LlvmCodeGen.hs 5.72 KB
Newer Older
1 2
{-# LANGUAGE CPP, TypeFamilies #-}

3 4 5
-- -----------------------------------------------------------------------------
-- | This is the top-level module in the LLVM code generator.
--
6
module LlvmCodeGen ( llvmCodeGen, llvmFixupAsm ) where
7 8 9

#include "HsVersions.h"

dterei's avatar
dterei committed
10
import Llvm
11 12 13 14
import LlvmCodeGen.Base
import LlvmCodeGen.CodeGen
import LlvmCodeGen.Data
import LlvmCodeGen.Ppr
Peter Wortmann's avatar
Peter Wortmann committed
15
import LlvmCodeGen.Regs
16 17
import LlvmMangler

18
import CgUtils ( fixStgRegisters )
19 20 21
import Cmm
import Hoopl
import PprCmm
22 23 24 25

import BufWrite
import DynFlags
import ErrUtils
dterei's avatar
dterei committed
26
import FastString
27 28
import Outputable
import UniqSupply
29
import SysTools ( figureLlvmVersion )
Peter Wortmann's avatar
Peter Wortmann committed
30
import qualified Stream
31

32
import Control.Monad ( when )
Peter Wortmann's avatar
Peter Wortmann committed
33
import Data.Maybe ( fromMaybe, catMaybes )
34 35 36
import System.IO

-- -----------------------------------------------------------------------------
dterei's avatar
dterei committed
37
-- | Top-level of the LLVM Code generator
38
--
Peter Wortmann's avatar
Peter Wortmann committed
39 40 41 42 43 44 45 46
llvmCodeGen :: DynFlags -> Handle -> UniqSupply
               -> Stream.Stream IO RawCmmGroup ()
               -> IO ()
llvmCodeGen dflags h us cmm_stream
  = do bufh <- newBufHandle h

       -- Pass header
       showPass dflags "LLVM CodeGen"
47

Peter Wortmann's avatar
Peter Wortmann committed
48
       -- get llvm version, cache for later use
49
       ver <- (fromMaybe supportedLlvmVersion) `fmap` figureLlvmVersion dflags
Peter Wortmann's avatar
Peter Wortmann committed
50 51 52 53 54

       -- warn if unsupported
       debugTraceMsg dflags 2
            (text "Using LLVM version:" <+> text (show ver))
       let doWarn = wopt Opt_WarnUnsupportedLlvmVersion dflags
55 56
       when (ver /= supportedLlvmVersion && doWarn) $
           putMsg dflags (text "You are using an unsupported version of LLVM!"
Peter Wortmann's avatar
Peter Wortmann committed
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
                            $+$ text "We will try though...")

       -- run code generation
       runLlvm dflags ver bufh us $
         llvmCodeGen' (liftStream cmm_stream)

       bFlush bufh

llvmCodeGen' :: Stream.Stream LlvmM RawCmmGroup () -> LlvmM ()
llvmCodeGen' cmm_stream
  = do  -- Preamble
        renderLlvm pprLlvmHeader
        ghcInternalFunctions
        cmmMetaLlvmPrelude

        -- Procedures
        let llvmStream = Stream.mapM llvmGroupLlvmGens cmm_stream
        _ <- Stream.collect llvmStream

        -- Declare aliases for forward references
77
        renderLlvm . pprLlvmData =<< generateExternDecls
Peter Wortmann's avatar
Peter Wortmann committed
78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

        -- Postamble
        cmmUsedLlvmGens

llvmGroupLlvmGens :: RawCmmGroup -> LlvmM ()
llvmGroupLlvmGens cmm = do

        -- Insert functions into map, collect data
        let split (CmmData s d' )     = return $ Just (s, d')
            split (CmmProc h l live g) = do
              -- Set function type
              let l' = case mapLookup (g_entry g) h of
                         Nothing                   -> l
                         Just (Statics info_lbl _) -> info_lbl
              lml <- strCLabel_llvm l'
              funInsert lml =<< llvmFunTy live
              return Nothing
        cdata <- fmap catMaybes $ mapM split cmm

        {-# SCC "llvm_datas_gen" #-}
          cmmDataLlvmGens cdata
        {-# SCC "llvm_procs_gen" #-}
          mapM_ cmmLlvmGen cmm
101 102

-- -----------------------------------------------------------------------------
dterei's avatar
dterei committed
103
-- | Do LLVM code generation on all these Cmms data sections.
104
--
Peter Wortmann's avatar
Peter Wortmann committed
105
cmmDataLlvmGens :: [(Section,CmmStatics)] -> LlvmM ()
106

Peter Wortmann's avatar
Peter Wortmann committed
107 108
cmmDataLlvmGens statics
  = do lmdatas <- mapM genLlvmData statics
109

Peter Wortmann's avatar
Peter Wortmann committed
110
       let (gss, tss) = unzip lmdatas
111

Peter Wortmann's avatar
Peter Wortmann committed
112 113 114 115
       let regGlobal (LMGlobal (LMGlobalVar l ty _ _ _ _) _)
                        = funInsert l ty
           regGlobal _  = return ()
       mapM_ regGlobal (concat gss)
116
       gss' <- mapM aliasify $ concat gss
Peter Wortmann's avatar
Peter Wortmann committed
117

118
       renderLlvm $ pprLlvmData (concat gss', concat tss)
119

dterei's avatar
dterei committed
120
-- | Complete LLVM code generation phase for a single top-level chunk of Cmm.
Peter Wortmann's avatar
Peter Wortmann committed
121 122 123
cmmLlvmGen ::RawCmmDecl -> LlvmM ()
cmmLlvmGen cmm@CmmProc{} = do

124
    -- rewrite assignments to global regs
Peter Wortmann's avatar
Peter Wortmann committed
125
    dflags <- getDynFlag id
dterei's avatar
dterei committed
126
    let fixed_cmm = {-# SCC "llvm_fix_regs" #-}
127
                    fixStgRegisters dflags cmm
128

Peter Wortmann's avatar
Peter Wortmann committed
129
    dumpIfSetLlvm Opt_D_dump_opt_cmm "Optimised Cmm" (pprCmmGroup [fixed_cmm])
130 131

    -- generate llvm code from cmm
Peter Wortmann's avatar
Peter Wortmann committed
132
    llvmBC <- withClearVars $ genLlvmProc fixed_cmm
133

Peter Wortmann's avatar
Peter Wortmann committed
134
    -- pretty print
135
    (docs, ivars) <- fmap unzip $ mapM pprLlvmCmmDecl llvmBC
Peter Wortmann's avatar
Peter Wortmann committed
136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165

    -- Output, note down used variables
    renderLlvm (vcat docs)
    mapM_ markUsedVar $ concat ivars

cmmLlvmGen _ = return ()

-- -----------------------------------------------------------------------------
-- | Generate meta data nodes
--

cmmMetaLlvmPrelude :: LlvmM ()
cmmMetaLlvmPrelude = do
  metas <- flip mapM stgTBAA $ \(uniq, name, parent) -> do
    -- Generate / lookup meta data IDs
    tbaaId <- getMetaUniqueId
    setUniqMeta uniq tbaaId
    parentId <- maybe (return Nothing) getUniqMeta parent
    -- Build definition
    return $ MetaUnamed tbaaId $ MetaStruct
        [ MetaStr name
        , case parentId of
          Just p  -> MetaNode p
          Nothing -> MetaVar $ LMLitVar $ LMNullLit i8Ptr
        ]
  renderLlvm $ ppLlvmMetas metas

-- -----------------------------------------------------------------------------
-- | Marks variables as used where necessary
--
166

Peter Wortmann's avatar
Peter Wortmann committed
167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186
cmmUsedLlvmGens :: LlvmM ()
cmmUsedLlvmGens = do

  -- LLVM would discard variables that are internal and not obviously
  -- used if we didn't provide these hints. This will generate a
  -- definition of the form
  --
  --   @llvm.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
  --
  -- Which is the LLVM way of protecting them against getting removed.
  ivars <- getUsedVars
  let cast x = LMBitc (LMStaticPointer (pVarLift x)) i8Ptr
      ty     = (LMArray (length ivars) i8Ptr)
      usedArray = LMStaticArray (map cast ivars) ty
      sectName  = Just $ fsLit "llvm.metadata"
      lmUsedVar = LMGlobalVar (fsLit "llvm.used") ty Appending sectName Nothing Constant
      lmUsed    = LMGlobal lmUsedVar (Just usedArray)
  if null ivars
     then return ()
     else renderLlvm $ pprLlvmData ([lmUsed], [])