+
+
+----------------------------------------------------------------
+-- | The purpose of this function is to print a Cmm zipper graph "as if it were"
+-- a Cmm program. The objective is dodgy, so it's unsurprising parts of the
+-- code are dodgy as well.
+
+pprCmmGraphLikeCmm :: CmmGraph -> SDoc
+pprCmmGraphLikeCmm g = vcat (swallow blocks)
+ where blocks = Z.postorder_dfs g
+ swallow :: [CmmBlock] -> [SDoc]
+ swallow [] = []
+ swallow (Z.Block id t : rest) = tail id [] Nothing t rest
+ tail id prev' out (Z.ZTail (CopyOut conv args) t) rest =
+ if isJust out then panic "multiple CopyOut nodes in one basic block"
+ else
+ tail id (prev') (Just (conv, args)) t rest
+ tail id prev' out (Z.ZTail m t) rest = tail id (mid m : prev') out t rest
+ tail id prev' out (Z.ZLast Z.LastExit) rest = exit id prev' out rest
+ tail id prev' out (Z.ZLast (Z.LastOther l)) rest = last id prev' out l rest
+ mid (CopyIn _ [] _) = text "// proc point (no parameters)"
+ mid m@(CopyIn {}) = ppr m <+> text "(proc point)"
+ mid m = ppr m
+ block' id prev'
+ | id == Z.lg_entry g, entry_has_no_pred =
+ vcat (text "<entry>" : reverse prev')
+ | otherwise = hang (ppr id <> colon) 4 (vcat (reverse prev'))
+ last id prev' out l n =
+ let endblock stmt = block' id (stmt : prev') : swallow n in
+ case l of
+ LastBranch tgt ->
+ case n of
+ Z.Block id' t : bs
+ | tgt == id', unique_pred id'
+ -> tail id prev' out t bs -- optimize out redundant labels
+ _ -> endblock (ppr $ CmmBranch tgt)
+ l@(LastCondBranch expr tid fid) ->
+ let ft id = text "// fall through to " <> ppr id in
+ case n of
+ Z.Block id' t : bs
+ | id' == fid, isNothing out ->
+ tail id (ft fid : ppr (CmmCondBranch expr tid) : prev') Nothing t bs
+ | id' == tid, Just e' <- maybeInvertCmmExpr expr, isNothing out->
+ tail id (ft tid : ppr (CmmCondBranch e' fid) : prev') Nothing t bs
+ _ -> endblock $ with_out out l
+ l@(LastJump {}) -> endblock $ with_out out l
+ l@(LastReturn {}) -> endblock $ with_out out l
+ l@(LastSwitch {}) -> endblock $ with_out out l
+ l@(LastCall _ Nothing) -> endblock $ with_out out l
+ l@(LastCall tgt (Just k))
+ | Z.Block id' (Z.ZTail (CopyIn _ ress srt) t) : bs <- n,
+ Just (conv, args) <- out,
+ id' == k ->
+ let call = CmmCall tgt' ress args (CmmSafe srt) CmmMayReturn
+ tgt' = CmmCallee tgt (cconv_of_conv conv)
+ ppcall = ppr call <+> parens (text "ret to" <+> ppr k)
+ in if unique_pred k then
+ tail id (ppcall : prev') Nothing t bs
+ else
+ endblock (ppcall)
+ | Z.Block id' t : bs <- n, id' == k, unique_pred k,
+ Just (conv, args) <- out,
+ Just (ress, srt) <- findCopyIn t ->
+ let call = CmmCall tgt' ress args (CmmSafe srt) CmmMayReturn
+ tgt' = CmmCallee tgt (cconv_of_conv conv)
+ delayed =
+ ptext (sLit "// delayed CopyIn follows previous call")
+ in tail id (delayed : ppr call : prev') Nothing t bs
+ | otherwise -> endblock $ with_out out l
+ findCopyIn (Z.ZTail (CopyIn _ ress srt) _) = Just (ress, srt)
+ findCopyIn (Z.ZTail _ t) = findCopyIn t
+ findCopyIn (Z.ZLast _) = Nothing
+ exit id prev' out n = -- highly irregular (assertion violation?)
+ let endblock stmt = block' id (stmt : prev') : swallow n in
+ case out of Nothing -> endblock (text "// <exit>")
+ Just (conv, args) -> endblock (ppr (CopyOut conv args) $$
+ text "// <exit>")
+ preds = zipPreds g
+ entry_has_no_pred = case Z.lookupBlockEnv preds (Z.lg_entry g) of
+ Nothing -> True
+ Just s -> isEmptyUniqSet s
+ single_preds =
+ let add b single =
+ let id = Z.blockId b
+ in case Z.lookupBlockEnv preds id of
+ Nothing -> single
+ Just s -> if sizeUniqSet s == 1 then
+ Z.extendBlockSet single id
+ else single
+ in Z.fold_blocks add Z.emptyBlockSet g
+ unique_pred id = Z.elemBlockSet id single_preds
+ cconv_of_conv (ConventionStandard conv _) = conv
+ cconv_of_conv (ConventionPrivate {}) = CmmCallConv -- XXX totally bogus
+
+with_out :: Maybe (Convention, CmmActuals) -> Last -> SDoc
+with_out Nothing l = ptext (sLit "??no-arguments??") <+> ppr l
+with_out (Just (conv, args)) l = last l
+ where last (LastCall e k) =
+ hcat [ptext (sLit "... = foreign "),
+ doubleQuotes(ppr conv), space,
+ ppr_target e, parens ( commafy $ map ppr args ),
+ ptext (sLit " \"safe\""),
+ case k of Nothing -> ptext (sLit " never returns")
+ Just _ -> empty,
+ semi ]
+ last (LastReturn) = ppr (CmmReturn args)
+ last (LastJump e) = ppr (CmmJump e args)
+ last l = ppr (CopyOut conv args) $$ ppr l
+ ppr_target (CmmLit lit) = ppr lit
+ ppr_target fn' = parens (ppr fn')
+ commafy xs = hsep $ punctuate comma xs
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