begin cmd

asm/amd64/amd64.go

@@ -0,0 +1,115 @@
+package amd64
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Program struct {
+	Functions []Function
+}
+
+func (p *Program) Emit() string {
+	var builder strings.Builder
+
+	for _, function := range p.Functions {
+		builder.WriteString(function.Emit())
+		builder.WriteString("\n")
+	}
+
+	return builder.String()
+}
+
+type Function struct {
+	Name         string
+	Instructions []Instruction
+}
+
+// This calls the main function and uses it's return value to exit
+const executableAsmHeader = "format ELF64 executable\n" +
+	"segment readable executable\n" +
+	"entry _start\n" +
+	"_start:\n" +
+	"  call main\n" +
+	"  mov rdi, rax\n" +
+	"  mov rax, 60\n" +
+	"  syscall\n"
+
+func (f *Function) Emit() string {
+	var builder strings.Builder
+
+	builder.WriteString(executableAsmHeader)
+	builder.WriteString(fmt.Sprintf("%s:\n", f.Name))
+
+	for _, inst := range f.Instructions {
+		builder.WriteString(fmt.Sprintf("  %s\n", inst.InstructionString()))
+	}
+
+	return builder.String()
+}
+
+type Opcode string
+
+const (
+	Mov Opcode = "mov"
+	Ret Opcode = "ret"
+)
+
+type Instruction struct {
+	Opcode Opcode
+	Lhs    Operand
+	Rhs    Operand
+}
+
+func (i *Instruction) InstructionString() string {
+	if i.Lhs == nil {
+		return fmt.Sprintf("%s", i.Opcode)
+	}
+
+	return fmt.Sprintf("%s %s, %s", i.Opcode, i.Lhs.OperandString(Eight), i.Rhs.OperandString(Eight))
+}
+
+type OperandSize int
+
+type Operand interface {
+	OperandString(OperandSize) string
+}
+
+type Register int
+
+const (
+	AX Register = iota
+	R10
+
+	One OperandSize = iota
+	Four
+	Eight
+)
+
+func (r Register) OperandString(size OperandSize) string {
+	switch r {
+	case AX:
+		switch size {
+		case One:
+			return "al"
+		case Four:
+			return "eax"
+		}
+		return "rax"
+	case R10:
+		switch size {
+		case One:
+			return "r10b"
+		case Four:
+			return "r10d"
+		}
+		return "r10"
+	}
+	return "INVALID_REGISTER"
+}
+
+type Imm int64
+
+func (i Imm) OperandString(size OperandSize) string {
+	return fmt.Sprintf("%d", i)
+}

asm/amd64/amd64_test.go

@@ -0,0 +1,136 @@
+package amd64
+
+import (
+	"strings"
+	"testing"
+
+	"robaertschi.xyz/robaertschi/tt/ttir"
+)
+
+func TestOperands(t *testing.T) {
+	var op Operand
+
+	op = AX
+	if str := op.OperandString(One); str != "al" {
+		t.Errorf("The register AX should be \"al\" but got %q", str)
+	}
+
+	op = Imm(3)
+	if str := op.OperandString(One); str != "3" {
+		t.Errorf("The immediate value 3 should be \"3\" but got %q", str)
+	}
+}
+
+func TestCodegen(t *testing.T) {
+	program := ttir.Program{
+		Functions: []ttir.Function{
+			{
+				Name: "main",
+				Instructions: []ttir.Instruction{
+					&ttir.Ret{Op: &ttir.Constant{Value: 0}},
+				},
+			},
+		},
+	}
+
+	expectedProgram := Program{
+		Functions: []Function{
+			{
+				Name: "main",
+				Instructions: []Instruction{
+					{
+						Opcode: Mov,
+						Lhs:    AX,
+						Rhs:    Imm(0),
+					},
+					{
+						Opcode: Ret,
+					},
+				},
+			},
+		},
+	}
+
+	actualProgram := CgProgram(program)
+	expectProgram(t, expectedProgram, actualProgram)
+
+	actual := actualProgram.Emit()
+
+	expected := executableAsmHeader + "main:\n  mov rax, 0\n  ret\n"
+	if strings.Trim(actual, " \n\t") != strings.Trim(expected, " \n\t") {
+		t.Errorf("Expected program to be:\n>>%s<<\nbut got:\n>>%s<<\n", expected, actual)
+	}
+}
+
+func expectProgram(t *testing.T, expected Program, actual Program) {
+	t.Helper()
+	if len(expected.Functions) != len(actual.Functions) {
+		t.Errorf("Expected %d functions but got %d", len(expected.Functions), len(actual.Functions))
+		return
+	}
+
+	for i := range expected.Functions {
+		expectFunction(t, expected.Functions[i], actual.Functions[i])
+	}
+}
+
+func expectFunction(t *testing.T, expected Function, actual Function) {
+	t.Helper()
+	if expected.Name != actual.Name {
+		t.Errorf("Expected function name %q but got %q", expected.Name, actual.Name)
+	}
+
+	if len(expected.Instructions) != len(actual.Instructions) {
+		t.Errorf("Expected %d instructions but got %d, expected: %v, actual: %v", len(expected.Instructions), len(actual.Instructions), expected.Instructions, actual.Instructions)
+		return
+	}
+
+	for i := range expected.Instructions {
+		expectInstruction(t, expected.Instructions[i], actual.Instructions[i])
+	}
+}
+
+func expectInstruction(t *testing.T, expected Instruction, actual Instruction) {
+	t.Helper()
+	if expected.Opcode != actual.Opcode {
+		t.Errorf("Expected opcode %q but got %q", expected.Opcode, actual.Opcode)
+	}
+
+	switch expected.Opcode {
+	case Mov:
+		expectOperand(t, expected.Lhs, actual.Lhs)
+		expectOperand(t, expected.Rhs, actual.Rhs)
+	case Ret:
+		// nothing to do
+	}
+
+}
+
+func expectOperand(t *testing.T, expected Operand, actual Operand) {
+	t.Helper()
+
+	switch expected := expected.(type) {
+	case Register:
+		actual, ok := actual.(Register)
+		if !ok {
+			t.Errorf("Expected Register but got %T", actual)
+			return
+		}
+
+		if expected != actual {
+			t.Errorf("Expected Register %q but got %q", expected, actual)
+		}
+	case Imm:
+		actual, ok := actual.(Imm)
+		if !ok {
+			t.Errorf("Expected Immediate but got %T", actual)
+			return
+		}
+
+		if expected != actual {
+			t.Errorf("Expected Immediate %q but got %q", expected, actual)
+		}
+	default:
+		t.Errorf("Unknown operand type %T", expected)
+	}
+}

asm/amd64/codegen.go

@@ -0,0 +1,59 @@
+package amd64
+
+import (
+	"fmt"
+
+	"robaertschi.xyz/robaertschi/tt/ttir"
+)
+
+func toAsmOperand(op ttir.Operand) Operand {
+	switch op := op.(type) {
+	case *ttir.Constant:
+		return Imm(op.Value)
+	default:
+		panic(fmt.Sprintf("unkown operand %T", op))
+	}
+}
+
+func CgProgram(prog ttir.Program) Program {
+	funcs := make([]Function, 0)
+
+	for _, f := range prog.Functions {
+		funcs = append(funcs, cgFunction(f))
+	}
+
+	return Program{
+		Functions: funcs,
+	}
+}
+
+func cgFunction(f ttir.Function) Function {
+	newInstructions := []Instruction{}
+
+	for _, inst := range f.Instructions {
+		newInstructions = append(newInstructions, cgInstruction(inst)...)
+	}
+
+	return Function{
+		Name:         f.Name,
+		Instructions: newInstructions,
+	}
+}
+
+func cgInstruction(i ttir.Instruction) []Instruction {
+	switch i := i.(type) {
+	case *ttir.Ret:
+		return []Instruction{
+			{
+				Opcode: Mov,
+				Lhs:    AX,
+				Rhs:    toAsmOperand(i.Op),
+			},
+			{
+				Opcode: Ret,
+			},
+		}
+	}
+
+	return []Instruction{}
+}

cmd/cmd.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+func main() {
+
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s [flags] input\nPossible flags:\n", os.Args[0])
+		flag.PrintDefaults()
+	}
+
+	var output string
+	flag.StringVar(&output, "o", "", "Output a executable named `file`")
+	flag.StringVar(&output, "output", "", "Output a executable named `file`")
+	flag.Parse()
+
+	input := flag.Arg(0)
+	if input == "" {
+		flag.Usage()
+		os.Exit(1)
+	}
+}

test.asm

@@ -0,0 +1,13 @@
+format ELF64 executable
+
+segment readable executable
+main:
+    mov rax, 0
+    ret
+
+entry _start
+_start:
+    call main
+    mov rdi, rax
+    mov rax, 60
+    syscall

ttir/emit.go

@@ -18,7 +18,7 @@ func EmitProgram(program *tast.Program) *Program {
 
 func emitFunction(function *tast.FunctionDeclaration) *Function {
 	value, instructions := emitExpression(function.Body)
-	instructions = append(instructions, &Ret{op: value})
+	instructions = append(instructions, &Ret{Op: value})
 	return &Function{
 		Name:         function.Name,
 		Instructions: instructions,

ttir/ttir.go

@@ -30,11 +30,11 @@ type Instruction interface {
 }
 
 type Ret struct {
-	op Operand
+	Op Operand
 }
 
 func (r *Ret) String() string {
-	return fmt.Sprintf("ret %s\n", r.op)
+	return fmt.Sprintf("ret %s\n", r.Op)
 }
 func (r *Ret) instruction() {}
 

ttir/ttir_test.go

@@ -85,7 +85,7 @@ func expectInstruction(t *testing.T, inst Instruction, actual Instruction) {
 			return
 		}
 
-		expectOperand(t, inst.op, ret.op)
+		expectOperand(t, inst.Op, ret.Op)
 	}
 }
 
@@ -116,7 +116,7 @@ func TestBasicFunction(t *testing.T) {
 					Name: "main",
 					Instructions: []Instruction{
 						&Ret{
-							op: &Constant{Value: 0},
+							Op: &Constant{Value: 0},
 						},
 					},
 				},

typechecker/checker.go

@@ -9,7 +9,9 @@ import (
 	"robaertschi.xyz/robaertschi/tt/token"
 )
 
-type Checker struct{}
+type Checker struct {
+	foundMain bool
+}
 
 func New() *Checker {
 	return &Checker{}
@@ -32,6 +34,11 @@ func (c *Checker) CheckProgram(program *ast.Program) (*tast.Program, error) {
 		}
 	}
 
+	if !c.foundMain {
+		// TODO: Add support for libraries
+		errs = append(errs, errors.New("no function called 'main' found"))
+	}
+
 	return &tast.Program{Declarations: decls}, errors.Join(errs...)
 }
 
@@ -44,6 +51,10 @@ func (c *Checker) checkDeclaration(decl ast.Declaration) (tast.Declaration, erro
 			return nil, err
 		}
 
+		if decl.Name == "main" {
+			c.foundMain = true
+		}
+
 		return &tast.FunctionDeclaration{Token: decl.Token, Body: body, ReturnType: body.Type(), Name: decl.Name}, nil
 	}
 	return nil, errors.New("unhandled declaration in type checker")