| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package reflectdata |
| |
| import ( |
| "encoding/binary" |
| "fmt" |
| "internal/buildcfg" |
| "os" |
| "sort" |
| "strings" |
| "sync" |
| |
| "cmd/compile/internal/base" |
| "cmd/compile/internal/bitvec" |
| "cmd/compile/internal/escape" |
| "cmd/compile/internal/inline" |
| "cmd/compile/internal/ir" |
| "cmd/compile/internal/objw" |
| "cmd/compile/internal/typebits" |
| "cmd/compile/internal/typecheck" |
| "cmd/compile/internal/types" |
| "cmd/internal/gcprog" |
| "cmd/internal/obj" |
| "cmd/internal/objabi" |
| "cmd/internal/src" |
| ) |
| |
| type itabEntry struct { |
| t, itype *types.Type |
| lsym *obj.LSym // symbol of the itab itself |
| |
| // symbols of each method in |
| // the itab, sorted by byte offset; |
| // filled in by CompileITabs |
| entries []*obj.LSym |
| } |
| |
| type ptabEntry struct { |
| s *types.Sym |
| t *types.Type |
| } |
| |
| func CountTabs() (numPTabs, numITabs int) { |
| return len(ptabs), len(itabs) |
| } |
| |
| // runtime interface and reflection data structures |
| var ( |
| signatmu sync.Mutex // protects signatset and signatslice |
| signatset = make(map[*types.Type]struct{}) |
| signatslice []*types.Type |
| |
| gcsymmu sync.Mutex // protects gcsymset and gcsymslice |
| gcsymset = make(map[*types.Type]struct{}) |
| |
| itabs []itabEntry |
| ptabs []*ir.Name |
| ) |
| |
| type typeSig struct { |
| name *types.Sym |
| isym *obj.LSym |
| tsym *obj.LSym |
| type_ *types.Type |
| mtype *types.Type |
| } |
| |
| // Builds a type representing a Bucket structure for |
| // the given map type. This type is not visible to users - |
| // we include only enough information to generate a correct GC |
| // program for it. |
| // Make sure this stays in sync with runtime/map.go. |
| const ( |
| BUCKETSIZE = 8 |
| MAXKEYSIZE = 128 |
| MAXELEMSIZE = 128 |
| ) |
| |
| func structfieldSize() int { return 3 * types.PtrSize } // Sizeof(runtime.structfield{}) |
| func imethodSize() int { return 4 + 4 } // Sizeof(runtime.imethod{}) |
| func commonSize() int { return 4*types.PtrSize + 8 + 8 } // Sizeof(runtime._type{}) |
| |
| func uncommonSize(t *types.Type) int { // Sizeof(runtime.uncommontype{}) |
| if t.Sym() == nil && len(methods(t)) == 0 { |
| return 0 |
| } |
| return 4 + 2 + 2 + 4 + 4 |
| } |
| |
| func makefield(name string, t *types.Type) *types.Field { |
| sym := (*types.Pkg)(nil).Lookup(name) |
| return types.NewField(src.NoXPos, sym, t) |
| } |
| |
| // MapBucketType makes the map bucket type given the type of the map. |
| func MapBucketType(t *types.Type) *types.Type { |
| if t.MapType().Bucket != nil { |
| return t.MapType().Bucket |
| } |
| |
| keytype := t.Key() |
| elemtype := t.Elem() |
| types.CalcSize(keytype) |
| types.CalcSize(elemtype) |
| if keytype.Width > MAXKEYSIZE { |
| keytype = types.NewPtr(keytype) |
| } |
| if elemtype.Width > MAXELEMSIZE { |
| elemtype = types.NewPtr(elemtype) |
| } |
| |
| field := make([]*types.Field, 0, 5) |
| |
| // The first field is: uint8 topbits[BUCKETSIZE]. |
| arr := types.NewArray(types.Types[types.TUINT8], BUCKETSIZE) |
| field = append(field, makefield("topbits", arr)) |
| |
| arr = types.NewArray(keytype, BUCKETSIZE) |
| arr.SetNoalg(true) |
| keys := makefield("keys", arr) |
| field = append(field, keys) |
| |
| arr = types.NewArray(elemtype, BUCKETSIZE) |
| arr.SetNoalg(true) |
| elems := makefield("elems", arr) |
| field = append(field, elems) |
| |
| // If keys and elems have no pointers, the map implementation |
| // can keep a list of overflow pointers on the side so that |
| // buckets can be marked as having no pointers. |
| // Arrange for the bucket to have no pointers by changing |
| // the type of the overflow field to uintptr in this case. |
| // See comment on hmap.overflow in runtime/map.go. |
| otyp := types.Types[types.TUNSAFEPTR] |
| if !elemtype.HasPointers() && !keytype.HasPointers() { |
| otyp = types.Types[types.TUINTPTR] |
| } |
| overflow := makefield("overflow", otyp) |
| field = append(field, overflow) |
| |
| // link up fields |
| bucket := types.NewStruct(types.NoPkg, field[:]) |
| bucket.SetNoalg(true) |
| types.CalcSize(bucket) |
| |
| // Check invariants that map code depends on. |
| if !types.IsComparable(t.Key()) { |
| base.Fatalf("unsupported map key type for %v", t) |
| } |
| if BUCKETSIZE < 8 { |
| base.Fatalf("bucket size too small for proper alignment") |
| } |
| if keytype.Align > BUCKETSIZE { |
| base.Fatalf("key align too big for %v", t) |
| } |
| if elemtype.Align > BUCKETSIZE { |
| base.Fatalf("elem align too big for %v", t) |
| } |
| if keytype.Width > MAXKEYSIZE { |
| base.Fatalf("key size to large for %v", t) |
| } |
| if elemtype.Width > MAXELEMSIZE { |
| base.Fatalf("elem size to large for %v", t) |
| } |
| if t.Key().Width > MAXKEYSIZE && !keytype.IsPtr() { |
| base.Fatalf("key indirect incorrect for %v", t) |
| } |
| if t.Elem().Width > MAXELEMSIZE && !elemtype.IsPtr() { |
| base.Fatalf("elem indirect incorrect for %v", t) |
| } |
| if keytype.Width%int64(keytype.Align) != 0 { |
| base.Fatalf("key size not a multiple of key align for %v", t) |
| } |
| if elemtype.Width%int64(elemtype.Align) != 0 { |
| base.Fatalf("elem size not a multiple of elem align for %v", t) |
| } |
| if bucket.Align%keytype.Align != 0 { |
| base.Fatalf("bucket align not multiple of key align %v", t) |
| } |
| if bucket.Align%elemtype.Align != 0 { |
| base.Fatalf("bucket align not multiple of elem align %v", t) |
| } |
| if keys.Offset%int64(keytype.Align) != 0 { |
| base.Fatalf("bad alignment of keys in bmap for %v", t) |
| } |
| if elems.Offset%int64(elemtype.Align) != 0 { |
| base.Fatalf("bad alignment of elems in bmap for %v", t) |
| } |
| |
| // Double-check that overflow field is final memory in struct, |
| // with no padding at end. |
| if overflow.Offset != bucket.Width-int64(types.PtrSize) { |
| base.Fatalf("bad offset of overflow in bmap for %v", t) |
| } |
| |
| t.MapType().Bucket = bucket |
| |
| bucket.StructType().Map = t |
| return bucket |
| } |
| |
| // MapType builds a type representing a Hmap structure for the given map type. |
| // Make sure this stays in sync with runtime/map.go. |
| func MapType(t *types.Type) *types.Type { |
| if t.MapType().Hmap != nil { |
| return t.MapType().Hmap |
| } |
| |
| bmap := MapBucketType(t) |
| |
| // build a struct: |
| // type hmap struct { |
| // count int |
| // flags uint8 |
| // B uint8 |
| // noverflow uint16 |
| // hash0 uint32 |
| // buckets *bmap |
| // oldbuckets *bmap |
| // nevacuate uintptr |
| // extra unsafe.Pointer // *mapextra |
| // } |
| // must match runtime/map.go:hmap. |
| fields := []*types.Field{ |
| makefield("count", types.Types[types.TINT]), |
| makefield("flags", types.Types[types.TUINT8]), |
| makefield("B", types.Types[types.TUINT8]), |
| makefield("noverflow", types.Types[types.TUINT16]), |
| makefield("hash0", types.Types[types.TUINT32]), // Used in walk.go for OMAKEMAP. |
| makefield("buckets", types.NewPtr(bmap)), // Used in walk.go for OMAKEMAP. |
| makefield("oldbuckets", types.NewPtr(bmap)), |
| makefield("nevacuate", types.Types[types.TUINTPTR]), |
| makefield("extra", types.Types[types.TUNSAFEPTR]), |
| } |
| |
| hmap := types.NewStruct(types.NoPkg, fields) |
| hmap.SetNoalg(true) |
| types.CalcSize(hmap) |
| |
| // The size of hmap should be 48 bytes on 64 bit |
| // and 28 bytes on 32 bit platforms. |
| if size := int64(8 + 5*types.PtrSize); hmap.Width != size { |
| base.Fatalf("hmap size not correct: got %d, want %d", hmap.Width, size) |
| } |
| |
| t.MapType().Hmap = hmap |
| hmap.StructType().Map = t |
| return hmap |
| } |
| |
| // MapIterType builds a type representing an Hiter structure for the given map type. |
| // Make sure this stays in sync with runtime/map.go. |
| func MapIterType(t *types.Type) *types.Type { |
| if t.MapType().Hiter != nil { |
| return t.MapType().Hiter |
| } |
| |
| hmap := MapType(t) |
| bmap := MapBucketType(t) |
| |
| // build a struct: |
| // type hiter struct { |
| // key *Key |
| // elem *Elem |
| // t unsafe.Pointer // *MapType |
| // h *hmap |
| // buckets *bmap |
| // bptr *bmap |
| // overflow unsafe.Pointer // *[]*bmap |
| // oldoverflow unsafe.Pointer // *[]*bmap |
| // startBucket uintptr |
| // offset uint8 |
| // wrapped bool |
| // B uint8 |
| // i uint8 |
| // bucket uintptr |
| // checkBucket uintptr |
| // } |
| // must match runtime/map.go:hiter. |
| fields := []*types.Field{ |
| makefield("key", types.NewPtr(t.Key())), // Used in range.go for TMAP. |
| makefield("elem", types.NewPtr(t.Elem())), // Used in range.go for TMAP. |
| makefield("t", types.Types[types.TUNSAFEPTR]), |
| makefield("h", types.NewPtr(hmap)), |
| makefield("buckets", types.NewPtr(bmap)), |
| makefield("bptr", types.NewPtr(bmap)), |
| makefield("overflow", types.Types[types.TUNSAFEPTR]), |
| makefield("oldoverflow", types.Types[types.TUNSAFEPTR]), |
| makefield("startBucket", types.Types[types.TUINTPTR]), |
| makefield("offset", types.Types[types.TUINT8]), |
| makefield("wrapped", types.Types[types.TBOOL]), |
| makefield("B", types.Types[types.TUINT8]), |
| makefield("i", types.Types[types.TUINT8]), |
| makefield("bucket", types.Types[types.TUINTPTR]), |
| makefield("checkBucket", types.Types[types.TUINTPTR]), |
| } |
| |
| // build iterator struct holding the above fields |
| hiter := types.NewStruct(types.NoPkg, fields) |
| hiter.SetNoalg(true) |
| types.CalcSize(hiter) |
| if hiter.Width != int64(12*types.PtrSize) { |
| base.Fatalf("hash_iter size not correct %d %d", hiter.Width, 12*types.PtrSize) |
| } |
| t.MapType().Hiter = hiter |
| hiter.StructType().Map = t |
| return hiter |
| } |
| |
| // methods returns the methods of the non-interface type t, sorted by name. |
| // Generates stub functions as needed. |
| func methods(t *types.Type) []*typeSig { |
| // method type |
| mt := types.ReceiverBaseType(t) |
| |
| if mt == nil { |
| return nil |
| } |
| typecheck.CalcMethods(mt) |
| |
| // type stored in interface word |
| it := t |
| |
| if !types.IsDirectIface(it) { |
| it = types.NewPtr(t) |
| } |
| |
| // make list of methods for t, |
| // generating code if necessary. |
| var ms []*typeSig |
| for _, f := range mt.AllMethods().Slice() { |
| if f.Sym == nil { |
| base.Fatalf("method with no sym on %v", mt) |
| } |
| if !f.IsMethod() { |
| base.Fatalf("non-method on %v method %v %v", mt, f.Sym, f) |
| } |
| if f.Type.Recv() == nil { |
| base.Fatalf("receiver with no type on %v method %v %v", mt, f.Sym, f) |
| } |
| if f.Nointerface() { |
| continue |
| } |
| |
| // get receiver type for this particular method. |
| // if pointer receiver but non-pointer t and |
| // this is not an embedded pointer inside a struct, |
| // method does not apply. |
| if !types.IsMethodApplicable(t, f) { |
| continue |
| } |
| |
| sig := &typeSig{ |
| name: f.Sym, |
| isym: methodWrapper(it, f), |
| tsym: methodWrapper(t, f), |
| type_: typecheck.NewMethodType(f.Type, t), |
| mtype: typecheck.NewMethodType(f.Type, nil), |
| } |
| ms = append(ms, sig) |
| } |
| |
| return ms |
| } |
| |
| // imethods returns the methods of the interface type t, sorted by name. |
| func imethods(t *types.Type) []*typeSig { |
| var methods []*typeSig |
| for _, f := range t.AllMethods().Slice() { |
| if f.Type.Kind() != types.TFUNC || f.Sym == nil { |
| continue |
| } |
| if f.Sym.IsBlank() { |
| base.Fatalf("unexpected blank symbol in interface method set") |
| } |
| if n := len(methods); n > 0 { |
| last := methods[n-1] |
| if !last.name.Less(f.Sym) { |
| base.Fatalf("sigcmp vs sortinter %v %v", last.name, f.Sym) |
| } |
| } |
| |
| sig := &typeSig{ |
| name: f.Sym, |
| mtype: f.Type, |
| type_: typecheck.NewMethodType(f.Type, nil), |
| } |
| methods = append(methods, sig) |
| |
| // NOTE(rsc): Perhaps an oversight that |
| // IfaceType.Method is not in the reflect data. |
| // Generate the method body, so that compiled |
| // code can refer to it. |
| methodWrapper(t, f) |
| } |
| |
| return methods |
| } |
| |
| func dimportpath(p *types.Pkg) { |
| if p.Pathsym != nil { |
| return |
| } |
| |
| // If we are compiling the runtime package, there are two runtime packages around |
| // -- localpkg and Pkgs.Runtime. We don't want to produce import path symbols for |
| // both of them, so just produce one for localpkg. |
| if base.Ctxt.Pkgpath == "runtime" && p == ir.Pkgs.Runtime { |
| return |
| } |
| |
| str := p.Path |
| if p == types.LocalPkg { |
| // Note: myimportpath != "", or else dgopkgpath won't call dimportpath. |
| str = base.Ctxt.Pkgpath |
| } |
| |
| s := base.Ctxt.Lookup("type..importpath." + p.Prefix + ".") |
| ot := dnameData(s, 0, str, "", nil, false) |
| objw.Global(s, int32(ot), obj.DUPOK|obj.RODATA) |
| s.Set(obj.AttrContentAddressable, true) |
| p.Pathsym = s |
| } |
| |
| func dgopkgpath(s *obj.LSym, ot int, pkg *types.Pkg) int { |
| if pkg == nil { |
| return objw.Uintptr(s, ot, 0) |
| } |
| |
| if pkg == types.LocalPkg && base.Ctxt.Pkgpath == "" { |
| // If we don't know the full import path of the package being compiled |
| // (i.e. -p was not passed on the compiler command line), emit a reference to |
| // type..importpath.""., which the linker will rewrite using the correct import path. |
| // Every package that imports this one directly defines the symbol. |
| // See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ. |
| ns := base.Ctxt.Lookup(`type..importpath."".`) |
| return objw.SymPtr(s, ot, ns, 0) |
| } |
| |
| dimportpath(pkg) |
| return objw.SymPtr(s, ot, pkg.Pathsym, 0) |
| } |
| |
| // dgopkgpathOff writes an offset relocation in s at offset ot to the pkg path symbol. |
| func dgopkgpathOff(s *obj.LSym, ot int, pkg *types.Pkg) int { |
| if pkg == nil { |
| return objw.Uint32(s, ot, 0) |
| } |
| if pkg == types.LocalPkg && base.Ctxt.Pkgpath == "" { |
| // If we don't know the full import path of the package being compiled |
| // (i.e. -p was not passed on the compiler command line), emit a reference to |
| // type..importpath.""., which the linker will rewrite using the correct import path. |
| // Every package that imports this one directly defines the symbol. |
| // See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ. |
| ns := base.Ctxt.Lookup(`type..importpath."".`) |
| return objw.SymPtrOff(s, ot, ns) |
| } |
| |
| dimportpath(pkg) |
| return objw.SymPtrOff(s, ot, pkg.Pathsym) |
| } |
| |
| // dnameField dumps a reflect.name for a struct field. |
| func dnameField(lsym *obj.LSym, ot int, spkg *types.Pkg, ft *types.Field) int { |
| if !types.IsExported(ft.Sym.Name) && ft.Sym.Pkg != spkg { |
| base.Fatalf("package mismatch for %v", ft.Sym) |
| } |
| nsym := dname(ft.Sym.Name, ft.Note, nil, types.IsExported(ft.Sym.Name)) |
| return objw.SymPtr(lsym, ot, nsym, 0) |
| } |
| |
| // 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<<29 { |
| base.Fatalf("name too long: %d %s...", len(name), name[:1024]) |
| } |
| 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 + nameLenLen + len(name) |
| if exported { |
| bits |= 1 << 0 |
| } |
| if len(tag) > 0 { |
| l += tagLenLen + len(tag) |
| bits |= 1 << 1 |
| } |
| if pkg != nil { |
| bits |= 1 << 2 |
| } |
| b := make([]byte, l) |
| b[0] = bits |
| copy(b[1:], nameLen[:nameLenLen]) |
| copy(b[1+nameLenLen:], name) |
| if len(tag) > 0 { |
| tb := b[1+nameLenLen+len(name):] |
| copy(tb, tagLen[:tagLenLen]) |
| copy(tb[tagLenLen:], tag) |
| } |
| |
| ot = int(s.WriteBytes(base.Ctxt, int64(ot), b)) |
| |
| if pkg != nil { |
| ot = dgopkgpathOff(s, ot, pkg) |
| } |
| |
| return ot |
| } |
| |
| var dnameCount int |
| |
| // dname creates a reflect.name for a struct field or method. |
| func dname(name, tag string, pkg *types.Pkg, exported bool) *obj.LSym { |
| // Write out data as "type.." to signal two things to the |
| // linker, first that when dynamically linking, the symbol |
| // should be moved to a relro section, and second that the |
| // contents should not be decoded as a type. |
| sname := "type..namedata." |
| if pkg == nil { |
| // In the common case, share data with other packages. |
| if name == "" { |
| if exported { |
| sname += "-noname-exported." + tag |
| } else { |
| sname += "-noname-unexported." + tag |
| } |
| } else { |
| if exported { |
| sname += name + "." + tag |
| } else { |
| sname += name + "-" + tag |
| } |
| } |
| } else { |
| sname = fmt.Sprintf(`%s"".%d`, sname, dnameCount) |
| dnameCount++ |
| } |
| s := base.Ctxt.Lookup(sname) |
| if len(s.P) > 0 { |
| return s |
| } |
| ot := dnameData(s, 0, name, tag, pkg, exported) |
| objw.Global(s, int32(ot), obj.DUPOK|obj.RODATA) |
| s.Set(obj.AttrContentAddressable, true) |
| return s |
| } |
| |
| // dextratype dumps the fields of a runtime.uncommontype. |
| // dataAdd is the offset in bytes after the header where the |
| // backing array of the []method field is written (by dextratypeData). |
| func dextratype(lsym *obj.LSym, ot int, t *types.Type, dataAdd int) int { |
| m := methods(t) |
| if t.Sym() == nil && len(m) == 0 { |
| return ot |
| } |
| noff := int(types.Rnd(int64(ot), int64(types.PtrSize))) |
| if noff != ot { |
| base.Fatalf("unexpected alignment in dextratype for %v", t) |
| } |
| |
| for _, a := range m { |
| writeType(a.type_) |
| } |
| |
| ot = dgopkgpathOff(lsym, ot, typePkg(t)) |
| |
| dataAdd += uncommonSize(t) |
| mcount := len(m) |
| if mcount != int(uint16(mcount)) { |
| base.Fatalf("too many methods on %v: %d", t, mcount) |
| } |
| xcount := sort.Search(mcount, func(i int) bool { return !types.IsExported(m[i].name.Name) }) |
| if dataAdd != int(uint32(dataAdd)) { |
| base.Fatalf("methods are too far away on %v: %d", t, dataAdd) |
| } |
| |
| ot = objw.Uint16(lsym, ot, uint16(mcount)) |
| ot = objw.Uint16(lsym, ot, uint16(xcount)) |
| ot = objw.Uint32(lsym, ot, uint32(dataAdd)) |
| ot = objw.Uint32(lsym, ot, 0) |
| return ot |
| } |
| |
| func typePkg(t *types.Type) *types.Pkg { |
| tsym := t.Sym() |
| if tsym == nil { |
| switch t.Kind() { |
| case types.TARRAY, types.TSLICE, types.TPTR, types.TCHAN: |
| if t.Elem() != nil { |
| tsym = t.Elem().Sym() |
| } |
| } |
| } |
| if tsym != nil && tsym.Pkg != types.BuiltinPkg { |
| return tsym.Pkg |
| } |
| return nil |
| } |
| |
| // dextratypeData dumps the backing array for the []method field of |
| // runtime.uncommontype. |
| func dextratypeData(lsym *obj.LSym, ot int, t *types.Type) int { |
| for _, a := range methods(t) { |
| // ../../../../runtime/type.go:/method |
| exported := types.IsExported(a.name.Name) |
| var pkg *types.Pkg |
| if !exported && a.name.Pkg != typePkg(t) { |
| pkg = a.name.Pkg |
| } |
| nsym := dname(a.name.Name, "", pkg, exported) |
| |
| ot = objw.SymPtrOff(lsym, ot, nsym) |
| ot = dmethodptrOff(lsym, ot, writeType(a.mtype)) |
| ot = dmethodptrOff(lsym, ot, a.isym) |
| ot = dmethodptrOff(lsym, ot, a.tsym) |
| } |
| return ot |
| } |
| |
| func dmethodptrOff(s *obj.LSym, ot int, x *obj.LSym) int { |
| objw.Uint32(s, ot, 0) |
| r := obj.Addrel(s) |
| r.Off = int32(ot) |
| r.Siz = 4 |
| r.Sym = x |
| r.Type = objabi.R_METHODOFF |
| return ot + 4 |
| } |
| |
| var kinds = []int{ |
| types.TINT: objabi.KindInt, |
| types.TUINT: objabi.KindUint, |
| types.TINT8: objabi.KindInt8, |
| types.TUINT8: objabi.KindUint8, |
| types.TINT16: objabi.KindInt16, |
| types.TUINT16: objabi.KindUint16, |
| types.TINT32: objabi.KindInt32, |
| types.TUINT32: objabi.KindUint32, |
| types.TINT64: objabi.KindInt64, |
| types.TUINT64: objabi.KindUint64, |
| types.TUINTPTR: objabi.KindUintptr, |
| types.TFLOAT32: objabi.KindFloat32, |
| types.TFLOAT64: objabi.KindFloat64, |
| types.TBOOL: objabi.KindBool, |
| types.TSTRING: objabi.KindString, |
| types.TPTR: objabi.KindPtr, |
| types.TSTRUCT: objabi.KindStruct, |
| types.TINTER: objabi.KindInterface, |
| types.TCHAN: objabi.KindChan, |
| types.TMAP: objabi.KindMap, |
| types.TARRAY: objabi.KindArray, |
| types.TSLICE: objabi.KindSlice, |
| types.TFUNC: objabi.KindFunc, |
| types.TCOMPLEX64: objabi.KindComplex64, |
| types.TCOMPLEX128: objabi.KindComplex128, |
| types.TUNSAFEPTR: objabi.KindUnsafePointer, |
| } |
| |
| // tflag is documented in reflect/type.go. |
| // |
| // tflag values must be kept in sync with copies in: |
| // cmd/compile/internal/gc/reflect.go |
| // cmd/link/internal/ld/decodesym.go |
| // reflect/type.go |
| // runtime/type.go |
| const ( |
| tflagUncommon = 1 << 0 |
| tflagExtraStar = 1 << 1 |
| tflagNamed = 1 << 2 |
| tflagRegularMemory = 1 << 3 |
| ) |
| |
| var ( |
| memhashvarlen *obj.LSym |
| memequalvarlen *obj.LSym |
| ) |
| |
| // dcommontype dumps the contents of a reflect.rtype (runtime._type). |
| func dcommontype(lsym *obj.LSym, t *types.Type) int { |
| types.CalcSize(t) |
| eqfunc := geneq(t) |
| |
| sptrWeak := true |
| var sptr *obj.LSym |
| if !t.IsPtr() || t.IsPtrElem() { |
| tptr := types.NewPtr(t) |
| if t.Sym() != nil || methods(tptr) != nil { |
| sptrWeak = false |
| } |
| sptr = writeType(tptr) |
| } |
| |
| gcsym, useGCProg, ptrdata := dgcsym(t, true) |
| delete(gcsymset, t) |
| |
| // ../../../../reflect/type.go:/^type.rtype |
| // actual type structure |
| // type rtype struct { |
| // size uintptr |
| // ptrdata uintptr |
| // hash uint32 |
| // tflag tflag |
| // align uint8 |
| // fieldAlign uint8 |
| // kind uint8 |
| // equal func(unsafe.Pointer, unsafe.Pointer) bool |
| // gcdata *byte |
| // str nameOff |
| // ptrToThis typeOff |
| // } |
| ot := 0 |
| ot = objw.Uintptr(lsym, ot, uint64(t.Width)) |
| ot = objw.Uintptr(lsym, ot, uint64(ptrdata)) |
| ot = objw.Uint32(lsym, ot, types.TypeHash(t)) |
| |
| var tflag uint8 |
| if uncommonSize(t) != 0 { |
| tflag |= tflagUncommon |
| } |
| if t.Sym() != nil && t.Sym().Name != "" { |
| tflag |= tflagNamed |
| } |
| if isRegularMemory(t) { |
| tflag |= tflagRegularMemory |
| } |
| |
| exported := false |
| p := t.LongString() |
| // If we're writing out type T, |
| // we are very likely to write out type *T as well. |
| // Use the string "*T"[1:] for "T", so that the two |
| // share storage. This is a cheap way to reduce the |
| // amount of space taken up by reflect strings. |
| if !strings.HasPrefix(p, "*") { |
| p = "*" + p |
| tflag |= tflagExtraStar |
| if t.Sym() != nil { |
| exported = types.IsExported(t.Sym().Name) |
| } |
| } else { |
| if t.Elem() != nil && t.Elem().Sym() != nil { |
| exported = types.IsExported(t.Elem().Sym().Name) |
| } |
| } |
| |
| ot = objw.Uint8(lsym, ot, tflag) |
| |
| // runtime (and common sense) expects alignment to be a power of two. |
| i := int(t.Align) |
| |
| if i == 0 { |
| i = 1 |
| } |
| if i&(i-1) != 0 { |
| base.Fatalf("invalid alignment %d for %v", t.Align, t) |
| } |
| ot = objw.Uint8(lsym, ot, t.Align) // align |
| ot = objw.Uint8(lsym, ot, t.Align) // fieldAlign |
| |
| i = kinds[t.Kind()] |
| if types.IsDirectIface(t) { |
| i |= objabi.KindDirectIface |
| } |
| if useGCProg { |
| i |= objabi.KindGCProg |
| } |
| ot = objw.Uint8(lsym, ot, uint8(i)) // kind |
| if eqfunc != nil { |
| ot = objw.SymPtr(lsym, ot, eqfunc, 0) // equality function |
| } else { |
| ot = objw.Uintptr(lsym, ot, 0) // type we can't do == with |
| } |
| ot = objw.SymPtr(lsym, ot, gcsym, 0) // gcdata |
| |
| nsym := dname(p, "", nil, exported) |
| ot = objw.SymPtrOff(lsym, ot, nsym) // str |
| // ptrToThis |
| if sptr == nil { |
| ot = objw.Uint32(lsym, ot, 0) |
| } else if sptrWeak { |
| ot = objw.SymPtrWeakOff(lsym, ot, sptr) |
| } else { |
| ot = objw.SymPtrOff(lsym, ot, sptr) |
| } |
| |
| return ot |
| } |
| |
| // TrackSym returns the symbol for tracking use of field/method f, assumed |
| // to be a member of struct/interface type t. |
| func TrackSym(t *types.Type, f *types.Field) *obj.LSym { |
| return base.PkgLinksym("go.track", t.ShortString()+"."+f.Sym.Name, obj.ABI0) |
| } |
| |
| func TypeSymPrefix(prefix string, t *types.Type) *types.Sym { |
| p := prefix + "." + t.ShortString() |
| s := types.TypeSymLookup(p) |
| |
| // This function is for looking up type-related generated functions |
| // (e.g. eq and hash). Make sure they are indeed generated. |
| signatmu.Lock() |
| NeedRuntimeType(t) |
| signatmu.Unlock() |
| |
| //print("algsym: %s -> %+S\n", p, s); |
| |
| return s |
| } |
| |
| func TypeSym(t *types.Type) *types.Sym { |
| if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() { |
| base.Fatalf("TypeSym %v", t) |
| } |
| if t.Kind() == types.TFUNC && t.Recv() != nil { |
| base.Fatalf("misuse of method type: %v", t) |
| } |
| s := types.TypeSym(t) |
| signatmu.Lock() |
| NeedRuntimeType(t) |
| signatmu.Unlock() |
| return s |
| } |
| |
| func TypeLinksymPrefix(prefix string, t *types.Type) *obj.LSym { |
| return TypeSymPrefix(prefix, t).Linksym() |
| } |
| |
| func TypeLinksymLookup(name string) *obj.LSym { |
| return types.TypeSymLookup(name).Linksym() |
| } |
| |
| func TypeLinksym(t *types.Type) *obj.LSym { |
| return TypeSym(t).Linksym() |
| } |
| |
| func TypePtr(t *types.Type) *ir.AddrExpr { |
| n := ir.NewLinksymExpr(base.Pos, TypeLinksym(t), types.Types[types.TUINT8]) |
| return typecheck.Expr(typecheck.NodAddr(n)).(*ir.AddrExpr) |
| } |
| |
| func ITabAddr(t, itype *types.Type) *ir.AddrExpr { |
| if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() || !itype.IsInterface() || itype.IsEmptyInterface() { |
| base.Fatalf("ITabAddr(%v, %v)", t, itype) |
| } |
| s, existed := ir.Pkgs.Itab.LookupOK(t.ShortString() + "," + itype.ShortString()) |
| if !existed { |
| itabs = append(itabs, itabEntry{t: t, itype: itype, lsym: s.Linksym()}) |
| } |
| |
| lsym := s.Linksym() |
| n := ir.NewLinksymExpr(base.Pos, lsym, types.Types[types.TUINT8]) |
| return typecheck.Expr(typecheck.NodAddr(n)).(*ir.AddrExpr) |
| } |
| |
| // needkeyupdate reports whether map updates with t as a key |
| // need the key to be updated. |
| func needkeyupdate(t *types.Type) bool { |
| switch t.Kind() { |
| case types.TBOOL, types.TINT, types.TUINT, types.TINT8, types.TUINT8, types.TINT16, types.TUINT16, types.TINT32, types.TUINT32, |
| types.TINT64, types.TUINT64, types.TUINTPTR, types.TPTR, types.TUNSAFEPTR, types.TCHAN: |
| return false |
| |
| case types.TFLOAT32, types.TFLOAT64, types.TCOMPLEX64, types.TCOMPLEX128, // floats and complex can be +0/-0 |
| types.TINTER, |
| types.TSTRING: // strings might have smaller backing stores |
| return true |
| |
| case types.TARRAY: |
| return needkeyupdate(t.Elem()) |
| |
| case types.TSTRUCT: |
| for _, t1 := range t.Fields().Slice() { |
| if needkeyupdate(t1.Type) { |
| return true |
| } |
| } |
| return false |
| |
| default: |
| base.Fatalf("bad type for map key: %v", t) |
| return true |
| } |
| } |
| |
| // hashMightPanic reports whether the hash of a map key of type t might panic. |
| func hashMightPanic(t *types.Type) bool { |
| switch t.Kind() { |
| case types.TINTER: |
| return true |
| |
| case types.TARRAY: |
| return hashMightPanic(t.Elem()) |
| |
| case types.TSTRUCT: |
| for _, t1 := range t.Fields().Slice() { |
| if hashMightPanic(t1.Type) { |
| return true |
| } |
| } |
| return false |
| |
| default: |
| return false |
| } |
| } |
| |
| // formalType replaces byte and rune aliases with real types. |
| // They've been separate internally to make error messages |
| // better, but we have to merge them in the reflect tables. |
| func formalType(t *types.Type) *types.Type { |
| if t == types.ByteType || t == types.RuneType { |
| return types.Types[t.Kind()] |
| } |
| return t |
| } |
| |
| func writeType(t *types.Type) *obj.LSym { |
| t = formalType(t) |
| if t.IsUntyped() { |
| base.Fatalf("writeType %v", t) |
| } |
| |
| s := types.TypeSym(t) |
| lsym := s.Linksym() |
| if s.Siggen() { |
| return lsym |
| } |
| s.SetSiggen(true) |
| |
| // special case (look for runtime below): |
| // when compiling package runtime, |
| // emit the type structures for int, float, etc. |
| tbase := t |
| |
| if t.IsPtr() && t.Sym() == nil && t.Elem().Sym() != nil { |
| tbase = t.Elem() |
| } |
| dupok := 0 |
| if tbase.Sym() == nil { |
| dupok = obj.DUPOK |
| } |
| |
| if base.Ctxt.Pkgpath != "runtime" || (tbase != types.Types[tbase.Kind()] && tbase != types.ByteType && tbase != types.RuneType && tbase != types.ErrorType) { // int, float, etc |
| // named types from other files are defined only by those files |
| if tbase.Sym() != nil && tbase.Sym().Pkg != types.LocalPkg { |
| if i := typecheck.BaseTypeIndex(t); i >= 0 { |
| lsym.Pkg = tbase.Sym().Pkg.Prefix |
| lsym.SymIdx = int32(i) |
| lsym.Set(obj.AttrIndexed, true) |
| } |
| return lsym |
| } |
| // TODO(mdempsky): Investigate whether this can happen. |
| if tbase.Kind() == types.TFORW { |
| return lsym |
| } |
| } |
| |
| ot := 0 |
| switch t.Kind() { |
| default: |
| ot = dcommontype(lsym, t) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| case types.TARRAY: |
| // ../../../../runtime/type.go:/arrayType |
| s1 := writeType(t.Elem()) |
| t2 := types.NewSlice(t.Elem()) |
| s2 := writeType(t2) |
| ot = dcommontype(lsym, t) |
| ot = objw.SymPtr(lsym, ot, s1, 0) |
| ot = objw.SymPtr(lsym, ot, s2, 0) |
| ot = objw.Uintptr(lsym, ot, uint64(t.NumElem())) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| case types.TSLICE: |
| // ../../../../runtime/type.go:/sliceType |
| s1 := writeType(t.Elem()) |
| ot = dcommontype(lsym, t) |
| ot = objw.SymPtr(lsym, ot, s1, 0) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| case types.TCHAN: |
| // ../../../../runtime/type.go:/chanType |
| s1 := writeType(t.Elem()) |
| ot = dcommontype(lsym, t) |
| ot = objw.SymPtr(lsym, ot, s1, 0) |
| ot = objw.Uintptr(lsym, ot, uint64(t.ChanDir())) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| case types.TFUNC: |
| for _, t1 := range t.Recvs().Fields().Slice() { |
| writeType(t1.Type) |
| } |
| isddd := false |
| for _, t1 := range t.Params().Fields().Slice() { |
| isddd = t1.IsDDD() |
| writeType(t1.Type) |
| } |
| for _, t1 := range t.Results().Fields().Slice() { |
| writeType(t1.Type) |
| } |
| |
| ot = dcommontype(lsym, t) |
| inCount := t.NumRecvs() + t.NumParams() |
| outCount := t.NumResults() |
| if isddd { |
| outCount |= 1 << 15 |
| } |
| ot = objw.Uint16(lsym, ot, uint16(inCount)) |
| ot = objw.Uint16(lsym, ot, uint16(outCount)) |
| if types.PtrSize == 8 { |
| ot += 4 // align for *rtype |
| } |
| |
| dataAdd := (inCount + t.NumResults()) * types.PtrSize |
| ot = dextratype(lsym, ot, t, dataAdd) |
| |
| // Array of rtype pointers follows funcType. |
| for _, t1 := range t.Recvs().Fields().Slice() { |
| ot = objw.SymPtr(lsym, ot, writeType(t1.Type), 0) |
| } |
| for _, t1 := range t.Params().Fields().Slice() { |
| ot = objw.SymPtr(lsym, ot, writeType(t1.Type), 0) |
| } |
| for _, t1 := range t.Results().Fields().Slice() { |
| ot = objw.SymPtr(lsym, ot, writeType(t1.Type), 0) |
| } |
| |
| case types.TINTER: |
| m := imethods(t) |
| n := len(m) |
| for _, a := range m { |
| writeType(a.type_) |
| } |
| |
| // ../../../../runtime/type.go:/interfaceType |
| ot = dcommontype(lsym, t) |
| |
| var tpkg *types.Pkg |
| if t.Sym() != nil && t != types.Types[t.Kind()] && t != types.ErrorType { |
| tpkg = t.Sym().Pkg |
| } |
| ot = dgopkgpath(lsym, ot, tpkg) |
| |
| ot = objw.SymPtr(lsym, ot, lsym, ot+3*types.PtrSize+uncommonSize(t)) |
| ot = objw.Uintptr(lsym, ot, uint64(n)) |
| ot = objw.Uintptr(lsym, ot, uint64(n)) |
| dataAdd := imethodSize() * n |
| ot = dextratype(lsym, ot, t, dataAdd) |
| |
| for _, a := range m { |
| // ../../../../runtime/type.go:/imethod |
| exported := types.IsExported(a.name.Name) |
| var pkg *types.Pkg |
| if !exported && a.name.Pkg != tpkg { |
| pkg = a.name.Pkg |
| } |
| nsym := dname(a.name.Name, "", pkg, exported) |
| |
| ot = objw.SymPtrOff(lsym, ot, nsym) |
| ot = objw.SymPtrOff(lsym, ot, writeType(a.type_)) |
| } |
| |
| // ../../../../runtime/type.go:/mapType |
| case types.TMAP: |
| s1 := writeType(t.Key()) |
| s2 := writeType(t.Elem()) |
| s3 := writeType(MapBucketType(t)) |
| hasher := genhash(t.Key()) |
| |
| ot = dcommontype(lsym, t) |
| ot = objw.SymPtr(lsym, ot, s1, 0) |
| ot = objw.SymPtr(lsym, ot, s2, 0) |
| ot = objw.SymPtr(lsym, ot, s3, 0) |
| ot = objw.SymPtr(lsym, ot, hasher, 0) |
| var flags uint32 |
| // Note: flags must match maptype accessors in ../../../../runtime/type.go |
| // and maptype builder in ../../../../reflect/type.go:MapOf. |
| if t.Key().Width > MAXKEYSIZE { |
| ot = objw.Uint8(lsym, ot, uint8(types.PtrSize)) |
| flags |= 1 // indirect key |
| } else { |
| ot = objw.Uint8(lsym, ot, uint8(t.Key().Width)) |
| } |
| |
| if t.Elem().Width > MAXELEMSIZE { |
| ot = objw.Uint8(lsym, ot, uint8(types.PtrSize)) |
| flags |= 2 // indirect value |
| } else { |
| ot = objw.Uint8(lsym, ot, uint8(t.Elem().Width)) |
| } |
| ot = objw.Uint16(lsym, ot, uint16(MapBucketType(t).Width)) |
| if types.IsReflexive(t.Key()) { |
| flags |= 4 // reflexive key |
| } |
| if needkeyupdate(t.Key()) { |
| flags |= 8 // need key update |
| } |
| if hashMightPanic(t.Key()) { |
| flags |= 16 // hash might panic |
| } |
| ot = objw.Uint32(lsym, ot, flags) |
| ot = dextratype(lsym, ot, t, 0) |
| if u := t.Underlying(); u != t { |
| // If t is a named map type, also keep the underlying map |
| // type live in the binary. This is important to make sure that |
| // a named map and that same map cast to its underlying type via |
| // reflection, use the same hash function. See issue 37716. |
| r := obj.Addrel(lsym) |
| r.Sym = writeType(u) |
| r.Type = objabi.R_KEEP |
| } |
| |
| case types.TPTR: |
| if t.Elem().Kind() == types.TANY { |
| // ../../../../runtime/type.go:/UnsafePointerType |
| ot = dcommontype(lsym, t) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| break |
| } |
| |
| // ../../../../runtime/type.go:/ptrType |
| s1 := writeType(t.Elem()) |
| |
| ot = dcommontype(lsym, t) |
| ot = objw.SymPtr(lsym, ot, s1, 0) |
| ot = dextratype(lsym, ot, t, 0) |
| |
| // ../../../../runtime/type.go:/structType |
| // for security, only the exported fields. |
| case types.TSTRUCT: |
| fields := t.Fields().Slice() |
| for _, t1 := range fields { |
| writeType(t1.Type) |
| } |
| |
| // All non-exported struct field names within a struct |
| // type must originate from a single package. By |
| // identifying and recording that package within the |
| // struct type descriptor, we can omit that |
| // information from the field descriptors. |
| var spkg *types.Pkg |
| for _, f := range fields { |
| if !types.IsExported(f.Sym.Name) { |
| spkg = f.Sym.Pkg |
| break |
| } |
| } |
| |
| ot = dcommontype(lsym, t) |
| ot = dgopkgpath(lsym, ot, spkg) |
| ot = objw.SymPtr(lsym, ot, lsym, ot+3*types.PtrSize+uncommonSize(t)) |
| ot = objw.Uintptr(lsym, ot, uint64(len(fields))) |
| ot = objw.Uintptr(lsym, ot, uint64(len(fields))) |
| |
| dataAdd := len(fields) * structfieldSize() |
| ot = dextratype(lsym, ot, t, dataAdd) |
| |
| for _, f := range fields { |
| // ../../../../runtime/type.go:/structField |
| ot = dnameField(lsym, ot, spkg, f) |
| ot = objw.SymPtr(lsym, ot, writeType(f.Type), 0) |
| offsetAnon := uint64(f.Offset) << 1 |
| if offsetAnon>>1 != uint64(f.Offset) { |
| base.Fatalf("%v: bad field offset for %s", t, f.Sym.Name) |
| } |
| if f.Embedded != 0 { |
| offsetAnon |= 1 |
| } |
| ot = objw.Uintptr(lsym, ot, offsetAnon) |
| } |
| } |
| |
| ot = dextratypeData(lsym, ot, t) |
| objw.Global(lsym, int32(ot), int16(dupok|obj.RODATA)) |
| |
| // The linker will leave a table of all the typelinks for |
| // types in the binary, so the runtime can find them. |
| // |
| // When buildmode=shared, all types are in typelinks so the |
| // runtime can deduplicate type pointers. |
| keep := base.Ctxt.Flag_dynlink |
| if !keep && t.Sym() == nil { |
| // For an unnamed type, we only need the link if the type can |
| // be created at run time by reflect.PtrTo and similar |
| // functions. If the type exists in the program, those |
| // functions must return the existing type structure rather |
| // than creating a new one. |
| switch t.Kind() { |
| case types.TPTR, types.TARRAY, types.TCHAN, types.TFUNC, types.TMAP, types.TSLICE, types.TSTRUCT: |
| keep = true |
| } |
| } |
| // Do not put Noalg types in typelinks. See issue #22605. |
| if types.TypeHasNoAlg(t) { |
| keep = false |
| } |
| lsym.Set(obj.AttrMakeTypelink, keep) |
| |
| return lsym |
| } |
| |
| // InterfaceMethodOffset returns the offset of the i-th method in the interface |
| // type descriptor, ityp. |
| func InterfaceMethodOffset(ityp *types.Type, i int64) int64 { |
| // interface type descriptor layout is struct { |
| // _type // commonSize |
| // pkgpath // 1 word |
| // []imethod // 3 words (pointing to [...]imethod below) |
| // uncommontype // uncommonSize |
| // [...]imethod |
| // } |
| // The size of imethod is 8. |
| return int64(commonSize()+4*types.PtrSize+uncommonSize(ityp)) + i*8 |
| } |
| |
| // for each itabEntry, gather the methods on |
| // the concrete type that implement the interface |
| func CompileITabs() { |
| for i := range itabs { |
| tab := &itabs[i] |
| methods := genfun(tab.t, tab.itype) |
| if len(methods) == 0 { |
| continue |
| } |
| tab.entries = methods |
| } |
| } |
| |
| // for the given concrete type and interface |
| // type, return the (sorted) set of methods |
| // on the concrete type that implement the interface |
| func genfun(t, it *types.Type) []*obj.LSym { |
| if t == nil || it == nil { |
| return nil |
| } |
| sigs := imethods(it) |
| methods := methods(t) |
| out := make([]*obj.LSym, 0, len(sigs)) |
| // TODO(mdempsky): Short circuit before calling methods(t)? |
| // See discussion on CL 105039. |
| if len(sigs) == 0 { |
| return nil |
| } |
| |
| // both sigs and methods are sorted by name, |
| // so we can find the intersect in a single pass |
| for _, m := range methods { |
| if m.name == sigs[0].name { |
| out = append(out, m.isym) |
| sigs = sigs[1:] |
| if len(sigs) == 0 { |
| break |
| } |
| } |
| } |
| |
| if len(sigs) != 0 { |
| base.Fatalf("incomplete itab") |
| } |
| |
| return out |
| } |
| |
| // ITabSym uses the information gathered in |
| // CompileITabs to de-virtualize interface methods. |
| // Since this is called by the SSA backend, it shouldn't |
| // generate additional Nodes, Syms, etc. |
| func ITabSym(it *obj.LSym, offset int64) *obj.LSym { |
| var syms []*obj.LSym |
| if it == nil { |
| return nil |
| } |
| |
| for i := range itabs { |
| e := &itabs[i] |
| if e.lsym == it { |
| syms = e.entries |
| break |
| } |
| } |
| if syms == nil { |
| return nil |
| } |
| |
| // keep this arithmetic in sync with *itab layout |
| methodnum := int((offset - 2*int64(types.PtrSize) - 8) / int64(types.PtrSize)) |
| if methodnum >= len(syms) { |
| return nil |
| } |
| return syms[methodnum] |
| } |
| |
| // NeedRuntimeType ensures that a runtime type descriptor is emitted for t. |
| func NeedRuntimeType(t *types.Type) { |
| if t.HasTParam() { |
| // Generic types don't have a runtime type descriptor (but will |
| // have a dictionary) |
| return |
| } |
| if _, ok := signatset[t]; !ok { |
| signatset[t] = struct{}{} |
| signatslice = append(signatslice, t) |
| } |
| } |
| |
| func WriteRuntimeTypes() { |
| // Process signatset. Use a loop, as writeType adds |
| // entries to signatset while it is being processed. |
| signats := make([]typeAndStr, len(signatslice)) |
| for len(signatslice) > 0 { |
| signats = signats[:0] |
| // Transfer entries to a slice and sort, for reproducible builds. |
| for _, t := range signatslice { |
| signats = append(signats, typeAndStr{t: t, short: types.TypeSymName(t), regular: t.String()}) |
| delete(signatset, t) |
| } |
| signatslice = signatslice[:0] |
| sort.Sort(typesByString(signats)) |
| for _, ts := range signats { |
| t := ts.t |
| writeType(t) |
| if t.Sym() != nil { |
| writeType(types.NewPtr(t)) |
| } |
| } |
| } |
| |
| // Emit GC data symbols. |
| gcsyms := make([]typeAndStr, 0, len(gcsymset)) |
| for t := range gcsymset { |
| gcsyms = append(gcsyms, typeAndStr{t: t, short: types.TypeSymName(t), regular: t.String()}) |
| } |
| sort.Sort(typesByString(gcsyms)) |
| for _, ts := range gcsyms { |
| dgcsym(ts.t, true) |
| } |
| } |
| |
| func WriteTabs() { |
| // process itabs |
| for _, i := range itabs { |
| // dump empty itab symbol into i.sym |
| // type itab struct { |
| // inter *interfacetype |
| // _type *_type |
| // hash uint32 |
| // _ [4]byte |
| // fun [1]uintptr // variable sized |
| // } |
| o := objw.SymPtr(i.lsym, 0, writeType(i.itype), 0) |
| o = objw.SymPtr(i.lsym, o, writeType(i.t), 0) |
| o = objw.Uint32(i.lsym, o, types.TypeHash(i.t)) // copy of type hash |
| o += 4 // skip unused field |
| for _, fn := range genfun(i.t, i.itype) { |
| o = objw.SymPtrWeak(i.lsym, o, fn, 0) // method pointer for each method |
| } |
| // Nothing writes static itabs, so they are read only. |
| objw.Global(i.lsym, int32(o), int16(obj.DUPOK|obj.RODATA)) |
| i.lsym.Set(obj.AttrContentAddressable, true) |
| } |
| |
| // process ptabs |
| if types.LocalPkg.Name == "main" && len(ptabs) > 0 { |
| ot := 0 |
| s := base.Ctxt.Lookup("go.plugin.tabs") |
| for _, p := range ptabs { |
| // Dump ptab symbol into go.pluginsym package. |
| // |
| // type ptab struct { |
| // name nameOff |
| // typ typeOff // pointer to symbol |
| // } |
| nsym := dname(p.Sym().Name, "", nil, true) |
| t := p.Type() |
| if p.Class != ir.PFUNC { |
| t = types.NewPtr(t) |
| } |
| tsym := writeType(t) |
| ot = objw.SymPtrOff(s, ot, nsym) |
| ot = objw.SymPtrOff(s, ot, tsym) |
| // Plugin exports symbols as interfaces. Mark their types |
| // as UsedInIface. |
| tsym.Set(obj.AttrUsedInIface, true) |
| } |
| objw.Global(s, int32(ot), int16(obj.RODATA)) |
| |
| ot = 0 |
| s = base.Ctxt.Lookup("go.plugin.exports") |
| for _, p := range ptabs { |
| ot = objw.SymPtr(s, ot, p.Linksym(), 0) |
| } |
| objw.Global(s, int32(ot), int16(obj.RODATA)) |
| } |
| } |
| |
| func WriteImportStrings() { |
| // generate import strings for imported packages |
| for _, p := range types.ImportedPkgList() { |
| dimportpath(p) |
| } |
| } |
| |
| func WriteBasicTypes() { |
| // do basic types if compiling package runtime. |
| // they have to be in at least one package, |
| // and runtime is always loaded implicitly, |
| // so this is as good as any. |
| // another possible choice would be package main, |
| // but using runtime means fewer copies in object files. |
| if base.Ctxt.Pkgpath == "runtime" { |
| for i := types.Kind(1); i <= types.TBOOL; i++ { |
| writeType(types.NewPtr(types.Types[i])) |
| } |
| writeType(types.NewPtr(types.Types[types.TSTRING])) |
| writeType(types.NewPtr(types.Types[types.TUNSAFEPTR])) |
| |
| // emit type structs for error and func(error) string. |
| // The latter is the type of an auto-generated wrapper. |
| writeType(types.NewPtr(types.ErrorType)) |
| |
| writeType(types.NewSignature(types.NoPkg, nil, nil, []*types.Field{ |
| types.NewField(base.Pos, nil, types.ErrorType), |
| }, []*types.Field{ |
| types.NewField(base.Pos, nil, types.Types[types.TSTRING]), |
| })) |
| |
| // add paths for runtime and main, which 6l imports implicitly. |
| dimportpath(ir.Pkgs.Runtime) |
| |
| if base.Flag.Race { |
| dimportpath(types.NewPkg("runtime/race", "")) |
| } |
| if base.Flag.MSan { |
| dimportpath(types.NewPkg("runtime/msan", "")) |
| } |
| |
| dimportpath(types.NewPkg("main", "")) |
| } |
| } |
| |
| type typeAndStr struct { |
| t *types.Type |
| short string |
| regular string |
| } |
| |
| type typesByString []typeAndStr |
| |
| func (a typesByString) Len() int { return len(a) } |
| func (a typesByString) Less(i, j int) bool { |
| if a[i].short != a[j].short { |
| return a[i].short < a[j].short |
| } |
| // When the only difference between the types is whether |
| // they refer to byte or uint8, such as **byte vs **uint8, |
| // the types' ShortStrings can be identical. |
| // To preserve deterministic sort ordering, sort these by String(). |
| if a[i].regular != a[j].regular { |
| return a[i].regular < a[j].regular |
| } |
| // Identical anonymous interfaces defined in different locations |
| // will be equal for the above checks, but different in DWARF output. |
| // Sort by source position to ensure deterministic order. |
| // See issues 27013 and 30202. |
| if a[i].t.Kind() == types.TINTER && a[i].t.AllMethods().Len() > 0 { |
| return a[i].t.AllMethods().Index(0).Pos.Before(a[j].t.AllMethods().Index(0).Pos) |
| } |
| return false |
| } |
| func (a typesByString) Swap(i, j int) { a[i], a[j] = a[j], a[i] } |
| |
| // maxPtrmaskBytes is the maximum length of a GC ptrmask bitmap, |
| // which holds 1-bit entries describing where pointers are in a given type. |
| // Above this length, the GC information is recorded as a GC program, |
| // which can express repetition compactly. In either form, the |
| // information is used by the runtime to initialize the heap bitmap, |
| // and for large types (like 128 or more words), they are roughly the |
| // same speed. GC programs are never much larger and often more |
| // compact. (If large arrays are involved, they can be arbitrarily |
| // more compact.) |
| // |
| // The cutoff must be large enough that any allocation large enough to |
| // use a GC program is large enough that it does not share heap bitmap |
| // bytes with any other objects, allowing the GC program execution to |
| // assume an aligned start and not use atomic operations. In the current |
| // runtime, this means all malloc size classes larger than the cutoff must |
| // be multiples of four words. On 32-bit systems that's 16 bytes, and |
| // all size classes >= 16 bytes are 16-byte aligned, so no real constraint. |
| // On 64-bit systems, that's 32 bytes, and 32-byte alignment is guaranteed |
| // for size classes >= 256 bytes. On a 64-bit system, 256 bytes allocated |
| // is 32 pointers, the bits for which fit in 4 bytes. So maxPtrmaskBytes |
| // must be >= 4. |
| // |
| // We used to use 16 because the GC programs do have some constant overhead |
| // to get started, and processing 128 pointers seems to be enough to |
| // amortize that overhead well. |
| // |
| // To make sure that the runtime's chansend can call typeBitsBulkBarrier, |
| // we raised the limit to 2048, so that even 32-bit systems are guaranteed to |
| // use bitmaps for objects up to 64 kB in size. |
| // |
| // Also known to reflect/type.go. |
| // |
| const maxPtrmaskBytes = 2048 |
| |
| // GCSym returns a data symbol containing GC information for type t, along |
| // with a boolean reporting whether the UseGCProg bit should be set in the |
| // type kind, and the ptrdata field to record in the reflect type information. |
| // GCSym may be called in concurrent backend, so it does not emit the symbol |
| // content. |
| func GCSym(t *types.Type) (lsym *obj.LSym, useGCProg bool, ptrdata int64) { |
| // Record that we need to emit the GC symbol. |
| gcsymmu.Lock() |
| if _, ok := gcsymset[t]; !ok { |
| gcsymset[t] = struct{}{} |
| } |
| gcsymmu.Unlock() |
| |
| return dgcsym(t, false) |
| } |
| |
| // dgcsym returns a data symbol containing GC information for type t, along |
| // with a boolean reporting whether the UseGCProg bit should be set in the |
| // type kind, and the ptrdata field to record in the reflect type information. |
| // When write is true, it writes the symbol data. |
| func dgcsym(t *types.Type, write bool) (lsym *obj.LSym, useGCProg bool, ptrdata int64) { |
| ptrdata = types.PtrDataSize(t) |
| if ptrdata/int64(types.PtrSize) <= maxPtrmaskBytes*8 { |
| lsym = dgcptrmask(t, write) |
| return |
| } |
| |
| useGCProg = true |
| lsym, ptrdata = dgcprog(t, write) |
| return |
| } |
| |
| // dgcptrmask emits and returns the symbol containing a pointer mask for type t. |
| func dgcptrmask(t *types.Type, write bool) *obj.LSym { |
| ptrmask := make([]byte, (types.PtrDataSize(t)/int64(types.PtrSize)+7)/8) |
| fillptrmask(t, ptrmask) |
| p := fmt.Sprintf("runtime.gcbits.%x", ptrmask) |
| |
| lsym := base.Ctxt.Lookup(p) |
| if write && !lsym.OnList() { |
| for i, x := range ptrmask { |
| objw.Uint8(lsym, i, x) |
| } |
| objw.Global(lsym, int32(len(ptrmask)), obj.DUPOK|obj.RODATA|obj.LOCAL) |
| lsym.Set(obj.AttrContentAddressable, true) |
| } |
| return lsym |
| } |
| |
| // fillptrmask fills in ptrmask with 1s corresponding to the |
| // word offsets in t that hold pointers. |
| // ptrmask is assumed to fit at least types.PtrDataSize(t)/PtrSize bits. |
| func fillptrmask(t *types.Type, ptrmask []byte) { |
| for i := range ptrmask { |
| ptrmask[i] = 0 |
| } |
| if !t.HasPointers() { |
| return |
| } |
| |
| vec := bitvec.New(8 * int32(len(ptrmask))) |
| typebits.Set(t, 0, vec) |
| |
| nptr := types.PtrDataSize(t) / int64(types.PtrSize) |
| for i := int64(0); i < nptr; i++ { |
| if vec.Get(int32(i)) { |
| ptrmask[i/8] |= 1 << (uint(i) % 8) |
| } |
| } |
| } |
| |
| // dgcprog emits and returns the symbol containing a GC program for type t |
| // along with the size of the data described by the program (in the range |
| // [types.PtrDataSize(t), t.Width]). |
| // In practice, the size is types.PtrDataSize(t) except for non-trivial arrays. |
| // For non-trivial arrays, the program describes the full t.Width size. |
| func dgcprog(t *types.Type, write bool) (*obj.LSym, int64) { |
| types.CalcSize(t) |
| if t.Width == types.BADWIDTH { |
| base.Fatalf("dgcprog: %v badwidth", t) |
| } |
| lsym := TypeLinksymPrefix(".gcprog", t) |
| var p gcProg |
| p.init(lsym, write) |
| p.emit(t, 0) |
| offset := p.w.BitIndex() * int64(types.PtrSize) |
| p.end() |
| if ptrdata := types.PtrDataSize(t); offset < ptrdata || offset > t.Width { |
| base.Fatalf("dgcprog: %v: offset=%d but ptrdata=%d size=%d", t, offset, ptrdata, t.Width) |
| } |
| return lsym, offset |
| } |
| |
| type gcProg struct { |
| lsym *obj.LSym |
| symoff int |
| w gcprog.Writer |
| write bool |
| } |
| |
| func (p *gcProg) init(lsym *obj.LSym, write bool) { |
| p.lsym = lsym |
| p.write = write && !lsym.OnList() |
| p.symoff = 4 // first 4 bytes hold program length |
| if !write { |
| p.w.Init(func(byte) {}) |
| return |
| } |
| p.w.Init(p.writeByte) |
| if base.Debug.GCProg > 0 { |
| fmt.Fprintf(os.Stderr, "compile: start GCProg for %v\n", lsym) |
| p.w.Debug(os.Stderr) |
| } |
| } |
| |
| func (p *gcProg) writeByte(x byte) { |
| p.symoff = objw.Uint8(p.lsym, p.symoff, x) |
| } |
| |
| func (p *gcProg) end() { |
| p.w.End() |
| if !p.write { |
| return |
| } |
| objw.Uint32(p.lsym, 0, uint32(p.symoff-4)) |
| objw.Global(p.lsym, int32(p.symoff), obj.DUPOK|obj.RODATA|obj.LOCAL) |
| p.lsym.Set(obj.AttrContentAddressable, true) |
| if base.Debug.GCProg > 0 { |
| fmt.Fprintf(os.Stderr, "compile: end GCProg for %v\n", p.lsym) |
| } |
| } |
| |
| func (p *gcProg) emit(t *types.Type, offset int64) { |
| types.CalcSize(t) |
| if !t.HasPointers() { |
| return |
| } |
| if t.Width == int64(types.PtrSize) { |
| p.w.Ptr(offset / int64(types.PtrSize)) |
| return |
| } |
| switch t.Kind() { |
| default: |
| base.Fatalf("gcProg.emit: unexpected type %v", t) |
| |
| case types.TSTRING: |
| p.w.Ptr(offset / int64(types.PtrSize)) |
| |
| case types.TINTER: |
| // Note: the first word isn't a pointer. See comment in typebits.Set |
| p.w.Ptr(offset/int64(types.PtrSize) + 1) |
| |
| case types.TSLICE: |
| p.w.Ptr(offset / int64(types.PtrSize)) |
| |
| case types.TARRAY: |
| if t.NumElem() == 0 { |
| // should have been handled by haspointers check above |
| base.Fatalf("gcProg.emit: empty array") |
| } |
| |
| // Flatten array-of-array-of-array to just a big array by multiplying counts. |
| count := t.NumElem() |
| elem := t.Elem() |
| for elem.IsArray() { |
| count *= elem.NumElem() |
| elem = elem.Elem() |
| } |
| |
| if !p.w.ShouldRepeat(elem.Width/int64(types.PtrSize), count) { |
| // Cheaper to just emit the bits. |
| for i := int64(0); i < count; i++ { |
| p.emit(elem, offset+i*elem.Width) |
| } |
| return |
| } |
| p.emit(elem, offset) |
| p.w.ZeroUntil((offset + elem.Width) / int64(types.PtrSize)) |
| p.w.Repeat(elem.Width/int64(types.PtrSize), count-1) |
| |
| case types.TSTRUCT: |
| for _, t1 := range t.Fields().Slice() { |
| p.emit(t1.Type, offset+t1.Offset) |
| } |
| } |
| } |
| |
| // ZeroAddr returns the address of a symbol with at least |
| // size bytes of zeros. |
| func ZeroAddr(size int64) ir.Node { |
| if size >= 1<<31 { |
| base.Fatalf("map elem too big %d", size) |
| } |
| if ZeroSize < size { |
| ZeroSize = size |
| } |
| lsym := base.PkgLinksym("go.map", "zero", obj.ABI0) |
| x := ir.NewLinksymExpr(base.Pos, lsym, types.Types[types.TUINT8]) |
| return typecheck.Expr(typecheck.NodAddr(x)) |
| } |
| |
| func CollectPTabs() { |
| if !base.Ctxt.Flag_dynlink || types.LocalPkg.Name != "main" { |
| return |
| } |
| for _, exportn := range typecheck.Target.Exports { |
| s := exportn.Sym() |
| nn := ir.AsNode(s.Def) |
| if nn == nil { |
| continue |
| } |
| if nn.Op() != ir.ONAME { |
| continue |
| } |
| n := nn.(*ir.Name) |
| if !types.IsExported(s.Name) { |
| continue |
| } |
| if s.Pkg.Name != "main" { |
| continue |
| } |
| ptabs = append(ptabs, n) |
| } |
| } |
| |
| // Generate a wrapper function to convert from |
| // a receiver of type T to a receiver of type U. |
| // That is, |
| // |
| // func (t T) M() { |
| // ... |
| // } |
| // |
| // already exists; this function generates |
| // |
| // func (u U) M() { |
| // u.M() |
| // } |
| // |
| // where the types T and U are such that u.M() is valid |
| // and calls the T.M method. |
| // The resulting function is for use in method tables. |
| // |
| // rcvr - U |
| // method - M func (t T)(), a TFIELD type struct |
| func methodWrapper(rcvr *types.Type, method *types.Field) *obj.LSym { |
| newnam := ir.MethodSym(rcvr, method.Sym) |
| lsym := newnam.Linksym() |
| if newnam.Siggen() { |
| return lsym |
| } |
| newnam.SetSiggen(true) |
| |
| if types.Identical(rcvr, method.Type.Recv().Type) { |
| return lsym |
| } |
| |
| // Only generate (*T).M wrappers for T.M in T's own package. |
| if rcvr.IsPtr() && rcvr.Elem() == method.Type.Recv().Type && |
| rcvr.Elem().Sym() != nil && rcvr.Elem().Sym().Pkg != types.LocalPkg { |
| return lsym |
| } |
| |
| // Only generate I.M wrappers for I in I's own package |
| // but keep doing it for error.Error (was issue #29304). |
| if rcvr.IsInterface() && rcvr.Sym() != nil && rcvr.Sym().Pkg != types.LocalPkg && rcvr != types.ErrorType { |
| return lsym |
| } |
| |
| base.Pos = base.AutogeneratedPos |
| typecheck.DeclContext = ir.PEXTERN |
| |
| tfn := ir.NewFuncType(base.Pos, |
| ir.NewField(base.Pos, typecheck.Lookup(".this"), nil, rcvr), |
| typecheck.NewFuncParams(method.Type.Params(), true), |
| typecheck.NewFuncParams(method.Type.Results(), false)) |
| |
| // TODO(austin): SelectorExpr may have created one or more |
| // ir.Names for these already with a nil Func field. We should |
| // consolidate these and always attach a Func to the Name. |
| fn := typecheck.DeclFunc(newnam, tfn) |
| fn.SetDupok(true) |
| |
| nthis := ir.AsNode(tfn.Type().Recv().Nname) |
| |
| methodrcvr := method.Type.Recv().Type |
| |
| // generate nil pointer check for better error |
| if rcvr.IsPtr() && rcvr.Elem() == methodrcvr { |
| // generating wrapper from *T to T. |
| n := ir.NewIfStmt(base.Pos, nil, nil, nil) |
| n.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, nthis, typecheck.NodNil()) |
| call := ir.NewCallExpr(base.Pos, ir.OCALL, typecheck.LookupRuntime("panicwrap"), nil) |
| n.Body = []ir.Node{call} |
| fn.Body.Append(n) |
| } |
| |
| dot := typecheck.AddImplicitDots(ir.NewSelectorExpr(base.Pos, ir.OXDOT, nthis, method.Sym)) |
| |
| // generate call |
| // It's not possible to use a tail call when dynamic linking on ppc64le. The |
| // bad scenario is when a local call is made to the wrapper: the wrapper will |
| // call the implementation, which might be in a different module and so set |
| // the TOC to the appropriate value for that module. But if it returns |
| // directly to the wrapper's caller, nothing will reset it to the correct |
| // value for that function. |
| // |
| // Disable tailcall for RegabiArgs for now. The IR does not connect the |
| // arguments with the OTAILCALL node, and the arguments are not marshaled |
| // correctly. |
| if !base.Flag.Cfg.Instrumenting && rcvr.IsPtr() && methodrcvr.IsPtr() && method.Embedded != 0 && !types.IsInterfaceMethod(method.Type) && !(base.Ctxt.Arch.Name == "ppc64le" && base.Ctxt.Flag_dynlink) && !buildcfg.Experiment.RegabiArgs { |
| // generate tail call: adjust pointer receiver and jump to embedded method. |
| left := dot.X // skip final .M |
| if !left.Type().IsPtr() { |
| left = typecheck.NodAddr(left) |
| } |
| as := ir.NewAssignStmt(base.Pos, nthis, typecheck.ConvNop(left, rcvr)) |
| fn.Body.Append(as) |
| fn.Body.Append(ir.NewTailCallStmt(base.Pos, method.Nname.(*ir.Name))) |
| } else { |
| fn.SetWrapper(true) // ignore frame for panic+recover matching |
| call := ir.NewCallExpr(base.Pos, ir.OCALL, dot, nil) |
| call.Args = ir.ParamNames(tfn.Type()) |
| call.IsDDD = tfn.Type().IsVariadic() |
| if method.Type.NumResults() > 0 { |
| ret := ir.NewReturnStmt(base.Pos, nil) |
| ret.Results = []ir.Node{call} |
| fn.Body.Append(ret) |
| } else { |
| fn.Body.Append(call) |
| } |
| } |
| |
| typecheck.FinishFuncBody() |
| if base.Debug.DclStack != 0 { |
| types.CheckDclstack() |
| } |
| |
| typecheck.Func(fn) |
| ir.CurFunc = fn |
| typecheck.Stmts(fn.Body) |
| |
| // Inline calls within (*T).M wrappers. This is safe because we only |
| // generate those wrappers within the same compilation unit as (T).M. |
| // TODO(mdempsky): Investigate why we can't enable this more generally. |
| if rcvr.IsPtr() && rcvr.Elem() == method.Type.Recv().Type && rcvr.Elem().Sym() != nil { |
| inline.InlineCalls(fn) |
| } |
| escape.Batch([]*ir.Func{fn}, false) |
| |
| ir.CurFunc = nil |
| typecheck.Target.Decls = append(typecheck.Target.Decls, fn) |
| |
| return lsym |
| } |
| |
| var ZeroSize int64 |
| |
| // MarkTypeUsedInInterface marks that type t is converted to an interface. |
| // This information is used in the linker in dead method elimination. |
| func MarkTypeUsedInInterface(t *types.Type, from *obj.LSym) { |
| tsym := TypeLinksym(t) |
| // Emit a marker relocation. The linker will know the type is converted |
| // to an interface if "from" is reachable. |
| r := obj.Addrel(from) |
| r.Sym = tsym |
| r.Type = objabi.R_USEIFACE |
| } |
| |
| // MarkUsedIfaceMethod marks that an interface method is used in the current |
| // function. n is OCALLINTER node. |
| func MarkUsedIfaceMethod(n *ir.CallExpr) { |
| // skip unnamed functions (func _()) |
| if ir.CurFunc.LSym == nil { |
| return |
| } |
| dot := n.X.(*ir.SelectorExpr) |
| ityp := dot.X.Type() |
| tsym := TypeLinksym(ityp) |
| r := obj.Addrel(ir.CurFunc.LSym) |
| r.Sym = tsym |
| // dot.Xoffset is the method index * PtrSize (the offset of code pointer |
| // in itab). |
| midx := dot.Offset() / int64(types.PtrSize) |
| r.Add = InterfaceMethodOffset(ityp, midx) |
| r.Type = objabi.R_USEIFACEMETHOD |
| } |