code serialization, minimal opcodes

Test/TestByteCodeGenerator.hs

@@ -15,11 +15,12 @@ expectedClass = ClassFile {
             Utf8Info "java/lang/Object",
             Utf8Info "<init>",
             Utf8Info "()V",
-            ClassInfo 8,
+            Utf8Info "Code",
+            ClassInfo 9,
             Utf8Info "Testklasse"
         ],
         accessFlags = accessPublic,
-        thisClass = 7,
+        thisClass = 8,
         superClass = 1,
         fields = [],
         methods = [],
@@ -35,21 +36,22 @@ expectedClassWithFields = ClassFile {
             Utf8Info "java/lang/Object",
             Utf8Info "<init>",
             Utf8Info "()V",
-            ClassInfo 8,
+            Utf8Info "Code",
+            ClassInfo 9,
             Utf8Info "Testklasse",
-            FieldRefInfo (fromIntegral 7) (fromIntegral 10),
+            FieldRefInfo (fromIntegral 8) (fromIntegral 11),
-            NameAndTypeInfo (fromIntegral 11) (fromIntegral 12),
+            NameAndTypeInfo (fromIntegral 12) (fromIntegral 13),
             Utf8Info "testvariable",
             Utf8Info "I"
         ],
         accessFlags = accessPublic,
-        thisClass = 7,
+        thisClass = 8,
         superClass = 1,
         fields = [
             MemberInfo {
                 memberAccessFlags = accessPublic,
-                memberNameIndex = 11,
+                memberNameIndex = 12,
-                memberDescriptorIndex = 12,
+                memberDescriptorIndex = 13,
                 memberAttributes = []
             }
         ],

src/ByteCode/ClassFile.hs

@@ -22,7 +22,48 @@ data ConstantInfo = ClassInfo Word16
                   | Utf8Info [Char]
                   deriving (Show, Eq)
 
-data Attribute = Attribute Word16 [Word8] deriving (Show, Eq)
+
+{-
+    Code_attribute {
+    u2 attribute_name_index;
+    u4 attribute_length;
+    u2 max_stack;
+    u2 max_locals;
+    u4 code_length;
+    u1 code[code_length];
+    u2 exception_table_length;
+    {   u2 start_pc;
+        u2 end_pc;
+        u2 handler_pc;
+        u2 catch_type;
+    } exception_table[exception_table_length];
+    u2 attributes_count;
+    attribute_info attributes[attributes_count];
+-}
+--data Attribute = Attribute Word16 [Word8] deriving (Show, Eq)
+data Operation = Iadd
+               | Isub
+               | Imul
+               | Idiv
+               | Return
+               | IReturn
+               | Sipush Word16
+               | Ldc_w Word16
+               | Aload Word16
+               | Iload Word16
+               | Astore Word16
+               | Istore Word16
+               | Putfield Word16
+               | GetField Word16
+    deriving (Show, Eq)
+
+
+data Attribute = CodeAttribute {
+    attributeMaxStack   :: Word16,
+    attributeMaxLocals  :: Word16,
+    attributeCode       :: [Operation]
+} deriving (Show, Eq)
+
 
 data MemberInfo = MemberInfo {
     memberAccessFlags     :: Word16,
@@ -72,8 +113,36 @@ instance Serializable MemberInfo where
                     ++ unpackWord16 (fromIntegral (length (memberAttributes member)))
                     ++ concatMap serialize (memberAttributes member)
 
+instance Serializable Operation where
+    serialize Iadd              = [0x60]
+    serialize Isub              = [0x64]
+    serialize Imul              = [0x68]
+    serialize Idiv              = [0x6C]
+    serialize Return            = [0xB1]
+    serialize IReturn           = [0xAC]
+    serialize (Sipush index)    = 0x11 : unpackWord16 index
+    serialize (Ldc_w index)     = 0x13 : unpackWord16 index
+    serialize (Aload index)     = [0xC4, 0x19] ++ unpackWord16 index
+    serialize (Iload index)     = [0xC4, 0x15] ++ unpackWord16 index
+    serialize (Astore index)    = [0xC4, 0x3A] ++ unpackWord16 index
+    serialize (Istore index)    = [0xC4, 0x36] ++ unpackWord16 index
+    serialize (Putfield index)  = 0xB5 : unpackWord16 index
+    serialize (GetField index)  = 0xB4 : unpackWord16 index
+
 instance Serializable Attribute where
-    serialize (Attribute nameIndex bytes) = unpackWord16 nameIndex ++ unpackWord32 (fromIntegral (length bytes)) ++ bytes
+    serialize (CodeAttribute { attributeMaxStack = maxStack,
+                               attributeMaxLocals = maxLocals,
+                               attributeCode = code }) = let
+            assembledCode = concat (map serialize code)
+        in
+            unpackWord16 7                                                  -- attribute_name_index
+            ++ unpackWord32 (12 + (fromIntegral (length assembledCode)))    -- attribute_length
+            ++ unpackWord16 maxStack                                        -- max_stack
+            ++ unpackWord16 maxLocals                                       -- max_locals
+            ++ unpackWord32 (fromIntegral (length assembledCode))           -- code_length
+            ++ assembledCode                                                -- code
+            ++ unpackWord16 0                                               -- exception_table_length
+            ++ unpackWord16 0                                               -- attributes_count
 
 instance Serializable ClassFile where
     serialize classfile  = unpackWord32 0xC0FEBABE                                           -- magic

src/ByteCode/ClassFile/Generator.hs

@@ -15,7 +15,7 @@ datatypeDescriptor :: String -> String
 datatypeDescriptor "int" = "I"
 datatypeDescriptor "char" = "C"
 datatypeDescriptor "boolean" = "B"
-datatypeDescriptor x = x
+datatypeDescriptor x = "L" ++ x
 
 
 classBuilder :: ClassFileBuilder Class
@@ -26,13 +26,14 @@ classBuilder (Class name methods fields) _ = let
             NameAndTypeInfo 5 6,
             Utf8Info "java/lang/Object",
             Utf8Info "<init>",
-            Utf8Info "()V"
+            Utf8Info "()V",
+            Utf8Info "Code"
             ]
-        nameConstants = [ClassInfo 8, Utf8Info name]
+        nameConstants = [ClassInfo 9, Utf8Info name]
         nakedClassFile = ClassFile {
             constantPool = baseConstants ++ nameConstants,
             accessFlags = accessPublic,
-            thisClass = 7,
+            thisClass = 8,
             superClass = 1,
             fields = [],
             methods = [],