compiler,reflect: fix pkgpath for struct fields

compiler/interface.go

@@ -84,6 +84,27 @@ func (b *builder) extractValueFromInterface(itf llvm.Value, llvmType llvm.Type)
 	return b.emitPointerUnpack(valuePtr, []llvm.Type{llvmType})[0]
 }
 
+func (c *compilerContext) pkgPathPtr(pkgpath string) llvm.Value {
+	pkgpathName := "reflect/types.type.pkgpath.empty"
+	if pkgpath != "" {
+		pkgpathName = "reflect/types.type.pkgpath:" + pkgpath
+	}
+
+	pkgpathInitializer := c.ctx.ConstString(pkgpath+"\x00", false)
+	pkgpathGlobal := llvm.AddGlobal(c.mod, pkgpathInitializer.Type(), pkgpathName)
+	pkgpathGlobal.SetInitializer(pkgpathInitializer)
+	pkgpathGlobal.SetAlignment(1)
+	pkgpathGlobal.SetUnnamedAddr(true)
+	pkgpathGlobal.SetLinkage(llvm.LinkOnceODRLinkage)
+	pkgpathGlobal.SetGlobalConstant(true)
+	pkgPathPtr := llvm.ConstGEP(pkgpathGlobal.GlobalValueType(), pkgpathGlobal, []llvm.Value{
+		llvm.ConstInt(c.ctx.Int32Type(), 0, false),
+		llvm.ConstInt(c.ctx.Int32Type(), 0, false),
+	})
+
+	return pkgPathPtr
+}
+
 // getTypeCode returns a reference to a type code.
 // A type code is a pointer to a constant global that describes the type.
 // This function returns a pointer to the 'kind' field (which might not be the
@@ -141,6 +162,7 @@ func (c *compilerContext) getTypeCode(typ types.Type) llvm.Value {
 			typeFieldTypes = append(typeFieldTypes,
 				types.NewVar(token.NoPos, nil, "numFields", types.Typ[types.Uint16]),
 				types.NewVar(token.NoPos, nil, "ptrTo", types.Typ[types.UnsafePointer]),
+				types.NewVar(token.NoPos, nil, "pkgpath", types.Typ[types.UnsafePointer]),
 				types.NewVar(token.NoPos, nil, "fields", types.NewArray(c.getRuntimeType("structField"), int64(typ.NumFields()))),
 			)
 		case *types.Interface:
@@ -173,31 +195,15 @@ func (c *compilerContext) getTypeCode(typ types.Type) llvm.Value {
 			typeFields = []llvm.Value{c.getTypeCode(types.NewPointer(typ))}
 		case *types.Named:
 			name := typ.Obj().Name()
-
-			pkg := typ.Obj().Pkg()
 			var pkgpath string
-			pkgpathName := "reflect/types.type.pkgpath.empty"
+			if pkg := typ.Obj().Pkg(); pkg != nil {
-			if pkg != nil {
 				pkgpath = pkg.Path()
-				pkgpathName = "reflect/types.type.pkgpath:" + pkgpath
 			}
-
+			pkgPathPtr := c.pkgPathPtr(pkgpath)
-			pkgpathInitializer := c.ctx.ConstString(pkgpath+"\x00", false)
-			pkgpathGlobal := llvm.AddGlobal(c.mod, pkgpathInitializer.Type(), pkgpathName)
-			pkgpathGlobal.SetInitializer(pkgpathInitializer)
-			pkgpathGlobal.SetAlignment(1)
-			pkgpathGlobal.SetUnnamedAddr(true)
-			pkgpathGlobal.SetLinkage(llvm.LinkOnceODRLinkage)
-			pkgpathGlobal.SetGlobalConstant(true)
-			pkgpathPtr := llvm.ConstGEP(pkgpathGlobal.GlobalValueType(), pkgpathGlobal, []llvm.Value{
-				llvm.ConstInt(c.ctx.Int32Type(), 0, false),
-				llvm.ConstInt(c.ctx.Int32Type(), 0, false),
-			})
-
 			typeFields = []llvm.Value{
 				c.getTypeCode(types.NewPointer(typ)),  // ptrTo
 				c.getTypeCode(typ.Underlying()),       // underlying
-				pkgpathPtr,                            // pkgpath pointer
+				pkgPathPtr,                            // pkgpath pointer
 				c.ctx.ConstString(name+"\x00", false), // name
 			}
 			metabyte |= 1 << 5 // "named" flag
@@ -226,9 +232,18 @@ func (c *compilerContext) getTypeCode(typ types.Type) llvm.Value {
 				c.getTypeCode(typ.Key()),             // key
 			}
 		case *types.Struct:
+			var pkgpath string
+			if typ.NumFields() > 0 {
+				if pkg := typ.Field(0).Pkg(); pkg != nil {
+					pkgpath = pkg.Path()
+				}
+			}
+			pkgPathPtr := c.pkgPathPtr(pkgpath)
+
 			typeFields = []llvm.Value{
 				llvm.ConstInt(c.ctx.Int16Type(), uint64(typ.NumFields()), false), // numFields
 				c.getTypeCode(types.NewPointer(typ)),                             // ptrTo
+				pkgPathPtr,
 			}
 			structFieldType := c.getLLVMRuntimeType("structField")
 			var fields []llvm.Value

src/reflect/type.go

@@ -39,6 +39,7 @@
 //     meta         uint8
 //     numField     uint16
 //     ptrTo        *typeStruct
+//     pkgpath      *byte
 //     fields       [...]structField // the remaining fields are all of type structField
 // - interface types (this is missing the interface methods):
 //     meta         uint8
@@ -444,6 +445,7 @@ type structType struct {
 	rawType
 	numField uint16
 	ptrTo    *rawType
+	pkgpath  *byte
 	fields   [1]structField // the remaining fields are all of type structField
 }
 
@@ -576,7 +578,7 @@ func (t *rawType) Field(i int) StructField {
 	}
 }
 
-func rawStructFieldFromPointer(fieldType *rawType, data unsafe.Pointer, flagsByte uint8, name string, offset uintptr) rawStructField {
+func rawStructFieldFromPointer(descriptor *structType, fieldType *rawType, data unsafe.Pointer, flagsByte uint8, name string, offset uintptr) rawStructField {
 	// Read the field tag, if there is one.
 	var tag string
 	if flagsByte&structFieldFlagHasTag != 0 {
@@ -594,7 +596,7 @@ func rawStructFieldFromPointer(fieldType *rawType, data unsafe.Pointer, flagsByt
 	pkgPath := ""
 	if flagsByte&structFieldFlagIsExported == 0 {
 		// This field is unexported.
-		pkgPath = fieldType.PkgPath()
+		pkgPath = readStringZ(unsafe.Pointer(descriptor.pkgpath))
 	}
 
 	return rawStructField{
@@ -646,7 +648,7 @@ func (t *rawType) rawField(n int) rawStructField {
 	name := readStringZ(data)
 	data = unsafe.Add(data, len(name))
 
-	return rawStructFieldFromPointer(field.fieldType, data, flagsByte, name, offset)
+	return rawStructFieldFromPointer(descriptor, field.fieldType, data, flagsByte, name, offset)
 }
 
 // rawFieldByName returns nearly the same value as FieldByName but without converting the
@@ -696,7 +698,7 @@ func (t *rawType) rawFieldByName(n string) (rawStructField, []int, bool) {
 				data = unsafe.Add(data, len(name))
 				if name == n {
 					found = append(found, result{
-						rawStructFieldFromPointer(field.fieldType, data, flagsByte, name, offset),
+						rawStructFieldFromPointer(descriptor, field.fieldType, data, flagsByte, name, offset),
 						append(ll.index, int(i)),
 					})
 				}

testdata/reflect.go

@@ -481,6 +481,7 @@ func showValue(rv reflect.Value, indent string) {
 		for i := 0; i < rv.NumField(); i++ {
 			field := rt.Field(i)
 			println(indent+"  field:", i, field.Name)
+			println(indent+"  pkg:", field.PkgPath)
 			println(indent+"  tag:", strconv.Quote(string(field.Tag)))
 			println(indent+"  embedded:", field.Anonymous)
 			println(indent+"  exported:", field.IsExported())

testdata/reflect.txt

@@ -233,6 +233,7 @@ reflect type: struct
 reflect type: struct
   struct: 1
   field: 0 error
+  pkg: main
   tag: ""
   embedded: true
   exported: false
@@ -242,18 +243,21 @@ reflect type: struct
 reflect type: struct
   struct: 3
   field: 0 a
+  pkg: main
   tag: ""
   embedded: false
   exported: false
   reflect type: uint8 caninterface=false
     uint: 42
   field: 1 b
+  pkg: main
   tag: ""
   embedded: false
   exported: false
   reflect type: int16 caninterface=false
     int: 321
   field: 2 c
+  pkg: main
   tag: ""
   embedded: false
   exported: false
@@ -262,36 +266,42 @@ reflect type: struct
 reflect type: struct comparable=false
   struct: 5
   field: 0 n
+  pkg: main
   tag: "foo:\"bar\""
   embedded: false
   exported: false
   reflect type: int caninterface=false
     int: 5
   field: 1 some
+  pkg: main
   tag: "some\x00tag"
   embedded: false
   exported: false
   reflect type: struct caninterface=false
     struct: 2
     field: 0 X
+    pkg: 
     tag: ""
     embedded: false
     exported: true
     reflect type: int16 caninterface=false
       int: -5
     field: 1 Y
+    pkg: 
     tag: ""
     embedded: false
     exported: true
     reflect type: int16 caninterface=false
       int: 3
   field: 2 zero
+  pkg: main
   tag: ""
   embedded: false
   exported: false
   reflect type: struct caninterface=false
     struct: 0
   field: 3 buf
+  pkg: main
   tag: ""
   embedded: false
   exported: false
@@ -306,6 +316,7 @@ reflect type: struct comparable=false
     reflect type: uint8 addrable=true caninterface=false
       uint: 111
   field: 4 Buf
+  pkg: 
   tag: ""
   embedded: false
   exported: true
@@ -322,6 +333,7 @@ reflect type: ptr
   reflect type: struct settable=true addrable=true
     struct: 2
     field: 0 next
+    pkg: main
     tag: "description:\"chain\""
     embedded: false
     exported: false
@@ -329,6 +341,7 @@ reflect type: ptr
       pointer: false struct
       nil: true
     field: 1 foo
+    pkg: main
     tag: ""
     embedded: false
     exported: false
@@ -337,12 +350,14 @@ reflect type: ptr
 reflect type: struct
   struct: 2
   field: 0 A
+  pkg: 
   tag: ""
   embedded: false
   exported: true
   reflect type: uintptr
     uint: 2
   field: 1 B
+  pkg: 
   tag: ""
   embedded: false
   exported: true