From 291192c61b4d6bad6c11e8732be7de26f1add0ef Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Mon, 4 Sep 2017 19:52:57 +0200
Subject: [PATCH] pkg/compiler: don't allow bitfields in unions, args and anon
 types

---
 pkg/compiler/check.go            | 24 +++++++++++++++---------
 pkg/compiler/testdata/errors.txt | 10 ++++++++--
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/pkg/compiler/check.go b/pkg/compiler/check.go
index 5a3dea45..f75c0276 100644
--- a/pkg/compiler/check.go
+++ b/pkg/compiler/check.go
@@ -146,18 +146,18 @@ func (comp *compiler) checkTypes() {
 	for _, decl := range comp.desc.Nodes {
 		switch n := decl.(type) {
 		case *ast.Resource:
-			comp.checkType(n.Base, false, false, true)
+			comp.checkType(n.Base, false, false, false, true)
 		case *ast.Struct:
 			for _, f := range n.Fields {
-				comp.checkType(f.Type, false, false, false)
+				comp.checkType(f.Type, false, false, !n.IsUnion, false)
 			}
 			comp.checkStruct(n)
 		case *ast.Call:
 			for _, a := range n.Args {
-				comp.checkType(a.Type, true, false, false)
+				comp.checkType(a.Type, true, false, false, false)
 			}
 			if n.Ret != nil {
-				comp.checkType(n.Ret, true, true, false)
+				comp.checkType(n.Ret, true, true, false, false)
 			}
 		}
 	}
@@ -394,7 +394,7 @@ func (comp *compiler) checkStruct(n *ast.Struct) {
 	}
 }
 
-func (comp *compiler) checkType(t *ast.Type, isArg, isRet, isResourceBase bool) {
+func (comp *compiler) checkType(t *ast.Type, isArg, isRet, isStruct, isResourceBase bool) {
 	if unexpected, _, ok := checkTypeKind(t, kindIdent); !ok {
 		comp.error(t.Pos, "unexpected %v, expect type", unexpected)
 		return
@@ -404,9 +404,15 @@ func (comp *compiler) checkType(t *ast.Type, isArg, isRet, isResourceBase bool)
 		comp.error(t.Pos, "unknown type %v", t.Ident)
 		return
 	}
-	if t.HasColon && (!desc.AllowColon || isArg) {
-		comp.error(t.Pos2, "unexpected ':'")
-		return
+	if t.HasColon {
+		if !desc.AllowColon {
+			comp.error(t.Pos2, "unexpected ':'")
+			return
+		}
+		if !isStruct {
+			comp.error(t.Pos2, "unexpected ':', only struct fields can be bitfields")
+			return
+		}
 	}
 	if isRet && (!desc.CanBeArg || desc.CantBeRet) {
 		comp.error(t.Pos, "%v can't be syscall return", t.Ident)
@@ -448,7 +454,7 @@ func (comp *compiler) checkType(t *ast.Type, isArg, isRet, isResourceBase bool)
 	err0 := comp.errors
 	for i, arg := range args {
 		if desc.Args[i].Type == typeArgType {
-			comp.checkType(arg, false, isRet, false)
+			comp.checkType(arg, false, isRet, false, false)
 		} else {
 			comp.checkTypeArg(t, arg, desc.Args[i])
 		}
diff --git a/pkg/compiler/testdata/errors.txt b/pkg/compiler/testdata/errors.txt
index dc535b00..512d615c 100644
--- a/pkg/compiler/testdata/errors.txt
+++ b/pkg/compiler/testdata/errors.txt
@@ -63,7 +63,7 @@ sf2 = "a", "b"
 sf2 = "c"			### string flags sf2 redeclared, previously declared at errors.txt:62:1
 
 resource r2[r0]: 2
-resource r3[int32:1]
+resource r3[int32:1]		###  unexpected ':', only struct fields can be bitfields
 resource r4[int32[opt]]		### resource base can't be marked as opt
 resource r5[non_existent]	### unknown type non_existent
 resource r9["foo"]		### unexpected string "foo", expect type
@@ -108,7 +108,8 @@ foo$43(a ptr[in, string[1]])	### unexpected int 1, string arg must be a string l
 foo$44(a int32) len[a]		### len can't be syscall return
 foo$45(a int32) len[b]		### len can't be syscall return
 foo$46(a ptr[in, in])		### unknown type in
-foo$47(a int32:2)		### unexpected ':'
+foo$47(a int32:2)		### unexpected ':', only struct fields can be bitfields
+foo$48(a ptr[in, int32:7])	### unexpected ':', only struct fields can be bitfields
 
 opt {				### struct uses reserved name opt
 	f1	int32
@@ -162,6 +163,11 @@ u4 [
 	f2	int32
 ] [packed]			### unknown union u4 attribute packed
 
+u5 [
+	f1	int8:1		### unexpected ':', only struct fields can be bitfields
+	f2	int8:2		### unexpected ':', only struct fields can be bitfields
+]
+
 define d0 SOMETHING
 define d1 `some C expression`
 define d2 some C expression