This is useful in particular to be able to mark a formal parameter of an
expression function as unreferenced:
function F (Param : Integer with Unreferenced) return Integer is (1);
We also add the infrastructure to support other aspects on formal
parameters in the future.
Put this feature under -gnatX for now since the Ada RM doesn't support
this syntax (yet).
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* aspects.adb (Has_Aspect_Specifications_Flag): Add
N_Parameter_Specification.
* par-ch13.adb (Aspect_Specifications_Present): Also handle case
of an unknown aspect on the last formal parameter (terminated by
a Tok_Right_Paren). Minor reformatting.
* par-ch6.adb (P_Formal_Part): Scan aspects on formal
parameters.
* par.adb: Fix typos.
* sem_ch6.adb (Process_Formals): Add processing of aspects and
in particular Unreferenced aspect for now.
* sinfo.ads: Allow ASPECT_SPECIFICATIONS on a
PARAMETER_SPECIFICATION.
* doc/gnat_rm/implementation_defined_aspects.rst
(Aspect Unreferenced): Update documentation.
* gnat_rm.texi: Regenerate.diff --git a/gcc/ada/aspects.adb b/gcc/ada/aspects.adb
--- a/gcc/ada/aspects.adb
+++ b/gcc/ada/aspects.adb
@@ -455,6 +455,7 @@ package body Aspects is
N_Package_Instantiation => True,
N_Package_Specification => True,
N_Package_Renaming_Declaration => True,
+ N_Parameter_Specification => True,
N_Private_Extension_Declaration => True,
N_Private_Type_Declaration => True,
N_Procedure_Instantiation => True,
diff --git a/gcc/ada/doc/gnat_rm/implementation_defined_aspects.rst b/gcc/ada/doc/gnat_rm/implementation_defined_aspects.rst
--- a/gcc/ada/doc/gnat_rm/implementation_defined_aspects.rst
+++ b/gcc/ada/doc/gnat_rm/implementation_defined_aspects.rst
@@ -564,9 +564,11 @@ Aspect Unreferenced
===================
.. index:: Unreferenced
-This boolean aspect is equivalent to :ref:`pragma Unreferenced<Pragma-Unreferenced>`. Note that
-in the case of formal parameters, it is not permitted to have aspects for
-a formal parameter, so in this case the pragma form must be used.
+This boolean aspect is equivalent to :ref:`pragma Unreferenced<Pragma-Unreferenced>`.
+
+When using the ``-gnatX`` switch, this aspect is also supported on formal
+parameters, which is in particular the only form possible for expression
+functions.
Aspect Unreferenced_Objects
===========================
diff --git a/gcc/ada/gnat_rm.texi b/gcc/ada/gnat_rm.texi
--- a/gcc/ada/gnat_rm.texi
+++ b/gcc/ada/gnat_rm.texi
@@ -9923,9 +9923,11 @@ This boolean aspect is equivalent to @ref{10b,,pragma Unmodified}.
@geindex Unreferenced
-This boolean aspect is equivalent to @ref{10c,,pragma Unreferenced}. Note that
-in the case of formal parameters, it is not permitted to have aspects for
-a formal parameter, so in this case the pragma form must be used.
+This boolean aspect is equivalent to @ref{10c,,pragma Unreferenced}.
+
+When using the @code{-gnatX} switch, this aspect is also supported on formal
+parameters, which is in particular the only form possible for expression
+functions.
@node Aspect Unreferenced_Objects,Aspect Value_Size,Aspect Unreferenced,Implementation Defined Aspects
@anchor{gnat_rm/implementation_defined_aspects aspect-unreferenced-objects}@anchor{15e}
diff --git a/gcc/ada/par-ch13.adb b/gcc/ada/par-ch13.adb
--- a/gcc/ada/par-ch13.adb
+++ b/gcc/ada/par-ch13.adb
@@ -153,7 +153,8 @@ package body Ch13 is
Result := True;
else
Scan; -- past identifier
- Result := Token in Tok_Arrow | Tok_Comma | Tok_Is | Tok_Semicolon;
+ Result := Token in
+ Tok_Arrow | Tok_Comma | Tok_Is | Tok_Semicolon | Tok_Right_Paren;
end if;
-- If earlier than Ada 2012, check for valid aspect identifier (possibly
@@ -956,7 +957,7 @@ package body Ch13 is
-- If Decl is Error, we ignore the aspects, and issue a message
elsif Decl = Error
- or else not Permits_Aspect_Specifications (Decl)
+ or else not Permits_Aspect_Specifications (Decl)
then
Error_Msg ("aspect specifications not allowed here", Ptr);
diff --git a/gcc/ada/par-ch6.adb b/gcc/ada/par-ch6.adb
--- a/gcc/ada/par-ch6.adb
+++ b/gcc/ada/par-ch6.adb
@@ -1627,6 +1627,25 @@ package body Ch6 is
Scan; -- past right paren
exit Specification_Loop;
+ -- Support for aspects on formal parameters is a GNAT extension for
+ -- the time being.
+
+ elsif Token = Tok_With then
+ if not Extensions_Allowed then
+ Error_Msg_SP ("aspect on formal parameter requires -gnatX");
+ end if;
+
+ P_Aspect_Specifications (Specification_Node, False);
+
+ if Token = Tok_Right_Paren then
+ Scan; -- past right paren
+ exit Specification_Loop;
+
+ elsif Token = Tok_Semicolon then
+ Save_Scan_State (Scan_State);
+ Scan; -- past semicolon
+ end if;
+
-- Special check for common error of using comma instead of semicolon
elsif Token = Tok_Comma then
diff --git a/gcc/ada/par.adb b/gcc/ada/par.adb
--- a/gcc/ada/par.adb
+++ b/gcc/ada/par.adb
@@ -995,10 +995,10 @@ function Par (Configuration_Pragmas : Boolean) return List_Id is
procedure P_Aspect_Specifications
(Decl : Node_Id;
Semicolon : Boolean := True);
- -- This procedure scans out a series of aspect spefications. If argument
- -- Semicolon is True, a terminating semicolon is also scanned. If this
- -- argument is False, the scan pointer is left pointing past the aspects
- -- and the caller must check for a proper terminator.
+ -- This procedure scans out a series of aspect specifications. If
+ -- argument Semicolon is True, a terminating semicolon is also scanned.
+ -- If this argument is False, the scan pointer is left pointing past the
+ -- aspects and the caller must check for a proper terminator.
--
-- P_Aspect_Specifications is called with the current token pointing
-- to either a WITH keyword starting an aspect specification, or an
diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -672,9 +672,9 @@ package body Sem_Ch6 is
end if;
end Analyze_Expression_Function;
- ----------------------------------------
- -- Analyze_Extended_Return_Statement --
- ----------------------------------------
+ ---------------------------------------
+ -- Analyze_Extended_Return_Statement --
+ ---------------------------------------
procedure Analyze_Extended_Return_Statement (N : Node_Id) is
begin
@@ -12282,6 +12282,27 @@ package body Sem_Ch6 is
end if;
end if;
+ -- Deal with aspects on formal parameters. Only Unreferenced is
+ -- supported for the time being.
+
+ if Has_Aspects (Param_Spec) then
+ declare
+ Aspect : Node_Id := First (Aspect_Specifications (Param_Spec));
+ begin
+ while Present (Aspect) loop
+ if Chars (Identifier (Aspect)) = Name_Unreferenced then
+ Set_Has_Pragma_Unreferenced (Formal);
+ else
+ Error_Msg_NE
+ ("unsupported aspect& on parameter",
+ Aspect, Identifier (Aspect));
+ end if;
+
+ Next (Aspect);
+ end loop;
+ end;
+ end if;
+
<<Continue>>
Next (Param_Spec);
end loop;
diff --git a/gcc/ada/sinfo.ads b/gcc/ada/sinfo.ads
--- a/gcc/ada/sinfo.ads
+++ b/gcc/ada/sinfo.ads
@@ -5414,9 +5414,9 @@ package Sinfo is
-- PARAMETER_SPECIFICATION ::=
-- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
- -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
+ -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION] [ASPECT_SPECIFICATIONS]
-- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
- -- [:= DEFAULT_EXPRESSION]
+ -- [:= DEFAULT_EXPRESSION] [ASPECT_SPECIFICATIONS]
-- Although the syntax allows multiple identifiers in the list, the
-- semantics is as though successive specifications were given with
