feat(verify): add universal --ground-truth verification against go tool asm

Assisted-by: Qwen 3.8 Max Preview

verify/groundtruth_test.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+package verify
+
+import (
+	"testing"
+)
+
+func TestGroundTruthBasic(t *testing.T) {
+	// Use the simple test kernel — it assembles with go tool asm.
+	gt, err := GroundTruth("../testdata/verify/basic_amd64.s")
+	if err != nil {
+		t.Fatalf("GroundTruth: %v", err)
+	}
+	if len(gt) == 0 {
+		t.Fatal("no functions extracted from ground truth")
+	}
+	// The "add" function should be present and non-empty.
+	code, ok := gt["add"]
+	if !ok {
+		t.Fatalf("function 'add' not found in ground truth; got: %v", keys(gt))
+	}
+	if len(code) == 0 {
+		t.Fatal("add: zero-length code")
+	}
+	t.Logf("ground truth functions: %v", keys(gt))
+}
+
+func TestGroundTruthComparison(t *testing.T) {
+	// Assemble with gasm and compare against go tool asm.
+	k, err := Load("../testdata/verify/basic_amd64.s")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	defer k.Close()
+
+	gt, err := GroundTruth("../testdata/verify/basic_amd64.s")
+	if err != nil {
+		t.Fatalf("GroundTruth: %v", err)
+	}
+
+	for _, name := range k.FuncNames() {
+		fl, _ := k.Func(name)
+		gasmCode := k.Image().Code[fl.Offset : fl.Offset+fl.Size]
+		goCode, ok := gt[name]
+		if !ok {
+			t.Errorf("%s: not in ground truth", name)
+			continue
+		}
+		if len(gasmCode) != len(goCode) {
+			t.Errorf("%s: size mismatch: gasm=%d go=%d", name, len(gasmCode), len(goCode))
+			continue
+		}
+		for i := range gasmCode {
+			if gasmCode[i] != goCode[i] {
+				t.Errorf("%s: byte %d differs: gasm=%02x go=%02x", name, i, gasmCode[i], goCode[i])
+				break
+			}
+		}
+	}
+}
+
+func TestGroundTruthBadFile(t *testing.T) {
+	_, err := GroundTruth("/nonexistent/file_amd64.s")
+	if err == nil {
+		t.Fatal("expected error for nonexistent file")
+	}
+}
+
+func keys(m map[string][]byte) []string {
+	out := make([]string, 0, len(m))
+	for k := range m {
+		out = append(out, k)
+	}
+	return out
+}