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fixed method/constructor overloading in bytecode generator

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This commit is contained in:
Matthias Raba 2024-06-28 09:20:03 +02:00
parent dee1fcb2df
commit 0e1f31080e
6 changed files with 48 additions and 42 deletions
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9
Test/JavaSources/Main.java
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@ -16,7 +16,8 @@ public class Main {
TestRecursion recursion = new TestRecursion(10);
TestMalicious malicious = new TestMalicious();
TestLoop loop = new TestLoop();
TestMethodOverload overload = new TestMethodOverload();
// constructing a basic class works
assert empty != null;
// initializers (and default initializers to 0/null) work
@ -34,6 +35,12 @@ public class Main {
// self-referencing methods work.
assert recursion.fibonacci(15) == 610;
assert loop.factorial(5) == 120;
// methods with the same name but different parameters work
assert overload.MethodOverload() == 42;
assert overload.MethodOverload(15) == 42 + 15;
// constructor overloading works, too.
assert (new TestConstructorOverload()).a == 42;
assert (new TestConstructorOverload(12)).a == 12;
// intentionally dodgy expressions work
assert malicious.assignNegativeIncrement(42) == -42;
assert malicious.tripleAddition(1, 2, 3) == 6;

9
Test/JavaSources/TestConstructorOverload.java
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@ -1,13 +1,12 @@
public class TestConstructorOverload {
public int a = 42;
TestConstructorOverload() {
// nothing here, so a will assume the default value 42.
}
TestConstructorOverload(int a) {
}
public void test() {
int a = 3;
TestConstructorOverload test = new TestConstructorOverload(a);
this.a = a;
}
}

12
Test/JavaSources/TestMethodOverload.java
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@ -1,14 +1,10 @@
public class TestMethodOverload {
public void MethodOverload() {
public int MethodOverload() {
return 42;
}
public void MethodOverload(int a) {
public int MethodOverload(int a) {
return 42 + a;
}
public void test() {
int a = 3;
MethodOverload(a);
}
}

1
project.cabal
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@ -18,7 +18,6 @@ executable compiler
other-modules: Parser.Lexer,
Parser.JavaParser,
Ast,
Example,
Typecheck,
ByteCode.Util,
ByteCode.ByteUtil,

28
src/ByteCode/Builder.hs
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@ -56,10 +56,13 @@ methodBuilder (MethodDeclaration returntype name parameters statement) input = l
methods = methods input ++ [method]
}
constructorBuilder :: ClassFileBuilder ConstructorDeclaration
constructorBuilder (ConstructorDeclaration name parameters statement) = methodBuilder (MethodDeclaration "void" "<init>" parameters statement)
methodAssembler :: ClassFileBuilder MethodDeclaration
methodAssembler (MethodDeclaration returntype name parameters statement) input = let
methodConstantIndex = findMethodIndex input name
methodConstantIndex = findMethodIndex input (MethodDeclaration returntype name parameters statement)
in case methodConstantIndex of
Nothing -> error ("Cannot find method entry in method pool for method: " ++ name)
Just index -> let
@ -84,9 +87,12 @@ methodAssembler (MethodDeclaration returntype name parameters statement) input =
methods = pre ++ (assembledMethod : post)
}
constructorAssembler :: ClassFileBuilder ConstructorDeclaration
constructorAssembler (ConstructorDeclaration name parameters statement) = methodAssembler (MethodDeclaration "void" "<init>" parameters statement)
classBuilder :: ClassFileBuilder Class
classBuilder (Class name methods fields) _ = let
classBuilder (Class name constructors methods fields) _ = let
baseConstants = [
ClassInfo 4,
MethodRefInfo 1 3,
@ -108,15 +114,15 @@ classBuilder (Class name methods fields) _ = let
attributes = []
}
-- if a class has no constructor, inject an empty one.
methodsWithInjectedConstructor = injectDefaultConstructor methods
-- for every constructor, prepend all initialization assignments for fields.
methodsWithInjectedInitializers = injectFieldInitializers name fields methodsWithInjectedConstructor
constructorsWithInitializers = injectFieldInitializers name fields constructors
-- add fields, then method bodies to the classfile. After all referable names are known,
-- assemble the methods into bytecode.
classFileWithFields = foldr fieldBuilder nakedClassFile fields
classFileWithMethods = foldr methodBuilder classFileWithFields methodsWithInjectedInitializers
classFileWithAssembledMethods = foldr methodAssembler classFileWithMethods methodsWithInjectedInitializers
-- add fields, then method bodies, then constructor bodies to the classfile. After all referable names are known,
-- assemble the methods and constructors into bytecode.
fieldsAdded = foldr fieldBuilder nakedClassFile fields
methodsAdded = foldr methodBuilder fieldsAdded methods
constructorsAdded = foldr constructorBuilder methodsAdded constructorsWithInitializers
methodsAssembled = foldr methodAssembler constructorsAdded methods
constructorsAssembled = foldr constructorAssembler methodsAssembled constructorsWithInitializers
in
classFileWithAssembledMethods
constructorsAssembled

31
src/ByteCode/Util.hs
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@ -1,3 +1,5 @@
{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
{-# HLINT ignore "Use lambda-case" #-}
module ByteCode.Util where
import Data.Int
@ -131,11 +133,12 @@ comparisonOffset anything_else = Nothing
isComparisonOperation :: Operation -> Bool
isComparisonOperation op = isJust (comparisonOffset op)
findMethodIndex :: ClassFile -> String -> Maybe Int
findMethodIndex classFile name = let
findMethodIndex :: ClassFile -> MethodDeclaration -> Maybe Int
findMethodIndex classFile (MethodDeclaration rtype name params stmt) = let
constants = constantPool classFile
descriptor = methodDescriptor (MethodDeclaration rtype name params stmt)
in
findIndex (\method -> memberInfoIsMethod constants method && memberInfoName constants method == name) (methods classFile)
findIndex (\method -> memberInfoIsMethod constants method && memberInfoName constants method == name && memberInfoDescriptor constants method == descriptor) (methods classFile)
findClassIndex :: [ConstantInfo] -> String -> Maybe Int
findClassIndex constants name = let
@ -211,16 +214,11 @@ 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
fmap fst 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
injectFieldInitializers :: String -> [VariableDeclaration] -> [ConstructorDeclaration] -> [ConstructorDeclaration]
injectFieldInitializers classname vars constructors = let
initializers = mapMaybe (\variable -> case variable of
VariableDeclaration dtype name (Just initializer) -> Just (
TypedStatement dtype (
StatementExpressionStatement (
@ -235,10 +233,11 @@ injectFieldInitializers classname vars pre = let
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)))
_ -> method
) pre
map (\con -> let
ConstructorDeclaration classname params (TypedStatement "void" (Block statements)) = con
in
ConstructorDeclaration classname params (TypedStatement "void" (Block (initializers ++ statements)))
) constructors
-- effect of one instruction/operation on the stack
operationStackCost :: [ConstantInfo] -> Operation -> Int