Add more disassembly infrastructure

macaw-ppc/macaw-ppc.cabal

@@ -28,6 +28,7 @@ library
   -- other-extensions:    
   build-depends:       base >=4.9 && <5,
                        containers,
+                       bytestring,
                        dismantle-ppc,
                        semmc,
                        semmc-ppc,

macaw-ppc/src/Data/Macaw/PPC/Disassemble.hs

@@ -1,5 +1,8 @@
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE UndecidableInstances #-}
 module Data.Macaw.PPC.Disassemble ( disassembleFn ) where
 
 import           Control.Lens ( (^.) )
@@ -7,39 +10,88 @@ import           Control.Monad ( unless )
 import qualified Control.Monad.Except as ET
 import           Control.Monad.ST ( ST )
 import           Control.Monad.Trans ( lift )
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy as LBS
 import qualified Data.Foldable as F
 import           Data.Word ( Word64 )
 
+import qualified Dismantle.PPC as D
+
 import           Data.Macaw.AbsDomain.AbsState as MA
 import           Data.Macaw.CFG
 import           Data.Macaw.CFG.Block
+import qualified Data.Macaw.CFG.Core as MC
 import qualified Data.Macaw.Memory as MM
+import qualified Data.Macaw.Memory.Permissions as MMP
 import qualified Data.Parameterized.Nonce as NC
 
 import           Data.Macaw.PPC.Generator
 
-newtype DisM s a = DisM { unDisM :: ET.ExceptT DisassembleException (ST s) a }
+newtype DisM ppc s a = DisM { unDisM :: ET.ExceptT (DisassembleException ppc) (ST s) a }
   deriving (Functor,
             Applicative,
             Monad,
-            ET.MonadError DisassembleException)
+            ET.MonadError (DisassembleException ppc))
 
-data DisassembleException = InvalidNextIP Word64 Word64
-  deriving (Show)
+data DisassembleException w = InvalidNextIP Word64 Word64
+                            | DecodeError (MM.MemoryError w)
 
-liftST :: ST s a -> DisM s a
+deriving instance (MM.MemWidth w) => Show (DisassembleException w)
+
+liftST :: ST s a -> DisM ppc s a
 liftST = DisM . lift
 
-tryDisassembleBlock :: (MM.MemWidth (RegAddrWidth (ArchReg ppc)))
+-- | Read one instruction from the 'MM.Memory' at the given segmented offset.
+--
+-- Returns the instruction and number of bytes consumed /or/ an error.
+readInstruction :: MM.Memory w
+                -> MM.MemSegmentOff w
+                -> Either (MM.MemoryError w) (D.Instruction, MM.MemWord w)
+readInstruction mem addr = MM.addrWidthClass (MM.memAddrWidth mem) $ do
+  let seg = MM.msegSegment addr
+  case MM.segmentFlags seg `MMP.hasPerm` MMP.execute of
+    False -> ET.throwError (MM.PermissionsError (MM.relativeSegmentAddr addr))
+    True -> do
+      contents <- MM.addrContentsAfter mem (MM.relativeSegmentAddr addr)
+      case contents of
+        [] -> ET.throwError (MM.AccessViolation (MM.relativeSegmentAddr addr))
+        MM.SymbolicRef {} : _ ->
+          ET.throwError (MM.UnexpectedRelocation (MM.relativeSegmentAddr addr))
+        MM.ByteRegion bs : _rest
+          | BS.null bs -> ET.throwError (MM.AccessViolation (MM.relativeSegmentAddr addr))
+          | otherwise -> do
+            let (bytesRead, minsn) = D.disassembleInstruction (LBS.fromStrict bs)
+            case minsn of
+              Just insn -> return (insn, fromIntegral bytesRead)
+              Nothing -> ET.throwError (MM.InvalidInstruction (MM.relativeSegmentAddr addr) contents)
+
+disassembleBlock :: (w ~ RegAddrWidth (ArchReg ppc))
+                 => MM.Memory (ArchAddrWidth ppc)
+                 -> GenState ppc w s ids
+                 -> MM.MemSegmentOff w
+                 -> MM.MemWord w
+                 -> DisM w s (MM.MemWord w, GenState ppc w s ids)
+disassembleBlock mem gs curIPAddr maxOffset = do
+  let seg = MM.msegSegment curIPAddr
+  let off = MM.msegOffset curIPAddr
+  case readInstruction mem curIPAddr of
+    Left err -> undefined
+    Right (i, bytesRead) -> do
+      -- let nextIP = MM.relativeAddr seg (off + bytesRead)
+      -- let nextIPVal = MC.RelocatableValue undefined nextIP
+      undefined
+
+tryDisassembleBlock :: (MM.MemWidth w,
+                       w ~ RegAddrWidth (ArchReg  ppc))
                     => MM.Memory (ArchAddrWidth ppc)
                     -> NC.NonceGenerator (ST s) s
                     -> ArchSegmentOff ppc
                     -> ArchAddrWord ppc
-                    -> DisM s ([Block ppc s], MM.MemWord (ArchAddrWidth ppc))
+                    -> DisM w s ([Block ppc s], MM.MemWord (ArchAddrWidth ppc))
 tryDisassembleBlock mem nonceGen startAddr maxSize = do
   let gs0 = initGenState nonceGen startAddr
   let startOffset = MM.msegOffset startAddr
-  (nextIPOffset, gs1) <- liftST $ runGenerator gs0 $ undefined
+  (nextIPOffset, gs1) <- disassembleBlock mem gs0 startAddr (startOffset + maxSize)
   unless (nextIPOffset > startOffset) $ do
     ET.throwError (InvalidNextIP (fromIntegral nextIPOffset) (fromIntegral startOffset))
   let blocks = F.toList (blockSeq gs1 ^. frontierBlocks)