From ff9890437d92c83cb8e1491fb8abd167de2553f0 Mon Sep 17 00:00:00 2001
From: "Tristan B. Kildaire" <deavmi@disroot.org>
Date: Tue, 2 Nov 2021 15:13:44 +0200
Subject: [PATCH] Working code emitter and doing some code gen with it too

---
 source/tlang/compiler/codegen/emit/core.d |  18 +++-
 source/tlang/compiler/codegen/emit/dgen.d | 105 +++++++++++++++++++++-
 source/tlang/compiler/compiler.d          |  10 ++-
 3 files changed, 128 insertions(+), 5 deletions(-)

diff --git a/source/tlang/compiler/codegen/emit/core.d b/source/tlang/compiler/codegen/emit/core.d
index 11f37cd..2092da0 100644
--- a/source/tlang/compiler/codegen/emit/core.d
+++ b/source/tlang/compiler/codegen/emit/core.d
@@ -2,6 +2,10 @@ module compiler.codegen.emit.core;
 
 import compiler.symbols.data;
 import compiler.typecheck.core;
+import std.container.slist : SList;
+import compiler.codegen.instruction;
+import std.stdio;
+import std.file;
 
 /**
 * TODO: Perhaps have an interface that can emit(Context/Parent, Statement)
@@ -11,11 +15,21 @@ import compiler.typecheck.core;
 
 public abstract class CodeEmitter
 {
-    private TypeChecker typeChecker;
+    protected TypeChecker typeChecker;
     
-    this(TypeChecker typeChecker)
+    /**
+    * The code queue
+    */
+    protected SList!(Instruction) codeQueue;
+    alias instructions = codeQueue;
+
+    protected File file;
+
+    this(TypeChecker typeChecker, File file)
     {
         this.typeChecker = typeChecker;
+        codeQueue = typeChecker.getCodeQueue();
+        this.file = file;
     }
 
     public abstract void emit();
diff --git a/source/tlang/compiler/codegen/emit/dgen.d b/source/tlang/compiler/codegen/emit/dgen.d
index 0dd34a4..bc1e3cc 100644
--- a/source/tlang/compiler/codegen/emit/dgen.d
+++ b/source/tlang/compiler/codegen/emit/dgen.d
@@ -2,16 +2,117 @@ module compiler.codegen.emit.dgen;
 
 import compiler.codegen.emit.core : CodeEmitter;
 import compiler.typecheck.core;
+import std.container.slist : SList;
+import compiler.codegen.instruction;
+import std.stdio;
+import std.file;
+
 
 public final class DCodeEmitter : CodeEmitter
 {
-    this(TypeChecker typeChecker)
+    this(TypeChecker typeChecker, File file)
     {
-        super(typeChecker);
+        super(typeChecker, file);
+    }
+
+    /**
+    * TODO: We will need state as to where we are etc.
+    */
+
+    private ulong pushCount;
+
+    /**
+    * RSP value before we started (needed for proper D exit/restore/main()-unwind)
+    *
+    * R15 (Richard 15) <- never use this register besides here and `restoreDInfo()`
+    */
+    private void saveDInfo()
+    {
+        file.writeln(`
+        asm
+        {
+            mov R15, RSP;
+        }
+        `);
+    }
+    private void restoreDInfo()
+    {
+        file.writeln(`
+        asm
+        {
+            mov RSP, R15;
+        }
+        `);
     }
 
     public override void emit()
     {
+        /* Emit initial struccture */
+        emitIninitailModule();
+
+        /* Save D info */
+        saveDInfo();
+
         /* TODO: Implement me */
+        foreach(Instruction instruction; instructions)
+        {
+            /**
+            * compiler.codegen.instruction.VariableDeclaration
+            */
+            if(cast(VariableDeclaration)instruction)
+            {
+                VariableDeclaration varDecInstr = cast(compiler.codegen.instruction.VariableDeclaration)instruction;
+
+                file.writeln(`asm
+                {
+                    sub RSP, 4;
+                    mov dword ptr [RSP], 69;
+                }
+                `);
+
+                
+
+                /* TODO: We need to build map of stakc positions, maybe not */
+            }
+            /**
+            * compiler.codegen.instruction.VariableAssignmentInstr
+            */
+            else if(cast(VariableAssignmentInstr)instruction)
+            {
+                VariableAssignmentInstr varAssInstr = cast(compiler.codegen.instruction.VariableAssignmentInstr)instruction;
+
+                /* Recursively descend soon */
+                
+                // writeln("int "~varDecInstr.varName~";");
+            }
+            
+        }
+
+        /* Restore D info */
+        restoreDInfo();
+
+        /* Close the module */
+        closeModule();
+    }
+
+    private void emitIninitailModule()
+    {
+        /* TODO: Maybe emit as d name */
+        file.writeln("module "~typeChecker.getModule().getName()~";");
+        file.writeln("void main()");
+        file.writeln("{");
+    }
+
+    private void closeModule()
+    {
+        /* Restore for D exit */
+
+        file.writeln(`
+        int h = -1;
+        h = *((&h)-4);
+        import std.stdio;
+        writeln(h);
+        `);
+        file.writeln("}");
     }
 }
\ No newline at end of file
diff --git a/source/tlang/compiler/compiler.d b/source/tlang/compiler/compiler.d
index 03e28d3..ad88889 100644
--- a/source/tlang/compiler/compiler.d
+++ b/source/tlang/compiler/compiler.d
@@ -70,8 +70,16 @@ void beginCompilation(string[] sourceFiles)
             TypeChecker typeChecker = new TypeChecker(modulle);
             typeChecker.beginCheck();
 
-            CodeEmitter emitter = new DCodeEmitter(typeChecker);
+
+            File outFile;
+            outFile.open("test.d", "w");
+            CodeEmitter emitter = new DCodeEmitter(typeChecker, outFile);
+
+            
+            
             emitter.emit();
+            outFile.close();
+
         }
         // catch(CollidingNameException e)
         // {