From e8cc6ade11f5129e250e0a50bba4aac1ab413e4a Mon Sep 17 00:00:00 2001
From: Victorious3 <vic@nightfall.moe>
Date: Wed, 27 Apr 2022 13:05:01 +0200
Subject: [PATCH] Start working on the code generator

---
 .../target/bytecode/Codegen.java              | 57 +++++++++++++++++++
 .../target/tree/TargetConstructor.java        |  5 ++
 .../target/tree/TargetField.java              |  6 +-
 .../target/tree/TargetMethod.java             |  4 ++
 .../target/tree/type/TargetRefType.java       |  4 ++
 .../target/tree/type/TargetType.java          |  2 +
 6 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100755 src/main/java/de/dhbwstuttgart/target/bytecode/Codegen.java

diff --git a/src/main/java/de/dhbwstuttgart/target/bytecode/Codegen.java b/src/main/java/de/dhbwstuttgart/target/bytecode/Codegen.java
new file mode 100755
index 00000000..90a04fb0
--- /dev/null
+++ b/src/main/java/de/dhbwstuttgart/target/bytecode/Codegen.java
@@ -0,0 +1,57 @@
+package de.dhbwstuttgart.target.bytecode;
+
+import de.dhbwstuttgart.target.tree.TargetClass;
+import de.dhbwstuttgart.target.tree.TargetConstructor;
+import de.dhbwstuttgart.target.tree.TargetField;
+import de.dhbwstuttgart.target.tree.TargetMethod;
+import de.dhbwstuttgart.target.tree.expression.TargetBlock;
+import de.dhbwstuttgart.target.tree.type.TargetType;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.MethodVisitor;
+
+import static org.objectweb.asm.Opcodes.*;
+
+public class Codegen {
+    private TargetClass clazz;
+    private ClassWriter cw;
+
+    public Codegen(TargetClass clazz) {
+        this.clazz = clazz;
+        this.cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
+    }
+
+    private void generateBlock(MethodVisitor mv, TargetBlock block) {
+
+    }
+
+    private void generateField(TargetField field) {
+        cw.visitField(field.access(), field.name(), field.getDescriptor(), null, null);
+    }
+
+    private void generateConstructor(TargetConstructor constructor) {
+        MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", constructor.getDescriptor(), null, null);
+        mv.visitEnd();
+    }
+
+    private void generateMethod(TargetMethod method) {
+        // TODO Access modifier
+        MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, method.name(), method.getDescriptor(), null, null);
+        generateBlock(mv, method.block());
+        mv.visitMaxs(0, 0);
+        mv.visitEnd();
+    }
+
+    public byte[] generate() {
+        // TODO Access modifier and signature
+        cw.visit(V12, ACC_PUBLIC, clazz.qualifiedName(),
+                null, clazz.superType().toSignature(),
+                clazz.implementingInterfaces().stream().map(TargetType::toSignature).toArray(String[]::new)
+        );
+        clazz.fields().forEach(this::generateField);
+        clazz.constructors().forEach(this::generateConstructor);
+        clazz.methods().forEach(this::generateMethod);
+
+        cw.visitEnd();
+        return cw.toByteArray();
+    }
+}
diff --git a/src/main/java/de/dhbwstuttgart/target/tree/TargetConstructor.java b/src/main/java/de/dhbwstuttgart/target/tree/TargetConstructor.java
index b93219ff..94aab071 100644
--- a/src/main/java/de/dhbwstuttgart/target/tree/TargetConstructor.java
+++ b/src/main/java/de/dhbwstuttgart/target/tree/TargetConstructor.java
@@ -3,5 +3,10 @@ package de.dhbwstuttgart.target.tree;
 import java.util.List;
 
 public record TargetConstructor(List<MethodParameter> parameterTypes) {
+
+    public String getDescriptor() {
+        // TODO
+        return null;
+    }
 }
 
diff --git a/src/main/java/de/dhbwstuttgart/target/tree/TargetField.java b/src/main/java/de/dhbwstuttgart/target/tree/TargetField.java
index cbba1dec..c466b159 100644
--- a/src/main/java/de/dhbwstuttgart/target/tree/TargetField.java
+++ b/src/main/java/de/dhbwstuttgart/target/tree/TargetField.java
@@ -2,6 +2,10 @@ package de.dhbwstuttgart.target.tree;
 
 import de.dhbwstuttgart.target.tree.type.TargetType;
 
-public record TargetField(TargetType type, String name) {
+public record TargetField(int access, TargetType type, String name) {
+    public String getDescriptor() {
+        // TODO
+        return null;
+    }
 }
 
diff --git a/src/main/java/de/dhbwstuttgart/target/tree/TargetMethod.java b/src/main/java/de/dhbwstuttgart/target/tree/TargetMethod.java
index 6538b7a5..9c50f6e7 100644
--- a/src/main/java/de/dhbwstuttgart/target/tree/TargetMethod.java
+++ b/src/main/java/de/dhbwstuttgart/target/tree/TargetMethod.java
@@ -5,5 +5,9 @@ import de.dhbwstuttgart.target.tree.expression.TargetBlock;
 import java.util.List;
 
 public record TargetMethod(String name, List<MethodParameter> parameterTypes, TargetBlock block) {
+    public String getDescriptor() {
+        // TODO
+        return null;
+    }
 }
 
diff --git a/src/main/java/de/dhbwstuttgart/target/tree/type/TargetRefType.java b/src/main/java/de/dhbwstuttgart/target/tree/type/TargetRefType.java
index 1c27cd62..33c38f5d 100644
--- a/src/main/java/de/dhbwstuttgart/target/tree/type/TargetRefType.java
+++ b/src/main/java/de/dhbwstuttgart/target/tree/type/TargetRefType.java
@@ -5,4 +5,8 @@ import de.dhbwstuttgart.target.tree.type.TargetType;
 import java.util.List;
 
 public record TargetRefType(String name, List<TargetType> params) implements TargetType {
+    @Override
+    public String toSignature() {
+        return this.name;
+    }
 }
diff --git a/src/main/java/de/dhbwstuttgart/target/tree/type/TargetType.java b/src/main/java/de/dhbwstuttgart/target/tree/type/TargetType.java
index eed6dcab..f4d8f7d0 100644
--- a/src/main/java/de/dhbwstuttgart/target/tree/type/TargetType.java
+++ b/src/main/java/de/dhbwstuttgart/target/tree/type/TargetType.java
@@ -2,4 +2,6 @@ package de.dhbwstuttgart.target.tree.type;
 
 public sealed interface TargetType
         permits TargetExtendsWildcard, TargetFunNType, TargetGenericType, TargetRefType, TargetSuperWildcard {
+
+    public String toSignature();
 }