llvmGen: Make metadata ids a newtype

These were previously just represented as Ints which was needlessly
vague.

2 files changed, 18 insertions, 10 deletions

diff --git a/compiler/llvmGen/Llvm/MetaData.hs b/compiler/llvmGen/Llvm/MetaData.hs
index e1e63c9191..a50553ccb0 100644
--- a/compiler/llvmGen/Llvm/MetaData.hs
+++ b/compiler/llvmGen/Llvm/MetaData.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+
 module Llvm.MetaData where
 
 import Llvm.Types
@@ -55,16 +57,23 @@ import Outputable
 --     !llvm.module.linkage = !{ !0, !1 }
 --
 
+-- | A reference to an un-named metadata node.
+newtype MetaId = MetaId Int
+               deriving (Eq, Ord, Enum)
+
+instance Outputable MetaId where
+    ppr (MetaId n) = char '!' <> int n
+
 -- | LLVM metadata expressions
 data MetaExpr = MetaStr LMString
-              | MetaNode Int
+              | MetaNode MetaId
               | MetaVar LlvmVar
               | MetaStruct [MetaExpr]
               deriving (Eq)
 
 instance Outputable MetaExpr where
   ppr (MetaStr    s ) = text "!\"" <> ftext s <> char '"'
-  ppr (MetaNode   n ) = text "!" <> int n
+  ppr (MetaNode   n ) = ppr n
   ppr (MetaVar    v ) = ppr v
   ppr (MetaStruct es) = text "!{ " <> ppCommaJoin es <> char '}'
 
@@ -77,7 +86,7 @@ data MetaAnnot = MetaAnnot LMString MetaExpr
 data MetaDecl
     -- | Named metadata. Only used for communicating module information to
     -- LLVM. ('!name = !{ [!<n>] }' form).
-    = MetaNamed LMString [Int]
+    = MetaNamed LMString [MetaId]
     -- | Metadata node declaration.
     -- ('!0 = metadata !{ <metadata expression> }' form).
-    | MetaUnamed Int MetaExpr
+    | MetaUnnamed MetaId MetaExpr
diff --git a/compiler/llvmGen/Llvm/PpLlvm.hs b/compiler/llvmGen/Llvm/PpLlvm.hs
index cdaf962c4a..d92e3c0739 100644
--- a/compiler/llvmGen/Llvm/PpLlvm.hs
+++ b/compiler/llvmGen/Llvm/PpLlvm.hs
@@ -106,20 +106,19 @@ ppLlvmMetas metas = vcat $ map ppLlvmMeta metas
 
 -- | Print out an LLVM metadata definition.
 ppLlvmMeta :: MetaDecl -> SDoc
-ppLlvmMeta (MetaUnamed n m)
-  = exclamation <> int n <> text " = " <> ppLlvmMetaExpr m
+ppLlvmMeta (MetaUnnamed n m)
+  = ppr n <> text " = " <> ppLlvmMetaExpr m
 
 ppLlvmMeta (MetaNamed n m)
   = exclamation <> ftext n <> text " = !" <> braces nodes
   where
-    nodes = hcat $ intersperse comma $ map pprNode m
-    pprNode n = exclamation <> int n
+    nodes = hcat $ intersperse comma $ map ppr m
 
 -- | Print out an LLVM metadata value.
 ppLlvmMetaExpr :: MetaExpr -> SDoc
 ppLlvmMetaExpr (MetaVar (LMLitVar (LMNullLit _))) = text "null"
 ppLlvmMetaExpr (MetaStr    s ) = text "!" <> doubleQuotes (ftext s)
-ppLlvmMetaExpr (MetaNode   n ) = text "!" <> int n
+ppLlvmMetaExpr (MetaNode   n ) = ppr n
 ppLlvmMetaExpr (MetaVar    v ) = ppr v
 ppLlvmMetaExpr (MetaStruct es) =
     text "!{" <> hsep (punctuate comma (map ppLlvmMetaExpr es)) <> char '}'
@@ -489,7 +488,7 @@ ppMetaAnnots meta = hcat $ map ppMeta meta
     ppMeta (MetaAnnot name e)
         = comma <+> exclamation <> ftext name <+>
           case e of
-            MetaNode n    -> exclamation <> int n
+            MetaNode n    -> ppr n
             MetaStruct ms -> exclamation <> braces (ppCommaJoin ms)
             other         -> exclamation <> braces (ppr other) -- possible?