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
39 #include "HsVersions.h"
55 pprCmms :: (Outputable info) => [GenCmm CmmStatic info CmmStmt] -> SDoc
56 pprCmms cmms = pprCode CStyle (vcat (intersperse separator $ map ppr cmms))
58 separator = space $$ ptext SLIT("-------------------") $$ space
60 writeCmms :: Handle -> [Cmm] -> IO ()
61 writeCmms handle cmms = printForC handle (pprCmms cmms)
63 -----------------------------------------------------------------------------
65 instance (Outputable info) => Outputable (GenCmm CmmStatic info CmmStmt) where
68 instance (Outputable info) => Outputable (GenCmmTop CmmStatic info CmmStmt) where
71 instance Outputable CmmBasicBlock where
74 instance Outputable CmmStmt where
77 instance Outputable CmmExpr where
80 instance Outputable CmmReg where
83 instance Outputable LocalReg where
86 instance Outputable GlobalReg where
87 ppr e = pprGlobalReg e
89 instance Outputable CmmStatic where
92 instance Outputable CmmInfo where
95 -----------------------------------------------------------------------------
97 pprCmm :: (Outputable info) => GenCmm CmmStatic info CmmStmt -> SDoc
98 pprCmm (Cmm tops) = vcat $ intersperse (text "") $ map pprTop tops
100 -- --------------------------------------------------------------------------
101 -- Top level `procedure' blocks.
103 pprTop :: (Outputable info) => GenCmmTop CmmStatic info CmmStmt -> SDoc
104 pprTop (CmmProc info lbl params blocks )
106 = vcat [ pprCLabel lbl <> parens (commafy $ map ppr params) <+> lbrace
107 , nest 8 $ lbrace <+> ppr info $$ rbrace
108 , nest 4 $ vcat (map ppr blocks)
111 -- --------------------------------------------------------------------------
112 -- We follow [1], 4.5
114 -- section "data" { ... }
116 pprTop (CmmData section ds) =
117 (hang (pprSection section <+> lbrace) 4 (vcat (map pprStatic ds)))
120 -- --------------------------------------------------------------------------
121 instance Outputable CmmSafety where
122 ppr CmmUnsafe = ptext SLIT("_unsafe_call_")
123 ppr (CmmSafe srt) = ppr srt
125 -- --------------------------------------------------------------------------
126 -- Info tables. The current pretty printer needs refinement
127 -- but will work for now.
129 -- For ideas on how to refine it, they used to be printed in the
130 -- style of C--'s 'stackdata' declaration, just inside the proc body,
131 -- and were labelled with the procedure name ++ "_info".
132 pprInfo (CmmInfo gc_target update_frame CmmNonInfoTable) =
133 vcat [ptext SLIT("gc_target: ") <>
134 maybe (ptext SLIT("<none>")) pprBlockId gc_target,
135 ptext SLIT("update_frame: ") <>
136 maybe (ptext SLIT("<none>")) pprUpdateFrame update_frame]
137 pprInfo (CmmInfo gc_target update_frame
138 (CmmInfoTable (ProfilingInfo closure_type closure_desc) tag info)) =
139 vcat [ptext SLIT("gc_target: ") <>
140 maybe (ptext SLIT("<none>")) pprBlockId gc_target,
141 ptext SLIT("update_frame: ") <>
142 maybe (ptext SLIT("<none>")) pprUpdateFrame update_frame,
143 ptext SLIT("type: ") <> pprLit closure_type,
144 ptext SLIT("desc: ") <> pprLit closure_desc,
145 ptext SLIT("tag: ") <> integer (toInteger tag),
148 pprTypeInfo (ConstrInfo layout constr descr) =
149 vcat [ptext SLIT("ptrs: ") <> integer (toInteger (fst layout)),
150 ptext SLIT("nptrs: ") <> integer (toInteger (snd layout)),
151 ptext SLIT("constructor: ") <> integer (toInteger constr),
153 pprTypeInfo (FunInfo layout srt fun_type arity args slow_entry) =
154 vcat [ptext SLIT("ptrs: ") <> integer (toInteger (fst layout)),
155 ptext SLIT("nptrs: ") <> integer (toInteger (snd layout)),
156 ptext SLIT("srt: ") <> ppr srt,
157 ptext SLIT("fun_type: ") <> integer (toInteger fun_type),
158 ptext SLIT("arity: ") <> integer (toInteger arity),
159 --ptext SLIT("args: ") <> ppr args, -- TODO: needs to be printed
160 ptext SLIT("slow: ") <> pprLit slow_entry
162 pprTypeInfo (ThunkInfo layout srt) =
163 vcat [ptext SLIT("ptrs: ") <> integer (toInteger (fst layout)),
164 ptext SLIT("nptrs: ") <> integer (toInteger (snd layout)),
165 ptext SLIT("srt: ") <> ppr srt]
166 pprTypeInfo (ThunkSelectorInfo offset srt) =
167 vcat [ptext SLIT("ptrs: ") <> integer (toInteger offset),
168 ptext SLIT("srt: ") <> ppr srt]
169 pprTypeInfo (ContInfo stack srt) =
170 vcat [ptext SLIT("stack: ") <> ppr stack,
171 ptext SLIT("srt: ") <> ppr srt]
173 pprUpdateFrame :: UpdateFrame -> SDoc
174 pprUpdateFrame (UpdateFrame expr args) =
175 hcat [ ptext SLIT("jump")
177 , if isTrivialCmmExpr expr
180 CmmLoad (CmmReg _) _ -> pprExpr expr
181 _ -> parens (pprExpr expr)
183 , parens ( commafy $ map ppr args ) ]
186 -- --------------------------------------------------------------------------
187 -- Basic blocks look like assembly blocks.
188 -- lbl: stmt ; stmt ; ..
189 pprBBlock :: CmmBasicBlock -> SDoc
190 pprBBlock (BasicBlock ident stmts) =
191 hang (pprBlockId ident <> colon) 4 (vcat (map ppr stmts))
193 -- --------------------------------------------------------------------------
194 -- Statements. C-- usually, exceptions to this should be obvious.
196 pprStmt :: CmmStmt -> SDoc
197 pprStmt stmt = case stmt of
203 CmmComment s -> text "//" <+> ftext s
206 CmmAssign reg expr -> ppr reg <+> equals <+> ppr expr <> semi
209 CmmStore lv expr -> rep <> brackets(ppr lv) <+> equals <+> ppr expr <> semi
211 rep = ppr ( cmmExprRep expr )
213 -- call "ccall" foo(x, y)[r1, r2];
215 CmmCall (CmmForeignCall fn cconv) results args safety ->
216 hcat [ if null results
218 else parens (commafy $ map ppr results) <>
220 ptext SLIT("call"), space,
221 doubleQuotes(ppr cconv), space,
222 target fn, parens ( commafy $ map ppr args ),
223 brackets (ppr safety), semi ]
225 target (CmmLit lit) = pprLit lit
226 target fn' = parens (ppr fn')
228 CmmCall (CmmPrim op) results args safety ->
229 pprStmt (CmmCall (CmmForeignCall (CmmLit lbl) CCallConv)
232 lbl = CmmLabel (mkForeignLabel (mkFastString (show op)) Nothing False)
234 CmmBranch ident -> genBranch ident
235 CmmCondBranch expr ident -> genCondBranch expr ident
236 CmmJump expr params -> genJump expr params
237 CmmReturn params -> genReturn params
238 CmmSwitch arg ids -> genSwitch arg ids
240 -- --------------------------------------------------------------------------
241 -- goto local label. [1], section 6.6
245 genBranch :: BlockId -> SDoc
247 ptext SLIT("goto") <+> pprBlockId ident <> semi
249 -- --------------------------------------------------------------------------
250 -- Conditional. [1], section 6.4
252 -- if (expr) { goto lbl; }
254 genCondBranch :: CmmExpr -> BlockId -> SDoc
255 genCondBranch expr ident =
256 hsep [ ptext SLIT("if")
259 , pprBlockId ident <> semi ]
261 -- --------------------------------------------------------------------------
262 -- A tail call. [1], Section 6.9
264 -- jump foo(a, b, c);
266 genJump :: CmmExpr -> [(CmmExpr, MachHint)] -> SDoc
269 hcat [ ptext SLIT("jump")
271 , if isTrivialCmmExpr expr
274 CmmLoad (CmmReg _) _ -> pprExpr expr
275 _ -> parens (pprExpr expr)
277 , parens ( commafy $ map ppr args )
280 -- --------------------------------------------------------------------------
281 -- Return from a function. [1], Section 6.8.2 of version 1.128
285 genReturn :: [(CmmExpr, MachHint)] -> SDoc
288 hcat [ ptext SLIT("return")
290 , parens ( commafy $ map ppr args )
293 -- --------------------------------------------------------------------------
294 -- Tabled jump to local label
296 -- The syntax is from [1], section 6.5
298 -- switch [0 .. n] (expr) { case ... ; }
300 genSwitch :: CmmExpr -> [Maybe BlockId] -> SDoc
301 genSwitch expr maybe_ids
303 = let pairs = groupBy snds (zip [0 .. ] maybe_ids )
305 in hang (hcat [ ptext SLIT("switch [0 .. ")
306 , int (length maybe_ids - 1)
308 , if isTrivialCmmExpr expr
310 else parens (pprExpr expr)
313 4 (vcat ( map caseify pairs )) $$ rbrace
316 snds a b = (snd a) == (snd b)
318 caseify :: [(Int,Maybe BlockId)] -> SDoc
319 caseify ixs@((i,Nothing):_)
320 = ptext SLIT("/* impossible: ") <> hcat (intersperse comma (map (int.fst) ixs))
323 = let (is,ids) = unzip as
324 in hsep [ ptext SLIT("case")
325 , hcat (punctuate comma (map int is))
326 , ptext SLIT(": goto")
327 , pprBlockId (head [ id | Just id <- ids]) <> semi ]
329 -- --------------------------------------------------------------------------
333 pprExpr :: CmmExpr -> SDoc
337 pprExpr (CmmMachOp (MO_Add rep)
338 [CmmReg reg, CmmLit (CmmInt (fromIntegral i) rep)])
339 where rep = cmmRegRep reg
340 CmmLit lit -> pprLit lit
343 -- Here's the precedence table from CmmParse.y:
344 -- %nonassoc '>=' '>' '<=' '<' '!=' '=='
353 -- We just cope with the common operators for now, the rest will get
354 -- a default conservative behaviour.
356 -- %nonassoc '>=' '>' '<=' '<' '!=' '=='
357 pprExpr1 (CmmMachOp op [x,y]) | Just doc <- infixMachOp1 op
358 = pprExpr7 x <+> doc <+> pprExpr7 y
359 pprExpr1 e = pprExpr7 e
361 infixMachOp1 (MO_Eq _) = Just (ptext SLIT("=="))
362 infixMachOp1 (MO_Ne _) = Just (ptext SLIT("!="))
363 infixMachOp1 (MO_Shl _) = Just (ptext SLIT("<<"))
364 infixMachOp1 (MO_U_Shr _) = Just (ptext SLIT(">>"))
365 infixMachOp1 (MO_U_Ge _) = Just (ptext SLIT(">="))
366 infixMachOp1 (MO_U_Le _) = Just (ptext SLIT("<="))
367 infixMachOp1 (MO_U_Gt _) = Just (char '>')
368 infixMachOp1 (MO_U_Lt _) = Just (char '<')
369 infixMachOp1 _ = Nothing
372 pprExpr7 (CmmMachOp (MO_Add rep1) [x, CmmLit (CmmInt i rep2)]) | i < 0
373 = pprExpr7 (CmmMachOp (MO_Sub rep1) [x, CmmLit (CmmInt (negate i) rep2)])
374 pprExpr7 (CmmMachOp op [x,y]) | Just doc <- infixMachOp7 op
375 = pprExpr7 x <+> doc <+> pprExpr8 y
376 pprExpr7 e = pprExpr8 e
378 infixMachOp7 (MO_Add _) = Just (char '+')
379 infixMachOp7 (MO_Sub _) = Just (char '-')
380 infixMachOp7 _ = Nothing
383 pprExpr8 (CmmMachOp op [x,y]) | Just doc <- infixMachOp8 op
384 = pprExpr8 x <+> doc <+> pprExpr9 y
385 pprExpr8 e = pprExpr9 e
387 infixMachOp8 (MO_U_Quot _) = Just (char '/')
388 infixMachOp8 (MO_Mul _) = Just (char '*')
389 infixMachOp8 (MO_U_Rem _) = Just (char '%')
390 infixMachOp8 _ = Nothing
392 pprExpr9 :: CmmExpr -> SDoc
395 CmmLit lit -> pprLit1 lit
396 CmmLoad expr rep -> ppr rep <> brackets( ppr expr )
397 CmmReg reg -> ppr reg
398 CmmRegOff reg off -> parens (ppr reg <+> char '+' <+> int off)
399 CmmMachOp mop args -> genMachOp mop args
401 genMachOp :: MachOp -> [CmmExpr] -> SDoc
403 | Just doc <- infixMachOp mop = case args of
405 [x,y] -> pprExpr9 x <+> doc <+> pprExpr9 y
408 [x] -> doc <> pprExpr9 x
410 _ -> pprTrace "PprCmm.genMachOp: machop with strange number of args"
412 parens (hcat $ punctuate comma (map pprExpr args)))
415 | isJust (infixMachOp1 mop)
416 || isJust (infixMachOp7 mop)
417 || isJust (infixMachOp8 mop) = parens (pprExpr (CmmMachOp mop args))
419 | otherwise = char '%' <> ppr_op <> parens (commafy (map pprExpr args))
420 where ppr_op = text (map (\c -> if c == ' ' then '_' else c)
422 -- replace spaces in (show mop) with underscores,
425 -- Unsigned ops on the word size of the machine get nice symbols.
426 -- All else get dumped in their ugly format.
428 infixMachOp :: MachOp -> Maybe SDoc
431 MO_And _ -> Just $ char '&'
432 MO_Or _ -> Just $ char '|'
433 MO_Xor _ -> Just $ char '^'
434 MO_Not _ -> Just $ char '~'
435 MO_S_Neg _ -> Just $ char '-' -- there is no unsigned neg :)
438 -- --------------------------------------------------------------------------
440 -- To minimise line noise we adopt the convention that if the literal
441 -- has the natural machine word size, we do not append the type
443 pprLit :: CmmLit -> SDoc
444 pprLit lit = case lit of
446 hcat [ (if i < 0 then parens else id)(integer i)
449 else space <> dcolon <+> ppr rep) ]
451 CmmFloat f rep -> hsep [ rational f, dcolon, ppr rep ]
452 CmmLabel clbl -> pprCLabel clbl
453 CmmLabelOff clbl i -> pprCLabel clbl <> ppr_offset i
454 CmmLabelDiffOff clbl1 clbl2 i -> pprCLabel clbl1 <> char '-'
455 <> pprCLabel clbl2 <> ppr_offset i
457 pprLit1 lit@(CmmLabelOff clbl i) = parens (pprLit lit)
458 pprLit1 lit = pprLit lit
460 ppr_offset :: Int -> SDoc
463 | i>=0 = char '+' <> int i
464 | otherwise = char '-' <> int (-i)
466 -- --------------------------------------------------------------------------
468 -- Strings are printed as C strings, and we print them as I8[],
471 pprStatic :: CmmStatic -> SDoc
472 pprStatic s = case s of
473 CmmStaticLit lit -> nest 4 $ ptext SLIT("const") <+> pprLit lit <> semi
474 CmmUninitialised i -> nest 4 $ text "I8" <> brackets (int i)
475 CmmAlign i -> nest 4 $ text "align" <+> int i
476 CmmDataLabel clbl -> pprCLabel clbl <> colon
477 CmmString s' -> nest 4 $ text "I8[]" <+> text (show s')
479 -- --------------------------------------------------------------------------
480 -- Registers, whether local (temps) or global
482 pprReg :: CmmReg -> SDoc
485 CmmLocal local -> pprLocalReg local
486 CmmGlobal global -> pprGlobalReg global
489 -- We only print the type of the local reg if it isn't wordRep
491 pprLocalReg :: LocalReg -> SDoc
492 pprLocalReg (LocalReg uniq rep follow)
493 = hcat [ char '_', ppr uniq, ty ] where
494 ty = if rep == wordRep && follow == KindNonPtr
496 else dcolon <> ptr <> ppr rep
497 ptr = if follow == KindNonPtr
499 else doubleQuotes (text "ptr")
501 -- needs to be kept in syn with Cmm.hs.GlobalReg
503 pprGlobalReg :: GlobalReg -> SDoc
506 VanillaReg n -> char 'R' <> int n
507 FloatReg n -> char 'F' <> int n
508 DoubleReg n -> char 'D' <> int n
509 LongReg n -> char 'L' <> int n
510 Sp -> ptext SLIT("Sp")
511 SpLim -> ptext SLIT("SpLim")
512 Hp -> ptext SLIT("Hp")
513 HpLim -> ptext SLIT("HpLim")
514 CurrentTSO -> ptext SLIT("CurrentTSO")
515 CurrentNursery -> ptext SLIT("CurrentNursery")
516 HpAlloc -> ptext SLIT("HpAlloc")
517 GCEnter1 -> ptext SLIT("stg_gc_enter_1")
518 GCFun -> ptext SLIT("stg_gc_fun")
519 BaseReg -> ptext SLIT("BaseReg")
520 PicBaseReg -> ptext SLIT("PicBaseReg")
522 -- --------------------------------------------------------------------------
525 pprSection :: Section -> SDoc
526 pprSection s = case s of
527 Text -> section <+> doubleQuotes (ptext SLIT("text"))
528 Data -> section <+> doubleQuotes (ptext SLIT("data"))
529 ReadOnlyData -> section <+> doubleQuotes (ptext SLIT("readonly"))
530 RelocatableReadOnlyData
531 -> section <+> doubleQuotes (ptext SLIT("relreadonly"))
532 UninitialisedData -> section <+> doubleQuotes (ptext SLIT("uninitialised"))
533 OtherSection s' -> section <+> doubleQuotes (text s')
535 section = ptext SLIT("section")
537 -- --------------------------------------------------------------------------
540 pprBlockId :: BlockId -> SDoc
541 pprBlockId b = ppr $ getUnique b
543 -----------------------------------------------------------------------------
545 commafy :: [SDoc] -> SDoc
546 commafy xs = hsep $ punctuate comma xs