Declare some top level globals to be constant when appropriate

This involved removing the old constant handling mechanism
which was fairly hard to use. Now being constant or not is
simply a property of a global variable instead of a separate
type.

1 files changed, 19 insertions, 6 deletions

diff --git a/compiler/llvmGen/LlvmCodeGen/Data.hs b/compiler/llvmGen/LlvmCodeGen/Data.hs
index 13da03b840..3cf6cdac85 100644
--- a/compiler/llvmGen/LlvmCodeGen/Data.hs
+++ b/compiler/llvmGen/LlvmCodeGen/Data.hs
@@ -37,8 +37,8 @@ structStr = fsLit "_struct"
 -- complete this completely though as we need to pass all CmmStatic
 -- sections before all references can be resolved. This last step is
 -- done by 'resolveLlvmData'.
-genLlvmData :: [CmmStatic] -> LlvmUnresData
-genLlvmData (CmmDataLabel lbl:xs) =
+genLlvmData :: (Section, [CmmStatic]) -> LlvmUnresData
+genLlvmData (sec, CmmDataLabel lbl:xs) =
     let static  = map genData xs
         label   = strCLabel_llvm lbl
 
@@ -48,10 +48,11 @@ genLlvmData (CmmDataLabel lbl:xs) =
 
         strucTy = LMStruct types
         alias   = LMAlias (label `appendFS` structStr) strucTy
-    in (lbl, alias, static)
+    in (lbl, sec, alias, static)
 
 genLlvmData _ = panic "genLlvmData: CmmData section doesn't start with label!"
 
+
 resolveLlvmDatas ::  LlvmEnv -> [LlvmUnresData] -> [LlvmData]
                  -> (LlvmEnv, [LlvmData])
 resolveLlvmDatas env [] ldata
@@ -63,17 +64,29 @@ resolveLlvmDatas env (udata : rest) ldata
 
 -- | Fix up CLabel references now that we should have passed all CmmData.
 resolveLlvmData :: LlvmEnv -> LlvmUnresData -> (LlvmEnv, LlvmData)
-resolveLlvmData env (lbl, alias, unres) =
+resolveLlvmData env (lbl, sec, alias, unres) =
     let (env', static, refs) = resDatas env unres ([], [])
         refs'          = catMaybes refs
         struct         = Just $ LMStaticStruc static alias
         label          = strCLabel_llvm lbl
         link           = if (externallyVisibleCLabel lbl)
                             then ExternallyVisible else Internal
-        glob           = LMGlobalVar label alias link Nothing Nothing
+        const          = isSecConstant sec
+        glob           = LMGlobalVar label alias link Nothing Nothing const
     in (env', (refs' ++ [(glob, struct)], [alias]))
 
 
+-- | Should a data in this section be considered constant
+isSecConstant :: Section -> Bool
+isSecConstant Text                    = True
+isSecConstant Data                    = False
+isSecConstant ReadOnlyData            = True
+isSecConstant RelocatableReadOnlyData = True
+isSecConstant UninitialisedData       = False
+isSecConstant ReadOnlyData16          = True
+isSecConstant (OtherSection _)        = False
+
+
 -- ----------------------------------------------------------------------------
 -- ** Resolve Data/CLabel references
 --
@@ -114,7 +127,7 @@ resData env (Left cmm@(CmmLabel l)) =
             -- pointer to it.
             Just ty' ->
                 let var = LMGlobalVar label (LMPointer ty')
-                            ExternallyVisible Nothing Nothing
+                            ExternallyVisible Nothing Nothing False
                     ptr  = LMStaticPointer var
                 in (env, LMPtoI ptr lmty, [Nothing])