prog: parse comments in serialized programs

Remember per-call comments, will be useful for annotating tests.
Also support this form:
call() # comment

3 files changed, 53 insertions, 7 deletions

diff --git a/prog/encoding.go b/prog/encoding.go
index f0d96da95..8c853fa4a 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -9,6 +9,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"strconv"
+	"strings"
 )
 
 // String generates a very compact program description (mostly for debug output).
@@ -156,8 +157,14 @@ func (target *Target) Deserialize(data []byte) (prog *Prog, err error) {
 	}
 	p := newParser(data)
 	vars := make(map[string]*ResultArg)
+	comment := ""
 	for p.Scan() {
-		if p.EOF() || p.Char() == '#' {
+		if p.EOF() {
+			comment = ""
+			continue
+		}
+		if p.Char() == '#' {
+			comment = strings.TrimSpace(p.s[p.i+1:])
 			continue
 		}
 		name := p.Ident()
@@ -173,8 +180,9 @@ func (target *Target) Deserialize(data []byte) (prog *Prog, err error) {
 			return nil, fmt.Errorf("unknown syscall %v", name)
 		}
 		c := &Call{
-			Meta: meta,
-			Ret:  MakeReturnArg(meta.Ret),
+			Meta:    meta,
+			Ret:     MakeReturnArg(meta.Ret),
+			Comment: comment,
 		}
 		prog.Calls = append(prog.Calls, c)
 		p.Parse('(')
@@ -197,8 +205,12 @@ func (target *Target) Deserialize(data []byte) (prog *Prog, err error) {
 			}
 		}
 		p.Parse(')')
+		p.SkipWs()
 		if !p.EOF() {
-			return nil, fmt.Errorf("tailing data (line #%v)", p.l)
+			if p.Char() != '#' {
+				return nil, fmt.Errorf("tailing data (line #%v)", p.l)
+			}
+			c.Comment = strings.TrimSpace(p.s[p.i+1:])
 		}
 		for i := len(c.Args); i < len(meta.Args); i++ {
 			c.Args = append(c.Args, target.defaultArg(meta.Args[i]))
@@ -209,6 +221,7 @@ func (target *Target) Deserialize(data []byte) (prog *Prog, err error) {
 		if r != "" && c.Ret != nil {
 			vars[r] = c.Ret
 		}
+		comment = ""
 	}
 	if err := p.Err(); err != nil {
 		return nil, err
diff --git a/prog/encoding_test.go b/prog/encoding_test.go
index c641fd5e6..7ecd811bc 100644
--- a/prog/encoding_test.go
+++ b/prog/encoding_test.go
@@ -303,3 +303,35 @@ func testSerializeDeserialize(t *testing.T, p0 *Prog, data0, data1 []byte) (bool
 	}
 	return true, 0, 0
 }
+
+func TestDeserializeComments(t *testing.T) {
+	target := initTargetTest(t, "test", "64")
+	p, err := target.Deserialize([]byte(`
+# comment1
+# comment2
+serialize0()
+serialize0()
+# comment3
+serialize0()
+# comment4
+serialize0()	#  comment5
+#comment6
+
+serialize0()
+#comment7
+`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i, want := range []string{
+		"comment2",
+		"",
+		"comment3",
+		"comment5",
+		"",
+	} {
+		if got := p.Calls[i].Comment; got != want {
+			t.Errorf("bad call %v comment: %q, want %q", i, got, want)
+		}
+	}
+}
diff --git a/prog/prog.go b/prog/prog.go
index 19db1893d..95f95ad27 100644
--- a/prog/prog.go
+++ b/prog/prog.go
@@ -13,9 +13,10 @@ type Prog struct {
 }
 
 type Call struct {
-	Meta *Syscall
-	Args []Arg
-	Ret  *ResultArg
+	Meta    *Syscall
+	Args    []Arg
+	Ret     *ResultArg
+	Comment string
 }
 
 type Arg interface {