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// Copyright 2017 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 types
import (
"cmd/internal/obj"
"cmd/internal/src"
"fmt"
)
// Dummy Node so we can refer to *Node without actually
// having a gc.Node. Necessary to break import cycles.
// TODO(gri) try to eliminate soon
type Node struct{ _ int }
//go:generate stringer -type EType -trimprefix T
// EType describes a kind of type.
type EType uint8
const (
Txxx EType = iota
TINT8
TUINT8
TINT16
TUINT16
TINT32
TUINT32
TINT64
TUINT64
TINT
TUINT
TUINTPTR
TCOMPLEX64
TCOMPLEX128
TFLOAT32
TFLOAT64
TBOOL
TPTR
TFUNC
TSLICE
TARRAY
TSTRUCT
TCHAN
TMAP
TINTER
TFORW
TANY
TSTRING
TUNSAFEPTR
// pseudo-types for literals
TIDEAL
TNIL
TBLANK
// pseudo-types for frame layout
TFUNCARGS
TCHANARGS
// pseudo-types for import/export
TDDDFIELD // wrapper: contained type is a ... field
// SSA backend types
TSSA // internal types used by SSA backend (flags, memory, etc.)
TTUPLE // a pair of types, used by SSA backend
NTYPE
)
// ChanDir is whether a channel can send, receive, or both.
type ChanDir uint8
func (c ChanDir) CanRecv() bool { return c&Crecv != 0 }
func (c ChanDir) CanSend() bool { return c&Csend != 0 }
const (
// types of channel
// must match ../../../../reflect/type.go:/ChanDir
Crecv ChanDir = 1 << 0
Csend ChanDir = 1 << 1
Cboth ChanDir = Crecv | Csend
)
// Types stores pointers to predeclared named types.
//
// It also stores pointers to several special types:
// - Types[TANY] is the placeholder "any" type recognized by substArgTypes.
// - Types[TBLANK] represents the blank variable's type.
// - Types[TIDEAL] represents untyped numeric constants.
// - Types[TNIL] represents the predeclared "nil" value's type.
// - Types[TUNSAFEPTR] is package unsafe's Pointer type.
var Types [NTYPE]*Type
var (
// Predeclared alias types. Kept separate for better error messages.
Bytetype *Type
Runetype *Type
// Predeclared error interface type.
Errortype *Type
// Types to represent untyped string and boolean constants.
Idealstring *Type
Idealbool *Type
// Types to represent untyped numeric constants.
// Note: Currently these are only used within the binary export
// data format. The rest of the compiler only uses Types[TIDEAL].
Idealint = New(TIDEAL)
Idealrune = New(TIDEAL)
Idealfloat = New(TIDEAL)
Idealcomplex = New(TIDEAL)
)
// A Type represents a Go type.
type Type struct {
// Extra contains extra etype-specific fields.
// As an optimization, those etype-specific structs which contain exactly
// one pointer-shaped field are stored as values rather than pointers when possible.
//
// TMAP: *Map
// TFORW: *Forward
// TFUNC: *Func
// TSTRUCT: *Struct
// TINTER: *Interface
// TDDDFIELD: DDDField
// TFUNCARGS: FuncArgs
// TCHANARGS: ChanArgs
// TCHAN: *Chan
// TPTR: Ptr
// TARRAY: *Array
// TSLICE: Slice
Extra interface{}
// Width is the width of this Type in bytes.
Width int64 // valid if Align > 0
methods Fields
allMethods Fields
Nod *Node // canonical OTYPE node
Orig *Type // original type (type literal or predefined type)
// Cache of composite types, with this type being the element type.
Cache struct {
ptr *Type // *T, or nil
slice *Type // []T, or nil
}
Sym *Sym // symbol containing name, for named types
Vargen int32 // unique name for OTYPE/ONAME
Etype EType // kind of type
Align uint8 // the required alignment of this type, in bytes (0 means Width and Align have not yet been computed)
flags bitset8
}
const (
typeNotInHeap = 1 << iota // type cannot be heap allocated
typeBroke // broken type definition
typeNoalg // suppress hash and eq algorithm generation
typeDeferwidth // width computation has been deferred and type is on deferredTypeStack
typeRecur
)
func (t *Type) NotInHeap() bool { return t.flags&typeNotInHeap != 0 }
func (t *Type) Broke() bool { return t.flags&typeBroke != 0 }
func (t *Type) Noalg() bool { return t.flags&typeNoalg != 0 }
func (t *Type) Deferwidth() bool { return t.flags&typeDeferwidth != 0 }
func (t *Type) Recur() bool { return t.flags&typeRecur != 0 }
func (t *Type) SetNotInHeap(b bool) { t.flags.set(typeNotInHeap, b) }
func (t *Type) SetBroke(b bool) { t.flags.set(typeBroke, b) }
func (t *Type) SetNoalg(b bool) { t.flags.set(typeNoalg, b) }
func (t *Type) SetDeferwidth(b bool) { t.flags.set(typeDeferwidth, b) }
func (t *Type) SetRecur(b bool) { t.flags.set(typeRecur, b) }
// Pkg returns the package that t appeared in.
//
// Pkg is only defined for function, struct, and interface types
// (i.e., types with named elements). This information isn't used by
// cmd/compile itself, but we need to track it because it's exposed by
// the go/types API.
func (t *Type) Pkg() *Pkg {
switch t.Etype {
case TFUNC:
return t.Extra.(*Func).pkg
case TSTRUCT:
return t.Extra.(*Struct).pkg
case TINTER:
return t.Extra.(*Interface).pkg
default:
Fatalf("Pkg: unexpected kind: %v", t)
return nil
}
}
// SetPkg sets the package that t appeared in.
func (t *Type) SetPkg(pkg *Pkg) {
switch t.Etype {
case TFUNC:
t.Extra.(*Func).pkg = pkg
case TSTRUCT:
t.Extra.(*Struct).pkg = pkg
case TINTER:
t.Extra.(*Interface).pkg = pkg
default:
Fatalf("Pkg: unexpected kind: %v", t)
}
}
// Map contains Type fields specific to maps.
type Map struct {
Key *Type // Key type
Elem *Type // Val (elem) type
Bucket *Type // internal struct type representing a hash bucket
Hmap *Type // internal struct type representing the Hmap (map header object)
Hiter *Type // internal struct type representing hash iterator state
}
// MapType returns t's extra map-specific fields.
func (t *Type) MapType() *Map {
t.wantEtype(TMAP)
return t.Extra.(*Map)
}
// Forward contains Type fields specific to forward types.
type Forward struct {
Copyto []*Node // where to copy the eventual value to
Embedlineno src.XPos // first use of this type as an embedded type
}
// ForwardType returns t's extra forward-type-specific fields.
func (t *Type) ForwardType() *Forward {
t.wantEtype(TFORW)
return t.Extra.(*Forward)
}
// Func contains Type fields specific to func types.
type Func struct {
Receiver *Type // function receiver
Results *Type // function results
Params *Type // function params
Nname *Node
pkg *Pkg
// Argwid is the total width of the function receiver, params, and results.
// It gets calculated via a temporary TFUNCARGS type.
// Note that TFUNC's Width is Widthptr.
Argwid int64
Outnamed bool
}
// FuncType returns t's extra func-specific fields.
func (t *Type) FuncType() *Func {
t.wantEtype(TFUNC)
return t.Extra.(*Func)
}
// StructType contains Type fields specific to struct types.
type Struct struct {
fields Fields
pkg *Pkg
// Maps have three associated internal structs (see struct MapType).
// Map links such structs back to their map type.
Map *Type
Funarg Funarg // type of function arguments for arg struct
}
// Fnstruct records the kind of function argument
type Funarg uint8
const (
FunargNone Funarg = iota
FunargRcvr // receiver
FunargParams // input parameters
FunargResults // output results
)
// StructType returns t's extra struct-specific fields.
func (t *Type) StructType() *Struct {
t.wantEtype(TSTRUCT)
return t.Extra.(*Struct)
}
// Interface contains Type fields specific to interface types.
type Interface struct {
Fields Fields
pkg *Pkg
}
// Ptr contains Type fields specific to pointer types.
type Ptr struct {
Elem *Type // element type
}
// DDDField contains Type fields specific to TDDDFIELD types.
type DDDField struct {
T *Type // reference to a slice type for ... args
}
// ChanArgs contains Type fields specific to TCHANARGS types.
type ChanArgs struct {
T *Type // reference to a chan type whose elements need a width check
}
// // FuncArgs contains Type fields specific to TFUNCARGS types.
type FuncArgs struct {
T *Type // reference to a func type whose elements need a width check
}
// Chan contains Type fields specific to channel types.
type Chan struct {
Elem *Type // element type
Dir ChanDir // channel direction
}
// ChanType returns t's extra channel-specific fields.
func (t *Type) ChanType() *Chan {
t.wantEtype(TCHAN)
return t.Extra.(*Chan)
}
type Tuple struct {
first *Type
second *Type
// Any tuple with a memory type must put that memory type second.
}
// Array contains Type fields specific to array types.
type Array struct {
Elem *Type // element type
Bound int64 // number of elements; <0 if unknown yet
}
// Slice contains Type fields specific to slice types.
type Slice struct {
Elem *Type // element type
}
// A Field represents a field in a struct or a method in an interface or
// associated with a named type.
type Field struct {
flags bitset8
Embedded uint8 // embedded field
Pos src.XPos
Sym *Sym
Type *Type // field type
Note string // literal string annotation
// For fields that represent function parameters, Nname points
// to the associated ONAME Node.
Nname *Node
// Offset in bytes of this field or method within its enclosing struct
// or interface Type.
Offset int64
}
const (
fieldIsDDD = 1 << iota // field is ... argument
fieldBroke // broken field definition
fieldNointerface
)
func (f *Field) IsDDD() bool { return f.flags&fieldIsDDD != 0 }
func (f *Field) Broke() bool { return f.flags&fieldBroke != 0 }
func (f *Field) Nointerface() bool { return f.flags&fieldNointerface != 0 }
func (f *Field) SetIsDDD(b bool) { f.flags.set(fieldIsDDD, b) }
func (f *Field) SetBroke(b bool) { f.flags.set(fieldBroke, b) }
func (f *Field) SetNointerface(b bool) { f.flags.set(fieldNointerface, b) }
// End returns the offset of the first byte immediately after this field.
func (f *Field) End() int64 {
return f.Offset + f.Type.Width
}
// Fields is a pointer to a slice of *Field.
// This saves space in Types that do not have fields or methods
// compared to a simple slice of *Field.
type Fields struct {
s *[]*Field
}
// Len returns the number of entries in f.
func (f *Fields) Len() int {
if f.s == nil {
return 0
}
return len(*f.s)
}
// Slice returns the entries in f as a slice.
// Changes to the slice entries will be reflected in f.
func (f *Fields) Slice() []*Field {
if f.s == nil {
return nil
}
return *f.s
}
// Index returns the i'th element of Fields.
// It panics if f does not have at least i+1 elements.
func (f *Fields) Index(i int) *Field {
return (*f.s)[i]
}
// Set sets f to a slice.
// This takes ownership of the slice.
func (f *Fields) Set(s []*Field) {
if len(s) == 0 {
f.s = nil
} else {
// Copy s and take address of t rather than s to avoid
// allocation in the case where len(s) == 0.
t := s
f.s = &t
}
}
// Append appends entries to f.
func (f *Fields) Append(s ...*Field) {
if f.s == nil {
f.s = new([]*Field)
}
*f.s = append(*f.s, s...)
}
// New returns a new Type of the specified kind.
func New(et EType) *Type {
t := &Type{
Etype: et,
Width: BADWIDTH,
}
t.Orig = t
// TODO(josharian): lazily initialize some of these?
switch t.Etype {
case TMAP:
t.Extra = new(Map)
case TFORW:
t.Extra = new(Forward)
case TFUNC:
t.Extra = new(Func)
case TSTRUCT:
t.Extra = new(Struct)
case TINTER:
t.Extra = new(Interface)
case TPTR:
t.Extra = Ptr{}
case TCHANARGS:
t.Extra = ChanArgs{}
case TFUNCARGS:
t.Extra = FuncArgs{}
case TDDDFIELD:
t.Extra = DDDField{}
case TCHAN:
t.Extra = new(Chan)
case TTUPLE:
t.Extra = new(Tuple)
}
return t
}
// NewArray returns a new fixed-length array Type.
func NewArray(elem *Type, bound int64) *Type {
if bound < 0 {
Fatalf("NewArray: invalid bound %v", bound)
}
t := New(TARRAY)
t.Extra = &Array{Elem: elem, Bound: bound}
t.SetNotInHeap(elem.NotInHeap())
return t
}
// NewSlice returns the slice Type with element type elem.
func NewSlice(elem *Type) *Type {
if t := elem.Cache.slice; t != nil {
if t.Elem() != elem {
Fatalf("elem mismatch")
}
return t
}
t := New(TSLICE)
t.Extra = Slice{Elem: elem}
elem.Cache.slice = t
return t
}
// NewDDDArray returns a new [...]T array Type.
func NewDDDArray(elem *Type) *Type {
t := New(TARRAY)
t.Extra = &Array{Elem: elem, Bound: -1}
t.SetNotInHeap(elem.NotInHeap())
return t
}
// NewChan returns a new chan Type with direction dir.
func NewChan(elem *Type, dir ChanDir) *Type {
t := New(TCHAN)
ct := t.ChanType()
ct.Elem = elem
ct.Dir = dir
return t
}
func NewTuple(t1, t2 *Type) *Type {
t := New(TTUPLE)
t.Extra.(*Tuple).first = t1
t.Extra.(*Tuple).second = t2
return t
}
func newSSA(name string) *Type {
t := New(TSSA)
t.Extra = name
return t
}
// NewMap returns a new map Type with key type k and element (aka value) type v.
func NewMap(k, v *Type) *Type {
t := New(TMAP)
mt := t.MapType()
mt.Key = k
mt.Elem = v
return t
}
// NewPtrCacheEnabled controls whether *T Types are cached in T.
// Caching is disabled just before starting the backend.
// This allows the backend to run concurrently.
var NewPtrCacheEnabled = true
// NewPtr returns the pointer type pointing to t.
func NewPtr(elem *Type) *Type {
if elem == nil {
Fatalf("NewPtr: pointer to elem Type is nil")
}
if t := elem.Cache.ptr; t != nil {
if t.Elem() != elem {
Fatalf("NewPtr: elem mismatch")
}
return t
}
t := New(TPTR)
t.Extra = Ptr{Elem: elem}
t.Width = int64(Widthptr)
t.Align = uint8(Widthptr)
if NewPtrCacheEnabled {
elem.Cache.ptr = t
}
return t
}
// NewDDDField returns a new TDDDFIELD type for slice type s.
func NewDDDField(s *Type) *Type {
t := New(TDDDFIELD)
t.Extra = DDDField{T: s}
return t
}
// NewChanArgs returns a new TCHANARGS type for channel type c.
func NewChanArgs(c *Type) *Type {
t := New(TCHANARGS)
t.Extra = ChanArgs{T: c}
return t
}
// NewFuncArgs returns a new TFUNCARGS type for func type f.
func NewFuncArgs(f *Type) *Type {
t := New(TFUNCARGS)
t.Extra = FuncArgs{T: f}
return t
}
func NewField() *Field {
return &Field{
Offset: BADWIDTH,
}
}
// SubstAny walks t, replacing instances of "any" with successive
// elements removed from types. It returns the substituted type.
func SubstAny(t *Type, types *[]*Type) *Type {
if t == nil {
return nil
}
switch t.Etype {
default:
// Leave the type unchanged.
case TANY:
if len(*types) == 0 {
Fatalf("substArgTypes: not enough argument types")
}
t = (*types)[0]
*types = (*types)[1:]
case TPTR:
elem := SubstAny(t.Elem(), types)
if elem != t.Elem() {
t = t.copy()
t.Extra = Ptr{Elem: elem}
}
case TARRAY:
elem := SubstAny(t.Elem(), types)
if elem != t.Elem() {
t = t.copy()
t.Extra.(*Array).Elem = elem
}
case TSLICE:
elem := SubstAny(t.Elem(), types)
if elem != t.Elem() {
t = t.copy()
t.Extra = Slice{Elem: elem}
}
case TCHAN:
elem := SubstAny(t.Elem(), types)
if elem != t.Elem() {
t = t.copy()
t.Extra.(*Chan).Elem = elem
}
case TMAP:
key := SubstAny(t.Key(), types)
elem := SubstAny(t.Elem(), types)
if key != t.Key() || elem != t.Elem() {
t = t.copy()
t.Extra.(*Map).Key = key
t.Extra.(*Map).Elem = elem
}
case TFUNC:
recvs := SubstAny(t.Recvs(), types)
params := SubstAny(t.Params(), types)
results := SubstAny(t.Results(), types)
if recvs != t.Recvs() || params != t.Params() || results != t.Results() {
t = t.copy()
t.FuncType().Receiver = recvs
t.FuncType().Results = results
t.FuncType().Params = params
}
case TSTRUCT:
// Make a copy of all fields, including ones whose type does not change.
// This prevents aliasing across functions, which can lead to later
// fields getting their Offset incorrectly overwritten.
fields := t.FieldSlice()
nfs := make([]*Field, len(fields))
for i, f := range fields {
nft := SubstAny(f.Type, types)
nfs[i] = f.Copy()
nfs[i].Type = nft
}
t = t.copy()
t.SetFields(nfs)
}
return t
}
// copy returns a shallow copy of the Type.
func (t *Type) copy() *Type {
if t == nil {
return nil
}
nt := *t
// copy any *T Extra fields, to avoid aliasing
switch t.Etype {
case TMAP:
x := *t.Extra.(*Map)
nt.Extra = &x
case TFORW:
x := *t.Extra.(*Forward)
nt.Extra = &x
case TFUNC:
x := *t.Extra.(*Func)
nt.Extra = &x
case TSTRUCT:
x := *t.Extra.(*Struct)
nt.Extra = &x
case TINTER:
x := *t.Extra.(*Interface)
nt.Extra = &x
case TCHAN:
x := *t.Extra.(*Chan)
nt.Extra = &x
case TARRAY:
x := *t.Extra.(*Array)
nt.Extra = &x
case TTUPLE, TSSA:
Fatalf("ssa types cannot be copied")
}
// TODO(mdempsky): Find out why this is necessary and explain.
if t.Orig == t {
nt.Orig = &nt
}
return &nt
}
func (f *Field) Copy() *Field {
nf := *f
return &nf
}
func (t *Type) wantEtype(et EType) {
if t.Etype != et {
Fatalf("want %v, but have %v", et, t)
}
}
func (t *Type) Recvs() *Type { return t.FuncType().Receiver }
func (t *Type) Params() *Type { return t.FuncType().Params }
func (t *Type) Results() *Type { return t.FuncType().Results }
func (t *Type) NumRecvs() int { return t.FuncType().Receiver.NumFields() }
func (t *Type) NumParams() int { return t.FuncType().Params.NumFields() }
func (t *Type) NumResults() int { return t.FuncType().Results.NumFields() }
// IsVariadic reports whether function type t is variadic.
func (t *Type) IsVariadic() bool {
n := t.NumParams()
return n > 0 && t.Params().Field(n-1).IsDDD()
}
// Recv returns the receiver of function type t, if any.
func (t *Type) Recv() *Field {
s := t.Recvs()
if s.NumFields() == 0 {
return nil
}
return s.Field(0)
}
// RecvsParamsResults stores the accessor functions for a function Type's
// receiver, parameters, and result parameters, in that order.
// It can be used to iterate over all of a function's parameter lists.
var RecvsParamsResults = [3]func(*Type) *Type{
(*Type).Recvs, (*Type).Params, (*Type).Results,
}
// RecvsParams is like RecvsParamsResults, but omits result parameters.
var RecvsParams = [2]func(*Type) *Type{
(*Type).Recvs, (*Type).Params,
}
// ParamsResults is like RecvsParamsResults, but omits receiver parameters.
var ParamsResults = [2]func(*Type) *Type{
(*Type).Params, (*Type).Results,
}
// Key returns the key type of map type t.
func (t *Type) Key() *Type {
t.wantEtype(TMAP)
return t.Extra.(*Map).Key
}
// Elem returns the type of elements of t.
// Usable with pointers, channels, arrays, slices, and maps.
func (t *Type) Elem() *Type {
switch t.Etype {
case TPTR:
return t.Extra.(Ptr).Elem
case TARRAY:
return t.Extra.(*Array).Elem
case TSLICE:
return t.Extra.(Slice).Elem
case TCHAN:
return t.Extra.(*Chan).Elem
case TMAP:
return t.Extra.(*Map).Elem
}
Fatalf("Type.Elem %s", t.Etype)
return nil
}
// DDDField returns the slice ... type for TDDDFIELD type t.
func (t *Type) DDDField() *Type {
t.wantEtype(TDDDFIELD)
return t.Extra.(DDDField).T
}
// ChanArgs returns the channel type for TCHANARGS type t.
func (t *Type) ChanArgs() *Type {
t.wantEtype(TCHANARGS)
return t.Extra.(ChanArgs).T
}
// FuncArgs returns the func type for TFUNCARGS type t.
func (t *Type) FuncArgs() *Type {
t.wantEtype(TFUNCARGS)
return t.Extra.(FuncArgs).T
}
// Nname returns the associated function's nname.
func (t *Type) Nname() *Node {
switch t.Etype {
case TFUNC:
return t.Extra.(*Func).Nname
}
Fatalf("Type.Nname %v %v", t.Etype, t)
return nil
}
// Nname sets the associated function's nname.
func (t *Type) SetNname(n *Node) {
switch t.Etype {
case TFUNC:
t.Extra.(*Func).Nname = n
default:
Fatalf("Type.SetNname %v %v", t.Etype, t)
}
}
// IsFuncArgStruct reports whether t is a struct representing function parameters.
func (t *Type) IsFuncArgStruct() bool {
return t.Etype == TSTRUCT && t.Extra.(*Struct).Funarg != FunargNone
}
func (t *Type) Methods() *Fields {
// TODO(mdempsky): Validate t?
return &t.methods
}
func (t *Type) AllMethods() *Fields {
// TODO(mdempsky): Validate t?
return &t.allMethods
}
func (t *Type) Fields() *Fields {
switch t.Etype {
case TSTRUCT:
return &t.Extra.(*Struct).fields
case TINTER:
Dowidth(t)
return &t.Extra.(*Interface).Fields
}
Fatalf("Fields: type %v does not have fields", t)
return nil
}
// Field returns the i'th field/method of struct/interface type t.
func (t *Type) Field(i int) *Field {
return t.Fields().Slice()[i]
}
// FieldSlice returns a slice of containing all fields/methods of
// struct/interface type t.
func (t *Type) FieldSlice() []*Field {
return t.Fields().Slice()
}
// SetFields sets struct/interface type t's fields/methods to fields.
func (t *Type) SetFields(fields []*Field) {
// If we've calculated the width of t before,
// then some other type such as a function signature
// might now have the wrong type.
// Rather than try to track and invalidate those,
// enforce that SetFields cannot be called once
// t's width has been calculated.
if t.WidthCalculated() {
Fatalf("SetFields of %v: width previously calculated", t)
}
t.wantEtype(TSTRUCT)
for _, f := range fields {
// If type T contains a field F with a go:notinheap
// type, then T must also be go:notinheap. Otherwise,
// you could heap allocate T and then get a pointer F,
// which would be a heap pointer to a go:notinheap
// type.
if f.Type != nil && f.Type.NotInHeap() {
t.SetNotInHeap(true)
break
}
}
t.Fields().Set(fields)
}
func (t *Type) SetInterface(methods []*Field) {
t.wantEtype(TINTER)
t.Methods().Set(methods)
}
func (t *Type) IsDDDArray() bool {
if t.Etype != TARRAY {
return false
}
return t.Extra.(*Array).Bound < 0
}
func (t *Type) WidthCalculated() bool {
return t.Align > 0
}
// ArgWidth returns the total aligned argument size for a function.
// It includes the receiver, parameters, and results.
func (t *Type) ArgWidth() int64 {
t.wantEtype(TFUNC)
return t.Extra.(*Func).Argwid
}
func (t *Type) Size() int64 {
if t.Etype == TSSA {
if t == TypeInt128 {
return 16
}
return 0
}
Dowidth(t)
return t.Width
}
func (t *Type) Alignment() int64 {
Dowidth(t)
return int64(t.Align)
}
func (t *Type) SimpleString() string {
return t.Etype.String()
}
// Cmp is a comparison between values a and b.
// -1 if a < b
// 0 if a == b
// 1 if a > b
type Cmp int8
const (
CMPlt = Cmp(-1)
CMPeq = Cmp(0)
CMPgt = Cmp(1)
)
// Compare compares types for purposes of the SSA back
// end, returning a Cmp (one of CMPlt, CMPeq, CMPgt).
// The answers are correct for an optimizer
// or code generator, but not necessarily typechecking.
// The order chosen is arbitrary, only consistency and division
// into equivalence classes (Types that compare CMPeq) matters.
func (t *Type) Compare(x *Type) Cmp {
if x == t {
return CMPeq
}
return t.cmp(x)
}
func cmpForNe(x bool) Cmp {
if x {
return CMPlt
}
return CMPgt
}
func (r *Sym) cmpsym(s *Sym) Cmp {
if r == s {
return CMPeq
}
if r == nil {
return CMPlt
}
if s == nil {
return CMPgt
}
// Fast sort, not pretty sort
if len(r.Name) != len(s.Name) {
return cmpForNe(len(r.Name) < len(s.Name))
}
if r.Pkg != s.Pkg {
if len(r.Pkg.Prefix) != len(s.Pkg.Prefix) {
return cmpForNe(len(r.Pkg.Prefix) < len(s.Pkg.Prefix))
}
if r.Pkg.Prefix != s.Pkg.Prefix {
return cmpForNe(r.Pkg.Prefix < s.Pkg.Prefix)
}
}
if r.Name != s.Name {
return cmpForNe(r.Name < s.Name)
}
return CMPeq
}
// cmp compares two *Types t and x, returning CMPlt,
// CMPeq, CMPgt as t<x, t==x, t>x, for an arbitrary
// and optimizer-centric notion of comparison.
// TODO(josharian): make this safe for recursive interface types
// and use in signatlist sorting. See issue 19869.
func (t *Type) cmp(x *Type) Cmp {
// This follows the structure of eqtype in subr.go
// with two exceptions.
// 1. Symbols are compared more carefully because a <,=,> result is desired.
// 2. Maps are treated specially to avoid endless recursion -- maps
// contain an internal data type not expressible in Go source code.
if t == x {
return CMPeq
}
if t == nil {
return CMPlt
}
if x == nil {
return CMPgt
}
if t.Etype != x.Etype {
return cmpForNe(t.Etype < x.Etype)
}
if t.Sym != nil || x.Sym != nil {
// Special case: we keep byte and uint8 separate
// for error messages. Treat them as equal.
switch t.Etype {
case TUINT8:
if (t == Types[TUINT8] || t == Bytetype) && (x == Types[TUINT8] || x == Bytetype) {
return CMPeq
}
case TINT32:
if (t == Types[Runetype.Etype] || t == Runetype) && (x == Types[Runetype.Etype] || x == Runetype) {
return CMPeq
}
}
}
if c := t.Sym.cmpsym(x.Sym); c != CMPeq {
return c
}
if x.Sym != nil {
// Syms non-nil, if vargens match then equal.
if t.Vargen != x.Vargen {
return cmpForNe(t.Vargen < x.Vargen)
}
return CMPeq
}
// both syms nil, look at structure below.
switch t.Etype {
case TBOOL, TFLOAT32, TFLOAT64, TCOMPLEX64, TCOMPLEX128, TUNSAFEPTR, TUINTPTR,
TINT8, TINT16, TINT32, TINT64, TINT, TUINT8, TUINT16, TUINT32, TUINT64, TUINT:
return CMPeq
case TSSA:
tname := t.Extra.(string)
xname := t.Extra.(string)
// desire fast sorting, not pretty sorting.
if len(tname) == len(xname) {
if tname == xname {
return CMPeq
}
if tname < xname {
return CMPlt
}
return CMPgt
}
if len(tname) > len(xname) {
return CMPgt
}
return CMPlt
case TTUPLE:
xtup := x.Extra.(*Tuple)
ttup := t.Extra.(*Tuple)
if c := ttup.first.Compare(xtup.first); c != CMPeq {
return c
}
return ttup.second.Compare(xtup.second)
case TMAP:
if c := t.Key().cmp(x.Key()); c != CMPeq {
return c
}
return t.Elem().cmp(x.Elem())
case TPTR, TSLICE:
// No special cases for these, they are handled
// by the general code after the switch.
case TSTRUCT:
if t.StructType().Map == nil {
if x.StructType().Map != nil {
return CMPlt // nil < non-nil
}
// to the fallthrough
} else if x.StructType().Map == nil {
return CMPgt // nil > non-nil
} else if t.StructType().Map.MapType().Bucket == t {
// Both have non-nil Map
// Special case for Maps which include a recursive type where the recursion is not broken with a named type
if x.StructType().Map.MapType().Bucket != x {
return CMPlt // bucket maps are least
}
return t.StructType().Map.cmp(x.StructType().Map)
} else if x.StructType().Map.MapType().Bucket == x {
return CMPgt // bucket maps are least
} // If t != t.Map.Bucket, fall through to general case
tfs := t.FieldSlice()
xfs := x.FieldSlice()
for i := 0; i < len(tfs) && i < len(xfs); i++ {
t1, x1 := tfs[i], xfs[i]
if t1.Embedded != x1.Embedded {
return cmpForNe(t1.Embedded < x1.Embedded)
}
if t1.Note != x1.Note {
return cmpForNe(t1.Note < x1.Note)
}
if c := t1.Sym.cmpsym(x1.Sym); c != CMPeq {
return c
}
if c := t1.Type.cmp(x1.Type); c != CMPeq {
return c
}
}
if len(tfs) != len(xfs) {
return cmpForNe(len(tfs) < len(xfs))
}
return CMPeq
case TINTER:
tfs := t.FieldSlice()
xfs := x.FieldSlice()
for i := 0; i < len(tfs) && i < len(xfs); i++ {
t1, x1 := tfs[i], xfs[i]
if c := t1.Sym.cmpsym(x1.Sym); c != CMPeq {
return c
}
if c := t1.Type.cmp(x1.Type); c != CMPeq {
return c
}
}
if len(tfs) != len(xfs) {
return cmpForNe(len(tfs) < len(xfs))
}
return CMPeq
case TFUNC:
for _, f := range RecvsParamsResults {
// Loop over fields in structs, ignoring argument names.
tfs := f(t).FieldSlice()
xfs := f(x).FieldSlice()
for i := 0; i < len(tfs) && i < len(xfs); i++ {
ta := tfs[i]
tb := xfs[i]
if ta.IsDDD() != tb.IsDDD() {
return cmpForNe(!ta.IsDDD())
}
if c := ta.Type.cmp(tb.Type); c != CMPeq {
return c
}
}
if len(tfs) != len(xfs) {
return cmpForNe(len(tfs) < len(xfs))
}
}
return CMPeq
case TARRAY:
if t.NumElem() != x.NumElem() {
return cmpForNe(t.NumElem() < x.NumElem())
}
case TCHAN:
if t.ChanDir() != x.ChanDir() {
return cmpForNe(t.ChanDir() < x.ChanDir())
}
default:
e := fmt.Sprintf("Do not know how to compare %v with %v", t, x)
panic(e)
}
// Common element type comparison for TARRAY, TCHAN, TPTR, and TSLICE.
return t.Elem().cmp(x.Elem())
}
// IsKind reports whether t is a Type of the specified kind.
func (t *Type) IsKind(et EType) bool {
return t != nil && t.Etype == et
}
func (t *Type) IsBoolean() bool {
return t.Etype == TBOOL
}
var unsignedEType = [...]EType{
TINT8: TUINT8,
TUINT8: TUINT8,
TINT16: TUINT16,
TUINT16: TUINT16,
TINT32: TUINT32,
TUINT32: TUINT32,
TINT64: TUINT64,
TUINT64: TUINT64,
TINT: TUINT,
TUINT: TUINT,
TUINTPTR: TUINTPTR,
}
// ToUnsigned returns the unsigned equivalent of integer type t.
func (t *Type) ToUnsigned() *Type {
if !t.IsInteger() {
Fatalf("unsignedType(%v)", t)
}
return Types[unsignedEType[t.Etype]]
}
func (t *Type) IsInteger() bool {
switch t.Etype {
case TINT8, TUINT8, TINT16, TUINT16, TINT32, TUINT32, TINT64, TUINT64, TINT, TUINT, TUINTPTR:
return true
}
return false
}
func (t *Type) IsSigned() bool {
switch t.Etype {
case TINT8, TINT16, TINT32, TINT64, TINT:
return true
}
return false
}
func (t *Type) IsFloat() bool {
return t.Etype == TFLOAT32 || t.Etype == TFLOAT64
}
func (t *Type) IsComplex() bool {
return t.Etype == TCOMPLEX64 || t.Etype == TCOMPLEX128
}
// IsPtr reports whether t is a regular Go pointer type.
// This does not include unsafe.Pointer.
func (t *Type) IsPtr() bool {
return t.Etype == TPTR
}
// IsPtrElem reports whether t is the element of a pointer (to t).
func (t *Type) IsPtrElem() bool {
return t.Cache.ptr != nil
}
// IsUnsafePtr reports whether t is an unsafe pointer.
func (t *Type) IsUnsafePtr() bool {
return t.Etype == TUNSAFEPTR
}
// IsPtrShaped reports whether t is represented by a single machine pointer.
// In addition to regular Go pointer types, this includes map, channel, and
// function types and unsafe.Pointer. It does not include array or struct types
// that consist of a single pointer shaped type.
// TODO(mdempsky): Should it? See golang.org/issue/15028.
func (t *Type) IsPtrShaped() bool {
return t.Etype == TPTR || t.Etype == TUNSAFEPTR ||
t.Etype == TMAP || t.Etype == TCHAN || t.Etype == TFUNC
}
func (t *Type) IsString() bool {
return t.Etype == TSTRING
}
func (t *Type) IsMap() bool {
return t.Etype == TMAP
}
func (t *Type) IsChan() bool {
return t.Etype == TCHAN
}
func (t *Type) IsSlice() bool {
return t.Etype == TSLICE
}
func (t *Type) IsArray() bool {
return t.Etype == TARRAY
}
func (t *Type) IsStruct() bool {
return t.Etype == TSTRUCT
}
func (t *Type) IsInterface() bool {
return t.Etype == TINTER
}
// IsEmptyInterface reports whether t is an empty interface type.
func (t *Type) IsEmptyInterface() bool {
return t.IsInterface() && t.NumFields() == 0
}
func (t *Type) PtrTo() *Type {
return NewPtr(t)
}
func (t *Type) NumFields() int {
return t.Fields().Len()
}
func (t *Type) FieldType(i int) *Type {
if t.Etype == TTUPLE {
switch i {
case 0:
return t.Extra.(*Tuple).first
case 1:
return t.Extra.(*Tuple).second
default:
panic("bad tuple index")
}
}
return t.Field(i).Type
}
func (t *Type) FieldOff(i int) int64 {
return t.Field(i).Offset
}
func (t *Type) FieldName(i int) string {
return t.Field(i).Sym.Name
}
func (t *Type) NumElem() int64 {
t.wantEtype(TARRAY)
at := t.Extra.(*Array)
if at.Bound < 0 {
Fatalf("NumElem array %v does not have bound yet", t)
}
return at.Bound
}
// SetNumElem sets the number of elements in an array type.
// The only allowed use is on array types created with NewDDDArray.
// For other uses, create a new array with NewArray instead.
func (t *Type) SetNumElem(n int64) {
t.wantEtype(TARRAY)
at := t.Extra.(*Array)
if at.Bound >= 0 {
Fatalf("SetNumElem array %v already has bound %d", t, at.Bound)
}
at.Bound = n
}
type componentsIncludeBlankFields bool
const (
IgnoreBlankFields componentsIncludeBlankFields = false
CountBlankFields componentsIncludeBlankFields = true
)
// NumComponents returns the number of primitive elements that compose t.
// Struct and array types are flattened for the purpose of counting.
// All other types (including string, slice, and interface types) count as one element.
// If countBlank is IgnoreBlankFields, then blank struct fields
// (and their comprised elements) are excluded from the count.
// struct { x, y [3]int } has six components; [10]struct{ x, y string } has twenty.
func (t *Type) NumComponents(countBlank componentsIncludeBlankFields) int64 {
switch t.Etype {
case TSTRUCT:
if t.IsFuncArgStruct() {
Fatalf("NumComponents func arg struct")
}
var n int64
for _, f := range t.FieldSlice() {
if countBlank == IgnoreBlankFields && f.Sym.IsBlank() {
continue
}
n += f.Type.NumComponents(countBlank)
}
return n
case TARRAY:
return t.NumElem() * t.Elem().NumComponents(countBlank)
}
return 1
}
// ChanDir returns the direction of a channel type t.
// The direction will be one of Crecv, Csend, or Cboth.
func (t *Type) ChanDir() ChanDir {
t.wantEtype(TCHAN)
return t.Extra.(*Chan).Dir
}
func (t *Type) IsMemory() bool {
return t == TypeMem || t.Etype == TTUPLE && t.Extra.(*Tuple).second == TypeMem
}
func (t *Type) IsFlags() bool { return t == TypeFlags }
func (t *Type) IsVoid() bool { return t == TypeVoid }
func (t *Type) IsTuple() bool { return t.Etype == TTUPLE }
// IsUntyped reports whether t is an untyped type.
func (t *Type) IsUntyped() bool {
if t == nil {
return false
}
if t == Idealstring || t == Idealbool {
return true
}
switch t.Etype {
case TNIL, TIDEAL:
return true
}
return false
}
// TODO(austin): We probably only need HasHeapPointer. See
// golang.org/cl/73412 for discussion.
func Haspointers(t *Type) bool {
return Haspointers1(t, false)
}
func Haspointers1(t *Type, ignoreNotInHeap bool) bool {
switch t.Etype {
case TINT, TUINT, TINT8, TUINT8, TINT16, TUINT16, TINT32, TUINT32, TINT64,
TUINT64, TUINTPTR, TFLOAT32, TFLOAT64, TCOMPLEX64, TCOMPLEX128, TBOOL, TSSA:
return false
case TARRAY:
if t.NumElem() == 0 { // empty array has no pointers
return false
}
return Haspointers1(t.Elem(), ignoreNotInHeap)
case TSTRUCT:
for _, t1 := range t.Fields().Slice() {
if Haspointers1(t1.Type, ignoreNotInHeap) {
return true
}
}
return false
case TPTR, TSLICE:
return !(ignoreNotInHeap && t.Elem().NotInHeap())
case TTUPLE:
ttup := t.Extra.(*Tuple)
return Haspointers1(ttup.first, ignoreNotInHeap) || Haspointers1(ttup.second, ignoreNotInHeap)
}
return true
}
// HasHeapPointer reports whether t contains a heap pointer.
// This is used for write barrier insertion, so it ignores
// pointers to go:notinheap types.
func (t *Type) HasHeapPointer() bool {
return Haspointers1(t, true)
}
func (t *Type) Symbol() *obj.LSym {
return TypeLinkSym(t)
}
// Tie returns 'T' if t is a concrete type,
// 'I' if t is an interface type, and 'E' if t is an empty interface type.
// It is used to build calls to the conv* and assert* runtime routines.
func (t *Type) Tie() byte {
if t.IsEmptyInterface() {
return 'E'
}
if t.IsInterface() {
return 'I'
}
return 'T'
}
var recvType *Type
// FakeRecvType returns the singleton type used for interface method receivers.
func FakeRecvType() *Type {
if recvType == nil {
recvType = NewPtr(New(TSTRUCT))
}
return recvType
}
var (
// TSSA types. Haspointers assumes these are pointer-free.
TypeInvalid = newSSA("invalid")
TypeMem = newSSA("mem")
TypeFlags = newSSA("flags")
TypeVoid = newSSA("void")
TypeInt128 = newSSA("int128")
)