-cmmLiveness :: [CmmBasicBlock] -> BlockEntryLiveness
-cmmLiveness blocks =
- fixedpoint (cmmBlockDependants sources)
- (cmmBlockUpdate blocks')
- (map blockId blocks)
- (listToUFM [(blockId b, emptyUniqSet) | b <- blocks])
- where
- sources :: BlockSources
- sources = cmmBlockSources blocks
-
- blocks' :: BlockStmts
- blocks' = listToUFM $ map block_name blocks
-
- block_name :: CmmBasicBlock -> (BlockId, [CmmStmt])
- block_name b = (blockId b, blockStmts b)
-
-{-
--- For debugging, annotate each block with a comment indicating
--- the calculated live variables
-cmmLivenessComment ::
- BlockEnv (UniqSet LocalReg) -> CmmBasicBlock -> CmmBasicBlock
-cmmLivenessComment live (BasicBlock ident stmts) =
- BasicBlock ident stmts' where
- stmts' = (CmmComment $ mkFastString $ showSDoc $ ppr $ live'):stmts
- live' = map CmmLocal $ uniqSetToList $ lookupWithDefaultUFM live emptyUniqSet ident
--}
-
-
------------------------------------------------------------------------------
--- | Calculates a table of where one can lookup the blocks that might
--- need updating after a given block is updated in the liveness analysis
------------------------------------------------------------------------------
-cmmBlockSources :: [CmmBasicBlock] -> BlockSources
-cmmBlockSources blocks = foldr aux emptyUFM blocks
- where
- aux :: CmmBasicBlock
- -> BlockSources
- -> BlockSources
- aux block sourcesUFM =
- foldUniqSet (add_source_edges $ blockId block)
- sourcesUFM
- (branch_targets $ blockStmts block)
-
- add_source_edges :: BlockId -> BlockId
- -> BlockSources
- -> BlockSources
- add_source_edges source target ufm =
- addToUFM_Acc (flip addOneToUniqSet) unitUniqSet ufm target source
-
- branch_targets :: [CmmStmt] -> UniqSet BlockId
- branch_targets stmts =
- mkUniqSet $ concatMap target stmts where
- target (CmmBranch ident) = [ident]
- target (CmmCondBranch _ ident) = [ident]
- target (CmmSwitch _ blocks) = mapMaybe id blocks
- target _ = []
-
------------------------------------------------------------------------------
--- | Given the table calculated by 'cmmBlockSources', list all blocks
--- that depend on the result of a particular block.
---
--- Used by the call to 'fixedpoint'.
------------------------------------------------------------------------------
-cmmBlockDependants :: BlockSources -> BlockId -> [BlockId]
-cmmBlockDependants sources ident =
- uniqSetToList $ lookupWithDefaultUFM sources emptyUniqSet ident
-
------------------------------------------------------------------------------
--- | Given the table of type 'BlockStmts' and a block that was updated,
--- calculate an updated BlockEntryLiveness
------------------------------------------------------------------------------
-cmmBlockUpdate ::
- BlockStmts
- -> BlockId
- -> Maybe BlockId
- -> BlockEntryLiveness
- -> Maybe BlockEntryLiveness
-cmmBlockUpdate blocks node _ state =
- if (sizeUniqSet old_live) == (sizeUniqSet new_live)
- then Nothing
- else Just $ addToUFM state node new_live
- where
- new_live, old_live :: CmmLive
- new_live = cmmStmtListLive state block_stmts
- old_live = lookupWithDefaultUFM state missing_live node
-
- block_stmts :: [CmmStmt]
- block_stmts = lookupWithDefaultUFM blocks missing_block node
-
- missing_live = panic "unknown block id during liveness analysis"
- missing_block = panic "unknown block id during liveness analysis"
-
------------------------------------------------------------------------------
--- Section:
------------------------------------------------------------------------------
------------------------------------------------------------------------------
--- CmmBlockLive, cmmStmtListLive and helpers
------------------------------------------------------------------------------
-
--- Calculate the live registers for a local block (list of statements)
-
-cmmStmtListLive :: BlockEntryLiveness -> [CmmStmt] -> CmmLive
-cmmStmtListLive other_live stmts =
- foldr ((.) . (cmmStmtLive other_live)) id stmts emptyUniqSet
-
------------------------------------------------------------------------------
--- This code is written in the style of a state monad,
--- but since Control.Monad.State is not in the core
--- we can't use it in GHC, so we'll fake one here.
--- We don't need a return value so well leave it out.
--- Thus 'bind' reduces to function composition.
-
-type CmmLivenessTransformer = CmmLive -> CmmLive
-
--- Helpers for the "Monad"
-addLive, addKilled :: CmmLive -> CmmLivenessTransformer
-addLive new_live live = live `unionUniqSets` new_live
-addKilled new_killed live = live `minusUniqSet` new_killed
-
---------------------------------
--- Liveness of a CmmStmt
---------------------------------
-cmmHintFormalsToLiveLocals :: CmmHintFormals -> [LocalReg]
-cmmHintFormalsToLiveLocals formals = map fst formals
-
-cmmStmtLive :: BlockEntryLiveness -> CmmStmt -> CmmLivenessTransformer
-cmmStmtLive _ (CmmNop) = id
-cmmStmtLive _ (CmmComment _) = id
-cmmStmtLive _ (CmmAssign reg expr) =
- cmmExprLive expr . reg_liveness where
- reg_liveness =
- case reg of
- (CmmLocal reg') -> addKilled $ unitUniqSet reg'
- (CmmGlobal _) -> id
-cmmStmtLive _ (CmmStore expr1 expr2) =
- cmmExprLive expr2 . cmmExprLive expr1
-cmmStmtLive _ (CmmCall target results arguments _ _) =
- target_liveness .
- foldr ((.) . cmmExprLive) id (map fst arguments) .
- addKilled (mkUniqSet $ cmmHintFormalsToLiveLocals results) where
- target_liveness =
- case target of
- (CmmCallee target _) -> cmmExprLive target
- (CmmPrim _) -> id
-cmmStmtLive other_live (CmmBranch target) =
- addLive (lookupWithDefaultUFM other_live emptyUniqSet target)
-cmmStmtLive other_live (CmmCondBranch expr target) =
- cmmExprLive expr .
- addLive (lookupWithDefaultUFM other_live emptyUniqSet target)
-cmmStmtLive other_live (CmmSwitch expr targets) =
- cmmExprLive expr .
- (foldr ((.) . (addLive .
- lookupWithDefaultUFM other_live emptyUniqSet))
- id
- (mapCatMaybes id targets))
-cmmStmtLive _ (CmmJump expr params) =
- const (cmmExprLive expr $ foldr ((.) . cmmExprLive) id (map fst params) $ emptyUniqSet)
-cmmStmtLive _ (CmmReturn params) =
- const (foldr ((.) . cmmExprLive) id (map fst params) $ emptyUniqSet)
-
---------------------------------
--- Liveness of a CmmExpr
---------------------------------
-cmmExprLive :: CmmExpr -> CmmLivenessTransformer
-cmmExprLive expr = addLive (mkUniqSet $ expr_liveness expr) where
- expr_liveness :: CmmExpr -> [LocalReg]
- expr_liveness (CmmLit _) = []
- expr_liveness (CmmLoad expr _) = expr_liveness expr
- expr_liveness (CmmReg reg) = reg_liveness reg
- expr_liveness (CmmMachOp _ exprs) = concatMap expr_liveness exprs
- expr_liveness (CmmRegOff reg _) = reg_liveness reg