.gitignore

@@ -8,7 +8,6 @@ cabal-dev
 *.chs.h
 *.dyn_o
 *.dyn_hi
-*.java
 *.class
 *.local~*
 src/Parser/JavaParser.hs

Test/JavaSources/Main.java

@@ -0,0 +1,38 @@
+// compile all test files using:
+// ls Test/JavaSources/*.java | grep -v ".*Main.java" | xargs -I {} cabal run compiler {}
+// compile (in project root) using:
+// javac -g:none -sourcepath Test/JavaSources/ Test/JavaSources/Main.java 
+// afterwards, run using
+// java -ea -cp Test/JavaSources/ Main
+
+public class Main {
+    public static void main(String[] args)
+    {
+        TestEmpty empty = new TestEmpty();
+        TestFields fields = new TestFields();
+        TestConstructor constructor = new TestConstructor(42);
+        TestMultipleClasses multipleClasses = new TestMultipleClasses();
+        TestRecursion recursion = new TestRecursion(10);
+        TestMalicious malicious = new TestMalicious();
+
+        // constructing a basic class works
+        assert empty != null;
+        // initializers (and default initializers to 0/null) work
+        assert fields.a == 0 && fields.b == 42;
+        // constructor parameters override initializers
+        assert constructor.a == 42;
+        // multiple classes within one file work. Referencing another classes fields/methods works.
+        assert multipleClasses.a.a == 42;
+        // self-referencing classes work.
+        assert recursion.child.child.child.child.child.value == 5;
+        // self-referencing methods work.
+        assert recursion.fibonacci(15) == 610;
+        // intentionally dodgy expressions work
+        assert malicious.assignNegativeIncrement(42) == -42;
+        assert malicious.tripleAddition(1, 2, 3) == 6;
+        for(int i = 0; i < 3; i++)
+        {
+            assert malicious.cursedFormatting(i) == i;
+        }
+    }
+}

Test/JavaSources/TestConstructor.java

@@ -0,0 +1,9 @@
+public class TestConstructor
+{
+    public int a = -1;
+
+    public TestConstructor(int initial_value)
+    {
+        a = initial_value;
+    }
+}

Test/JavaSources/TestEmpty.java

@@ -0,0 +1,4 @@
+public class TestEmpty
+{
+    
+}

Test/JavaSources/TestFields.java

@@ -0,0 +1,5 @@
+public class TestFields
+{
+    public int a;
+    public int b = 42;
+}

Test/JavaSources/TestMalicious.java

@@ -0,0 +1,41 @@
+public class TestMalicious {
+    public int assignNegativeIncrement(int n)
+    {
+        return n=-++n+1;
+    }
+
+    public int tripleAddition(int a, int b, int c)
+    {
+        return a+++b+++c++;
+    }
+
+    public int cursedFormatting(int n)
+    {
+        if
+        
+        
+        (n == 0)
+        
+        {
+            
+            return                      ((((0))));
+        }
+
+        else 
+
+        
+        if(n == 
+        
+        1)
+                    {
+            return 
+            
+            
+            1;
+                    }else                 {
+            return 
+            2
+            ;
+                    }
+    }
+}

Test/JavaSources/TestMultipleClasses.java

@@ -0,0 +1,9 @@
+public class TestMultipleClasses
+{
+    public AnotherTestClass a = new AnotherTestClass();
+}
+
+class AnotherTestClass
+{
+    public int a = 42;
+}

Test/JavaSources/TestRecursion.java

@@ -0,0 +1,27 @@
+public class TestRecursion {
+
+    public int value = 0;
+    public TestRecursion child = null;
+
+    public TestRecursion(int n)
+    {
+        value = n;
+
+        if(n > 0)
+        {
+            child = new TestRecursion(n - 1);
+        }
+    }
+
+    public int fibonacci(int n)
+    {
+        if(n < 2)
+        {
+            return n;
+        }
+        else
+        {
+            return fibonacci(n - 1) + this.fibonacci(n - 2);
+        }
+    }    
+}

Test/TestByteCodeGenerator.hs

@@ -1,118 +0,0 @@
-module TestByteCodeGenerator where
-
-import Test.HUnit
-import ByteCode.ClassFile.Generator
-import ByteCode.ClassFile
-import ByteCode.Constants
-import Ast
-
-nakedClass = Class "Testklasse" [] []
-expectedClass = ClassFile {
-        constantPool = [
-            ClassInfo 4,
-            MethodRefInfo 1 3,
-            NameAndTypeInfo 5 6,
-            Utf8Info "java/lang/Object",
-            Utf8Info "<init>",
-            Utf8Info "()V",
-            Utf8Info "Code",
-            ClassInfo 9,
-            Utf8Info "Testklasse"
-        ],
-        accessFlags = accessPublic,
-        thisClass = 8,
-        superClass = 1,
-        fields = [],
-        methods = [],
-        attributes = []
-    }
-
-classWithFields = Class "Testklasse" [] [VariableDeclaration "int" "testvariable" Nothing]
-expectedClassWithFields = ClassFile {
-        constantPool = [
-            ClassInfo 4,
-            MethodRefInfo 1 3,
-            NameAndTypeInfo 5 6,
-            Utf8Info "java/lang/Object",
-            Utf8Info "<init>",
-            Utf8Info "()V",
-            Utf8Info "Code",
-            ClassInfo 9,
-            Utf8Info "Testklasse",
-            FieldRefInfo 8 11,
-            NameAndTypeInfo 12 13,
-            Utf8Info "testvariable",
-            Utf8Info "I"
-        ],
-        accessFlags = accessPublic,
-        thisClass = 8,
-        superClass = 1,
-        fields = [
-            MemberInfo {
-                memberAccessFlags = accessPublic,
-                memberNameIndex = 12,
-                memberDescriptorIndex = 13,
-                memberAttributes = []
-            }
-        ],
-        methods = [],
-        attributes = []
-    }
-
-method = MethodDeclaration "int" "add_two_numbers" [
-    ParameterDeclaration "int" "a",
-    ParameterDeclaration "int" "b" ]
-    (Block [Return (Just (BinaryOperation Addition (Reference "a") (Reference "b")))])
-
-
-classWithMethod = Class "Testklasse" [method] []
-expectedClassWithMethod = ClassFile {
-        constantPool = [
-            ClassInfo 4,
-            MethodRefInfo 1 3,
-            NameAndTypeInfo 5 6,
-            Utf8Info "java/lang/Object",
-            Utf8Info "<init>",
-            Utf8Info "()V",
-            Utf8Info "Code",
-            ClassInfo 9,
-            Utf8Info "Testklasse",
-            FieldRefInfo 8 11,
-            NameAndTypeInfo 12 13,
-            Utf8Info "add_two_numbers",
-            Utf8Info "(II)I"
-        ],
-        accessFlags = accessPublic,
-        thisClass = 8,
-        superClass = 1,
-        fields = [],
-        methods = [
-            MemberInfo {
-                memberAccessFlags = accessPublic,
-                memberNameIndex = 12,
-                memberDescriptorIndex = 13,
-                memberAttributes = [
-                    CodeAttribute {
-                        attributeMaxStack = 420,
-                        attributeMaxLocals = 420,
-                        attributeCode = [Opiadd]
-                    }
-                ]
-            }
-        ],
-        attributes = []
-    }
-
-testBasicConstantPool = TestCase $ assertEqual "basic constant pool" expectedClass $ classBuilder nakedClass emptyClassFile
-testFields = TestCase $ assertEqual "fields in constant pool" expectedClassWithFields $ classBuilder classWithFields emptyClassFile
-testMethodDescriptor = TestCase $ assertEqual "method descriptor" "(II)I" (methodDescriptor method)
-testMethodAssembly = TestCase $ assertEqual "method assembly" expectedClassWithMethod (classBuilder classWithMethod emptyClassFile)
-testFindMethodIndex = TestCase $ assertEqual "find method" (Just 0) (findMethodIndex expectedClassWithMethod "add_two_numbers")
-
-tests = TestList [
-    TestLabel "Basic constant pool" testBasicConstantPool,
-    TestLabel "Fields constant pool" testFields,
-    TestLabel "Method descriptor building" testMethodDescriptor,
-    TestLabel "Method assembly" testMethodAssembly,
-    TestLabel "Find method by name" testFindMethodIndex
-    ]

Test/TestSuite.hs

@@ -2,13 +2,11 @@ module Main where
 
 import Test.HUnit
 import TestLexer
-import TestByteCodeGenerator
 import TestParser
 
-
 tests = TestList [
-    TestLabel "TestLexer" TestLexer.tests,
-    TestLabel "TestParser" TestParser.tests,
-    TestLabel "TestByteCodeGenerator" TestByteCodeGenerator.tests]
+        TestLabel "TestLexer" TestLexer.tests,
+        TestLabel "TestParser" TestParser.tests
+    ]
 
 main = do runTestTTAndExit Main.tests

project.cabal

@@ -10,7 +10,8 @@ executable compiler
                         array,
                         HUnit,
                         utf8-string,
-                        bytestring
+                        bytestring,
+                        filepath
     default-language:   Haskell2010
     hs-source-dirs:     src
     build-tool-depends: alex:alex, happy:happy
@@ -19,14 +20,11 @@ executable compiler
                         Ast,
                         Example,
                         Typecheck,
+                        ByteCode.Util,
                         ByteCode.ByteUtil,
                         ByteCode.ClassFile,
-                        ByteCode.Generation.Generator,
-                        ByteCode.Generation.Assembler.ExpressionAndStatement,
-                        ByteCode.Generation.Assembler.Method,
-                        ByteCode.Generation.Builder.Class,
-                        ByteCode.Generation.Builder.Field,
-                        ByteCode.Generation.Builder.Method,
+                        ByteCode.Assembler,
+                        ByteCode.Builder,
                         ByteCode.Constants
 
 test-suite tests
@@ -37,15 +35,17 @@ test-suite tests
                         array,
                         HUnit,
                         utf8-string,
-                        bytestring
+                        bytestring,
+                        filepath
     build-tool-depends: alex:alex, happy:happy
     other-modules:      Parser.Lexer,
                         Parser.JavaParser,
                         Ast,
                         TestLexer,
                         TestParser,
-                        TestByteCodeGenerator,
+                        ByteCode.Util,
                         ByteCode.ByteUtil,
                         ByteCode.ClassFile,
-                        ByteCode.ClassFile.Generator,
+                        ByteCode.Assembler,
+                        ByteCode.Builder,
                         ByteCode.Constants

src/ByteCode/Assembler.hs

@@ -0,0 +1,276 @@
+module ByteCode.Assembler where
+
+import ByteCode.Constants
+import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Util
+import Ast
+import Data.Char
+import Data.List
+import Data.Word
+
+type Assembler a = ([ConstantInfo], [Operation], [String]) -> a -> ([ConstantInfo], [Operation], [String])
+
+assembleExpression :: Assembler Expression
+assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation op a b))
+    | elem op [Addition, Subtraction, Multiplication, Division, Modulo, BitwiseAnd, BitwiseOr, BitwiseXor, And, Or] = let
+            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
+            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
+        in
+            (bConstants, bOps ++ [binaryOperation op], lvars)
+    | elem op [CompareEqual, CompareNotEqual, CompareLessThan, CompareLessOrEqual, CompareGreaterThan, CompareGreaterOrEqual] = let
+            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
+            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
+            cmp_op = comparisonOperation op 9
+            cmp_ops = [cmp_op, Opsipush 0, Opgoto 6, Opsipush 1]
+        in
+            (bConstants, bOps ++ cmp_ops, lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation NameResolution (TypedExpression atype a) (TypedExpression btype (FieldVariable b)))) = let
+        (fConstants, fieldIndex) = getFieldIndex constants (atype, b, datatypeDescriptor btype)
+        (aConstants, aOps, _) = assembleExpression (fConstants, ops, lvars) (TypedExpression atype a)
+    in
+        (aConstants, aOps ++ [Opgetfield (fromIntegral fieldIndex)], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (CharacterLiteral literal)) =
+    (constants, ops ++ [Opsipush (fromIntegral (ord literal))], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (BooleanLiteral literal)) =
+    (constants, ops ++ [Opsipush (if literal then 1 else 0)], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (IntegerLiteral literal))
+    | literal <= 32767 && literal >= -32768 = (constants, ops ++ [Opsipush (fromIntegral literal)], lvars)
+    | otherwise = (constants ++ [IntegerInfo (fromIntegral literal)], ops ++ [Opldc_w (fromIntegral (1 + length constants))], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ NullLiteral) =
+    (constants, ops ++ [Opaconst_null], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression etype (UnaryOperation Not expr)) = let
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        newConstant = fromIntegral (1 + length exprConstants)
+    in case etype of
+        "int" -> (exprConstants ++ [IntegerInfo 0x7FFFFFFF], exprOps ++ [Opldc_w newConstant, Opixor], lvars)
+        "char" -> (exprConstants, exprOps ++ [Opsipush 0xFFFF, Opixor], lvars)
+        "boolean" -> (exprConstants, exprOps ++ [Opsipush 0x01, Opixor], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (UnaryOperation Minus expr)) = let
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+    in
+        (exprConstants, exprOps ++ [Opineg], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression dtype (LocalVariable name))
+    | name == "this" = (constants, ops ++ [Opaload 0], lvars)
+    | otherwise = let
+            localIndex = findIndex ((==) name) lvars
+            isPrimitive = elem dtype ["char", "boolean", "int"]
+        in case localIndex of
+            Just index -> (constants, ops ++ if isPrimitive then [Opiload (fromIntegral index)] else [Opaload (fromIntegral index)], lvars)
+            Nothing -> error ("No such local variable found in local variable pool: " ++ name)
+
+assembleExpression (constants, ops, lvars) (TypedExpression dtype (StatementExpressionExpression stmtexp)) =
+        assembleStatementExpression (constants, ops, lvars) stmtexp
+
+assembleExpression _ expr = error ("unimplemented: " ++ show expr)
+
+assembleNameChain :: Assembler Expression
+assembleNameChain input (TypedExpression _ (BinaryOperation NameResolution (TypedExpression atype a) (TypedExpression _ (FieldVariable _)))) =
+        assembleExpression input (TypedExpression atype a)
+assembleNameChain input expr = assembleExpression input expr
+
+
+assembleStatementExpression :: Assembler StatementExpression
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (Assignment (TypedExpression dtype receiver) expr)) = let
+        target = resolveNameChain (TypedExpression dtype receiver)
+    in case target of
+        (TypedExpression dtype (LocalVariable name)) -> let
+                localIndex = findIndex ((==) name) lvars
+                (constants_a, ops_a, _) = assembleExpression (constants, ops, lvars) expr
+                isPrimitive = elem dtype ["char", "boolean", "int"]
+            in case localIndex of
+                Just index -> (constants_a, ops_a ++ if isPrimitive then [Opdup, Opistore (fromIntegral index)] else [Opastore (fromIntegral index)], lvars)
+                Nothing -> error ("No such local variable found in local variable pool: " ++ name)
+        (TypedExpression dtype (FieldVariable name)) -> let
+                owner = resolveNameChainOwner (TypedExpression dtype receiver)
+            in case owner of
+                (TypedExpression otype _) -> let
+                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
+                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
+                        (constants_a, ops_a, _) = assembleExpression (constants_r, ops_r, lvars) expr
+                    in
+                        (constants_a, ops_a ++ [Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
+                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype receiver))) = let
+        target = resolveNameChain (TypedExpression dtype receiver)
+    in case target of
+        (TypedExpression dtype (LocalVariable name)) -> let 
+                localIndex = findIndex ((==) name) lvars
+                expr = (TypedExpression dtype (LocalVariable name))
+                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+            in case localIndex of
+                Just index -> (exprConstants, exprOps ++ [Opsipush 1, Opiadd, Opdup, Opistore (fromIntegral index)], lvars)
+                Nothing -> error("No such local variable found in local variable pool: " ++ name)
+        (TypedExpression dtype (FieldVariable name)) -> let
+                owner = resolveNameChainOwner (TypedExpression dtype receiver)
+            in case owner of
+                (TypedExpression otype _) -> let
+                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
+                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
+                    in
+                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opsipush 1, Opiadd, Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
+                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype receiver))) = let
+        target = resolveNameChain (TypedExpression dtype receiver)
+    in case target of
+        (TypedExpression dtype (LocalVariable name)) -> let 
+                localIndex = findIndex ((==) name) lvars
+                expr = (TypedExpression dtype (LocalVariable name))
+                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+            in case localIndex of
+                Just index -> (exprConstants, exprOps ++ [Opsipush 1, Opisub, Opdup, Opistore (fromIntegral index)], lvars)
+                Nothing -> error("No such local variable found in local variable pool: " ++ name)
+        (TypedExpression dtype (FieldVariable name)) -> let
+                owner = resolveNameChainOwner (TypedExpression dtype receiver)
+            in case owner of
+                (TypedExpression otype _) -> let
+                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
+                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
+                    in
+                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opsipush 1, Opisub, Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
+                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype receiver))) = let
+        target = resolveNameChain (TypedExpression dtype receiver)
+    in case target of
+        (TypedExpression dtype (LocalVariable name)) -> let 
+                localIndex = findIndex ((==) name) lvars
+                expr = (TypedExpression dtype (LocalVariable name))
+                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+            in case localIndex of
+                Just index -> (exprConstants, exprOps ++ [Opdup, Opsipush 1, Opiadd, Opistore (fromIntegral index)], lvars)
+                Nothing -> error("No such local variable found in local variable pool: " ++ name)
+        (TypedExpression dtype (FieldVariable name)) -> let
+                owner = resolveNameChainOwner (TypedExpression dtype receiver)
+            in case owner of
+                (TypedExpression otype _) -> let
+                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
+                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
+                    in
+                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opdup_x1, Opsipush 1, Opiadd, Opputfield (fromIntegral fieldIndex)], lvars)
+                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype receiver))) = let
+        target = resolveNameChain (TypedExpression dtype receiver)
+    in case target of
+        (TypedExpression dtype (LocalVariable name)) -> let 
+                localIndex = findIndex ((==) name) lvars
+                expr = (TypedExpression dtype (LocalVariable name))
+                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+            in case localIndex of
+                Just index -> (exprConstants, exprOps ++ [Opdup, Opsipush 1, Opisub, Opistore (fromIntegral index)], lvars)
+                Nothing -> error("No such local variable found in local variable pool: " ++ name)
+        (TypedExpression dtype (FieldVariable name)) -> let
+                owner = resolveNameChainOwner (TypedExpression dtype receiver)
+            in case owner of
+                (TypedExpression otype _) -> let
+                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
+                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
+                    in
+                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opdup_x1, Opsipush 1, Opisub, Opputfield (fromIntegral fieldIndex)], lvars)
+                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression rtype (MethodCall (TypedExpression otype receiver) name params)) = let
+        (constants_r, ops_r, lvars_r) = assembleExpression (constants, ops, lvars) (TypedExpression otype receiver)
+        (constants_p, ops_p, lvars_p) = foldl assembleExpression (constants_r, ops_r, lvars_r) params
+        (constants_m, methodIndex) = getMethodIndex constants_p (otype, name, methodDescriptorFromParamlist params rtype)
+    in
+        (constants_m, ops_p ++ [Opinvokevirtual (fromIntegral methodIndex)], lvars_p)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression rtype (ConstructorCall name params)) = let
+        (constants_c, classIndex) = getClassIndex constants name
+        (constants_p, ops_p, lvars_p) = foldl assembleExpression (constants_c, ops ++ [Opnew (fromIntegral classIndex), Opdup], lvars) params
+        (constants_m, methodIndex) = getMethodIndex constants_p (name, "<init>", methodDescriptorFromParamlist params "void")
+    in
+        (constants_m, ops_p ++ [Opinvokespecial (fromIntegral methodIndex)], lvars_p)
+
+
+assembleStatement :: Assembler Statement
+assembleStatement (constants, ops, lvars) (TypedStatement stype (Return expr)) = case expr of
+    Nothing -> (constants, ops ++ [Opreturn], lvars)
+    Just expr -> let
+            (expr_constants, expr_ops, _) = assembleExpression (constants, ops, lvars) expr
+        in
+            (expr_constants, expr_ops ++ [returnOperation stype], lvars)
+
+assembleStatement (constants, ops, lvars) (TypedStatement _ (Block statements)) =
+    foldl assembleStatement (constants, ops, lvars) statements
+
+assembleStatement (constants, ops, lvars) (TypedStatement dtype (If expr if_stmt else_stmt)) = let
+        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
+        (constants_ifa, ops_ifa, _) = assembleStatement (constants_cmp, [], lvars) if_stmt
+        (constants_elsea, ops_elsea, _) = case else_stmt of
+            Nothing -> (constants_ifa, [], lvars)
+            Just stmt -> assembleStatement (constants_ifa, [], lvars) stmt
+        -- +6 because we insert 2 gotos, one for if, one for else
+        if_length = sum (map opcodeEncodingLength ops_ifa)
+        -- +3 because we need to account for the goto in the if statement.
+        else_length = sum (map opcodeEncodingLength ops_elsea)
+    in case dtype of
+        "void" -> (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq (if_length + 6)] ++ ops_ifa ++ [Opgoto (else_length + 3)] ++ ops_elsea, lvars)
+        otherwise -> (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq (if_length + 3)] ++ ops_ifa ++ ops_elsea, lvars)
+
+assembleStatement (constants, ops, lvars) (TypedStatement _ (While expr stmt)) = let
+        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
+        (constants_stmta, ops_stmta, _) = assembleStatement (constants_cmp, [], lvars) stmt
+        -- +3 because we insert 2 gotos, one for the comparison, one for the goto back to the comparison
+        stmt_length = sum (map opcodeEncodingLength ops_stmta) + 6
+        entire_length = stmt_length + sum (map opcodeEncodingLength ops_cmp)
+    in
+        (constants_stmta, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq stmt_length] ++ ops_stmta ++ [Opgoto (-entire_length)], lvars)
+
+assembleStatement (constants, ops, lvars) (TypedStatement _ (LocalVariableDeclaration (VariableDeclaration dtype name expr))) = let
+        isPrimitive = elem dtype ["char", "boolean", "int"]
+        (constants_init, ops_init, _) = case expr of
+            Just exp -> assembleExpression (constants, ops, lvars) exp
+            Nothing -> (constants, ops ++ if isPrimitive then [Opsipush 0] else [Opaconst_null], lvars)
+        localIndex = fromIntegral (length lvars)
+        storeLocal = if isPrimitive then [Opistore localIndex] else [Opastore localIndex]
+    in
+        (constants_init, ops_init ++ storeLocal, lvars ++ [name])
+
+assembleStatement (constants, ops, lvars) (TypedStatement _ (StatementExpressionStatement expr)) = let
+        (constants_e, ops_e, lvars_e) = assembleStatementExpression (constants, ops, lvars) expr
+    in
+        (constants_e, ops_e ++ [Oppop], lvars_e)
+
+assembleStatement _ stmt = error ("Not yet implemented: " ++ show stmt)
+
+
+assembleMethod :: Assembler MethodDeclaration
+assembleMethod (constants, ops, lvars) (MethodDeclaration returntype name _ (TypedStatement _ (Block statements)))
+    | name == "<init>"  = let
+            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
+            init_ops = [Opaload 0, Opinvokespecial 2]
+        in
+            (constants_a, init_ops ++ ops_a ++ [Opreturn], lvars_a)
+    | otherwise = case returntype of
+        "void" -> let
+                (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
+            in
+                (constants_a, ops_a ++ [Opreturn], lvars_a)
+        otherwise -> foldl assembleStatement (constants, ops, lvars) statements
+assembleMethod _ (MethodDeclaration _ _ _ stmt) = error ("Typed block expected for method body, got: " ++ show stmt) 

src/ByteCode/Builder.hs

@@ -0,0 +1,117 @@
+module ByteCode.Builder where
+
+import ByteCode.Constants
+import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Assembler
+import ByteCode.Util
+import Ast
+import Data.Char
+import Data.List
+import Data.Word
+
+type ClassFileBuilder a = a -> ClassFile -> ClassFile
+
+fieldBuilder :: ClassFileBuilder VariableDeclaration
+fieldBuilder (VariableDeclaration datatype name _) input = let
+        baseIndex = 1 + length (constantPool input)
+        constants = [
+                FieldRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
+                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
+                Utf8Info name,
+                Utf8Info (datatypeDescriptor datatype)
+            ]
+        field = MemberInfo {
+            memberAccessFlags = accessPublic,
+            memberNameIndex = (fromIntegral (baseIndex + 2)),
+            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
+            memberAttributes = []
+            }
+    in
+        input {
+            constantPool = (constantPool input) ++ constants,
+            fields = (fields input) ++ [field]
+        }
+
+
+
+methodBuilder :: ClassFileBuilder MethodDeclaration
+methodBuilder (MethodDeclaration returntype name parameters statement) input = let
+        baseIndex = 1 + length (constantPool input)
+        constants = [
+                MethodRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
+                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
+                Utf8Info name,
+                Utf8Info (methodDescriptor (MethodDeclaration returntype name parameters (Block [])))
+            ]
+
+        method = MemberInfo {
+            memberAccessFlags = accessPublic,
+            memberNameIndex = (fromIntegral (baseIndex + 2)),
+            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
+            memberAttributes = []
+            }
+    in 
+        input {
+            constantPool = (constantPool input) ++ constants,
+            methods = (methods input) ++ [method]
+        }
+        
+
+
+methodAssembler :: ClassFileBuilder MethodDeclaration
+methodAssembler (MethodDeclaration returntype name parameters statement) input = let
+        methodConstantIndex = findMethodIndex input name
+    in case methodConstantIndex of
+        Nothing -> error ("Cannot find method entry in method pool for method: " ++ name)
+        Just index -> let
+                declaration = MethodDeclaration returntype name parameters statement
+                paramNames = "this" : [name | ParameterDeclaration _ name <- parameters]
+            in case (splitAt index (methods input)) of
+                (pre, []) -> input
+                (pre, method : post) -> let
+                        (_, bytecode, _) = assembleMethod (constantPool input, [], paramNames) declaration
+                        assembledMethod = method {
+                            memberAttributes = [
+                                CodeAttribute {
+                                    attributeMaxStack = 420,
+                                    attributeMaxLocals = 420,
+                                    attributeCode = bytecode
+                                }
+                            ]
+                        }
+                    in
+                        input {
+                            methods = pre ++ (assembledMethod : post)
+                        }
+
+
+classBuilder :: ClassFileBuilder Class
+classBuilder (Class name methods fields) _ = let
+        baseConstants = [
+            ClassInfo 4,
+            MethodRefInfo 1 3,
+            NameAndTypeInfo 5 6,
+            Utf8Info "java/lang/Object",
+            Utf8Info "<init>",
+            Utf8Info "()V",
+            Utf8Info "Code"
+            ]
+        nameConstants = [ClassInfo 9, Utf8Info name]
+        nakedClassFile = ClassFile {
+            constantPool = baseConstants ++ nameConstants,
+            accessFlags = accessPublic,
+            thisClass = 8,
+            superClass = 1,
+            fields = [],
+            methods = [],
+            attributes = []
+        }
+
+        methodsWithInjectedConstructor = injectDefaultConstructor methods
+        methodsWithInjectedInitializers = injectFieldInitializers name fields methodsWithInjectedConstructor
+
+        classFileWithFields = foldr fieldBuilder nakedClassFile fields
+        classFileWithMethods = foldr methodBuilder classFileWithFields methodsWithInjectedInitializers
+        classFileWithAssembledMethods = foldr methodAssembler classFileWithMethods methodsWithInjectedInitializers
+    in
+        classFileWithAssembledMethods

src/ByteCode/ByteUtil.hs

@@ -1,7 +1,6 @@
-module ByteCode.ByteUtil(unpackWord16, unpackWord32) where
+module ByteCode.ByteUtil where
 
 import Data.Word ( Word8, Word16, Word32 )
-import Data.Int
 import Data.Bits
 
 unpackWord16 :: Word16 -> [Word8]

src/ByteCode/ClassFile.hs

@@ -6,15 +6,16 @@ module ByteCode.ClassFile(
     Operation(..),
     serialize,
     emptyClassFile,
-    opcodeEncodingLength
+    opcodeEncodingLength,
+    className
 ) where
 
 import Data.Word
 import Data.Int
 import Data.ByteString (unpack)
 import Data.ByteString.UTF8 (fromString)
-import ByteCode.ByteUtil
 import ByteCode.Constants
+import ByteCode.ByteUtil
 
 data ConstantInfo = ClassInfo Word16
                   | FieldRefInfo Word16 Word16
@@ -28,11 +29,13 @@ data Operation = Opiadd
                | Opisub
                | Opimul
                | Opidiv
+               | Opirem
                | Opiand
                | Opior
                | Opixor
                | Opineg
                | Opdup
+               | Opnew Word16
                | Opif_icmplt Word16
                | Opif_icmple Word16
                | Opif_icmpgt Word16
@@ -43,7 +46,10 @@ data Operation = Opiadd
                | Opreturn
                | Opireturn
                | Opareturn
+               | Opdup_x1
+               | Oppop
                | Opinvokespecial Word16
+               | Opinvokevirtual Word16
                | Opgoto Word16
                | Opsipush Word16
                | Opldc_w Word16
@@ -91,16 +97,26 @@ emptyClassFile = ClassFile {
         attributes = []
     }
 
+className :: ClassFile -> String
+className classFile = let
+        classInfo = (constantPool classFile)!!(fromIntegral (thisClass classFile))
+    in case classInfo of
+        Utf8Info className -> className
+        otherwise -> error ("expected Utf8Info but got: " ++ show otherwise)
+        
+
 opcodeEncodingLength :: Operation -> Word16
 opcodeEncodingLength Opiadd                 = 1
 opcodeEncodingLength Opisub                 = 1
 opcodeEncodingLength Opimul                 = 1
 opcodeEncodingLength Opidiv                 = 1
+opcodeEncodingLength Opirem                 = 1
 opcodeEncodingLength Opiand                 = 1
 opcodeEncodingLength Opior                  = 1
 opcodeEncodingLength Opixor                 = 1
 opcodeEncodingLength Opineg                 = 1
 opcodeEncodingLength Opdup                  = 1
+opcodeEncodingLength (Opnew _)              = 3
 opcodeEncodingLength (Opif_icmplt _)        = 3
 opcodeEncodingLength (Opif_icmple _)        = 3
 opcodeEncodingLength (Opif_icmpgt _)        = 3
@@ -111,7 +127,10 @@ opcodeEncodingLength Opaconst_null          = 1
 opcodeEncodingLength Opreturn               = 1
 opcodeEncodingLength Opireturn              = 1
 opcodeEncodingLength Opareturn              = 1
+opcodeEncodingLength Opdup_x1               = 1
+opcodeEncodingLength Oppop                  = 1
 opcodeEncodingLength (Opinvokespecial _)    = 3
+opcodeEncodingLength (Opinvokevirtual _)    = 3
 opcodeEncodingLength (Opgoto _)             = 3
 opcodeEncodingLength (Opsipush _)           = 3
 opcodeEncodingLength (Opldc_w _)            = 3
@@ -147,11 +166,13 @@ instance Serializable Operation where
     serialize Opisub                    = [0x64]
     serialize Opimul                    = [0x68]
     serialize Opidiv                    = [0x6C]
+    serialize Opirem                    = [0x70]
     serialize Opiand                    = [0x7E]
     serialize Opior                     = [0x80]
     serialize Opixor                    = [0x82]
     serialize Opineg                    = [0x74]
     serialize Opdup                     = [0x59]
+    serialize (Opnew index)             = 0xBB : unpackWord16 index
     serialize (Opif_icmplt branch)      = 0xA1 : unpackWord16 branch
     serialize (Opif_icmple branch)      = 0xA4 : unpackWord16 branch
     serialize (Opif_icmpgt branch)      = 0xA3 : unpackWord16 branch
@@ -162,7 +183,10 @@ instance Serializable Operation where
     serialize Opreturn                  = [0xB1]
     serialize Opireturn                 = [0xAC]
     serialize Opareturn                 = [0xB0]
+    serialize Opdup_x1                  = [0x5A]
+    serialize Oppop                     = [0x57]
     serialize (Opinvokespecial index)   = 0xB7 : unpackWord16 index
+    serialize (Opinvokevirtual index)   = 0xB6 : unpackWord16 index
     serialize (Opgoto index)            = 0xA7 : unpackWord16 index
     serialize (Opsipush index)          = 0x11 : unpackWord16 index
     serialize (Opldc_w index)           = 0x13 : unpackWord16 index

src/ByteCode/Generation/Assembler/ExpressionAndStatement.hs

@@ -1,228 +0,0 @@
-module ByteCode.Generation.Assembler.ExpressionAndStatement where
-
-import Ast
-import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Generation.Generator
-import Data.List
-import Data.Char
-import ByteCode.Generation.Builder.Field
-
-assembleExpression :: Assembler Expression
-assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation op a b))
-    | elem op [Addition, Subtraction, Multiplication, Division, BitwiseAnd, BitwiseOr, BitwiseXor] = let
-            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
-            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
-        in
-            (bConstants, bOps ++ [binaryOperation op], lvars)
-    | elem op [CompareEqual, CompareNotEqual, CompareLessThan, CompareLessOrEqual, CompareGreaterThan, CompareGreaterOrEqual] = let
-            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
-            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
-            cmp_op = comparisonOperation op 9
-            cmp_ops = [cmp_op, Opsipush 0, Opgoto 6, Opsipush 1]
-        in
-            (bConstants, bOps ++ cmp_ops, lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (CharacterLiteral literal)) =
-    (constants, ops ++ [Opsipush (fromIntegral (ord literal))], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (BooleanLiteral literal)) =
-    (constants, ops ++ [Opsipush (if literal then 1 else 0)], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (IntegerLiteral literal))
-    | literal <= 32767 && literal >= -32768 = (constants, ops ++ [Opsipush (fromIntegral literal)], lvars)
-    | otherwise = (constants ++ [IntegerInfo (fromIntegral literal)], ops ++ [Opldc_w (fromIntegral (1 + length constants))], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ NullLiteral) =
-    (constants, ops ++ [Opaconst_null], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression etype (UnaryOperation Not expr)) = let
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        newConstant = fromIntegral (1 + length exprConstants)
-    in case etype of
-        "int" -> (exprConstants ++ [IntegerInfo 0x7FFFFFFF], exprOps ++ [Opldc_w newConstant, Opixor], lvars)
-        "char" -> (exprConstants, exprOps ++ [Opsipush 0xFFFF, Opixor], lvars)
-        "boolean" -> (exprConstants, exprOps ++ [Opsipush 0x01, Opixor], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (UnaryOperation Minus expr)) = let
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-    in
-        (exprConstants, exprOps ++ [Opineg], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (FieldVariable name)) = let
-        fieldIndex = findFieldIndex constants name
-    in case fieldIndex of
-        Just index -> (constants, ops ++ [Opaload 0, Opgetfield (fromIntegral index)], lvars)
-        Nothing -> error ("No such field found in constant pool: " ++ name)
-
-assembleExpression (constants, ops, lvars) (TypedExpression dtype (LocalVariable name)) = let
-        localIndex = findIndex ((==) name) lvars
-        isPrimitive = elem dtype ["char", "boolean", "int"]
-    in case localIndex of
-        Just index -> (constants, ops ++ if isPrimitive then [Opiload (fromIntegral index)] else [Opaload (fromIntegral index)], lvars)
-        Nothing -> error ("No such local variable found in local variable pool: " ++ name)
-
-assembleExpression (constants, ops, lvars) (TypedExpression dtype (StatementExpressionExpression stmtexp)) =
-        assembleStatementExpression (constants, ops, lvars) stmtexp
-
-assembleExpression _ expr = error ("unimplemented: " ++ show expr)
-
-
-
-
--- TODO untested
-assembleStatementExpression :: Assembler StatementExpression
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (Assignment (TypedExpression dtype (LocalVariable name)) expr)) = let
-        localIndex = findIndex ((==) name) lvars
-        (constants_a, ops_a, _) = assembleExpression (constants, ops, lvars) expr
-        isPrimitive = elem dtype ["char", "boolean", "int"]
-    in case localIndex of
-        Just index -> (constants_a, ops_a ++ if isPrimitive then [Opistore (fromIntegral index)] else [Opastore (fromIntegral index)], lvars)
-        Nothing -> error ("No such local variable found in local variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (Assignment (TypedExpression dtype (FieldVariable name)) expr)) = let
-        fieldIndex = findFieldIndex constants name
-        (constants_a, ops_a, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
-    in case fieldIndex of
-        Just index -> (constants_a, ops_a ++ [Opputfield (fromIntegral index)], lvars)
-        Nothing -> error ("No such field variable found in constant pool: " ++ name)
-
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype (LocalVariable name)))) = let
-        localIndex = findIndex ((==) name) lvars
-        expr = (TypedExpression dtype (LocalVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opdup]
-    in case localIndex of
-        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
-        Nothing -> error("No such local variable found in local variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype (LocalVariable name)))) = let
-        localIndex = findIndex ((==) name) lvars
-        expr = (TypedExpression dtype (LocalVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        incrOps = exprOps ++ [Opdup, Opsipush 1, Opiadd]
-    in case localIndex of
-        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
-        Nothing -> error("No such local variable found in local variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype (LocalVariable name)))) = let
-        localIndex = findIndex ((==) name) lvars
-        expr = (TypedExpression dtype (LocalVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opisub]
-    in case localIndex of
-        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
-        Nothing -> error("No such local variable found in local variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype (LocalVariable name)))) = let
-        localIndex = findIndex ((==) name) lvars
-        expr = (TypedExpression dtype (LocalVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        incrOps = exprOps ++ [Opdup, Opsipush 1, Opisub]
-    in case localIndex of
-        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
-        Nothing -> error("No such local variable found in local variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype (FieldVariable name)))) = let
-        fieldIndex = findFieldIndex constants name
-        expr = (TypedExpression dtype (FieldVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
-        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opdup]
-    in case fieldIndex of
-        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
-        Nothing -> error("No such field variable found in field variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype (FieldVariable name)))) = let
-        fieldIndex = findFieldIndex constants name
-        expr = (TypedExpression dtype (FieldVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
-        incrOps = exprOps ++ [Opdup, Opsipush 1, Opiadd]
-    in case fieldIndex of
-        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
-        Nothing -> error("No such field variable found in field variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype (FieldVariable name)))) = let
-        fieldIndex = findFieldIndex constants name
-        expr = (TypedExpression dtype (FieldVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
-        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opisub]
-    in case fieldIndex of
-        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
-        Nothing -> error("No such field variable found in field variable pool: " ++ name)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype (FieldVariable name)))) = let
-        fieldIndex = findFieldIndex constants name
-        expr = (TypedExpression dtype (FieldVariable name))
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
-        incrOps = exprOps ++ [Opdup, Opsipush 1, Opisub]
-    in case fieldIndex of
-        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
-        Nothing -> error("No such field variable found in field variable pool: " ++ name)
-
-
-
-
-
-assembleStatement :: Assembler Statement
-assembleStatement (constants, ops, lvars) (TypedStatement stype (Return expr)) = case expr of
-    Nothing -> (constants, ops ++ [Opreturn], lvars)
-    Just expr -> let
-            (expr_constants, expr_ops, _) = assembleExpression (constants, ops, lvars) expr
-        in
-            (expr_constants, expr_ops ++ [returnOperation stype], lvars)
-assembleStatement (constants, ops, lvars) (TypedStatement _ (Block statements)) =
-    foldl assembleStatement (constants, ops, lvars) statements
-assembleStatement (constants, ops, lvars) (TypedStatement _ (If expr if_stmt else_stmt)) = let
-        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
-        (constants_ifa, ops_ifa, _) = assembleStatement (constants_cmp, [], lvars) if_stmt
-        (constants_elsea, ops_elsea, _) = case else_stmt of
-            Nothing -> (constants_ifa, [], lvars)
-            Just stmt -> assembleStatement (constants_ifa, [], lvars) stmt
-        -- +6 because we insert 2 gotos, one for if, one for else
-        if_length = sum (map opcodeEncodingLength ops_ifa) + 6
-        -- +3 because we need to account for the goto in the if statement.
-        else_length = sum (map opcodeEncodingLength ops_elsea) + 3
-    in
-        (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq if_length] ++ ops_ifa ++ [Opgoto else_length] ++ ops_elsea, lvars)
-assembleStatement (constants, ops, lvars) (TypedStatement _ (While expr stmt)) = let
-        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
-        (constants_stmta, ops_stmta, _) = assembleStatement (constants_cmp, [], lvars) stmt
-        -- +3 because we insert 2 gotos, one for the comparison, one for the goto back to the comparison
-        stmt_length = sum (map opcodeEncodingLength ops_stmta) + 6
-        entire_length = stmt_length + sum (map opcodeEncodingLength ops_cmp)
-    in
-        (constants_stmta, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq stmt_length] ++ ops_stmta ++ [Opgoto (-entire_length)], lvars)
-assembleStatement (constants, ops, lvars) (TypedStatement _ (LocalVariableDeclaration (VariableDeclaration dtype name expr))) = let
-        isPrimitive = elem dtype ["char", "boolean", "int"]
-        (constants_init, ops_init, _) = case expr of
-            Just exp -> assembleExpression (constants, ops, lvars) exp
-            Nothing -> (constants, ops ++ if isPrimitive then [Opsipush 0] else [Opaconst_null], lvars)
-        localIndex = fromIntegral (length lvars)
-        storeLocal = if isPrimitive then [Opistore localIndex] else [Opastore localIndex]
-    in
-        (constants_init, ops_init ++ storeLocal, lvars ++ [name])
-
-assembleStatement (constants, ops, lvars) (TypedStatement _ (StatementExpressionStatement expr)) =
-    assembleStatementExpression (constants, ops, lvars) expr
-
-assembleStatement _ stmt = error ("Not yet implemented: " ++ show stmt)

src/ByteCode/Generation/Assembler/Method.hs

@@ -1,20 +0,0 @@
-module ByteCode.Generation.Assembler.Method where
-
-import Ast
-import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Generation.Generator
-import ByteCode.Generation.Assembler.ExpressionAndStatement
-
-assembleMethod :: Assembler MethodDeclaration
-assembleMethod (constants, ops, lvars) (MethodDeclaration _ name _ (TypedStatement _ (Block statements)))
-    | name == "<init>" = let
-            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
-            init_ops = [Opaload 0, Opinvokespecial 2]
-        in
-            (constants_a, init_ops ++ ops_a ++ [Opreturn], lvars_a)
-    | otherwise = let
-            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
-            init_ops = [Opaload 0]
-        in
-            (constants_a, init_ops ++ ops_a, lvars_a)
-assembleMethod _ (MethodDeclaration _ _ _ stmt) = error ("Block expected for method body, got: " ++ show stmt) 

src/ByteCode/Generation/Builder/Class.hs

@@ -1,44 +0,0 @@
-module ByteCode.Generation.Builder.Class where
-
-import ByteCode.Generation.Builder.Field
-import ByteCode.Generation.Builder.Method
-import ByteCode.Generation.Generator
-import Ast
-import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Constants
-
-injectDefaultConstructor :: [MethodDeclaration] -> [MethodDeclaration]
-injectDefaultConstructor pre
-    | any (\(MethodDeclaration _ name _ _) -> name == "<init>") pre = pre
-    | otherwise = pre ++ [MethodDeclaration "void" "<init>" [] (TypedStatement "void" (Block []))]
-
-
-classBuilder :: ClassFileBuilder Class
-classBuilder (Class name methods fields) _ = let
-        baseConstants = [
-            ClassInfo 4,
-            MethodRefInfo 1 3,
-            NameAndTypeInfo 5 6,
-            Utf8Info "java/lang/Object",
-            Utf8Info "<init>",
-            Utf8Info "()V",
-            Utf8Info "Code"
-            ]
-        nameConstants = [ClassInfo 9, Utf8Info name]
-        nakedClassFile = ClassFile {
-            constantPool = baseConstants ++ nameConstants,
-            accessFlags = accessPublic,
-            thisClass = 8,
-            superClass = 1,
-            fields = [],
-            methods = [],
-            attributes = []
-        }
-
-        methodsWithInjectedConstructor = injectDefaultConstructor methods
-
-        classFileWithFields = foldr fieldBuilder nakedClassFile fields
-        classFileWithMethods = foldr methodBuilder classFileWithFields methodsWithInjectedConstructor
-        classFileWithAssembledMethods = foldr methodAssembler classFileWithMethods methodsWithInjectedConstructor
-    in
-        classFileWithAssembledMethods

src/ByteCode/Generation/Builder/Field.hs

@@ -1,46 +0,0 @@
-module ByteCode.Generation.Builder.Field where
-
-import Ast
-import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Generation.Generator
-import ByteCode.Constants
-import Data.List
-
-findFieldIndex :: [ConstantInfo] -> String -> Maybe Int
-findFieldIndex constants name = let
-        fieldRefNameInfos = [
-                -- we only skip one entry to get the name since the Java constant pool
-                -- is 1-indexed (why)
-                (index, constants!!(fromIntegral index + 1))
-                | (index, FieldRefInfo _ _) <- (zip [1..] constants)
-            ]
-        fieldRefNames = map (\(index, nameInfo) -> case nameInfo of
-            Utf8Info fieldName -> (index, fieldName)
-            something_else -> error ("Expected UTF8Info but got" ++ show something_else))
-                fieldRefNameInfos
-        fieldIndex = find (\(index, fieldName) -> fieldName == name) fieldRefNames
-    in case fieldIndex of
-        Just (index, _) -> Just index
-        Nothing -> Nothing
-
-
-fieldBuilder :: ClassFileBuilder VariableDeclaration
-fieldBuilder (VariableDeclaration datatype name _) input = let
-        baseIndex = 1 + length (constantPool input)
-        constants = [
-                FieldRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
-                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
-                Utf8Info name,
-                Utf8Info (datatypeDescriptor datatype)
-            ]
-        field = MemberInfo {
-            memberAccessFlags = accessPublic,
-            memberNameIndex = (fromIntegral (baseIndex + 2)),
-            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
-            memberAttributes = []
-            }
-    in
-        input {
-            constantPool = (constantPool input) ++ constants,
-            fields = (fields input) ++ [field]
-        }

src/ByteCode/Generation/Builder/Method.hs

@@ -1,80 +0,0 @@
-module ByteCode.Generation.Builder.Method where
-
-import Ast
-import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Generation.Generator
-import ByteCode.Generation.Assembler.Method
-import ByteCode.Constants
-import Data.List
-
-methodDescriptor :: MethodDeclaration -> String
-methodDescriptor (MethodDeclaration returntype _ parameters _) = let
-        parameter_types = [datatype | ParameterDeclaration datatype _ <- parameters]
-    in
-        "("
-        ++ (concat (map methodParameterDescriptor parameter_types))
-        ++ ")"
-        ++ methodParameterDescriptor returntype
-
-methodParameterDescriptor :: String -> String
-methodParameterDescriptor "void" = "V"
-methodParameterDescriptor "int" = "I"
-methodParameterDescriptor "char" = "C"
-methodParameterDescriptor "boolean" = "B"
-methodParameterDescriptor x = "L" ++ x ++ ";"
-
-memberInfoIsMethod :: [ConstantInfo] -> MemberInfo -> Bool
-memberInfoIsMethod constants info = elem '(' (memberInfoDescriptor constants info)
-
-findMethodIndex :: ClassFile -> String -> Maybe Int
-findMethodIndex classFile name = let
-        constants = constantPool classFile
-    in
-        findIndex (\method -> ((memberInfoIsMethod constants method) && (memberInfoName constants method) == name)) (methods classFile)
-
-
-methodBuilder :: ClassFileBuilder MethodDeclaration
-methodBuilder (MethodDeclaration returntype name parameters statement) input = let
-        baseIndex = 1 + length (constantPool input)
-        constants = [
-                Utf8Info name,
-                Utf8Info (methodDescriptor (MethodDeclaration returntype name parameters (Block [])))
-            ]
-
-        method = MemberInfo {
-            memberAccessFlags = accessPublic,
-            memberNameIndex = (fromIntegral baseIndex),
-            memberDescriptorIndex = (fromIntegral (baseIndex + 1)),
-            memberAttributes = []
-            }
-    in 
-        input {
-            constantPool = (constantPool input) ++ constants,
-            methods = (methods input) ++ [method]
-        }
-        
-
-
-methodAssembler :: ClassFileBuilder MethodDeclaration
-methodAssembler (MethodDeclaration returntype name parameters statement) input = let
-        methodConstantIndex = findMethodIndex input name
-    in case methodConstantIndex of
-        Nothing -> error ("Cannot find method entry in method pool for method: " ++ name)
-        Just index -> let
-                declaration = MethodDeclaration returntype name parameters statement
-                paramNames = "this" : [name | ParameterDeclaration _ name <- parameters]
-                (pre, method : post) = splitAt index (methods input)
-                (_, bytecode, _) = assembleMethod (constantPool input, [], paramNames) declaration
-                assembledMethod = method {
-                    memberAttributes = [
-                        CodeAttribute {
-                            attributeMaxStack = 420,
-                            attributeMaxLocals = 420,
-                            attributeCode = bytecode
-                        }
-                    ]
-                }
-            in
-                input {
-                    methods = pre ++ (assembledMethod : post)
-                }

src/ByteCode/Generation/Generator.hs

@@ -1,73 +0,0 @@
-module ByteCode.Generation.Generator(
-    datatypeDescriptor,
-    memberInfoName,
-    memberInfoDescriptor,
-    returnOperation,
-    binaryOperation,
-    comparisonOperation,
-    ClassFileBuilder,
-    Assembler
-) where
-
-import ByteCode.Constants
-import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import Ast
-import Data.Char
-import Data.List
-import Data.Word
-
-type ClassFileBuilder a = a -> ClassFile -> ClassFile
-type Assembler a = ([ConstantInfo], [Operation], [String]) -> a -> ([ConstantInfo], [Operation], [String])
-
-datatypeDescriptor :: String -> String
-datatypeDescriptor "void" = "V"
-datatypeDescriptor "int" = "I"
-datatypeDescriptor "char" = "C"
-datatypeDescriptor "boolean" = "B"
-datatypeDescriptor x = "L" ++ x
-
-memberInfoDescriptor :: [ConstantInfo] -> MemberInfo -> String
-memberInfoDescriptor constants MemberInfo {
-    memberAccessFlags = _,
-    memberNameIndex = _,
-    memberDescriptorIndex = descriptorIndex,
-    memberAttributes = _ } = let
-            descriptor = constants!!((fromIntegral descriptorIndex) - 1)
-        in case descriptor of
-            Utf8Info descriptorText -> descriptorText
-            _ -> ("Invalid Item at Constant pool index " ++ show descriptorIndex)
-
-
-memberInfoName :: [ConstantInfo] -> MemberInfo -> String
-memberInfoName constants MemberInfo {
-    memberAccessFlags = _,
-    memberNameIndex = nameIndex,
-    memberDescriptorIndex = _,
-    memberAttributes = _ } = let
-            name = constants!!((fromIntegral nameIndex) - 1)
-        in case name of
-            Utf8Info nameText -> nameText
-            _ -> ("Invalid Item at Constant pool index " ++ show nameIndex)
-
-
-returnOperation :: DataType -> Operation
-returnOperation dtype
-    | elem dtype ["int", "char", "boolean"] = Opireturn
-    | otherwise                             = Opareturn
-
-binaryOperation :: BinaryOperator -> Operation
-binaryOperation Addition       = Opiadd
-binaryOperation Subtraction    = Opisub
-binaryOperation Multiplication = Opimul
-binaryOperation Division       = Opidiv
-binaryOperation BitwiseAnd     = Opiand
-binaryOperation BitwiseOr      = Opior
-binaryOperation BitwiseXor     = Opixor
-
-comparisonOperation :: BinaryOperator -> Word16 -> Operation
-comparisonOperation CompareEqual          branchLocation = Opif_icmpeq branchLocation
-comparisonOperation CompareNotEqual       branchLocation = Opif_icmpne branchLocation
-comparisonOperation CompareLessThan       branchLocation = Opif_icmplt branchLocation
-comparisonOperation CompareLessOrEqual    branchLocation = Opif_icmple branchLocation
-comparisonOperation CompareGreaterThan    branchLocation = Opif_icmpgt branchLocation
-comparisonOperation CompareGreaterOrEqual branchLocation = Opif_icmpge branchLocation

src/ByteCode/Util.hs

@@ -0,0 +1,245 @@
+module ByteCode.Util where
+
+import Data.Int
+import Ast
+import ByteCode.ClassFile
+import Data.List
+import Data.Maybe (mapMaybe)
+import Data.Word (Word8, Word16, Word32)
+
+-- walks the name resolution chain. returns the innermost Just LocalVariable/FieldVariable or Nothing.
+resolveNameChain :: Expression -> Expression
+resolveNameChain (TypedExpression _ (BinaryOperation NameResolution a b)) = resolveNameChain b
+resolveNameChain (TypedExpression dtype (LocalVariable name)) = (TypedExpression dtype (LocalVariable name))
+resolveNameChain (TypedExpression dtype (FieldVariable name)) = (TypedExpression dtype (FieldVariable name))
+resolveNameChain invalidExpression = error ("expected a NameResolution or Local/Field Variable but got: " ++ show(invalidExpression))
+
+-- walks the name resolution chain. returns the second-to-last item of the namechain.
+resolveNameChainOwner :: Expression -> Expression
+resolveNameChainOwner (TypedExpression _ (BinaryOperation NameResolution a (TypedExpression dtype (FieldVariable name)))) = a
+resolveNameChainOwner (TypedExpression _ (BinaryOperation NameResolution a b)) = resolveNameChain b
+resolveNameChainOwner invalidExpression = error ("expected a NameResolution or Local/Field Variable but got: " ++ show(invalidExpression))
+
+
+methodDescriptor :: MethodDeclaration -> String
+methodDescriptor (MethodDeclaration returntype _ parameters _) = let
+        parameter_types = [datatype | ParameterDeclaration datatype _ <- parameters]
+    in
+        "("
+        ++ (concat (map datatypeDescriptor parameter_types))
+        ++ ")"
+        ++ datatypeDescriptor returntype
+
+methodDescriptorFromParamlist :: [Expression] -> String -> String
+methodDescriptorFromParamlist parameters returntype = let
+        parameter_types = [datatype | TypedExpression datatype _ <- parameters]
+    in
+        "("
+        ++ (concat (map datatypeDescriptor parameter_types))
+        ++ ")"
+        ++ datatypeDescriptor returntype
+
+memberInfoIsMethod :: [ConstantInfo] -> MemberInfo -> Bool
+memberInfoIsMethod constants info = elem '(' (memberInfoDescriptor constants info)
+
+
+datatypeDescriptor :: String -> String
+datatypeDescriptor "void" = "V"
+datatypeDescriptor "int" = "I"
+datatypeDescriptor "char" = "C"
+datatypeDescriptor "boolean" = "B"
+datatypeDescriptor x = "L" ++ x ++ ";"
+
+
+memberInfoDescriptor :: [ConstantInfo] -> MemberInfo -> String
+memberInfoDescriptor constants MemberInfo {
+    memberAccessFlags = _,
+    memberNameIndex = _,
+    memberDescriptorIndex = descriptorIndex,
+    memberAttributes = _ } = let
+            descriptor = constants!!((fromIntegral descriptorIndex) - 1)
+        in case descriptor of
+            Utf8Info descriptorText -> descriptorText
+            _ -> ("Invalid Item at Constant pool index " ++ show descriptorIndex)
+
+
+memberInfoName :: [ConstantInfo] -> MemberInfo -> String
+memberInfoName constants MemberInfo {
+    memberAccessFlags = _,
+    memberNameIndex = nameIndex,
+    memberDescriptorIndex = _,
+    memberAttributes = _ } = let
+            name = constants!!((fromIntegral nameIndex) - 1)
+        in case name of
+            Utf8Info nameText -> nameText
+            _ -> ("Invalid Item at Constant pool index " ++ show nameIndex)
+
+
+returnOperation :: DataType -> Operation
+returnOperation dtype
+    | elem dtype ["int", "char", "boolean"] = Opireturn
+    | otherwise                             = Opareturn
+
+binaryOperation :: BinaryOperator -> Operation
+binaryOperation Addition       = Opiadd
+binaryOperation Subtraction    = Opisub
+binaryOperation Multiplication = Opimul
+binaryOperation Division       = Opidiv
+binaryOperation Modulo         = Opirem
+binaryOperation BitwiseAnd     = Opiand
+binaryOperation BitwiseOr      = Opior
+binaryOperation BitwiseXor     = Opixor
+binaryOperation And            = Opiand
+binaryOperation Or             = Opior
+
+comparisonOperation :: BinaryOperator -> Word16 -> Operation
+comparisonOperation CompareEqual          branchLocation = Opif_icmpeq branchLocation
+comparisonOperation CompareNotEqual       branchLocation = Opif_icmpne branchLocation
+comparisonOperation CompareLessThan       branchLocation = Opif_icmplt branchLocation
+comparisonOperation CompareLessOrEqual    branchLocation = Opif_icmple branchLocation
+comparisonOperation CompareGreaterThan    branchLocation = Opif_icmpgt branchLocation
+comparisonOperation CompareGreaterOrEqual branchLocation = Opif_icmpge branchLocation
+
+findFieldIndex :: [ConstantInfo] -> String -> Maybe Int
+findFieldIndex constants name = let
+        fieldRefNameInfos = [
+                -- we only skip one entry to get the name since the Java constant pool
+                -- is 1-indexed (why)
+                (index, constants!!(fromIntegral index + 1))
+                | (index, FieldRefInfo classIndex _) <- (zip [1..] constants)
+            ]
+        fieldRefNames = map (\(index, nameInfo) -> case nameInfo of
+            Utf8Info fieldName -> (index, fieldName)
+            something_else -> error ("Expected UTF8Info but got" ++ show something_else))
+                fieldRefNameInfos
+        fieldIndex = find (\(index, fieldName) -> fieldName == name) fieldRefNames
+    in case fieldIndex of
+        Just (index, _) -> Just index
+        Nothing -> Nothing
+
+findMethodRefIndex :: [ConstantInfo] -> String -> Maybe Int
+findMethodRefIndex constants name = let
+        methodRefNameInfos = [
+                -- we only skip one entry to get the name since the Java constant pool
+                -- is 1-indexed (why)
+                (index, constants!!(fromIntegral index + 1))
+                | (index, MethodRefInfo _ _) <- (zip [1..] constants)
+            ]
+        methodRefNames = map (\(index, nameInfo) -> case nameInfo of
+            Utf8Info methodName -> (index, methodName)
+            something_else -> error ("Expected UTF8Info but got " ++ show something_else))
+                methodRefNameInfos
+        methodIndex = find (\(index, methodName) -> methodName == name) methodRefNames
+    in case methodIndex of
+        Just (index, _) -> Just index
+        Nothing -> Nothing
+
+
+findMethodIndex :: ClassFile -> String -> Maybe Int
+findMethodIndex classFile name = let
+        constants = constantPool classFile
+    in
+        findIndex (\method -> ((memberInfoIsMethod constants method) && (memberInfoName constants method) == name)) (methods classFile)
+
+findClassIndex :: [ConstantInfo] -> String -> Maybe Int
+findClassIndex constants name = let
+        classNameIndices = [(index, constants!!(fromIntegral nameIndex - 1)) | (index, ClassInfo nameIndex) <- (zip[1..] constants)]
+        classNames = map (\(index, nameInfo) -> case nameInfo of
+            Utf8Info className -> (index, className)
+            something_else -> error("Expected UTF8Info but got " ++ show something_else))
+                classNameIndices
+        desiredClassIndex = find (\(index, className) -> className == name) classNames
+    in case desiredClassIndex of
+        Just (index, _) -> Just index
+        Nothing -> Nothing
+
+getKnownMembers :: [ConstantInfo] -> [(Int, (String, String, String))]
+getKnownMembers constants = let
+        fieldsClassAndNT = [
+                (index, constants!!(fromIntegral classIndex - 1), constants!!(fromIntegral nameTypeIndex - 1))
+                | (index, FieldRefInfo classIndex nameTypeIndex) <- (zip [1..] constants)
+            ] ++ [
+                (index, constants!!(fromIntegral classIndex - 1), constants!!(fromIntegral nameTypeIndex - 1))
+                | (index, MethodRefInfo classIndex nameTypeIndex) <- (zip [1..] constants)
+            ]
+            
+        fieldsClassNameType = map (\(index, nameInfo, nameTypeInfo) -> case (nameInfo, nameTypeInfo) of
+            (ClassInfo nameIndex, NameAndTypeInfo fnameIndex ftypeIndex) -> (index, (constants!!(fromIntegral nameIndex - 1), constants!!(fromIntegral fnameIndex - 1), constants!!(fromIntegral ftypeIndex - 1)))
+            something_else -> error ("Expected Class and NameType info, but got: " ++ show nameInfo ++ " and " ++ show nameTypeInfo))
+                fieldsClassAndNT
+
+        fieldsResolved = map (\(index, (nameInfo, fnameInfo, ftypeInfo)) -> case (nameInfo, fnameInfo, ftypeInfo) of
+            (Utf8Info cname, Utf8Info fname, Utf8Info ftype) -> (index, (cname, fname, ftype))
+            something_else -> error("Expected UTF8Infos but got " ++ show something_else))
+                fieldsClassNameType    
+    in
+        fieldsResolved
+
+-- same as findClassIndex, but inserts a new entry into constant pool if not existing
+getClassIndex :: [ConstantInfo] -> String -> ([ConstantInfo], Int)
+getClassIndex constants name = case findClassIndex constants name of
+    Just index -> (constants, index)
+    Nothing -> (constants ++ [ClassInfo (fromIntegral (length constants)), Utf8Info name], fromIntegral (length constants))
+
+-- get the index for a field within a class, creating it if it does not exist.
+getFieldIndex :: [ConstantInfo] -> (String, String, String) -> ([ConstantInfo], Int)
+getFieldIndex constants (cname, fname, ftype) = case findMemberIndex constants (cname, fname, ftype) of
+    Just index -> (constants, index)
+    Nothing -> let
+            (constantsWithClass, classIndex) = getClassIndex constants cname
+            baseIndex = 1 + length constantsWithClass
+        in
+            (constantsWithClass ++ [
+                FieldRefInfo (fromIntegral classIndex) (fromIntegral (baseIndex + 1)),
+                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
+                Utf8Info fname,
+                Utf8Info (datatypeDescriptor ftype)
+            ], baseIndex)
+
+getMethodIndex :: [ConstantInfo] -> (String, String, String) -> ([ConstantInfo], Int)
+getMethodIndex constants (cname, mname, mtype) = case findMemberIndex constants (cname, mname, mtype) of
+    Just index -> (constants, index)
+    Nothing -> let
+            (constantsWithClass, classIndex) = getClassIndex constants cname
+            baseIndex = 1 + length constantsWithClass
+        in
+            (constantsWithClass ++ [
+                MethodRefInfo (fromIntegral classIndex) (fromIntegral (baseIndex + 1)),
+                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
+                Utf8Info mname,
+                Utf8Info mtype
+            ], baseIndex)
+
+findMemberIndex :: [ConstantInfo] -> (String, String, String) -> Maybe Int
+findMemberIndex constants (cname, fname, ftype) = let
+        allMembers = getKnownMembers constants
+        desiredMember = find (\(index, (c, f, ft)) -> (c, f, ft) == (cname, fname, ftype)) allMembers
+    in
+        fmap (\(index, _) -> index) desiredMember
+
+injectDefaultConstructor :: [MethodDeclaration] -> [MethodDeclaration]
+injectDefaultConstructor pre
+    | any (\(MethodDeclaration _ name _ _) -> name == "<init>") pre = pre
+    | otherwise = pre ++ [MethodDeclaration "void" "<init>" [] (TypedStatement "void" (Block []))]
+
+injectFieldInitializers :: String -> [VariableDeclaration] -> [MethodDeclaration] -> [MethodDeclaration]
+injectFieldInitializers classname vars pre = let 
+        initializers = mapMaybe (\(variable) -> case variable of
+                VariableDeclaration dtype name (Just initializer) -> Just (
+                        TypedStatement dtype (
+                            StatementExpressionStatement (
+                                TypedStatementExpression dtype (
+                                    Assignment
+                                        (TypedExpression dtype (BinaryOperation NameResolution (TypedExpression classname (LocalVariable "this")) (TypedExpression dtype (FieldVariable name))))
+                                        initializer
+                                    )
+                                )
+                            )
+                        )
+                otherwise -> Nothing
+            ) vars
+    in
+        map (\(method) -> case method of
+                MethodDeclaration "void" "<init>" params (TypedStatement "void" (Block statements)) -> MethodDeclaration "void" "<init>" params (TypedStatement "void" (Block (initializers ++ statements)))
+                otherwise -> method
+            ) pre

src/Main.hs

@@ -4,17 +4,30 @@ import Example
 import Typecheck
 import Parser.Lexer (alexScanTokens)
 import Parser.JavaParser
-import ByteCode.Generation.Generator
-import ByteCode.Generation.Builder.Class
+import ByteCode.Builder
 import ByteCode.ClassFile
 import Data.ByteString (pack, writeFile)
+import System.Environment
+import System.FilePath.Posix (takeDirectory)
 
 main = do
-    file <- readFile "Testklasse.java"
+    args <- getArgs
+    let filename = if null args
+                   then error "Missing filename, I need to know what to compile"
+                   else args!!0
+    let outputDirectory = takeDirectory filename
+    print ("Compiling " ++ filename)
+    file <- readFile filename
 
     let untypedAST = parse $ alexScanTokens file
-    let typedAST = head (typeCheckCompilationUnit untypedAST)
-    let abstractClassFile = classBuilder typedAST emptyClassFile
-    let assembledClassFile = pack (serialize abstractClassFile)
+    let typedAST = (typeCheckCompilationUnit untypedAST)
+    let assembledClasses = map (\(typedClass) -> classBuilder typedClass emptyClassFile) typedAST
+
+    mapM_ (\(classFile) -> let
+            fileContent = pack (serialize classFile)
+            fileName = outputDirectory ++ "/" ++ (className classFile) ++ ".class"
+        in Data.ByteString.writeFile fileName fileContent
+        ) assembledClasses
+
+
     
-    Data.ByteString.writeFile "Testklasse.class" assembledClassFile