1 ----------------------------------------------------------------------------
3 -- Pretty-printing of Cmm as (a superset of) C--
5 -- (c) The University of Glasgow 2004-2006
7 -----------------------------------------------------------------------------
10 -- This is where we walk over Cmm emitting an external representation,
11 -- suitable for parsing, in a syntax strongly reminiscent of C--. This
12 -- is the "External Core" for the Cmm layer.
14 -- As such, this should be a well-defined syntax: we want it to look nice.
15 -- Thus, we try wherever possible to use syntax defined in [1],
16 -- "The C-- Reference Manual", http://www.cminusminus.org/. We differ
17 -- slightly, in some cases. For one, we use I8 .. I64 for types, rather
18 -- than C--'s bits8 .. bits64.
20 -- We try to ensure that all information available in the abstract
21 -- syntax is reproduced, or reproducible, in the concrete syntax.
22 -- Data that is not in printed out can be reconstructed according to
23 -- conventions used in the pretty printer. There are at least two such
25 -- 1) if a value has wordRep type, the type is not appended in the
27 -- 2) MachOps that operate over wordRep type are printed in a
28 -- C-style, rather than as their internal MachRep name.
30 -- These conventions produce much more readable Cmm output.
32 -- A useful example pass over Cmm is in nativeGen/MachCodeGen.hs
36 ( writeCmms, pprCmms, pprCmm, pprStmt, pprExpr,
37 pprSection, pprStatic, pprLit
59 #include "../includes/StgFun.h"
62 pprCmms :: (Outputable info, Outputable g) => [GenCmm CmmStatic info g] -> SDoc
63 pprCmms cmms = pprCode CStyle (vcat (intersperse separator $ map ppr cmms))
65 separator = space $$ ptext (sLit "-------------------") $$ space
67 writeCmms :: Handle -> [Cmm] -> IO ()
68 writeCmms handle cmms = printForC handle (pprCmms cmms)
70 -----------------------------------------------------------------------------
72 instance (Outputable d, Outputable info, Outputable g)
73 => Outputable (GenCmm d info g) where
76 instance (Outputable d, Outputable info, Outputable i)
77 => Outputable (GenCmmTop d info i) where
80 instance (Outputable instr) => Outputable (ListGraph instr) where
81 ppr (ListGraph blocks) = vcat (map ppr blocks)
83 instance (Outputable instr) => Outputable (GenBasicBlock instr) where
86 instance Outputable CmmStmt where
89 instance Outputable CmmExpr where
92 instance Outputable CmmReg where
95 instance Outputable CmmLit where
98 instance Outputable LocalReg where
101 instance Outputable Area where
104 instance Outputable GlobalReg where
105 ppr e = pprGlobalReg e
107 instance Outputable CmmStatic where
110 instance Outputable CmmInfo where
115 -----------------------------------------------------------------------------
117 pprCmm :: (Outputable d, Outputable info, Outputable g) => GenCmm d info g -> SDoc
118 pprCmm (Cmm tops) = vcat $ intersperse (text "") $ map pprTop tops
120 -- --------------------------------------------------------------------------
121 -- Top level `procedure' blocks.
123 pprTop :: (Outputable d, Outputable info, Outputable i)
124 => GenCmmTop d info i -> SDoc
126 pprTop (CmmProc info lbl params graph )
128 = vcat [ pprCLabel lbl <> parens (commafy $ map ppr params)
129 , nest 8 $ lbrace <+> ppr info $$ rbrace
133 -- --------------------------------------------------------------------------
134 -- We follow [1], 4.5
136 -- section "data" { ... }
138 pprTop (CmmData section ds) =
139 (hang (pprSection section <+> lbrace) 4 (vcat (map ppr ds)))
142 -- --------------------------------------------------------------------------
143 instance Outputable CmmSafety where
144 ppr CmmUnsafe = ptext (sLit "_unsafe_call_")
145 ppr (CmmSafe srt) = ppr srt
147 -- --------------------------------------------------------------------------
148 -- Info tables. The current pretty printer needs refinement
149 -- but will work for now.
151 -- For ideas on how to refine it, they used to be printed in the
152 -- style of C--'s 'stackdata' declaration, just inside the proc body,
153 -- and were labelled with the procedure name ++ "_info".
154 pprInfo :: CmmInfo -> SDoc
155 pprInfo (CmmInfo _gc_target update_frame CmmNonInfoTable) =
156 vcat [{-ptext (sLit "gc_target: ") <>
157 maybe (ptext (sLit "<none>")) ppr gc_target,-}
158 ptext (sLit "update_frame: ") <>
159 maybe (ptext (sLit "<none>")) pprUpdateFrame update_frame]
160 pprInfo (CmmInfo _gc_target update_frame
161 (CmmInfoTable stat_clos (ProfilingInfo closure_type closure_desc) tag info)) =
162 vcat [{-ptext (sLit "gc_target: ") <>
163 maybe (ptext (sLit "<none>")) ppr gc_target,-}
164 ptext (sLit "has static closure: ") <> ppr stat_clos <+>
165 ptext (sLit "update_frame: ") <>
166 maybe (ptext (sLit "<none>")) pprUpdateFrame update_frame,
167 ptext (sLit "type: ") <> pprLit closure_type,
168 ptext (sLit "desc: ") <> pprLit closure_desc,
169 ptext (sLit "tag: ") <> integer (toInteger tag),
172 pprTypeInfo :: ClosureTypeInfo -> SDoc
173 pprTypeInfo (ConstrInfo layout constr descr) =
174 vcat [ptext (sLit "ptrs: ") <> integer (toInteger (fst layout)),
175 ptext (sLit "nptrs: ") <> integer (toInteger (snd layout)),
176 ptext (sLit "constructor: ") <> integer (toInteger constr),
178 pprTypeInfo (FunInfo layout srt arity _args slow_entry) =
179 vcat [ptext (sLit "ptrs: ") <> integer (toInteger (fst layout)),
180 ptext (sLit "nptrs: ") <> integer (toInteger (snd layout)),
181 ptext (sLit "srt: ") <> ppr srt,
183 ptext (sLit ("fun_type: ")) <> integer (toInteger (argDescrType _args)),
185 ptext (sLit "arity: ") <> integer (toInteger arity),
186 --ptext (sLit "args: ") <> ppr args, -- TODO: needs to be printed
187 ptext (sLit "slow: ") <> pprLit slow_entry
189 pprTypeInfo (ThunkInfo layout srt) =
190 vcat [ptext (sLit "ptrs: ") <> integer (toInteger (fst layout)),
191 ptext (sLit "nptrs: ") <> integer (toInteger (snd layout)),
192 ptext (sLit "srt: ") <> ppr srt]
193 pprTypeInfo (ThunkSelectorInfo offset srt) =
194 vcat [ptext (sLit "ptrs: ") <> integer (toInteger offset),
195 ptext (sLit "srt: ") <> ppr srt]
196 pprTypeInfo (ContInfo stack srt) =
197 vcat [ptext (sLit "stack: ") <> ppr stack,
198 ptext (sLit "srt: ") <> ppr srt]
201 argDescrType :: ArgDescr -> StgHalfWord
202 -- The "argument type" RTS field type
203 argDescrType (ArgSpec n) = n
204 argDescrType (ArgGen liveness)
205 | isBigLiveness liveness = ARG_GEN_BIG
206 | otherwise = ARG_GEN
209 isBigLiveness :: Liveness -> Bool
210 isBigLiveness (BigLiveness _) = True
211 isBigLiveness (SmallLiveness _) = False
214 pprUpdateFrame :: UpdateFrame -> SDoc
215 pprUpdateFrame (UpdateFrame expr args) =
216 hcat [ ptext (sLit "jump")
218 , if isTrivialCmmExpr expr
221 CmmLoad (CmmReg _) _ -> pprExpr expr
222 _ -> parens (pprExpr expr)
224 , parens ( commafy $ map ppr args ) ]
227 -- --------------------------------------------------------------------------
228 -- Basic blocks look like assembly blocks.
229 -- lbl: stmt ; stmt ; ..
230 pprBBlock :: Outputable stmt => GenBasicBlock stmt -> SDoc
231 pprBBlock (BasicBlock ident stmts) =
232 hang (ppr ident <> colon) 4 (vcat (map ppr stmts))
234 -- --------------------------------------------------------------------------
235 -- Statements. C-- usually, exceptions to this should be obvious.
237 pprStmt :: CmmStmt -> SDoc
238 pprStmt stmt = case stmt of
244 CmmComment s -> text "//" <+> ftext s
247 CmmAssign reg expr -> ppr reg <+> equals <+> ppr expr <> semi
250 CmmStore lv expr -> rep <> brackets(ppr lv) <+> equals <+> ppr expr <> semi
252 rep = ppr ( cmmExprType expr )
254 -- call "ccall" foo(x, y)[r1, r2];
256 CmmCall (CmmCallee fn cconv) results args safety ret ->
257 sep [ pp_lhs <+> pp_conv
258 , nest 2 (pprExpr9 fn <>
259 parens (commafy (map ppr_ar args)))
260 <> brackets (ppr safety)
261 , case ret of CmmMayReturn -> empty
262 CmmNeverReturns -> ptext $ sLit (" never returns")
265 pp_lhs | null results = empty
266 | otherwise = commafy (map ppr_ar results) <+> equals
267 -- Don't print the hints on a native C-- call
268 ppr_ar (CmmHinted ar k) = case cconv of
269 CmmCallConv -> ppr ar
271 pp_conv = case cconv of
273 _ -> ptext (sLit("foreign")) <+> doubleQuotes (ppr cconv)
275 CmmCall (CmmPrim op) results args safety ret ->
276 pprStmt (CmmCall (CmmCallee (CmmLit lbl) CCallConv)
277 results args safety ret)
279 lbl = CmmLabel (mkForeignLabel (mkFastString (show op)) Nothing False IsFunction)
281 CmmBranch ident -> genBranch ident
282 CmmCondBranch expr ident -> genCondBranch expr ident
283 CmmJump expr params -> genJump expr params
284 CmmReturn params -> genReturn params
285 CmmSwitch arg ids -> genSwitch arg ids
287 instance Outputable ForeignHint where
289 ppr SignedHint = quotes(text "signed")
290 -- ppr AddrHint = quotes(text "address")
292 ppr AddrHint = (text "PtrHint")
294 -- Just look like a tuple, since it was a tuple before
295 -- ... is that a good idea? --Isaac Dupree
296 instance (Outputable a) => Outputable (CmmHinted a) where
297 ppr (CmmHinted a k) = ppr (a, k)
299 -- --------------------------------------------------------------------------
300 -- goto local label. [1], section 6.6
304 genBranch :: BlockId -> SDoc
306 ptext (sLit "goto") <+> ppr ident <> semi
308 -- --------------------------------------------------------------------------
309 -- Conditional. [1], section 6.4
311 -- if (expr) { goto lbl; }
313 genCondBranch :: CmmExpr -> BlockId -> SDoc
314 genCondBranch expr ident =
315 hsep [ ptext (sLit "if")
317 , ptext (sLit "goto")
318 , ppr ident <> semi ]
320 -- --------------------------------------------------------------------------
321 -- A tail call. [1], Section 6.9
323 -- jump foo(a, b, c);
325 genJump :: CmmExpr -> [CmmHinted CmmExpr] -> SDoc
327 hcat [ ptext (sLit "jump")
329 , if isTrivialCmmExpr expr
332 CmmLoad (CmmReg _) _ -> pprExpr expr
333 _ -> parens (pprExpr expr)
335 , parens ( commafy $ map ppr args )
339 -- --------------------------------------------------------------------------
340 -- Return from a function. [1], Section 6.8.2 of version 1.128
344 genReturn :: [CmmHinted CmmExpr] -> SDoc
346 hcat [ ptext (sLit "return")
348 , parens ( commafy $ map ppr args )
351 -- --------------------------------------------------------------------------
352 -- Tabled jump to local label
354 -- The syntax is from [1], section 6.5
356 -- switch [0 .. n] (expr) { case ... ; }
358 genSwitch :: CmmExpr -> [Maybe BlockId] -> SDoc
359 genSwitch expr maybe_ids
361 = let pairs = groupBy snds (zip [0 .. ] maybe_ids )
363 in hang (hcat [ ptext (sLit "switch [0 .. ")
364 , int (length maybe_ids - 1)
366 , if isTrivialCmmExpr expr
368 else parens (pprExpr expr)
371 4 (vcat ( map caseify pairs )) $$ rbrace
374 snds a b = (snd a) == (snd b)
376 caseify :: [(Int,Maybe BlockId)] -> SDoc
377 caseify ixs@((_,Nothing):_)
378 = ptext (sLit "/* impossible: ") <> hcat (intersperse comma (map (int.fst) ixs))
379 <> ptext (sLit " */")
381 = let (is,ids) = unzip as
382 in hsep [ ptext (sLit "case")
383 , hcat (punctuate comma (map int is))
384 , ptext (sLit ": goto")
385 , ppr (head [ id | Just id <- ids]) <> semi ]
387 -- --------------------------------------------------------------------------
391 pprExpr :: CmmExpr -> SDoc
395 pprExpr (CmmMachOp (MO_Add rep)
396 [CmmReg reg, CmmLit (CmmInt (fromIntegral i) rep)])
397 where rep = typeWidth (cmmRegType reg)
398 CmmLit lit -> pprLit lit
401 -- Here's the precedence table from CmmParse.y:
402 -- %nonassoc '>=' '>' '<=' '<' '!=' '=='
411 -- We just cope with the common operators for now, the rest will get
412 -- a default conservative behaviour.
414 -- %nonassoc '>=' '>' '<=' '<' '!=' '=='
415 pprExpr1, pprExpr7, pprExpr8 :: CmmExpr -> SDoc
416 pprExpr1 (CmmMachOp op [x,y]) | Just doc <- infixMachOp1 op
417 = pprExpr7 x <+> doc <+> pprExpr7 y
418 pprExpr1 e = pprExpr7 e
420 infixMachOp1, infixMachOp7, infixMachOp8 :: MachOp -> Maybe SDoc
422 infixMachOp1 (MO_Eq _) = Just (ptext (sLit "=="))
423 infixMachOp1 (MO_Ne _) = Just (ptext (sLit "!="))
424 infixMachOp1 (MO_Shl _) = Just (ptext (sLit "<<"))
425 infixMachOp1 (MO_U_Shr _) = Just (ptext (sLit ">>"))
426 infixMachOp1 (MO_U_Ge _) = Just (ptext (sLit ">="))
427 infixMachOp1 (MO_U_Le _) = Just (ptext (sLit "<="))
428 infixMachOp1 (MO_U_Gt _) = Just (char '>')
429 infixMachOp1 (MO_U_Lt _) = Just (char '<')
430 infixMachOp1 _ = Nothing
433 pprExpr7 (CmmMachOp (MO_Add rep1) [x, CmmLit (CmmInt i rep2)]) | i < 0
434 = pprExpr7 (CmmMachOp (MO_Sub rep1) [x, CmmLit (CmmInt (negate i) rep2)])
435 pprExpr7 (CmmMachOp op [x,y]) | Just doc <- infixMachOp7 op
436 = pprExpr7 x <+> doc <+> pprExpr8 y
437 pprExpr7 e = pprExpr8 e
439 infixMachOp7 (MO_Add _) = Just (char '+')
440 infixMachOp7 (MO_Sub _) = Just (char '-')
441 infixMachOp7 _ = Nothing
444 pprExpr8 (CmmMachOp op [x,y]) | Just doc <- infixMachOp8 op
445 = pprExpr8 x <+> doc <+> pprExpr9 y
446 pprExpr8 e = pprExpr9 e
448 infixMachOp8 (MO_U_Quot _) = Just (char '/')
449 infixMachOp8 (MO_Mul _) = Just (char '*')
450 infixMachOp8 (MO_U_Rem _) = Just (char '%')
451 infixMachOp8 _ = Nothing
453 pprExpr9 :: CmmExpr -> SDoc
456 CmmLit lit -> pprLit1 lit
457 CmmLoad expr rep -> ppr rep <> brackets( ppr expr )
458 CmmReg reg -> ppr reg
459 CmmRegOff reg off -> parens (ppr reg <+> char '+' <+> int off)
460 CmmStackSlot a off -> parens (ppr a <+> char '+' <+> int off)
461 CmmMachOp mop args -> genMachOp mop args
463 genMachOp :: MachOp -> [CmmExpr] -> SDoc
465 | Just doc <- infixMachOp mop = case args of
467 [x,y] -> pprExpr9 x <+> doc <+> pprExpr9 y
470 [x] -> doc <> pprExpr9 x
472 _ -> pprTrace "PprCmm.genMachOp: machop with strange number of args"
474 parens (hcat $ punctuate comma (map pprExpr args)))
477 | isJust (infixMachOp1 mop)
478 || isJust (infixMachOp7 mop)
479 || isJust (infixMachOp8 mop) = parens (pprExpr (CmmMachOp mop args))
481 | otherwise = char '%' <> ppr_op <> parens (commafy (map pprExpr args))
482 where ppr_op = text (map (\c -> if c == ' ' then '_' else c)
484 -- replace spaces in (show mop) with underscores,
487 -- Unsigned ops on the word size of the machine get nice symbols.
488 -- All else get dumped in their ugly format.
490 infixMachOp :: MachOp -> Maybe SDoc
493 MO_And _ -> Just $ char '&'
494 MO_Or _ -> Just $ char '|'
495 MO_Xor _ -> Just $ char '^'
496 MO_Not _ -> Just $ char '~'
497 MO_S_Neg _ -> Just $ char '-' -- there is no unsigned neg :)
500 -- --------------------------------------------------------------------------
502 -- To minimise line noise we adopt the convention that if the literal
503 -- has the natural machine word size, we do not append the type
505 pprLit :: CmmLit -> SDoc
506 pprLit lit = case lit of
508 hcat [ (if i < 0 then parens else id)(integer i)
509 , (if rep == wordWidth
511 else space <> dcolon <+> ppr rep) ]
513 CmmFloat f rep -> hsep [ rational f, dcolon, ppr rep ]
514 CmmLabel clbl -> pprCLabel clbl
515 CmmLabelOff clbl i -> pprCLabel clbl <> ppr_offset i
516 CmmLabelDiffOff clbl1 clbl2 i -> pprCLabel clbl1 <> char '-'
517 <> pprCLabel clbl2 <> ppr_offset i
518 CmmBlock id -> ppr id
519 CmmHighStackMark -> text "<highSp>"
521 pprLit1 :: CmmLit -> SDoc
522 pprLit1 lit@(CmmLabelOff {}) = parens (pprLit lit)
523 pprLit1 lit = pprLit lit
525 ppr_offset :: Int -> SDoc
528 | i>=0 = char '+' <> int i
529 | otherwise = char '-' <> int (-i)
531 -- --------------------------------------------------------------------------
533 -- Strings are printed as C strings, and we print them as I8[],
536 pprStatic :: CmmStatic -> SDoc
537 pprStatic s = case s of
538 CmmStaticLit lit -> nest 4 $ ptext (sLit "const") <+> pprLit lit <> semi
539 CmmUninitialised i -> nest 4 $ text "I8" <> brackets (int i)
540 CmmAlign i -> nest 4 $ text "align" <+> int i
541 CmmDataLabel clbl -> pprCLabel clbl <> colon
542 CmmString s' -> nest 4 $ text "I8[]" <+> text (show s')
544 -- --------------------------------------------------------------------------
545 -- Registers, whether local (temps) or global
547 pprReg :: CmmReg -> SDoc
550 CmmLocal local -> pprLocalReg local
551 CmmGlobal global -> pprGlobalReg global
554 -- We only print the type of the local reg if it isn't wordRep
556 pprLocalReg :: LocalReg -> SDoc
557 pprLocalReg (LocalReg uniq rep)
558 -- = ppr rep <> char '_' <> ppr uniq
560 = char '_' <> ppr uniq <>
561 (if isWord32 rep -- && not (isGcPtrType rep) -- Temp Jan08 -- sigh
562 then dcolon <> ptr <> ppr rep
563 else dcolon <> ptr <> ppr rep)
567 -- then doubleQuotes (text "ptr")
571 pprArea :: Area -> SDoc
572 pprArea (RegSlot r) = hcat [ text "slot<", ppr r, text ">" ]
573 pprArea (CallArea id) = pprAreaId id
575 pprAreaId :: AreaId -> SDoc
576 pprAreaId Old = text "old"
577 pprAreaId (Young id) = hcat [ text "young<", ppr id, text ">" ]
579 -- needs to be kept in syn with Cmm.hs.GlobalReg
581 pprGlobalReg :: GlobalReg -> SDoc
584 VanillaReg n _ -> char 'R' <> int n
586 -- VanillaReg n VNonGcPtr -> char 'R' <> int n
587 -- VanillaReg n VGcPtr -> char 'P' <> int n
588 FloatReg n -> char 'F' <> int n
589 DoubleReg n -> char 'D' <> int n
590 LongReg n -> char 'L' <> int n
591 Sp -> ptext (sLit "Sp")
592 SpLim -> ptext (sLit "SpLim")
593 Hp -> ptext (sLit "Hp")
594 HpLim -> ptext (sLit "HpLim")
595 CurrentTSO -> ptext (sLit "CurrentTSO")
596 CurrentNursery -> ptext (sLit "CurrentNursery")
597 HpAlloc -> ptext (sLit "HpAlloc")
598 EagerBlackholeInfo -> ptext (sLit "stg_EAGER_BLACKHOLE_info")
599 GCEnter1 -> ptext (sLit "stg_gc_enter_1")
600 GCFun -> ptext (sLit "stg_gc_fun")
601 BaseReg -> ptext (sLit "BaseReg")
602 PicBaseReg -> ptext (sLit "PicBaseReg")
604 -- --------------------------------------------------------------------------
607 pprSection :: Section -> SDoc
608 pprSection s = case s of
609 Text -> section <+> doubleQuotes (ptext (sLit "text"))
610 Data -> section <+> doubleQuotes (ptext (sLit "data"))
611 ReadOnlyData -> section <+> doubleQuotes (ptext (sLit "readonly"))
612 ReadOnlyData16 -> section <+> doubleQuotes (ptext (sLit "readonly16"))
613 RelocatableReadOnlyData
614 -> section <+> doubleQuotes (ptext (sLit "relreadonly"))
615 UninitialisedData -> section <+> doubleQuotes (ptext (sLit "uninitialised"))
616 OtherSection s' -> section <+> doubleQuotes (text s')
618 section = ptext (sLit "section")
620 -----------------------------------------------------------------------------
622 commafy :: [SDoc] -> SDoc
623 commafy xs = fsep $ punctuate comma xs