summaryrefslogtreecommitdiff
path: root/compiler/llvmGen/LlvmCodeGen/Data.hs
blob: 3651a88cc6529043d9540fb4e491c7619b72f503 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
{-# LANGUAGE CPP #-}
-- ----------------------------------------------------------------------------
-- | Handle conversion of CmmData to LLVM code.
--

module LlvmCodeGen.Data (
        genLlvmData, genData
    ) where

#include "HsVersions.h"

import GhcPrelude

import Llvm
import LlvmCodeGen.Base

import BlockId
import CLabel
import Cmm
import DynFlags
import Platform

import FastString
import Outputable
import qualified Data.ByteString as BS

-- ----------------------------------------------------------------------------
-- * Constants
--

-- | The string appended to a variable name to create its structure type alias
structStr :: LMString
structStr = fsLit "_struct"

-- | The LLVM visibility of the label
linkage :: CLabel -> LlvmLinkageType
linkage lbl = if externallyVisibleCLabel lbl
              then ExternallyVisible else Internal

-- ----------------------------------------------------------------------------
-- * Top level
--

-- | Pass a CmmStatic section to an equivalent Llvm code.
genLlvmData :: (Section, CmmStatics) -> LlvmM LlvmData
-- See note [emit-time elimination of static indirections] in CLabel.
genLlvmData (_, Statics alias [CmmStaticLit (CmmLabel lbl), CmmStaticLit ind, _, _])
  | lbl == mkIndStaticInfoLabel
  , let labelInd (CmmLabelOff l _) = Just l
        labelInd (CmmLabel l) = Just l
        labelInd _ = Nothing
  , Just ind' <- labelInd ind
  , alias `mayRedirectTo` ind' = do
    label <- strCLabel_llvm alias
    label' <- strCLabel_llvm ind'
    let link     = linkage alias
        link'    = linkage ind'
        -- the LLVM type we give the alias is an empty struct type
        -- but it doesn't really matter, as the pointer is only
        -- used for (bit/int)casting.
        tyAlias  = LMAlias (label `appendFS` structStr, LMStructU [])

        aliasDef = LMGlobalVar label tyAlias link Nothing Nothing Alias
        -- we don't know the type of the indirectee here
        indType  = panic "will be filled by 'aliasify', later"
        orig     = LMStaticPointer $ LMGlobalVar label' indType link' Nothing Nothing Alias

    pure ([LMGlobal aliasDef $ Just orig], [tyAlias])

genLlvmData (sec, Statics lbl xs) = do
    label <- strCLabel_llvm lbl
    static <- mapM genData xs
    lmsec <- llvmSection sec
    let types   = map getStatType static

        strucTy = LMStruct types
        tyAlias = LMAlias (label `appendFS` structStr, strucTy)

        struct         = Just $ LMStaticStruc static tyAlias
        link           = linkage lbl
        align          = case sec of
                            Section CString _ -> Just 1
                            _                 -> Nothing
        const          = if isSecConstant sec then Constant else Global
        varDef         = LMGlobalVar label tyAlias link lmsec align const
        globDef        = LMGlobal varDef struct

    return ([globDef], [tyAlias])

-- | Format the section type part of a Cmm Section
llvmSectionType :: Platform -> SectionType -> FastString
llvmSectionType p t = case t of
    Text                    -> fsLit ".text"
    ReadOnlyData            -> case platformOS p of
                                 OSMinGW32 -> fsLit ".rdata"
                                 _         -> fsLit ".rodata"
    RelocatableReadOnlyData -> case platformOS p of
                                 OSMinGW32 -> fsLit ".rdata$rel.ro"
                                 _         -> fsLit ".data.rel.ro"
    ReadOnlyData16          -> case platformOS p of
                                 OSMinGW32 -> fsLit ".rdata$cst16"
                                 _         -> fsLit ".rodata.cst16"
    Data                    -> fsLit ".data"
    UninitialisedData       -> fsLit ".bss"
    CString                 -> case platformOS p of
                                 OSMinGW32 -> fsLit ".rdata$str"
                                 _         -> fsLit ".rodata.str"
    (OtherSection _)        -> panic "llvmSectionType: unknown section type"

-- | Format a Cmm Section into a LLVM section name
llvmSection :: Section -> LlvmM LMSection
llvmSection (Section t suffix) = do
  dflags <- getDynFlags
  let splitSect = gopt Opt_SplitSections dflags
      platform  = targetPlatform dflags
  if not splitSect
  then return Nothing
  else do
    lmsuffix <- strCLabel_llvm suffix
    let result sep = Just (concatFS [llvmSectionType platform t
                                    , fsLit sep, lmsuffix])
    case platformOS platform of
      OSMinGW32 -> return (result "$")
      _         -> return (result ".")

-- ----------------------------------------------------------------------------
-- * Generate static data
--

-- | Handle static data
genData :: CmmStatic -> LlvmM LlvmStatic

genData (CmmString str) = do
    let v  = map (\x -> LMStaticLit $ LMIntLit (fromIntegral x) i8)
                 (BS.unpack str)
        ve = v ++ [LMStaticLit $ LMIntLit 0 i8]
    return $ LMStaticArray ve (LMArray (length ve) i8)

genData (CmmUninitialised bytes)
    = return $ LMUninitType (LMArray bytes i8)

genData (CmmStaticLit lit)
    = genStaticLit lit

-- | Generate Llvm code for a static literal.
--
-- Will either generate the code or leave it unresolved if it is a 'CLabel'
-- which isn't yet known.
genStaticLit :: CmmLit -> LlvmM LlvmStatic
genStaticLit (CmmInt i w)
    = return $ LMStaticLit (LMIntLit i (LMInt $ widthInBits w))

genStaticLit (CmmFloat r w)
    = return $ LMStaticLit (LMFloatLit (fromRational r) (widthToLlvmFloat w))

genStaticLit (CmmVec ls)
    = do sls <- mapM toLlvmLit ls
         return $ LMStaticLit (LMVectorLit sls)
  where
    toLlvmLit :: CmmLit -> LlvmM LlvmLit
    toLlvmLit lit = do
      slit <- genStaticLit lit
      case slit of
        LMStaticLit llvmLit -> return llvmLit
        _ -> panic "genStaticLit"

-- Leave unresolved, will fix later
genStaticLit cmm@(CmmLabel l) = do
    var <- getGlobalPtr =<< strCLabel_llvm l
    dflags <- getDynFlags
    let ptr = LMStaticPointer var
        lmty = cmmToLlvmType $ cmmLitType dflags cmm
    return $ LMPtoI ptr lmty

genStaticLit (CmmLabelOff label off) = do
    dflags <- getDynFlags
    var <- genStaticLit (CmmLabel label)
    let offset = LMStaticLit $ LMIntLit (toInteger off) (llvmWord dflags)
    return $ LMAdd var offset

genStaticLit (CmmLabelDiffOff l1 l2 off w) = do
    dflags <- getDynFlags
    var1 <- genStaticLit (CmmLabel l1)
    var2 <- genStaticLit (CmmLabel l2)
    let var
          | w == wordWidth dflags = LMSub var1 var2
          | otherwise = LMTrunc (LMSub var1 var2) (widthToLlvmInt w)
        offset = LMStaticLit $ LMIntLit (toInteger off) (LMInt $ widthInBits w)
    return $ LMAdd var offset

genStaticLit (CmmBlock b) = genStaticLit $ CmmLabel $ infoTblLbl b

genStaticLit (CmmHighStackMark)
    = panic "genStaticLit: CmmHighStackMark unsupported!"