+++ /dev/null
------------------------------------------------------------------------------
---
--- Cmm utilities.
---
--- (c) The University of Glasgow 2004
---
------------------------------------------------------------------------------
-
-module CmmUtils(
- CmmStmts, noStmts, oneStmt, mkStmts, plusStmts, stmtList,
- isNopStmt,
-
- isTrivialCmmExpr, hasNoGlobalRegs,
-
- cmmRegOff, cmmLabelOff, cmmOffset, cmmOffsetLit, cmmIndex,
- cmmOffsetExpr, cmmIndexExpr, cmmLoadIndex,
-
- mkIntCLit, zeroCLit,
-
- mkLblExpr,
- ) where
-
-#include "HsVersions.h"
-
-import CLabel ( CLabel )
-import Cmm
-import MachOp
-import OrdList
-import Outputable
-
----------------------------------------------------
---
--- CmmStmts
---
----------------------------------------------------
-
-type CmmStmts = OrdList CmmStmt
-
-noStmts :: CmmStmts
-noStmts = nilOL
-
-oneStmt :: CmmStmt -> CmmStmts
-oneStmt = unitOL
-
-mkStmts :: [CmmStmt] -> CmmStmts
-mkStmts = toOL
-
-plusStmts :: CmmStmts -> CmmStmts -> CmmStmts
-plusStmts = appOL
-
-stmtList :: CmmStmts -> [CmmStmt]
-stmtList = fromOL
-
-
----------------------------------------------------
---
--- CmmStmt
---
----------------------------------------------------
-
-isNopStmt :: CmmStmt -> Bool
--- If isNopStmt returns True, the stmt is definitely a no-op;
--- but it might be a no-op even if isNopStmt returns False
-isNopStmt CmmNop = True
-isNopStmt (CmmAssign r e) = cheapEqReg r e
-isNopStmt (CmmStore e1 (CmmLoad e2 _)) = cheapEqExpr e1 e2
-isNopStmt s = False
-
-cheapEqExpr :: CmmExpr -> CmmExpr -> Bool
-cheapEqExpr (CmmReg r) e = cheapEqReg r e
-cheapEqExpr (CmmRegOff r 0) e = cheapEqReg r e
-cheapEqExpr (CmmRegOff r n) (CmmRegOff r' n') = r==r' && n==n'
-cheapEqExpr e1 e2 = False
-
-cheapEqReg :: CmmReg -> CmmExpr -> Bool
-cheapEqReg r (CmmReg r') = r==r'
-cheapEqReg r (CmmRegOff r' 0) = r==r'
-cheapEqReg r e = False
-
----------------------------------------------------
---
--- CmmExpr
---
----------------------------------------------------
-
-isTrivialCmmExpr :: CmmExpr -> Bool
-isTrivialCmmExpr (CmmLoad _ _) = False
-isTrivialCmmExpr (CmmMachOp _ _) = False
-isTrivialCmmExpr (CmmLit _) = True
-isTrivialCmmExpr (CmmReg _) = True
-isTrivialCmmExpr (CmmRegOff _ _) = True
-
-hasNoGlobalRegs :: CmmExpr -> Bool
-hasNoGlobalRegs (CmmLoad e _) = hasNoGlobalRegs e
-hasNoGlobalRegs (CmmMachOp _ es) = all hasNoGlobalRegs es
-hasNoGlobalRegs (CmmLit _) = True
-hasNoGlobalRegs (CmmReg (CmmLocal _)) = True
-hasNoGlobalRegs (CmmRegOff (CmmLocal _) _) = True
-hasNoGlobalRegs _ = False
-
----------------------------------------------------
---
--- Expr Construction helpers
---
----------------------------------------------------
-
-cmmOffsetExpr :: CmmExpr -> CmmExpr -> CmmExpr
--- assumes base and offset have the same MachRep
-cmmOffsetExpr e (CmmLit (CmmInt n _)) = cmmOffset e (fromInteger n)
-cmmOffsetExpr e byte_off = CmmMachOp (MO_Add (cmmExprRep e)) [e, byte_off]
-
--- NB. Do *not* inspect the value of the offset in these smart constructors!!!
---
--- because the offset is sometimes involved in a loop in the code generator
--- (we don't know the real Hp offset until we've generated code for the entire
--- basic block, for example). So we cannot eliminate zero offsets at this
--- stage; they're eliminated later instead (either during printing or
--- a later optimisation step on Cmm).
---
-cmmOffset :: CmmExpr -> Int -> CmmExpr
-cmmOffset (CmmReg reg) byte_off = cmmRegOff reg byte_off
-cmmOffset (CmmRegOff reg m) byte_off = cmmRegOff reg (m+byte_off)
-cmmOffset (CmmLit lit) byte_off = CmmLit (cmmOffsetLit lit byte_off)
-cmmOffset (CmmMachOp (MO_Add rep) [expr, CmmLit (CmmInt byte_off1 _rep)]) byte_off2
- = CmmMachOp (MO_Add rep)
- [expr, CmmLit (CmmInt (byte_off1 + toInteger byte_off2) rep)]
-cmmOffset expr byte_off
- = CmmMachOp (MO_Add rep) [expr, CmmLit (CmmInt (toInteger byte_off) rep)]
- where
- rep = cmmExprRep expr
-
--- Smart constructor for CmmRegOff. Same caveats as cmmOffset above.
-cmmRegOff :: CmmReg -> Int -> CmmExpr
-cmmRegOff reg byte_off = CmmRegOff reg byte_off
-
-cmmOffsetLit :: CmmLit -> Int -> CmmLit
-cmmOffsetLit (CmmLabel l) byte_off = cmmLabelOff l byte_off
-cmmOffsetLit (CmmLabelOff l m) byte_off = cmmLabelOff l (m+byte_off)
-cmmOffsetLit (CmmInt m rep) byte_off = CmmInt (m + fromIntegral byte_off) rep
-cmmOffsetLit other byte_off = pprPanic "cmmOffsetLit" (ppr byte_off)
-
-cmmLabelOff :: CLabel -> Int -> CmmLit
--- Smart constructor for CmmLabelOff
-cmmLabelOff lbl 0 = CmmLabel lbl
-cmmLabelOff lbl byte_off = CmmLabelOff lbl byte_off
-
--- | Useful for creating an index into an array, with a staticaly known offset.
-cmmIndex :: MachRep -> CmmExpr -> Int -> CmmExpr
-cmmIndex rep base idx = cmmOffset base (idx * machRepByteWidth rep)
-
--- | Useful for creating an index into an array, with an unknown offset.
-cmmIndexExpr :: MachRep -> CmmExpr -> CmmExpr -> CmmExpr
-cmmIndexExpr rep base (CmmLit (CmmInt n _)) = cmmIndex rep base (fromInteger n)
-cmmIndexExpr rep base idx =
- cmmOffsetExpr base byte_off
- where
- idx_rep = cmmExprRep idx
- byte_off = CmmMachOp (MO_Shl idx_rep) [
- idx, CmmLit (mkIntCLit (machRepLogWidth rep))]
-
-cmmLoadIndex :: MachRep -> CmmExpr -> Int -> CmmExpr
-cmmLoadIndex rep expr ix = CmmLoad (cmmIndex rep expr ix) rep
-
----------------------------------------------------
---
--- Literal construction functions
---
----------------------------------------------------
-
-mkIntCLit :: Int -> CmmLit
-mkIntCLit i = CmmInt (toInteger i) wordRep
-
-zeroCLit :: CmmLit
-zeroCLit = CmmInt 0 wordRep
-
-mkLblExpr :: CLabel -> CmmExpr
-mkLblExpr lbl = CmmLit (CmmLabel lbl)
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