare
-            SMT_Op : constant Entity_Id :=
-                       Get_Storage_Model_Type_Entity (Typ, Nam);
-         begin
-            if not Present (SMT_Op) then
-               raise Program_Error;
-            else
-               return SMT_Op;
-            end if;
-         end;
+         return Get_Storage_Model_Type_Entity (Typ, Nam);
 
       --  Otherwise we assume that Typ is a descendant of Root_Storage_Pool
 

diff --git a/gcc/ada/exp_util.ads b/gcc/ada/exp_util.ads
index 1b7be3a2831adc068a7ca45a97a2c5013e6085a6..d854672ccd8eb0aae7f92d9fea3a392cb64870e6 100644 (file)
--- a/gcc/ada/exp_util.ads
+++ b/gcc/ada/exp_util.ads
@@ -623,8 +623,10 @@ package Exp_Util is
    --  specifies aspect Storage_Model_Type, returns the Entity_Id of the
    --  subprogram associated with Nam, which must either be a primitive op of
    --  the type in the case of a storage pool, or the operation corresponding
-   --  to Nam as specified in the aspect Storage_Model_Type. It is an error if
-   --  no operation corresponding to the given name is found.
+   --  to Nam as specified in the aspect Storage_Model_Type. In the case of
+   --  aspect Storage_Model_Type, returns Empty when no operation is found,
+   --  indicating that the operation is defaulted in the aspect (can occur in
+   --  the case where the storage-model address type is System.Address).
 
    function Find_Hook_Context (N : Node_Id) return Node_Id;
    --  Determine a suitable node on which to attach actions related to N that

diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb
index 7ea04a651e7b9cfeecdd4b718234ae609d76bca1..9c3ae6fe33d0da17419e666f6377d2438011b44d 100644 (file)
--- a/gcc/ada/sem_ch13.adb
+++ b/gcc/ada/sem_ch13.adb
@@ -23,59 +23,60 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Aspects;        use Aspects;
-with Atree;          use Atree;
-with Checks;         use Checks;
-with Contracts;      use Contracts;
-with Debug;          use Debug;
-with Einfo;          use Einfo;
-with Einfo.Entities; use Einfo.Entities;
-with Einfo.Utils;    use Einfo.Utils;
-with Elists;         use Elists;
-with Errout;         use Errout;
-with Exp_Ch3;        use Exp_Ch3;
-with Exp_Disp;       use Exp_Disp;
-with Exp_Tss;        use Exp_Tss;
-with Exp_Util;       use Exp_Util;
-with Freeze;         use Freeze;
-with Ghost;          use Ghost;
-with Lib;            use Lib;
-with Lib.Xref;       use Lib.Xref;
-with Namet;          use Namet;
-with Nlists;         use Nlists;
-with Nmake;          use Nmake;
-with Opt;            use Opt;
-with Par_SCO;        use Par_SCO;
-with Restrict;       use Restrict;
-with Rident;         use Rident;
-with Rtsfind;        use Rtsfind;
-with Sem;            use Sem;
-with Sem_Aux;        use Sem_Aux;
-with Sem_Case;       use Sem_Case;
-with Sem_Cat;        use Sem_Cat;
-with Sem_Ch3;        use Sem_Ch3;
-with Sem_Ch6;        use Sem_Ch6;
-with Sem_Ch7;        use Sem_Ch7;
-with Sem_Ch8;        use Sem_Ch8;
-with Sem_Dim;        use Sem_Dim;
-with Sem_Eval;       use Sem_Eval;
-with Sem_Prag;       use Sem_Prag;
-with Sem_Res;        use Sem_Res;
-with Sem_Type;       use Sem_Type;
-with Sem_Util;       use Sem_Util;
-with Sem_Warn;       use Sem_Warn;
-with Sinfo;          use Sinfo;
-with Sinfo.Nodes;    use Sinfo.Nodes;
-with Sinfo.Utils;    use Sinfo.Utils;
-with Sinput;         use Sinput;
-with Snames;         use Snames;
-with Stand;          use Stand;
+with Aspects;          use Aspects;
+with Atree;            use Atree;
+with Checks;           use Checks;
+with Contracts;        use Contracts;
+with Debug;            use Debug;
+with Einfo;            use Einfo;
+with Einfo.Entities;   use Einfo.Entities;
+with Einfo.Utils;      use Einfo.Utils;
+with Elists;           use Elists;
+with Errout;           use Errout;
+with Exp_Ch3;          use Exp_Ch3;
+with Exp_Disp;         use Exp_Disp;
+with Exp_Tss;          use Exp_Tss;
+with Exp_Util;         use Exp_Util;
+with Freeze;           use Freeze;
+with Ghost;            use Ghost;
+with Lib;              use Lib;
+with Lib.Xref;         use Lib.Xref;
+with Namet;            use Namet;
+with Nlists;           use Nlists;
+with Nmake;            use Nmake;
+with Opt;              use Opt;
+with Par_SCO;          use Par_SCO;
+with Restrict;         use Restrict;
+with Rident;           use Rident;
+with Rtsfind;          use Rtsfind;
+with Sem;              use Sem;
+with Sem_Aux;          use Sem_Aux;
+with Sem_Case;         use Sem_Case;
+with Sem_Cat;          use Sem_Cat;
+with Sem_Ch3;          use Sem_Ch3;
+with Sem_Ch6;          use Sem_Ch6;
+with Sem_Ch7;          use Sem_Ch7;
+with Sem_Ch8;          use Sem_Ch8;
+with Sem_Dim;          use Sem_Dim;
+with Sem_Eval;         use Sem_Eval;
+with Sem_Prag;         use Sem_Prag;
+with Sem_Res;          use Sem_Res;
+with Sem_Type;         use Sem_Type;
+with Sem_Util;         use Sem_Util;
+with Sem_Warn;         use Sem_Warn;
+with Sinfo;            use Sinfo;
+with Sinfo.Nodes;      use Sinfo.Nodes;
+with Sinfo.Utils;      use Sinfo.Utils;
+with Sinput;           use Sinput;
+with Snames;           use Snames;
+with Stand;            use Stand;
+with System.Case_Util; use System.Case_Util;
 with Table;
-with Targparm;       use Targparm;
-with Ttypes;         use Ttypes;
-with Tbuild;         use Tbuild;
-with Urealp;         use Urealp;
-with Warnsw;         use Warnsw;
+with Targparm;         use Targparm;
+with Ttypes;           use Ttypes;
+with Tbuild;           use Tbuild;
+with Urealp;           use Urealp;
+with Warnsw;           use Warnsw;
 
 with GNAT.Heap_Sort_G;
 
@@ -11356,6 +11357,16 @@ package body Sem_Ch13 is
             return;
 
          when Aspect_Storage_Model_Type =>
+
+            --  The aggregate argument of Storage_Model_Type is optional, and
+            --  when not present the aspect defaults to the native storage
+            --  model (where the address type is System.Address, and other
+            --  arguments default to corresponding native storage operations).
+
+            if No (Expression (ASN)) then
+               return;
+            end if;
+
             T := Entity (ASN);
 
             declare
@@ -16559,12 +16570,14 @@ package body Sem_Ch13 is
 
          return;
 
+      --  If Addr_Type is not present as the first association, then we default
+      --  it to System.Address.
+
       elsif not Present (Addr_Type) then
-         Error_Msg_N ("argument association for Address_Type missing; "
-                         & "must be specified as first aspect argument", N);
-         return;
+         Addr_Type := RTE (RE_Address);
+      end if;
 
-      elsif Nam = Name_Null_Address then
+      if Nam = Name_Null_Address then
          if not Is_Entity_Name (N)
            or else not Is_Constant_Object (Entity (N))
            or else
@@ -17335,9 +17348,10 @@ package body Sem_Ch13 is
    procedure Validate_Storage_Model_Type_Aspect
      (Typ : Entity_Id; ASN : Node_Id)
    is
-      Assoc  : Node_Id;
-      Choice : Entity_Id;
-      Expr   : Node_Id;
+      Assoc       : Node_Id;
+      Choice      : Entity_Id;
+      Choice_Name : Name_Id;
+      Expr        : Node_Id;
 
       Address_Type_Id : Entity_Id := Empty;
       Null_Address_Id : Entity_Id := Empty;
@@ -17347,7 +17361,47 @@ package body Sem_Ch13 is
       Copy_To_Id      : Entity_Id := Empty;
       Storage_Size_Id : Entity_Id := Empty;
 
+      procedure Check_And_Resolve_Storage_Model_Type_Argument
+        (Expr        : Node_Id;
+         Typ         : Entity_Id;
+         Argument_Id : in out Entity_Id;
+         Nam         : Name_Id);
+      --  Checks that the subaspect for Nam has not already been specified for
+      --  Typ's Storage_Model_Type aspect (i.e., checks Argument_Id = Empty),
+      --  resolves Expr, and sets Argument_Id to the entity resolved for Expr.
+
+      procedure Check_And_Resolve_Storage_Model_Type_Argument
+        (Expr        : Node_Id;
+         Typ         : Entity_Id;
+         Argument_Id : in out Entity_Id;
+         Nam         : Name_Id)
+      is
+         Name_String : constant String := To_Mixed (Get_Name_String (Nam));
+
+      begin
+         if Present (Argument_Id) then
+            Error_Msg_String (1 .. Name_String'Length) := Name_String;
+            Error_Msg_Strlen := Name_String'Length;
+
+            Error_Msg_N ("~ already specified", Expr);
+         end if;
+
+         Resolve_Storage_Model_Type_Argument (Expr, Typ, Address_Type_Id, Nam);
+         Argument_Id := Entity (Expr);
+      end Check_And_Resolve_Storage_Model_Type_Argument;
+
+   --  Start of processing for Validate_Storage_Model_Type_Aspect
+
    begin
+      --  The aggregate argument of Storage_Model_Type is optional, and when
+      --  not present the aspect defaults to the native storage model (where
+      --  the address type is System.Address, and other arguments default to
+      --  the corresponding native storage operations).
+
+      if No (Expression (ASN)) then
+         return;
+      end if;
+
       --  Each expression must resolve to an entity of the right kind or proper
       --  profile.
 
@@ -17358,65 +17412,67 @@ package body Sem_Ch13 is
 
          Choice := First (Choices (Assoc));
 
+         Choice_Name := Chars (Choice);
+
          if Nkind (Choice) /= N_Identifier or else Present (Next (Choice)) then
             Error_Msg_N ("illegal name in association", Choice);
 
-         elsif Chars (Choice) = Name_Address_Type then
+         elsif Choice_Name = Name_Address_Type then
             if Assoc /= First (Component_Associations (Expression (ASN))) then
                Error_Msg_N ("Address_Type must be first association", Choice);
             end if;
 
-            Resolve_Storage_Model_Type_Argument
+            Check_And_Resolve_Storage_Model_Type_Argument
               (Expr, Typ, Address_Type_Id, Name_Address_Type);
-            Address_Type_Id := Entity (Expr);
 
-         --  Shouldn't we check for duplicates of the same subaspect name,
-         --  and issue an error in such cases???
+         else
+            --  It's allowed to leave out the Address_Type argument, in which
+            --  case the address type is defined to default to System.Address.
 
-         elsif not Present (Address_Type_Id) then
-            Error_Msg_N
-              ("Address_Type missing, must be first association", Choice);
-
-         elsif Chars (Choice) = Name_Null_Address then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Null_Address);
-            Null_Address_Id := Entity (Expr);
-
-         elsif Chars (Choice) = Name_Allocate then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Allocate);
-            Allocate_Id := Entity (Expr);
-
-         elsif Chars (Choice) = Name_Deallocate then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Deallocate);
-            Deallocate_Id := Entity (Expr);
-
-         elsif Chars (Choice) = Name_Copy_From then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Copy_From);
-            Copy_From_Id := Entity (Expr);
-
-         elsif Chars (Choice) = Name_Copy_To then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Copy_To);
-            Copy_To_Id := Entity (Expr);
-
-         elsif Chars (Choice) = Name_Storage_Size then
-            Resolve_Storage_Model_Type_Argument
-              (Expr, Typ, Address_Type_Id, Name_Storage_Size);
-            Storage_Size_Id := Entity (Expr);
+            if No (Address_Type_Id) then
+               Address_Type_Id := RTE (RE_Address);
+            end if;
 
-         else
-            Error_Msg_N
-              ("invalid name for Storage_Model_Type argument", Choice);
+            if Choice_Name = Name_Null_Address then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Null_Address_Id, Name_Null_Address);
+
+            elsif Choice_Name = Name_Allocate then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Allocate_Id, Name_Allocate);
+
+            elsif Choice_Name = Name_Deallocate then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Deallocate_Id, Name_Deallocate);
+
+            elsif Choice_Name = Name_Copy_From then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Copy_From_Id, Name_Copy_From);
+
+            elsif Choice_Name = Name_Copy_To then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Copy_To_Id, Name_Copy_To);
+
+            elsif Choice_Name = Name_Storage_Size then
+               Check_And_Resolve_Storage_Model_Type_Argument
+                 (Expr, Typ, Storage_Size_Id, Name_Storage_Size);
+
+            else
+               Error_Msg_N
+                 ("invalid name for Storage_Model_Type argument", Choice);
+            end if;
          end if;
 
          Next (Assoc);
       end loop;
 
-      if No (Address_Type_Id) then
-         Error_Msg_N ("match for Address_Type not found", ASN);
+      --  If Address_Type has been specified as or defaults to System.Address,
+      --  then other "subaspect" arguments can be specified, but are optional.
+      --  Otherwise, all other arguments are required and an error is flagged
+      --  about any that are missing.
+
+      if Address_Type_Id = RTE (RE_Address) then
+         return;
 
       elsif No (Null_Address_Id) then
          Error_Msg_N ("match for Null_Address primitive not found", ASN);

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index 854afdf1170e8e9a76bf6d1e754c7f7d2ee299ee..13ffb11f0a9af8ebd45734b408042582db83b59c 100644 (file)
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -32575,18 +32575,37 @@ package body Sem_Util is
            Find_Value_Of_Aspect (Typ, Aspect_Storage_Model_Type);
 
       begin
-         pragma Assert (Present (SMT_Aspect_Value));
+         --  When the aspect has an aggregate expression, search through it
+         --  to locate a match for the name of the given "subaspect" and return
+         --  the entity of the aggregate association's expression.
+
+         if Present (SMT_Aspect_Value) then
+            Assoc := First (Component_Associations (SMT_Aspect_Value));
+            while Present (Assoc) loop
+               if Chars (First (Choices (Assoc))) = Nam then
+                  return Entity (Expression (Assoc));
+               end if;
 
-         Assoc := First (Component_Associations (SMT_Aspect_Value));
-         while Present (Assoc) loop
-            if Chars (First (Choices (Assoc))) = Nam then
-               return Entity (Expression (Assoc));
-            end if;
+               Next (Assoc);
+            end loop;
+         end if;
 
-            Next (Assoc);
-         end loop;
+         --  The aggregate argument of Storage_Model_Type is optional, and when
+         --  not present the aspect defaults to the native storage model, where
+         --  the address type is System.Address. In that case, we return
+         --  System.Address for Name_Address_Type and System.Null_Address for
+         --  Name_Null_Address, but return Empty for other cases, and leave it
+         --  to the back end to map those to the appropriate native operations.
 
-         return Empty;
+         if Nam = Name_Address_Type then
+            return RTE (RE_Address);
+
+         elsif Nam = Name_Null_Address then
+            return RTE (RE_Null_Address);
+
+         else
+            return Empty;
+         end if;
       end Get_Storage_Model_Type_Entity;
 
       --------------------------------

diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
index 64cf5d041dd74db06815c8e50f3300379739e858..dde5b27faa33bac9758d6961826bc943c41179e0 100644 (file)
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -3680,21 +3680,26 @@ package Sem_Util is
       --  Given a type with aspect Storage_Model_Type or an object of such a
       --  type, and Nam denoting the name of one of the argument kinds allowed
       --  for that aspect, returns the Entity_Id corresponding to the entity
-      --  associated with Nam in the aspect. If such an entity is not present,
-      --  then returns Empty. (Note: This function is modeled on function
-      --  Get_Iterable_Type_Primitive.)
+      --  associated with Nam in the aspect. If an entity was not explicitly
+      --  specified for Nam, then returns Empty, except that in the defaulted
+      --  Address_Type case, System.Address will be returned, and in the
+      --  defaulted Null_Address case, System.Null_Address will be returned.
+      --  (Note: This function is modeled on Get_Iterable_Type_Primitive.)
 
       function Storage_Model_Address_Type
         (SM_Obj_Or_Type : Entity_Id) return Entity_Id;
       --  Given a type with aspect Storage_Model_Type or an object of such a
       --  type, returns the type specified for the Address_Type choice in that
-      --  aspect; returns Empty if the type isn't specified.
+      --  aspect; returns type System.Address if the address type was not
+      --  explicitly specified (indicating use of the native memory model).
 
       function Storage_Model_Null_Address
         (SM_Obj_Or_Type : Entity_Id) return Entity_Id;
       --  Given a type with aspect Storage_Model_Type or an object of such a
       --  type, returns the constant specified for the Null_Address choice in
-      --  that aspect; returns Empty if the constant object isn't specified.
+      --  that aspect; returns Empty if the constant object isn't specified,
+      --  unless the native memory model is in use (System.Address), in which
+      --  case it returns System.Null_Address.
 
       function Storage_Model_Allocate
         (SM_Obj_Or_Type : Entity_Id) return Entity_Id;