From: Clemens Fruhwirth <clemens@endorphin.org>
Date: Fri, 13 Jul 2007 21:08:45 +0000 (+0000)
Subject: Add import facility to cmm parser
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=d55027c917a101692ded11b6b1421052866df2d4

Add import facility to cmm parser

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.
---

diff --git a/compiler/cmm/CmmParse.y b/compiler/cmm/CmmParse.y
index fa822f6..579df5e 100644
--- a/compiler/cmm/CmmParse.y
+++ b/compiler/cmm/CmmParse.y
@@ -294,7 +294,7 @@ decl	:: { ExtCode }
 	| 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] }
@@ -793,6 +793,13 @@ newLocal kind ty name = do
    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