cmd/cgo, misc/cgo: only cache anonymous struct typedefs with parent name

CL 181857 broke the translation of certain C types using cmd/cgo -godefs
because it stores each typedef, array and qualified type with their
parent type name in the translation cache.

Fix this by only considering the parent type for typedefs of anonymous
structs which is the only case where types might become ambiguous.

Updates #31891
Fixes #37479
Fixes #37621

Change-Id: I301a749ec89585789cb0d213593bb8b7341beb88
Reviewed-on: https://go-review.googlesource.com/c/go/+/226341
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

4 files changed, 66 insertions, 0 deletions

diff --git a/misc/cgo/testgodefs/testdata/issue37479.go b/misc/cgo/testgodefs/testdata/issue37479.go
new file mode 100644
index 0000000000..a210eb5bc5
--- /dev/null
+++ b/misc/cgo/testgodefs/testdata/issue37479.go
@@ -0,0 +1,33 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// +build ignore
+
+package main
+
+/*
+typedef struct A A;
+
+typedef struct {
+	struct A *next;
+	struct A **prev;
+} N;
+
+struct A
+{
+	N n;
+};
+
+typedef struct B
+{
+	A* a;
+} B;
+*/
+import "C"
+
+type N C.N
+
+type A C.A
+
+type B C.B
diff --git a/misc/cgo/testgodefs/testdata/issue37621.go b/misc/cgo/testgodefs/testdata/issue37621.go
new file mode 100644
index 0000000000..d5ace3f6d6
--- /dev/null
+++ b/misc/cgo/testgodefs/testdata/issue37621.go
@@ -0,0 +1,23 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// +build ignore
+
+package main
+
+/*
+struct tt {
+	long long a;
+	long long b;
+};
+
+struct s {
+	struct tt ts[3];
+};
+*/
+import "C"
+
+type TT C.struct_tt
+
+type S C.struct_s
diff --git a/misc/cgo/testgodefs/testdata/main.go b/misc/cgo/testgodefs/testdata/main.go
index 1ce0fd0d1e..ef45b95e65 100644
--- a/misc/cgo/testgodefs/testdata/main.go
+++ b/misc/cgo/testgodefs/testdata/main.go
@@ -11,5 +11,13 @@ var v2 = v1.L
 // Test that P, Q, and R all point to byte.
 var v3 = Issue8478{P: (*byte)(nil), Q: (**byte)(nil), R: (***byte)(nil)}
 
+// Test that N, A and B are fully defined
+var v4 = N{}
+var v5 = A{}
+var v6 = B{}
+
+// Test that S is fully defined
+var v7 = S{}
+
 func main() {
 }
diff --git a/misc/cgo/testgodefs/testgodefs_test.go b/misc/cgo/testgodefs/testgodefs_test.go
index c02c3ff0ac..438d23d65c 100644
--- a/misc/cgo/testgodefs/testgodefs_test.go
+++ b/misc/cgo/testgodefs/testgodefs_test.go
@@ -21,6 +21,8 @@ var filePrefixes = []string{
 	"anonunion",
 	"issue8478",
 	"fieldtypedef",
+	"issue37479",
+	"issue37621",
 }
 
 func TestGoDefs(t *testing.T) {