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namespace Q1.Compiler.visitors;
using System.Text;
using Antlr4.Runtime.Tree;
using Q1.Emulator;
public partial class CCompilerVisitor : CGrammarBaseVisitor<object?>
{
private int _branchCount = 1;
private List<string> _instructions = new();
private Stack<Dictionary<string, VariableReference>> _variableStack = new();
private List<FunctionReference> _methods = new();
private static int _memLowest = Q1Layout.FreeMemoryStart;
private static int _memPointer = CCompilerVisitor._memLowest;
private const int ColumnWidth = 30;
public readonly CommentCompilationMode CommentMode;
public CCompilerVisitor(CommentCompilationMode commentMode, Encoding encoding)
{
this.CommentMode = commentMode;
this.Encoding = encoding;
}
private string GenerateBranchLabel(string type)
{
return $"_{type}_{this._branchCount++}";
}
private void Instruction(string instruction, string? generatedComment = null)
{
this._instructions.Add($" {instruction}");
if (generatedComment != null)
this.CommentLastInstruction(generatedComment);
}
private void Blank()
{
this._instructions.Add("");
}
private void Branch(string name, string? generatedComment = null)
{
this._instructions.Add($"{name}:");
if (generatedComment != null)
this.CommentLastInstruction(generatedComment);
}
private void UserComment(string comment)
{
if (this.CommentMode.HasFlag(CommentCompilationMode.UserDefined))
this._instructions.Add($" ; {comment}");
}
private void GeneratedComment(string comment)
{
if (this.CommentMode.HasFlag(CommentCompilationMode.Generated))
this._instructions.Add($"{"".PadRight(CCompilerVisitor.ColumnWidth)}; {comment}");
}
private void CommentLastInstruction(string comment)
{
if (!this.CommentMode.HasFlag(CommentCompilationMode.Generated))
return;
if (this._instructions.Count == 0)
throw new Exception("Cannot add comment to last instruction, there are none");
string lastInstruction = this._instructions[^1];
lastInstruction = $"{lastInstruction.PadRight(CCompilerVisitor.ColumnWidth)}; {comment}";
this._instructions[^1] = lastInstruction;
}
public IEnumerable<string> Compile(CGrammarParser.ProgramContext program)
{
this.Instruction("jmp _main");
this.Visit(program);
foreach ((CGrammarParser.FunctionDefinitionContext context,
FunctionReference function, FunctionOverload overload,
List<string> paramNames, List<CType> paramTypes) in this._functionBodies)
this.VisitFunctionBody(context, function, overload, paramNames, paramTypes);
return this._instructions;
}
private Dictionary<string, VariableReference> EnterScope()
{
Dictionary<string, VariableReference> scope = new();
this._variableStack.Push(scope);
return scope;
}
private void ExitScope()
{
foreach ((string key, VariableReference value) in this._variableStack.Peek())
{
// CCompilerVisitor._memPointer -= value.Type.Size;
// if (CCompilerVisitor._memPointer < CCompilerVisitor._memLowest)
// throw new CompilerException("Memory pointer is lower than mem lowest!");
}
// Delete scope
this._variableStack.Pop();
}
public void DynamicMove(CType type, string source, string dest, string? comment = null)
{
if (type.Size == 1)
this.Instruction($"movb {source}, {dest}", comment);
else if (type.Size == 2)
this.Instruction($"mov {source}, {dest}", comment);
else
throw new CompilerException($"Cannot move {type.Size} bytes {source} to {dest}");
}
private CType VisitCType(CGrammarParser.TypeContext typeContext)
{
return GetCType(typeContext.GetText().Trim());
}
private CType GetCType(string type)
{
return type switch
{
"int" => CType.Int,
"char" => CType.Char,
_ when type.EndsWith("*") => new CTypePtr(this.GetCType(type[..^1])),
_ => throw new CompilerException($"Unknown CTYPE '{type}'")
};
}
public override object? VisitErrorNode(IErrorNode node)
{
if (node.Symbol.Type == CGrammarParser.COMMENT)
{
// strip // and \n and whitespace
string comment = node
.Symbol.Text
.TrimStart("//")
.TrimEnd('\n')
.Trim();
this.UserComment(comment);
}
if (node.Symbol.Type == CGrammarParser.DIRECTIVE)
{
// strip // and \n and whitespace
string directive = node
.Symbol.Text
.TrimStart("#")
.TrimEnd('\n')
.Trim();
this.Instruction("." + directive);
}
return base.VisitErrorNode(node);
}
public override object? Visit(IParseTree tree)
{
if (tree is Context childCtx && tree.Parent is Context ctx)
ctx.SyncProps(childCtx);
return base.Visit(tree);
}
/// <summary>
/// Basically identical to base version, except calls Visit on each child, making Visit not redundant.
/// </summary>
public override object? VisitChildren(IRuleNode node)
{
object? result = this.DefaultResult;
int childCount = node.ChildCount;
for (int i = 0; i < childCount && this.ShouldVisitNextChild(node, result); ++i)
{
object? nextResult = this.Visit(node.GetChild(i));
result = this.AggregateResult(result, nextResult);
}
return result;
}
}
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