ghc-8.2.1: cmm/PprC.hs
{-# LANGUAGE CPP, GADTs #-}
-----------------------------------------------------------------------------
--
-- Pretty-printing of Cmm as C, suitable for feeding gcc
--
-- (c) The University of Glasgow 2004-2006
--
-- Print Cmm as real C, for -fvia-C
--
-- See wiki:Commentary/Compiler/Backends/PprC
--
-- This is simpler than the old PprAbsC, because Cmm is "macro-expanded"
-- relative to the old AbstractC, and many oddities/decorations have
-- disappeared from the data type.
--
-- This code generator is only supported in unregisterised mode.
--
-----------------------------------------------------------------------------
module PprC (
writeCs,
pprStringInCStyle
) where
#include "HsVersions.h"
-- Cmm stuff
import BlockId
import CLabel
import ForeignCall
import Cmm hiding (pprBBlock)
import PprCmm ()
import Hoopl
import CmmUtils
import CmmSwitch
-- Utils
import CPrim
import DynFlags
import FastString
import Outputable
import Platform
import UniqSet
import UniqFM
import Unique
import Util
-- The rest
import Control.Monad.ST
import Data.Bits
import Data.Char
import Data.List
import Data.Map (Map)
import Data.Word
import System.IO
import qualified Data.Map as Map
import Control.Monad (liftM, ap)
import qualified Data.Array.Unsafe as U ( castSTUArray )
import Data.Array.ST
-- --------------------------------------------------------------------------
-- Top level
pprCs :: DynFlags -> [RawCmmGroup] -> SDoc
pprCs dflags cmms
= pprCode CStyle (vcat $ map (\c -> split_marker $$ pprC c) cmms)
where
split_marker
| gopt Opt_SplitObjs dflags = text "__STG_SPLIT_MARKER"
| otherwise = empty
writeCs :: DynFlags -> Handle -> [RawCmmGroup] -> IO ()
writeCs dflags handle cmms
= printForC dflags handle (pprCs dflags cmms)
-- --------------------------------------------------------------------------
-- Now do some real work
--
-- for fun, we could call cmmToCmm over the tops...
--
pprC :: RawCmmGroup -> SDoc
pprC tops = vcat $ intersperse blankLine $ map pprTop tops
--
-- top level procs
--
pprTop :: RawCmmDecl -> SDoc
pprTop (CmmProc infos clbl _ graph) =
(case mapLookup (g_entry graph) infos of
Nothing -> empty
Just (Statics info_clbl info_dat) -> pprDataExterns info_dat $$
pprWordArray info_clbl info_dat) $$
(vcat [
blankLine,
extern_decls,
(if (externallyVisibleCLabel clbl)
then mkFN_ else mkIF_) (ppr clbl) <+> lbrace,
nest 8 temp_decls,
vcat (map pprBBlock blocks),
rbrace ]
)
where
blocks = toBlockListEntryFirst graph
(temp_decls, extern_decls) = pprTempAndExternDecls blocks
-- Chunks of static data.
-- We only handle (a) arrays of word-sized things and (b) strings.
pprTop (CmmData _section (Statics lbl [CmmString str])) =
hcat [
pprLocalness lbl, text "char ", ppr lbl,
text "[] = ", pprStringInCStyle str, semi
]
pprTop (CmmData _section (Statics lbl [CmmUninitialised size])) =
hcat [
pprLocalness lbl, text "char ", ppr lbl,
brackets (int size), semi
]
pprTop (CmmData _section (Statics lbl lits)) =
pprDataExterns lits $$
pprWordArray lbl lits
-- --------------------------------------------------------------------------
-- BasicBlocks are self-contained entities: they always end in a jump.
--
-- Like nativeGen/AsmCodeGen, we could probably reorder blocks to turn
-- as many jumps as possible into fall throughs.
--
pprBBlock :: CmmBlock -> SDoc
pprBBlock block =
nest 4 (pprBlockId (entryLabel block) <> colon) $$
nest 8 (vcat (map pprStmt (blockToList nodes)) $$ pprStmt last)
where
(_, nodes, last) = blockSplit block
-- --------------------------------------------------------------------------
-- Info tables. Just arrays of words.
-- See codeGen/ClosureInfo, and nativeGen/PprMach
pprWordArray :: CLabel -> [CmmStatic] -> SDoc
pprWordArray lbl ds
= sdocWithDynFlags $ \dflags ->
hcat [ pprLocalness lbl, text "StgWord"
, space, ppr lbl, text "[]"
-- See Note [StgWord alignment]
, pprAlignment (wordWidth dflags)
, text "= {" ]
$$ nest 8 (commafy (pprStatics dflags ds))
$$ text "};"
pprAlignment :: Width -> SDoc
pprAlignment words =
text "__attribute__((aligned(" <> int (widthInBytes words) <> text ")))"
-- Note [StgWord alignment]
-- C codegen builds static closures as StgWord C arrays (pprWordArray).
-- Their real C type is 'StgClosure'. Macros like UNTAG_CLOSURE assume
-- pointers to 'StgClosure' are aligned at pointer size boundary:
-- 4 byte boundary on 32 systems
-- and 8 bytes on 64-bit systems
-- see TAG_MASK and TAG_BITS definition and usage.
--
-- It's a reasonable assumption also known as natural alignment.
-- Although some architectures have different alignment rules.
-- One of known exceptions is m68k (Trac #11395, comment:16) where:
-- __alignof__(StgWord) == 2, sizeof(StgWord) == 4
--
-- Thus we explicitly increase alignment by using
-- __attribute__((aligned(4)))
-- declaration.
--
-- has to be static, if it isn't globally visible
--
pprLocalness :: CLabel -> SDoc
pprLocalness lbl | not $ externallyVisibleCLabel lbl = text "static "
| otherwise = empty
-- --------------------------------------------------------------------------
-- Statements.
--
pprStmt :: CmmNode e x -> SDoc
pprStmt stmt =
sdocWithDynFlags $ \dflags ->
case stmt of
CmmEntry{} -> empty
CmmComment _ -> empty -- (hang (text "/*") 3 (ftext s)) $$ ptext (sLit "*/")
-- XXX if the string contains "*/", we need to fix it
-- XXX we probably want to emit these comments when
-- some debugging option is on. They can get quite
-- large.
CmmTick _ -> empty
CmmUnwind{} -> empty
CmmAssign dest src -> pprAssign dflags dest src
CmmStore dest src
| typeWidth rep == W64 && wordWidth dflags /= W64
-> (if isFloatType rep then text "ASSIGN_DBL"
else ptext (sLit ("ASSIGN_Word64"))) <>
parens (mkP_ <> pprExpr1 dest <> comma <> pprExpr src) <> semi
| otherwise
-> hsep [ pprExpr (CmmLoad dest rep), equals, pprExpr src <> semi ]
where
rep = cmmExprType dflags src
CmmUnsafeForeignCall target@(ForeignTarget fn conv) results args ->
fnCall
where
(res_hints, arg_hints) = foreignTargetHints target
hresults = zip results res_hints
hargs = zip args arg_hints
ForeignConvention cconv _ _ ret = conv
cast_fn = parens (cCast (pprCFunType (char '*') cconv hresults hargs) fn)
-- See wiki:Commentary/Compiler/Backends/PprC#Prototypes
fnCall =
case fn of
CmmLit (CmmLabel lbl)
| StdCallConv <- cconv ->
pprCall (ppr lbl) cconv hresults hargs
-- stdcall functions must be declared with
-- a function type, otherwise the C compiler
-- doesn't add the @n suffix to the label. We
-- can't add the @n suffix ourselves, because
-- it isn't valid C.
| CmmNeverReturns <- ret ->
pprCall cast_fn cconv hresults hargs <> semi
| not (isMathFun lbl) ->
pprForeignCall (ppr lbl) cconv hresults hargs
_ ->
pprCall cast_fn cconv hresults hargs <> semi
-- for a dynamic call, no declaration is necessary.
CmmUnsafeForeignCall (PrimTarget MO_Touch) _results _args -> empty
CmmUnsafeForeignCall (PrimTarget (MO_Prefetch_Data _)) _results _args -> empty
CmmUnsafeForeignCall target@(PrimTarget op) results args ->
fn_call
where
cconv = CCallConv
fn = pprCallishMachOp_for_C op
(res_hints, arg_hints) = foreignTargetHints target
hresults = zip results res_hints
hargs = zip args arg_hints
fn_call
-- The mem primops carry an extra alignment arg.
-- We could maybe emit an alignment directive using this info.
-- We also need to cast mem primops to prevent conflicts with GCC
-- builtins (see bug #5967).
| Just _align <- machOpMemcpyishAlign op
= (text ";EFF_(" <> fn <> char ')' <> semi) $$
pprForeignCall fn cconv hresults hargs
| otherwise
= pprCall fn cconv hresults hargs
CmmBranch ident -> pprBranch ident
CmmCondBranch expr yes no _ -> pprCondBranch expr yes no
CmmCall { cml_target = expr } -> mkJMP_ (pprExpr expr) <> semi
CmmSwitch arg ids -> sdocWithDynFlags $ \dflags ->
pprSwitch dflags arg ids
_other -> pprPanic "PprC.pprStmt" (ppr stmt)
type Hinted a = (a, ForeignHint)
pprForeignCall :: SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual]
-> SDoc
pprForeignCall fn cconv results args = fn_call
where
fn_call = braces (
pprCFunType (char '*' <> text "ghcFunPtr") cconv results args <> semi
$$ text "ghcFunPtr" <+> equals <+> cast_fn <> semi
$$ pprCall (text "ghcFunPtr") cconv results args <> semi
)
cast_fn = parens (parens (pprCFunType (char '*') cconv results args) <> fn)
pprCFunType :: SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual] -> SDoc
pprCFunType ppr_fn cconv ress args
= sdocWithDynFlags $ \dflags ->
let res_type [] = text "void"
res_type [(one, hint)] = machRepHintCType (localRegType one) hint
res_type _ = panic "pprCFunType: only void or 1 return value supported"
arg_type (expr, hint) = machRepHintCType (cmmExprType dflags expr) hint
in res_type ress <+>
parens (ccallConvAttribute cconv <> ppr_fn) <>
parens (commafy (map arg_type args))
-- ---------------------------------------------------------------------
-- unconditional branches
pprBranch :: BlockId -> SDoc
pprBranch ident = text "goto" <+> pprBlockId ident <> semi
-- ---------------------------------------------------------------------
-- conditional branches to local labels
pprCondBranch :: CmmExpr -> BlockId -> BlockId -> SDoc
pprCondBranch expr yes no
= hsep [ text "if" , parens(pprExpr expr) ,
text "goto", pprBlockId yes <> semi,
text "else goto", pprBlockId no <> semi ]
-- ---------------------------------------------------------------------
-- a local table branch
--
-- we find the fall-through cases
--
pprSwitch :: DynFlags -> CmmExpr -> SwitchTargets -> SDoc
pprSwitch dflags e ids
= (hang (text "switch" <+> parens ( pprExpr e ) <+> lbrace)
4 (vcat ( map caseify pairs ) $$ def)) $$ rbrace
where
(pairs, mbdef) = switchTargetsFallThrough ids
-- fall through case
caseify (ix:ixs, ident) = vcat (map do_fallthrough ixs) $$ final_branch ix
where
do_fallthrough ix =
hsep [ text "case" , pprHexVal ix (wordWidth dflags) <> colon ,
text "/* fall through */" ]
final_branch ix =
hsep [ text "case" , pprHexVal ix (wordWidth dflags) <> colon ,
text "goto" , (pprBlockId ident) <> semi ]
caseify (_ , _ ) = panic "pprSwitch: switch with no cases!"
def | Just l <- mbdef = text "default: goto" <+> pprBlockId l <> semi
| otherwise = empty
-- ---------------------------------------------------------------------
-- Expressions.
--
-- C Types: the invariant is that the C expression generated by
--
-- pprExpr e
--
-- has a type in C which is also given by
--
-- machRepCType (cmmExprType e)
--
-- (similar invariants apply to the rest of the pretty printer).
pprExpr :: CmmExpr -> SDoc
pprExpr e = case e of
CmmLit lit -> pprLit lit
CmmLoad e ty -> sdocWithDynFlags $ \dflags -> pprLoad dflags e ty
CmmReg reg -> pprCastReg reg
CmmRegOff reg 0 -> pprCastReg reg
CmmRegOff reg i
| i < 0 && negate_ok -> pprRegOff (char '-') (-i)
| otherwise -> pprRegOff (char '+') i
where
pprRegOff op i' = pprCastReg reg <> op <> int i'
negate_ok = negate (fromIntegral i :: Integer) <
fromIntegral (maxBound::Int)
-- overflow is undefined; see #7620
CmmMachOp mop args -> pprMachOpApp mop args
CmmStackSlot _ _ -> panic "pprExpr: CmmStackSlot not supported!"
pprLoad :: DynFlags -> CmmExpr -> CmmType -> SDoc
pprLoad dflags e ty
| width == W64, wordWidth dflags /= W64
= (if isFloatType ty then text "PK_DBL"
else text "PK_Word64")
<> parens (mkP_ <> pprExpr1 e)
| otherwise
= case e of
CmmReg r | isPtrReg r && width == wordWidth dflags && not (isFloatType ty)
-> char '*' <> pprAsPtrReg r
CmmRegOff r 0 | isPtrReg r && width == wordWidth dflags && not (isFloatType ty)
-> char '*' <> pprAsPtrReg r
CmmRegOff r off | isPtrReg r && width == wordWidth dflags
, off `rem` wORD_SIZE dflags == 0 && not (isFloatType ty)
-- ToDo: check that the offset is a word multiple?
-- (For tagging to work, I had to avoid unaligned loads. --ARY)
-> pprAsPtrReg r <> brackets (ppr (off `shiftR` wordShift dflags))
_other -> cLoad e ty
where
width = typeWidth ty
pprExpr1 :: CmmExpr -> SDoc
pprExpr1 (CmmLit lit) = pprLit1 lit
pprExpr1 e@(CmmReg _reg) = pprExpr e
pprExpr1 other = parens (pprExpr other)
-- --------------------------------------------------------------------------
-- MachOp applications
pprMachOpApp :: MachOp -> [CmmExpr] -> SDoc
pprMachOpApp op args
| isMulMayOfloOp op
= text "mulIntMayOflo" <> parens (commafy (map pprExpr args))
where isMulMayOfloOp (MO_U_MulMayOflo _) = True
isMulMayOfloOp (MO_S_MulMayOflo _) = True
isMulMayOfloOp _ = False
pprMachOpApp mop args
| Just ty <- machOpNeedsCast mop
= ty <> parens (pprMachOpApp' mop args)
| otherwise
= pprMachOpApp' mop args
-- Comparisons in C have type 'int', but we want type W_ (this is what
-- resultRepOfMachOp says). The other C operations inherit their type
-- from their operands, so no casting is required.
machOpNeedsCast :: MachOp -> Maybe SDoc
machOpNeedsCast mop
| isComparisonMachOp mop = Just mkW_
| otherwise = Nothing
pprMachOpApp' :: MachOp -> [CmmExpr] -> SDoc
pprMachOpApp' mop args
= case args of
-- dyadic
[x,y] -> pprArg x <+> pprMachOp_for_C mop <+> pprArg y
-- unary
[x] -> pprMachOp_for_C mop <> parens (pprArg x)
_ -> panic "PprC.pprMachOp : machop with wrong number of args"
where
-- Cast needed for signed integer ops
pprArg e | signedOp mop = sdocWithDynFlags $ \dflags ->
cCast (machRep_S_CType (typeWidth (cmmExprType dflags e))) e
| needsFCasts mop = sdocWithDynFlags $ \dflags ->
cCast (machRep_F_CType (typeWidth (cmmExprType dflags e))) e
| otherwise = pprExpr1 e
needsFCasts (MO_F_Eq _) = False
needsFCasts (MO_F_Ne _) = False
needsFCasts (MO_F_Neg _) = True
needsFCasts (MO_F_Quot _) = True
needsFCasts mop = floatComparison mop
-- --------------------------------------------------------------------------
-- Literals
pprLit :: CmmLit -> SDoc
pprLit lit = case lit of
CmmInt i rep -> pprHexVal i rep
CmmFloat f w -> parens (machRep_F_CType w) <> str
where d = fromRational f :: Double
str | isInfinite d && d < 0 = text "-INFINITY"
| isInfinite d = text "INFINITY"
| isNaN d = text "NAN"
| otherwise = text (show d)
-- these constants come from <math.h>
-- see #1861
CmmVec {} -> panic "PprC printing vector literal"
CmmBlock bid -> mkW_ <> pprCLabelAddr (infoTblLbl bid)
CmmHighStackMark -> panic "PprC printing high stack mark"
CmmLabel clbl -> mkW_ <> pprCLabelAddr clbl
CmmLabelOff clbl i -> mkW_ <> pprCLabelAddr clbl <> char '+' <> int i
CmmLabelDiffOff clbl1 _ i
-- WARNING:
-- * the lit must occur in the info table clbl2
-- * clbl1 must be an SRT, a slow entry point or a large bitmap
-> mkW_ <> pprCLabelAddr clbl1 <> char '+' <> int i
where
pprCLabelAddr lbl = char '&' <> ppr lbl
pprLit1 :: CmmLit -> SDoc
pprLit1 lit@(CmmLabelOff _ _) = parens (pprLit lit)
pprLit1 lit@(CmmLabelDiffOff _ _ _) = parens (pprLit lit)
pprLit1 lit@(CmmFloat _ _) = parens (pprLit lit)
pprLit1 other = pprLit other
-- ---------------------------------------------------------------------------
-- Static data
pprStatics :: DynFlags -> [CmmStatic] -> [SDoc]
pprStatics _ [] = []
pprStatics dflags (CmmStaticLit (CmmFloat f W32) : rest)
-- floats are padded to a word by padLitToWord, see #1852
| wORD_SIZE dflags == 8, CmmStaticLit (CmmInt 0 W32) : rest' <- rest
= pprLit1 (floatToWord dflags f) : pprStatics dflags rest'
| wORD_SIZE dflags == 4
= pprLit1 (floatToWord dflags f) : pprStatics dflags rest
| otherwise
= pprPanic "pprStatics: float" (vcat (map ppr' rest))
where ppr' (CmmStaticLit l) = sdocWithDynFlags $ \dflags ->
ppr (cmmLitType dflags l)
ppr' _other = text "bad static!"
pprStatics dflags (CmmStaticLit (CmmFloat f W64) : rest)
= map pprLit1 (doubleToWords dflags f) ++ pprStatics dflags rest
pprStatics dflags (CmmStaticLit (CmmInt i W64) : rest)
| wordWidth dflags == W32
= if wORDS_BIGENDIAN dflags
then pprStatics dflags (CmmStaticLit (CmmInt q W32) :
CmmStaticLit (CmmInt r W32) : rest)
else pprStatics dflags (CmmStaticLit (CmmInt r W32) :
CmmStaticLit (CmmInt q W32) : rest)
where r = i .&. 0xffffffff
q = i `shiftR` 32
pprStatics dflags (CmmStaticLit (CmmInt _ w) : _)
| w /= wordWidth dflags
= panic "pprStatics: cannot emit a non-word-sized static literal"
pprStatics dflags (CmmStaticLit lit : rest)
= pprLit1 lit : pprStatics dflags rest
pprStatics _ (other : _)
= pprPanic "pprWord" (pprStatic other)
pprStatic :: CmmStatic -> SDoc
pprStatic s = case s of
CmmStaticLit lit -> nest 4 (pprLit lit)
CmmUninitialised i -> nest 4 (mkC_ <> brackets (int i))
-- these should be inlined, like the old .hc
CmmString s' -> nest 4 (mkW_ <> parens(pprStringInCStyle s'))
-- ---------------------------------------------------------------------------
-- Block Ids
pprBlockId :: BlockId -> SDoc
pprBlockId b = char '_' <> ppr (getUnique b)
-- --------------------------------------------------------------------------
-- Print a MachOp in a way suitable for emitting via C.
--
pprMachOp_for_C :: MachOp -> SDoc
pprMachOp_for_C mop = case mop of
-- Integer operations
MO_Add _ -> char '+'
MO_Sub _ -> char '-'
MO_Eq _ -> text "=="
MO_Ne _ -> text "!="
MO_Mul _ -> char '*'
MO_S_Quot _ -> char '/'
MO_S_Rem _ -> char '%'
MO_S_Neg _ -> char '-'
MO_U_Quot _ -> char '/'
MO_U_Rem _ -> char '%'
-- & Floating-point operations
MO_F_Add _ -> char '+'
MO_F_Sub _ -> char '-'
MO_F_Neg _ -> char '-'
MO_F_Mul _ -> char '*'
MO_F_Quot _ -> char '/'
-- Signed comparisons
MO_S_Ge _ -> text ">="
MO_S_Le _ -> text "<="
MO_S_Gt _ -> char '>'
MO_S_Lt _ -> char '<'
-- & Unsigned comparisons
MO_U_Ge _ -> text ">="
MO_U_Le _ -> text "<="
MO_U_Gt _ -> char '>'
MO_U_Lt _ -> char '<'
-- & Floating-point comparisons
MO_F_Eq _ -> text "=="
MO_F_Ne _ -> text "!="
MO_F_Ge _ -> text ">="
MO_F_Le _ -> text "<="
MO_F_Gt _ -> char '>'
MO_F_Lt _ -> char '<'
-- Bitwise operations. Not all of these may be supported at all
-- sizes, and only integral MachReps are valid.
MO_And _ -> char '&'
MO_Or _ -> char '|'
MO_Xor _ -> char '^'
MO_Not _ -> char '~'
MO_Shl _ -> text "<<"
MO_U_Shr _ -> text ">>" -- unsigned shift right
MO_S_Shr _ -> text ">>" -- signed shift right
-- Conversions. Some of these will be NOPs, but never those that convert
-- between ints and floats.
-- Floating-point conversions use the signed variant.
-- We won't know to generate (void*) casts here, but maybe from
-- context elsewhere
-- noop casts
MO_UU_Conv from to | from == to -> empty
MO_UU_Conv _from to -> parens (machRep_U_CType to)
MO_SS_Conv from to | from == to -> empty
MO_SS_Conv _from to -> parens (machRep_S_CType to)
MO_FF_Conv from to | from == to -> empty
MO_FF_Conv _from to -> parens (machRep_F_CType to)
MO_SF_Conv _from to -> parens (machRep_F_CType to)
MO_FS_Conv _from to -> parens (machRep_S_CType to)
MO_S_MulMayOflo _ -> pprTrace "offending mop:"
(text "MO_S_MulMayOflo")
(panic $ "PprC.pprMachOp_for_C: MO_S_MulMayOflo"
++ " should have been handled earlier!")
MO_U_MulMayOflo _ -> pprTrace "offending mop:"
(text "MO_U_MulMayOflo")
(panic $ "PprC.pprMachOp_for_C: MO_U_MulMayOflo"
++ " should have been handled earlier!")
MO_V_Insert {} -> pprTrace "offending mop:"
(text "MO_V_Insert")
(panic $ "PprC.pprMachOp_for_C: MO_V_Insert"
++ " should have been handled earlier!")
MO_V_Extract {} -> pprTrace "offending mop:"
(text "MO_V_Extract")
(panic $ "PprC.pprMachOp_for_C: MO_V_Extract"
++ " should have been handled earlier!")
MO_V_Add {} -> pprTrace "offending mop:"
(text "MO_V_Add")
(panic $ "PprC.pprMachOp_for_C: MO_V_Add"
++ " should have been handled earlier!")
MO_V_Sub {} -> pprTrace "offending mop:"
(text "MO_V_Sub")
(panic $ "PprC.pprMachOp_for_C: MO_V_Sub"
++ " should have been handled earlier!")
MO_V_Mul {} -> pprTrace "offending mop:"
(text "MO_V_Mul")
(panic $ "PprC.pprMachOp_for_C: MO_V_Mul"
++ " should have been handled earlier!")
MO_VS_Quot {} -> pprTrace "offending mop:"
(text "MO_VS_Quot")
(panic $ "PprC.pprMachOp_for_C: MO_VS_Quot"
++ " should have been handled earlier!")
MO_VS_Rem {} -> pprTrace "offending mop:"
(text "MO_VS_Rem")
(panic $ "PprC.pprMachOp_for_C: MO_VS_Rem"
++ " should have been handled earlier!")
MO_VS_Neg {} -> pprTrace "offending mop:"
(text "MO_VS_Neg")
(panic $ "PprC.pprMachOp_for_C: MO_VS_Neg"
++ " should have been handled earlier!")
MO_VU_Quot {} -> pprTrace "offending mop:"
(text "MO_VU_Quot")
(panic $ "PprC.pprMachOp_for_C: MO_VU_Quot"
++ " should have been handled earlier!")
MO_VU_Rem {} -> pprTrace "offending mop:"
(text "MO_VU_Rem")
(panic $ "PprC.pprMachOp_for_C: MO_VU_Rem"
++ " should have been handled earlier!")
MO_VF_Insert {} -> pprTrace "offending mop:"
(text "MO_VF_Insert")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Insert"
++ " should have been handled earlier!")
MO_VF_Extract {} -> pprTrace "offending mop:"
(text "MO_VF_Extract")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Extract"
++ " should have been handled earlier!")
MO_VF_Add {} -> pprTrace "offending mop:"
(text "MO_VF_Add")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Add"
++ " should have been handled earlier!")
MO_VF_Sub {} -> pprTrace "offending mop:"
(text "MO_VF_Sub")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Sub"
++ " should have been handled earlier!")
MO_VF_Neg {} -> pprTrace "offending mop:"
(text "MO_VF_Neg")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Neg"
++ " should have been handled earlier!")
MO_VF_Mul {} -> pprTrace "offending mop:"
(text "MO_VF_Mul")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Mul"
++ " should have been handled earlier!")
MO_VF_Quot {} -> pprTrace "offending mop:"
(text "MO_VF_Quot")
(panic $ "PprC.pprMachOp_for_C: MO_VF_Quot"
++ " should have been handled earlier!")
signedOp :: MachOp -> Bool -- Argument type(s) are signed ints
signedOp (MO_S_Quot _) = True
signedOp (MO_S_Rem _) = True
signedOp (MO_S_Neg _) = True
signedOp (MO_S_Ge _) = True
signedOp (MO_S_Le _) = True
signedOp (MO_S_Gt _) = True
signedOp (MO_S_Lt _) = True
signedOp (MO_S_Shr _) = True
signedOp (MO_SS_Conv _ _) = True
signedOp (MO_SF_Conv _ _) = True
signedOp _ = False
floatComparison :: MachOp -> Bool -- comparison between float args
floatComparison (MO_F_Eq _) = True
floatComparison (MO_F_Ne _) = True
floatComparison (MO_F_Ge _) = True
floatComparison (MO_F_Le _) = True
floatComparison (MO_F_Gt _) = True
floatComparison (MO_F_Lt _) = True
floatComparison _ = False
-- ---------------------------------------------------------------------
-- tend to be implemented by foreign calls
pprCallishMachOp_for_C :: CallishMachOp -> SDoc
pprCallishMachOp_for_C mop
= case mop of
MO_F64_Pwr -> text "pow"
MO_F64_Sin -> text "sin"
MO_F64_Cos -> text "cos"
MO_F64_Tan -> text "tan"
MO_F64_Sinh -> text "sinh"
MO_F64_Cosh -> text "cosh"
MO_F64_Tanh -> text "tanh"
MO_F64_Asin -> text "asin"
MO_F64_Acos -> text "acos"
MO_F64_Atan -> text "atan"
MO_F64_Log -> text "log"
MO_F64_Exp -> text "exp"
MO_F64_Sqrt -> text "sqrt"
MO_F64_Fabs -> text "fabs"
MO_F32_Pwr -> text "powf"
MO_F32_Sin -> text "sinf"
MO_F32_Cos -> text "cosf"
MO_F32_Tan -> text "tanf"
MO_F32_Sinh -> text "sinhf"
MO_F32_Cosh -> text "coshf"
MO_F32_Tanh -> text "tanhf"
MO_F32_Asin -> text "asinf"
MO_F32_Acos -> text "acosf"
MO_F32_Atan -> text "atanf"
MO_F32_Log -> text "logf"
MO_F32_Exp -> text "expf"
MO_F32_Sqrt -> text "sqrtf"
MO_F32_Fabs -> text "fabsf"
MO_WriteBarrier -> text "write_barrier"
MO_Memcpy _ -> text "memcpy"
MO_Memset _ -> text "memset"
MO_Memmove _ -> text "memmove"
(MO_BSwap w) -> ptext (sLit $ bSwapLabel w)
(MO_PopCnt w) -> ptext (sLit $ popCntLabel w)
(MO_Clz w) -> ptext (sLit $ clzLabel w)
(MO_Ctz w) -> ptext (sLit $ ctzLabel w)
(MO_AtomicRMW w amop) -> ptext (sLit $ atomicRMWLabel w amop)
(MO_Cmpxchg w) -> ptext (sLit $ cmpxchgLabel w)
(MO_AtomicRead w) -> ptext (sLit $ atomicReadLabel w)
(MO_AtomicWrite w) -> ptext (sLit $ atomicWriteLabel w)
(MO_UF_Conv w) -> ptext (sLit $ word2FloatLabel w)
MO_S_QuotRem {} -> unsupported
MO_U_QuotRem {} -> unsupported
MO_U_QuotRem2 {} -> unsupported
MO_Add2 {} -> unsupported
MO_SubWordC {} -> unsupported
MO_AddIntC {} -> unsupported
MO_SubIntC {} -> unsupported
MO_U_Mul2 {} -> unsupported
MO_Touch -> unsupported
(MO_Prefetch_Data _ ) -> unsupported
--- we could support prefetch via "__builtin_prefetch"
--- Not adding it for now
where unsupported = panic ("pprCallishMachOp_for_C: " ++ show mop
++ " not supported!")
-- ---------------------------------------------------------------------
-- Useful #defines
--
mkJMP_, mkFN_, mkIF_ :: SDoc -> SDoc
mkJMP_ i = text "JMP_" <> parens i
mkFN_ i = text "FN_" <> parens i -- externally visible function
mkIF_ i = text "IF_" <> parens i -- locally visible
-- from includes/Stg.h
--
mkC_,mkW_,mkP_ :: SDoc
mkC_ = text "(C_)" -- StgChar
mkW_ = text "(W_)" -- StgWord
mkP_ = text "(P_)" -- StgWord*
-- ---------------------------------------------------------------------
--
-- Assignments
--
-- Generating assignments is what we're all about, here
--
pprAssign :: DynFlags -> CmmReg -> CmmExpr -> SDoc
-- dest is a reg, rhs is a reg
pprAssign _ r1 (CmmReg r2)
| isPtrReg r1 && isPtrReg r2
= hcat [ pprAsPtrReg r1, equals, pprAsPtrReg r2, semi ]
-- dest is a reg, rhs is a CmmRegOff
pprAssign dflags r1 (CmmRegOff r2 off)
| isPtrReg r1 && isPtrReg r2 && (off `rem` wORD_SIZE dflags == 0)
= hcat [ pprAsPtrReg r1, equals, pprAsPtrReg r2, op, int off', semi ]
where
off1 = off `shiftR` wordShift dflags
(op,off') | off >= 0 = (char '+', off1)
| otherwise = (char '-', -off1)
-- dest is a reg, rhs is anything.
-- We can't cast the lvalue, so we have to cast the rhs if necessary. Casting
-- the lvalue elicits a warning from new GCC versions (3.4+).
pprAssign _ r1 r2
| isFixedPtrReg r1 = mkAssign (mkP_ <> pprExpr1 r2)
| Just ty <- strangeRegType r1 = mkAssign (parens ty <> pprExpr1 r2)
| otherwise = mkAssign (pprExpr r2)
where mkAssign x = if r1 == CmmGlobal BaseReg
then text "ASSIGN_BaseReg" <> parens x <> semi
else pprReg r1 <> text " = " <> x <> semi
-- ---------------------------------------------------------------------
-- Registers
pprCastReg :: CmmReg -> SDoc
pprCastReg reg
| isStrangeTypeReg reg = mkW_ <> pprReg reg
| otherwise = pprReg reg
-- True if (pprReg reg) will give an expression with type StgPtr. We
-- need to take care with pointer arithmetic on registers with type
-- StgPtr.
isFixedPtrReg :: CmmReg -> Bool
isFixedPtrReg (CmmLocal _) = False
isFixedPtrReg (CmmGlobal r) = isFixedPtrGlobalReg r
-- True if (pprAsPtrReg reg) will give an expression with type StgPtr
-- JD: THIS IS HORRIBLE AND SHOULD BE RENAMED, AT THE VERY LEAST.
-- THE GARBAGE WITH THE VNonGcPtr HELPS MATCH THE OLD CODE GENERATOR'S OUTPUT;
-- I'M NOT SURE IF IT SHOULD REALLY STAY THAT WAY.
isPtrReg :: CmmReg -> Bool
isPtrReg (CmmLocal _) = False
isPtrReg (CmmGlobal (VanillaReg _ VGcPtr)) = True -- if we print via pprAsPtrReg
isPtrReg (CmmGlobal (VanillaReg _ VNonGcPtr)) = False -- if we print via pprAsPtrReg
isPtrReg (CmmGlobal reg) = isFixedPtrGlobalReg reg
-- True if this global reg has type StgPtr
isFixedPtrGlobalReg :: GlobalReg -> Bool
isFixedPtrGlobalReg Sp = True
isFixedPtrGlobalReg Hp = True
isFixedPtrGlobalReg HpLim = True
isFixedPtrGlobalReg SpLim = True
isFixedPtrGlobalReg _ = False
-- True if in C this register doesn't have the type given by
-- (machRepCType (cmmRegType reg)), so it has to be cast.
isStrangeTypeReg :: CmmReg -> Bool
isStrangeTypeReg (CmmLocal _) = False
isStrangeTypeReg (CmmGlobal g) = isStrangeTypeGlobal g
isStrangeTypeGlobal :: GlobalReg -> Bool
isStrangeTypeGlobal CCCS = True
isStrangeTypeGlobal CurrentTSO = True
isStrangeTypeGlobal CurrentNursery = True
isStrangeTypeGlobal BaseReg = True
isStrangeTypeGlobal r = isFixedPtrGlobalReg r
strangeRegType :: CmmReg -> Maybe SDoc
strangeRegType (CmmGlobal CCCS) = Just (text "struct CostCentreStack_ *")
strangeRegType (CmmGlobal CurrentTSO) = Just (text "struct StgTSO_ *")
strangeRegType (CmmGlobal CurrentNursery) = Just (text "struct bdescr_ *")
strangeRegType (CmmGlobal BaseReg) = Just (text "struct StgRegTable_ *")
strangeRegType _ = Nothing
-- pprReg just prints the register name.
--
pprReg :: CmmReg -> SDoc
pprReg r = case r of
CmmLocal local -> pprLocalReg local
CmmGlobal global -> pprGlobalReg global
pprAsPtrReg :: CmmReg -> SDoc
pprAsPtrReg (CmmGlobal (VanillaReg n gcp))
= WARN( gcp /= VGcPtr, ppr n ) char 'R' <> int n <> text ".p"
pprAsPtrReg other_reg = pprReg other_reg
pprGlobalReg :: GlobalReg -> SDoc
pprGlobalReg gr = case gr of
VanillaReg n _ -> char 'R' <> int n <> text ".w"
-- pprGlobalReg prints a VanillaReg as a .w regardless
-- Example: R1.w = R1.w & (-0x8UL);
-- JMP_(*R1.p);
FloatReg n -> char 'F' <> int n
DoubleReg n -> char 'D' <> int n
LongReg n -> char 'L' <> int n
Sp -> text "Sp"
SpLim -> text "SpLim"
Hp -> text "Hp"
HpLim -> text "HpLim"
CCCS -> text "CCCS"
CurrentTSO -> text "CurrentTSO"
CurrentNursery -> text "CurrentNursery"
HpAlloc -> text "HpAlloc"
BaseReg -> text "BaseReg"
EagerBlackholeInfo -> text "stg_EAGER_BLACKHOLE_info"
GCEnter1 -> text "stg_gc_enter_1"
GCFun -> text "stg_gc_fun"
other -> panic $ "pprGlobalReg: Unsupported register: " ++ show other
pprLocalReg :: LocalReg -> SDoc
pprLocalReg (LocalReg uniq _) = char '_' <> ppr uniq
-- -----------------------------------------------------------------------------
-- Foreign Calls
pprCall :: SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual] -> SDoc
pprCall ppr_fn cconv results args
| not (is_cishCC cconv)
= panic $ "pprCall: unknown calling convention"
| otherwise
=
ppr_assign results (ppr_fn <> parens (commafy (map pprArg args))) <> semi
where
ppr_assign [] rhs = rhs
ppr_assign [(one,hint)] rhs
= pprLocalReg one <> text " = "
<> pprUnHint hint (localRegType one) <> rhs
ppr_assign _other _rhs = panic "pprCall: multiple results"
pprArg (expr, AddrHint)
= cCast (text "void *") expr
-- see comment by machRepHintCType below
pprArg (expr, SignedHint)
= sdocWithDynFlags $ \dflags ->
cCast (machRep_S_CType $ typeWidth $ cmmExprType dflags expr) expr
pprArg (expr, _other)
= pprExpr expr
pprUnHint AddrHint rep = parens (machRepCType rep)
pprUnHint SignedHint rep = parens (machRepCType rep)
pprUnHint _ _ = empty
-- Currently we only have these two calling conventions, but this might
-- change in the future...
is_cishCC :: CCallConv -> Bool
is_cishCC CCallConv = True
is_cishCC CApiConv = True
is_cishCC StdCallConv = True
is_cishCC PrimCallConv = False
is_cishCC JavaScriptCallConv = False
-- ---------------------------------------------------------------------
-- Find and print local and external declarations for a list of
-- Cmm statements.
--
pprTempAndExternDecls :: [CmmBlock] -> (SDoc{-temps-}, SDoc{-externs-})
pprTempAndExternDecls stmts
= (pprUFM (getUniqSet temps) (vcat . map pprTempDecl),
vcat (map (pprExternDecl False{-ToDo-}) (Map.keys lbls)))
where (temps, lbls) = runTE (mapM_ te_BB stmts)
pprDataExterns :: [CmmStatic] -> SDoc
pprDataExterns statics
= vcat (map (pprExternDecl False{-ToDo-}) (Map.keys lbls))
where (_, lbls) = runTE (mapM_ te_Static statics)
pprTempDecl :: LocalReg -> SDoc
pprTempDecl l@(LocalReg _ rep)
= hcat [ machRepCType rep, space, pprLocalReg l, semi ]
pprExternDecl :: Bool -> CLabel -> SDoc
pprExternDecl _in_srt lbl
-- do not print anything for "known external" things
| not (needsCDecl lbl) = empty
| Just sz <- foreignLabelStdcallInfo lbl = stdcall_decl sz
| otherwise =
hcat [ visibility, label_type lbl,
lparen, ppr lbl, text ");" ]
where
label_type lbl | isBytesLabel lbl = text "B_"
| isForeignLabel lbl && isCFunctionLabel lbl = text "FF_"
| isCFunctionLabel lbl = text "F_"
| otherwise = text "I_"
visibility
| externallyVisibleCLabel lbl = char 'E'
| otherwise = char 'I'
-- If the label we want to refer to is a stdcall function (on Windows) then
-- we must generate an appropriate prototype for it, so that the C compiler will
-- add the @n suffix to the label (#2276)
stdcall_decl sz = sdocWithDynFlags $ \dflags ->
text "extern __attribute__((stdcall)) void " <> ppr lbl
<> parens (commafy (replicate (sz `quot` wORD_SIZE dflags) (machRep_U_CType (wordWidth dflags))))
<> semi
type TEState = (UniqSet LocalReg, Map CLabel ())
newtype TE a = TE { unTE :: TEState -> (a, TEState) }
instance Functor TE where
fmap = liftM
instance Applicative TE where
pure a = TE $ \s -> (a, s)
(<*>) = ap
instance Monad TE where
TE m >>= k = TE $ \s -> case m s of (a, s') -> unTE (k a) s'
te_lbl :: CLabel -> TE ()
te_lbl lbl = TE $ \(temps,lbls) -> ((), (temps, Map.insert lbl () lbls))
te_temp :: LocalReg -> TE ()
te_temp r = TE $ \(temps,lbls) -> ((), (addOneToUniqSet temps r, lbls))
runTE :: TE () -> TEState
runTE (TE m) = snd (m (emptyUniqSet, Map.empty))
te_Static :: CmmStatic -> TE ()
te_Static (CmmStaticLit lit) = te_Lit lit
te_Static _ = return ()
te_BB :: CmmBlock -> TE ()
te_BB block = mapM_ te_Stmt (blockToList mid) >> te_Stmt last
where (_, mid, last) = blockSplit block
te_Lit :: CmmLit -> TE ()
te_Lit (CmmLabel l) = te_lbl l
te_Lit (CmmLabelOff l _) = te_lbl l
te_Lit (CmmLabelDiffOff l1 _ _) = te_lbl l1
te_Lit _ = return ()
te_Stmt :: CmmNode e x -> TE ()
te_Stmt (CmmAssign r e) = te_Reg r >> te_Expr e
te_Stmt (CmmStore l r) = te_Expr l >> te_Expr r
te_Stmt (CmmUnsafeForeignCall target rs es)
= do te_Target target
mapM_ te_temp rs
mapM_ te_Expr es
te_Stmt (CmmCondBranch e _ _ _) = te_Expr e
te_Stmt (CmmSwitch e _) = te_Expr e
te_Stmt (CmmCall { cml_target = e }) = te_Expr e
te_Stmt _ = return ()
te_Target :: ForeignTarget -> TE ()
te_Target (ForeignTarget e _) = te_Expr e
te_Target (PrimTarget{}) = return ()
te_Expr :: CmmExpr -> TE ()
te_Expr (CmmLit lit) = te_Lit lit
te_Expr (CmmLoad e _) = te_Expr e
te_Expr (CmmReg r) = te_Reg r
te_Expr (CmmMachOp _ es) = mapM_ te_Expr es
te_Expr (CmmRegOff r _) = te_Reg r
te_Expr (CmmStackSlot _ _) = panic "te_Expr: CmmStackSlot not supported!"
te_Reg :: CmmReg -> TE ()
te_Reg (CmmLocal l) = te_temp l
te_Reg _ = return ()
-- ---------------------------------------------------------------------
-- C types for MachReps
cCast :: SDoc -> CmmExpr -> SDoc
cCast ty expr = parens ty <> pprExpr1 expr
cLoad :: CmmExpr -> CmmType -> SDoc
cLoad expr rep
= sdocWithPlatform $ \platform ->
if bewareLoadStoreAlignment (platformArch platform)
then let decl = machRepCType rep <+> text "x" <> semi
struct = text "struct" <+> braces (decl)
packed_attr = text "__attribute__((packed))"
cast = parens (struct <+> packed_attr <> char '*')
in parens (cast <+> pprExpr1 expr) <> text "->x"
else char '*' <> parens (cCast (machRepPtrCType rep) expr)
where -- On these platforms, unaligned loads are known to cause problems
bewareLoadStoreAlignment ArchAlpha = True
bewareLoadStoreAlignment ArchMipseb = True
bewareLoadStoreAlignment ArchMipsel = True
bewareLoadStoreAlignment (ArchARM {}) = True
bewareLoadStoreAlignment ArchARM64 = True
bewareLoadStoreAlignment ArchSPARC = True
bewareLoadStoreAlignment ArchSPARC64 = True
-- Pessimistically assume that they will also cause problems
-- on unknown arches
bewareLoadStoreAlignment ArchUnknown = True
bewareLoadStoreAlignment _ = False
isCmmWordType :: DynFlags -> CmmType -> Bool
-- True of GcPtrReg/NonGcReg of native word size
isCmmWordType dflags ty = not (isFloatType ty)
&& typeWidth ty == wordWidth dflags
-- This is for finding the types of foreign call arguments. For a pointer
-- argument, we always cast the argument to (void *), to avoid warnings from
-- the C compiler.
machRepHintCType :: CmmType -> ForeignHint -> SDoc
machRepHintCType _ AddrHint = text "void *"
machRepHintCType rep SignedHint = machRep_S_CType (typeWidth rep)
machRepHintCType rep _other = machRepCType rep
machRepPtrCType :: CmmType -> SDoc
machRepPtrCType r
= sdocWithDynFlags $ \dflags ->
if isCmmWordType dflags r then text "P_"
else machRepCType r <> char '*'
machRepCType :: CmmType -> SDoc
machRepCType ty | isFloatType ty = machRep_F_CType w
| otherwise = machRep_U_CType w
where
w = typeWidth ty
machRep_F_CType :: Width -> SDoc
machRep_F_CType W32 = text "StgFloat" -- ToDo: correct?
machRep_F_CType W64 = text "StgDouble"
machRep_F_CType _ = panic "machRep_F_CType"
machRep_U_CType :: Width -> SDoc
machRep_U_CType w
= sdocWithDynFlags $ \dflags ->
case w of
_ | w == wordWidth dflags -> text "W_"
W8 -> text "StgWord8"
W16 -> text "StgWord16"
W32 -> text "StgWord32"
W64 -> text "StgWord64"
_ -> panic "machRep_U_CType"
machRep_S_CType :: Width -> SDoc
machRep_S_CType w
= sdocWithDynFlags $ \dflags ->
case w of
_ | w == wordWidth dflags -> text "I_"
W8 -> text "StgInt8"
W16 -> text "StgInt16"
W32 -> text "StgInt32"
W64 -> text "StgInt64"
_ -> panic "machRep_S_CType"
-- ---------------------------------------------------------------------
-- print strings as valid C strings
pprStringInCStyle :: [Word8] -> SDoc
pprStringInCStyle s = doubleQuotes (text (concatMap charToC s))
-- ---------------------------------------------------------------------------
-- Initialising static objects with floating-point numbers. We can't
-- just emit the floating point number, because C will cast it to an int
-- by rounding it. We want the actual bit-representation of the float.
--
-- Consider a concrete C example:
-- double d = 2.5e-10;
-- float f = 2.5e-10f;
--
-- int * i2 = &d; printf ("i2: %08X %08X\n", i2[0], i2[1]);
-- long long * l = &d; printf (" l: %016llX\n", l[0]);
-- int * i = &f; printf (" i: %08X\n", i[0]);
-- Result on 64-bit LE (x86_64):
-- i2: E826D695 3DF12E0B
-- l: 3DF12E0BE826D695
-- i: 2F89705F
-- Result on 32-bit BE (m68k):
-- i2: 3DF12E0B E826D695
-- l: 3DF12E0BE826D695
-- i: 2F89705F
--
-- The trick here is to notice that binary representation does not
-- change much: only Word32 values get swapped on LE hosts / targets.
-- This is a hack to turn the floating point numbers into ints that we
-- can safely initialise to static locations.
castFloatToWord32Array :: STUArray s Int Float -> ST s (STUArray s Int Word32)
castFloatToWord32Array = U.castSTUArray
castDoubleToWord64Array :: STUArray s Int Double -> ST s (STUArray s Int Word64)
castDoubleToWord64Array = U.castSTUArray
floatToWord :: DynFlags -> Rational -> CmmLit
floatToWord dflags r
= runST (do
arr <- newArray_ ((0::Int),0)
writeArray arr 0 (fromRational r)
arr' <- castFloatToWord32Array arr
w32 <- readArray arr' 0
return (CmmInt (toInteger w32 `shiftL` wo) (wordWidth dflags))
)
where wo | wordWidth dflags == W64
, wORDS_BIGENDIAN dflags = 32
| otherwise = 0
doubleToWords :: DynFlags -> Rational -> [CmmLit]
doubleToWords dflags r
= runST (do
arr <- newArray_ ((0::Int),1)
writeArray arr 0 (fromRational r)
arr' <- castDoubleToWord64Array arr
w64 <- readArray arr' 0
return (pprWord64 w64)
)
where targetWidth = wordWidth dflags
targetBE = wORDS_BIGENDIAN dflags
pprWord64 w64
| targetWidth == W64 =
[ CmmInt (toInteger w64) targetWidth ]
| targetWidth == W32 =
[ CmmInt (toInteger targetW1) targetWidth
, CmmInt (toInteger targetW2) targetWidth
]
| otherwise = panic "doubleToWords.pprWord64"
where (targetW1, targetW2)
| targetBE = (wHi, wLo)
| otherwise = (wLo, wHi)
wHi = w64 `shiftR` 32
wLo = w64 .&. 0xFFFFffff
-- ---------------------------------------------------------------------------
-- Utils
wordShift :: DynFlags -> Int
wordShift dflags = widthInLog (wordWidth dflags)
commafy :: [SDoc] -> SDoc
commafy xs = hsep $ punctuate comma xs
-- Print in C hex format: 0x13fa
pprHexVal :: Integer -> Width -> SDoc
pprHexVal w rep
| w < 0 = parens (char '-' <>
text "0x" <> intToDoc (-w) <> repsuffix rep)
| otherwise = text "0x" <> intToDoc w <> repsuffix rep
where
-- type suffix for literals:
-- Integer literals are unsigned in Cmm/C. We explicitly cast to
-- signed values for doing signed operations, but at all other
-- times values are unsigned. This also helps eliminate occasional
-- warnings about integer overflow from gcc.
repsuffix W64 = sdocWithDynFlags $ \dflags ->
if cINT_SIZE dflags == 8 then char 'U'
else if cLONG_SIZE dflags == 8 then text "UL"
else if cLONG_LONG_SIZE dflags == 8 then text "ULL"
else panic "pprHexVal: Can't find a 64-bit type"
repsuffix _ = char 'U'
intToDoc :: Integer -> SDoc
intToDoc i = case truncInt i of
0 -> char '0'
v -> go v
-- We need to truncate value as Cmm backend does not drop
-- redundant bits to ease handling of negative values.
-- Thus the following Cmm code on 64-bit arch, like amd64:
-- CInt v;
-- v = {something};
-- if (v == %lobits32(-1)) { ...
-- leads to the following C code:
-- StgWord64 v = (StgWord32)({something});
-- if (v == 0xFFFFffffFFFFffffU) { ...
-- Such code is incorrect as it promotes both operands to StgWord64
-- and the whole condition is always false.
truncInt :: Integer -> Integer
truncInt i =
case rep of
W8 -> i `rem` (2^(8 :: Int))
W16 -> i `rem` (2^(16 :: Int))
W32 -> i `rem` (2^(32 :: Int))
W64 -> i `rem` (2^(64 :: Int))
_ -> panic ("pprHexVal/truncInt: C backend can't encode "
++ show rep ++ " literals")
go 0 = empty
go w' = go q <> dig
where
(q,r) = w' `quotRem` 16
dig | r < 10 = char (chr (fromInteger r + ord '0'))
| otherwise = char (chr (fromInteger r - 10 + ord 'a'))