GHC.Cmm.CLabel

Documentation

data CLabel

CLabel is an abstract type that supports the following operations:

• Pretty printing
• In a C file, does it need to be declared before use? (i.e. is it guaranteed to be already in scope in the places we need to refer to it?)
• If it needs to be declared, what type (code or data) should it be declared to have?
• Is it visible outside this object file or not?
• Is it "dynamic" (see details below)
• Eq and Ord, so that we can make sets of CLabels (currently only used in outputting C as far as I can tell, to avoid generating more than one declaration for any given label).
• Converting an info table label into an entry label.

CLabel usage is a bit messy in GHC as they are used in a number of different contexts:

• By the C-- AST to identify labels
• By the unregisterised C code generator ("PprC") for naming functions (hence the name CLabel)
• By the native and LLVM code generators to identify labels

For extra fun, each of these uses a slightly different subset of constructors (e.g. AsmTempLabel and AsmTempDerivedLabel are used only in the NCG and LLVM backends).

In general, we use IdLabel to represent Haskell things early in the pipeline. However, later optimization passes will often represent blocks they create with LocalBlockLabel where there is no obvious Name to hang off the label.

Instances

Eq CLabel

Defined in GHC.Cmm.CLabel

Methods

(==) :: CLabel -> CLabel -> Bool

(/=) :: CLabel -> CLabel -> Bool

Ord CLabel

Defined in GHC.Cmm.CLabel

Methods

compare :: CLabel -> CLabel -> Ordering

(<) :: CLabel -> CLabel -> Bool

(<=) :: CLabel -> CLabel -> Bool

(>) :: CLabel -> CLabel -> Bool

(>=) :: CLabel -> CLabel -> Bool

max :: CLabel -> CLabel -> CLabel

min :: CLabel -> CLabel -> CLabel

Show CLabel

Defined in GHC.Cmm.CLabel

Methods

showsPrec :: Int -> CLabel -> ShowS

show :: CLabel -> String

showList :: [CLabel] -> ShowS

Outputable CLabel

Defined in GHC.Cmm.CLabel

Methods

ppr :: CLabel -> SDoc

OutputableP Platform CLabel

Defined in GHC.Cmm.CLabel

Methods

pdoc :: Platform -> CLabel -> SDoc

newtype NeedExternDecl

Indicate if GHC.CmmToC has to generate an extern declaration for the label (e.g. "extern StgWordArray(foo)"). The type is fixed to StgWordArray.

Symbols from the RTS don't need "extern" declarations because they are exposed via "rtsincludeStg.h" with the appropriate type. See needsCDecl.

The fixed StgWordArray type led to "conflicting types" issues with user provided Cmm files (not in the RTS) that declare data of another type (#15467 and test for #17920). Hence the Cmm parser considers that labels in data sections don't need the "extern" declaration (just add one explicitly if you need it).

See https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/compiler/backends/ppr-c#prototypes for why extern declaration are needed at all.

Constructors

NeedExternDecl Bool

Instances

Eq NeedExternDecl

Defined in GHC.Cmm.CLabel

Methods

(==) :: NeedExternDecl -> NeedExternDecl -> Bool

(/=) :: NeedExternDecl -> NeedExternDecl -> Bool

Ord NeedExternDecl

Defined in GHC.Cmm.CLabel

Methods

compare :: NeedExternDecl -> NeedExternDecl -> Ordering

(<) :: NeedExternDecl -> NeedExternDecl -> Bool

(<=) :: NeedExternDecl -> NeedExternDecl -> Bool

(>) :: NeedExternDecl -> NeedExternDecl -> Bool

(>=) :: NeedExternDecl -> NeedExternDecl -> Bool

max :: NeedExternDecl -> NeedExternDecl -> NeedExternDecl

min :: NeedExternDecl -> NeedExternDecl -> NeedExternDecl

data ForeignLabelSource

Record where a foreign label is stored.

Constructors

ForeignLabelInPackage UnitId

Label is in a named package

ForeignLabelInExternalPackage

Label is in some external, system package that doesn't also contain compiled Haskell code, and is not associated with any .hi files. We don't have to worry about Haskell code being inlined from external packages. It is safe to treat the RTS package as "external".

ForeignLabelInThisPackage

Label is in the package currently being compiled. This is only used for creating hacky tmp labels during code generation. Don't use it in any code that might be inlined across a package boundary (ie, core code) else the information will be wrong relative to the destination module.

Instances

Eq ForeignLabelSource

Defined in GHC.Cmm.CLabel

Methods

(==) :: ForeignLabelSource -> ForeignLabelSource -> Bool

(/=) :: ForeignLabelSource -> ForeignLabelSource -> Bool

Ord ForeignLabelSource

Defined in GHC.Cmm.CLabel

Methods

compare :: ForeignLabelSource -> ForeignLabelSource -> Ordering

(<) :: ForeignLabelSource -> ForeignLabelSource -> Bool

(<=) :: ForeignLabelSource -> ForeignLabelSource -> Bool

(>) :: ForeignLabelSource -> ForeignLabelSource -> Bool

(>=) :: ForeignLabelSource -> ForeignLabelSource -> Bool

max :: ForeignLabelSource -> ForeignLabelSource -> ForeignLabelSource

min :: ForeignLabelSource -> ForeignLabelSource -> ForeignLabelSource

Outputable ForeignLabelSource

Defined in GHC.Cmm.CLabel

Methods

ppr :: ForeignLabelSource -> SDoc

data DynamicLinkerLabelInfo

Constructors

CodeStub

SymbolPtr

GotSymbolPtr

GotSymbolOffset

Instances

Eq DynamicLinkerLabelInfo

Defined in GHC.Cmm.CLabel

Methods

(==) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

(/=) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

Ord DynamicLinkerLabelInfo

Defined in GHC.Cmm.CLabel

Methods

compare :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Ordering

(<) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

(<=) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

(>) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

(>=) :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> Bool

max :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo

min :: DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo -> DynamicLinkerLabelInfo

data ConInfoTableLocation

Which module is the info table from, and which number was it.

Constructors

UsageSite Module Int

DefinitionSite

Instances

Eq ConInfoTableLocation

Defined in GHC.Cmm.CLabel

Methods

(==) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

(/=) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

Ord ConInfoTableLocation

Defined in GHC.Cmm.CLabel

Methods

compare :: ConInfoTableLocation -> ConInfoTableLocation -> Ordering

(<) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

(<=) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

(>) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

(>=) :: ConInfoTableLocation -> ConInfoTableLocation -> Bool

max :: ConInfoTableLocation -> ConInfoTableLocation -> ConInfoTableLocation

min :: ConInfoTableLocation -> ConInfoTableLocation -> ConInfoTableLocation

Outputable ConInfoTableLocation

Defined in GHC.Cmm.CLabel

Methods

ppr :: ConInfoTableLocation -> SDoc

getConInfoTableLocation :: IdLabelInfo -> Maybe ConInfoTableLocation

Constructors

mkClosureLabel :: Name -> CafInfo -> CLabel

mkSRTLabel :: Unique -> CLabel

mkInfoTableLabel :: Name -> CafInfo -> CLabel

mkEntryLabel :: Name -> CafInfo -> CLabel

mkRednCountsLabel :: Name -> CLabel

mkConInfoTableLabel :: Name -> ConInfoTableLocation -> CLabel

mkApEntryLabel :: Platform -> Bool -> Int -> CLabel

mkApInfoTableLabel :: Platform -> Bool -> Int -> CLabel

mkClosureTableLabel :: Name -> CafInfo -> CLabel

mkBytesLabel :: Name -> CLabel

mkLocalBlockLabel :: Unique -> CLabel

mkLocalClosureLabel :: Name -> CafInfo -> CLabel

mkLocalInfoTableLabel :: Name -> CafInfo -> CLabel

mkLocalClosureTableLabel :: Name -> CafInfo -> CLabel

mkBlockInfoTableLabel :: Name -> CafInfo -> CLabel

mkBitmapLabel :: Unique -> CLabel

mkStringLitLabel :: Unique -> CLabel

mkAsmTempLabel :: Uniquable a => a -> CLabel

mkAsmTempDerivedLabel :: CLabel -> FastString -> CLabel

mkAsmTempEndLabel :: CLabel -> CLabel

mkAsmTempProcEndLabel :: CLabel -> CLabel

A label indicating the end of a procedure.

mkAsmTempDieLabel :: CLabel -> CLabel

Construct a label for a DWARF Debug Information Entity (DIE) describing another symbol.

mkDirty_MUT_VAR_Label :: CLabel

mkMUT_VAR_CLEAN_infoLabel :: CLabel

mkNonmovingWriteBarrierEnabledLabel :: CLabel

mkUpdInfoLabel :: CLabel

mkBHUpdInfoLabel :: CLabel

mkIndStaticInfoLabel :: CLabel

mkMainCapabilityLabel :: CLabel

mkMAP_FROZEN_CLEAN_infoLabel :: CLabel

mkMAP_FROZEN_DIRTY_infoLabel :: CLabel

mkMAP_DIRTY_infoLabel :: CLabel

mkSMAP_FROZEN_CLEAN_infoLabel :: CLabel

mkSMAP_FROZEN_DIRTY_infoLabel :: CLabel

mkSMAP_DIRTY_infoLabel :: CLabel

mkBadAlignmentLabel :: CLabel

mkOutOfBoundsAccessLabel :: CLabel

mkArrWords_infoLabel :: CLabel

mkSRTInfoLabel :: Int -> CLabel

mkTopTickyCtrLabel :: CLabel

mkCAFBlackHoleInfoTableLabel :: CLabel

mkRtsPrimOpLabel :: PrimOp -> CLabel

mkRtsSlowFastTickyCtrLabel :: String -> CLabel

mkSelectorInfoLabel :: Platform -> Bool -> Int -> CLabel

mkSelectorEntryLabel :: Platform -> Bool -> Int -> CLabel

mkCmmInfoLabel :: UnitId -> FastString -> CLabel

mkCmmEntryLabel :: UnitId -> FastString -> CLabel

mkCmmRetInfoLabel :: UnitId -> FastString -> CLabel

mkCmmRetLabel :: UnitId -> FastString -> CLabel

mkCmmCodeLabel :: UnitId -> FastString -> CLabel

mkCmmDataLabel :: UnitId -> NeedExternDecl -> FastString -> CLabel

mkRtsCmmDataLabel :: FastString -> CLabel

mkCmmClosureLabel :: UnitId -> FastString -> CLabel

mkRtsApFastLabel :: FastString -> CLabel

mkPrimCallLabel :: PrimCall -> CLabel

mkForeignLabel :: FastString -> Maybe Int -> ForeignLabelSource -> FunctionOrData -> CLabel

Make a foreign label

mkCCLabel :: CostCentre -> CLabel

mkCCSLabel :: CostCentreStack -> CLabel

mkIPELabel :: InfoProvEnt -> CLabel

data InfoProvEnt

Info Table Provenance Entry See Note [Mapping Info Tables to Source Positions]

Constructors

InfoProvEnt

Fields

• infoTablePtr :: !CLabel
• infoProvEntClosureType :: !Int
• infoTableType :: !String
• infoProvModule :: !Module
• infoTableProv :: !(Maybe (RealSrcSpan, String))

Instances

Eq InfoProvEnt

Defined in GHC.Cmm.CLabel

Methods

(==) :: InfoProvEnt -> InfoProvEnt -> Bool

(/=) :: InfoProvEnt -> InfoProvEnt -> Bool

Ord InfoProvEnt

Defined in GHC.Cmm.CLabel

Methods

compare :: InfoProvEnt -> InfoProvEnt -> Ordering

(<) :: InfoProvEnt -> InfoProvEnt -> Bool

(<=) :: InfoProvEnt -> InfoProvEnt -> Bool

(>) :: InfoProvEnt -> InfoProvEnt -> Bool

(>=) :: InfoProvEnt -> InfoProvEnt -> Bool

max :: InfoProvEnt -> InfoProvEnt -> InfoProvEnt

min :: InfoProvEnt -> InfoProvEnt -> InfoProvEnt

mkDynamicLinkerLabel :: DynamicLinkerLabelInfo -> CLabel -> CLabel

mkPicBaseLabel :: CLabel

mkDeadStripPreventer :: CLabel -> CLabel

mkHpcTicksLabel :: Module -> CLabel

Predicates

hasCAF :: CLabel -> Bool

needsCDecl :: CLabel -> Bool

maybeLocalBlockLabel :: CLabel -> Maybe BlockId

If a label is a local block label then return just its BlockId, otherwise Nothing.

externallyVisibleCLabel :: CLabel -> Bool

Is a CLabel visible outside this object file or not? From the point of view of the code generator, a name is externally visible if it has to be declared as exported in the .o file's symbol table; that is, made non-static.

isMathFun :: CLabel -> Bool

Check whether a label corresponds to a C function that has a prototype in a system header somewhere, or is built-in to the C compiler. For these labels we avoid generating our own C prototypes.

isCFunctionLabel :: CLabel -> Bool

isGcPtrLabel :: CLabel -> Bool

labelDynamic :: Module -> Platform -> Bool -> CLabel -> Bool

Does a CLabel need dynamic linkage?

When referring to data in code, we need to know whether that data resides in a DLL or not. [Win32 only.] labelDynamic returns True if the label is located in a DLL, be it a data reference or not.

isLocalCLabel :: Module -> CLabel -> Bool

Is a CLabel defined in the current module being compiled?

Sometimes we can optimise references within a compilation unit in ways that we couldn't for inter-module references. This provides a conservative estimate of whether a CLabel lives in the current module.

mayRedirectTo :: CLabel -> CLabel -> Bool

isInfoTableLabel :: CLabel -> Bool

Whether label is points to some kind of info table

isConInfoTableLabel :: CLabel -> Bool

Whether label is points to constructor info table

isIdLabel :: CLabel -> Bool

isTickyLabel :: CLabel -> Bool

hasHaskellName :: CLabel -> Maybe Name

hasIdLabelInfo :: CLabel -> Maybe IdLabelInfo

isBytesLabel :: CLabel -> Bool

Whether label is a top-level string literal

isForeignLabel :: CLabel -> Bool

Whether label is a non-haskell label (defined in C code)

isSomeRODataLabel :: CLabel -> Bool

Whether label is a .rodata label

isStaticClosureLabel :: CLabel -> Bool

Whether label is a static closure label (can come from haskell or cmm)

Conversions

toClosureLbl :: Platform -> CLabel -> CLabel

toSlowEntryLbl :: Platform -> CLabel -> CLabel

toEntryLbl :: Platform -> CLabel -> CLabel

toInfoLbl :: Platform -> CLabel -> CLabel

Pretty-printing

data LabelStyle

Style of label pretty-printing.

When we produce C sources or headers, we have to take into account that C compilers transform C labels when they convert them into symbols. For example, they can add prefixes (e.g., "_" on Darwin) or suffixes (size for stdcalls on Windows). So we provide two ways to pretty-print CLabels: C style or Asm style.

Constructors

CStyle

C label style (used by C and LLVM backends)

AsmStyle

Asm label style (used by NCG backend)

Instances

Eq LabelStyle

Defined in GHC.Utils.Outputable

Methods

(==) :: LabelStyle -> LabelStyle -> Bool

(/=) :: LabelStyle -> LabelStyle -> Bool

Ord LabelStyle

Defined in GHC.Utils.Outputable

Methods

compare :: LabelStyle -> LabelStyle -> Ordering

(<) :: LabelStyle -> LabelStyle -> Bool

(<=) :: LabelStyle -> LabelStyle -> Bool

(>) :: LabelStyle -> LabelStyle -> Bool

(>=) :: LabelStyle -> LabelStyle -> Bool

max :: LabelStyle -> LabelStyle -> LabelStyle

min :: LabelStyle -> LabelStyle -> LabelStyle

Show LabelStyle

Defined in GHC.Utils.Outputable

Methods

showsPrec :: Int -> LabelStyle -> ShowS

show :: LabelStyle -> String

showList :: [LabelStyle] -> ShowS

pprDebugCLabel :: Platform -> CLabel -> SDoc

For debugging problems with the CLabel representation. We can't make a Show instance for CLabel because lots of its components don't have instances. The regular Outputable instance only shows the label name, and not its other info.

pprCLabel :: Platform -> LabelStyle -> CLabel -> SDoc

ppInternalProcLabel

Arguments

:: Module

the current module

-> CLabel

-> Maybe SDoc

the internal proc label

Generate a label for a procedure internal to a module (if Opt_ExposeAllSymbols is enabled). See Note [Internal proc labels].

Others

dynamicLinkerLabelInfo :: CLabel -> Maybe (DynamicLinkerLabelInfo, CLabel)

addLabelSize :: CLabel -> Int -> CLabel

Update the label size field in a ForeignLabel

foreignLabelStdcallInfo :: CLabel -> Maybe Int

Get the label size field from a ForeignLabel