This patch improves the performance of the parser for declarations
ended by a semicolon. Previously an error check for aspect specs
following the semicolon was done inefficiently.
There should be no external effect from this improvement. But the
following test is useful:
1. pragma Ada_2012;
2. package AspectSem is
3. type R is new Integer;
|
>>> extra ";" ignored
4. with Size => 64;
5. end;
This gives the same output befor and after the patch, but the internal
mechanism for giving that message is entirely different.
Tested on x86_64-pc-linux-gnu, committed on trunk
2011-08-02 Robert Dewar <de...@adacore.com>
* par-ch13.adb (Aspect_Specifications_Present): Always return false on
semicolon, do not try to see if there are aspects following it.
* par-ch3.adb (P_Declarative_Items): Better message for unexpected
aspect spec.
Index: par-ch13.adb
===================================================================
--- par-ch13.adb (revision 177086)
+++ par-ch13.adb (working copy)
@@ -46,31 +46,19 @@
Result : Boolean;
begin
- Save_Scan_State (Scan_State);
+ -- Definitely must have WITH to consider aspect specs to be present
- -- If we have a semicolon, test for semicolon followed by Aspect
- -- Specifications, in which case we decide the semicolon is accidental.
+ -- Note that this means that if we have a semicolon, we immediately
+ -- return False. There is a case in which this is not optimal, namely
+ -- something like
- if Token = Tok_Semicolon then
- Scan; -- past semicolon
+ -- type R is new Integer;
+ -- with bla bla;
- -- The recursive test is set Strict, since we already have one
- -- error (the unexpected semicolon), so we will ignore that semicolon
- -- only if we absolutely definitely have an aspect specification
- -- following it.
+ -- where the semicolon is redundant, but scanning forward for it would
+ -- be too expensive. Instead we pick up the aspect specifications later
+ -- as a bogus declaration, and diagnose the semicolon at that point.
- if Aspect_Specifications_Present (Strict => True) then
- Error_Msg_SP ("|extra "";"" ignored");
- return True;
-
- else
- Restore_Scan_State (Scan_State);
- return False;
- end if;
- end if;
-
- -- Definitely must have WITH to consider aspect specs to be present
-
if Token /= Tok_With then
return False;
end if;
Index: par-ch3.adb
===================================================================
--- par-ch3.adb (revision 177029)
+++ par-ch3.adb (working copy)
@@ -4274,9 +4274,43 @@
when Tok_With =>
Check_Bad_Layout;
- Error_Msg_SC ("WITH can only appear in context clause");
- raise Error_Resync;
+ if Aspect_Specifications_Present then
+
+ -- If we are after a semicolon, complain that it was ignored.
+ -- But we don't really ignore it, since we dump the aspects,
+ -- so we make the error message a normal fatal message which
+ -- will inhibit semantic analysis anyway).
+
+ if Prev_Token = Tok_Semicolon then
+ Error_Msg_SP -- CODEFIX
+ ("extra "";"" ignored");
+
+ -- If not just past semicolon, just complain that aspects are
+ -- not allowed at this point.
+
+ else
+ Error_Msg_SC ("aspect specifications not allowed here");
+ end if;
+
+ declare
+ Dummy_Node : constant Node_Id :=
+ New_Node (N_Package_Specification, Token_Ptr);
+ pragma Warnings (Off, Dummy_Node);
+ -- Dummy node to attach aspect specifications to. We will
+ -- then throw them away.
+
+ begin
+ P_Aspect_Specifications (Dummy_Node, Semicolon => True);
+ end;
+
+ -- Here if not aspect specifications case
+
+ else
+ Error_Msg_SC ("WITH can only appear in context clause");
+ raise Error_Resync;
+ end if;
+
-- BEGIN terminates the scan of a sequence of declarations unless
-- there is a missing subprogram body, see section on handling
-- semicolon in place of IS. We only treat the begin as satisfying
