emit' (INVOKESTATIC cpidx) = emitInvoke cpidx False
emit' (INVOKEINTERFACE cpidx _) = virtualCall cpidx True
emit' (INVOKEVIRTUAL cpidx) = virtualCall cpidx False
+
emit' (PUTSTATIC cpidx) = do
pop eax
trapaddr <- getCurrentOffset
mov eax (Addr 0x00000000) -- it's a trap
push eax
return $ Just (trapaddr, StaticField $ buildStaticFieldID cls cpidx)
+
+ emit' (GETFIELD x) = do
+ pop eax -- this pointer
+ trapaddr <- getCurrentOffset
+ -- like: 099db064 ff b0 e4 14 00 00 pushl 5348(%eax)
+ emit32 (0x9090ffff :: Word32); nop; nop
+ let patcher reip = do
+ let (cname, fname) = buildFieldOffset cls x
+ offset <- liftIO $ getFieldOffset cname fname
+ push32_rel_eax (Disp (fromIntegral offset)) -- get field
+ return reip
+ return $ Just (trapaddr, ObjectField patcher)
+ emit' (PUTFIELD x) = do
+ pop ebx -- value to write
+ pop eax -- this pointer
+ trapaddr <- getCurrentOffset
+ -- like: 4581fc6b 89 98 30 7b 00 00 movl %ebx,31536(%eax)
+ emit32 (0x9090ffff :: Word32); nop; nop
+ let patcher reip = do
+ let (cname, fname) = buildFieldOffset cls x
+ offset <- liftIO $ getFieldOffset cname fname
+ mov32_rel_ebx_eax (Disp (fromIntegral offset)) -- set field
+ return reip
+ return $ Just (trapaddr, ObjectField patcher)
+
emit' (INSTANCEOF cpidx) = do
pop eax
mov eax (Disp 0, eax) -- mtable of objectref
(CInteger i) -> liftIO $ return i
e -> error $ "LDCI... missing impl.: " ++ show e
push value
- emit (GETFIELD x) = do
- offset <- emitFieldOffset x
- push (Disp (fromIntegral offset), eax) -- get field
- emit (PUTFIELD x) = do
- pop ebx -- value to write
- offset <- emitFieldOffset x
- mov (Disp (fromIntegral offset), eax) ebx -- set field
emit IADD = do pop ebx; pop eax; add eax ebx; push eax
emit ISUB = do pop ebx; pop eax; sub eax ebx; push eax
emit IRETURN = do pop eax; emit RETURN
emit invalid = error $ "insn not implemented yet: " ++ show invalid
- -- TODO(bernhard): delay to runtime (find counter example!)
- emitFieldOffset :: Word16 -> CodeGen e s Int32
- emitFieldOffset x = do
- pop eax -- this pointer
- let (cname, fname) = buildFieldOffset cls x
- liftIO $ getFieldOffset cname fname
-
emitIF :: CMP -> CodeGen e s ()
emitIF cond = let
sid = case successor bb of TwoTarget _ t -> t; _ -> error "bad"
add esp (ptrSize :: Word32)
push eax
--- the regular push implementation, considers the provided immediate and selects
--- a different instruction if it fits in 8bit. but this is not useful for
--- patching.
+
+-- harpy tries to cut immediates (or displacements), if they fit in 8bit.
+-- however, this is bad for patching so we want to put always 32bit.
+
+-- push imm32
push32 :: Word32 -> CodeGen e s ()
push32 imm32 = emit8 0x68 >> emit32 imm32
+-- call disp32(%eax)
call32_eax :: Disp -> CodeGen e s ()
call32_eax (Disp disp32) = emit8 0xff >> emit8 0x90 >> emit32 disp32
+
+-- push disp32(%eax)
+push32_rel_eax :: Disp -> CodeGen e s ()
+push32_rel_eax (Disp disp32) = emit8 0xff >> emit8 0xb0 >> emit32 disp32
+
+-- mov %ebx, disp32(%eax)
+mov32_rel_ebx_eax :: Disp -> CodeGen e s ()
+mov32_rel_ebx_eax (Disp disp32) = emit8 0x89 >> emit8 0x98 >> emit32 disp32