-- ----------------------------------------------------------------------------- -- -- (c) The University of Glasgow 1993-2004 -- -- -- ----------------------------------------------------------------------------- {-# LANGUAGE BangPatterns #-} {-# LANGUAGE DeriveFunctor #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE PatternSynonyms #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE UnboxedTuples #-} -- | Native code generator -- -- The native-code generator has machine-independent and -- machine-dependent modules. -- -- This module ("GHC.CmmToAsm") is the top-level machine-independent -- module. Before entering machine-dependent land, we do some -- machine-independent optimisations (defined below) on the -- 'CmmStmts's. -- -- We convert to the machine-specific 'Instr' datatype with -- 'cmmCodeGen', assuming an infinite supply of registers. We then use -- a machine-independent register allocator ('regAlloc') to rejoin -- reality. Obviously, 'regAlloc' has machine-specific helper -- functions (see about "RegAllocInfo" below). -- -- Finally, we order the basic blocks of the function so as to minimise -- the number of jumps between blocks, by utilising fallthrough wherever -- possible. -- -- The machine-dependent bits break down as follows: -- -- * ["MachRegs"] Everything about the target platform's machine -- registers (and immediate operands, and addresses, which tend to -- intermingle/interact with registers). -- -- * ["MachInstrs"] Includes the 'Instr' datatype (possibly should -- have a module of its own), plus a miscellany of other things -- (e.g., 'targetDoubleSize', 'smStablePtrTable', ...) -- -- * ["MachCodeGen"] is where 'Cmm' stuff turns into -- machine instructions. -- -- * ["PprMach"] 'pprInstr' turns an 'Instr' into text (well, really -- a 'SDoc'). -- -- * ["RegAllocInfo"] In the register allocator, we manipulate -- 'MRegsState's, which are 'BitSet's, one bit per machine register. -- When we want to say something about a specific machine register -- (e.g., ``it gets clobbered by this instruction''), we set/unset -- its bit. Obviously, we do this 'BitSet' thing for efficiency -- reasons. -- -- The 'RegAllocInfo' module collects together the machine-specific -- info needed to do register allocation. -- -- * ["RegisterAlloc"] The (machine-independent) register allocator. -- -} -- module GHC.CmmToAsm ( nativeCodeGen -- * Test-only exports: see trac #12744 -- used by testGraphNoSpills, which needs to access -- the register allocator intermediate data structures -- cmmNativeGen emits , cmmNativeGen , NcgImpl(..) ) where import GHC.Prelude hiding (head) import qualified GHC.CmmToAsm.X86 as X86 import qualified GHC.CmmToAsm.PPC as PPC import qualified GHC.CmmToAsm.AArch64 as AArch64 import qualified GHC.CmmToAsm.Wasm as Wasm32 import GHC.CmmToAsm.Reg.Liveness import qualified GHC.CmmToAsm.Reg.Linear as Linear import qualified GHC.Data.Graph.Color as Color import qualified GHC.CmmToAsm.Reg.Graph as Color import qualified GHC.CmmToAsm.Reg.Graph.Stats as Color import qualified GHC.CmmToAsm.Reg.Graph.TrivColorable as Color import GHC.Utils.Asm import GHC.CmmToAsm.Reg.Target import GHC.Platform import GHC.CmmToAsm.BlockLayout as BlockLayout import GHC.Settings.Config import GHC.CmmToAsm.Instr import GHC.CmmToAsm.PIC import GHC.Platform.Reg import GHC.Platform.Reg.Class (RegClass) import GHC.CmmToAsm.Monad import GHC.CmmToAsm.CFG import GHC.CmmToAsm.Dwarf import GHC.CmmToAsm.Config import GHC.CmmToAsm.Types import GHC.Cmm.DebugBlock import GHC.Cmm.BlockId import GHC.StgToCmm.CgUtils ( fixStgRegisters ) import GHC.Cmm import GHC.Cmm.Utils import GHC.Cmm.Dataflow.Collections import GHC.Cmm.Dataflow.Label import GHC.Cmm.Dataflow.Block import GHC.Cmm.Opt ( cmmMachOpFold ) import GHC.Cmm.CLabel import GHC.Types.Unique.FM import GHC.Types.Unique.Supply import GHC.Driver.Session import GHC.Driver.Ppr import GHC.Utils.Misc import GHC.Utils.Logger import GHC.Utils.BufHandle import GHC.Utils.Outputable as Outputable import GHC.Utils.Panic import GHC.Utils.Error import GHC.Utils.Exception (evaluate) import GHC.Utils.Constants (debugIsOn) import GHC.Data.FastString import GHC.Types.Unique.Set import GHC.Unit import GHC.Data.Stream (Stream) import qualified GHC.Data.Stream as Stream import Data.List (sortBy) import Data.List.NonEmpty (groupAllWith, head) import Data.Maybe import Data.Ord ( comparing ) import Control.Monad import System.IO import System.Directory ( getCurrentDirectory ) -------------------- nativeCodeGen :: forall a . Logger -> NCGConfig -> ModLocation -> Handle -> UniqSupply -> Stream IO RawCmmGroup a -> IO a nativeCodeGen logger config modLoc h us cmms = let platform = ncgPlatform config nCG' :: ( OutputableP Platform statics, Outputable jumpDest, Instruction instr) => NcgImpl statics instr jumpDest -> IO a nCG' ncgImpl = nativeCodeGen' logger config modLoc ncgImpl h us cmms in case platformArch platform of ArchX86 -> nCG' (X86.ncgX86 config) ArchX86_64 -> nCG' (X86.ncgX86_64 config) ArchPPC -> nCG' (PPC.ncgPPC config) ArchPPC_64 _ -> nCG' (PPC.ncgPPC config) ArchS390X -> panic "nativeCodeGen: No NCG for S390X" ArchARM {} -> panic "nativeCodeGen: No NCG for ARM" ArchAArch64 -> nCG' (AArch64.ncgAArch64 config) ArchAlpha -> panic "nativeCodeGen: No NCG for Alpha" ArchMipseb -> panic "nativeCodeGen: No NCG for mipseb" ArchMipsel -> panic "nativeCodeGen: No NCG for mipsel" ArchRISCV64 -> panic "nativeCodeGen: No NCG for RISCV64" ArchLoongArch64->panic "nativeCodeGen: No NCG for LoongArch64" ArchUnknown -> panic "nativeCodeGen: No NCG for unknown arch" ArchJavaScript-> panic "nativeCodeGen: No NCG for JavaScript" ArchWasm32 -> Wasm32.ncgWasm platform us modLoc h cmms -- | Data accumulated during code generation. Mostly about statistics, -- but also collects debug data for DWARF generation. data NativeGenAcc statics instr = NGS { ngs_imports :: ![[CLabel]] , ngs_natives :: ![[NatCmmDecl statics instr]] -- ^ Native code generated, for statistics. This might -- hold a lot of data, so it is important to clear this -- field as early as possible if it isn't actually -- required. , ngs_colorStats :: ![[Color.RegAllocStats statics instr]] , ngs_linearStats :: ![[Linear.RegAllocStats]] , ngs_labels :: ![Label] , ngs_debug :: ![DebugBlock] , ngs_dwarfFiles :: !DwarfFiles , ngs_unwinds :: !(LabelMap [UnwindPoint]) -- ^ see Note [Unwinding information in the NCG] -- and Note [What is this unwinding business?] in "GHC.Cmm.DebugBlock". } {- Note [Unwinding information in the NCG] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Unwind information is a type of metadata which allows a debugging tool to reconstruct the values of machine registers at the time a procedure was entered. For the most part, the production of unwind information is handled by the Cmm stage, where it is represented by CmmUnwind nodes. Unfortunately, the Cmm stage doesn't know everything necessary to produce accurate unwinding information. For instance, the x86-64 calling convention requires that the stack pointer be aligned to 16 bytes, which in turn means that GHC must sometimes add padding to $sp prior to performing a foreign call. When this happens unwind information must be updated accordingly. For this reason, we make the NCG backends responsible for producing unwinding tables (with the extractUnwindPoints function in NcgImpl). We accumulate the produced unwind tables over CmmGroups in the ngs_unwinds field of NativeGenAcc. This is a label map which contains an entry for each procedure, containing a list of unwinding points (e.g. a label and an associated unwinding table). See also Note [What is this unwinding business?] in "GHC.Cmm.DebugBlock". -} nativeCodeGen' :: (OutputableP Platform statics, Outputable jumpDest, Instruction instr) => Logger -> NCGConfig -> ModLocation -> NcgImpl statics instr jumpDest -> Handle -> UniqSupply -> Stream IO RawCmmGroup a -> IO a nativeCodeGen' logger config modLoc ncgImpl h us cmms = do -- BufHandle is a performance hack. We could hide it inside -- Pretty if it weren't for the fact that we do lots of little -- printDocs here (in order to do codegen in constant space). bufh <- newBufHandle h let ngs0 = NGS [] [] [] [] [] [] emptyUFM mapEmpty (ngs, us', a) <- cmmNativeGenStream logger config modLoc ncgImpl bufh us cmms ngs0 _ <- finishNativeGen logger config modLoc bufh us' ngs return a finishNativeGen :: Instruction instr => Logger -> NCGConfig -> ModLocation -> BufHandle -> UniqSupply -> NativeGenAcc statics instr -> IO UniqSupply finishNativeGen logger config modLoc bufh us ngs = withTimingSilent logger (text "NCG") (`seq` ()) $ do -- Write debug data and finish us' <- if not (ncgDwarfEnabled config) then return us else do compPath <- getCurrentDirectory let (dwarf_h, us') = dwarfGen compPath config modLoc us (ngs_debug ngs) (dwarf_s, _) = dwarfGen compPath config modLoc us (ngs_debug ngs) emitNativeCode logger config bufh dwarf_h dwarf_s return us' -- dump global NCG stats for graph coloring allocator let stats = concat (ngs_colorStats ngs) unless (null stats) $ do -- build the global register conflict graph let graphGlobal = foldl' Color.union Color.initGraph $ [ Color.raGraph stat | stat@Color.RegAllocStatsStart{} <- stats] dump_stats (Color.pprStats stats graphGlobal) let platform = ncgPlatform config putDumpFileMaybe logger Opt_D_dump_asm_conflicts "Register conflict graph" FormatText $ Color.dotGraph (targetRegDotColor platform) (Color.trivColorable platform (targetVirtualRegSqueeze platform) (targetRealRegSqueeze platform)) $ graphGlobal -- dump global NCG stats for linear allocator let linearStats = concat (ngs_linearStats ngs) unless (null linearStats) $ dump_stats (Linear.pprStats (concat (ngs_natives ngs)) linearStats) -- write out the imports let ctx = ncgAsmContext config bPutHDoc bufh ctx $ makeImportsDoc config (concat (ngs_imports ngs)) bFlush bufh return us' where dump_stats = logDumpFile logger (mkDumpStyle alwaysQualify) Opt_D_dump_asm_stats "NCG stats" FormatText cmmNativeGenStream :: forall statics jumpDest instr a . (OutputableP Platform statics, Outputable jumpDest, Instruction instr) => Logger -> NCGConfig -> ModLocation -> NcgImpl statics instr jumpDest -> BufHandle -> UniqSupply -> Stream.Stream IO RawCmmGroup a -> NativeGenAcc statics instr -> IO (NativeGenAcc statics instr, UniqSupply, a) cmmNativeGenStream logger config modLoc ncgImpl h us cmm_stream ngs = loop us (Stream.runStream cmm_stream) ngs where ncglabel = text "NCG" loop :: UniqSupply -> Stream.StreamS IO RawCmmGroup a -> NativeGenAcc statics instr -> IO (NativeGenAcc statics instr, UniqSupply, a) loop us s ngs = case s of Stream.Done a -> return (ngs { ngs_imports = reverse $ ngs_imports ngs , ngs_natives = reverse $ ngs_natives ngs , ngs_colorStats = reverse $ ngs_colorStats ngs , ngs_linearStats = reverse $ ngs_linearStats ngs }, us, a) Stream.Effect m -> m >>= \cmm_stream' -> loop us cmm_stream' ngs Stream.Yield cmms cmm_stream' -> do (us', ngs'') <- withTimingSilent logger ncglabel (\(a, b) -> a `seq` b `seq` ()) $ do -- Generate debug information let !ndbgs | ncgDwarfEnabled config = cmmDebugGen modLoc cmms | otherwise = [] dbgMap = debugToMap ndbgs -- Generate native code (ngs',us') <- cmmNativeGens logger config ncgImpl h dbgMap us cmms ngs 0 -- Link native code information into debug blocks -- See Note [What is this unwinding business?] in "GHC.Cmm.DebugBlock". let !ldbgs = cmmDebugLink (ngs_labels ngs') (ngs_unwinds ngs') ndbgs platform = ncgPlatform config unless (null ldbgs) $ putDumpFileMaybe logger Opt_D_dump_debug "Debug Infos" FormatText (vcat $ map (pdoc platform) ldbgs) -- Accumulate debug information for emission in finishNativeGen. let ngs'' = ngs' { ngs_debug = ngs_debug ngs' ++ ldbgs, ngs_labels = [] } return (us', ngs'') loop us' cmm_stream' ngs'' -- | Do native code generation on all these cmms. -- cmmNativeGens :: forall statics instr jumpDest. (OutputableP Platform statics, Outputable jumpDest, Instruction instr) => Logger -> NCGConfig -> NcgImpl statics instr jumpDest -> BufHandle -> LabelMap DebugBlock -> UniqSupply -> [RawCmmDecl] -> NativeGenAcc statics instr -> Int -> IO (NativeGenAcc statics instr, UniqSupply) cmmNativeGens logger config ncgImpl h dbgMap = go where go :: UniqSupply -> [RawCmmDecl] -> NativeGenAcc statics instr -> Int -> IO (NativeGenAcc statics instr, UniqSupply) go us [] ngs !_ = return (ngs, us) go us (cmm : cmms) ngs count = do let fileIds = ngs_dwarfFiles ngs (us', fileIds', native, imports, colorStats, linearStats, unwinds) <- {-# SCC "cmmNativeGen" #-} cmmNativeGen logger ncgImpl us fileIds dbgMap cmm count -- Generate .file directives for every new file that has been -- used. Note that it is important that we generate these in -- ascending order, as Clang's 3.6 assembler complains. let newFileIds = sortBy (comparing snd) $ nonDetEltsUFM $ fileIds' `minusUFM` fileIds -- See Note [Unique Determinism and code generation] pprDecl (f,n) = line $ text "\t.file " <> int n <+> pprFilePathString (unpackFS f) -- see Note [pprNatCmmDeclS and pprNatCmmDeclH] in GHC.CmmToAsm.Monad emitNativeCode logger config h (vcat $ map pprDecl newFileIds ++ map (pprNatCmmDeclH ncgImpl) native) (vcat $ map pprDecl newFileIds ++ map (pprNatCmmDeclS ncgImpl) native) -- force evaluation all this stuff to avoid space leaks let platform = ncgPlatform config {-# SCC "seqString" #-} evaluate $ seqList (showSDocUnsafe $ vcat $ map (pprAsmLabel platform) imports) () let !labels' = if ncgDwarfEnabled config then cmmDebugLabels isMetaInstr native else [] !natives' = if logHasDumpFlag logger Opt_D_dump_asm_stats then native : ngs_natives ngs else [] mCon = maybe id (:) ngs' = ngs{ ngs_imports = imports : ngs_imports ngs , ngs_natives = natives' , ngs_colorStats = colorStats `mCon` ngs_colorStats ngs , ngs_linearStats = linearStats `mCon` ngs_linearStats ngs , ngs_labels = ngs_labels ngs ++ labels' , ngs_dwarfFiles = fileIds' , ngs_unwinds = ngs_unwinds ngs `mapUnion` unwinds } go us' cmms ngs' (count + 1) -- see Note [pprNatCmmDeclS and pprNatCmmDeclH] in GHC.CmmToAsm.Monad emitNativeCode :: Logger -> NCGConfig -> BufHandle -> HDoc -> SDoc -> IO () emitNativeCode logger config h hdoc sdoc = do let ctx = ncgAsmContext config {-# SCC "pprNativeCode" #-} bPutHDoc h ctx hdoc -- dump native code putDumpFileMaybe logger Opt_D_dump_asm "Asm code" FormatASM sdoc -- | Complete native code generation phase for a single top-level chunk of Cmm. -- Dumping the output of each stage along the way. -- Global conflict graph and NGC stats cmmNativeGen :: forall statics instr jumpDest. (Instruction instr, OutputableP Platform statics, Outputable jumpDest) => Logger -> NcgImpl statics instr jumpDest -> UniqSupply -> DwarfFiles -> LabelMap DebugBlock -> RawCmmDecl -- ^ the cmm to generate code for -> Int -- ^ sequence number of this top thing -> IO ( UniqSupply , DwarfFiles , [NatCmmDecl statics instr] -- native code , [CLabel] -- things imported by this cmm , Maybe [Color.RegAllocStats statics instr] -- stats for the coloring register allocator , Maybe [Linear.RegAllocStats] -- stats for the linear register allocators , LabelMap [UnwindPoint] -- unwinding information for blocks ) cmmNativeGen logger ncgImpl us fileIds dbgMap cmm count = do let config = ncgConfig ncgImpl let platform = ncgPlatform config let weights = ncgCfgWeights config let proc_name = case cmm of (CmmProc _ entry_label _ _) -> pprAsmLabel platform entry_label _ -> text "DataChunk" -- rewrite assignments to global regs let fixed_cmm = {-# SCC "fixStgRegisters" #-} fixStgRegisters platform cmm -- cmm to cmm optimisations let (opt_cmm, imports) = {-# SCC "cmmToCmm" #-} cmmToCmm config fixed_cmm putDumpFileMaybe logger Opt_D_dump_opt_cmm "Optimised Cmm" FormatCMM (pprCmmGroup platform [opt_cmm]) let cmmCfg = {-# SCC "getCFG" #-} getCfgProc platform weights opt_cmm -- generate native code from cmm let ((native, lastMinuteImports, fileIds', nativeCfgWeights), usGen) = {-# SCC "genMachCode" #-} initUs us $ genMachCode config (cmmTopCodeGen ncgImpl) fileIds dbgMap opt_cmm cmmCfg putDumpFileMaybe logger Opt_D_dump_asm_native "Native code" FormatASM (vcat $ map (pprNatCmmDeclS ncgImpl) native) maybeDumpCfg logger (Just nativeCfgWeights) "CFG Weights - Native" proc_name -- tag instructions with register liveness information -- also drops dead code. We don't keep the cfg in sync on -- some backends, so don't use it there. let livenessCfg = if ncgEnableDeadCodeElimination config then Just nativeCfgWeights else Nothing let (withLiveness, usLive) = {-# SCC "regLiveness" #-} initUs usGen $ mapM (cmmTopLiveness livenessCfg platform) native putDumpFileMaybe logger Opt_D_dump_asm_liveness "Liveness annotations added" FormatCMM (vcat $ map (pprLiveCmmDecl platform) withLiveness) -- allocate registers (alloced, usAlloc, ppr_raStatsColor, ppr_raStatsLinear, raStats, stack_updt_blks) <- if ( ncgRegsGraph config || ncgRegsIterative config ) then do -- the regs usable for allocation let (alloc_regs :: UniqFM RegClass (UniqSet RealReg)) = foldr (\r -> plusUFM_C unionUniqSets $ unitUFM (targetClassOfRealReg platform r) (unitUniqSet r)) emptyUFM $ allocatableRegs ncgImpl -- do the graph coloring register allocation let ((alloced, maybe_more_stack, regAllocStats), usAlloc) = {-# SCC "RegAlloc-color" #-} initUs usLive $ Color.regAlloc config alloc_regs (mkUniqSet [0 .. maxSpillSlots ncgImpl]) (maxSpillSlots ncgImpl) withLiveness livenessCfg let ((alloced', stack_updt_blks), usAlloc') = initUs usAlloc $ case maybe_more_stack of Nothing -> return (alloced, []) Just amount -> do (alloced',stack_updt_blks) <- unzip <$> (mapM ((ncgAllocMoreStack ncgImpl) amount) alloced) return (alloced', concat stack_updt_blks ) -- dump out what happened during register allocation putDumpFileMaybe logger Opt_D_dump_asm_regalloc "Registers allocated" FormatCMM (vcat $ map (pprNatCmmDeclS ncgImpl) alloced) putDumpFileMaybe logger Opt_D_dump_asm_regalloc_stages "Build/spill stages" FormatText (vcat $ map (\(stage, stats) -> text "# --------------------------" $$ text "# cmm " <> int count <> text " Stage " <> int stage $$ ppr (fmap (pprInstr platform) stats)) $ zip [0..] regAllocStats) let mPprStats = if logHasDumpFlag logger Opt_D_dump_asm_stats then Just regAllocStats else Nothing -- force evaluation of the Maybe to avoid space leak mPprStats `seq` return () return ( alloced', usAlloc' , mPprStats , Nothing , [], stack_updt_blks) else do -- do linear register allocation let reg_alloc proc = do (alloced, maybe_more_stack, ra_stats) <- Linear.regAlloc config proc case maybe_more_stack of Nothing -> return ( alloced, ra_stats, [] ) Just amount -> do (alloced',stack_updt_blks) <- ncgAllocMoreStack ncgImpl amount alloced return (alloced', ra_stats, stack_updt_blks ) let ((alloced, regAllocStats, stack_updt_blks), usAlloc) = {-# SCC "RegAlloc-linear" #-} initUs usLive $ liftM unzip3 $ mapM reg_alloc withLiveness putDumpFileMaybe logger Opt_D_dump_asm_regalloc "Registers allocated" FormatCMM (vcat $ map (pprNatCmmDeclS ncgImpl) alloced) let mPprStats = if logHasDumpFlag logger Opt_D_dump_asm_stats then Just (catMaybes regAllocStats) else Nothing -- force evaluation of the Maybe to avoid space leak mPprStats `seq` return () return ( alloced, usAlloc , Nothing , mPprStats, (catMaybes regAllocStats) , concat stack_updt_blks ) -- Fixupblocks the register allocator inserted (from, regMoves, to) let cfgRegAllocUpdates :: [(BlockId,BlockId,BlockId)] cfgRegAllocUpdates = (concatMap Linear.ra_fixupList raStats) let cfgWithFixupBlks = (\cfg -> addNodesBetween weights cfg cfgRegAllocUpdates) <$> livenessCfg -- Insert stack update blocks let postRegCFG = pure (foldl' (\m (from,to) -> addImmediateSuccessor weights from to m )) <*> cfgWithFixupBlks <*> pure stack_updt_blks ---- generate jump tables let tabled = {-# SCC "generateJumpTables" #-} generateJumpTables ncgImpl alloced when (not $ null nativeCfgWeights) $ putDumpFileMaybe logger Opt_D_dump_cfg_weights "CFG Update information" FormatText ( text "stack:" <+> ppr stack_updt_blks $$ text "linearAlloc:" <+> ppr cfgRegAllocUpdates ) ---- shortcut branches let (shorted, postShortCFG) = {-# SCC "shortcutBranches" #-} shortcutBranches config ncgImpl tabled postRegCFG let optimizedCFG :: Maybe CFG optimizedCFG = optimizeCFG (ncgCmmStaticPred config) weights cmm <$!> postShortCFG maybeDumpCfg logger optimizedCFG "CFG Weights - Final" proc_name --TODO: Partially check validity of the cfg. let getBlks (CmmProc _info _lbl _live (ListGraph blocks)) = blocks getBlks _ = [] when ( ncgEnableDeadCodeElimination config && (ncgAsmLinting config || debugIsOn )) $ do let blocks = concatMap getBlks shorted let labels = setFromList $ fmap blockId blocks :: LabelSet let cfg = fromJust optimizedCFG return $! seq (sanityCheckCfg cfg labels $ text "cfg not in lockstep") () ---- sequence blocks let sequenced :: [NatCmmDecl statics instr] sequenced = checkLayout shorted $ {-# SCC "sequenceBlocks" #-} map (BlockLayout.sequenceTop ncgImpl optimizedCFG) shorted let branchOpt :: [NatCmmDecl statics instr] branchOpt = {-# SCC "invertCondBranches" #-} map invert sequenced where invertConds :: LabelMap RawCmmStatics -> [NatBasicBlock instr] -> [NatBasicBlock instr] invertConds = invertCondBranches ncgImpl optimizedCFG invert top@CmmData {} = top invert (CmmProc info lbl live (ListGraph blocks)) = CmmProc info lbl live (ListGraph $ invertConds info blocks) -- generate unwinding information from cmm let unwinds :: BlockMap [UnwindPoint] unwinds = {-# SCC "unwindingInfo" #-} foldl' addUnwind mapEmpty branchOpt where addUnwind acc proc = acc `mapUnion` computeUnwinding config ncgImpl proc return ( usAlloc , fileIds' , branchOpt , lastMinuteImports ++ imports , ppr_raStatsColor , ppr_raStatsLinear , unwinds ) maybeDumpCfg :: Logger -> Maybe CFG -> String -> SDoc -> IO () maybeDumpCfg _logger Nothing _ _ = return () maybeDumpCfg logger (Just cfg) msg proc_name | null cfg = return () | otherwise = putDumpFileMaybe logger Opt_D_dump_cfg_weights msg FormatText (proc_name <> char ':' $$ pprEdgeWeights cfg) -- | Make sure all blocks we want the layout algorithm to place have been placed. checkLayout :: [NatCmmDecl statics instr] -> [NatCmmDecl statics instr] -> [NatCmmDecl statics instr] checkLayout procsUnsequenced procsSequenced = assertPpr (setNull diff) (text "Block sequencing dropped blocks:" <> ppr diff) procsSequenced where blocks1 = foldl' (setUnion) setEmpty $ map getBlockIds procsUnsequenced :: LabelSet blocks2 = foldl' (setUnion) setEmpty $ map getBlockIds procsSequenced diff = setDifference blocks1 blocks2 getBlockIds (CmmData _ _) = setEmpty getBlockIds (CmmProc _ _ _ (ListGraph blocks)) = setFromList $ map blockId blocks -- | Compute unwinding tables for the blocks of a procedure computeUnwinding :: Instruction instr => NCGConfig -> NcgImpl statics instr jumpDest -> NatCmmDecl statics instr -- ^ the native code generated for the procedure -> LabelMap [UnwindPoint] -- ^ unwinding tables for all points of all blocks of the -- procedure computeUnwinding config _ _ | not (ncgComputeUnwinding config) = mapEmpty computeUnwinding _ _ (CmmData _ _) = mapEmpty computeUnwinding _ ncgImpl (CmmProc _ _ _ (ListGraph blks)) = -- In general we would need to push unwinding information down the -- block-level call-graph to ensure that we fully account for all -- relevant register writes within a procedure. -- -- However, the only unwinding information that we care about in GHC is for -- Sp. The fact that GHC.Cmm.LayoutStack already ensures that we have unwind -- information at the beginning of every block means that there is no need -- to perform this sort of push-down. mapFromList [ (blk_lbl, extractUnwindPoints ncgImpl instrs) | BasicBlock blk_lbl instrs <- blks ] -- | Build a doc for all the imports. -- makeImportsDoc :: NCGConfig -> [CLabel] -> HDoc makeImportsDoc config imports = dyld_stubs imports $$ -- On recent versions of Darwin, the linker supports -- dead-stripping of code and data on a per-symbol basis. -- There's a hack to make this work in PprMach.pprNatCmmDecl. (if platformHasSubsectionsViaSymbols platform then line $ text ".subsections_via_symbols" else Outputable.empty) $$ -- On recent GNU ELF systems one can mark an object file -- as not requiring an executable stack. If all objects -- linked into a program have this note then the program -- will not use an executable stack, which is good for -- security. GHC generated code does not need an executable -- stack so add the note in: (if platformHasGnuNonexecStack platform then line $ text ".section .note.GNU-stack,\"\"," <> sectionType platform "progbits" else Outputable.empty) $$ -- And just because every other compiler does, let's stick in -- an identifier directive: .ident "GHC x.y.z" (if platformHasIdentDirective platform then let compilerIdent = text "GHC" <+> text cProjectVersion in line $ text ".ident" <+> doubleQuotes compilerIdent else Outputable.empty) where platform = ncgPlatform config -- Generate "symbol stubs" for all external symbols that might -- come from a dynamic library. dyld_stubs :: [CLabel] -> HDoc -- (Hack) sometimes two Labels pretty-print the same, but have -- different uniques; so we compare their text versions... dyld_stubs imps | needImportedSymbols config = vcat $ (pprGotDeclaration config :) $ fmap (pprImportedSymbol config . fst . head) $ groupAllWith snd $ map doPpr $ imps | otherwise = Outputable.empty doPpr lbl = (lbl, showSDocOneLine (ncgAsmContext config) (pprAsmLabel platform lbl)) -- ----------------------------------------------------------------------------- -- Generate jump tables -- Analyzes all native code and generates data sections for all jump -- table instructions. generateJumpTables :: NcgImpl statics instr jumpDest -> [NatCmmDecl statics instr] -> [NatCmmDecl statics instr] generateJumpTables ncgImpl xs = concatMap f xs where f p@(CmmProc _ _ _ (ListGraph xs)) = p : concatMap g xs f p = [p] g (BasicBlock _ xs) = mapMaybe (generateJumpTableForInstr ncgImpl) xs -- ----------------------------------------------------------------------------- -- Shortcut branches shortcutBranches :: forall statics instr jumpDest. (Outputable jumpDest) => NCGConfig -> NcgImpl statics instr jumpDest -> [NatCmmDecl statics instr] -> Maybe CFG -> ([NatCmmDecl statics instr],Maybe CFG) shortcutBranches config ncgImpl tops weights | ncgEnableShortcutting config = ( map (apply_mapping ncgImpl mapping) tops' , shortcutWeightMap mappingBid <$!> weights ) | otherwise = (tops, weights) where (tops', mappings) = mapAndUnzip (build_mapping ncgImpl) tops mapping = mapUnions mappings :: LabelMap jumpDest mappingBid = fmap (getJumpDestBlockId ncgImpl) mapping build_mapping :: forall instr t d statics jumpDest. NcgImpl statics instr jumpDest -> GenCmmDecl d (LabelMap t) (ListGraph instr) -> (GenCmmDecl d (LabelMap t) (ListGraph instr) ,LabelMap jumpDest) build_mapping _ top@(CmmData _ _) = (top, mapEmpty) build_mapping _ (CmmProc info lbl live (ListGraph [])) = (CmmProc info lbl live (ListGraph []), mapEmpty) build_mapping ncgImpl (CmmProc info lbl live (ListGraph (head:blocks))) = (CmmProc info lbl live (ListGraph (head:others)), mapping) -- drop the shorted blocks, but don't ever drop the first one, -- because it is pointed to by a global label. where -- find all the blocks that just consist of a jump that can be -- shorted. -- Don't completely eliminate loops here -- that can leave a dangling jump! shortcut_blocks :: [(BlockId, jumpDest)] (_, shortcut_blocks, others) = foldl' split (setEmpty :: LabelSet, [], []) blocks split (s, shortcut_blocks, others) b@(BasicBlock id [insn]) | Just jd <- canShortcut ncgImpl insn , Just dest <- getJumpDestBlockId ncgImpl jd , not (has_info id) , (setMember dest s) || dest == id -- loop checks = (s, shortcut_blocks, b : others) split (s, shortcut_blocks, others) (BasicBlock id [insn]) | Just dest <- canShortcut ncgImpl insn , not (has_info id) = (setInsert id s, (id,dest) : shortcut_blocks, others) split (s, shortcut_blocks, others) other = (s, shortcut_blocks, other : others) -- do not eliminate blocks that have an info table has_info l = mapMember l info -- build a mapping from BlockId to JumpDest for shorting branches mapping = mapFromList shortcut_blocks apply_mapping :: NcgImpl statics instr jumpDest -> LabelMap jumpDest -> GenCmmDecl statics h (ListGraph instr) -> GenCmmDecl statics h (ListGraph instr) apply_mapping ncgImpl ufm (CmmData sec statics) = CmmData sec (shortcutStatics ncgImpl (\bid -> mapLookup bid ufm) statics) apply_mapping ncgImpl ufm (CmmProc info lbl live (ListGraph blocks)) = CmmProc info lbl live (ListGraph $ map short_bb blocks) where short_bb (BasicBlock id insns) = BasicBlock id $! map short_insn insns short_insn i = shortcutJump ncgImpl (\bid -> mapLookup bid ufm) i -- shortcutJump should apply the mapping repeatedly, -- just in case we can short multiple branches. -- ----------------------------------------------------------------------------- -- Instruction selection -- Native code instruction selection for a chunk of stix code. For -- this part of the computation, we switch from the UniqSM monad to -- the NatM monad. The latter carries not only a Unique, but also an -- Int denoting the current C stack pointer offset in the generated -- code; this is needed for creating correct spill offsets on -- architectures which don't offer, or for which it would be -- prohibitively expensive to employ, a frame pointer register. Viz, -- x86. -- The offset is measured in bytes, and indicates the difference -- between the current (simulated) C stack-ptr and the value it was at -- the beginning of the block. For stacks which grow down, this value -- should be either zero or negative. -- Along with the stack pointer offset, we also carry along a LabelMap of -- DebugBlocks, which we read to generate .location directives. -- -- Switching between the two monads whilst carrying along the same -- Unique supply breaks abstraction. Is that bad? genMachCode :: NCGConfig -> (RawCmmDecl -> NatM [NatCmmDecl statics instr]) -> DwarfFiles -> LabelMap DebugBlock -> RawCmmDecl -> CFG -> UniqSM ( [NatCmmDecl statics instr] , [CLabel] , DwarfFiles , CFG ) genMachCode config cmmTopCodeGen fileIds dbgMap cmm_top cmm_cfg = do { initial_us <- getUniqueSupplyM ; let initial_st = mkNatM_State initial_us 0 config fileIds dbgMap cmm_cfg (new_tops, final_st) = initNat initial_st (cmmTopCodeGen cmm_top) final_delta = natm_delta final_st final_imports = natm_imports final_st final_cfg = natm_cfg final_st ; if final_delta == 0 then return (new_tops, final_imports , natm_fileid final_st, final_cfg) else pprPanic "genMachCode: nonzero final delta" (int final_delta) } -- ----------------------------------------------------------------------------- -- Generic Cmm optimiser {- Here we do: (a) Constant folding (c) Position independent code and dynamic linking (i) introduce the appropriate indirections and position independent refs (ii) compile a list of imported symbols (d) Some arch-specific optimizations (a) will be moving to the new Hoopl pipeline, however, (c) and (d) are only needed by the native backend and will continue to live here. Ideas for other things we could do (put these in Hoopl please!): - shortcut jumps-to-jumps - simple CSE: if an expr is assigned to a temp, then replace later occs of that expr with the temp, until the expr is no longer valid (can push through temp assignments, and certain assigns to mem...) -} cmmToCmm :: NCGConfig -> RawCmmDecl -> (RawCmmDecl, [CLabel]) cmmToCmm _ top@(CmmData _ _) = (top, []) cmmToCmm config (CmmProc info lbl live graph) = runCmmOpt config $ do blocks' <- mapM cmmBlockConFold (toBlockList graph) return $ CmmProc info lbl live (ofBlockList (g_entry graph) blocks') type OptMResult a = (# a, [CLabel] #) pattern OptMResult :: a -> b -> (# a, b #) pattern OptMResult x y = (# x, y #) {-# COMPLETE OptMResult #-} newtype CmmOptM a = CmmOptM (NCGConfig -> [CLabel] -> OptMResult a) deriving (Functor) instance Applicative CmmOptM where pure x = CmmOptM $ \_ imports -> OptMResult x imports (<*>) = ap instance Monad CmmOptM where (CmmOptM f) >>= g = CmmOptM $ \config imports0 -> case f config imports0 of OptMResult x imports1 -> case g x of CmmOptM g' -> g' config imports1 instance CmmMakeDynamicReferenceM CmmOptM where addImport = addImportCmmOpt addImportCmmOpt :: CLabel -> CmmOptM () addImportCmmOpt lbl = CmmOptM $ \_ imports -> OptMResult () (lbl:imports) getCmmOptConfig :: CmmOptM NCGConfig getCmmOptConfig = CmmOptM $ \config imports -> OptMResult config imports runCmmOpt :: NCGConfig -> CmmOptM a -> (a, [CLabel]) runCmmOpt config (CmmOptM f) = case f config [] of OptMResult result imports -> (result, imports) cmmBlockConFold :: CmmBlock -> CmmOptM CmmBlock cmmBlockConFold block = do let (entry, middle, last) = blockSplit block stmts = blockToList middle stmts' <- mapM cmmStmtConFold stmts last' <- cmmStmtConFold last return $ blockJoin entry (blockFromList stmts') last' -- This does three optimizations, but they're very quick to check, so we don't -- bother turning them off even when the Hoopl code is active. Since -- this is on the old Cmm representation, we can't reuse the code either: -- * reg = reg --> nop -- * if 0 then jump --> nop -- * if 1 then jump --> jump -- We might be tempted to skip this step entirely of not Opt_PIC, but -- there is some PowerPC code for the non-PIC case, which would also -- have to be separated. cmmStmtConFold :: CmmNode e x -> CmmOptM (CmmNode e x) cmmStmtConFold stmt = case stmt of CmmAssign reg src -> do src' <- cmmExprConFold DataReference src return $ case src' of CmmReg reg' | reg == reg' -> CmmComment (fsLit "nop") new_src -> CmmAssign reg new_src CmmStore addr src align -> do addr' <- cmmExprConFold DataReference addr src' <- cmmExprConFold DataReference src return $ CmmStore addr' src' align CmmCall { cml_target = addr } -> do addr' <- cmmExprConFold JumpReference addr return $ stmt { cml_target = addr' } CmmUnsafeForeignCall target regs args -> do target' <- case target of ForeignTarget e conv -> do e' <- cmmExprConFold CallReference e return $ ForeignTarget e' conv PrimTarget _ -> return target args' <- mapM (cmmExprConFold DataReference) args return $ CmmUnsafeForeignCall target' regs args' CmmCondBranch test true false likely -> do test' <- cmmExprConFold DataReference test return $ case test' of CmmLit (CmmInt 0 _) -> CmmBranch false CmmLit (CmmInt _ _) -> CmmBranch true _other -> CmmCondBranch test' true false likely CmmSwitch expr ids -> do expr' <- cmmExprConFold DataReference expr return $ CmmSwitch expr' ids other -> return other cmmExprConFold :: ReferenceKind -> CmmExpr -> CmmOptM CmmExpr cmmExprConFold referenceKind expr = do config <- getCmmOptConfig let expr' = if not (ncgDoConstantFolding config) then expr else cmmExprCon config expr cmmExprNative referenceKind expr' cmmExprCon :: NCGConfig -> CmmExpr -> CmmExpr cmmExprCon config (CmmLoad addr rep align) = CmmLoad (cmmExprCon config addr) rep align cmmExprCon config (CmmMachOp mop args) = cmmMachOpFold (ncgPlatform config) mop (map (cmmExprCon config) args) cmmExprCon _ other = other -- handles both PIC and non-PIC cases... a very strange mixture -- of things to do. cmmExprNative :: ReferenceKind -> CmmExpr -> CmmOptM CmmExpr cmmExprNative referenceKind expr = do config <- getCmmOptConfig let platform = ncgPlatform config arch = platformArch platform case expr of CmmLoad addr rep align -> do addr' <- cmmExprNative DataReference addr return $ CmmLoad addr' rep align CmmMachOp mop args -> do args' <- mapM (cmmExprNative DataReference) args return $ CmmMachOp mop args' CmmLit (CmmBlock id) -> cmmExprNative referenceKind (CmmLit (CmmLabel (infoTblLbl id))) -- we must convert block Ids to CLabels here, because we -- might have to do the PIC transformation. Hence we must -- not modify BlockIds beyond this point. CmmLit (CmmLabel lbl) -> cmmMakeDynamicReference config referenceKind lbl CmmLit (CmmLabelOff lbl off) -> do dynRef <- cmmMakeDynamicReference config referenceKind lbl -- need to optimize here, since it's late return $ cmmMachOpFold platform (MO_Add (wordWidth platform)) [ dynRef, (CmmLit $ CmmInt (fromIntegral off) (wordWidth platform)) ] -- On powerpc (non-PIC), it's easier to jump directly to a label than -- to use the register table, so we replace these registers -- with the corresponding labels: CmmReg (CmmGlobal EagerBlackholeInfo) | arch == ArchPPC && not (ncgPIC config) -> cmmExprNative referenceKind $ CmmLit (CmmLabel (mkCmmCodeLabel rtsUnitId (fsLit "__stg_EAGER_BLACKHOLE_info"))) CmmReg (CmmGlobal GCEnter1) | arch == ArchPPC && not (ncgPIC config) -> cmmExprNative referenceKind $ CmmLit (CmmLabel (mkCmmCodeLabel rtsUnitId (fsLit "__stg_gc_enter_1"))) CmmReg (CmmGlobal GCFun) | arch == ArchPPC && not (ncgPIC config) -> cmmExprNative referenceKind $ CmmLit (CmmLabel (mkCmmCodeLabel rtsUnitId (fsLit "__stg_gc_fun"))) other -> return other