From 71747dda9d491b8b28df20eaed84c71ca75f51d0 Mon Sep 17 00:00:00 2001 From: Steve Baird Date: Fri, 12 Aug 2022 17:04:38 -0700 Subject: [Ada] Enable lock free protected implementation by default In the past, the Lock_Free aspect of a protected type (including an anonymous type) defaulted to False. In the case where an explicit "Lock_Free => True" aspect specification would be legal, the aspect now defaults to True (which means that a lock-free implementation is used to implement the type's protected operations); this is like the previous behavior of the compiler with the -gnatd9 switch specified. Support for the Lock_Free attribute (which should not be confused with the Lock_Free aspect) is removed. gcc/ada/ * debug.adb: Remove comment regarding the -gnatd9 switch. * doc/gnat_rm/implementation_defined_attributes.rst: Remove all mention of the Lock_Free attribute. * gnat_rm.texi, gnat_ugn.texi: Regenerate. * exp_attr.adb, sem_attr.adb: Remove all mention of the former Attribute_Lock_Free enumeration element of the Attribute_Id type. * sem_ch9.adb (Allows_Lock_Free_Implementation): Remove the Debug_Flag_9 test. Return False in the case of a protected function whose result type requires use of the secondary stack. (Satisfies_Lock_Free_Requirements): This functions checks for certain constructs and returns False if one is found. In the case of a protected function, there is no need to check to see if the protected object is being modified. So it is ok to omit *some* checks in the case of a protected function. But other checks which are required (e.g., the test for a reference to a variable that is not part of the protected object) were being incorrectly omitted. This could result in accepting "Lock_Free => True" aspect specifications that should be rejected. * snames.adb-tmpl: Name_Lock_Free no longer requires special treatment in Get_Pragma_Id or Is_Pragma_Name (because it is no longer an attribute name). * snames.ads-tmpl: Move the declaration of Name_Lock_Free to reflect the fact that it is no longer the name of an attribute. Delete Attribute_Lock_Free from the Attribute_Id enumeration type. --- gcc/ada/sem_attr.adb | 44 +------------------------------------------- 1 file changed, 1 insertion(+), 43 deletions(-) (limited to 'gcc/ada/sem_attr.adb') diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb index 93bb6f4..86c7d0f 100644 --- a/gcc/ada/sem_attr.adb +++ b/gcc/ada/sem_attr.adb @@ -4697,19 +4697,6 @@ package body Sem_Attr is Set_Etype (N, Standard_Boolean); - --------------- - -- Lock_Free -- - --------------- - - when Attribute_Lock_Free => - Check_E0; - Set_Etype (N, Standard_Boolean); - - if not Is_Protected_Type (P_Type) then - Error_Attr_P - ("prefix of % attribute must be a protected object"); - end if; - ---------------- -- Loop_Entry -- ---------------- @@ -8338,15 +8325,6 @@ package body Sem_Attr is return; - -- For Lock_Free, we apply the attribute to the type of the object. - -- This is allowed since we have already verified that the type is a - -- protected type. - - elsif Id = Attribute_Lock_Free then - P_Entity := Etype (P); - - -- No other attributes for objects are folded - else Check_Expressions; return; @@ -8476,7 +8454,6 @@ package body Sem_Attr is Id = Attribute_Has_Access_Values or else Id = Attribute_Has_Discriminants or else Id = Attribute_Has_Tagged_Values or else - Id = Attribute_Lock_Free or else Id = Attribute_Preelaborable_Initialization or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array or else @@ -8595,7 +8572,7 @@ package body Sem_Attr is -- only the First, Last and Length attributes are possibly static. -- Atomic_Always_Lock_Free, Definite, Descriptor_Size, Has_Access_Values - -- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and + -- Has_Discriminants, Has_Tagged_Values, Type_Class, and -- Unconstrained_Array are again exceptions, because they apply as well -- to unconstrained types. @@ -8614,7 +8591,6 @@ package body Sem_Attr is Id = Attribute_Has_Access_Values or else Id = Attribute_Has_Discriminants or else Id = Attribute_Has_Tagged_Values or else - Id = Attribute_Lock_Free or else Id = Attribute_Preelaborable_Initialization or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array or else @@ -9315,24 +9291,6 @@ package body Sem_Attr is True); end if; - --------------- - -- Lock_Free -- - --------------- - - when Attribute_Lock_Free => Lock_Free : declare - V : constant Entity_Id := Boolean_Literals (Uses_Lock_Free (P_Type)); - - begin - Rewrite (N, New_Occurrence_Of (V, Loc)); - - -- Analyze and resolve as boolean. Note that this attribute is a - -- static attribute in GNAT. - - Analyze_And_Resolve (N, Standard_Boolean); - Static := True; - Set_Is_Static_Expression (N); - end Lock_Free; - ---------- -- Last -- ---------- -- cgit v1.1