Alan Zimmerman pushed to branch wip/az/ghc-cpp at Glasgow Haskell Compiler / GHC Commits: 58b88790 by Alan Zimmerman at 2025-06-22T21:41:14+01:00 Use PPM as Maybe inside PP - - - - - 2 changed files: - compiler/GHC/Parser/PreProcess/Macro.hs - compiler/GHC/Parser/PreProcess/State.hs Changes: ===================================== compiler/GHC/Parser/PreProcess/Macro.hs ===================================== @@ -35,97 +35,90 @@ details import Data.List (intercalate) import Data.Map qualified as Map import Data.Maybe - import Data.Semigroup qualified as S -import GHC.Driver.Errors.Types (PsMessage) -import GHC.Parser.Lexer qualified as Lexer + +import GHC.Base +import GHC.Parser.Lexer (P (..), PState (..), ParseResult (..)) import GHC.Parser.PreProcess.Eval import GHC.Parser.PreProcess.ParsePP import GHC.Parser.PreProcess.Parser qualified as Parser import GHC.Parser.PreProcess.ParserM import GHC.Parser.PreProcess.State import GHC.Prelude -import GHC.Types.Error (MsgEnvelope) import GHC.Types.SrcLoc import GHC.Utils.Outputable import GHC.Utils.Panic (panic) -- --------------------------------------------------------------------- --- We evaluate to an Int, which we convert to a bool +-- We evaluate to an Int, which we convert to a bool cppCond :: SrcSpan -> String -> PP Bool cppCond loc str = do - s <- getPpState + r <- runPM $ cppCond' loc str + return $ fromMaybe False r + +cppCond' :: SrcSpan -> String -> PPM Bool +cppCond' loc str = do + s <- liftPM getPpState expanded <- expand loc (pp_defines s) str - case expanded of + v <- case Parser.parseExpr expanded of Left err -> do - Lexer.addError err - return False - Right expanded -> do - v <- case Parser.parseExpr expanded of - Left err -> do - let detail = - if str == expanded || expanded == "" - then - [ text str - ] - else - [ text expanded - , text "expanded from:" - , text str - ] - addGhcCPPError' - loc - "Error evaluating CPP condition:" - ( text err - <+> text "of" - $+$ vcat detail - ) - return 0 - Right tree -> return (eval tree) - return (toBool v) + let detail = + if str == expanded || expanded == "" + then + [text str] + else + [ text expanded + , text "expanded from:" + , text str + ] + liftPM $ + addGhcCPPError' + loc + "Error evaluating CPP condition:" + ( text err + <+> text "of" + $+$ vcat detail + ) + return 0 + Right tree -> return (eval tree) + return (toBool v) -- --------------------------------------------------------------------- -expand :: SrcSpan -> MacroDefines -> String -> PP (Either (MsgEnvelope PsMessage) String) +expand :: SrcSpan -> MacroDefines -> String -> PPM String expand loc s str = do case cppLex False str of Left err -> do - return - ( Left $ - mkGhcCPPError' - loc - "Error evaluating CPP condition:" - (text err <+> text "of" $+$ text str) - ) + liftPM $ + addGhcCPPError' + loc + "Error evaluating CPP condition:" + (text err <+> text "of" $+$ text str) + failPM Right tks -> do - expandedToks <- expandToks loc maxExpansions s tks - case expandedToks of - Left err -> return (Left err) - Right toks -> return $ Right $ combineToks $ map t_str toks + toks <- expandToks loc maxExpansions s tks + return $ combineToks $ map t_str toks maxExpansions :: Int maxExpansions = 15 -expandToks :: SrcSpan -> Int -> MacroDefines -> [Token] -> PP (Either (MsgEnvelope PsMessage) [Token]) +expandToks :: SrcSpan -> Int -> MacroDefines -> [Token] -> PPM [Token] expandToks loc 0 _ ts = do - return $ - Left $ - mkGhcCPPError' - loc - "CPP macro expansion limit hit:" - (text (combineToks $ map t_str ts)) + liftPM $ + addGhcCPPError' + loc + "CPP macro expansion limit hit:" + (text (combineToks $ map t_str ts)) + failPM expandToks loc cnt s ts = do - expansion <- doExpandToks loc False s ts - case expansion of - Left err -> return (Left err) - Right (!expansionDone, !r) -> - if expansionDone - then expandToks loc (cnt - 1) s r - else return (Right r) - -doExpandToks :: SrcSpan -> Bool -> MacroDefines -> [Token] -> PP (Either (MsgEnvelope PsMessage) (Bool, [Token])) -doExpandToks _loc ed _ [] = return $ Right (ed, []) + (!expansionDone, !r) <- doExpandToks loc False s ts + if expansionDone + then expandToks loc (cnt - 1) s r + else return r + +doExpandToks :: SrcSpan -> Bool -> MacroDefines -> [Token] -> PPM (Bool, [Token]) +doExpandToks _loc ed _ [] = return (ed, []) doExpandToks loc ed s (TIdentifierLParen n : ts) = -- TIdentifierLParen has no meaning here (only in a #define), so -- restore it to its constituent tokens @@ -136,26 +129,26 @@ doExpandToks loc _ s (TIdentifier "defined" : ts) = do case expandedArgs of (Just [[TIdentifier macro_name]], rest0) -> case Map.lookup macro_name s of - Nothing -> return $ Right (True, TInteger "0" : rest0) - Just _ -> return $ Right (True, TInteger "1" : rest0) + Nothing -> return (True, TInteger "0" : rest0) + Just _ -> return (True, TInteger "1" : rest0) (Nothing, TIdentifier macro_name : ts0) -> case Map.lookup macro_name s of - Nothing -> return $ Right (True, TInteger "0" : ts0) - Just _ -> return $ Right (True, TInteger "1" : ts0) + Nothing -> return (True, TInteger "0" : ts0) + Just _ -> return (True, TInteger "1" : ts0) (Nothing, _) -> do - return $ - Left $ - mkGhcCPPError' - loc - "CPP defined: expected an identifier, got:" - (text (concatMap t_str ts)) + liftPM $ + addGhcCPPError' + loc + "CPP defined: expected an identifier, got:" + (text (concatMap t_str ts)) + failPM -- TODO:AZ make part of addGhcCPPError'? (Just args, _) -> do - return $ - Left $ - mkGhcCPPError' - loc - "CPP defined: expected a single arg, got:" - (text (intercalate "," (map (concatMap t_str) args))) + liftPM $ + addGhcCPPError' + loc + "CPP defined: expected a single arg, got:" + (text (intercalate "," (map (concatMap t_str) args))) + failPM -- TODO:AZ make part of addGhcCPPError'? doExpandToks loc ed s (TIdentifier n : ts) = do (args, rest0) <- getExpandArgs loc ts let @@ -168,15 +161,11 @@ doExpandToks loc ed s (TIdentifier n : ts) = do (ed0, r, rest1) = case m_args of Nothing -> (True, rhs, ts) Just _ -> (True, replace_args args m_args rhs, rest0) - expansion <- doExpandToks loc ed' s ts' - case expansion of - Left err -> return $ Left err - Right (ed'', rest) -> return $ Right (ed'', expanded ++ rest) + (ed'', rest) <- doExpandToks loc ed' s ts' + return (ed'', expanded ++ rest) doExpandToks loc ed s (t : ts) = do - expansion <- doExpandToks loc ed s ts - case expansion of - Left err -> return (Left err) - Right (ed', r) -> return $ Right (ed', t : r) + (ed', r) <- doExpandToks loc ed s ts + return (ed', t : r) {- Note: ['defined' unary operator] @@ -248,14 +237,15 @@ inner parentheses do not separate arguments. {- | Look for possible arguments to a macro expansion. The only thing we look for are commas, open parens, and close parens. -} -getExpandArgs :: SrcSpan -> [Token] -> PP (Maybe [[Token]], [Token]) +getExpandArgs :: SrcSpan -> [Token] -> PPM (Maybe [[Token]], [Token]) getExpandArgs loc ts = case pArgs ts of Left err -> do - addGhcCPPError' - loc - "CPP: cannot expand macro arguments:" - (text err <+> text "in" $+$ text (concatMap t_str ts)) + liftPM $ + addGhcCPPError' + loc + "CPP: cannot expand macro arguments:" + (text err <+> text "in" $+$ text (concatMap t_str ts)) return (Nothing, ts) Right r -> return r @@ -336,6 +326,65 @@ isOther (TOpenParen _) = False isOther (TCloseParen _) = False isOther _ = True +-- --------------------------------------------------------------------- + +-- | Wrapper around P Monad to include a Maybe result +type PPM = PM PpState +-- See Note [PPM Monad] + +newtype PM p a = PM {unPM :: PState p -> ParseResult p (Maybe a)} + +instance Functor (PM p) where + fmap = liftM + +instance Applicative (PM p) where + pure = returnP + (<*>) = ap + +instance Monad (PM p) where + (>>=) = thenP + +returnP :: a -> PM p a +returnP a = a `seq` (PM $ \s -> POk s (Just a)) + +failPM :: PM p a +failPM = PM $ \s -> POk s Nothing + +thenP :: PM p a -> (a -> PM p b) -> PM p b +(PM m) `thenP` k = PM $ \s -> + case m s of + POk s1 Nothing -> POk s1 Nothing + POk s1 (Just a) -> (unPM (k a)) s1 + PFailed s1 -> PFailed s1 + +runPM :: PM p a -> P p (Maybe a) +runPM m = P $ \s -> (unPM m) s + +liftPM :: P p a -> PM p a +liftPM m = PM $ \s -> case (unP m) s of + POk s1 a -> POk s1 (Just a) + PFailed s1 -> PFailed s1 + +{- +Note [PPM Monad] +~~~~~~~~~~~~~~~~ + +The PPM monad is a combination of the Lexer P monad and the Maybe +monad. + +It is used when processing GHC_CPP macro conditionals, where we may +find an error processing the condition, such as a CPP parse error, +undefined macro, or similar. + +In this case we do not want to fail the overall GHC Parse, and simply +reporting the error and continuing is not enough, as the CPP +processing needs to be aware that there was a failure in the +processing, and not continue. In particular, this prevents reporting +additional CPP errors after the originating cause, and simplifies the +coding to not have to match on returned Maybe results +-} + + -- --------------------------------------------------------------------- m1 :: Either String [Token] ===================================== compiler/GHC/Parser/PreProcess/State.hs ===================================== @@ -32,10 +32,7 @@ module GHC.Parser.PreProcess.State ( ghcCppEnabled, setInLinePragma, getInLinePragma, - mkGhcCPPError', addGhcCPPError', - mkGhcCPPError, - addGhcCPPError, ) where import Data.List.NonEmpty ((<|)) @@ -59,6 +56,8 @@ import GHC.Utils.Outputable (hang, text, (<+>)) type PP = P PpState +-- --------------------------------------------------------------------- + data CppState = CppIgnoring | CppNormal @@ -268,7 +267,7 @@ parentScope = c :| [] -> c -- Perhaps should return enabled instead _ :| (h : _t) -> h in - POk s new_scope + POk s (new_scope) -- Get the current scope value getScope :: PP PpScope @@ -427,11 +426,11 @@ mkGhcCPPError' loc title detail = detail ) -addGhcCPPError' :: SrcSpan -> String -> SDoc -> P p () +addGhcCPPError' :: SrcSpan -> String -> SDoc -> PP () addGhcCPPError' loc title detail = Lexer.addError $ mkGhcCPPError' loc title detail mkGhcCPPError :: SrcSpan -> SDoc -> MsgEnvelope PsMessage mkGhcCPPError loc err = mkPlainErrorMsgEnvelope loc $ PsErrGhcCpp err -addGhcCPPError :: SrcSpan -> SDoc -> P p () +addGhcCPPError :: SrcSpan -> SDoc -> PP () addGhcCPPError loc err = Lexer.addError $ mkGhcCPPError loc err View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/58b88790c7f7484a9b1571d0a3e2b386... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/58b88790c7f7484a9b1571d0a3e2b386... 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