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

newHscEnvWithHUG :: DynFlags -> UnitId -> HomeUnitGraph -> IO HscEnv

Compiling complete source files

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

batchMsg :: Messager

batchMultiMsg :: Messager

data HscBackendAction

Action to perform in backend compilation

Constructors

HscUpdate ModIface

Update the boot and signature file results.

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.

Instances

Outputable HscBackendAction

Defined in GHC.Unit.Module.Status

Methods

ppr :: HscBackendAction -> SDoc

data HscRecompStatus

Status of a module in incremental compilation

Constructors

HscUpToDate ModIface (Maybe Linkable)

Nothing to do because code already exists.

HscRecompNeeded (Maybe Fingerprint)

Recompilation of module, or update of interface is required. Optionally pass the old interface hash to avoid updating the existing interface when it has not changed.

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

hscMaybeWriteIface

Arguments

:: Logger

-> DynFlags

-> Bool

Is this a simple interface generated after the core pipeline, or one with information from the backend? See: Note [Writing interface files]

-> ModIface

-> Maybe Fingerprint

The old interface hash, used to decide if we need to actually write the new interface.

-> ModLocation

-> IO ()

Write interface files

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

hscGenHardCode

Arguments

:: HscEnv

-> CgGuts

-> ModLocation

-> FilePath

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

Just f = _stub.c is f

Compile to hard-code.

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

Running passes separately

hscRecompStatus :: Maybe Messager -> HscEnv -> ModSummary -> Maybe ModIface -> Maybe Linkable -> (Int, Int) -> IO HscRecompStatus

Do the recompilation avoidance checks for both one-shot and --make modes This function is the *only* place in the compiler where we decide whether to recompile a module or not!

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

hscTypecheckAndGetWarnings :: HscEnv -> ModSummary -> IO (FrontendResult, WarningMessages)

Do Typechecking without throwing SourceError exception with -Werror

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

Convert a typechecked module to Core

makeSimpleDetails :: Logger -> 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

Run Core2Core simplifier. The list of String is a list of (Core) plugin module names added via TH (cf addCorePlugin).

hscDesugarAndSimplify :: ModSummary -> FrontendResult -> Messages GhcMessage -> Maybe Fingerprint -> Hsc HscBackendAction

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 (LocatedN 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 -> LocatedN 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)

hscParseModuleWithLocation :: HscEnv -> String -> Int -> String -> IO HsModule

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 inferred quantifiers only (:type)

TM_Default

Instantiate all quantifiers, and do eager defaulting (: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, [Linkable], PkgsLoaded)

hscTidy :: HscEnv -> ModGuts -> IO (CgGuts, ModDetails)

Low-level exports for hooks

hscCompileCoreExpr' :: HscEnv -> SrcSpan -> CoreExpr -> IO (ForeignHValue, [Linkable], PkgsLoaded)

hscParse' :: ModSummary -> Hsc HsParsedModule

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

Run Core2Core simplifier. The list of String is a list of (Core) plugin module names added via TH (cf addCorePlugin).

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

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

doCodeGen

Arguments

:: HscEnv

-> Module

-> InfoTableProvMap

-> [TyCon]

-> CollectedCCs

-> [CgStgTopBinding]

Bindings come already annotated with fvs

-> HpcInfo

-> IO (Stream IO CmmGroupSRTs CgInfos)

getHscEnv :: Hsc HscEnv

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

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

dumpIfaceStats :: HscEnv -> IO ()

ioMsgMaybe :: IO (Messages GhcMessage, 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) -> SDoc

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.

writeInterfaceOnlyMode :: DynFlags -> Bool