package reflectdata
import (
+ "encoding/binary"
"fmt"
"internal/buildcfg"
"os"
// dnameData writes the contents of a reflect.name into s at offset ot.
func dnameData(s *obj.LSym, ot int, name, tag string, pkg *types.Pkg, exported bool) int {
- if len(name) > 1<<16-1 {
- base.Fatalf("name too long: %s", name)
+ if len(name) >= 1<<29 {
+ base.Fatalf("name too long: %d %s...", len(name), name[:1024])
}
- if len(tag) > 1<<16-1 {
- base.Fatalf("tag too long: %s", tag)
+ if len(tag) >= 1<<29 {
+ base.Fatalf("tag too long: %d %s...", len(tag), tag[:1024])
}
+ var nameLen [binary.MaxVarintLen64]byte
+ nameLenLen := binary.PutUvarint(nameLen[:], uint64(len(name)))
+ var tagLen [binary.MaxVarintLen64]byte
+ tagLenLen := binary.PutUvarint(tagLen[:], uint64(len(tag)))
// Encode name and tag. See reflect/type.go for details.
var bits byte
- l := 1 + 2 + len(name)
+ l := 1 + nameLenLen + len(name)
if exported {
bits |= 1 << 0
}
if len(tag) > 0 {
- l += 2 + len(tag)
+ l += tagLenLen + len(tag)
bits |= 1 << 1
}
if pkg != nil {
}
b := make([]byte, l)
b[0] = bits
- b[1] = uint8(len(name) >> 8)
- b[2] = uint8(len(name))
- copy(b[3:], name)
+ copy(b[1:], nameLen[:nameLenLen])
+ copy(b[1+nameLenLen:], name)
if len(tag) > 0 {
- tb := b[3+len(name):]
- tb[0] = uint8(len(tag) >> 8)
- tb[1] = uint8(len(tag))
- copy(tb[2:], tag)
+ tb := b[1+nameLenLen+len(name):]
+ copy(tb, tagLen[:tagLenLen])
+ copy(tb[tagLenLen:], tag)
}
ot = int(s.WriteBytes(base.Ctxt, int64(ot), b))
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"debug/elf"
+ "encoding/binary"
"log"
)
}
data := ldr.Data(r)
- namelen := int(uint16(data[1])<<8 | uint16(data[2]))
- return string(data[3 : 3+namelen])
+ nameLen, nameLenLen := binary.Uvarint(data[1:])
+ return string(data[1+nameLenLen : 1+nameLenLen+int(nameLen)])
}
func decodetypeFuncInType(ldr *loader.Loader, arch *sys.Arch, symIdx loader.Sym, relocs *loader.Relocs, i int) loader.Sym {
}
}
-type embed struct {
- EmbedWithUnexpMeth
-}
-
-func TestNameBytesAreAligned(t *testing.T) {
- typ := TypeOf(embed{})
- b := FirstMethodNameBytes(typ)
- v := uintptr(unsafe.Pointer(b))
- if v%unsafe.Alignof((*byte)(nil)) != 0 {
- t.Errorf("reflect.name.bytes pointer is not aligned: %x", v)
- }
-}
-
// TestUnaddressableField tests that the reflect package will not allow
// a type from another package to be used as a named type with an
// unexported field.
return (*n.bytes)&(1<<0) != 0
}
-func (n name) nameLen() int {
- return int(uint16(*n.data(1, "name len field"))<<8 | uint16(*n.data(2, "name len field")))
-}
-
-func (n name) tagLen() int {
- if *n.data(0, "name flag field")&(1<<1) == 0 {
- return 0
+func (n name) hasTag() bool {
+ return (*n.bytes)&(1<<1) != 0
+}
+
+// readVarint parses a varint as encoded by encoding/binary.
+// It returns the number of encoded bytes and the encoded value.
+func (n name) readVarint(off int) (int, int) {
+ v := 0
+ for i := 0; ; i++ {
+ x := *n.data(off+i, "read varint")
+ v += int(x&0x7f) << (7 * i)
+ if x&0x80 == 0 {
+ return i + 1, v
+ }
}
- off := 3 + n.nameLen()
- return int(uint16(*n.data(off, "name taglen field"))<<8 | uint16(*n.data(off+1, "name taglen field")))
}
func (n name) name() (s string) {
if n.bytes == nil {
return
}
- b := (*[4]byte)(unsafe.Pointer(n.bytes))
-
+ i, l := n.readVarint(1)
hdr := (*unsafeheader.String)(unsafe.Pointer(&s))
- hdr.Data = unsafe.Pointer(&b[3])
- hdr.Len = int(b[1])<<8 | int(b[2])
- return s
+ hdr.Data = unsafe.Pointer(n.data(1+i, "non-empty string"))
+ hdr.Len = l
+ return
}
func (n name) tag() (s string) {
- tl := n.tagLen()
- if tl == 0 {
+ if !n.hasTag() {
return ""
}
- nl := n.nameLen()
+ i, l := n.readVarint(1)
+ i2, l2 := n.readVarint(1 + i + l)
hdr := (*unsafeheader.String)(unsafe.Pointer(&s))
- hdr.Data = unsafe.Pointer(n.data(3+nl+2, "non-empty string"))
- hdr.Len = tl
- return s
+ hdr.Data = unsafe.Pointer(n.data(1+i+l+i2, "non-empty string"))
+ hdr.Len = l2
+ return
}
func (n name) pkgPath() string {
if n.bytes == nil || *n.data(0, "name flag field")&(1<<2) == 0 {
return ""
}
- off := 3 + n.nameLen()
- if tl := n.tagLen(); tl > 0 {
- off += 2 + tl
+ i, l := n.readVarint(1)
+ off := 1 + i + l
+ if n.hasTag() {
+ i2, l2 := n.readVarint(off)
+ off += i2 + l2
}
var nameOff int32
// Note that this field may not be aligned in memory,
}
}
-type embed struct {
- EmbedWithUnexpMeth
-}
-
-func TestNameBytesAreAligned(t *testing.T) {
- typ := TypeOf(embed{})
- b := FirstMethodNameBytes(typ)
- v := uintptr(unsafe.Pointer(b))
- if v%unsafe.Alignof((*byte)(nil)) != 0 {
- t.Errorf("reflect.name.bytes pointer is not aligned: %x", v)
- }
-}
-
func TestTypeStrings(t *testing.T) {
type stringTest struct {
typ Type
// 1<<1 tag data follows the name
// 1<<2 pkgPath nameOff follows the name and tag
//
-// The next two bytes are the data length:
+// Following that, there is a varint-encoded length of the name,
+// followed by the name itself.
//
-// l := uint16(data[1])<<8 | uint16(data[2])
-//
-// Bytes [3:3+l] are the string data.
-//
-// If tag data follows then bytes 3+l and 3+l+1 are the tag length,
-// with the data following.
+// If tag data is present, it also has a varint-encoded length
+// followed by the tag itself.
//
// If the import path follows, then 4 bytes at the end of
// the data form a nameOff. The import path is only set for concrete
//
// If a name starts with "*", then the exported bit represents
// whether the pointed to type is exported.
+//
+// Note: this encoding must match here and in:
+// cmd/compile/internal/reflectdata/reflect.go
+// runtime/type.go
+// internal/reflectlite/type.go
+// cmd/link/internal/ld/decodesym.go
+
type name struct {
bytes *byte
}
return (*n.bytes)&(1<<0) != 0
}
-func (n name) nameLen() int {
- return int(uint16(*n.data(1, "name len field"))<<8 | uint16(*n.data(2, "name len field")))
+func (n name) hasTag() bool {
+ return (*n.bytes)&(1<<1) != 0
+}
+
+// readVarint parses a varint as encoded by encoding/binary.
+// It returns the number of encoded bytes and the encoded value.
+func (n name) readVarint(off int) (int, int) {
+ v := 0
+ for i := 0; ; i++ {
+ x := *n.data(off+i, "read varint")
+ v += int(x&0x7f) << (7 * i)
+ if x&0x80 == 0 {
+ return i + 1, v
+ }
+ }
}
-func (n name) tagLen() int {
- if *n.data(0, "name flag field")&(1<<1) == 0 {
- return 0
+// writeVarint writes n to buf in varint form. Returns the
+// number of bytes written. n must be nonnegative.
+// Writes at most 10 bytes.
+func writeVarint(buf []byte, n int) int {
+ for i := 0; ; i++ {
+ b := byte(n & 0x7f)
+ n >>= 7
+ if n == 0 {
+ buf[i] = b
+ return i + 1
+ }
+ buf[i] = b | 0x80
}
- off := 3 + n.nameLen()
- return int(uint16(*n.data(off, "name taglen field"))<<8 | uint16(*n.data(off+1, "name taglen field")))
}
func (n name) name() (s string) {
if n.bytes == nil {
return
}
- b := (*[4]byte)(unsafe.Pointer(n.bytes))
-
+ i, l := n.readVarint(1)
hdr := (*unsafeheader.String)(unsafe.Pointer(&s))
- hdr.Data = unsafe.Pointer(&b[3])
- hdr.Len = int(b[1])<<8 | int(b[2])
- return s
+ hdr.Data = unsafe.Pointer(n.data(1+i, "non-empty string"))
+ hdr.Len = l
+ return
}
func (n name) tag() (s string) {
- tl := n.tagLen()
- if tl == 0 {
+ if !n.hasTag() {
return ""
}
- nl := n.nameLen()
+ i, l := n.readVarint(1)
+ i2, l2 := n.readVarint(1 + i + l)
hdr := (*unsafeheader.String)(unsafe.Pointer(&s))
- hdr.Data = unsafe.Pointer(n.data(3+nl+2, "non-empty string"))
- hdr.Len = tl
- return s
+ hdr.Data = unsafe.Pointer(n.data(1+i+l+i2, "non-empty string"))
+ hdr.Len = l2
+ return
}
func (n name) pkgPath() string {
if n.bytes == nil || *n.data(0, "name flag field")&(1<<2) == 0 {
return ""
}
- off := 3 + n.nameLen()
- if tl := n.tagLen(); tl > 0 {
- off += 2 + tl
+ i, l := n.readVarint(1)
+ off := 1 + i + l
+ if n.hasTag() {
+ i2, l2 := n.readVarint(off)
+ off += i2 + l2
}
var nameOff int32
// Note that this field may not be aligned in memory,
}
func newName(n, tag string, exported bool) name {
- if len(n) > 1<<16-1 {
- panic("reflect.nameFrom: name too long: " + n)
+ if len(n) >= 1<<29 {
+ panic("reflect.nameFrom: name too long: " + n[:1024] + "...")
}
- if len(tag) > 1<<16-1 {
- panic("reflect.nameFrom: tag too long: " + tag)
+ if len(tag) >= 1<<29 {
+ panic("reflect.nameFrom: tag too long: " + tag[:1024] + "...")
}
+ var nameLen [10]byte
+ var tagLen [10]byte
+ nameLenLen := writeVarint(nameLen[:], len(n))
+ tagLenLen := writeVarint(tagLen[:], len(tag))
var bits byte
- l := 1 + 2 + len(n)
+ l := 1 + nameLenLen + len(n)
if exported {
bits |= 1 << 0
}
if len(tag) > 0 {
- l += 2 + len(tag)
+ l += tagLenLen + len(tag)
bits |= 1 << 1
}
b := make([]byte, l)
b[0] = bits
- b[1] = uint8(len(n) >> 8)
- b[2] = uint8(len(n))
- copy(b[3:], n)
+ copy(b[1:], nameLen[:nameLenLen])
+ copy(b[1+nameLenLen:], n)
if len(tag) > 0 {
- tb := b[3+len(n):]
- tb[0] = uint8(len(tag) >> 8)
- tb[1] = uint8(len(tag))
- copy(tb[2:], tag)
+ tb := b[1+nameLenLen+len(n):]
+ copy(tb, tagLen[:tagLenLen])
+ copy(tb[tagLenLen:], tag)
}
return name{bytes: &b[0]}
hash = fnv1(hash, byte(ft.hash>>24), byte(ft.hash>>16), byte(ft.hash>>8), byte(ft.hash))
repr = append(repr, (" " + ft.String())...)
- if f.name.tagLen() > 0 {
+ if f.name.hasTag() {
hash = fnv1(hash, []byte(f.name.tag())...)
repr = append(repr, (" " + strconv.Quote(f.name.tag()))...)
}
return (*n.bytes)&(1<<0) != 0
}
-func (n name) nameLen() int {
- return int(uint16(*n.data(1))<<8 | uint16(*n.data(2)))
-}
-
-func (n name) tagLen() int {
- if *n.data(0)&(1<<1) == 0 {
- return 0
+func (n name) readvarint(off int) (int, int) {
+ v := 0
+ for i := 0; ; i++ {
+ x := *n.data(off + i)
+ v += int(x&0x7f) << (7 * i)
+ if x&0x80 == 0 {
+ return i + 1, v
+ }
}
- off := 3 + n.nameLen()
- return int(uint16(*n.data(off))<<8 | uint16(*n.data(off + 1)))
}
func (n name) name() (s string) {
if n.bytes == nil {
return ""
}
- nl := n.nameLen()
- if nl == 0 {
+ i, l := n.readvarint(1)
+ if l == 0 {
return ""
}
hdr := (*stringStruct)(unsafe.Pointer(&s))
- hdr.str = unsafe.Pointer(n.data(3))
- hdr.len = nl
- return s
+ hdr.str = unsafe.Pointer(n.data(1 + i))
+ hdr.len = l
+ return
}
func (n name) tag() (s string) {
- tl := n.tagLen()
- if tl == 0 {
+ if *n.data(0)&(1<<1) == 0 {
return ""
}
- nl := n.nameLen()
+ i, l := n.readvarint(1)
+ i2, l2 := n.readvarint(1 + i + l)
hdr := (*stringStruct)(unsafe.Pointer(&s))
- hdr.str = unsafe.Pointer(n.data(3 + nl + 2))
- hdr.len = tl
- return s
+ hdr.str = unsafe.Pointer(n.data(1 + i + l + i2))
+ hdr.len = l2
+ return
}
func (n name) pkgPath() string {
if n.bytes == nil || *n.data(0)&(1<<2) == 0 {
return ""
}
- off := 3 + n.nameLen()
- if tl := n.tagLen(); tl > 0 {
- off += 2 + tl
+ i, l := n.readvarint(1)
+ off := 1 + i + l
+ if *n.data(0)&(1<<1) != 0 {
+ i2, l2 := n.readvarint(off)
+ off += i2 + l2
}
var nameOff nameOff
copy((*[4]byte)(unsafe.Pointer(&nameOff))[:], (*[4]byte)(unsafe.Pointer(n.data(off)))[:])
if n.bytes == nil {
return false
}
- if n.nameLen() != 1 {
- return false
- }
- return *n.data(3) == '_'
+ _, l := n.readvarint(1)
+ return l == 1 && *n.data(2) == '_'
}
// typelinksinit scans the types from extra modules and builds the