sys: change BitfieldLast to BitfieldMiddle

That's the condition we always want.
Currently we always check:
t.BitfieldOffset() == 0 || t.BitfieldLast()
now can check just:
!t.BitfieldMiddle()

6 files changed, 290 insertions, 298 deletions

diff --git a/sys/decl.go b/sys/decl.go
index 1a474616f..077023cf2 100644
--- a/sys/decl.go
+++ b/sys/decl.go
@@ -34,7 +34,7 @@ type Type interface {
 	Size() uint64
 	BitfieldOffset() uint64
 	BitfieldLength() uint64
-	BitfieldLast() bool
+	BitfieldMiddle() bool // returns true for all but last bitfield in a group
 }
 
 func IsPad(t Type) bool {
@@ -87,7 +87,7 @@ func (t *TypeCommon) BitfieldLength() uint64 {
 	return 0
 }
 
-func (t *TypeCommon) BitfieldLast() bool {
+func (t *TypeCommon) BitfieldMiddle() bool {
 	return false
 }
 
@@ -124,15 +124,7 @@ type IntTypeCommon struct {
 	BitfieldOff uint64
 	BitfieldLen uint64
 	BigEndian   bool
-	BitfieldLst bool
-}
-
-func (t *IntTypeCommon) Size() uint64 {
-	// TODO(dvyukov): check that this is not a middle bitfield
-	// if t.BitfieldLen != 0 && !t.BitfieldLst {
-	//	panic(fmt.Sprintf("bitfields don't have size: %#v", t))
-	// }
-	return t.TypeCommon.Size()
+	BitfieldMdl bool
 }
 
 func (t *IntTypeCommon) BitfieldOffset() uint64 {
@@ -143,8 +135,8 @@ func (t *IntTypeCommon) BitfieldLength() uint64 {
 	return t.BitfieldLen
 }
 
-func (t *IntTypeCommon) BitfieldLast() bool {
-	return t.BitfieldLst
+func (t *IntTypeCommon) BitfieldMiddle() bool {
+	return t.BitfieldMdl
 }
 
 type ConstType struct {
diff --git a/sys/sys_386.go b/sys/sys_386.go
index e4d4498fa..54ac7e250 100644
--- a/sys/sys_386.go
+++ b/sys/sys_386.go
@@ -489,12 +489,12 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "src_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "offset", TypeSize: 1}}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4}, Val: 1},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Val: 1},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "parent", Protocol: 33},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "seq_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "ack_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
@@ -1527,10 +1527,10 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "seq_num", TypeSize: 2}, BigEndian: true}},
 	}}},
 	{Key: StructKey{Name: "icmp_ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmp_ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "total_len", TypeSize: 2}, BigEndian: true}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -1641,8 +1641,8 @@ var structDescs = []*KeyedStruct{
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "data"}},
 	}}},
 	{Key: StructKey{Name: "icmpv6_ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmpv6_ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "length", TypeSize: 2}, BigEndian: true}},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2108,10 +2108,10 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "a3", TypeSize: 1, ArgDir: 2}}, Val: 187},
 	}}},
 	{Key: StructKey{Name: "ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "total_len", TypeSize: 2}, BigEndian: true}, Buf: "ipv4_packet"},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -2182,8 +2182,8 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "type", TypeSize: 1}}, Val: 68},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 1}}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "pointer", TypeSize: 1}}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4}, Vals: []uint64{0, 1, 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 3}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "timestamps"}, Type: &StructType{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}}},
 	}}},
 	{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_timestamp"}, Fields: []Type{
@@ -2301,9 +2301,9 @@ var structDescs = []*KeyedStruct{
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_hi", TypeSize: 1}}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "identification", TypeSize: 4}}, ValuesStart: 100, ValuesPerProc: 4},
 	}}},
 	{Key: StructKey{Name: "ipv6_hopots_ext_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_hopots_ext_header"}, Fields: []Type{
@@ -2321,8 +2321,8 @@ var structDescs = []*KeyedStruct{
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "ifindex", FldName: "ifindex", TypeSize: 4, ArgDir: 1}},
 	}}},
 	{Key: StructKey{Name: "ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 2}, BigEndian: true}, Buf: "payload"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2928,14 +2928,14 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_vmwrite"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_vmwrite", TypeSize: 16}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "typ", TypeSize: 8}}, Val: 8},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48}},
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_x86"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_x86"}, Fields: []Type{
 		&StructType{Key: StructKey{Name: "kvm_setup_opt_cr0"}, FldName: "cr0"},
@@ -4945,15 +4945,15 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct0"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct0", TypeSize: 32}, Fields: []Type{
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10, BitfieldLst: true}, Vals: []uint64{0, 1, 2}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10}, Vals: []uint64{0, 1, 2}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 6}}, IsPad: true},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5}, Val: 66},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5, BitfieldMdl: true}, Val: 66},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 2}}, IsPad: true},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15, BitfieldLst: true}, Val: 66},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11, BitfieldLst: true}, Buf: "parent"},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true, BitfieldLst: true}, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15}, Val: 66},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11}, Buf: "parent"},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f7", TypeSize: 1}}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 3}}, IsPad: true},
 	}}},
@@ -4962,16 +4962,16 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f1", TypeSize: 1}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct1_internal"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct1_internal", TypeSize: 4}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
 	}}},
 	{Key: StructKey{Name: "syz_csum_encode"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_encode"}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f0", TypeSize: 2}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "f1", TypeSize: 2}, BigEndian: true}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f2"}, Type: &IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", TypeSize: 4}}}, Kind: 1, RangeEnd: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f5", TypeSize: 4}, Kind: 1, RangeBegin: 4, RangeEnd: 4},
 	}}},
 	{Key: StructKey{Name: "syz_csum_icmp_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_icmp_packet"}, Fields: []Type{
@@ -5044,13 +5044,13 @@ var structDescs = []*KeyedStruct{
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "f3", TypeSize: 1}}, ByteSize: 4, Buf: "f0"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bf_struct_inner"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bf_struct_inner", TypeSize: 20}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f7", TypeSize: 4}}, Buf: "parent"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bytesize2_struct"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bytesize2_struct", TypeSize: 12}, Fields: []Type{
@@ -5260,9 +5260,9 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "seq_num", TypeSize: 4}},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "ack_num", TypeSize: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3}},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, ByteSize: 4, Buf: "parent"},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3, BitfieldMdl: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "tcp_flags", FldName: "flags", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 8, 16, 32, 64, 128, 194}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "window_size", TypeSize: 2}, BigEndian: true}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "tcp_packet", Protocol: 6},
@@ -5679,15 +5679,15 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "vlan_tag_ad"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_ad", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 37120},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vlan_tag_q"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_q", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 33024},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vt_consize"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vt_consize", TypeSize: 12}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "rows", TypeSize: 2}}},
diff --git a/sys/sys_amd64.go b/sys/sys_amd64.go
index d29fa0804..56b7d3587 100644
--- a/sys/sys_amd64.go
+++ b/sys/sys_amd64.go
@@ -495,12 +495,12 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "src_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "offset", TypeSize: 1}}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4}, Val: 1},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Val: 1},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "parent", Protocol: 33},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "seq_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "ack_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
@@ -1547,10 +1547,10 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "seq_num", TypeSize: 2}, BigEndian: true}},
 	}}},
 	{Key: StructKey{Name: "icmp_ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmp_ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "total_len", TypeSize: 2}, BigEndian: true}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -1661,8 +1661,8 @@ var structDescs = []*KeyedStruct{
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "data"}},
 	}}},
 	{Key: StructKey{Name: "icmpv6_ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmpv6_ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "length", TypeSize: 2}, BigEndian: true}},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2131,10 +2131,10 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "a3", TypeSize: 1, ArgDir: 2}}, Val: 187},
 	}}},
 	{Key: StructKey{Name: "ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "total_len", TypeSize: 2}, BigEndian: true}, Buf: "ipv4_packet"},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -2205,8 +2205,8 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "type", TypeSize: 1}}, Val: 68},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 1}}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "pointer", TypeSize: 1}}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4}, Vals: []uint64{0, 1, 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 3}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "timestamps"}, Type: &StructType{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}}},
 	}}},
 	{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_timestamp"}, Fields: []Type{
@@ -2324,9 +2324,9 @@ var structDescs = []*KeyedStruct{
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_hi", TypeSize: 1}}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "identification", TypeSize: 4}}, ValuesStart: 100, ValuesPerProc: 4},
 	}}},
 	{Key: StructKey{Name: "ipv6_hopots_ext_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_hopots_ext_header"}, Fields: []Type{
@@ -2344,8 +2344,8 @@ var structDescs = []*KeyedStruct{
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "ifindex", FldName: "ifindex", TypeSize: 4, ArgDir: 1}},
 	}}},
 	{Key: StructKey{Name: "ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 2}, BigEndian: true}, Buf: "payload"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2951,14 +2951,14 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_vmwrite"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_vmwrite", TypeSize: 16}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "typ", TypeSize: 8}}, Val: 8},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48}},
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_x86"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_x86"}, Fields: []Type{
 		&StructType{Key: StructKey{Name: "kvm_setup_opt_cr0"}, FldName: "cr0"},
@@ -4993,15 +4993,15 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct0"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct0", TypeSize: 32}, Fields: []Type{
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10, BitfieldLst: true}, Vals: []uint64{0, 1, 2}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10}, Vals: []uint64{0, 1, 2}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 6}}, IsPad: true},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5}, Val: 66},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5, BitfieldMdl: true}, Val: 66},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 2}}, IsPad: true},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15, BitfieldLst: true}, Val: 66},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11, BitfieldLst: true}, Buf: "parent"},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true, BitfieldLst: true}, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15}, Val: 66},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11}, Buf: "parent"},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f7", TypeSize: 1}}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 3}}, IsPad: true},
 	}}},
@@ -5010,16 +5010,16 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f1", TypeSize: 1}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct1_internal"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct1_internal", TypeSize: 4}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
 	}}},
 	{Key: StructKey{Name: "syz_csum_encode"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_encode"}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f0", TypeSize: 2}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "f1", TypeSize: 2}, BigEndian: true}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f2"}, Type: &IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", TypeSize: 4}}}, Kind: 1, RangeEnd: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f5", TypeSize: 4}, Kind: 1, RangeBegin: 4, RangeEnd: 4},
 	}}},
 	{Key: StructKey{Name: "syz_csum_icmp_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_icmp_packet"}, Fields: []Type{
@@ -5092,13 +5092,13 @@ var structDescs = []*KeyedStruct{
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "f3", TypeSize: 1}}, ByteSize: 4, Buf: "f0"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bf_struct_inner"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bf_struct_inner", TypeSize: 20}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f7", TypeSize: 4}}, Buf: "parent"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bytesize2_struct"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bytesize2_struct", TypeSize: 12}, Fields: []Type{
@@ -5307,9 +5307,9 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "seq_num", TypeSize: 4}},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "ack_num", TypeSize: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3}},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, ByteSize: 4, Buf: "parent"},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3, BitfieldMdl: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "tcp_flags", FldName: "flags", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 8, 16, 32, 64, 128, 194}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "window_size", TypeSize: 2}, BigEndian: true}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "tcp_packet", Protocol: 6},
@@ -5729,15 +5729,15 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "vlan_tag_ad"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_ad", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 37120},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vlan_tag_q"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_q", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 33024},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vt_consize"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vt_consize", TypeSize: 12}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "rows", TypeSize: 2}}},
diff --git a/sys/sys_arm.go b/sys/sys_arm.go
index 7f777d985..0af42926a 100644
--- a/sys/sys_arm.go
+++ b/sys/sys_arm.go
@@ -489,12 +489,12 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "src_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "offset", TypeSize: 1}}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4}, Val: 1},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Val: 1},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "parent", Protocol: 33},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "seq_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "ack_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
@@ -1527,10 +1527,10 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "seq_num", TypeSize: 2}, BigEndian: true}},
 	}}},
 	{Key: StructKey{Name: "icmp_ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmp_ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "total_len", TypeSize: 2}, BigEndian: true}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -1641,8 +1641,8 @@ var structDescs = []*KeyedStruct{
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "data"}},
 	}}},
 	{Key: StructKey{Name: "icmpv6_ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmpv6_ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "length", TypeSize: 2}, BigEndian: true}},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2108,10 +2108,10 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "a3", TypeSize: 1, ArgDir: 2}}, Val: 187},
 	}}},
 	{Key: StructKey{Name: "ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "total_len", TypeSize: 2}, BigEndian: true}, Buf: "ipv4_packet"},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -2182,8 +2182,8 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "type", TypeSize: 1}}, Val: 68},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 1}}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "pointer", TypeSize: 1}}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4}, Vals: []uint64{0, 1, 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 3}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "timestamps"}, Type: &StructType{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}}},
 	}}},
 	{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_timestamp"}, Fields: []Type{
@@ -2301,9 +2301,9 @@ var structDescs = []*KeyedStruct{
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_hi", TypeSize: 1}}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "identification", TypeSize: 4}}, ValuesStart: 100, ValuesPerProc: 4},
 	}}},
 	{Key: StructKey{Name: "ipv6_hopots_ext_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_hopots_ext_header"}, Fields: []Type{
@@ -2321,8 +2321,8 @@ var structDescs = []*KeyedStruct{
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "ifindex", FldName: "ifindex", TypeSize: 4, ArgDir: 1}},
 	}}},
 	{Key: StructKey{Name: "ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 2}, BigEndian: true}, Buf: "payload"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2928,14 +2928,14 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_vmwrite"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_vmwrite", TypeSize: 16}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "typ", TypeSize: 8}}, Val: 8},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48}},
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_x86"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_x86"}, Fields: []Type{
 		&StructType{Key: StructKey{Name: "kvm_setup_opt_cr0"}, FldName: "cr0"},
@@ -4945,15 +4945,15 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct0"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct0", TypeSize: 32}, Fields: []Type{
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10, BitfieldLst: true}, Vals: []uint64{0, 1, 2}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10}, Vals: []uint64{0, 1, 2}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 6}}, IsPad: true},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5}, Val: 66},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5, BitfieldMdl: true}, Val: 66},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 2}}, IsPad: true},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15, BitfieldLst: true}, Val: 66},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11, BitfieldLst: true}, Buf: "parent"},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true, BitfieldLst: true}, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15}, Val: 66},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11}, Buf: "parent"},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f7", TypeSize: 1}}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 3}}, IsPad: true},
 	}}},
@@ -4962,16 +4962,16 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f1", TypeSize: 1}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct1_internal"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct1_internal", TypeSize: 4}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
 	}}},
 	{Key: StructKey{Name: "syz_csum_encode"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_encode"}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f0", TypeSize: 2}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "f1", TypeSize: 2}, BigEndian: true}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f2"}, Type: &IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", TypeSize: 4}}}, Kind: 1, RangeEnd: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f5", TypeSize: 4}, Kind: 1, RangeBegin: 4, RangeEnd: 4},
 	}}},
 	{Key: StructKey{Name: "syz_csum_icmp_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_icmp_packet"}, Fields: []Type{
@@ -5044,13 +5044,13 @@ var structDescs = []*KeyedStruct{
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "f3", TypeSize: 1}}, ByteSize: 4, Buf: "f0"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bf_struct_inner"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bf_struct_inner", TypeSize: 20}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f7", TypeSize: 4}}, Buf: "parent"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bytesize2_struct"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bytesize2_struct", TypeSize: 12}, Fields: []Type{
@@ -5260,9 +5260,9 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "seq_num", TypeSize: 4}},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "ack_num", TypeSize: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3}},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, ByteSize: 4, Buf: "parent"},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3, BitfieldMdl: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "tcp_flags", FldName: "flags", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 8, 16, 32, 64, 128, 194}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "window_size", TypeSize: 2}, BigEndian: true}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "tcp_packet", Protocol: 6},
@@ -5679,15 +5679,15 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "vlan_tag_ad"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_ad", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 37120},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vlan_tag_q"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_q", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 33024},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vt_consize"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vt_consize", TypeSize: 12}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "rows", TypeSize: 2}}},
diff --git a/sys/sys_arm64.go b/sys/sys_arm64.go
index 8ad2b1f1b..caa717d9f 100644
--- a/sys/sys_arm64.go
+++ b/sys/sys_arm64.go
@@ -495,12 +495,12 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "src_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "offset", TypeSize: 1}}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4}, Val: 1},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Val: 1},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "parent", Protocol: 33},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "seq_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "ack_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
@@ -1547,10 +1547,10 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "seq_num", TypeSize: 2}, BigEndian: true}},
 	}}},
 	{Key: StructKey{Name: "icmp_ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmp_ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "total_len", TypeSize: 2}, BigEndian: true}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -1661,8 +1661,8 @@ var structDescs = []*KeyedStruct{
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "data"}},
 	}}},
 	{Key: StructKey{Name: "icmpv6_ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmpv6_ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "length", TypeSize: 2}, BigEndian: true}},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2131,10 +2131,10 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "a3", TypeSize: 1, ArgDir: 2}}, Val: 187},
 	}}},
 	{Key: StructKey{Name: "ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "total_len", TypeSize: 2}, BigEndian: true}, Buf: "ipv4_packet"},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -2205,8 +2205,8 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "type", TypeSize: 1}}, Val: 68},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 1}}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "pointer", TypeSize: 1}}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4}, Vals: []uint64{0, 1, 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 3}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "timestamps"}, Type: &StructType{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}}},
 	}}},
 	{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_timestamp"}, Fields: []Type{
@@ -2324,9 +2324,9 @@ var structDescs = []*KeyedStruct{
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_hi", TypeSize: 1}}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "identification", TypeSize: 4}}, ValuesStart: 100, ValuesPerProc: 4},
 	}}},
 	{Key: StructKey{Name: "ipv6_hopots_ext_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_hopots_ext_header"}, Fields: []Type{
@@ -2344,8 +2344,8 @@ var structDescs = []*KeyedStruct{
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "ifindex", FldName: "ifindex", TypeSize: 4, ArgDir: 1}},
 	}}},
 	{Key: StructKey{Name: "ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 2}, BigEndian: true}, Buf: "payload"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2951,14 +2951,14 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_vmwrite"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_vmwrite", TypeSize: 16}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "typ", TypeSize: 8}}, Val: 8},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48}},
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_x86"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_x86"}, Fields: []Type{
 		&StructType{Key: StructKey{Name: "kvm_setup_opt_cr0"}, FldName: "cr0"},
@@ -4993,15 +4993,15 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct0"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct0", TypeSize: 32}, Fields: []Type{
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10, BitfieldLst: true}, Vals: []uint64{0, 1, 2}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10}, Vals: []uint64{0, 1, 2}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 6}}, IsPad: true},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5}, Val: 66},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5, BitfieldMdl: true}, Val: 66},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 2}}, IsPad: true},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15, BitfieldLst: true}, Val: 66},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11, BitfieldLst: true}, Buf: "parent"},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true, BitfieldLst: true}, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15}, Val: 66},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11}, Buf: "parent"},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f7", TypeSize: 1}}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 3}}, IsPad: true},
 	}}},
@@ -5010,16 +5010,16 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f1", TypeSize: 1}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct1_internal"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct1_internal", TypeSize: 4}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
 	}}},
 	{Key: StructKey{Name: "syz_csum_encode"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_encode"}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f0", TypeSize: 2}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "f1", TypeSize: 2}, BigEndian: true}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f2"}, Type: &IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", TypeSize: 4}}}, Kind: 1, RangeEnd: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f5", TypeSize: 4}, Kind: 1, RangeBegin: 4, RangeEnd: 4},
 	}}},
 	{Key: StructKey{Name: "syz_csum_icmp_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_icmp_packet"}, Fields: []Type{
@@ -5092,13 +5092,13 @@ var structDescs = []*KeyedStruct{
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "f3", TypeSize: 1}}, ByteSize: 4, Buf: "f0"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bf_struct_inner"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bf_struct_inner", TypeSize: 20}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f7", TypeSize: 4}}, Buf: "parent"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bytesize2_struct"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bytesize2_struct", TypeSize: 12}, Fields: []Type{
@@ -5307,9 +5307,9 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "seq_num", TypeSize: 4}},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "ack_num", TypeSize: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3}},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, ByteSize: 4, Buf: "parent"},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3, BitfieldMdl: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "tcp_flags", FldName: "flags", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 8, 16, 32, 64, 128, 194}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "window_size", TypeSize: 2}, BigEndian: true}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "tcp_packet", Protocol: 6},
@@ -5729,15 +5729,15 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "vlan_tag_ad"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_ad", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 37120},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vlan_tag_q"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_q", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 33024},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vt_consize"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vt_consize", TypeSize: 12}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "rows", TypeSize: 2}}},
diff --git a/sys/sys_ppc64le.go b/sys/sys_ppc64le.go
index c86a42ed8..28c99f185 100644
--- a/sys/sys_ppc64le.go
+++ b/sys/sys_ppc64le.go
@@ -495,12 +495,12 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "src_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "offset", TypeSize: 1}}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4}, Val: 1},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "cscov", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Val: 1},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ccval", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "parent", Protocol: 33},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "x", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "dccp_types", FldName: "type", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}, BitfieldOff: 5, BitfieldLen: 3}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "seq_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "ack_num", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
@@ -1547,10 +1547,10 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "seq_num", TypeSize: 2}, BigEndian: true}},
 	}}},
 	{Key: StructKey{Name: "icmp_ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmp_ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "total_len", TypeSize: 2}, BigEndian: true}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -1661,8 +1661,8 @@ var structDescs = []*KeyedStruct{
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "data"}},
 	}}},
 	{Key: StructKey{Name: "icmpv6_ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "icmpv6_ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "length", TypeSize: 2}, BigEndian: true}},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2131,10 +2131,10 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "a3", TypeSize: 1, ArgDir: 2}}, Val: 187},
 	}}},
 	{Key: StructKey{Name: "ipv4_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_header"}, Fields: []Type{
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6, BitfieldLst: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "ihl", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, ByteSize: 4, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 4},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ecn", TypeSize: 1}, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "dscp", TypeSize: 1}, BitfieldOff: 2, BitfieldLen: 6}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "total_len", TypeSize: 2}, BigEndian: true}, Buf: "ipv4_packet"},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "id", TypeSize: 2}, BigEndian: true}, ValuesStart: 100, ValuesPerProc: 4},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "frag_off", TypeSize: 2}, BigEndian: true}},
@@ -2205,8 +2205,8 @@ var structDescs = []*KeyedStruct{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "type", TypeSize: 1}}, Val: 68},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 1}}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "pointer", TypeSize: 1}}},
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4}, Vals: []uint64{0, 1, 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_flags", FldName: "flg", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}, Vals: []uint64{0, 1, 3}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "oflw", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "timestamps"}, Type: &StructType{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}}},
 	}}},
 	{Key: StructKey{Name: "ipv4_option_timestamp_timestamp"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv4_option_timestamp_timestamp"}, Fields: []Type{
@@ -2324,9 +2324,9 @@ var structDescs = []*KeyedStruct{
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved1", TypeSize: 1}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_hi", TypeSize: 1}}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "m_flag", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "reserved2", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 2, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "fragment_off_lo", TypeSize: 1}, BitfieldOff: 3, BitfieldLen: 5}},
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "identification", TypeSize: 4}}, ValuesStart: 100, ValuesPerProc: 4},
 	}}},
 	{Key: StructKey{Name: "ipv6_hopots_ext_header"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_hopots_ext_header"}, Fields: []Type{
@@ -2344,8 +2344,8 @@ var structDescs = []*KeyedStruct{
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "ifindex", FldName: "ifindex", TypeSize: 4, ArgDir: 1}},
 	}}},
 	{Key: StructKey{Name: "ipv6_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "ipv6_packet"}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, Val: 6},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "priority", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "version", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, Val: 6},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "flow_label", TypeSize: 3}, Kind: 1, RangeBegin: 3, RangeEnd: 3},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "length", TypeSize: 2}, BigEndian: true}, Buf: "payload"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "ipv6_types", FldName: "next_header", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 6, 8, 12, 17, 22, 29, 33, 41, 46, 47, 50, 51, 92, 94, 98, 103, 108, 132, 136, 137, 255, 0, 43, 44, 58, 59, 60, 135, 0, 43, 44, 47, 50, 51, 58, 59, 60, 135}},
@@ -2951,14 +2951,14 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_vmwrite"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_vmwrite", TypeSize: 16}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "typ", TypeSize: 8}}, Val: 8},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "sz", TypeSize: 8}, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fld", TypeSize: 8}, BitfieldOff: 1, BitfieldLen: 5, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad0", TypeSize: 8}, BitfieldOff: 6, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "ftyp", TypeSize: 8}, BitfieldOff: 10, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad1", TypeSize: 8}, BitfieldOff: 12, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "fsz", TypeSize: 8}, BitfieldOff: 13, BitfieldLen: 2, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "pad2", TypeSize: 8}, BitfieldOff: 15, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "val", TypeSize: 8}, BitfieldOff: 16, BitfieldLen: 48}},
 	}}},
 	{Key: StructKey{Name: "kvm_setup_opt_x86"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "kvm_setup_opt_x86"}, Fields: []Type{
 		&StructType{Key: StructKey{Name: "kvm_setup_opt_cr0"}, FldName: "cr0"},
@@ -4993,15 +4993,15 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct0"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct0", TypeSize: 32}, Fields: []Type{
-		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10, BitfieldLst: true}, Vals: []uint64{0, 1, 2}},
+		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "syz_bf_flags", FldName: "f0", TypeSize: 2}, BitfieldLen: 10}, Vals: []uint64{0, 1, 2}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 6}}, IsPad: true},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int64", FldName: "f1", TypeSize: 8}}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5}, Val: 66},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6, BitfieldLst: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f2", TypeSize: 2}, BitfieldLen: 5, BitfieldMdl: true}, Val: 66},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f3", TypeSize: 2}, BitfieldOff: 5, BitfieldLen: 6}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 2}}, IsPad: true},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15, BitfieldLst: true}, Val: 66},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11, BitfieldLst: true}, Buf: "parent"},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true, BitfieldLst: true}, Buf: "parent"},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "f4", TypeSize: 4}, BitfieldLen: 15}, Val: 66},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f5", TypeSize: 2}, BitfieldLen: 11}, Buf: "parent"},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f6", TypeSize: 2}, BitfieldLen: 11, BigEndian: true}, Buf: "parent"},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f7", TypeSize: 1}}},
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "pad", TypeSize: 3}}, IsPad: true},
 	}}},
@@ -5010,16 +5010,16 @@ var structDescs = []*KeyedStruct{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f1", TypeSize: 1}}},
 	}}},
 	{Key: StructKey{Name: "syz_bf_struct1_internal"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_bf_struct1_internal", TypeSize: 4}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
 	}}},
 	{Key: StructKey{Name: "syz_csum_encode"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_encode"}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "f0", TypeSize: 2}}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "f1", TypeSize: 2}, BigEndian: true}},
 		&ArrayType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f2"}, Type: &IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", TypeSize: 4}}}, Kind: 1, RangeEnd: 4},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f3", TypeSize: 1}, BitfieldLen: 4, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "f4", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}},
 		&BufferType{TypeCommon: TypeCommon{TypeName: "array", FldName: "f5", TypeSize: 4}, Kind: 1, RangeBegin: 4, RangeEnd: 4},
 	}}},
 	{Key: StructKey{Name: "syz_csum_icmp_packet"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_csum_icmp_packet"}, Fields: []Type{
@@ -5092,13 +5092,13 @@ var structDescs = []*KeyedStruct{
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "f3", TypeSize: 1}}, ByteSize: 4, Buf: "f0"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bf_struct_inner"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bf_struct_inner", TypeSize: 20}, Fields: []Type{
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16, BitfieldLst: true}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f0", TypeSize: 4}, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f1", TypeSize: 4}, BitfieldOff: 10, BitfieldLen: 10, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f2", TypeSize: 4}, BitfieldOff: 20, BitfieldLen: 10}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f3", TypeSize: 4}, BitfieldLen: 32}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f4", TypeSize: 4}, BitfieldLen: 16, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f5", TypeSize: 4}, BitfieldOff: 16, BitfieldLen: 16}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int32", FldName: "f6", TypeSize: 4}, BitfieldLen: 10}},
 		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "len", FldName: "f7", TypeSize: 4}}, Buf: "parent"},
 	}}},
 	{Key: StructKey{Name: "syz_length_bytesize2_struct"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "syz_length_bytesize2_struct", TypeSize: 12}, Fields: []Type{
@@ -5307,9 +5307,9 @@ var structDescs = []*KeyedStruct{
 		&ProcType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "proc", FldName: "dst_port", TypeSize: 2}, BigEndian: true}, ValuesStart: 20000, ValuesPerProc: 4},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "seq_num", TypeSize: 4}},
 		&ResourceType{TypeCommon: TypeCommon{TypeName: "tcp_seq_num", FldName: "ack_num", TypeSize: 4}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1}},
-		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3}},
-		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4, BitfieldLst: true}, ByteSize: 4, Buf: "parent"},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int8", FldName: "ns", TypeSize: 1}, BitfieldLen: 1, BitfieldMdl: true}},
+		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "reserved", TypeSize: 1}, BitfieldOff: 1, BitfieldLen: 3, BitfieldMdl: true}},
+		&LenType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "bytesize4", FldName: "data_off", TypeSize: 1}, BitfieldOff: 4, BitfieldLen: 4}, ByteSize: 4, Buf: "parent"},
 		&FlagsType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "tcp_flags", FldName: "flags", TypeSize: 1}}, Vals: []uint64{0, 1, 2, 4, 8, 16, 32, 64, 128, 194}},
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16be", FldName: "window_size", TypeSize: 2}, BigEndian: true}},
 		&CsumType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "csum", FldName: "csum", TypeSize: 2}, BigEndian: true}, Kind: 1, Buf: "tcp_packet", Protocol: 6},
@@ -5729,15 +5729,15 @@ var structDescs = []*KeyedStruct{
 	}}},
 	{Key: StructKey{Name: "vlan_tag_ad"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_ad", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 37120},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vlan_tag_q"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vlan_tag_q", TypeSize: 4}, Fields: []Type{
 		&ConstType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "const", FldName: "tpid", TypeSize: 2}, BigEndian: true}, Val: 33024},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1}},
-		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12, BitfieldLst: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "pcp", TypeSize: 2}, BitfieldLen: 3, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "dei", TypeSize: 2}, BitfieldOff: 3, BitfieldLen: 1, BitfieldMdl: true}},
+		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "vid", TypeSize: 2}, BitfieldOff: 4, BitfieldLen: 12}},
 	}}},
 	{Key: StructKey{Name: "vt_consize"}, Desc: &StructDesc{TypeCommon: TypeCommon{TypeName: "vt_consize", TypeSize: 12}, Fields: []Type{
 		&IntType{IntTypeCommon: IntTypeCommon{TypeCommon: TypeCommon{TypeName: "int16", FldName: "rows", TypeSize: 2}}},