From a03115eff7ee03f978e351e50ebc9dc7ba66b233 Mon Sep 17 00:00:00 2001
From: xushiwei <x@goplus.org>
Date: Sun, 3 Apr 2022 15:45:45 +0800
Subject: [PATCH] union: support embedded field

---
 cl/codebuild.go        | 37 ++++++++++++++++++++++++++++++-------
 cl/type_and_var.go     |  1 +
 testdata/union/union.c | 19 ++++++++++++++++++-
 3 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/cl/codebuild.go b/cl/codebuild.go
index b5c5545..e5b7bf9 100644
--- a/cl/codebuild.go
+++ b/cl/codebuild.go
@@ -42,18 +42,42 @@ func newUnionBuilder() *unionBuilder {
 	return &unionBuilder{}
 }
 
+func unionEmbeddedField(ctx *blockCtx, fields []*gox.UnionField, t *types.Named, off int) []*gox.UnionField {
+	o := t.Underlying().(*types.Struct)
+	for i, n := 0, o.NumFields(); i < n; i++ {
+		fld := o.Field(i)
+		fldType := fld.Type()
+		if fld.Embedded() {
+			fields = unionEmbeddedField(ctx, fields, fldType.(*types.Named), off)
+		} else {
+			fields = append(fields, &gox.UnionField{
+				Name: fld.Name(),
+				Off:  off,
+				Type: fldType,
+			})
+		}
+		off += ctx.sizeof(fldType)
+	}
+	return fields
+}
+
 func (p *unionBuilder) Type(ctx *blockCtx, t *types.Named) *types.Struct {
 	var fldLargest *gox.UnionField
-	var lenLargest int
-	for _, fld := range p.fields {
+	var fields = p.fields
+	var lenLargest, n = 0, len(fields)
+	for i := 0; i < n; i++ {
+		fld := fields[i]
 		if len := ctx.sizeof(fld.Type); len > lenLargest {
 			fldLargest, lenLargest = fld, len
 		}
+		if fld.Name == "" { // embedded
+			fields = unionEmbeddedField(ctx, fields, fld.Type.(*types.Named), 0)
+		}
 	}
 	flds := make([]*types.Var, 0, 1)
 	if fldLargest != nil {
 		pkg := ctx.pkg
-		pkg.SetVFields(t, gox.NewUnionFields(p.fields))
+		pkg.SetVFields(t, gox.NewUnionFields(fields))
 		fld := types.NewField(fldLargest.Pos, pkg.Types, fldLargest.Name, fldLargest.Type, false)
 		flds = append(flds, fld)
 	}
@@ -61,16 +85,15 @@ func (p *unionBuilder) Type(ctx *blockCtx, t *types.Named) *types.Struct {
 }
 
 func (p *unionBuilder) Field(ctx *blockCtx, pos token.Pos, typ types.Type, name string, embedded bool) {
+	if embedded {
+		name = ""
+	}
 	fld := &gox.UnionField{
 		Name: name,
-		Off:  0, // TODO
 		Type: typ,
 		Pos:  pos,
 	}
 	p.fields = append(p.fields, fld)
-	if name == "" {
-		log.Fatalln("unionBuilder.Field TODO: embedded")
-	}
 }
 
 // -----------------------------------------------------------------------------
diff --git a/cl/type_and_var.go b/cl/type_and_var.go
index 29b4ebb..0605216 100644
--- a/cl/type_and_var.go
+++ b/cl/type_and_var.go
@@ -114,6 +114,7 @@ func toUnionType(ctx *blockCtx, t *types.Named, unio *ast.Node, ns string) types
 				}
 				break
 			}
+		case ast.IndirectFieldDecl:
 		default:
 			log.Fatalln("toUnionType: unknown field kind =", decl.Kind)
 		}
diff --git a/testdata/union/union.c b/testdata/union/union.c
index b558354..332d172 100644
--- a/testdata/union/union.c
+++ b/testdata/union/union.c
@@ -1,11 +1,17 @@
 #include <stdio.h>
 
 typedef union {
-    long a;
+    int a;
     unsigned short b;
     struct bar {
         unsigned short low, high;
     } c;
+    struct {
+        unsigned short low;
+        struct {
+            unsigned short high;
+        };
+    };
 } foo;
 
 int main() {
@@ -16,5 +22,16 @@ int main() {
     printf(
         "foo.a = %d, foo.b = %d, foo.c.low = %d, foo.c.high = %d\n",
         foo.a, foo.b, foo.c.low, foo.c.high);
+    printf(
+        "foo.low = %d, foo.high = %d\n",
+        foo.low, foo.high);
+    foo.low = 5;
+    foo.high = 6;
+    printf(
+        "foo.a = %d, foo.b = %d, foo.c.low = %d, foo.c.high = %d\n",
+        foo.a, foo.b, foo.c.low, foo.c.high);
+    printf(
+        "foo.low = %d, foo.high = %d\n",
+        foo.low, foo.high);
     return 0;
 }