llvmGen/Llvm/PpLlvm.hs

    {-# LANGUAGE CPP #-}

    --------------------------------------------------------------------------------
    -- | Pretty print LLVM IR Code.
    --

    module Llvm.PpLlvm (

        -- * Top level LLVM objects.
        ppLlvmModule,
        ppLlvmComments,
        ppLlvmComment,
        ppLlvmGlobals,
        ppLlvmGlobal,
        ppLlvmAliases,
        ppLlvmAlias,
        ppLlvmMetas,
        ppLlvmMeta,
        ppLlvmFunctionDecls,
        ppLlvmFunctionDecl,
        ppLlvmFunctions,
        ppLlvmFunction,

        ) where

    #include "HsVersions.h"

    import GhcPrelude

    import Llvm.AbsSyn
    import Llvm.MetaData
    import Llvm.Types

    import Data.List ( intersperse )
    import Outputable
    import Unique
    import FastString ( sLit )

    --------------------------------------------------------------------------------
    -- * Top Level Print functions
    --------------------------------------------------------------------------------

    -- | Print out a whole LLVM module.
    ppLlvmModule :: LlvmModule -> SDoc
    ppLlvmModule (LlvmModule comments aliases meta globals decls funcs)
      = ppLlvmComments comments $+$ newLine
        $+$ ppLlvmAliases aliases $+$ newLine
        $+$ ppLlvmMetas meta $+$ newLine
        $+$ ppLlvmGlobals globals $+$ newLine
        $+$ ppLlvmFunctionDecls decls $+$ newLine
        $+$ ppLlvmFunctions funcs

    -- | Print out a multi-line comment, can be inside a function or on its own
    ppLlvmComments :: [LMString] -> SDoc
    ppLlvmComments comments = vcat $ map ppLlvmComment comments

    -- | Print out a comment, can be inside a function or on its own
    ppLlvmComment :: LMString -> SDoc
    ppLlvmComment com = semi <+> ftext com

    -- | Print out a list of global mutable variable definitions
    ppLlvmGlobals :: [LMGlobal] -> SDoc
    ppLlvmGlobals ls = vcat $ map ppLlvmGlobal ls

    -- | Print out a global mutable variable definition
    ppLlvmGlobal :: LMGlobal -> SDoc
    ppLlvmGlobal (LMGlobal var@(LMGlobalVar _ _ link x a c) dat) =
        let sect = case x of
                Just x' -> text ", section" <+> doubleQuotes (ftext x')
                Nothing -> empty

            align = case a of
                Just a' -> text ", align" <+> int a'
                Nothing -> empty

            rhs = case dat of
                Just stat -> pprSpecialStatic stat
                Nothing   -> ppr (pLower $ getVarType var)

            -- Position of linkage is different for aliases.
            const = case c of
              Global   -> "global"
              Constant -> "constant"
              Alias    -> "alias"

        in ppAssignment var $ ppr link <+> text const <+> rhs <> sect <> align
           $+$ newLine

    ppLlvmGlobal (LMGlobal var val) = sdocWithDynFlags $ \dflags ->
      error $ "Non Global var ppr as global! "
              ++ showSDoc dflags (ppr var) ++ " " ++ showSDoc dflags (ppr val)

    -- | Print out a list of LLVM type aliases.
    ppLlvmAliases :: [LlvmAlias] -> SDoc
    ppLlvmAliases tys = vcat $ map ppLlvmAlias tys

    -- | Print out an LLVM type alias.
    ppLlvmAlias :: LlvmAlias -> SDoc
    ppLlvmAlias (name, ty)
      = char '%' <> ftext name <+> equals <+> text "type" <+> ppr ty

    -- | Print out a list of LLVM metadata.
    ppLlvmMetas :: [MetaDecl] -> SDoc
    ppLlvmMetas metas = vcat $ map ppLlvmMeta metas

    -- | Print out an LLVM metadata definition.
    ppLlvmMeta :: MetaDecl -> SDoc
    ppLlvmMeta (MetaUnnamed n m)
      = ppr n <+> equals <+> ppr m

    ppLlvmMeta (MetaNamed n m)
      = exclamation <> ftext n <+> equals <+> exclamation <> braces nodes
      where
        nodes = hcat $ intersperse comma $ map ppr m

    -- | Print out a list of function definitions.
    ppLlvmFunctions :: LlvmFunctions -> SDoc
    ppLlvmFunctions funcs = vcat $ map ppLlvmFunction funcs

    -- | Print out a function definition.
    ppLlvmFunction :: LlvmFunction -> SDoc
    ppLlvmFunction fun =
        let attrDoc = ppSpaceJoin (funcAttrs fun)
            secDoc = case funcSect fun of
                          Just s' -> text "section" <+> (doubleQuotes $ ftext s')
                          Nothing -> empty
            prefixDoc = case funcPrefix fun of
                            Just v  -> text "prefix" <+> ppr v
                            Nothing -> empty
        in text "define" <+> ppLlvmFunctionHeader (funcDecl fun) (funcArgs fun)
            <+> attrDoc <+> secDoc <+> prefixDoc
            $+$ lbrace
            $+$ ppLlvmBlocks (funcBody fun)
            $+$ rbrace
            $+$ newLine
            $+$ newLine

    -- | Print out a function definition header.
    ppLlvmFunctionHeader :: LlvmFunctionDecl -> [LMString] -> SDoc
    ppLlvmFunctionHeader (LlvmFunctionDecl n l c r varg p a) args
      = let varg' = case varg of
                          VarArgs | null p    -> sLit "..."
                                  | otherwise -> sLit ", ..."
                          _otherwise          -> sLit ""
            align = case a of
                         Just a' -> text " align " <> ppr a'
                         Nothing -> empty
            args' = map (\((ty,p),n) -> ppr ty <+> ppSpaceJoin p <+> char '%'
                                        <> ftext n)
                        (zip p args)
        in ppr l <+> ppr c <+> ppr r <+> char '@' <> ftext n <> lparen <>
            (hsep $ punctuate comma args') <> ptext varg' <> rparen <> align

    -- | Print out a list of function declaration.
    ppLlvmFunctionDecls :: LlvmFunctionDecls -> SDoc
    ppLlvmFunctionDecls decs = vcat $ map ppLlvmFunctionDecl decs

    -- | Print out a function declaration.
    -- Declarations define the function type but don't define the actual body of
    -- the function.
    ppLlvmFunctionDecl :: LlvmFunctionDecl -> SDoc
    ppLlvmFunctionDecl (LlvmFunctionDecl n l c r varg p a)
      = let varg' = case varg of
                          VarArgs | null p    -> sLit "..."
                                  | otherwise -> sLit ", ..."
                          _otherwise          -> sLit ""
            align = case a of
                         Just a' -> text " align" <+> ppr a'
                         Nothing -> empty
            args = hcat $ intersperse (comma <> space) $
                      map (\(t,a) -> ppr t <+> ppSpaceJoin a) p
        in text "declare" <+> ppr l <+> ppr c <+> ppr r <+> char '@' <>
            ftext n <> lparen <> args <> ptext varg' <> rparen <> align $+$ newLine

    -- | Print out a list of LLVM blocks.
    ppLlvmBlocks :: LlvmBlocks -> SDoc
    ppLlvmBlocks blocks = vcat $ map ppLlvmBlock blocks

    -- | Print out an LLVM block.
    -- It must be part of a function definition.
    ppLlvmBlock :: LlvmBlock -> SDoc
    ppLlvmBlock (LlvmBlock blockId stmts) =
      let isLabel (MkLabel _) = True
          isLabel _           = False
          (block, rest)       = break isLabel stmts
          ppRest = case rest of
            MkLabel id:xs -> ppLlvmBlock (LlvmBlock id xs)
            _             -> empty
      in ppLlvmBlockLabel blockId
               $+$ (vcat $ map ppLlvmStatement block)
               $+$ newLine
               $+$ ppRest

    -- | Print out an LLVM block label.
    ppLlvmBlockLabel :: LlvmBlockId -> SDoc
    ppLlvmBlockLabel id = pprUniqueAlways id <> colon

    -- | Print out an LLVM statement.
    ppLlvmStatement :: LlvmStatement -> SDoc
    ppLlvmStatement stmt =
      let ind = (text "  " <>)
      in case stmt of
            Assignment  dst expr      -> ind $ ppAssignment dst (ppLlvmExpression expr)
            Fence       st ord        -> ind $ ppFence st ord
            Branch      target        -> ind $ ppBranch target
            BranchIf    cond ifT ifF  -> ind $ ppBranchIf cond ifT ifF
            Comment     comments      -> ind $ ppLlvmComments comments
            MkLabel     label         -> ppLlvmBlockLabel label
            Store       value ptr     -> ind $ ppStore value ptr
            Switch      scrut def tgs -> ind $ ppSwitch scrut def tgs
            Return      result        -> ind $ ppReturn result
            Expr        expr          -> ind $ ppLlvmExpression expr
            Unreachable               -> ind $ text "unreachable"
            Nop                       -> empty
            MetaStmt    meta s        -> ppMetaStatement meta s

    -- | Print out an LLVM expression.
    ppLlvmExpression :: LlvmExpression -> SDoc
    ppLlvmExpression expr
      = case expr of
            Alloca     tp amount        -> ppAlloca tp amount
            LlvmOp     op left right    -> ppMachOp op left right
            Call       tp fp args attrs -> ppCall tp fp (map MetaVar args) attrs
            CallM      tp fp args attrs -> ppCall tp fp args attrs
            Cast       op from to       -> ppCast op from to
            Compare    op left right    -> ppCmpOp op left right
            Extract    vec idx          -> ppExtract vec idx
            ExtractV   struct idx       -> ppExtractV struct idx
            Insert     vec elt idx      -> ppInsert vec elt idx
            GetElemPtr inb ptr indexes  -> ppGetElementPtr inb ptr indexes
            Load       ptr              -> ppLoad ptr
            ALoad      ord st ptr       -> ppALoad ord st ptr
            Malloc     tp amount        -> ppMalloc tp amount
            AtomicRMW  aop tgt src ordering -> ppAtomicRMW aop tgt src ordering
            CmpXChg    addr old new s_ord f_ord -> ppCmpXChg addr old new s_ord f_ord
            Phi        tp predecessors  -> ppPhi tp predecessors
            Asm        asm c ty v se sk -> ppAsm asm c ty v se sk
            MExpr      meta expr        -> ppMetaExpr meta expr

    --------------------------------------------------------------------------------
    -- * Individual print functions
    --------------------------------------------------------------------------------

    -- | Should always be a function pointer. So a global var of function type
    -- (since globals are always pointers) or a local var of pointer function type.
    ppCall :: LlvmCallType -> LlvmVar -> [MetaExpr] -> [LlvmFuncAttr] -> SDoc
    ppCall ct fptr args attrs = case fptr of
                               --
        -- if local var function pointer, unwrap
        LMLocalVar _ (LMPointer (LMFunction d)) -> ppCall' d

        -- should be function type otherwise
        LMGlobalVar _ (LMFunction d) _ _ _ _    -> ppCall' d

        -- not pointer or function, so error
        _other -> error $ "ppCall called with non LMFunction type!\nMust be "
                    ++ " called with either global var of function type or "
                    ++ "local var of pointer function type."

        where
            ppCall' (LlvmFunctionDecl _ _ cc ret argTy params _) =
                let tc = if ct == TailCall then text "tail " else empty
                    ppValues = hsep $ punctuate comma $ map ppCallMetaExpr args
                    ppArgTy  = (ppCommaJoin $ map fst params) <>
                               (case argTy of
                                   VarArgs   -> text ", ..."
                                   FixedArgs -> empty)
                    fnty = space <> lparen <> ppArgTy <> rparen
                    attrDoc = ppSpaceJoin attrs
                in  tc <> text "call" <+> ppr cc <+> ppr ret
                        <> fnty <+> ppName fptr <> lparen <+> ppValues
                        <+> rparen <+> attrDoc

            -- Metadata needs to be marked as having the `metadata` type when used
            -- in a call argument
            ppCallMetaExpr (MetaVar v) = ppr v
            ppCallMetaExpr v           = text "metadata" <+> ppr v

    ppMachOp :: LlvmMachOp -> LlvmVar -> LlvmVar -> SDoc
    ppMachOp op left right =
      (ppr op) <+> (ppr (getVarType left)) <+> ppName left
            <> comma <+> ppName right

    ppCmpOp :: LlvmCmpOp -> LlvmVar -> LlvmVar -> SDoc
    ppCmpOp op left right =
      let cmpOp
            | isInt (getVarType left) && isInt (getVarType right) = text "icmp"
            | isFloat (getVarType left) && isFloat (getVarType right) = text "fcmp"
            | otherwise = text "icmp" -- Just continue as its much easier to debug
            {-
            | otherwise = error ("can't compare different types, left = "
                    ++ (show $ getVarType left) ++ ", right = "
                    ++ (show $ getVarType right))
            -}
      in cmpOp <+> ppr op <+> ppr (getVarType left)
            <+> ppName left <> comma <+> ppName right

    ppAssignment :: LlvmVar -> SDoc -> SDoc
    ppAssignment var expr = ppName var <+> equals <+> expr

    ppFence :: Bool -> LlvmSyncOrdering -> SDoc
    ppFence st ord =
      let singleThread = case st of True  -> text "singlethread"
                                    False -> empty
      in text "fence" <+> singleThread <+> ppSyncOrdering ord

    ppSyncOrdering :: LlvmSyncOrdering -> SDoc
    ppSyncOrdering SyncUnord     = text "unordered"
    ppSyncOrdering SyncMonotonic = text "monotonic"
    ppSyncOrdering SyncAcquire   = text "acquire"
    ppSyncOrdering SyncRelease   = text "release"
    ppSyncOrdering SyncAcqRel    = text "acq_rel"
    ppSyncOrdering SyncSeqCst    = text "seq_cst"

    ppAtomicOp :: LlvmAtomicOp -> SDoc
    ppAtomicOp LAO_Xchg = text "xchg"
    ppAtomicOp LAO_Add  = text "add"
    ppAtomicOp LAO_Sub  = text "sub"
    ppAtomicOp LAO_And  = text "and"
    ppAtomicOp LAO_Nand = text "nand"
    ppAtomicOp LAO_Or   = text "or"
    ppAtomicOp LAO_Xor  = text "xor"
    ppAtomicOp LAO_Max  = text "max"
    ppAtomicOp LAO_Min  = text "min"
    ppAtomicOp LAO_Umax = text "umax"
    ppAtomicOp LAO_Umin = text "umin"

    ppAtomicRMW :: LlvmAtomicOp -> LlvmVar -> LlvmVar -> LlvmSyncOrdering -> SDoc
    ppAtomicRMW aop tgt src ordering =
      text "atomicrmw" <+> ppAtomicOp aop <+> ppr tgt <> comma
      <+> ppr src <+> ppSyncOrdering ordering

    ppCmpXChg :: LlvmVar -> LlvmVar -> LlvmVar
              -> LlvmSyncOrdering -> LlvmSyncOrdering -> SDoc
    ppCmpXChg addr old new s_ord f_ord =
      text "cmpxchg" <+> ppr addr <> comma <+> ppr old <> comma <+> ppr new
      <+> ppSyncOrdering s_ord <+> ppSyncOrdering f_ord

    -- XXX: On x86, vector types need to be 16-byte aligned for aligned access, but
    -- we have no way of guaranteeing that this is true with GHC (we would need to
    -- modify the layout of the stack and closures, change the storage manager,
    -- etc.). So, we blindly tell LLVM that *any* vector store or load could be
    -- unaligned. In the future we may be able to guarantee that certain vector
    -- access patterns are aligned, in which case we will need a more granular way
    -- of specifying alignment.

    ppLoad :: LlvmVar -> SDoc
    ppLoad var = text "load" <+> ppr derefType <> comma <+> ppr var <> align
      where
        derefType = pLower $ getVarType var
        align | isVector . pLower . getVarType $ var = text ", align 1"
              | otherwise = empty

    ppALoad :: LlvmSyncOrdering -> SingleThreaded -> LlvmVar -> SDoc
    ppALoad ord st var = sdocWithDynFlags $ \dflags ->
      let alignment = (llvmWidthInBits dflags $ getVarType var) `quot` 8
          align     = text ", align" <+> ppr alignment
          sThreaded | st        = text " singlethread"
                    | otherwise = empty
          derefType = pLower $ getVarType var
      in text "load atomic" <+> ppr derefType <> comma <+> ppr var <> sThreaded
                <+> ppSyncOrdering ord <> align

    ppStore :: LlvmVar -> LlvmVar -> SDoc
    ppStore val dst
        | isVecPtrVar dst = text "store" <+> ppr val <> comma <+> ppr dst <>
                            comma <+> text "align 1"
        | otherwise       = text "store" <+> ppr val <> comma <+> ppr dst
      where
        isVecPtrVar :: LlvmVar -> Bool
        isVecPtrVar = isVector . pLower . getVarType

    ppCast :: LlvmCastOp -> LlvmVar -> LlvmType -> SDoc
    ppCast op from to
        =   ppr op
        <+> ppr (getVarType from) <+> ppName from
        <+> text "to"
        <+> ppr to

    ppMalloc :: LlvmType -> Int -> SDoc
    ppMalloc tp amount =
      let amount' = LMLitVar $ LMIntLit (toInteger amount) i32
      in text "malloc" <+> ppr tp <> comma <+> ppr amount'

    ppAlloca :: LlvmType -> Int -> SDoc
    ppAlloca tp amount =
      let amount' = LMLitVar $ LMIntLit (toInteger amount) i32
      in text "alloca" <+> ppr tp <> comma <+> ppr amount'

    ppGetElementPtr :: Bool -> LlvmVar -> [LlvmVar] -> SDoc
    ppGetElementPtr inb ptr idx =
      let indexes = comma <+> ppCommaJoin idx
          inbound = if inb then text "inbounds" else empty
          derefType = pLower $ getVarType ptr
      in text "getelementptr" <+> inbound <+> ppr derefType <> comma <+> ppr ptr
                                <> indexes

    ppReturn :: Maybe LlvmVar -> SDoc
    ppReturn (Just var) = text "ret" <+> ppr var
    ppReturn Nothing    = text "ret" <+> ppr LMVoid

    ppBranch :: LlvmVar -> SDoc
    ppBranch var = text "br" <+> ppr var

    ppBranchIf :: LlvmVar -> LlvmVar -> LlvmVar -> SDoc
    ppBranchIf cond trueT falseT
      = text "br" <+> ppr cond <> comma <+> ppr trueT <> comma <+> ppr falseT

    ppPhi :: LlvmType -> [(LlvmVar,LlvmVar)] -> SDoc
    ppPhi tp preds =
      let ppPreds (val, label) = brackets $ ppName val <> comma <+> ppName label
      in text "phi" <+> ppr tp <+> hsep (punctuate comma $ map ppPreds preds)

    ppSwitch :: LlvmVar -> LlvmVar -> [(LlvmVar,LlvmVar)] -> SDoc
    ppSwitch scrut dflt targets =
      let ppTarget  (val, lab) = ppr val <> comma <+> ppr lab
          ppTargets  xs        = brackets $ vcat (map ppTarget xs)
      in text "switch" <+> ppr scrut <> comma <+> ppr dflt
            <+> ppTargets targets

    ppAsm :: LMString -> LMString -> LlvmType -> [LlvmVar] -> Bool -> Bool -> SDoc
    ppAsm asm constraints rty vars sideeffect alignstack =
      let asm'  = doubleQuotes $ ftext asm
          cons  = doubleQuotes $ ftext constraints
          rty'  = ppr rty
          vars' = lparen <+> ppCommaJoin vars <+> rparen
          side  = if sideeffect then text "sideeffect" else empty
          align = if alignstack then text "alignstack" else empty
      in text "call" <+> rty' <+> text "asm" <+> side <+> align <+> asm' <> comma
            <+> cons <> vars'

    ppExtract :: LlvmVar -> LlvmVar -> SDoc
    ppExtract vec idx =
        text "extractelement"
        <+> ppr (getVarType vec) <+> ppName vec <> comma
        <+> ppr idx

    ppExtractV :: LlvmVar -> Int -> SDoc
    ppExtractV struct idx =
        text "extractvalue"
        <+> ppr (getVarType struct) <+> ppName struct <> comma
        <+> ppr idx

    ppInsert :: LlvmVar -> LlvmVar -> LlvmVar -> SDoc
    ppInsert vec elt idx =
        text "insertelement"
        <+> ppr (getVarType vec) <+> ppName vec <> comma
        <+> ppr (getVarType elt) <+> ppName elt <> comma
        <+> ppr idx

    ppMetaStatement :: [MetaAnnot] -> LlvmStatement -> SDoc
    ppMetaStatement meta stmt = ppLlvmStatement stmt <> ppMetaAnnots meta

    ppMetaExpr :: [MetaAnnot] -> LlvmExpression -> SDoc
    ppMetaExpr meta expr = ppLlvmExpression expr <> ppMetaAnnots meta

    ppMetaAnnots :: [MetaAnnot] -> SDoc
    ppMetaAnnots meta = hcat $ map ppMeta meta
      where
        ppMeta (MetaAnnot name e)
            = comma <+> exclamation <> ftext name <+>
              case e of
                MetaNode n    -> ppr n
                MetaStruct ms -> exclamation <> braces (ppCommaJoin ms)
                other         -> exclamation <> braces (ppr other) -- possible?

    --------------------------------------------------------------------------------
    -- * Misc functions
    --------------------------------------------------------------------------------

    -- | Blank line.
    newLine :: SDoc
    newLine = empty

    -- | Exclamation point.
    exclamation :: SDoc
    exclamation = char '!'