{-# LANGUAGE CPP #-} {-# LANGUAGE DeriveFunctor #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE LambdaCase #-} ----------------------------------------------------------------------------- -- -- 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/ppr-c -- -- 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 GHC.CmmToC ( cmmToC ) where #include "HsVersions.h" -- Cmm stuff import GHC.Prelude import GHC.Cmm.BlockId import GHC.Cmm.CLabel import GHC.Types.ForeignCall import GHC.Cmm hiding (pprBBlock) import GHC.Cmm.Ppr () -- For Outputable instances import GHC.Cmm.Dataflow.Block import GHC.Cmm.Dataflow.Collections import GHC.Cmm.Dataflow.Graph import GHC.Cmm.Utils import GHC.Cmm.Switch -- Utils import GHC.CmmToAsm.CPrim import GHC.Driver.Session import GHC.Driver.Ppr import GHC.Utils.Outputable import GHC.Utils.Panic import GHC.Platform import GHC.Types.Unique.Set import GHC.Types.Unique.FM import GHC.Types.Unique import GHC.Utils.Misc -- The rest import Data.ByteString (ByteString) import qualified Data.ByteString as BS import Control.Monad.ST import Data.Char import Data.List (intersperse) import Data.Map (Map) import Data.Word import qualified Data.Map as Map import Control.Monad (ap) import qualified Data.Array.Unsafe as U ( castSTUArray ) import Data.Array.ST -- -------------------------------------------------------------------------- -- Now do some real work -- -- for fun, we could call cmmToCmm over the tops... -- cmmToC :: Platform -> RawCmmGroup -> SDoc cmmToC platform tops = (vcat $ intersperse blankLine $ map (pprTop platform) tops) $$ blankLine -- -- top level procs -- pprTop :: Platform -> RawCmmDecl -> SDoc pprTop platform = \case (CmmProc infos clbl _in_live_regs graph) -> (case mapLookup (g_entry graph) infos of Nothing -> empty Just (CmmStaticsRaw info_clbl info_dat) -> pprDataExterns platform info_dat $$ pprWordArray platform info_is_in_rodata info_clbl info_dat) $$ (vcat [ blankLine, extern_decls, (if (externallyVisibleCLabel clbl) then mkFN_ else mkIF_) (pprCLabel platform CStyle clbl) <+> lbrace, nest 8 temp_decls, vcat (map (pprBBlock platform) blocks), rbrace ] ) where -- info tables are always in .rodata info_is_in_rodata = True blocks = toBlockListEntryFirst graph (temp_decls, extern_decls) = pprTempAndExternDecls platform blocks -- Chunks of static data. -- We only handle (a) arrays of word-sized things and (b) strings. (CmmData section (CmmStaticsRaw lbl [CmmString str])) -> pprExternDecl platform lbl $$ hcat [ pprLocalness lbl, pprConstness (isSecConstant section), text "char ", pprCLabel platform CStyle lbl, text "[] = ", pprStringInCStyle str, semi ] (CmmData section (CmmStaticsRaw lbl [CmmUninitialised size])) -> pprExternDecl platform lbl $$ hcat [ pprLocalness lbl, pprConstness (isSecConstant section), text "char ", pprCLabel platform CStyle lbl, brackets (int size), semi ] (CmmData section (CmmStaticsRaw lbl lits)) -> pprDataExterns platform lits $$ pprWordArray platform (isSecConstant section) lbl lits where isSecConstant section = case sectionProtection section of ReadOnlySection -> True WriteProtectedSection -> True _ -> False -- -------------------------------------------------------------------------- -- 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 :: Platform -> CmmBlock -> SDoc pprBBlock platform block = nest 4 (pprBlockId (entryLabel block) <> colon) $$ nest 8 (vcat (map (pprStmt platform) (blockToList nodes)) $$ pprStmt platform last) where (_, nodes, last) = blockSplit block -- -------------------------------------------------------------------------- -- Info tables. Just arrays of words. -- See codeGen/ClosureInfo, and nativeGen/PprMach pprWordArray :: Platform -> Bool -> CLabel -> [CmmStatic] -> SDoc pprWordArray platform is_ro lbl ds = -- TODO: align closures only pprExternDecl platform lbl $$ hcat [ pprLocalness lbl, pprConstness is_ro, text "StgWord" , space, pprCLabel platform CStyle lbl, text "[]" -- See Note [StgWord alignment] , pprAlignment (wordWidth platform) , text "= {" ] $$ nest 8 (commafy (staticLitsToWords platform $ toLits ds)) $$ text "};" where toLits :: [CmmStatic] -> [CmmLit] toLits = map f where f (CmmStaticLit lit) = lit f static = pprPanic "pprWordArray: Unexpected literal" (pprStatic platform static) pprAlignment :: Width -> SDoc pprAlignment words = text "__attribute__((aligned(" <> int (widthInBytes words) <> text ")))" -- Note [StgWord alignment] -- C codegen builds static closures as StgWord C arrays (pprWordArray). -- Their real C type is 'StgClosure'. Macros like UNTAG_CLOSURE assume -- pointers to 'StgClosure' are aligned at pointer size boundary: -- 4 byte boundary on 32 systems -- and 8 bytes on 64-bit systems -- see TAG_MASK and TAG_BITS definition and usage. -- -- It's a reasonable assumption also known as natural alignment. -- Although some architectures have different alignment rules. -- One of known exceptions is m68k (#11395, comment:16) where: -- __alignof__(StgWord) == 2, sizeof(StgWord) == 4 -- -- Thus we explicitly increase alignment by using -- __attribute__((aligned(4))) -- declaration. -- -- has to be static, if it isn't globally visible -- pprLocalness :: CLabel -> SDoc pprLocalness lbl | not $ externallyVisibleCLabel lbl = text "static " | otherwise = empty pprConstness :: Bool -> SDoc pprConstness is_ro | is_ro = text "const " | otherwise = empty -- -------------------------------------------------------------------------- -- Statements. -- pprStmt :: Platform -> CmmNode e x -> SDoc pprStmt platform stmt = case stmt of CmmEntry{} -> empty CmmComment _ -> empty -- (hang (text "/*") 3 (ftext s)) $$ text "*/" -- 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 platform dest src CmmStore dest src | typeWidth rep == W64 && wordWidth platform /= W64 -> (if isFloatType rep then text "ASSIGN_DBL" else text "ASSIGN_Word64") <> parens (mkP_ <> pprExpr1 platform dest <> comma <> pprExpr platform src) <> semi | otherwise -> hsep [ pprExpr platform (CmmLoad dest rep), equals, pprExpr platform src <> semi ] where rep = cmmExprType platform 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 platform (pprCFunType platform (char '*') cconv hresults hargs) fn) -- See wiki:commentary/compiler/backends/ppr-c#prototypes fnCall = case fn of CmmLit (CmmLabel lbl) | StdCallConv <- cconv -> pprCall platform (pprCLabel platform CStyle 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 platform cast_fn cconv hresults hargs <> semi | not (isMathFun lbl) -> pprForeignCall platform (pprCLabel platform CStyle lbl) cconv hresults hargs _ -> pprCall platform 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) $$ pprForeignCall platform fn cconv hresults hargs | otherwise = pprCall platform fn cconv hresults hargs CmmBranch ident -> pprBranch ident CmmCondBranch expr yes no _ -> pprCondBranch platform expr yes no CmmCall { cml_target = expr } -> mkJMP_ (pprExpr platform expr) <> semi CmmSwitch arg ids -> pprSwitch platform arg ids _other -> pprPanic "PprC.pprStmt" (pdoc platform stmt) type Hinted a = (a, ForeignHint) pprForeignCall :: Platform -> SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual] -> SDoc pprForeignCall platform fn cconv results args = fn_call where fn_call = braces ( pprCFunType platform (char '*' <> text "ghcFunPtr") cconv results args <> semi $$ text "ghcFunPtr" <+> equals <+> cast_fn <> semi $$ pprCall platform (text "ghcFunPtr") cconv results args <> semi ) cast_fn = parens (parens (pprCFunType platform (char '*') cconv results args) <> fn) pprCFunType :: Platform -> SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual] -> SDoc pprCFunType platform ppr_fn cconv ress args = let res_type [] = text "void" res_type [(one, hint)] = machRepHintCType platform (localRegType one) hint res_type _ = panic "pprCFunType: only void or 1 return value supported" arg_type (expr, hint) = machRepHintCType platform (cmmExprType platform expr) hint in res_type ress <+> parens (ccallConvAttribute cconv <> ppr_fn) <> parens (commafy (map arg_type args)) -- --------------------------------------------------------------------- -- unconditional branches pprBranch :: BlockId -> SDoc pprBranch ident = text "goto" <+> pprBlockId ident <> semi -- --------------------------------------------------------------------- -- conditional branches to local labels pprCondBranch :: Platform -> CmmExpr -> BlockId -> BlockId -> SDoc pprCondBranch platform expr yes no = hsep [ text "if" , parens (pprExpr platform expr) , text "goto", pprBlockId yes <> semi, text "else goto", pprBlockId no <> semi ] -- --------------------------------------------------------------------- -- a local table branch -- -- we find the fall-through cases -- pprSwitch :: Platform -> CmmExpr -> SwitchTargets -> SDoc pprSwitch platform e ids = (hang (text "switch" <+> parens ( pprExpr platform e ) <+> lbrace) 4 (vcat ( map caseify pairs ) $$ 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 platform ix (wordWidth platform) <> colon , text "/* fall through */" ] final_branch ix = hsep [ text "case" , pprHexVal platform ix (wordWidth platform) <> 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 :: Platform -> CmmExpr -> SDoc pprExpr platform e = case e of CmmLit lit -> pprLit platform lit CmmLoad e ty -> pprLoad platform e ty CmmReg reg -> pprCastReg reg CmmRegOff reg 0 -> pprCastReg reg -- CmmRegOff is an alias of MO_Add CmmRegOff reg i -> pprCastReg reg <> char '+' <> pprHexVal platform (fromIntegral i) (wordWidth platform) CmmMachOp mop args -> pprMachOpApp platform mop args CmmStackSlot _ _ -> panic "pprExpr: CmmStackSlot not supported!" pprLoad :: Platform -> CmmExpr -> CmmType -> SDoc pprLoad platform e ty | width == W64, wordWidth platform /= W64 = (if isFloatType ty then text "PK_DBL" else text "PK_Word64") <> parens (mkP_ <> pprExpr1 platform e) | otherwise = case e of CmmReg r | isPtrReg r && width == wordWidth platform && not (isFloatType ty) -> char '*' <> pprAsPtrReg r CmmRegOff r 0 | isPtrReg r && width == wordWidth platform && not (isFloatType ty) -> char '*' <> pprAsPtrReg r CmmRegOff r off | isPtrReg r && width == wordWidth platform , off `rem` platformWordSizeInBytes platform == 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 platform)) _other -> cLoad platform e ty where width = typeWidth ty pprExpr1 :: Platform -> CmmExpr -> SDoc pprExpr1 platform e = case e of CmmLit lit -> pprLit1 platform lit CmmReg _reg -> pprExpr platform e _ -> parens (pprExpr platform e) -- -------------------------------------------------------------------------- -- MachOp applications pprMachOpApp :: Platform -> MachOp -> [CmmExpr] -> SDoc pprMachOpApp platform op args | isMulMayOfloOp op = text "mulIntMayOflo" <> parens (commafy (map (pprExpr platform) args)) where isMulMayOfloOp (MO_U_MulMayOflo _) = True isMulMayOfloOp (MO_S_MulMayOflo _) = True isMulMayOfloOp _ = False pprMachOpApp platform mop args | Just ty <- machOpNeedsCast mop = ty <> parens (pprMachOpApp' platform mop args) | otherwise = pprMachOpApp' platform 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' :: Platform -> MachOp -> [CmmExpr] -> SDoc pprMachOpApp' platform mop args = case args of -- dyadic [x,y] -> pprArg x <+> pprMachOp_for_C platform mop <+> pprArg y -- unary [x] -> pprMachOp_for_C platform mop <> parens (pprArg x) _ -> panic "PprC.pprMachOp : machop with wrong number of args" where -- Cast needed for signed integer ops pprArg e | signedOp mop = cCast platform (machRep_S_CType platform (typeWidth (cmmExprType platform e))) e | needsFCasts mop = cCast platform (machRep_F_CType (typeWidth (cmmExprType platform e))) e | otherwise = pprExpr1 platform 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 :: Platform -> CmmLit -> SDoc pprLit platform lit = case lit of CmmInt i rep -> pprHexVal platform 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 -- 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 _ -- non-word widths not supported via C -- 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 '&' <> pprCLabel platform CStyle lbl pprLit1 :: Platform -> CmmLit -> SDoc pprLit1 platform lit = case lit of (CmmLabelOff _ _) -> parens (pprLit platform lit) (CmmLabelDiffOff _ _ _ _) -> parens (pprLit platform lit) (CmmFloat _ _) -> parens (pprLit platform lit) _ -> pprLit platform lit -- --------------------------------------------------------------------------- -- Static data -- | Produce a list of word sized literals encoding the given list of 'CmmLit's. staticLitsToWords :: Platform -> [CmmLit] -> [SDoc] staticLitsToWords platform = go . foldMap decomposeMultiWord where -- rem_bytes is how many bytes remain in the word we are currently filling. -- accum is the word we are filling. go :: [CmmLit] -> [SDoc] go [] = [] go lits@(lit : _) | Just _ <- isSubWordLit lit = goSubWord wordWidthBytes 0 lits go (lit : rest) = pprLit1 platform lit : go rest goSubWord :: Int -> Integer -> [CmmLit] -> [SDoc] goSubWord rem_bytes accum (lit : rest) | Just (bytes, w) <- isSubWordLit lit , rem_bytes >= widthInBytes w = let accum' = (accum `shiftL` widthInBits w) .|. fixEndian w bytes in goSubWord (rem_bytes - widthInBytes w) accum' rest goSubWord rem_bytes accum rest = pprWord (fixEndian (wordWidth platform) $ accum `shiftL` (8*rem_bytes)) : go rest fixEndian :: Width -> Integer -> Integer fixEndian w = case platformByteOrder platform of BigEndian -> id LittleEndian -> byteSwap w -- Decompose multi-word or floating-point literals into multiple -- single-word (or smaller) literals. decomposeMultiWord :: CmmLit -> [CmmLit] decomposeMultiWord (CmmFloat n W64) -- This will produce a W64 integer, which will then be broken up further -- on the next iteration on 32-bit platforms. = [doubleToWord64 n] decomposeMultiWord (CmmFloat n W32) = [floatToWord32 n] decomposeMultiWord (CmmInt n W64) | W32 <- wordWidth platform = [CmmInt hi W32, CmmInt lo W32] where hi = n `shiftR` 32 lo = n .&. 0xffffffff decomposeMultiWord lit = [lit] -- Decompose a sub-word-sized literal into the integer value and its -- (sub-word-sized) width. isSubWordLit :: CmmLit -> Maybe (Integer, Width) isSubWordLit lit = case lit of CmmInt n w | w < wordWidth platform -> Just (n, w) _ -> Nothing wordWidthBytes = widthInBytes $ wordWidth platform pprWord :: Integer -> SDoc pprWord n = pprHexVal platform n (wordWidth platform) byteSwap :: Width -> Integer -> Integer byteSwap width n = foldl' f 0 bytes where f acc m = (acc `shiftL` 8) .|. m bytes = [ byte i | i <- [0..widthInBytes width - 1] ] byte i = (n `shiftR` (i*8)) .&. 0xff pprStatic :: Platform -> CmmStatic -> SDoc pprStatic platform s = case s of CmmStaticLit lit -> nest 4 (pprLit platform 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')) CmmFileEmbed {} -> panic "Unexpected CmmFileEmbed literal" -- --------------------------------------------------------------------------- -- 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 :: Platform -> MachOp -> SDoc pprMachOp_for_C platform 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 platform to) MO_SS_Conv from to | from == to -> empty MO_SS_Conv _from to -> parens (machRep_S_CType platform to) MO_XX_Conv from to | from == to -> empty MO_XX_Conv _from to -> parens (machRep_U_CType platform 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 platform 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!") MO_AlignmentCheck {} -> panic "-falignment-santisation not supported by unregisterised backend" 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_Atanh -> text "atanh" MO_F64_Asinh -> text "asinh" MO_F64_Acosh -> text "acosh" MO_F64_Atan -> text "atan" MO_F64_Log -> text "log" MO_F64_Log1P -> text "log1p" MO_F64_Exp -> text "exp" MO_F64_ExpM1 -> text "expm1" 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_Asinh -> text "asinhf" MO_F32_Acosh -> text "acoshf" MO_F32_Atanh -> text "atanhf" MO_F32_Log -> text "logf" MO_F32_Log1P -> text "log1pf" MO_F32_Exp -> text "expf" MO_F32_ExpM1 -> text "expm1f" MO_F32_Sqrt -> text "sqrtf" MO_F32_Fabs -> text "fabsf" MO_ReadBarrier -> text "load_load_barrier" MO_WriteBarrier -> text "write_barrier" MO_Memcpy _ -> text "memcpy" MO_Memset _ -> text "memset" MO_Memmove _ -> text "memmove" MO_Memcmp _ -> text "memcmp" MO_BSwap w -> ftext (bSwapLabel w) MO_BRev w -> ftext (bRevLabel w) MO_PopCnt w -> ftext (popCntLabel w) MO_Pext w -> ftext (pextLabel w) MO_Pdep w -> ftext (pdepLabel w) MO_Clz w -> ftext (clzLabel w) MO_Ctz w -> ftext (ctzLabel w) MO_AtomicRMW w amop -> ftext (atomicRMWLabel w amop) MO_Cmpxchg w -> ftext (cmpxchgLabel w) MO_Xchg w -> ftext (xchgLabel w) MO_AtomicRead w -> ftext (atomicReadLabel w) MO_AtomicWrite w -> ftext (atomicWriteLabel w) MO_UF_Conv w -> ftext (word2FloatLabel w) MO_S_Mul2 {} -> unsupported MO_S_QuotRem {} -> unsupported MO_U_QuotRem {} -> unsupported MO_U_QuotRem2 {} -> unsupported MO_Add2 {} -> unsupported MO_AddWordC {} -> 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 :: Platform -> 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 platform r1 (CmmRegOff r2 off) | isPtrReg r1 && isPtrReg r2 && (off `rem` platformWordSizeInBytes platform == 0) = hcat [ pprAsPtrReg r1, equals, pprAsPtrReg r2, op, int off', semi ] where off1 = off `shiftR` wordShift platform (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 platform r1 r2 | isFixedPtrReg r1 = mkAssign (mkP_ <> pprExpr1 platform r2) | Just ty <- strangeRegType r1 = mkAssign (parens ty <> pprExpr1 platform r2) | otherwise = mkAssign (pprExpr platform 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 :: Platform -> SDoc -> CCallConv -> [Hinted CmmFormal] -> [Hinted CmmActual] -> SDoc pprCall platform 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 platform (text "void *") expr -- see comment by machRepHintCType below pprArg (expr, SignedHint) = cCast platform (machRep_S_CType platform $ typeWidth $ cmmExprType platform expr) expr pprArg (expr, _other) = pprExpr platform expr pprUnHint AddrHint rep = parens (machRepCType platform rep) pprUnHint SignedHint rep = parens (machRepCType platform 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 :: Platform -> [CmmBlock] -> (SDoc{-temps-}, SDoc{-externs-}) pprTempAndExternDecls platform stmts = (pprUFM (getUniqSet temps) (vcat . map (pprTempDecl platform)), vcat (map (pprExternDecl platform) (Map.keys lbls))) where (temps, lbls) = runTE (mapM_ te_BB stmts) pprDataExterns :: Platform -> [CmmStatic] -> SDoc pprDataExterns platform statics = vcat (map (pprExternDecl platform) (Map.keys lbls)) where (_, lbls) = runTE (mapM_ te_Static statics) pprTempDecl :: Platform -> LocalReg -> SDoc pprTempDecl platform l@(LocalReg _ rep) = hcat [ machRepCType platform rep, space, pprLocalReg l, semi ] pprExternDecl :: Platform -> CLabel -> SDoc pprExternDecl platform 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, pprCLabel platform CStyle lbl, text ");" -- occasionally useful to see label type -- , text "/* ", pprDebugCLabel lbl, text " */" ] where label_type lbl | isBytesLabel lbl = text "B_" | isForeignLabel lbl && isCFunctionLabel lbl = text "FF_" | isCFunctionLabel lbl = text "F_" | isStaticClosureLabel lbl = text "C_" -- generic .rodata labels | isSomeRODataLabel lbl = text "RO_" -- generic .data labels (common case) | otherwise = text "RW_" 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 = text "extern __attribute__((stdcall)) void " <> pprCLabel platform CStyle lbl <> parens (commafy (replicate (sz `quot` platformWordSizeInBytes platform) (machRep_U_CType platform (wordWidth platform)))) <> semi type TEState = (UniqSet LocalReg, Map CLabel ()) newtype TE a = TE { unTE :: TEState -> (a, TEState) } deriving (Functor) 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 :: Platform -> SDoc -> CmmExpr -> SDoc cCast platform ty expr = parens ty <> pprExpr1 platform expr cLoad :: Platform -> CmmExpr -> CmmType -> SDoc cLoad platform expr rep = if bewareLoadStoreAlignment (platformArch platform) then let decl = machRepCType platform rep <+> text "x" <> semi struct = text "struct" <+> braces (decl) packed_attr = text "__attribute__((packed))" cast = parens (struct <+> packed_attr <> char '*') in parens (cast <+> pprExpr1 platform expr) <> text "->x" else char '*' <> parens (cCast platform (machRepPtrCType platform 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 ArchAArch64 = True bewareLoadStoreAlignment ArchSPARC = True bewareLoadStoreAlignment ArchSPARC64 = True -- Pessimistically assume that they will also cause problems -- on unknown arches bewareLoadStoreAlignment ArchUnknown = True bewareLoadStoreAlignment _ = False isCmmWordType :: Platform -> CmmType -> Bool -- True of GcPtrReg/NonGcReg of native word size isCmmWordType platform ty = not (isFloatType ty) && typeWidth ty == wordWidth platform -- 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 :: Platform -> CmmType -> ForeignHint -> SDoc machRepHintCType platform rep = \case AddrHint -> text "void *" SignedHint -> machRep_S_CType platform (typeWidth rep) _other -> machRepCType platform rep machRepPtrCType :: Platform -> CmmType -> SDoc machRepPtrCType platform r = if isCmmWordType platform r then text "P_" else machRepCType platform r <> char '*' machRepCType :: Platform -> CmmType -> SDoc machRepCType platform ty | isFloatType ty = machRep_F_CType w | otherwise = machRep_U_CType platform 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 :: Platform -> Width -> SDoc machRep_U_CType platform w = case w of _ | w == wordWidth platform -> text "W_" W8 -> text "StgWord8" W16 -> text "StgWord16" W32 -> text "StgWord32" W64 -> text "StgWord64" _ -> panic "machRep_U_CType" machRep_S_CType :: Platform -> Width -> SDoc machRep_S_CType platform w = case w of _ | w == wordWidth platform -> 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 :: ByteString -> SDoc pprStringInCStyle s = doubleQuotes (text (concatMap charToC (BS.unpack 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. floatToWord32 :: Rational -> CmmLit floatToWord32 r = runST $ do arr <- newArray_ ((0::Int),0) writeArray arr 0 (fromRational r) arr' <- castFloatToWord32Array arr w32 <- readArray arr' 0 return (CmmInt (toInteger w32) W32) where castFloatToWord32Array :: STUArray s Int Float -> ST s (STUArray s Int Word32) castFloatToWord32Array = U.castSTUArray doubleToWord64 :: Rational -> CmmLit doubleToWord64 r = runST $ do arr <- newArray_ ((0::Int),1) writeArray arr 0 (fromRational r) arr' <- castDoubleToWord64Array arr w64 <- readArray arr' 0 return $ CmmInt (toInteger w64) W64 where castDoubleToWord64Array :: STUArray s Int Double -> ST s (STUArray s Int Word64) castDoubleToWord64Array = U.castSTUArray -- --------------------------------------------------------------------------- -- Utils wordShift :: Platform -> Int wordShift platform = widthInLog (wordWidth platform) commafy :: [SDoc] -> SDoc commafy xs = hsep $ punctuate comma xs -- | Print in C hex format -- -- Examples: -- -- 5114 :: W32 ===> ((StgWord32)0x13faU) -- (-5114) :: W32 ===> ((StgWord32)(-0x13faU)) -- -- We use casts to support types smaller than `unsigned int`; C literal -- suffixes support longer but not shorter types. pprHexVal :: Platform -> Integer -> Width -> SDoc pprHexVal platform w rep = parens ctype <> rawlit where rawlit | w < 0 = parens (char '-' <> text "0x" <> intToDoc (-w) <> repsuffix rep) | otherwise = text "0x" <> intToDoc w <> repsuffix rep ctype = machRep_U_CType platform rep -- 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. constants = platformConstants platform repsuffix W64 = if pc_CINT_SIZE constants == 8 then char 'U' else if pc_CLONG_SIZE constants == 8 then text "UL" else if pc_CLONG_LONG_SIZE constants == 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'))