GHC.Driver.Main

Main API for compiling plain Haskell source code.

This module implements compilation of a Haskell source. It is not concerned with preprocessing of source files; this is handled in GHC.Driver.Pipeline

There are various entry points depending on what mode we're in: "batch" mode (--make), "one-shot" mode (-c, -S etc.), and "interactive" mode (GHCi). There are also entry points for individual passes: parsing, typechecking/renaming, desugaring, and simplification.

All the functions here take an HscEnv as a parameter, but none of them return a new one: HscEnv is treated as an immutable value from here on in (although it has mutable components, for the caches).

We use the Hsc monad to deal with warning messages consistently: specifically, while executing within an Hsc monad, warnings are collected. When a Hsc monad returns to an IO monad, the warnings are printed, or compilation aborts if the -Werror flag is enabled.

(c) The GRASP/AQUA Project, Glasgow University, 1993-2000

Making an HscEnv

newHscEnv :: DynFlags -> IO HscEnv

Compiling complete source files

type Messager = HscEnv -> (Int, Int) -> RecompileRequired -> ModSummary -> IO ()

batchMsg :: Messager

data HscStatus

Status of a compilation to hard-code

Constructors

HscNotGeneratingCode ModIface ModDetails

Nothing to do.

HscUpToDate ModIface ModDetails

Nothing to do because code already exists.

HscUpdateBoot ModIface ModDetails

Update boot file result.

HscUpdateSig ModIface ModDetails

Generate signature file (backpack)

HscRecomp

Recompile this module.

Fields

• hscs_guts :: CgGuts

  Information for the code generator.

• hscs_mod_location :: !ModLocation

  Module info

• hscs_partial_iface :: !PartialModIface

  Partial interface

• hscs_old_iface_hash :: !(Maybe Fingerprint)

  Old interface hash for this compilation, if an old interface file exists. Pass to hscMaybeWriteIface when writing the interface to avoid updating the existing interface when the interface isn't changed.

• hscs_iface_dflags :: !DynFlags

  Generate final iface using this DynFlags. FIXME (osa): I don't understand why this is necessary, but I spent almost two days trying to figure this out and I couldn't .. perhaps someone who understands this code better will remove this later.

hscIncrementalCompile :: Bool -> Maybe TcGblEnv -> Maybe Messager -> HscEnv -> ModSummary -> SourceModified -> Maybe ModIface -> (Int, Int) -> IO (HscStatus, DynFlags)

Used by both OneShot and batch mode. Runs the pipeline HsSyn and Core parts of the pipeline. We return a interface if we already had an old one around and recompilation was not needed. Otherwise it will be created during later passes when we run the compilation pipeline.

initModDetails :: HscEnv -> ModSummary -> ModIface -> IO ModDetails

hscMaybeWriteIface :: DynFlags -> ModIface -> Maybe Fingerprint -> ModLocation -> IO ()

hscCompileCmmFile :: HscEnv -> FilePath -> FilePath -> IO ()

hscGenHardCode

Arguments

:: HscEnv

-> CgGuts

-> ModLocation

-> FilePath

-> IO (FilePath, Maybe FilePath, [(ForeignSrcLang, FilePath)], CgInfos)

Just f = _stub.c is f

Compile to hard-code.

hscInteractive :: HscEnv -> CgGuts -> ModLocation -> IO (Maybe FilePath, CompiledByteCode, [SptEntry])

Running passes separately

hscParse :: HscEnv -> ModSummary -> IO HsParsedModule

parse a file, returning the abstract syntax

hscTypecheckRename :: HscEnv -> ModSummary -> HsParsedModule -> IO (TcGblEnv, RenamedStuff)

Rename and typecheck a module, additionally returning the renamed syntax

hscDesugar :: HscEnv -> ModSummary -> TcGblEnv -> IO ModGuts

Convert a typechecked module to Core

makeSimpleDetails :: HscEnv -> TcGblEnv -> IO ModDetails

Make a ModDetails from the results of typechecking. Used when typechecking only, as opposed to full compilation.

hscSimplify :: HscEnv -> [String] -> ModGuts -> IO ModGuts

Safe Haskell

hscCheckSafe :: HscEnv -> Module -> SrcSpan -> IO Bool

Check that a module is safe to import.

We return True to indicate the import is safe and False otherwise although in the False case an exception may be thrown first.

hscGetSafe :: HscEnv -> Module -> SrcSpan -> IO (Bool, Set UnitId)

Return if a module is trusted and the pkgs it depends on to be trusted.

Support for interactive evaluation

hscParseIdentifier :: HscEnv -> String -> IO (Located RdrName)

hscTcRcLookupName :: HscEnv -> Name -> IO (Maybe TyThing)

hscTcRnGetInfo :: HscEnv -> Name -> IO (Maybe (TyThing, Fixity, [ClsInst], [FamInst], SDoc))

hscIsGHCiMonad :: HscEnv -> String -> IO Name

hscGetModuleInterface :: HscEnv -> Module -> IO ModIface

hscRnImportDecls :: HscEnv -> [LImportDecl GhcPs] -> IO GlobalRdrEnv

Rename some import declarations

hscTcRnLookupRdrName :: HscEnv -> Located RdrName -> IO [Name]

Lookup things in the compiler's environment

hscStmt :: HscEnv -> String -> IO (Maybe ([Id], ForeignHValue, FixityEnv))

Compile a stmt all the way to an HValue, but don't run it

We return Nothing to indicate an empty statement (or comment only), not a parse error.

hscParseStmtWithLocation :: String -> Int -> String -> Hsc (Maybe (GhciLStmt GhcPs))

hscStmtWithLocation

Arguments

:: HscEnv

-> String

The statement

-> String

The source

-> Int

Starting line

-> IO (Maybe ([Id], ForeignHValue, FixityEnv))

Compile a stmt all the way to an HValue, but don't run it

We return Nothing to indicate an empty statement (or comment only), not a parse error.

hscParsedStmt

Arguments

:: HscEnv

-> GhciLStmt GhcPs

The parsed statement

-> IO (Maybe ([Id], ForeignHValue, FixityEnv))

hscDecls

Arguments

:: HscEnv

-> String

The statement

-> IO ([TyThing], InteractiveContext)

Compile a decls

hscParseDeclsWithLocation :: HscEnv -> String -> Int -> String -> IO [LHsDecl GhcPs]

hscDeclsWithLocation

Arguments

:: HscEnv

-> String

The statement

-> String

The source

-> Int

Starting line

-> IO ([TyThing], InteractiveContext)

Compile a decls

hscParsedDecls :: HscEnv -> [LHsDecl GhcPs] -> IO ([TyThing], InteractiveContext)

hscTcExpr

Arguments

:: HscEnv

-> TcRnExprMode

-> String

The expression

-> IO Type

Typecheck an expression (but don't run it)

data TcRnExprMode

How should we infer a type? See Note [TcRnExprMode]

Constructors

TM_Inst

Instantiate the type fully (:type)

TM_NoInst

Do not instantiate the type (:type +v)

TM_Default

Default the type eagerly (:type +d)

hscImport :: HscEnv -> String -> IO (ImportDecl GhcPs)

hscKcType

Arguments

:: HscEnv

-> Bool

Normalise the type

-> String

The type as a string

-> IO (Type, Kind)

Resulting type (possibly normalised) and kind

Find the kind of a type, after generalisation

hscParseExpr :: String -> Hsc (LHsExpr GhcPs)

hscParseType :: String -> Hsc (LHsType GhcPs)

hscCompileCoreExpr :: HscEnv -> SrcSpan -> CoreExpr -> IO ForeignHValue

Low-level exports for hooks

hscCompileCoreExpr' :: HscEnv -> SrcSpan -> CoreExpr -> IO ForeignHValue

hscParse' :: ModSummary -> Hsc HsParsedModule

hscSimplify' :: [String] -> ModGuts -> Hsc ModGuts

hscDesugar' :: ModLocation -> TcGblEnv -> Hsc ModGuts

tcRnModule' :: ModSummary -> Bool -> HsParsedModule -> Hsc TcGblEnv

doCodeGen :: HscEnv -> Module -> [TyCon] -> CollectedCCs -> [StgTopBinding] -> HpcInfo -> IO (Stream IO CmmGroupSRTs CgInfos)

getHscEnv :: Hsc HscEnv

hscSimpleIface' :: TcGblEnv -> Maybe Fingerprint -> Hsc (ModIface, Maybe Fingerprint, ModDetails)

oneShotMsg :: HscEnv -> RecompileRequired -> IO ()

dumpIfaceStats :: HscEnv -> IO ()

ioMsgMaybe :: IO (Messages, Maybe a) -> Hsc a

Deal with errors and warnings returned by a compilation step

In order to reduce dependencies to other parts of the compiler, functions outside the "main" parts of GHC return warnings and errors as a parameter and signal success via by wrapping the result in a Maybe type. This function logs the returned warnings and propagates errors as exceptions (of type SourceError).

This function assumes the following invariants:

1. If the second result indicates success (is of the form 'Just x'), there must be no error messages in the first result.
2. If there are no error messages, but the second result indicates failure there should be warnings in the first result. That is, if the action failed, it must have been due to the warnings (i.e., -Werror).

showModuleIndex :: (Int, Int) -> String

hscAddSptEntries :: HscEnv -> [SptEntry] -> IO ()

Load the given static-pointer table entries into the interpreter. See Note [Grand plan for static forms] in GHC.Iface.Tidy.StaticPtrTable.