generate the instruction table

internal/gen/asmtest.go

@@ -10,18 +10,21 @@ import (
 )
 
 type asmtest struct {
+	cfg   Config
 	sym   string // reference to the test function symbol
 	rel8  string // label to be used for near jumps
 	rel32 string // label for far jumps
 }
 
-func NewAsmTest() Interface {
-	return &asmtest{}
+func NewAsmTest(cfg Config) Interface {
+	return &asmtest{cfg: cfg}
 }
 
 func (a *asmtest) Generate(is []*inst.Instruction) ([]byte, error) {
 	p := &printer{}
 
+	p.Printf("# %s\n\n", a.cfg.GeneratedWarning())
+
 	a.sym = "\u00b7loadertest(SB)"
 	p.Printf("TEXT %s, 0, $0\n", a.sym)
 

internal/gen/gen.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/format"
+	"strings"
 
 	"github.com/mmcloughlin/avo/internal/inst"
 )
@@ -18,6 +19,24 @@ func (f Func) Generate(is []*inst.Instruction) ([]byte, error) {
 	return f(is)
 }
 
+type Config struct {
+	Name string
+	Argv []string
+}
+
+func (c Config) GeneratedBy() string {
+	if c.Argv == nil {
+		return c.Name
+	}
+	return fmt.Sprintf("command: %s", strings.Join(c.Argv, " "))
+}
+
+func (c Config) GeneratedWarning() string {
+	return fmt.Sprintf("Code generated by %s. DO NOT EDIT.", c.GeneratedBy())
+}
+
+type Builder func(Config) Interface
+
 // GoFmt formats Go code produced from the given generator.
 func GoFmt(i Interface) Interface {
 	return Func(func(is []*inst.Instruction) ([]byte, error) {

internal/gen/gen_test.go

@@ -0,0 +1,8 @@
+package gen
+
+import "testing"
+
+func TestBuilderInterfaces(t *testing.T) {
+	var _ Builder = NewAsmTest
+	var _ Builder = NewGoData
+}

internal/gen/godata.go

@@ -5,15 +5,17 @@ import (
 )
 
 type godata struct {
+	cfg Config
 }
 
-func NewGoData() Interface {
-	return GoFmt(godata{})
+func NewGoData(cfg Config) Interface {
+	return GoFmt(godata{cfg: cfg})
 }
 
 func (g godata) Generate(is []*inst.Instruction) ([]byte, error) {
 	p := &printer{}
 
+	p.Printf("// %s\n\n", g.cfg.GeneratedWarning())
 	p.Printf("package inst\n\n")
 
 	p.Printf("var Instructions = []Instruction{\n")