btf: Handle Tags when making copies

d4b2f8c introduced Tags on different types implementing btf.Type. Tags arrays are initialized at load time from declTag-s referring to the respective type. Type-s are explicitly copied with btf.Copy, also implicitly when copying a btf.Spec. Semantically, it is a deep copy, hence Tags must be cloned as well. Signed-off-by: Nick Zavaritsky <[email protected]>
cilium · Oct 10, 2024 · c63a00b · c63a00b
1 parent d6606c0
commit c63a00b
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Showing 2 changed files with 30 additions and 0 deletions.
diff --git a/btf/types.go b/btf/types.go
@@ -183,6 +183,7 @@ func (s *Struct) size() uint32 { return s.Size }
 func (s *Struct) copy() Type {
 	cpy := *s
 	cpy.Members = copyMembers(s.Members)
+	cpy.Tags = copyTags(cpy.Tags)
 	return &cpy
 }
 
@@ -210,6 +211,7 @@ func (u *Union) size() uint32 { return u.Size }
 func (u *Union) copy() Type {
 	cpy := *u
 	cpy.Members = copyMembers(u.Members)
+	cpy.Tags = copyTags(cpy.Tags)
 	return &cpy
 }
 
@@ -220,6 +222,18 @@ func (u *Union) members() []Member {
 func copyMembers(orig []Member) []Member {
 	cpy := make([]Member, len(orig))
 	copy(cpy, orig)
+	for i, member := range cpy {
+		cpy[i].Tags = copyTags(member.Tags)
+	}
+	return cpy
+}
+
+func copyTags(orig []string) []string {
+	if orig == nil { // preserve nil vs zero-len slice distinction
+		return nil
+	}
+	cpy := make([]string, len(orig))
+	copy(cpy, orig)
 	return cpy
 }
 
@@ -348,6 +362,7 @@ func (td *Typedef) TypeName() string { return td.Name }
 
 func (td *Typedef) copy() Type {
 	cpy := *td
+	cpy.Tags = copyTags(td.Tags)
 	return &cpy
 }
 
@@ -434,6 +449,14 @@ func (f *Func) TypeName() string { return f.Name }
 
 func (f *Func) copy() Type {
 	cpy := *f
+	cpy.Tags = copyTags(f.Tags)
+	if f.ParamTags != nil { // preserve nil vs zero-len slice distinction
+		ptCopy := make([][]string, len(f.ParamTags))
+		for i, tags := range f.ParamTags {
+			ptCopy[i] = copyTags(tags)
+		}
+		cpy.ParamTags = ptCopy
+	}
 	return &cpy
 }
 
@@ -477,6 +500,7 @@ func (v *Var) TypeName() string { return v.Name }
 
 func (v *Var) copy() Type {
 	cpy := *v
+	cpy.Tags = copyTags(v.Tags)
 	return &cpy
 }
 

diff --git a/btf/types_test.go b/btf/types_test.go
@@ -42,6 +42,7 @@ func TestSizeof(t *testing.T) {
 
 func TestCopy(t *testing.T) {
 	i := &Int{Size: 4}
+	tags := []string{"bar:foo"}
 
 	got := Copy(&Struct{
 		Members: []Member{
@@ -60,6 +61,11 @@ func TestCopy(t *testing.T) {
 		{"void", (*Void)(nil)},
 		{"int", i},
 		{"cyclical", newCyclicalType(2)},
+		{"struct tags", &Struct{Tags: tags, Members: []Member{{Tags: tags}}}},
+		{"union tags", &Union{Tags: tags, Members: []Member{{Tags: tags}}}},
+		{"typedef tags", &Typedef{Type: i, Tags: tags}},
+		{"var tags", &Var{Type: i, Tags: tags}},
+		{"func tags", &Func{Tags: tags, ParamTags: [][]string{tags}}},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			cpy := Copy(test.typ)