The cmm parser classified all unknown variables as imported. This
behaviour is not changed with this patch. Explicitly imported
variables get a different internal label type, namely ForeignLabel
instead of RtsLabel. In PIC compilation, the NCG creates dynamic
access for ForeignLabel, while RtsLabel are not treated as PIC when
-package rts. Hence, putting explicit imports into cmm files enables
the NCG to distinguish between RTS-external and RTS-internal symbols,
and create the appropriate code.
| STRING type names ';' {% do k <- parseKind $1;
return $ mapM_ (newLocal k $2) $3 }
- | 'import' names ';' { return () } -- ignore imports
+ | 'import' names ';' { mapM_ newImport $2 }
| 'export' names ';' { return () } -- ignore exports
names :: { [FastString] }
addVarDecl name (CmmReg (CmmLocal reg))
return reg
+-- Creates a foreign label in the import. CLabel's labelDynamic
+-- classifies these labels as dynamic, hence the code generator emits the
+-- PIC code for them.
+newImport :: FastString -> ExtFCode ()
+newImport name =
+ addVarDecl name (CmmLit (CmmLabel (mkForeignLabel name Nothing True)))
+
newLabel :: FastString -> ExtFCode BlockId
newLabel name = do
u <- code newUnique