language-c-0.3.2.1: Analysis and generation of C code

Portability | ghc
Stability | alpha
Maintainer | benedikt.huber@gmail.com

Language.C.Analysis.TravMonad

Contents

- AST traversal monad
- Handling declarations
- Symbol table scope modification
- Symbol table lookup (delegate)
- Symbol table modification
- Additional error handling facilities
- Trav - default MonadTrav implementation
- Helpers

Description

Monad for Traversals of the C AST.

For the traversal, we maintain a symboltable and need MonadError and unique name generation facilities. Furthermore, the user may provide callbacks to handle declarations and definitions.

Synopsis

- class Monad m => MonadTrav m where
  - throwTravError :: Error e => e -> m a
  - catchTravError :: m a -> (CError -> m a) -> m a
  - recordError :: Error e => e -> m ()
  - getErrors :: m [CError]
  - getDefTable :: m DefTable
  - withDefTable :: (DefTable -> (a, DefTable)) -> m a
  - genName :: m Name
  - handleDecl :: DeclEvent -> m ()
- handleTagDecl :: MonadTrav m => TagFwdDecl -> m ()
- handleTagDef :: MonadTrav m => TagDef -> m ()
- handleEnumeratorDef :: MonadTrav m => Enumerator -> m ()
- handleTypeDef :: MonadTrav m => TypeDef -> m ()
- handleObjectDef :: MonadTrav m => Ident -> ObjDef -> m ()
- handleFunDef :: MonadTrav m => Ident -> FunDef -> m ()
- handleVarDecl :: MonadTrav m => Decl -> m ()
- handleParamDecl :: MonadTrav m => ParamDecl -> m ()
- handleAsmBlock :: MonadTrav m => AsmBlock -> m ()
- enterPrototypeScope :: MonadTrav m => m ()
- leavePrototypeScope :: MonadTrav m => m ()
- enterFunctionScope :: MonadTrav m => m ()
- leaveFunctionScope :: MonadTrav m => m ()
- enterBlockScope :: MonadTrav m => m ()
- leaveBlockScope :: MonadTrav m => m ()
- lookupTypeDef :: MonadTrav m => Ident -> m Type
- lookupObject :: MonadTrav m => Ident -> m (Maybe IdentDecl)
- createSUERef :: MonadTrav m => NodeInfo -> Maybe Ident -> m SUERef
- hadHardErrors :: [CError] -> Bool
- handleTravError :: MonadTrav m => m a -> m (Maybe a)
- throwOnLeft :: (MonadTrav m, Error e) => Either e a -> m a
- astError :: MonadTrav m => NodeInfo -> String -> m a
- warn :: (Error e, MonadTrav m) => e -> m ()
- data Trav s a
- runTrav :: forall s a. s -> Trav s a -> Either [CError] (a, TravState s)
- runTrav_ :: Trav () a -> Either [CError] (a, [CError])
- data TravState s
- initTravState :: s -> TravState s
- withExtDeclHandler :: Trav s a -> (DeclEvent -> Trav s ()) -> Trav s a
- modifyUserState :: (s -> s) -> Trav s ()
- userState :: TravState s -> s
- travErrors :: TravState s -> [CError]
- mapMaybeM :: Monad m => Maybe a -> (a -> m b) -> m (Maybe b)
- maybeM :: Monad m => Maybe a -> (a -> m ()) -> m ()
- mapSndM :: Monad m => (b -> m c) -> (a, b) -> m (a, c)
- concatMapM :: Monad m => (a -> m [b]) -> [a] -> m [b]

# AST traversal monad

class Monad m => MonadTrav m where

Traversal monad

Methods

throwTravError :: Error e => e -> m a

throw an `Error`

catchTravError :: m a -> (CError -> m a) -> m a

catch an `Error` (we could implement dynamically-typed catch here)

recordError :: Error e => e -> m ()

remember that an `Error` occured (without throwing it)

getErrors :: m [CError]

return the list of recorded errors

getDefTable :: m DefTable

return the definition table

withDefTable :: (DefTable -> (a, DefTable)) -> m a

perform an action modifying the definition table

genName :: m Name

unique name generation

handleDecl :: DeclEvent -> m ()

handling declarations and definitions

Instances

MonadTrav (Trav s) |

# Handling declarations

handleTagDecl :: MonadTrav m => TagFwdDecl -> m ()

forward declaration of a tag. Only neccessary for name analysis, but otherwise no semantic consequences.

handleTagDef :: MonadTrav m => TagDef -> m ()

define the given composite type or enumeration If there is a declaration visible, overwrite it with the definition. Otherwise, enter a new definition in the current namespace. If there is already a definition present, yield an error (redeclaration).

handleEnumeratorDef :: MonadTrav m => Enumerator -> m ()

handleTypeDef :: MonadTrav m => TypeDef -> m ()

handleObjectDef :: MonadTrav m => Ident -> ObjDef -> m ()

handle object defintions (maybe tentative)

handleFunDef :: MonadTrav m => Ident -> FunDef -> m ()

handle function definitions

handleVarDecl :: MonadTrav m => Decl -> m ()

handle variable declarations (external object declarations and function prototypes) variable declarations are either function prototypes, or external declarations, and not very interesting on their own. we only put them in the symbol table and call the handle. declarations never override definitions

handleParamDecl :: MonadTrav m => ParamDecl -> m ()

handle parameter declaration. The interesting part is that parameters can be abstract (if they are part of a type). If they have a name, we enter the name (usually in function prototype or function scope), checking if there are duplicate definitions. FIXME: I think it would be more transparent to handle parameter declarations in a special way

handleAsmBlock :: MonadTrav m => AsmBlock -> m ()

# Symbol table scope modification

enterPrototypeScope :: MonadTrav m => m ()

leavePrototypeScope :: MonadTrav m => m ()

enterFunctionScope :: MonadTrav m => m ()

leaveFunctionScope :: MonadTrav m => m ()

enterBlockScope :: MonadTrav m => m ()

leaveBlockScope :: MonadTrav m => m ()

# Symbol table lookup (delegate)

lookupTypeDef :: MonadTrav m => Ident -> m Type

lookup a type definition the 'wrong kind of object' is an internal error here, because the parser should distinguish typeDefs and other objects

lookupObject :: MonadTrav m => Ident -> m (Maybe IdentDecl)

lookup an object, function or enumerator

# Symbol table modification

createSUERef :: MonadTrav m => NodeInfo -> Maybe Ident -> m SUERef

create a reference to a struct/union/enum

This currently depends on the fact the structs are tagged with unique names. We could use the name generation of TravMonad as well, which might be the better choice when dealing with autogenerated code.

# Additional error handling facilities

hadHardErrors :: [CError] -> Bool

check wheter non-recoverable errors occured

handleTravError :: MonadTrav m => m a -> m (Maybe a)

throwOnLeft :: (MonadTrav m, Error e) => Either e a -> m a

raise an error based on an Either argument

astError :: MonadTrav m => NodeInfo -> String -> m a

raise an error caused by a malformed AST

warn :: (Error e, MonadTrav m) => e -> m ()

# Trav - default MonadTrav implementation

data Trav s a

simple traversal monad, providing user state and callbacks

Instances

Monad (Trav s) |
MonadTrav (Trav s) |

runTrav :: forall s a. s -> Trav s a -> Either [CError] (a, TravState s)

runTrav_ :: Trav () a -> Either [CError] (a, [CError])

data TravState s

initTravState :: s -> TravState s

withExtDeclHandler :: Trav s a -> (DeclEvent -> Trav s ()) -> Trav s a

modifyUserState :: (s -> s) -> Trav s ()

userState :: TravState s -> s

travErrors :: TravState s -> [CError]

# Helpers

mapMaybeM :: Monad m => Maybe a -> (a -> m b) -> m (Maybe b)

maybeM :: Monad m => Maybe a -> (a -> m ()) -> m ()

mapSndM :: Monad m => (b -> m c) -> (a, b) -> m (a, c)

concatMapM :: Monad m => (a -> m [b]) -> [a] -> m [b]