* s-rident.ads: Add new restriction No_Implicit_Aliasing
* sem_attr.adb: (Analyze_Access_Attribute): Deal with
No_Implicit_Aliasing
(Analyze_Attribute, case Address): ditto
(Analyze_Attribute, case Unrestricted_Access): ditto
* sem_util.ads, sem_util.adb: (Is_Aliased_View): Handle
No_Implicit_Aliasing restriction.
* gnat_rm.texi: Add documentation for No_Implicit_Aliasing
2011-09-02 Ed Schonberg <schonberg@adacore.com>
* exp_util.adb: (Possible_Bit_Aligned_Object): If the object
is an unchecked conversion, apply test to its expression.
2011-09-02 Javier Miranda <miranda@adacore.com>
* sem_ch3.adb (Check_Abstract_Overriding): When
traversing the chain of aliased subprograms avoid reporting a
redundant error on the current entity.
2011-09-02 Sergey Rybin <rybin@adacore.com>
* gnat_ugn.texi: Minor clean up.
2011-09-02 Bob Duff <duff@adacore.com>
* s-htable.adb (Set_If_Not_Present): Use renaming
instead of ":=", because the type Key is limited in the generic (even
if not in the instances).
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@178440
138bc75d-0d04-0410-961f-
82ee72b054a4
2011-09-02 Robert Dewar <dewar@adacore.com>
+ * s-rident.ads: Add new restriction No_Implicit_Aliasing
+ * sem_attr.adb: (Analyze_Access_Attribute): Deal with
+ No_Implicit_Aliasing
+ (Analyze_Attribute, case Address): ditto
+ (Analyze_Attribute, case Unrestricted_Access): ditto
+ * sem_util.ads, sem_util.adb: (Is_Aliased_View): Handle
+ No_Implicit_Aliasing restriction.
+ * gnat_rm.texi: Add documentation for No_Implicit_Aliasing
+
+2011-09-02 Ed Schonberg <schonberg@adacore.com>
+
+ * exp_util.adb: (Possible_Bit_Aligned_Object): If the object
+ is an unchecked conversion, apply test to its expression.
+
+2011-09-02 Javier Miranda <miranda@adacore.com>
+
+ * sem_ch3.adb (Check_Abstract_Overriding): When
+ traversing the chain of aliased subprograms avoid reporting a
+ redundant error on the current entity.
+
+2011-09-02 Sergey Rybin <rybin@adacore.com>
+
+ * gnat_ugn.texi: Minor clean up.
+
+2011-09-02 Bob Duff <duff@adacore.com>
+
+ * s-htable.adb (Set_If_Not_Present): Use renaming
+ instead of ":=", because the type Key is limited in the generic (even
+ if not in the instances).
+
+2011-09-02 Robert Dewar <dewar@adacore.com>
+
* exp_util.adb, sem_ch10.adb, sem_attr.adb, s-htable.adb,
g-comlin.adb, g-comlin.ads, lib-xref-alfa.adb, lib-xref.adb: Minor
reformatting.
when N_Slice =>
return Possible_Bit_Aligned_Component (Prefix (N));
+ -- For an unchecked conversion, check whether the expression may
+ -- be bit-aligned.
+
+ when N_Unchecked_Type_Conversion =>
+ return Possible_Bit_Aligned_Component (Expression (N));
+
-- If we have none of the above, it means that we have fallen off the
-- top testing prefixes recursively, and we now have a stand alone
-- object, where we don't have a problem.
code is simplified by omitting the otherwise-required global registration
of exceptions when they are declared.
+@item No_Implicit_Aliasing
+@findex No_Implicit_Aliasing
+
+This restriction, which is not required to be partition-wide consistent,
+requires an explicit aliased keyword for an object to which 'Access,
+'Unchecked_Access, or 'Address is applied, and forbids entirely the use of
+the 'Unrestricted_Access attribute for objects. Note: the reason that
+Unrestricted_Access is forbidden is that it would require the prefix
+to be aliased, and in such cases, it can always be replaced by
+the standard attribute Unchecked_Access which is preferable.
+
@item No_Implicit_Conditionals
@findex No_Implicit_Conditionals
This restriction ensures that the generated code does not contain any
@item ^-c5^/COMMENTS_LAYOUT=KEEP_SPECIAL^
Keep unchanged special form comments
-Reformat comment blocks
-
@cindex @option{^-l@var{n}^/CONSTRUCT_LAYOUT^} (@command{gnatpp})
@item ^-l1^/CONSTRUCT_LAYOUT=GNAT^
GNAT-style layout (this is the default)
------------------------
function Set_If_Not_Present (E : Elmt_Ptr) return Boolean is
- K : constant Key := Get_Key (E);
+ K : Key renames Get_Key (E);
+ -- Note that it is important to use a renaming here rather than
+ -- define a constant initialized by the call, because the latter
+ -- construct runs into bootstrap problems with earlier versions
+ -- of the GNAT compiler.
+
Index : constant Header_Num := Hash (K);
Elmt : Elmt_Ptr;
-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
No_Implementation_Attributes, -- Ada 2005 AI-257
No_Implementation_Pragmas, -- Ada 2005 AI-257
No_Implementation_Restrictions, -- GNAT
+ No_Implicit_Aliasing, -- GNAT
No_Elaboration_Code, -- GNAT
No_Obsolescent_Features, -- Ada 2005 AI-368
No_Wide_Characters, -- GNAT
and then not In_Instance
and then not In_Inlined_Body
then
- Error_Attr_P ("prefix of % attribute must be aliased");
+ if Restriction_Check_Required (No_Implicit_Aliasing) then
+ Error_Attr_P
+ ("prefix of % attribute must be explicitly aliased");
+ else
+ Error_Attr_P
+ ("prefix of % attribute must be aliased");
+ end if;
end if;
end Analyze_Access_Attribute;
then
Set_Address_Taken (Ent);
- -- If we have an address of an object, and the attribute
- -- comes from source, then set the object as potentially
- -- source modified. We do this because the resulting address
- -- can potentially be used to modify the variable and we
- -- might not detect this, leading to some junk warnings.
+ -- Deal with No_Implicit_Aliasing restriction
+
+ if Restriction_Check_Required (No_Implicit_Aliasing) then
+ if not Is_Aliased_View (P) then
+ Check_Restriction (No_Implicit_Aliasing, P);
+ end if;
+ end if;
+
+ -- If we have an address of an object, and the attribute
+ -- comes from source, then set the object as potentially
+ -- source modified. We do this because the resulting address
+ -- can potentially be used to modify the variable and we
+ -- might not detect this, leading to some junk warnings.
Set_Never_Set_In_Source (Ent, False);
when Attribute_Unrestricted_Access =>
if Comes_From_Source (N) then
Check_Restriction (No_Unchecked_Access, N);
+
+ if Nkind (P) in N_Has_Entity and then Is_Object (Entity (P)) then
+ Check_Restriction (No_Implicit_Aliasing, N);
+ end if;
end if;
if Is_Entity_Name (P) then
begin
E := Subp;
while Present (Alias (E)) loop
- Error_Msg_Sloc := Sloc (E);
- Error_Msg_NE
- ("\& has been inherited #", T, Subp);
+
+ -- Avoid reporting redundant errors on entities
+ -- inherited from interfaces
+
+ if Sloc (E) /= Sloc (T) then
+ Error_Msg_Sloc := Sloc (E);
+ Error_Msg_NE
+ ("\& has been inherited #", T, Subp);
+ end if;
+
E := Alias (E);
end loop;
begin
if Is_Entity_Name (Obj) then
-
E := Entity (Obj);
+ if Is_Object (E) and then not Is_Aliased (E) then
+ Check_Restriction (No_Implicit_Aliasing, Obj);
+ end if;
+
return
(Is_Object (E)
and then
return Has_Aliased_Components (Etype (Prefix (Obj)))
or else
(Is_Access_Type (Etype (Prefix (Obj)))
- and then
- Has_Aliased_Components
- (Designated_Type (Etype (Prefix (Obj)))));
+ and then Has_Aliased_Components
+ (Designated_Type (Etype (Prefix (Obj)))));
- elsif Nkind (Obj) = N_Unchecked_Type_Conversion
- or else Nkind (Obj) = N_Type_Conversion
- then
+ elsif Nkind_In (Obj, N_Unchecked_Type_Conversion, N_Type_Conversion) then
return Is_Tagged_Type (Etype (Obj))
and then Is_Aliased_View (Expression (Obj));
function Is_Aliased_View (Obj : Node_Id) return Boolean;
-- Determine if Obj is an aliased view, i.e. the name of an object to which
- -- 'Access or 'Unchecked_Access can apply.
+ -- 'Access or 'Unchecked_Access can apply. Note that the implementation
+ -- takes the No_Implicit_Aiasing restriction into account.
function Is_Ancestor_Package
(E1 : Entity_Id;
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