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| author | Ben.Lippmeier@anu.edu.au <unknown> | 2009-09-17 09:03:35 +0000 |
|---|---|---|
| committer | Ben.Lippmeier@anu.edu.au <unknown> | 2009-09-17 09:03:35 +0000 |
| commit | 028c032b60567b8cd501e9d7248e4aa86088a19b (patch) | |
| tree | beab9f04257cb5fcb5c28aac1b3921546ff28100 | |
| parent | 85981a6fc4bb94af433b0b3655c26c5ec4dda1bd (diff) | |
| download | haskell-028c032b60567b8cd501e9d7248e4aa86088a19b.tar.gz | |
NCG: Add sanity checking to linear allocator
If there are are unreachable basic blocks in the native code then the
linear allocator might loop. Detect this case and panic instead.
| -rw-r--r-- | compiler/nativeGen/RegAlloc/Linear/Main.hs | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/compiler/nativeGen/RegAlloc/Linear/Main.hs b/compiler/nativeGen/RegAlloc/Linear/Main.hs index 229fd32f57..0014eec2d4 100644 --- a/compiler/nativeGen/RegAlloc/Linear/Main.hs +++ b/compiler/nativeGen/RegAlloc/Linear/Main.hs @@ -190,7 +190,7 @@ linearRA_SCCs first_id block_live blocksAcc (AcyclicSCC block : sccs) linearRA_SCCs first_id block_live blocksAcc (CyclicSCC blocks : sccs) = do - blockss' <- process first_id block_live blocks [] (return []) + blockss' <- process first_id block_live blocks [] (return []) False linearRA_SCCs first_id block_live (reverse (concat blockss') ++ blocksAcc) sccs @@ -207,13 +207,21 @@ linearRA_SCCs first_id block_live blocksAcc (CyclicSCC blocks : sccs) more sanity checking to guard against this eventuality. -} -process _ _ [] [] accum +process _ _ [] [] accum _ = return $ reverse accum -process first_id block_live [] next_round accum - = process first_id block_live next_round [] accum +process first_id block_live [] next_round accum madeProgress + | not madeProgress + = pprPanic "RegAlloc.Linear.Main.process: no progress made, bailing out" + ( text "stalled blocks:" + $$ vcat (map ppr next_round)) + + | otherwise + = process first_id block_live + next_round [] accum False -process first_id block_live (b@(BasicBlock id _) : blocks) next_round accum +process first_id block_live (b@(BasicBlock id _) : blocks) + next_round accum madeProgress = do block_assig <- getBlockAssigR @@ -221,9 +229,11 @@ process first_id block_live (b@(BasicBlock id _) : blocks) next_round accum || id == first_id then do b' <- processBlock block_live b - process first_id block_live blocks next_round (b' : accum) + process first_id block_live blocks + next_round (b' : accum) True - else process first_id block_live blocks (b : next_round) accum + else process first_id block_live blocks + (b : next_round) accum madeProgress -- | Do register allocation on this basic block |