----------------------------------------------------------------------------- -- -- Machine-dependent assembly language -- -- (c) The University of Glasgow 1993-2004 -- ----------------------------------------------------------------------------- #include "HsVersions.h" #include "nativeGen/NCG.h" {-# LANGUAGE TypeFamilies #-} module X86.Instr (Instr(..), Operand(..), PrefetchVariant(..), JumpDest, getJumpDestBlockId, canShortcut, shortcutStatics, shortcutJump, i386_insert_ffrees, allocMoreStack, maxSpillSlots, archWordSize) where import X86.Cond import X86.Regs import Instruction import Size import RegClass import Reg import TargetReg import BlockId import CodeGen.Platform import Cmm import FastString import FastBool import Outputable import Platform import BasicTypes (Alignment) import CLabel import DynFlags import UniqSet import Unique import UniqSupply import Control.Monad import Data.Maybe (fromMaybe) -- Size of an x86/x86_64 memory address, in bytes. -- archWordSize :: Bool -> Size archWordSize is32Bit | is32Bit = II32 | otherwise = II64 -- | Instruction instance for x86 instruction set. instance Instruction Instr where regUsageOfInstr = x86_regUsageOfInstr patchRegsOfInstr = x86_patchRegsOfInstr isJumpishInstr = x86_isJumpishInstr jumpDestsOfInstr = x86_jumpDestsOfInstr patchJumpInstr = x86_patchJumpInstr mkSpillInstr = x86_mkSpillInstr mkLoadInstr = x86_mkLoadInstr takeDeltaInstr = x86_takeDeltaInstr isMetaInstr = x86_isMetaInstr mkRegRegMoveInstr = x86_mkRegRegMoveInstr takeRegRegMoveInstr = x86_takeRegRegMoveInstr mkJumpInstr = x86_mkJumpInstr mkStackAllocInstr = x86_mkStackAllocInstr mkStackDeallocInstr = x86_mkStackDeallocInstr -- ----------------------------------------------------------------------------- -- Intel x86 instructions {- Intel, in their infinite wisdom, selected a stack model for floating point registers on x86. That might have made sense back in 1979 -- nowadays we can see it for the nonsense it really is. A stack model fits poorly with the existing nativeGen infrastructure, which assumes flat integer and FP register sets. Prior to this commit, nativeGen could not generate correct x86 FP code -- to do so would have meant somehow working the register-stack paradigm into the register allocator and spiller, which sounds very difficult. We have decided to cheat, and go for a simple fix which requires no infrastructure modifications, at the expense of generating ropey but correct FP code. All notions of the x86 FP stack and its insns have been removed. Instead, we pretend (to the instruction selector and register allocator) that x86 has six floating point registers, %fake0 .. %fake5, which can be used in the usual flat manner. We further claim that x86 has floating point instructions very similar to SPARC and Alpha, that is, a simple 3-operand register-register arrangement. Code generation and register allocation proceed on this basis. When we come to print out the final assembly, our convenient fiction is converted to dismal reality. Each fake instruction is independently converted to a series of real x86 instructions. %fake0 .. %fake5 are mapped to %st(0) .. %st(5). To do reg-reg arithmetic operations, the two operands are pushed onto the top of the FP stack, the operation done, and the result copied back into the relevant register. There are only six %fake registers because 2 are needed for the translation, and x86 has 8 in total. The translation is inefficient but is simple and it works. A cleverer translation would handle a sequence of insns, simulating the FP stack contents, would not impose a fixed mapping from %fake to %st regs, and hopefully could avoid most of the redundant reg-reg moves of the current translation. We might as well make use of whatever unique FP facilities Intel have chosen to bless us with (let's not be churlish, after all). Hence GLDZ and GLD1. Bwahahahahahahaha! -} {- Note [x86 Floating point precision] Intel's internal floating point registers are by default 80 bit extended precision. This means that all operations done on values in registers are done at 80 bits, and unless the intermediate values are truncated to the appropriate size (32 or 64 bits) by storing in memory, calculations in registers will give different results from calculations which pass intermediate values in memory (eg. via function calls). One solution is to set the FPU into 64 bit precision mode. Some OSs do this (eg. FreeBSD) and some don't (eg. Linux). The problem here is that this will only affect 64-bit precision arithmetic; 32-bit calculations will still be done at 64-bit precision in registers. So it doesn't solve the whole problem. There's also the issue of what the C library is expecting in terms of precision. It seems to be the case that glibc on Linux expects the FPU to be set to 80 bit precision, so setting it to 64 bit could have unexpected effects. Changing the default could have undesirable effects on other 3rd-party library code too, so the right thing would be to save/restore the FPU control word across Haskell code if we were to do this. gcc's -ffloat-store gives consistent results by always storing the results of floating-point calculations in memory, which works for both 32 and 64-bit precision. However, it only affects the values of user-declared floating point variables in C, not intermediate results. GHC in -fvia-C mode uses -ffloat-store (see the -fexcess-precision flag). Another problem is how to spill floating point registers in the register allocator. Should we spill the whole 80 bits, or just 64? On an OS which is set to 64 bit precision, spilling 64 is fine. On Linux, spilling 64 bits will round the results of some operations. This is what gcc does. Spilling at 80 bits requires taking up a full 128 bit slot (so we get alignment). We spill at 80-bits and ignore the alignment problems. In the future [edit: now available in GHC 7.0.1, with the -msse2 flag], we'll use the SSE registers for floating point. This requires a CPU that supports SSE2 (ordinary SSE only supports 32 bit precision float ops), which means P4 or Xeon and above. Using SSE will solve all these problems, because the SSE registers use fixed 32 bit or 64 bit precision. --SDM 1/2003 -} data Instr -- comment pseudo-op = COMMENT FastString -- some static data spat out during code -- generation. Will be extracted before -- pretty-printing. | LDATA Section (Alignment, CmmStatics) -- start a new basic block. Useful during -- codegen, removed later. Preceding -- instruction should be a jump, as per the -- invariants for a BasicBlock (see Cmm). | NEWBLOCK BlockId -- specify current stack offset for -- benefit of subsequent passes | DELTA Int -- Moves. | MOV Size Operand Operand | MOVZxL Size Operand Operand -- size is the size of operand 1 | MOVSxL Size Operand Operand -- size is the size of operand 1 -- Special case move for Ivy Bridge processors | REPMOVSB -- x86_64 note: plain mov into a 32-bit register always zero-extends -- into the 64-bit reg, in contrast to the 8 and 16-bit movs which -- don't affect the high bits of the register. -- Load effective address (also a very useful three-operand add instruction :-) | LEA Size Operand Operand -- Int Arithmetic. | ADD Size Operand Operand | ADC Size Operand Operand | SUB Size Operand Operand | MUL Size Operand Operand | MUL2 Size Operand -- %edx:%eax = operand * %rax | IMUL Size Operand Operand -- signed int mul | IMUL2 Size Operand -- %edx:%eax = operand * %eax | DIV Size Operand -- eax := eax:edx/op, edx := eax:edx%op | IDIV Size Operand -- ditto, but signed -- Simple bit-twiddling. | AND Size Operand Operand | OR Size Operand Operand | XOR Size Operand Operand | NOT Size Operand | NEGI Size Operand -- NEG instruction (name clash with Cond) | BSWAP Size Reg -- Shifts (amount may be immediate or %cl only) | SHL Size Operand{-amount-} Operand | SAR Size Operand{-amount-} Operand | SHR Size Operand{-amount-} Operand | BT Size Imm Operand | NOP -- x86 Float Arithmetic. -- Note that we cheat by treating G{ABS,MOV,NEG} of doubles -- as single instructions right up until we spit them out. -- all the 3-operand fake fp insns are src1 src2 dst -- and furthermore are constrained to be fp regs only. -- IMPORTANT: keep is_G_insn up to date with any changes here | GMOV Reg Reg -- src(fpreg), dst(fpreg) | GLD Size AddrMode Reg -- src, dst(fpreg) | GST Size Reg AddrMode -- src(fpreg), dst | GLDZ Reg -- dst(fpreg) | GLD1 Reg -- dst(fpreg) | GFTOI Reg Reg -- src(fpreg), dst(intreg) | GDTOI Reg Reg -- src(fpreg), dst(intreg) | GITOF Reg Reg -- src(intreg), dst(fpreg) | GITOD Reg Reg -- src(intreg), dst(fpreg) | GDTOF Reg Reg -- src(fpreg), dst(fpreg) | GADD Size Reg Reg Reg -- src1, src2, dst | GDIV Size Reg Reg Reg -- src1, src2, dst | GSUB Size Reg Reg Reg -- src1, src2, dst | GMUL Size Reg Reg Reg -- src1, src2, dst -- FP compare. Cond must be `elem` [EQQ, NE, LE, LTT, GE, GTT] -- Compare src1 with src2; set the Zero flag iff the numbers are -- comparable and the comparison is True. Subsequent code must -- test the %eflags zero flag regardless of the supplied Cond. | GCMP Cond Reg Reg -- src1, src2 | GABS Size Reg Reg -- src, dst | GNEG Size Reg Reg -- src, dst | GSQRT Size Reg Reg -- src, dst | GSIN Size CLabel CLabel Reg Reg -- src, dst | GCOS Size CLabel CLabel Reg Reg -- src, dst | GTAN Size CLabel CLabel Reg Reg -- src, dst | GFREE -- do ffree on all x86 regs; an ugly hack -- SSE2 floating point: we use a restricted set of the available SSE2 -- instructions for floating-point. -- use MOV for moving (either movss or movsd (movlpd better?)) | CVTSS2SD Reg Reg -- F32 to F64 | CVTSD2SS Reg Reg -- F64 to F32 | CVTTSS2SIQ Size Operand Reg -- F32 to I32/I64 (with truncation) | CVTTSD2SIQ Size Operand Reg -- F64 to I32/I64 (with truncation) | CVTSI2SS Size Operand Reg -- I32/I64 to F32 | CVTSI2SD Size Operand Reg -- I32/I64 to F64 -- use ADD & SUB for arithmetic. In both cases, operands -- are Operand Reg. -- SSE2 floating-point division: | FDIV Size Operand Operand -- divisor, dividend(dst) -- use CMP for comparisons. ucomiss and ucomisd instructions -- compare single/double prec floating point respectively. | SQRT Size Operand Reg -- src, dst -- Comparison | TEST Size Operand Operand | CMP Size Operand Operand | SETCC Cond Operand -- Stack Operations. | PUSH Size Operand | POP Size Operand -- both unused (SDM): -- | PUSHA -- | POPA -- Jumping around. | JMP Operand [Reg] -- including live Regs at the call | JXX Cond BlockId -- includes unconditional branches | JXX_GBL Cond Imm -- non-local version of JXX -- Table jump | JMP_TBL Operand -- Address to jump to [Maybe BlockId] -- Blocks in the jump table Section -- Data section jump table should be put in CLabel -- Label of jump table | CALL (Either Imm Reg) [Reg] -- Other things. | CLTD Size -- sign extend %eax into %edx:%eax | FETCHGOT Reg -- pseudo-insn for ELF position-independent code -- pretty-prints as -- call 1f -- 1: popl %reg -- addl __GLOBAL_OFFSET_TABLE__+.-1b, %reg | FETCHPC Reg -- pseudo-insn for Darwin position-independent code -- pretty-prints as -- call 1f -- 1: popl %reg -- SSE4.2 | POPCNT Size Operand Reg -- src, dst -- prefetch | PREFETCH PrefetchVariant Size Operand -- prefetch Variant, addr size, address to prefetch -- variant can be NTA, Lvl0, Lvl1, or Lvl2 data PrefetchVariant = NTA | Lvl0 | Lvl1 | Lvl2 data Operand = OpReg Reg -- register | OpImm Imm -- immediate value | OpAddr AddrMode -- memory reference x86_regUsageOfInstr :: Platform -> Instr -> RegUsage x86_regUsageOfInstr platform instr = case instr of MOV _ src dst -> usageRW src dst MOVZxL _ src dst -> usageRW src dst MOVSxL _ src dst -> usageRW src dst LEA _ src dst -> usageRW src dst ADD _ src dst -> usageRM src dst ADC _ src dst -> usageRM src dst SUB _ src dst -> usageRM src dst IMUL _ src dst -> usageRM src dst IMUL2 _ src -> mkRU (eax:use_R src []) [eax,edx] MUL _ src dst -> usageRM src dst MUL2 _ src -> mkRU (eax:use_R src []) [eax,edx] DIV _ op -> mkRU (eax:edx:use_R op []) [eax,edx] IDIV _ op -> mkRU (eax:edx:use_R op []) [eax,edx] AND _ src dst -> usageRM src dst OR _ src dst -> usageRM src dst XOR _ (OpReg src) (OpReg dst) | src == dst -> mkRU [] [dst] XOR _ src dst -> usageRM src dst NOT _ op -> usageM op BSWAP _ reg -> mkRU [reg] [reg] NEGI _ op -> usageM op SHL _ imm dst -> usageRM imm dst SAR _ imm dst -> usageRM imm dst SHR _ imm dst -> usageRM imm dst BT _ _ src -> mkRUR (use_R src []) PUSH _ op -> mkRUR (use_R op []) POP _ op -> mkRU [] (def_W op) TEST _ src dst -> mkRUR (use_R src $! use_R dst []) CMP _ src dst -> mkRUR (use_R src $! use_R dst []) SETCC _ op -> mkRU [] (def_W op) JXX _ _ -> mkRU [] [] JXX_GBL _ _ -> mkRU [] [] JMP op regs -> mkRUR (use_R op regs) JMP_TBL op _ _ _ -> mkRUR (use_R op []) CALL (Left _) params -> mkRU params (callClobberedRegs platform) CALL (Right reg) params -> mkRU (reg:params) (callClobberedRegs platform) CLTD _ -> mkRU [eax] [edx] NOP -> mkRU [] [] GMOV src dst -> mkRU [src] [dst] GLD _ src dst -> mkRU (use_EA src []) [dst] GST _ src dst -> mkRUR (src : use_EA dst []) GLDZ dst -> mkRU [] [dst] GLD1 dst -> mkRU [] [dst] GFTOI src dst -> mkRU [src] [dst] GDTOI src dst -> mkRU [src] [dst] GITOF src dst -> mkRU [src] [dst] GITOD src dst -> mkRU [src] [dst] GDTOF src dst -> mkRU [src] [dst] GADD _ s1 s2 dst -> mkRU [s1,s2] [dst] GSUB _ s1 s2 dst -> mkRU [s1,s2] [dst] GMUL _ s1 s2 dst -> mkRU [s1,s2] [dst] GDIV _ s1 s2 dst -> mkRU [s1,s2] [dst] GCMP _ src1 src2 -> mkRUR [src1,src2] GABS _ src dst -> mkRU [src] [dst] GNEG _ src dst -> mkRU [src] [dst] GSQRT _ src dst -> mkRU [src] [dst] GSIN _ _ _ src dst -> mkRU [src] [dst] GCOS _ _ _ src dst -> mkRU [src] [dst] GTAN _ _ _ src dst -> mkRU [src] [dst] CVTSS2SD src dst -> mkRU [src] [dst] CVTSD2SS src dst -> mkRU [src] [dst] CVTTSS2SIQ _ src dst -> mkRU (use_R src []) [dst] CVTTSD2SIQ _ src dst -> mkRU (use_R src []) [dst] CVTSI2SS _ src dst -> mkRU (use_R src []) [dst] CVTSI2SD _ src dst -> mkRU (use_R src []) [dst] FDIV _ src dst -> usageRM src dst FETCHGOT reg -> mkRU [] [reg] FETCHPC reg -> mkRU [] [reg] COMMENT _ -> noUsage DELTA _ -> noUsage POPCNT _ src dst -> mkRU (use_R src []) [dst] REPMOVSB -> mkRU [] [] -- note: might be a better way to do this PREFETCH _ _ src -> mkRU (use_R src []) [] _other -> panic "regUsage: unrecognised instr" where -- 2 operand form; first operand Read; second Written usageRW :: Operand -> Operand -> RegUsage usageRW op (OpReg reg) = mkRU (use_R op []) [reg] usageRW op (OpAddr ea) = mkRUR (use_R op $! use_EA ea []) usageRW _ _ = panic "X86.RegInfo.usageRW: no match" -- 2 operand form; first operand Read; second Modified usageRM :: Operand -> Operand -> RegUsage usageRM op (OpReg reg) = mkRU (use_R op [reg]) [reg] usageRM op (OpAddr ea) = mkRUR (use_R op $! use_EA ea []) usageRM _ _ = panic "X86.RegInfo.usageRM: no match" -- 1 operand form; operand Modified usageM :: Operand -> RegUsage usageM (OpReg reg) = mkRU [reg] [reg] usageM (OpAddr ea) = mkRUR (use_EA ea []) usageM _ = panic "X86.RegInfo.usageM: no match" -- Registers defd when an operand is written. def_W (OpReg reg) = [reg] def_W (OpAddr _ ) = [] def_W _ = panic "X86.RegInfo.def_W: no match" -- Registers used when an operand is read. use_R (OpReg reg) tl = reg : tl use_R (OpImm _) tl = tl use_R (OpAddr ea) tl = use_EA ea tl -- Registers used to compute an effective address. use_EA (ImmAddr _ _) tl = tl use_EA (AddrBaseIndex base index _) tl = use_base base $! use_index index tl where use_base (EABaseReg r) tl = r : tl use_base _ tl = tl use_index EAIndexNone tl = tl use_index (EAIndex i _) tl = i : tl mkRUR src = src' `seq` RU src' [] where src' = filter (interesting platform) src mkRU src dst = src' `seq` dst' `seq` RU src' dst' where src' = filter (interesting platform) src dst' = filter (interesting platform) dst interesting :: Platform -> Reg -> Bool interesting _ (RegVirtual _) = True interesting platform (RegReal (RealRegSingle i)) = isFastTrue (freeReg platform i) interesting _ (RegReal (RealRegPair{})) = panic "X86.interesting: no reg pairs on this arch" x86_patchRegsOfInstr :: Instr -> (Reg -> Reg) -> Instr x86_patchRegsOfInstr instr env = case instr of MOV sz src dst -> patch2 (MOV sz) src dst MOVZxL sz src dst -> patch2 (MOVZxL sz) src dst MOVSxL sz src dst -> patch2 (MOVSxL sz) src dst LEA sz src dst -> patch2 (LEA sz) src dst ADD sz src dst -> patch2 (ADD sz) src dst ADC sz src dst -> patch2 (ADC sz) src dst SUB sz src dst -> patch2 (SUB sz) src dst IMUL sz src dst -> patch2 (IMUL sz) src dst IMUL2 sz src -> patch1 (IMUL2 sz) src MUL sz src dst -> patch2 (MUL sz) src dst MUL2 sz src -> patch1 (MUL2 sz) src IDIV sz op -> patch1 (IDIV sz) op DIV sz op -> patch1 (DIV sz) op AND sz src dst -> patch2 (AND sz) src dst OR sz src dst -> patch2 (OR sz) src dst XOR sz src dst -> patch2 (XOR sz) src dst NOT sz op -> patch1 (NOT sz) op BSWAP sz reg -> BSWAP sz (env reg) NEGI sz op -> patch1 (NEGI sz) op SHL sz imm dst -> patch1 (SHL sz imm) dst SAR sz imm dst -> patch1 (SAR sz imm) dst SHR sz imm dst -> patch1 (SHR sz imm) dst BT sz imm src -> patch1 (BT sz imm) src TEST sz src dst -> patch2 (TEST sz) src dst CMP sz src dst -> patch2 (CMP sz) src dst PUSH sz op -> patch1 (PUSH sz) op POP sz op -> patch1 (POP sz) op SETCC cond op -> patch1 (SETCC cond) op JMP op regs -> JMP (patchOp op) regs JMP_TBL op ids s lbl-> JMP_TBL (patchOp op) ids s lbl GMOV src dst -> GMOV (env src) (env dst) GLD sz src dst -> GLD sz (lookupAddr src) (env dst) GST sz src dst -> GST sz (env src) (lookupAddr dst) GLDZ dst -> GLDZ (env dst) GLD1 dst -> GLD1 (env dst) GFTOI src dst -> GFTOI (env src) (env dst) GDTOI src dst -> GDTOI (env src) (env dst) GITOF src dst -> GITOF (env src) (env dst) GITOD src dst -> GITOD (env src) (env dst) GDTOF src dst -> GDTOF (env src) (env dst) GADD sz s1 s2 dst -> GADD sz (env s1) (env s2) (env dst) GSUB sz s1 s2 dst -> GSUB sz (env s1) (env s2) (env dst) GMUL sz s1 s2 dst -> GMUL sz (env s1) (env s2) (env dst) GDIV sz s1 s2 dst -> GDIV sz (env s1) (env s2) (env dst) GCMP sz src1 src2 -> GCMP sz (env src1) (env src2) GABS sz src dst -> GABS sz (env src) (env dst) GNEG sz src dst -> GNEG sz (env src) (env dst) GSQRT sz src dst -> GSQRT sz (env src) (env dst) GSIN sz l1 l2 src dst -> GSIN sz l1 l2 (env src) (env dst) GCOS sz l1 l2 src dst -> GCOS sz l1 l2 (env src) (env dst) GTAN sz l1 l2 src dst -> GTAN sz l1 l2 (env src) (env dst) CVTSS2SD src dst -> CVTSS2SD (env src) (env dst) CVTSD2SS src dst -> CVTSD2SS (env src) (env dst) CVTTSS2SIQ sz src dst -> CVTTSS2SIQ sz (patchOp src) (env dst) CVTTSD2SIQ sz src dst -> CVTTSD2SIQ sz (patchOp src) (env dst) CVTSI2SS sz src dst -> CVTSI2SS sz (patchOp src) (env dst) CVTSI2SD sz src dst -> CVTSI2SD sz (patchOp src) (env dst) FDIV sz src dst -> FDIV sz (patchOp src) (patchOp dst) CALL (Left _) _ -> instr CALL (Right reg) p -> CALL (Right (env reg)) p FETCHGOT reg -> FETCHGOT (env reg) FETCHPC reg -> FETCHPC (env reg) NOP -> instr COMMENT _ -> instr DELTA _ -> instr JXX _ _ -> instr JXX_GBL _ _ -> instr CLTD _ -> instr POPCNT sz src dst -> POPCNT sz (patchOp src) (env dst) PREFETCH lvl size src -> PREFETCH lvl size (patchOp src) REPMOVSB -> REPMOVSB _other -> panic "patchRegs: unrecognised instr" where patch1 :: (Operand -> a) -> Operand -> a patch1 insn op = insn $! patchOp op patch2 :: (Operand -> Operand -> a) -> Operand -> Operand -> a patch2 insn src dst = (insn $! patchOp src) $! patchOp dst patchOp (OpReg reg) = OpReg $! env reg patchOp (OpImm imm) = OpImm imm patchOp (OpAddr ea) = OpAddr $! lookupAddr ea lookupAddr (ImmAddr imm off) = ImmAddr imm off lookupAddr (AddrBaseIndex base index disp) = ((AddrBaseIndex $! lookupBase base) $! lookupIndex index) disp where lookupBase EABaseNone = EABaseNone lookupBase EABaseRip = EABaseRip lookupBase (EABaseReg r) = EABaseReg $! env r lookupIndex EAIndexNone = EAIndexNone lookupIndex (EAIndex r i) = (EAIndex $! env r) i -------------------------------------------------------------------------------- x86_isJumpishInstr :: Instr -> Bool x86_isJumpishInstr instr = case instr of JMP{} -> True JXX{} -> True JXX_GBL{} -> True JMP_TBL{} -> True CALL{} -> True _ -> False x86_jumpDestsOfInstr :: Instr -> [BlockId] x86_jumpDestsOfInstr insn = case insn of JXX _ id -> [id] JMP_TBL _ ids _ _ -> [id | Just id <- ids] _ -> [] x86_patchJumpInstr :: Instr -> (BlockId -> BlockId) -> Instr x86_patchJumpInstr insn patchF = case insn of JXX cc id -> JXX cc (patchF id) JMP_TBL op ids section lbl -> JMP_TBL op (map (fmap patchF) ids) section lbl _ -> insn -- ----------------------------------------------------------------------------- -- | Make a spill instruction. x86_mkSpillInstr :: DynFlags -> Reg -- register to spill -> Int -- current stack delta -> Int -- spill slot to use -> Instr x86_mkSpillInstr dflags reg delta slot = let off = spillSlotToOffset platform slot - delta in case targetClassOfReg platform reg of RcInteger -> MOV (archWordSize is32Bit) (OpReg reg) (OpAddr (spRel dflags off)) RcDouble -> GST FF80 reg (spRel dflags off) {- RcFloat/RcDouble -} RcDoubleSSE -> MOV FF64 (OpReg reg) (OpAddr (spRel dflags off)) _ -> panic "X86.mkSpillInstr: no match" where platform = targetPlatform dflags is32Bit = target32Bit platform -- | Make a spill reload instruction. x86_mkLoadInstr :: DynFlags -> Reg -- register to load -> Int -- current stack delta -> Int -- spill slot to use -> Instr x86_mkLoadInstr dflags reg delta slot = let off = spillSlotToOffset platform slot - delta in case targetClassOfReg platform reg of RcInteger -> MOV (archWordSize is32Bit) (OpAddr (spRel dflags off)) (OpReg reg) RcDouble -> GLD FF80 (spRel dflags off) reg {- RcFloat/RcDouble -} RcDoubleSSE -> MOV FF64 (OpAddr (spRel dflags off)) (OpReg reg) _ -> panic "X86.x86_mkLoadInstr" where platform = targetPlatform dflags is32Bit = target32Bit platform spillSlotSize :: Platform -> Int spillSlotSize dflags = if is32Bit then 12 else 8 where is32Bit = target32Bit dflags maxSpillSlots :: DynFlags -> Int maxSpillSlots dflags = ((rESERVED_C_STACK_BYTES dflags - 64) `div` spillSlotSize (targetPlatform dflags)) - 1 -- = 0 -- useful for testing allocMoreStack -- number of bytes that the stack pointer should be aligned to stackAlign :: Int stackAlign = 16 -- convert a spill slot number to a *byte* offset, with no sign: -- decide on a per arch basis whether you are spilling above or below -- the C stack pointer. spillSlotToOffset :: Platform -> Int -> Int spillSlotToOffset platform slot = 64 + spillSlotSize platform * slot -------------------------------------------------------------------------------- -- | See if this instruction is telling us the current C stack delta x86_takeDeltaInstr :: Instr -> Maybe Int x86_takeDeltaInstr instr = case instr of DELTA i -> Just i _ -> Nothing x86_isMetaInstr :: Instr -> Bool x86_isMetaInstr instr = case instr of COMMENT{} -> True LDATA{} -> True NEWBLOCK{} -> True DELTA{} -> True _ -> False -- | Make a reg-reg move instruction. -- On SPARC v8 there are no instructions to move directly between -- floating point and integer regs. If we need to do that then we -- have to go via memory. -- x86_mkRegRegMoveInstr :: Platform -> Reg -> Reg -> Instr x86_mkRegRegMoveInstr platform src dst = case targetClassOfReg platform src of RcInteger -> case platformArch platform of ArchX86 -> MOV II32 (OpReg src) (OpReg dst) ArchX86_64 -> MOV II64 (OpReg src) (OpReg dst) _ -> panic "x86_mkRegRegMoveInstr: Bad arch" RcDouble -> GMOV src dst RcDoubleSSE -> MOV FF64 (OpReg src) (OpReg dst) _ -> panic "X86.RegInfo.mkRegRegMoveInstr: no match" -- | Check whether an instruction represents a reg-reg move. -- The register allocator attempts to eliminate reg->reg moves whenever it can, -- by assigning the src and dest temporaries to the same real register. -- x86_takeRegRegMoveInstr :: Instr -> Maybe (Reg,Reg) x86_takeRegRegMoveInstr (MOV _ (OpReg r1) (OpReg r2)) = Just (r1,r2) x86_takeRegRegMoveInstr _ = Nothing -- | Make an unconditional branch instruction. x86_mkJumpInstr :: BlockId -> [Instr] x86_mkJumpInstr id = [JXX ALWAYS id] x86_mkStackAllocInstr :: Platform -> Int -> Instr x86_mkStackAllocInstr platform amount = case platformArch platform of ArchX86 -> SUB II32 (OpImm (ImmInt amount)) (OpReg esp) ArchX86_64 -> SUB II64 (OpImm (ImmInt amount)) (OpReg rsp) _ -> panic "x86_mkStackAllocInstr" x86_mkStackDeallocInstr :: Platform -> Int -> Instr x86_mkStackDeallocInstr platform amount = case platformArch platform of ArchX86 -> ADD II32 (OpImm (ImmInt amount)) (OpReg esp) ArchX86_64 -> ADD II64 (OpImm (ImmInt amount)) (OpReg rsp) _ -> panic "x86_mkStackDeallocInstr" i386_insert_ffrees :: [GenBasicBlock Instr] -> [GenBasicBlock Instr] i386_insert_ffrees blocks | any (any is_G_instr) [ instrs | BasicBlock _ instrs <- blocks ] = map insertGFREEs blocks | otherwise = blocks where insertGFREEs (BasicBlock id insns) = BasicBlock id (insertBeforeNonlocalTransfers GFREE insns) insertBeforeNonlocalTransfers :: Instr -> [Instr] -> [Instr] insertBeforeNonlocalTransfers insert insns = foldr p [] insns where p insn r = case insn of CALL _ _ -> insert : insn : r JMP _ _ -> insert : insn : r JXX_GBL _ _ -> panic "insertBeforeNonlocalTransfers: cannot handle JXX_GBL" _ -> insn : r -- if you ever add a new FP insn to the fake x86 FP insn set, -- you must update this too is_G_instr :: Instr -> Bool is_G_instr instr = case instr of GMOV{} -> True GLD{} -> True GST{} -> True GLDZ{} -> True GLD1{} -> True GFTOI{} -> True GDTOI{} -> True GITOF{} -> True GITOD{} -> True GDTOF{} -> True GADD{} -> True GDIV{} -> True GSUB{} -> True GMUL{} -> True GCMP{} -> True GABS{} -> True GNEG{} -> True GSQRT{} -> True GSIN{} -> True GCOS{} -> True GTAN{} -> True GFREE -> panic "is_G_instr: GFREE (!)" _ -> False -- -- Note [extra spill slots] -- -- If the register allocator used more spill slots than we have -- pre-allocated (rESERVED_C_STACK_BYTES), then we must allocate more -- C stack space on entry and exit from this proc. Therefore we -- insert a "sub $N, %rsp" at every entry point, and an "add $N, %rsp" -- before every non-local jump. -- -- This became necessary when the new codegen started bundling entire -- functions together into one proc, because the register allocator -- assigns a different stack slot to each virtual reg within a proc. -- To avoid using so many slots we could also: -- -- - split up the proc into connected components before code generator -- -- - rename the virtual regs, so that we re-use vreg names and hence -- stack slots for non-overlapping vregs. -- -- Note that when a block is both a non-local entry point (with an -- info table) and a local branch target, we have to split it into -- two, like so: -- -- -- L: -- -- -- becomes -- -- -- L: -- subl $rsp, N -- jmp Lnew -- Lnew: -- -- -- and all branches pointing to L are retargetted to point to Lnew. -- Otherwise, we would repeat the $rsp adjustment for each branch to -- L. -- allocMoreStack :: Platform -> Int -> NatCmmDecl statics X86.Instr.Instr -> UniqSM (NatCmmDecl statics X86.Instr.Instr) allocMoreStack _ _ top@(CmmData _ _) = return top allocMoreStack platform slots proc@(CmmProc info lbl live (ListGraph code)) = do let entries = entryBlocks proc uniqs <- replicateM (length entries) getUniqueUs let delta = ((x + stackAlign - 1) `quot` stackAlign) * stackAlign -- round up where x = slots * spillSlotSize platform -- sp delta alloc = mkStackAllocInstr platform delta dealloc = mkStackDeallocInstr platform delta new_blockmap :: BlockEnv BlockId new_blockmap = mapFromList (zip entries (map mkBlockId uniqs)) insert_stack_insns (BasicBlock id insns) | Just new_blockid <- mapLookup id new_blockmap = [ BasicBlock id [alloc, JXX ALWAYS new_blockid] , BasicBlock new_blockid block' ] | otherwise = [ BasicBlock id block' ] where block' = foldr insert_dealloc [] insns insert_dealloc insn r = case insn of JMP _ _ -> dealloc : insn : r JXX_GBL _ _ -> panic "insert_dealloc: cannot handle JXX_GBL" _other -> x86_patchJumpInstr insn retarget : r where retarget b = fromMaybe b (mapLookup b new_blockmap) new_code = concatMap insert_stack_insns code -- in return (CmmProc info lbl live (ListGraph new_code)) data JumpDest = DestBlockId BlockId | DestImm Imm getJumpDestBlockId :: JumpDest -> Maybe BlockId getJumpDestBlockId (DestBlockId bid) = Just bid getJumpDestBlockId _ = Nothing canShortcut :: Instr -> Maybe JumpDest canShortcut (JXX ALWAYS id) = Just (DestBlockId id) canShortcut (JMP (OpImm imm) _) = Just (DestImm imm) canShortcut _ = Nothing -- This helper shortcuts a sequence of branches. -- The blockset helps avoid following cycles. shortcutJump :: (BlockId -> Maybe JumpDest) -> Instr -> Instr shortcutJump fn insn = shortcutJump' fn (setEmpty :: BlockSet) insn where shortcutJump' fn seen insn@(JXX cc id) = if setMember id seen then insn else case fn id of Nothing -> insn Just (DestBlockId id') -> shortcutJump' fn seen' (JXX cc id') Just (DestImm imm) -> shortcutJump' fn seen' (JXX_GBL cc imm) where seen' = setInsert id seen shortcutJump' _ _ other = other -- Here because it knows about JumpDest shortcutStatics :: (BlockId -> Maybe JumpDest) -> (Alignment, CmmStatics) -> (Alignment, CmmStatics) shortcutStatics fn (align, Statics lbl statics) = (align, Statics lbl $ map (shortcutStatic fn) statics) -- we need to get the jump tables, so apply the mapping to the entries -- of a CmmData too. shortcutLabel :: (BlockId -> Maybe JumpDest) -> CLabel -> CLabel shortcutLabel fn lab | Just uq <- maybeAsmTemp lab = shortBlockId fn emptyUniqSet (mkBlockId uq) | otherwise = lab shortcutStatic :: (BlockId -> Maybe JumpDest) -> CmmStatic -> CmmStatic shortcutStatic fn (CmmStaticLit (CmmLabel lab)) = CmmStaticLit (CmmLabel (shortcutLabel fn lab)) shortcutStatic fn (CmmStaticLit (CmmLabelDiffOff lbl1 lbl2 off)) = CmmStaticLit (CmmLabelDiffOff (shortcutLabel fn lbl1) lbl2 off) -- slightly dodgy, we're ignoring the second label, but this -- works with the way we use CmmLabelDiffOff for jump tables now. shortcutStatic _ other_static = other_static shortBlockId :: (BlockId -> Maybe JumpDest) -> UniqSet Unique -> BlockId -> CLabel shortBlockId fn seen blockid = case (elementOfUniqSet uq seen, fn blockid) of (True, _) -> mkAsmTempLabel uq (_, Nothing) -> mkAsmTempLabel uq (_, Just (DestBlockId blockid')) -> shortBlockId fn (addOneToUniqSet seen uq) blockid' (_, Just (DestImm (ImmCLbl lbl))) -> lbl (_, _other) -> panic "shortBlockId" where uq = getUnique blockid