Your IP : 172.28.240.42
// Copyright 2021 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 noder
import (
"fmt"
"go/constant"
"internal/buildcfg"
"internal/pkgbits"
"path/filepath"
"strings"
"cmd/compile/internal/base"
"cmd/compile/internal/deadcode"
"cmd/compile/internal/dwarfgen"
"cmd/compile/internal/inline"
"cmd/compile/internal/ir"
"cmd/compile/internal/objw"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/staticinit"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/obj"
"cmd/internal/objabi"
"cmd/internal/src"
)
// This file implements cmd/compile backend's reader for the Unified
// IR export data.
// A pkgReader reads Unified IR export data.
type pkgReader struct {
pkgbits.PkgDecoder
// Indices for encoded things; lazily populated as needed.
//
// Note: Objects (i.e., ir.Names) are lazily instantiated by
// populating their types.Sym.Def; see objReader below.
posBases []*src.PosBase
pkgs []*types.Pkg
typs []*types.Type
// offset for rewriting the given (absolute!) index into the output,
// but bitwise inverted so we can detect if we're missing the entry
// or not.
newindex []pkgbits.Index
}
func newPkgReader(pr pkgbits.PkgDecoder) *pkgReader {
return &pkgReader{
PkgDecoder: pr,
posBases: make([]*src.PosBase, pr.NumElems(pkgbits.RelocPosBase)),
pkgs: make([]*types.Pkg, pr.NumElems(pkgbits.RelocPkg)),
typs: make([]*types.Type, pr.NumElems(pkgbits.RelocType)),
newindex: make([]pkgbits.Index, pr.TotalElems()),
}
}
// A pkgReaderIndex compactly identifies an index (and its
// corresponding dictionary) within a package's export data.
type pkgReaderIndex struct {
pr *pkgReader
idx pkgbits.Index
dict *readerDict
methodSym *types.Sym
synthetic func(pos src.XPos, r *reader)
}
func (pri pkgReaderIndex) asReader(k pkgbits.RelocKind, marker pkgbits.SyncMarker) *reader {
if pri.synthetic != nil {
return &reader{synthetic: pri.synthetic}
}
r := pri.pr.newReader(k, pri.idx, marker)
r.dict = pri.dict
r.methodSym = pri.methodSym
return r
}
func (pr *pkgReader) newReader(k pkgbits.RelocKind, idx pkgbits.Index, marker pkgbits.SyncMarker) *reader {
return &reader{
Decoder: pr.NewDecoder(k, idx, marker),
p: pr,
}
}
// A reader provides APIs for reading an individual element.
type reader struct {
pkgbits.Decoder
p *pkgReader
dict *readerDict
// TODO(mdempsky): The state below is all specific to reading
// function bodies. It probably makes sense to split it out
// separately so that it doesn't take up space in every reader
// instance.
curfn *ir.Func
locals []*ir.Name
closureVars []*ir.Name
funarghack bool
// methodSym is the name of method's name, if reading a method.
// It's nil if reading a normal function or closure body.
methodSym *types.Sym
// dictParam is the .dict param, if any.
dictParam *ir.Name
// synthetic is a callback function to construct a synthetic
// function body. It's used for creating the bodies of function
// literals used to curry arguments to shaped functions.
synthetic func(pos src.XPos, r *reader)
// scopeVars is a stack tracking the number of variables declared in
// the current function at the moment each open scope was opened.
scopeVars []int
marker dwarfgen.ScopeMarker
lastCloseScopePos src.XPos
// === details for handling inline body expansion ===
// If we're reading in a function body because of inlining, this is
// the call that we're inlining for.
inlCaller *ir.Func
inlCall *ir.CallExpr
inlFunc *ir.Func
inlTreeIndex int
inlPosBases map[*src.PosBase]*src.PosBase
// suppressInlPos tracks whether position base rewriting for
// inlining should be suppressed. See funcLit.
suppressInlPos int
delayResults bool
// Label to return to.
retlabel *types.Sym
// inlvars is the list of variables that the inlinee's arguments are
// assigned to, one for each receiver and normal parameter, in order.
inlvars ir.Nodes
// retvars is the list of variables that the inlinee's results are
// assigned to, one for each result parameter, in order.
retvars ir.Nodes
}
// A readerDict represents an instantiated "compile-time dictionary,"
// used for resolving any derived types needed for instantiating a
// generic object.
//
// A compile-time dictionary can either be "shaped" or "non-shaped."
// Shaped compile-time dictionaries are only used for instantiating
// shaped type definitions and function bodies, while non-shaped
// compile-time dictionaries are used for instantiating runtime
// dictionaries.
type readerDict struct {
shaped bool // whether this is a shaped dictionary
// baseSym is the symbol for the object this dictionary belongs to.
// If the object is an instantiated function or defined type, then
// baseSym is the mangled symbol, including any type arguments.
baseSym *types.Sym
// For non-shaped dictionaries, shapedObj is a reference to the
// corresponding shaped object (always a function or defined type).
shapedObj *ir.Name
// targs holds the implicit and explicit type arguments in use for
// reading the current object. For example:
//
// func F[T any]() {
// type X[U any] struct { t T; u U }
// var _ X[string]
// }
//
// var _ = F[int]
//
// While instantiating F[int], we need to in turn instantiate
// X[string]. [int] and [string] are explicit type arguments for F
// and X, respectively; but [int] is also the implicit type
// arguments for X.
//
// (As an analogy to function literals, explicits are the function
// literal's formal parameters, while implicits are variables
// captured by the function literal.)
targs []*types.Type
// implicits counts how many of types within targs are implicit type
// arguments; the rest are explicit.
implicits int
derived []derivedInfo // reloc index of the derived type's descriptor
derivedTypes []*types.Type // slice of previously computed derived types
// These slices correspond to entries in the runtime dictionary.
typeParamMethodExprs []readerMethodExprInfo
subdicts []objInfo
rtypes []typeInfo
itabs []itabInfo
}
type readerMethodExprInfo struct {
typeParamIdx int
method *types.Sym
}
func setType(n ir.Node, typ *types.Type) {
n.SetType(typ)
n.SetTypecheck(1)
}
func setValue(name *ir.Name, val constant.Value) {
name.SetVal(val)
name.Defn = nil
}
// @@@ Positions
// pos reads a position from the bitstream.
func (r *reader) pos() src.XPos {
return base.Ctxt.PosTable.XPos(r.pos0())
}
// origPos reads a position from the bitstream, and returns both the
// original raw position and an inlining-adjusted position.
func (r *reader) origPos() (origPos, inlPos src.XPos) {
r.suppressInlPos++
origPos = r.pos()
r.suppressInlPos--
inlPos = r.inlPos(origPos)
return
}
func (r *reader) pos0() src.Pos {
r.Sync(pkgbits.SyncPos)
if !r.Bool() {
return src.NoPos
}
posBase := r.posBase()
line := r.Uint()
col := r.Uint()
return src.MakePos(posBase, line, col)
}
// posBase reads a position base from the bitstream.
func (r *reader) posBase() *src.PosBase {
return r.inlPosBase(r.p.posBaseIdx(r.Reloc(pkgbits.RelocPosBase)))
}
// posBaseIdx returns the specified position base, reading it first if
// needed.
func (pr *pkgReader) posBaseIdx(idx pkgbits.Index) *src.PosBase {
if b := pr.posBases[idx]; b != nil {
return b
}
r := pr.newReader(pkgbits.RelocPosBase, idx, pkgbits.SyncPosBase)
var b *src.PosBase
absFilename := r.String()
filename := absFilename
// For build artifact stability, the export data format only
// contains the "absolute" filename as returned by objabi.AbsFile.
// However, some tests (e.g., test/run.go's asmcheck tests) expect
// to see the full, original filename printed out. Re-expanding
// "$GOROOT" to buildcfg.GOROOT is a close-enough approximation to
// satisfy this.
//
// The export data format only ever uses slash paths
// (for cross-operating-system reproducible builds),
// but error messages need to use native paths (backslash on Windows)
// as if they had been specified on the command line.
// (The go command always passes native paths to the compiler.)
const dollarGOROOT = "$GOROOT"
if buildcfg.GOROOT != "" && strings.HasPrefix(filename, dollarGOROOT) {
filename = filepath.FromSlash(buildcfg.GOROOT + filename[len(dollarGOROOT):])
}
if r.Bool() {
b = src.NewFileBase(filename, absFilename)
} else {
pos := r.pos0()
line := r.Uint()
col := r.Uint()
b = src.NewLinePragmaBase(pos, filename, absFilename, line, col)
}
pr.posBases[idx] = b
return b
}
// inlPosBase returns the inlining-adjusted src.PosBase corresponding
// to oldBase, which must be a non-inlined position. When not
// inlining, this is just oldBase.
func (r *reader) inlPosBase(oldBase *src.PosBase) *src.PosBase {
if index := oldBase.InliningIndex(); index >= 0 {
base.Fatalf("oldBase %v already has inlining index %v", oldBase, index)
}
if r.inlCall == nil || r.suppressInlPos != 0 {
return oldBase
}
if newBase, ok := r.inlPosBases[oldBase]; ok {
return newBase
}
newBase := src.NewInliningBase(oldBase, r.inlTreeIndex)
r.inlPosBases[oldBase] = newBase
return newBase
}
// inlPos returns the inlining-adjusted src.XPos corresponding to
// xpos, which must be a non-inlined position. When not inlining, this
// is just xpos.
func (r *reader) inlPos(xpos src.XPos) src.XPos {
pos := base.Ctxt.PosTable.Pos(xpos)
pos.SetBase(r.inlPosBase(pos.Base()))
return base.Ctxt.PosTable.XPos(pos)
}
// @@@ Packages
// pkg reads a package reference from the bitstream.
func (r *reader) pkg() *types.Pkg {
r.Sync(pkgbits.SyncPkg)
return r.p.pkgIdx(r.Reloc(pkgbits.RelocPkg))
}
// pkgIdx returns the specified package from the export data, reading
// it first if needed.
func (pr *pkgReader) pkgIdx(idx pkgbits.Index) *types.Pkg {
if pkg := pr.pkgs[idx]; pkg != nil {
return pkg
}
pkg := pr.newReader(pkgbits.RelocPkg, idx, pkgbits.SyncPkgDef).doPkg()
pr.pkgs[idx] = pkg
return pkg
}
// doPkg reads a package definition from the bitstream.
func (r *reader) doPkg() *types.Pkg {
path := r.String()
switch path {
case "":
path = r.p.PkgPath()
case "builtin":
return types.BuiltinPkg
case "unsafe":
return types.UnsafePkg
}
name := r.String()
pkg := types.NewPkg(path, "")
if pkg.Name == "" {
pkg.Name = name
} else {
base.Assertf(pkg.Name == name, "package %q has name %q, but want %q", pkg.Path, pkg.Name, name)
}
return pkg
}
// @@@ Types
func (r *reader) typ() *types.Type {
return r.typWrapped(true)
}
// typWrapped is like typ, but allows suppressing generation of
// unnecessary wrappers as a compile-time optimization.
func (r *reader) typWrapped(wrapped bool) *types.Type {
return r.p.typIdx(r.typInfo(), r.dict, wrapped)
}
func (r *reader) typInfo() typeInfo {
r.Sync(pkgbits.SyncType)
if r.Bool() {
return typeInfo{idx: pkgbits.Index(r.Len()), derived: true}
}
return typeInfo{idx: r.Reloc(pkgbits.RelocType), derived: false}
}
// typListIdx returns a list of the specified types, resolving derived
// types within the given dictionary.
func (pr *pkgReader) typListIdx(infos []typeInfo, dict *readerDict) []*types.Type {
typs := make([]*types.Type, len(infos))
for i, info := range infos {
typs[i] = pr.typIdx(info, dict, true)
}
return typs
}
// typIdx returns the specified type. If info specifies a derived
// type, it's resolved within the given dictionary. If wrapped is
// true, then method wrappers will be generated, if appropriate.
func (pr *pkgReader) typIdx(info typeInfo, dict *readerDict, wrapped bool) *types.Type {
idx := info.idx
var where **types.Type
if info.derived {
where = &dict.derivedTypes[idx]
idx = dict.derived[idx].idx
} else {
where = &pr.typs[idx]
}
if typ := *where; typ != nil {
return typ
}
r := pr.newReader(pkgbits.RelocType, idx, pkgbits.SyncTypeIdx)
r.dict = dict
typ := r.doTyp()
assert(typ != nil)
// For recursive type declarations involving interfaces and aliases,
// above r.doTyp() call may have already set pr.typs[idx], so just
// double check and return the type.
//
// Example:
//
// type F = func(I)
//
// type I interface {
// m(F)
// }
//
// The writer writes data types in following index order:
//
// 0: func(I)
// 1: I
// 2: interface{m(func(I))}
//
// The reader resolves it in following index order:
//
// 0 -> 1 -> 2 -> 0 -> 1
//
// and can divide in logically 2 steps:
//
// - 0 -> 1 : first time the reader reach type I,
// it creates new named type with symbol I.
//
// - 2 -> 0 -> 1: the reader ends up reaching symbol I again,
// now the symbol I was setup in above step, so
// the reader just return the named type.
//
// Now, the functions called return, the pr.typs looks like below:
//
// - 0 -> 1 -> 2 -> 0 : [<T> I <T>]
// - 0 -> 1 -> 2 : [func(I) I <T>]
// - 0 -> 1 : [func(I) I interface { "".m(func("".I)) }]
//
// The idx 1, corresponding with type I was resolved successfully
// after r.doTyp() call.
if prev := *where; prev != nil {
return prev
}
if wrapped {
// Only cache if we're adding wrappers, so that other callers that
// find a cached type know it was wrapped.
*where = typ
r.needWrapper(typ)
}
if !typ.IsUntyped() {
types.CheckSize(typ)
}
return typ
}
func (r *reader) doTyp() *types.Type {
switch tag := pkgbits.CodeType(r.Code(pkgbits.SyncType)); tag {
default:
panic(fmt.Sprintf("unexpected type: %v", tag))
case pkgbits.TypeBasic:
return *basics[r.Len()]
case pkgbits.TypeNamed:
obj := r.obj()
assert(obj.Op() == ir.OTYPE)
return obj.Type()
case pkgbits.TypeTypeParam:
return r.dict.targs[r.Len()]
case pkgbits.TypeArray:
len := int64(r.Uint64())
return types.NewArray(r.typ(), len)
case pkgbits.TypeChan:
dir := dirs[r.Len()]
return types.NewChan(r.typ(), dir)
case pkgbits.TypeMap:
return types.NewMap(r.typ(), r.typ())
case pkgbits.TypePointer:
return types.NewPtr(r.typ())
case pkgbits.TypeSignature:
return r.signature(nil)
case pkgbits.TypeSlice:
return types.NewSlice(r.typ())
case pkgbits.TypeStruct:
return r.structType()
case pkgbits.TypeInterface:
return r.interfaceType()
case pkgbits.TypeUnion:
return r.unionType()
}
}
func (r *reader) unionType() *types.Type {
// In the types1 universe, we only need to handle value types.
// Impure interfaces (i.e., interfaces with non-trivial type sets
// like "int | string") can only appear as type parameter bounds,
// and this is enforced by the types2 type checker.
//
// However, type unions can still appear in pure interfaces if the
// type union is equivalent to "any". E.g., typeparam/issue52124.go
// declares variables with the type "interface { any | int }".
//
// To avoid needing to represent type unions in types1 (since we
// don't have any uses for that today anyway), we simply fold them
// to "any".
// TODO(mdempsky): Restore consistency check to make sure folding to
// "any" is safe. This is unfortunately tricky, because a pure
// interface can reference impure interfaces too, including
// cyclically (#60117).
if false {
pure := false
for i, n := 0, r.Len(); i < n; i++ {
_ = r.Bool() // tilde
term := r.typ()
if term.IsEmptyInterface() {
pure = true
}
}
if !pure {
base.Fatalf("impure type set used in value type")
}
}
return types.Types[types.TINTER]
}
func (r *reader) interfaceType() *types.Type {
nmethods, nembeddeds := r.Len(), r.Len()
implicit := nmethods == 0 && nembeddeds == 1 && r.Bool()
assert(!implicit) // implicit interfaces only appear in constraints
fields := make([]*types.Field, nmethods+nembeddeds)
methods, embeddeds := fields[:nmethods], fields[nmethods:]
for i := range methods {
pos := r.pos()
_, sym := r.selector()
mtyp := r.signature(types.FakeRecv())
methods[i] = types.NewField(pos, sym, mtyp)
}
for i := range embeddeds {
embeddeds[i] = types.NewField(src.NoXPos, nil, r.typ())
}
if len(fields) == 0 {
return types.Types[types.TINTER] // empty interface
}
return types.NewInterface(fields)
}
func (r *reader) structType() *types.Type {
fields := make([]*types.Field, r.Len())
for i := range fields {
pos := r.pos()
_, sym := r.selector()
ftyp := r.typ()
tag := r.String()
embedded := r.Bool()
f := types.NewField(pos, sym, ftyp)
f.Note = tag
if embedded {
f.Embedded = 1
}
fields[i] = f
}
return types.NewStruct(fields)
}
func (r *reader) signature(recv *types.Field) *types.Type {
r.Sync(pkgbits.SyncSignature)
params := r.params()
results := r.params()
if r.Bool() { // variadic
params[len(params)-1].SetIsDDD(true)
}
return types.NewSignature(recv, params, results)
}
func (r *reader) params() []*types.Field {
r.Sync(pkgbits.SyncParams)
fields := make([]*types.Field, r.Len())
for i := range fields {
_, fields[i] = r.param()
}
return fields
}
func (r *reader) param() (*types.Pkg, *types.Field) {
r.Sync(pkgbits.SyncParam)
pos := r.pos()
pkg, sym := r.localIdent()
typ := r.typ()
return pkg, types.NewField(pos, sym, typ)
}
// @@@ Objects
// objReader maps qualified identifiers (represented as *types.Sym) to
// a pkgReader and corresponding index that can be used for reading
// that object's definition.
var objReader = map[*types.Sym]pkgReaderIndex{}
// obj reads an instantiated object reference from the bitstream.
func (r *reader) obj() ir.Node {
return r.p.objInstIdx(r.objInfo(), r.dict, false)
}
// objInfo reads an instantiated object reference from the bitstream
// and returns the encoded reference to it, without instantiating it.
func (r *reader) objInfo() objInfo {
r.Sync(pkgbits.SyncObject)
assert(!r.Bool()) // TODO(mdempsky): Remove; was derived func inst.
idx := r.Reloc(pkgbits.RelocObj)
explicits := make([]typeInfo, r.Len())
for i := range explicits {
explicits[i] = r.typInfo()
}
return objInfo{idx, explicits}
}
// objInstIdx returns the encoded, instantiated object. If shaped is
// true, then the shaped variant of the object is returned instead.
func (pr *pkgReader) objInstIdx(info objInfo, dict *readerDict, shaped bool) ir.Node {
explicits := pr.typListIdx(info.explicits, dict)
var implicits []*types.Type
if dict != nil {
implicits = dict.targs
}
return pr.objIdx(info.idx, implicits, explicits, shaped)
}
// objIdx returns the specified object, instantiated with the given
// type arguments, if any. If shaped is true, then the shaped variant
// of the object is returned instead.
func (pr *pkgReader) objIdx(idx pkgbits.Index, implicits, explicits []*types.Type, shaped bool) ir.Node {
rname := pr.newReader(pkgbits.RelocName, idx, pkgbits.SyncObject1)
_, sym := rname.qualifiedIdent()
tag := pkgbits.CodeObj(rname.Code(pkgbits.SyncCodeObj))
if tag == pkgbits.ObjStub {
assert(!sym.IsBlank())
switch sym.Pkg {
case types.BuiltinPkg, types.UnsafePkg:
return sym.Def.(ir.Node)
}
if pri, ok := objReader[sym]; ok {
return pri.pr.objIdx(pri.idx, nil, explicits, shaped)
}
base.Fatalf("unresolved stub: %v", sym)
}
dict := pr.objDictIdx(sym, idx, implicits, explicits, shaped)
sym = dict.baseSym
if !sym.IsBlank() && sym.Def != nil {
return sym.Def.(*ir.Name)
}
r := pr.newReader(pkgbits.RelocObj, idx, pkgbits.SyncObject1)
rext := pr.newReader(pkgbits.RelocObjExt, idx, pkgbits.SyncObject1)
r.dict = dict
rext.dict = dict
do := func(op ir.Op, hasTParams bool) *ir.Name {
pos := r.pos()
setBasePos(pos)
if hasTParams {
r.typeParamNames()
}
name := ir.NewDeclNameAt(pos, op, sym)
name.Class = ir.PEXTERN // may be overridden later
if !sym.IsBlank() {
if sym.Def != nil {
base.FatalfAt(name.Pos(), "already have a definition for %v", name)
}
assert(sym.Def == nil)
sym.Def = name
}
return name
}
switch tag {
default:
panic("unexpected object")
case pkgbits.ObjAlias:
name := do(ir.OTYPE, false)
setType(name, r.typ())
name.SetAlias(true)
return name
case pkgbits.ObjConst:
name := do(ir.OLITERAL, false)
typ := r.typ()
val := FixValue(typ, r.Value())
setType(name, typ)
setValue(name, val)
return name
case pkgbits.ObjFunc:
if sym.Name == "init" {
sym = Renameinit()
}
name := do(ir.ONAME, true)
setType(name, r.signature(nil))
name.Func = ir.NewFunc(r.pos())
name.Func.Nname = name
if r.hasTypeParams() {
name.Func.SetDupok(true)
if r.dict.shaped {
setType(name, shapeSig(name.Func, r.dict))
} else {
todoDicts = append(todoDicts, func() {
r.dict.shapedObj = pr.objIdx(idx, implicits, explicits, true).(*ir.Name)
})
}
}
rext.funcExt(name, nil)
return name
case pkgbits.ObjType:
name := do(ir.OTYPE, true)
typ := types.NewNamed(name)
setType(name, typ)
if r.hasTypeParams() && r.dict.shaped {
typ.SetHasShape(true)
}
// Important: We need to do this before SetUnderlying.
rext.typeExt(name)
// We need to defer CheckSize until we've called SetUnderlying to
// handle recursive types.
types.DeferCheckSize()
typ.SetUnderlying(r.typWrapped(false))
types.ResumeCheckSize()
if r.hasTypeParams() && !r.dict.shaped {
todoDicts = append(todoDicts, func() {
r.dict.shapedObj = pr.objIdx(idx, implicits, explicits, true).(*ir.Name)
})
}
methods := make([]*types.Field, r.Len())
for i := range methods {
methods[i] = r.method(rext)
}
if len(methods) != 0 {
typ.Methods().Set(methods)
}
if !r.dict.shaped {
r.needWrapper(typ)
}
return name
case pkgbits.ObjVar:
name := do(ir.ONAME, false)
setType(name, r.typ())
rext.varExt(name)
return name
}
}
func (dict *readerDict) mangle(sym *types.Sym) *types.Sym {
if !dict.hasTypeParams() {
return sym
}
// If sym is a locally defined generic type, we need the suffix to
// stay at the end after mangling so that types/fmt.go can strip it
// out again when writing the type's runtime descriptor (#54456).
base, suffix := types.SplitVargenSuffix(sym.Name)
var buf strings.Builder
buf.WriteString(base)
buf.WriteByte('[')
for i, targ := range dict.targs {
if i > 0 {
if i == dict.implicits {
buf.WriteByte(';')
} else {
buf.WriteByte(',')
}
}
buf.WriteString(targ.LinkString())
}
buf.WriteByte(']')
buf.WriteString(suffix)
return sym.Pkg.Lookup(buf.String())
}
// shapify returns the shape type for targ.
//
// If basic is true, then the type argument is used to instantiate a
// type parameter whose constraint is a basic interface.
func shapify(targ *types.Type, basic bool) *types.Type {
if targ.Kind() == types.TFORW {
if targ.IsFullyInstantiated() {
// For recursive instantiated type argument, it may still be a TFORW
// when shapifying happens. If we don't have targ's underlying type,
// shapify won't work. The worst case is we end up not reusing code
// optimally in some tricky cases.
if base.Debug.Shapify != 0 {
base.Warn("skipping shaping of recursive type %v", targ)
}
if targ.HasShape() {
return targ
}
} else {
base.Fatalf("%v is missing its underlying type", targ)
}
}
// When a pointer type is used to instantiate a type parameter
// constrained by a basic interface, we know the pointer's element
// type can't matter to the generated code. In this case, we can use
// an arbitrary pointer type as the shape type. (To match the
// non-unified frontend, we use `*byte`.)
//
// Otherwise, we simply use the type's underlying type as its shape.
//
// TODO(mdempsky): It should be possible to do much more aggressive
// shaping still; e.g., collapsing all pointer-shaped types into a
// common type, collapsing scalars of the same size/alignment into a
// common type, recursively shaping the element types of composite
// types, and discarding struct field names and tags. However, we'll
// need to start tracking how type parameters are actually used to
// implement some of these optimizations.
under := targ.Underlying()
if basic && targ.IsPtr() && !targ.Elem().NotInHeap() {
under = types.NewPtr(types.Types[types.TUINT8])
}
sym := types.ShapePkg.Lookup(under.LinkString())
if sym.Def == nil {
name := ir.NewDeclNameAt(under.Pos(), ir.OTYPE, sym)
typ := types.NewNamed(name)
typ.SetUnderlying(under)
sym.Def = typed(typ, name)
}
res := sym.Def.Type()
assert(res.IsShape())
assert(res.HasShape())
return res
}
// objDictIdx reads and returns the specified object dictionary.
func (pr *pkgReader) objDictIdx(sym *types.Sym, idx pkgbits.Index, implicits, explicits []*types.Type, shaped bool) *readerDict {
r := pr.newReader(pkgbits.RelocObjDict, idx, pkgbits.SyncObject1)
dict := readerDict{
shaped: shaped,
}
nimplicits := r.Len()
nexplicits := r.Len()
if nimplicits > len(implicits) || nexplicits != len(explicits) {
base.Fatalf("%v has %v+%v params, but instantiated with %v+%v args", sym, nimplicits, nexplicits, len(implicits), len(explicits))
}
dict.targs = append(implicits[:nimplicits:nimplicits], explicits...)
dict.implicits = nimplicits
// Within the compiler, we can just skip over the type parameters.
for range dict.targs[dict.implicits:] {
// Skip past bounds without actually evaluating them.
r.typInfo()
}
dict.derived = make([]derivedInfo, r.Len())
dict.derivedTypes = make([]*types.Type, len(dict.derived))
for i := range dict.derived {
dict.derived[i] = derivedInfo{r.Reloc(pkgbits.RelocType), r.Bool()}
}
// Runtime dictionary information; private to the compiler.
// If any type argument is already shaped, then we're constructing a
// shaped object, even if not explicitly requested (i.e., calling
// objIdx with shaped==true). This can happen with instantiating
// types that are referenced within a function body.
for _, targ := range dict.targs {
if targ.HasShape() {
dict.shaped = true
break
}
}
// And if we're constructing a shaped object, then shapify all type
// arguments.
for i, targ := range dict.targs {
basic := r.Bool()
if dict.shaped {
dict.targs[i] = shapify(targ, basic)
}
}
dict.baseSym = dict.mangle(sym)
dict.typeParamMethodExprs = make([]readerMethodExprInfo, r.Len())
for i := range dict.typeParamMethodExprs {
typeParamIdx := r.Len()
_, method := r.selector()
dict.typeParamMethodExprs[i] = readerMethodExprInfo{typeParamIdx, method}
}
dict.subdicts = make([]objInfo, r.Len())
for i := range dict.subdicts {
dict.subdicts[i] = r.objInfo()
}
dict.rtypes = make([]typeInfo, r.Len())
for i := range dict.rtypes {
dict.rtypes[i] = r.typInfo()
}
dict.itabs = make([]itabInfo, r.Len())
for i := range dict.itabs {
dict.itabs[i] = itabInfo{typ: r.typInfo(), iface: r.typInfo()}
}
return &dict
}
func (r *reader) typeParamNames() {
r.Sync(pkgbits.SyncTypeParamNames)
for range r.dict.targs[r.dict.implicits:] {
r.pos()
r.localIdent()
}
}
func (r *reader) method(rext *reader) *types.Field {
r.Sync(pkgbits.SyncMethod)
pos := r.pos()
_, sym := r.selector()
r.typeParamNames()
_, recv := r.param()
typ := r.signature(recv)
name := ir.NewNameAt(pos, ir.MethodSym(recv.Type, sym))
setType(name, typ)
name.Func = ir.NewFunc(r.pos())
name.Func.Nname = name
if r.hasTypeParams() {
name.Func.SetDupok(true)
if r.dict.shaped {
typ = shapeSig(name.Func, r.dict)
setType(name, typ)
}
}
rext.funcExt(name, sym)
meth := types.NewField(name.Func.Pos(), sym, typ)
meth.Nname = name
meth.SetNointerface(name.Func.Pragma&ir.Nointerface != 0)
return meth
}
func (r *reader) qualifiedIdent() (pkg *types.Pkg, sym *types.Sym) {
r.Sync(pkgbits.SyncSym)
pkg = r.pkg()
if name := r.String(); name != "" {
sym = pkg.Lookup(name)
}
return
}
func (r *reader) localIdent() (pkg *types.Pkg, sym *types.Sym) {
r.Sync(pkgbits.SyncLocalIdent)
pkg = r.pkg()
if name := r.String(); name != "" {
sym = pkg.Lookup(name)
}
return
}
func (r *reader) selector() (origPkg *types.Pkg, sym *types.Sym) {
r.Sync(pkgbits.SyncSelector)
origPkg = r.pkg()
name := r.String()
pkg := origPkg
if types.IsExported(name) {
pkg = types.LocalPkg
}
sym = pkg.Lookup(name)
return
}
func (r *reader) hasTypeParams() bool {
return r.dict.hasTypeParams()
}
func (dict *readerDict) hasTypeParams() bool {
return dict != nil && len(dict.targs) != 0
}
// @@@ Compiler extensions
func (r *reader) funcExt(name *ir.Name, method *types.Sym) {
r.Sync(pkgbits.SyncFuncExt)
name.Class = 0 // so MarkFunc doesn't complain
ir.MarkFunc(name)
fn := name.Func
// XXX: Workaround because linker doesn't know how to copy Pos.
if !fn.Pos().IsKnown() {
fn.SetPos(name.Pos())
}
// Normally, we only compile local functions, which saves redundant compilation work.
// n.Defn is not nil for local functions, and is nil for imported function. But for
// generic functions, we might have an instantiation that no other package has seen before.
// So we need to be conservative and compile it again.
//
// That's why name.Defn is set here, so ir.VisitFuncsBottomUp can analyze function.
// TODO(mdempsky,cuonglm): find a cleaner way to handle this.
if name.Sym().Pkg == types.LocalPkg || r.hasTypeParams() {
name.Defn = fn
}
fn.Pragma = r.pragmaFlag()
r.linkname(name)
if buildcfg.GOARCH == "wasm" {
xmod := r.String()
xname := r.String()
if xmod != "" && xname != "" {
fn.WasmImport = &ir.WasmImport{
Module: xmod,
Name: xname,
}
}
}
typecheck.Func(fn)
if r.Bool() {
assert(name.Defn == nil)
fn.ABI = obj.ABI(r.Uint64())
// Escape analysis.
for _, fs := range &types.RecvsParams {
for _, f := range fs(name.Type()).FieldSlice() {
f.Note = r.String()
}
}
if r.Bool() {
fn.Inl = &ir.Inline{
Cost: int32(r.Len()),
CanDelayResults: r.Bool(),
}
}
} else {
r.addBody(name.Func, method)
}
r.Sync(pkgbits.SyncEOF)
}
func (r *reader) typeExt(name *ir.Name) {
r.Sync(pkgbits.SyncTypeExt)
typ := name.Type()
if r.hasTypeParams() {
// Set "RParams" (really type arguments here, not parameters) so
// this type is treated as "fully instantiated". This ensures the
// type descriptor is written out as DUPOK and method wrappers are
// generated even for imported types.
var targs []*types.Type
targs = append(targs, r.dict.targs...)
typ.SetRParams(targs)
}
name.SetPragma(r.pragmaFlag())
typecheck.SetBaseTypeIndex(typ, r.Int64(), r.Int64())
}
func (r *reader) varExt(name *ir.Name) {
r.Sync(pkgbits.SyncVarExt)
r.linkname(name)
}
func (r *reader) linkname(name *ir.Name) {
assert(name.Op() == ir.ONAME)
r.Sync(pkgbits.SyncLinkname)
if idx := r.Int64(); idx >= 0 {
lsym := name.Linksym()
lsym.SymIdx = int32(idx)
lsym.Set(obj.AttrIndexed, true)
} else {
name.Sym().Linkname = r.String()
}
}
func (r *reader) pragmaFlag() ir.PragmaFlag {
r.Sync(pkgbits.SyncPragma)
return ir.PragmaFlag(r.Int())
}
// @@@ Function bodies
// bodyReader tracks where the serialized IR for a local or imported,
// generic function's body can be found.
var bodyReader = map[*ir.Func]pkgReaderIndex{}
// importBodyReader tracks where the serialized IR for an imported,
// static (i.e., non-generic) function body can be read.
var importBodyReader = map[*types.Sym]pkgReaderIndex{}
// bodyReaderFor returns the pkgReaderIndex for reading fn's
// serialized IR, and whether one was found.
func bodyReaderFor(fn *ir.Func) (pri pkgReaderIndex, ok bool) {
if fn.Nname.Defn != nil {
pri, ok = bodyReader[fn]
base.AssertfAt(ok, base.Pos, "must have bodyReader for %v", fn) // must always be available
} else {
pri, ok = importBodyReader[fn.Sym()]
}
return
}
// todoDicts holds the list of dictionaries that still need their
// runtime dictionary objects constructed.
var todoDicts []func()
// todoBodies holds the list of function bodies that still need to be
// constructed.
var todoBodies []*ir.Func
// addBody reads a function body reference from the element bitstream,
// and associates it with fn.
func (r *reader) addBody(fn *ir.Func, method *types.Sym) {
// addBody should only be called for local functions or imported
// generic functions; see comment in funcExt.
assert(fn.Nname.Defn != nil)
idx := r.Reloc(pkgbits.RelocBody)
pri := pkgReaderIndex{r.p, idx, r.dict, method, nil}
bodyReader[fn] = pri
if r.curfn == nil {
todoBodies = append(todoBodies, fn)
return
}
pri.funcBody(fn)
}
func (pri pkgReaderIndex) funcBody(fn *ir.Func) {
r := pri.asReader(pkgbits.RelocBody, pkgbits.SyncFuncBody)
r.funcBody(fn)
}
// funcBody reads a function body definition from the element
// bitstream, and populates fn with it.
func (r *reader) funcBody(fn *ir.Func) {
r.curfn = fn
r.closureVars = fn.ClosureVars
if len(r.closureVars) != 0 && r.hasTypeParams() {
r.dictParam = r.closureVars[len(r.closureVars)-1] // dictParam is last; see reader.funcLit
}
ir.WithFunc(fn, func() {
r.funcargs(fn)
if r.syntheticBody(fn.Pos()) {
return
}
if !r.Bool() {
return
}
body := r.stmts()
if body == nil {
body = []ir.Node{typecheck.Stmt(ir.NewBlockStmt(src.NoXPos, nil))}
}
fn.Body = body
fn.Endlineno = r.pos()
})
r.marker.WriteTo(fn)
}
// syntheticBody adds a synthetic body to r.curfn if appropriate, and
// reports whether it did.
func (r *reader) syntheticBody(pos src.XPos) bool {
if r.synthetic != nil {
r.synthetic(pos, r)
return true
}
// If this function has type parameters and isn't shaped, then we
// just tail call its corresponding shaped variant.
if r.hasTypeParams() && !r.dict.shaped {
r.callShaped(pos)
return true
}
return false
}
// callShaped emits a tail call to r.shapedFn, passing along the
// arguments to the current function.
func (r *reader) callShaped(pos src.XPos) {
shapedObj := r.dict.shapedObj
assert(shapedObj != nil)
var shapedFn ir.Node
if r.methodSym == nil {
// Instantiating a generic function; shapedObj is the shaped
// function itself.
assert(shapedObj.Op() == ir.ONAME && shapedObj.Class == ir.PFUNC)
shapedFn = shapedObj
} else {
// Instantiating a generic type's method; shapedObj is the shaped
// type, so we need to select it's corresponding method.
shapedFn = shapedMethodExpr(pos, shapedObj, r.methodSym)
}
recvs, params := r.syntheticArgs(pos)
// Construct the arguments list: receiver (if any), then runtime
// dictionary, and finally normal parameters.
//
// Note: For simplicity, shaped methods are added as normal methods
// on their shaped types. So existing code (e.g., packages ir and
// typecheck) expects the shaped type to appear as the receiver
// parameter (or first parameter, as a method expression). Hence
// putting the dictionary parameter after that is the least invasive
// solution at the moment.
var args ir.Nodes
args.Append(recvs...)
args.Append(typecheck.Expr(ir.NewAddrExpr(pos, r.p.dictNameOf(r.dict))))
args.Append(params...)
r.syntheticTailCall(pos, shapedFn, args)
}
// syntheticArgs returns the recvs and params arguments passed to the
// current function.
func (r *reader) syntheticArgs(pos src.XPos) (recvs, params ir.Nodes) {
sig := r.curfn.Nname.Type()
inlVarIdx := 0
addParams := func(out *ir.Nodes, params []*types.Field) {
for _, param := range params {
var arg ir.Node
if param.Nname != nil {
name := param.Nname.(*ir.Name)
if !ir.IsBlank(name) {
if r.inlCall != nil {
// During inlining, we want the respective inlvar where we
// assigned the callee's arguments.
arg = r.inlvars[inlVarIdx]
} else {
// Otherwise, we can use the parameter itself directly.
base.AssertfAt(name.Curfn == r.curfn, name.Pos(), "%v has curfn %v, but want %v", name, name.Curfn, r.curfn)
arg = name
}
}
}
// For anonymous and blank parameters, we don't have an *ir.Name
// to use as the argument. However, since we know the shaped
// function won't use the value either, we can just pass the
// zero value. (Also unfortunately, we don't have an easy
// zero-value IR node; so we use a default-initialized temporary
// variable.)
if arg == nil {
tmp := typecheck.TempAt(pos, r.curfn, param.Type)
r.curfn.Body.Append(
typecheck.Stmt(ir.NewDecl(pos, ir.ODCL, tmp)),
typecheck.Stmt(ir.NewAssignStmt(pos, tmp, nil)),
)
arg = tmp
}
out.Append(arg)
inlVarIdx++
}
}
addParams(&recvs, sig.Recvs().FieldSlice())
addParams(¶ms, sig.Params().FieldSlice())
return
}
// syntheticTailCall emits a tail call to fn, passing the given
// arguments list.
func (r *reader) syntheticTailCall(pos src.XPos, fn ir.Node, args ir.Nodes) {
// Mark the function as a wrapper so it doesn't show up in stack
// traces.
r.curfn.SetWrapper(true)
call := typecheck.Call(pos, fn, args, fn.Type().IsVariadic()).(*ir.CallExpr)
var stmt ir.Node
if fn.Type().NumResults() != 0 {
stmt = typecheck.Stmt(ir.NewReturnStmt(pos, []ir.Node{call}))
} else {
stmt = call
}
r.curfn.Body.Append(stmt)
}
// dictNameOf returns the runtime dictionary corresponding to dict.
func (pr *pkgReader) dictNameOf(dict *readerDict) *ir.Name {
pos := base.AutogeneratedPos
// Check that we only instantiate runtime dictionaries with real types.
base.AssertfAt(!dict.shaped, pos, "runtime dictionary of shaped object %v", dict.baseSym)
sym := dict.baseSym.Pkg.Lookup(objabi.GlobalDictPrefix + "." + dict.baseSym.Name)
if sym.Def != nil {
return sym.Def.(*ir.Name)
}
name := ir.NewNameAt(pos, sym)
name.Class = ir.PEXTERN
sym.Def = name // break cycles with mutual subdictionaries
lsym := name.Linksym()
ot := 0
assertOffset := func(section string, offset int) {
base.AssertfAt(ot == offset*types.PtrSize, pos, "writing section %v at offset %v, but it should be at %v*%v", section, ot, offset, types.PtrSize)
}
assertOffset("type param method exprs", dict.typeParamMethodExprsOffset())
for _, info := range dict.typeParamMethodExprs {
typeParam := dict.targs[info.typeParamIdx]
method := typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(typeParam), info.method)).(*ir.SelectorExpr)
assert(method.Op() == ir.OMETHEXPR)
rsym := method.FuncName().Linksym()
assert(rsym.ABI() == obj.ABIInternal) // must be ABIInternal; see ir.OCFUNC in ssagen/ssa.go
ot = objw.SymPtr(lsym, ot, rsym, 0)
}
assertOffset("subdictionaries", dict.subdictsOffset())
for _, info := range dict.subdicts {
explicits := pr.typListIdx(info.explicits, dict)
// Careful: Due to subdictionary cycles, name may not be fully
// initialized yet.
name := pr.objDictName(info.idx, dict.targs, explicits)
ot = objw.SymPtr(lsym, ot, name.Linksym(), 0)
}
assertOffset("rtypes", dict.rtypesOffset())
for _, info := range dict.rtypes {
typ := pr.typIdx(info, dict, true)
ot = objw.SymPtr(lsym, ot, reflectdata.TypeLinksym(typ), 0)
// TODO(mdempsky): Double check this.
reflectdata.MarkTypeUsedInInterface(typ, lsym)
}
// For each (typ, iface) pair, we write the *runtime.itab pointer
// for the pair. For pairs that don't actually require an itab
// (i.e., typ is an interface, or iface is an empty interface), we
// write a nil pointer instead. This is wasteful, but rare in
// practice (e.g., instantiating a type parameter with an interface
// type).
assertOffset("itabs", dict.itabsOffset())
for _, info := range dict.itabs {
typ := pr.typIdx(info.typ, dict, true)
iface := pr.typIdx(info.iface, dict, true)
if !typ.IsInterface() && iface.IsInterface() && !iface.IsEmptyInterface() {
ot = objw.SymPtr(lsym, ot, reflectdata.ITabLsym(typ, iface), 0)
} else {
ot += types.PtrSize
}
// TODO(mdempsky): Double check this.
reflectdata.MarkTypeUsedInInterface(typ, lsym)
reflectdata.MarkTypeUsedInInterface(iface, lsym)
}
objw.Global(lsym, int32(ot), obj.DUPOK|obj.RODATA)
name.SetType(dict.varType())
name.SetTypecheck(1)
return name
}
// typeParamMethodExprsOffset returns the offset of the runtime
// dictionary's type parameter method expressions section, in words.
func (dict *readerDict) typeParamMethodExprsOffset() int {
return 0
}
// subdictsOffset returns the offset of the runtime dictionary's
// subdictionary section, in words.
func (dict *readerDict) subdictsOffset() int {
return dict.typeParamMethodExprsOffset() + len(dict.typeParamMethodExprs)
}
// rtypesOffset returns the offset of the runtime dictionary's rtypes
// section, in words.
func (dict *readerDict) rtypesOffset() int {
return dict.subdictsOffset() + len(dict.subdicts)
}
// itabsOffset returns the offset of the runtime dictionary's itabs
// section, in words.
func (dict *readerDict) itabsOffset() int {
return dict.rtypesOffset() + len(dict.rtypes)
}
// numWords returns the total number of words that comprise dict's
// runtime dictionary variable.
func (dict *readerDict) numWords() int64 {
return int64(dict.itabsOffset() + len(dict.itabs))
}
// varType returns the type of dict's runtime dictionary variable.
func (dict *readerDict) varType() *types.Type {
return types.NewArray(types.Types[types.TUINTPTR], dict.numWords())
}
func (r *reader) funcargs(fn *ir.Func) {
sig := fn.Nname.Type()
if recv := sig.Recv(); recv != nil {
r.funcarg(recv, recv.Sym, ir.PPARAM)
}
for _, param := range sig.Params().FieldSlice() {
r.funcarg(param, param.Sym, ir.PPARAM)
}
for i, param := range sig.Results().FieldSlice() {
sym := types.OrigSym(param.Sym)
if sym == nil || sym.IsBlank() {
prefix := "~r"
if r.inlCall != nil {
prefix = "~R"
} else if sym != nil {
prefix = "~b"
}
sym = typecheck.LookupNum(prefix, i)
}
r.funcarg(param, sym, ir.PPARAMOUT)
}
}
func (r *reader) funcarg(param *types.Field, sym *types.Sym, ctxt ir.Class) {
if sym == nil {
assert(ctxt == ir.PPARAM)
if r.inlCall != nil {
r.inlvars.Append(ir.BlankNode)
}
return
}
name := ir.NewNameAt(r.inlPos(param.Pos), sym)
setType(name, param.Type)
r.addLocal(name, ctxt)
if r.inlCall == nil {
if !r.funarghack {
param.Sym = sym
param.Nname = name
}
} else {
if ctxt == ir.PPARAMOUT {
r.retvars.Append(name)
} else {
r.inlvars.Append(name)
}
}
}
func (r *reader) addLocal(name *ir.Name, ctxt ir.Class) {
assert(ctxt == ir.PAUTO || ctxt == ir.PPARAM || ctxt == ir.PPARAMOUT)
if name.Sym().Name == dictParamName {
r.dictParam = name
} else {
if r.synthetic == nil {
r.Sync(pkgbits.SyncAddLocal)
if r.p.SyncMarkers() {
want := r.Int()
if have := len(r.locals); have != want {
base.FatalfAt(name.Pos(), "locals table has desynced")
}
}
r.varDictIndex(name)
}
r.locals = append(r.locals, name)
}
name.SetUsed(true)
// TODO(mdempsky): Move earlier.
if ir.IsBlank(name) {
return
}
if r.inlCall != nil {
if ctxt == ir.PAUTO {
name.SetInlLocal(true)
} else {
name.SetInlFormal(true)
ctxt = ir.PAUTO
}
}
name.Class = ctxt
name.Curfn = r.curfn
r.curfn.Dcl = append(r.curfn.Dcl, name)
if ctxt == ir.PAUTO {
name.SetFrameOffset(0)
}
}
func (r *reader) useLocal() *ir.Name {
r.Sync(pkgbits.SyncUseObjLocal)
if r.Bool() {
return r.locals[r.Len()]
}
return r.closureVars[r.Len()]
}
func (r *reader) openScope() {
r.Sync(pkgbits.SyncOpenScope)
pos := r.pos()
if base.Flag.Dwarf {
r.scopeVars = append(r.scopeVars, len(r.curfn.Dcl))
r.marker.Push(pos)
}
}
func (r *reader) closeScope() {
r.Sync(pkgbits.SyncCloseScope)
r.lastCloseScopePos = r.pos()
r.closeAnotherScope()
}
// closeAnotherScope is like closeScope, but it reuses the same mark
// position as the last closeScope call. This is useful for "for" and
// "if" statements, as their implicit blocks always end at the same
// position as an explicit block.
func (r *reader) closeAnotherScope() {
r.Sync(pkgbits.SyncCloseAnotherScope)
if base.Flag.Dwarf {
scopeVars := r.scopeVars[len(r.scopeVars)-1]
r.scopeVars = r.scopeVars[:len(r.scopeVars)-1]
// Quirkish: noder decides which scopes to keep before
// typechecking, whereas incremental typechecking during IR
// construction can result in new autotemps being allocated. To
// produce identical output, we ignore autotemps here for the
// purpose of deciding whether to retract the scope.
//
// This is important for net/http/fcgi, because it contains:
//
// var body io.ReadCloser
// if len(content) > 0 {
// body, req.pw = io.Pipe()
// } else { … }
//
// Notably, io.Pipe is inlinable, and inlining it introduces a ~R0
// variable at the call site.
//
// Noder does not preserve the scope where the io.Pipe() call
// resides, because it doesn't contain any declared variables in
// source. So the ~R0 variable ends up being assigned to the
// enclosing scope instead.
//
// However, typechecking this assignment also introduces
// autotemps, because io.Pipe's results need conversion before
// they can be assigned to their respective destination variables.
//
// TODO(mdempsky): We should probably just keep all scopes, and
// let dwarfgen take care of pruning them instead.
retract := true
for _, n := range r.curfn.Dcl[scopeVars:] {
if !n.AutoTemp() {
retract = false
break
}
}
if retract {
// no variables were declared in this scope, so we can retract it.
r.marker.Unpush()
} else {
r.marker.Pop(r.lastCloseScopePos)
}
}
}
// @@@ Statements
func (r *reader) stmt() ir.Node {
switch stmts := r.stmts(); len(stmts) {
case 0:
return nil
case 1:
return stmts[0]
default:
return ir.NewBlockStmt(stmts[0].Pos(), stmts)
}
}
func (r *reader) stmts() []ir.Node {
assert(ir.CurFunc == r.curfn)
var res ir.Nodes
r.Sync(pkgbits.SyncStmts)
for {
tag := codeStmt(r.Code(pkgbits.SyncStmt1))
if tag == stmtEnd {
r.Sync(pkgbits.SyncStmtsEnd)
return res
}
if n := r.stmt1(tag, &res); n != nil {
res.Append(typecheck.Stmt(n))
}
}
}
func (r *reader) stmt1(tag codeStmt, out *ir.Nodes) ir.Node {
var label *types.Sym
if n := len(*out); n > 0 {
if ls, ok := (*out)[n-1].(*ir.LabelStmt); ok {
label = ls.Label
}
}
switch tag {
default:
panic("unexpected statement")
case stmtAssign:
pos := r.pos()
names, lhs := r.assignList()
rhs := r.multiExpr()
if len(rhs) == 0 {
for _, name := range names {
as := ir.NewAssignStmt(pos, name, nil)
as.PtrInit().Append(ir.NewDecl(pos, ir.ODCL, name))
out.Append(typecheck.Stmt(as))
}
return nil
}
if len(lhs) == 1 && len(rhs) == 1 {
n := ir.NewAssignStmt(pos, lhs[0], rhs[0])
n.Def = r.initDefn(n, names)
return n
}
n := ir.NewAssignListStmt(pos, ir.OAS2, lhs, rhs)
n.Def = r.initDefn(n, names)
return n
case stmtAssignOp:
op := r.op()
lhs := r.expr()
pos := r.pos()
rhs := r.expr()
return ir.NewAssignOpStmt(pos, op, lhs, rhs)
case stmtIncDec:
op := r.op()
lhs := r.expr()
pos := r.pos()
n := ir.NewAssignOpStmt(pos, op, lhs, ir.NewBasicLit(pos, one))
n.IncDec = true
return n
case stmtBlock:
out.Append(r.blockStmt()...)
return nil
case stmtBranch:
pos := r.pos()
op := r.op()
sym := r.optLabel()
return ir.NewBranchStmt(pos, op, sym)
case stmtCall:
pos := r.pos()
op := r.op()
call := r.expr()
return ir.NewGoDeferStmt(pos, op, call)
case stmtExpr:
return r.expr()
case stmtFor:
return r.forStmt(label)
case stmtIf:
return r.ifStmt()
case stmtLabel:
pos := r.pos()
sym := r.label()
return ir.NewLabelStmt(pos, sym)
case stmtReturn:
pos := r.pos()
results := r.multiExpr()
return ir.NewReturnStmt(pos, results)
case stmtSelect:
return r.selectStmt(label)
case stmtSend:
pos := r.pos()
ch := r.expr()
value := r.expr()
return ir.NewSendStmt(pos, ch, value)
case stmtSwitch:
return r.switchStmt(label)
}
}
func (r *reader) assignList() ([]*ir.Name, []ir.Node) {
lhs := make([]ir.Node, r.Len())
var names []*ir.Name
for i := range lhs {
expr, def := r.assign()
lhs[i] = expr
if def {
names = append(names, expr.(*ir.Name))
}
}
return names, lhs
}
// assign returns an assignee expression. It also reports whether the
// returned expression is a newly declared variable.
func (r *reader) assign() (ir.Node, bool) {
switch tag := codeAssign(r.Code(pkgbits.SyncAssign)); tag {
default:
panic("unhandled assignee expression")
case assignBlank:
return typecheck.AssignExpr(ir.BlankNode), false
case assignDef:
pos := r.pos()
setBasePos(pos)
_, sym := r.localIdent()
typ := r.typ()
name := ir.NewNameAt(pos, sym)
setType(name, typ)
r.addLocal(name, ir.PAUTO)
return name, true
case assignExpr:
return r.expr(), false
}
}
func (r *reader) blockStmt() []ir.Node {
r.Sync(pkgbits.SyncBlockStmt)
r.openScope()
stmts := r.stmts()
r.closeScope()
return stmts
}
func (r *reader) forStmt(label *types.Sym) ir.Node {
r.Sync(pkgbits.SyncForStmt)
r.openScope()
if r.Bool() {
pos := r.pos()
rang := ir.NewRangeStmt(pos, nil, nil, nil, nil, false)
rang.Label = label
names, lhs := r.assignList()
if len(lhs) >= 1 {
rang.Key = lhs[0]
if len(lhs) >= 2 {
rang.Value = lhs[1]
}
}
rang.Def = r.initDefn(rang, names)
rang.X = r.expr()
if rang.X.Type().IsMap() {
rang.RType = r.rtype(pos)
}
if rang.Key != nil && !ir.IsBlank(rang.Key) {
rang.KeyTypeWord, rang.KeySrcRType = r.convRTTI(pos)
}
if rang.Value != nil && !ir.IsBlank(rang.Value) {
rang.ValueTypeWord, rang.ValueSrcRType = r.convRTTI(pos)
}
rang.Body = r.blockStmt()
rang.DistinctVars = r.Bool()
r.closeAnotherScope()
return rang
}
pos := r.pos()
init := r.stmt()
cond := r.optExpr()
post := r.stmt()
body := r.blockStmt()
dv := r.Bool()
r.closeAnotherScope()
stmt := ir.NewForStmt(pos, init, cond, post, body, dv)
stmt.Label = label
return stmt
}
func (r *reader) ifStmt() ir.Node {
r.Sync(pkgbits.SyncIfStmt)
r.openScope()
pos := r.pos()
init := r.stmts()
cond := r.expr()
then := r.blockStmt()
els := r.stmts()
n := ir.NewIfStmt(pos, cond, then, els)
n.SetInit(init)
r.closeAnotherScope()
return n
}
func (r *reader) selectStmt(label *types.Sym) ir.Node {
r.Sync(pkgbits.SyncSelectStmt)
pos := r.pos()
clauses := make([]*ir.CommClause, r.Len())
for i := range clauses {
if i > 0 {
r.closeScope()
}
r.openScope()
pos := r.pos()
comm := r.stmt()
body := r.stmts()
// "case i = <-c: ..." may require an implicit conversion (e.g.,
// see fixedbugs/bug312.go). Currently, typecheck throws away the
// implicit conversion and relies on it being reinserted later,
// but that would lose any explicit RTTI operands too. To preserve
// RTTI, we rewrite this as "case tmp := <-c: i = tmp; ...".
if as, ok := comm.(*ir.AssignStmt); ok && as.Op() == ir.OAS && !as.Def {
if conv, ok := as.Y.(*ir.ConvExpr); ok && conv.Op() == ir.OCONVIFACE {
base.AssertfAt(conv.Implicit(), conv.Pos(), "expected implicit conversion: %v", conv)
recv := conv.X
base.AssertfAt(recv.Op() == ir.ORECV, recv.Pos(), "expected receive expression: %v", recv)
tmp := r.temp(pos, recv.Type())
// Replace comm with `tmp := <-c`.
tmpAs := ir.NewAssignStmt(pos, tmp, recv)
tmpAs.Def = true
tmpAs.PtrInit().Append(ir.NewDecl(pos, ir.ODCL, tmp))
comm = tmpAs
// Change original assignment to `i = tmp`, and prepend to body.
conv.X = tmp
body = append([]ir.Node{as}, body...)
}
}
// multiExpr will have desugared a comma-ok receive expression
// into a separate statement. However, the rest of the compiler
// expects comm to be the OAS2RECV statement itself, so we need to
// shuffle things around to fit that pattern.
if as2, ok := comm.(*ir.AssignListStmt); ok && as2.Op() == ir.OAS2 {
init := ir.TakeInit(as2.Rhs[0])
base.AssertfAt(len(init) == 1 && init[0].Op() == ir.OAS2RECV, as2.Pos(), "unexpected assignment: %+v", as2)
comm = init[0]
body = append([]ir.Node{as2}, body...)
}
clauses[i] = ir.NewCommStmt(pos, comm, body)
}
if len(clauses) > 0 {
r.closeScope()
}
n := ir.NewSelectStmt(pos, clauses)
n.Label = label
return n
}
func (r *reader) switchStmt(label *types.Sym) ir.Node {
r.Sync(pkgbits.SyncSwitchStmt)
r.openScope()
pos := r.pos()
init := r.stmt()
var tag ir.Node
var ident *ir.Ident
var iface *types.Type
if r.Bool() {
pos := r.pos()
if r.Bool() {
pos := r.pos()
_, sym := r.localIdent()
ident = ir.NewIdent(pos, sym)
}
x := r.expr()
iface = x.Type()
tag = ir.NewTypeSwitchGuard(pos, ident, x)
} else {
tag = r.optExpr()
}
clauses := make([]*ir.CaseClause, r.Len())
for i := range clauses {
if i > 0 {
r.closeScope()
}
r.openScope()
pos := r.pos()
var cases, rtypes []ir.Node
if iface != nil {
cases = make([]ir.Node, r.Len())
if len(cases) == 0 {
cases = nil // TODO(mdempsky): Unclear if this matters.
}
for i := range cases {
if r.Bool() { // case nil
cases[i] = typecheck.Expr(types.BuiltinPkg.Lookup("nil").Def.(*ir.NilExpr))
} else {
cases[i] = r.exprType()
}
}
} else {
cases = r.exprList()
// For `switch { case any(true): }` (e.g., issue 3980 in
// test/switch.go), the backend still creates a mixed bool/any
// comparison, and we need to explicitly supply the RTTI for the
// comparison.
//
// TODO(mdempsky): Change writer.go to desugar "switch {" into
// "switch true {", which we already handle correctly.
if tag == nil {
for i, cas := range cases {
if cas.Type().IsEmptyInterface() {
for len(rtypes) < i {
rtypes = append(rtypes, nil)
}
rtypes = append(rtypes, reflectdata.TypePtrAt(cas.Pos(), types.Types[types.TBOOL]))
}
}
}
}
clause := ir.NewCaseStmt(pos, cases, nil)
clause.RTypes = rtypes
if ident != nil {
pos := r.pos()
typ := r.typ()
name := ir.NewNameAt(pos, ident.Sym())
setType(name, typ)
r.addLocal(name, ir.PAUTO)
clause.Var = name
name.Defn = tag
}
clause.Body = r.stmts()
clauses[i] = clause
}
if len(clauses) > 0 {
r.closeScope()
}
r.closeScope()
n := ir.NewSwitchStmt(pos, tag, clauses)
n.Label = label
if init != nil {
n.SetInit([]ir.Node{init})
}
return n
}
func (r *reader) label() *types.Sym {
r.Sync(pkgbits.SyncLabel)
name := r.String()
if r.inlCall != nil {
name = fmt.Sprintf("~%s·%d", name, inlgen)
}
return typecheck.Lookup(name)
}
func (r *reader) optLabel() *types.Sym {
r.Sync(pkgbits.SyncOptLabel)
if r.Bool() {
return r.label()
}
return nil
}
// initDefn marks the given names as declared by defn and populates
// its Init field with ODCL nodes. It then reports whether any names
// were so declared, which can be used to initialize defn.Def.
func (r *reader) initDefn(defn ir.InitNode, names []*ir.Name) bool {
if len(names) == 0 {
return false
}
init := make([]ir.Node, len(names))
for i, name := range names {
name.Defn = defn
init[i] = ir.NewDecl(name.Pos(), ir.ODCL, name)
}
defn.SetInit(init)
return true
}
// @@@ Expressions
// expr reads and returns a typechecked expression.
func (r *reader) expr() (res ir.Node) {
defer func() {
if res != nil && res.Typecheck() == 0 {
base.FatalfAt(res.Pos(), "%v missed typecheck", res)
}
}()
switch tag := codeExpr(r.Code(pkgbits.SyncExpr)); tag {
default:
panic("unhandled expression")
case exprLocal:
return typecheck.Expr(r.useLocal())
case exprGlobal:
// Callee instead of Expr allows builtins
// TODO(mdempsky): Handle builtins directly in exprCall, like method calls?
return typecheck.Callee(r.obj())
case exprFuncInst:
origPos, pos := r.origPos()
wrapperFn, baseFn, dictPtr := r.funcInst(pos)
if wrapperFn != nil {
return wrapperFn
}
return r.curry(origPos, false, baseFn, dictPtr, nil)
case exprConst:
pos := r.pos()
typ := r.typ()
val := FixValue(typ, r.Value())
op := r.op()
orig := r.String()
return typecheck.Expr(OrigConst(pos, typ, val, op, orig))
case exprNil:
pos := r.pos()
typ := r.typ()
return Nil(pos, typ)
case exprCompLit:
return r.compLit()
case exprFuncLit:
return r.funcLit()
case exprFieldVal:
x := r.expr()
pos := r.pos()
_, sym := r.selector()
return typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, x, sym)).(*ir.SelectorExpr)
case exprMethodVal:
recv := r.expr()
origPos, pos := r.origPos()
wrapperFn, baseFn, dictPtr := r.methodExpr()
// For simple wrapperFn values, the existing machinery for creating
// and deduplicating wrapperFn value wrappers still works fine.
if wrapperFn, ok := wrapperFn.(*ir.SelectorExpr); ok && wrapperFn.Op() == ir.OMETHEXPR {
// The receiver expression we constructed may have a shape type.
// For example, in fixedbugs/issue54343.go, `New[int]()` is
// constructed as `New[go.shape.int](&.dict.New[int])`, which
// has type `*T[go.shape.int]`, not `*T[int]`.
//
// However, the method we want to select here is `(*T[int]).M`,
// not `(*T[go.shape.int]).M`, so we need to manually convert
// the type back so that the OXDOT resolves correctly.
//
// TODO(mdempsky): Logically it might make more sense for
// exprCall to take responsibility for setting a non-shaped
// result type, but this is the only place where we care
// currently. And only because existing ir.OMETHVALUE backend
// code relies on n.X.Type() instead of n.Selection.Recv().Type
// (because the latter is types.FakeRecvType() in the case of
// interface method values).
//
if recv.Type().HasShape() {
typ := wrapperFn.Type().Params().Field(0).Type
if !types.Identical(typ, recv.Type()) {
base.FatalfAt(wrapperFn.Pos(), "receiver %L does not match %L", recv, wrapperFn)
}
recv = typecheck.Expr(ir.NewConvExpr(recv.Pos(), ir.OCONVNOP, typ, recv))
}
n := typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, recv, wrapperFn.Sel)).(*ir.SelectorExpr)
// As a consistency check here, we make sure "n" selected the
// same method (represented by a types.Field) that wrapperFn
// selected. However, for anonymous receiver types, there can be
// multiple such types.Field instances (#58563). So we may need
// to fallback to making sure Sym and Type (including the
// receiver parameter's type) match.
if n.Selection != wrapperFn.Selection {
assert(n.Selection.Sym == wrapperFn.Selection.Sym)
assert(types.Identical(n.Selection.Type, wrapperFn.Selection.Type))
assert(types.Identical(n.Selection.Type.Recv().Type, wrapperFn.Selection.Type.Recv().Type))
}
wrapper := methodValueWrapper{
rcvr: n.X.Type(),
method: n.Selection,
}
if r.importedDef() {
haveMethodValueWrappers = append(haveMethodValueWrappers, wrapper)
} else {
needMethodValueWrappers = append(needMethodValueWrappers, wrapper)
}
return n
}
// For more complicated method expressions, we construct a
// function literal wrapper.
return r.curry(origPos, true, baseFn, recv, dictPtr)
case exprMethodExpr:
recv := r.typ()
implicits := make([]int, r.Len())
for i := range implicits {
implicits[i] = r.Len()
}
var deref, addr bool
if r.Bool() {
deref = true
} else if r.Bool() {
addr = true
}
origPos, pos := r.origPos()
wrapperFn, baseFn, dictPtr := r.methodExpr()
// If we already have a wrapper and don't need to do anything with
// it, we can just return the wrapper directly.
//
// N.B., we use implicits/deref/addr here as the source of truth
// rather than types.Identical, because the latter can be confused
// by tricky promoted methods (e.g., typeparam/mdempsky/21.go).
if wrapperFn != nil && len(implicits) == 0 && !deref && !addr {
if !types.Identical(recv, wrapperFn.Type().Params().Field(0).Type) {
base.FatalfAt(pos, "want receiver type %v, but have method %L", recv, wrapperFn)
}
return wrapperFn
}
// Otherwise, if the wrapper function is a static method
// expression (OMETHEXPR) and the receiver type is unshaped, then
// we can rely on a statically generated wrapper being available.
if method, ok := wrapperFn.(*ir.SelectorExpr); ok && method.Op() == ir.OMETHEXPR && !recv.HasShape() {
return typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(recv), method.Sel)).(*ir.SelectorExpr)
}
return r.methodExprWrap(origPos, recv, implicits, deref, addr, baseFn, dictPtr)
case exprIndex:
x := r.expr()
pos := r.pos()
index := r.expr()
n := typecheck.Expr(ir.NewIndexExpr(pos, x, index))
switch n.Op() {
case ir.OINDEXMAP:
n := n.(*ir.IndexExpr)
n.RType = r.rtype(pos)
}
return n
case exprSlice:
x := r.expr()
pos := r.pos()
var index [3]ir.Node
for i := range index {
index[i] = r.optExpr()
}
op := ir.OSLICE
if index[2] != nil {
op = ir.OSLICE3
}
return typecheck.Expr(ir.NewSliceExpr(pos, op, x, index[0], index[1], index[2]))
case exprAssert:
x := r.expr()
pos := r.pos()
typ := r.exprType()
srcRType := r.rtype(pos)
// TODO(mdempsky): Always emit ODYNAMICDOTTYPE for uniformity?
if typ, ok := typ.(*ir.DynamicType); ok && typ.Op() == ir.ODYNAMICTYPE {
assert := ir.NewDynamicTypeAssertExpr(pos, ir.ODYNAMICDOTTYPE, x, typ.RType)
assert.SrcRType = srcRType
assert.ITab = typ.ITab
return typed(typ.Type(), assert)
}
return typecheck.Expr(ir.NewTypeAssertExpr(pos, x, typ.Type()))
case exprUnaryOp:
op := r.op()
pos := r.pos()
x := r.expr()
switch op {
case ir.OADDR:
return typecheck.Expr(typecheck.NodAddrAt(pos, x))
case ir.ODEREF:
return typecheck.Expr(ir.NewStarExpr(pos, x))
}
return typecheck.Expr(ir.NewUnaryExpr(pos, op, x))
case exprBinaryOp:
op := r.op()
x := r.expr()
pos := r.pos()
y := r.expr()
switch op {
case ir.OANDAND, ir.OOROR:
return typecheck.Expr(ir.NewLogicalExpr(pos, op, x, y))
}
return typecheck.Expr(ir.NewBinaryExpr(pos, op, x, y))
case exprRecv:
x := r.expr()
pos := r.pos()
for i, n := 0, r.Len(); i < n; i++ {
x = Implicit(DotField(pos, x, r.Len()))
}
if r.Bool() { // needs deref
x = Implicit(Deref(pos, x.Type().Elem(), x))
} else if r.Bool() { // needs addr
x = Implicit(Addr(pos, x))
}
return x
case exprCall:
var fun ir.Node
var args ir.Nodes
if r.Bool() { // method call
recv := r.expr()
_, method, dictPtr := r.methodExpr()
if recv.Type().IsInterface() && method.Op() == ir.OMETHEXPR {
method := method.(*ir.SelectorExpr)
// The compiler backend (e.g., devirtualization) handle
// OCALLINTER/ODOTINTER better than OCALLFUNC/OMETHEXPR for
// interface calls, so we prefer to continue constructing
// calls that way where possible.
//
// There are also corner cases where semantically it's perhaps
// significant; e.g., fixedbugs/issue15975.go, #38634, #52025.
fun = typecheck.Callee(ir.NewSelectorExpr(method.Pos(), ir.OXDOT, recv, method.Sel))
} else {
if recv.Type().IsInterface() {
// N.B., this happens currently for typeparam/issue51521.go
// and typeparam/typeswitch3.go.
if base.Flag.LowerM != 0 {
base.WarnfAt(method.Pos(), "imprecise interface call")
}
}
fun = method
args.Append(recv)
}
if dictPtr != nil {
args.Append(dictPtr)
}
} else if r.Bool() { // call to instanced function
pos := r.pos()
_, shapedFn, dictPtr := r.funcInst(pos)
fun = shapedFn
args.Append(dictPtr)
} else {
fun = r.expr()
}
pos := r.pos()
args.Append(r.multiExpr()...)
dots := r.Bool()
n := typecheck.Call(pos, fun, args, dots)
switch n.Op() {
case ir.OAPPEND:
n := n.(*ir.CallExpr)
n.RType = r.rtype(pos)
// For append(a, b...), we don't need the implicit conversion. The typechecker already
// ensured that a and b are both slices with the same base type, or []byte and string.
if n.IsDDD {
if conv, ok := n.Args[1].(*ir.ConvExpr); ok && conv.Op() == ir.OCONVNOP && conv.Implicit() {
n.Args[1] = conv.X
}
}
case ir.OCOPY:
n := n.(*ir.BinaryExpr)
n.RType = r.rtype(pos)
case ir.ODELETE:
n := n.(*ir.CallExpr)
n.RType = r.rtype(pos)
case ir.OUNSAFESLICE:
n := n.(*ir.BinaryExpr)
n.RType = r.rtype(pos)
}
return n
case exprMake:
pos := r.pos()
typ := r.exprType()
extra := r.exprs()
n := typecheck.Expr(ir.NewCallExpr(pos, ir.OMAKE, nil, append([]ir.Node{typ}, extra...))).(*ir.MakeExpr)
n.RType = r.rtype(pos)
return n
case exprNew:
pos := r.pos()
typ := r.exprType()
return typecheck.Expr(ir.NewUnaryExpr(pos, ir.ONEW, typ))
case exprReshape:
typ := r.typ()
x := r.expr()
if types.IdenticalStrict(x.Type(), typ) {
return x
}
// Comparison expressions are constructed as "untyped bool" still.
//
// TODO(mdempsky): It should be safe to reshape them here too, but
// maybe it's better to construct them with the proper type
// instead.
if x.Type() == types.UntypedBool && typ.IsBoolean() {
return x
}
base.AssertfAt(x.Type().HasShape() || typ.HasShape(), x.Pos(), "%L and %v are not shape types", x, typ)
base.AssertfAt(types.Identical(x.Type(), typ), x.Pos(), "%L is not shape-identical to %v", x, typ)
// We use ir.HasUniquePos here as a check that x only appears once
// in the AST, so it's okay for us to call SetType without
// breaking any other uses of it.
//
// Notably, any ONAMEs should already have the exactly right shape
// type and been caught by types.IdenticalStrict above.
base.AssertfAt(ir.HasUniquePos(x), x.Pos(), "cannot call SetType(%v) on %L", typ, x)
if base.Debug.Reshape != 0 {
base.WarnfAt(x.Pos(), "reshaping %L to %v", x, typ)
}
x.SetType(typ)
return x
case exprConvert:
implicit := r.Bool()
typ := r.typ()
pos := r.pos()
typeWord, srcRType := r.convRTTI(pos)
dstTypeParam := r.Bool()
identical := r.Bool()
x := r.expr()
// TODO(mdempsky): Stop constructing expressions of untyped type.
x = typecheck.DefaultLit(x, typ)
ce := ir.NewConvExpr(pos, ir.OCONV, typ, x)
ce.TypeWord, ce.SrcRType = typeWord, srcRType
if implicit {
ce.SetImplicit(true)
}
n := typecheck.Expr(ce)
// Conversions between non-identical, non-empty interfaces always
// requires a runtime call, even if they have identical underlying
// interfaces. This is because we create separate itab instances
// for each unique interface type, not merely each unique
// interface shape.
//
// However, due to shape types, typecheck.Expr might mistakenly
// think a conversion between two non-empty interfaces are
// identical and set ir.OCONVNOP, instead of ir.OCONVIFACE. To
// ensure we update the itab field appropriately, we force it to
// ir.OCONVIFACE instead when shape types are involved.
//
// TODO(mdempsky): Are there other places we might get this wrong?
// Should this be moved down into typecheck.{Assign,Convert}op?
// This would be a non-issue if itabs were unique for each
// *underlying* interface type instead.
if !identical {
if n, ok := n.(*ir.ConvExpr); ok && n.Op() == ir.OCONVNOP && n.Type().IsInterface() && !n.Type().IsEmptyInterface() && (n.Type().HasShape() || n.X.Type().HasShape()) {
n.SetOp(ir.OCONVIFACE)
}
}
// spec: "If the type is a type parameter, the constant is converted
// into a non-constant value of the type parameter."
if dstTypeParam && ir.IsConstNode(n) {
// Wrap in an OCONVNOP node to ensure result is non-constant.
n = Implicit(ir.NewConvExpr(pos, ir.OCONVNOP, n.Type(), n))
n.SetTypecheck(1)
}
return n
}
}
// funcInst reads an instantiated function reference, and returns
// three (possibly nil) expressions related to it:
//
// baseFn is always non-nil: it's either a function of the appropriate
// type already, or it has an extra dictionary parameter as the first
// parameter.
//
// If dictPtr is non-nil, then it's a dictionary argument that must be
// passed as the first argument to baseFn.
//
// If wrapperFn is non-nil, then it's either the same as baseFn (if
// dictPtr is nil), or it's semantically equivalent to currying baseFn
// to pass dictPtr. (wrapperFn is nil when dictPtr is an expression
// that needs to be computed dynamically.)
//
// For callers that are creating a call to the returned function, it's
// best to emit a call to baseFn, and include dictPtr in the arguments
// list as appropriate.
//
// For callers that want to return the function without invoking it,
// they may return wrapperFn if it's non-nil; but otherwise, they need
// to create their own wrapper.
func (r *reader) funcInst(pos src.XPos) (wrapperFn, baseFn, dictPtr ir.Node) {
// Like in methodExpr, I'm pretty sure this isn't needed.
var implicits []*types.Type
if r.dict != nil {
implicits = r.dict.targs
}
if r.Bool() { // dynamic subdictionary
idx := r.Len()
info := r.dict.subdicts[idx]
explicits := r.p.typListIdx(info.explicits, r.dict)
baseFn = r.p.objIdx(info.idx, implicits, explicits, true).(*ir.Name)
// TODO(mdempsky): Is there a more robust way to get the
// dictionary pointer type here?
dictPtrType := baseFn.Type().Params().Field(0).Type
dictPtr = typecheck.Expr(ir.NewConvExpr(pos, ir.OCONVNOP, dictPtrType, r.dictWord(pos, r.dict.subdictsOffset()+idx)))
return
}
info := r.objInfo()
explicits := r.p.typListIdx(info.explicits, r.dict)
wrapperFn = r.p.objIdx(info.idx, implicits, explicits, false).(*ir.Name)
baseFn = r.p.objIdx(info.idx, implicits, explicits, true).(*ir.Name)
dictName := r.p.objDictName(info.idx, implicits, explicits)
dictPtr = typecheck.Expr(ir.NewAddrExpr(pos, dictName))
return
}
func (pr *pkgReader) objDictName(idx pkgbits.Index, implicits, explicits []*types.Type) *ir.Name {
rname := pr.newReader(pkgbits.RelocName, idx, pkgbits.SyncObject1)
_, sym := rname.qualifiedIdent()
tag := pkgbits.CodeObj(rname.Code(pkgbits.SyncCodeObj))
if tag == pkgbits.ObjStub {
assert(!sym.IsBlank())
if pri, ok := objReader[sym]; ok {
return pri.pr.objDictName(pri.idx, nil, explicits)
}
base.Fatalf("unresolved stub: %v", sym)
}
dict := pr.objDictIdx(sym, idx, implicits, explicits, false)
return pr.dictNameOf(dict)
}
// curry returns a function literal that calls fun with arg0 and
// (optionally) arg1, accepting additional arguments to the function
// literal as necessary to satisfy fun's signature.
//
// If nilCheck is true and arg0 is an interface value, then it's
// checked to be non-nil as an initial step at the point of evaluating
// the function literal itself.
func (r *reader) curry(origPos src.XPos, ifaceHack bool, fun ir.Node, arg0, arg1 ir.Node) ir.Node {
var captured ir.Nodes
captured.Append(fun, arg0)
if arg1 != nil {
captured.Append(arg1)
}
params, results := syntheticSig(fun.Type())
params = params[len(captured)-1:] // skip curried parameters
typ := types.NewSignature(nil, params, results)
addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
recvs, params := r.syntheticArgs(pos)
assert(len(recvs) == 0)
fun := captured[0]
var args ir.Nodes
args.Append(captured[1:]...)
args.Append(params...)
r.syntheticTailCall(pos, fun, args)
}
return r.syntheticClosure(origPos, typ, ifaceHack, captured, addBody)
}
// methodExprWrap returns a function literal that changes method's
// first parameter's type to recv, and uses implicits/deref/addr to
// select the appropriate receiver parameter to pass to method.
func (r *reader) methodExprWrap(origPos src.XPos, recv *types.Type, implicits []int, deref, addr bool, method, dictPtr ir.Node) ir.Node {
var captured ir.Nodes
captured.Append(method)
params, results := syntheticSig(method.Type())
// Change first parameter to recv.
params[0].Type = recv
// If we have a dictionary pointer argument to pass, then omit the
// underlying method expression's dictionary parameter from the
// returned signature too.
if dictPtr != nil {
captured.Append(dictPtr)
params = append(params[:1], params[2:]...)
}
typ := types.NewSignature(nil, params, results)
addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
recvs, args := r.syntheticArgs(pos)
assert(len(recvs) == 0)
fn := captured[0]
// Rewrite first argument based on implicits/deref/addr.
{
arg := args[0]
for _, ix := range implicits {
arg = Implicit(DotField(pos, arg, ix))
}
if deref {
arg = Implicit(Deref(pos, arg.Type().Elem(), arg))
} else if addr {
arg = Implicit(Addr(pos, arg))
}
args[0] = arg
}
// Insert dictionary argument, if provided.
if dictPtr != nil {
newArgs := make([]ir.Node, len(args)+1)
newArgs[0] = args[0]
newArgs[1] = captured[1]
copy(newArgs[2:], args[1:])
args = newArgs
}
r.syntheticTailCall(pos, fn, args)
}
return r.syntheticClosure(origPos, typ, false, captured, addBody)
}
// syntheticClosure constructs a synthetic function literal for
// currying dictionary arguments. origPos is the position used for the
// closure, which must be a non-inlined position. typ is the function
// literal's signature type.
//
// captures is a list of expressions that need to be evaluated at the
// point of function literal evaluation and captured by the function
// literal. If ifaceHack is true and captures[1] is an interface type,
// it's checked to be non-nil after evaluation.
//
// addBody is a callback function to populate the function body. The
// list of captured values passed back has the captured variables for
// use within the function literal, corresponding to the expressions
// in captures.
func (r *reader) syntheticClosure(origPos src.XPos, typ *types.Type, ifaceHack bool, captures ir.Nodes, addBody func(pos src.XPos, r *reader, captured []ir.Node)) ir.Node {
// isSafe reports whether n is an expression that we can safely
// defer to evaluating inside the closure instead, to avoid storing
// them into the closure.
//
// In practice this is always (and only) the wrappee function.
isSafe := func(n ir.Node) bool {
if n.Op() == ir.ONAME && n.(*ir.Name).Class == ir.PFUNC {
return true
}
if n.Op() == ir.OMETHEXPR {
return true
}
return false
}
// The ODCLFUNC and its body need to use the original position, but
// the OCLOSURE node and any Init statements should use the inlined
// position instead. See also the explanation in reader.funcLit.
inlPos := r.inlPos(origPos)
fn := ir.NewClosureFunc(origPos, r.curfn != nil)
fn.SetWrapper(true)
clo := fn.OClosure
clo.SetPos(inlPos)
ir.NameClosure(clo, r.curfn)
setType(fn.Nname, typ)
typecheck.Func(fn)
setType(clo, fn.Type())
var init ir.Nodes
for i, n := range captures {
if isSafe(n) {
continue // skip capture; can reference directly
}
tmp := r.tempCopy(inlPos, n, &init)
ir.NewClosureVar(origPos, fn, tmp)
// We need to nil check interface receivers at the point of method
// value evaluation, ugh.
if ifaceHack && i == 1 && n.Type().IsInterface() {
check := ir.NewUnaryExpr(inlPos, ir.OCHECKNIL, ir.NewUnaryExpr(inlPos, ir.OITAB, tmp))
init.Append(typecheck.Stmt(check))
}
}
pri := pkgReaderIndex{synthetic: func(pos src.XPos, r *reader) {
captured := make([]ir.Node, len(captures))
next := 0
for i, n := range captures {
if isSafe(n) {
captured[i] = n
} else {
captured[i] = r.closureVars[next]
next++
}
}
assert(next == len(r.closureVars))
addBody(origPos, r, captured)
}}
bodyReader[fn] = pri
pri.funcBody(fn)
// TODO(mdempsky): Remove hard-coding of typecheck.Target.
return ir.InitExpr(init, ir.UseClosure(clo, typecheck.Target))
}
// syntheticSig duplicates and returns the params and results lists
// for sig, but renaming anonymous parameters so they can be assigned
// ir.Names.
func syntheticSig(sig *types.Type) (params, results []*types.Field) {
clone := func(params []*types.Field) []*types.Field {
res := make([]*types.Field, len(params))
for i, param := range params {
sym := param.Sym
if sym == nil || sym.Name == "_" {
sym = typecheck.LookupNum(".anon", i)
}
// TODO(mdempsky): It would be nice to preserve the original
// parameter positions here instead, but at least
// typecheck.NewMethodType replaces them with base.Pos, making
// them useless. Worse, the positions copied from base.Pos may
// have inlining contexts, which we definitely don't want here
// (e.g., #54625).
res[i] = types.NewField(base.AutogeneratedPos, sym, param.Type)
res[i].SetIsDDD(param.IsDDD())
}
return res
}
return clone(sig.Params().FieldSlice()), clone(sig.Results().FieldSlice())
}
func (r *reader) optExpr() ir.Node {
if r.Bool() {
return r.expr()
}
return nil
}
// methodExpr reads a method expression reference, and returns three
// (possibly nil) expressions related to it:
//
// baseFn is always non-nil: it's either a function of the appropriate
// type already, or it has an extra dictionary parameter as the second
// parameter (i.e., immediately after the promoted receiver
// parameter).
//
// If dictPtr is non-nil, then it's a dictionary argument that must be
// passed as the second argument to baseFn.
//
// If wrapperFn is non-nil, then it's either the same as baseFn (if
// dictPtr is nil), or it's semantically equivalent to currying baseFn
// to pass dictPtr. (wrapperFn is nil when dictPtr is an expression
// that needs to be computed dynamically.)
//
// For callers that are creating a call to the returned method, it's
// best to emit a call to baseFn, and include dictPtr in the arguments
// list as appropriate.
//
// For callers that want to return a method expression without
// invoking it, they may return wrapperFn if it's non-nil; but
// otherwise, they need to create their own wrapper.
func (r *reader) methodExpr() (wrapperFn, baseFn, dictPtr ir.Node) {
recv := r.typ()
sig0 := r.typ()
pos := r.pos()
_, sym := r.selector()
// Signature type to return (i.e., recv prepended to the method's
// normal parameters list).
sig := typecheck.NewMethodType(sig0, recv)
if r.Bool() { // type parameter method expression
idx := r.Len()
word := r.dictWord(pos, r.dict.typeParamMethodExprsOffset()+idx)
// TODO(mdempsky): If the type parameter was instantiated with an
// interface type (i.e., embed.IsInterface()), then we could
// return the OMETHEXPR instead and save an indirection.
// We wrote the method expression's entry point PC into the
// dictionary, but for Go `func` values we need to return a
// closure (i.e., pointer to a structure with the PC as the first
// field). Because method expressions don't have any closure
// variables, we pun the dictionary entry as the closure struct.
fn := typecheck.Expr(ir.NewConvExpr(pos, ir.OCONVNOP, sig, ir.NewAddrExpr(pos, word)))
return fn, fn, nil
}
// TODO(mdempsky): I'm pretty sure this isn't needed: implicits is
// only relevant to locally defined types, but they can't have
// (non-promoted) methods.
var implicits []*types.Type
if r.dict != nil {
implicits = r.dict.targs
}
if r.Bool() { // dynamic subdictionary
idx := r.Len()
info := r.dict.subdicts[idx]
explicits := r.p.typListIdx(info.explicits, r.dict)
shapedObj := r.p.objIdx(info.idx, implicits, explicits, true).(*ir.Name)
shapedFn := shapedMethodExpr(pos, shapedObj, sym)
// TODO(mdempsky): Is there a more robust way to get the
// dictionary pointer type here?
dictPtrType := shapedFn.Type().Params().Field(1).Type
dictPtr := typecheck.Expr(ir.NewConvExpr(pos, ir.OCONVNOP, dictPtrType, r.dictWord(pos, r.dict.subdictsOffset()+idx)))
return nil, shapedFn, dictPtr
}
if r.Bool() { // static dictionary
info := r.objInfo()
explicits := r.p.typListIdx(info.explicits, r.dict)
shapedObj := r.p.objIdx(info.idx, implicits, explicits, true).(*ir.Name)
shapedFn := shapedMethodExpr(pos, shapedObj, sym)
dict := r.p.objDictName(info.idx, implicits, explicits)
dictPtr := typecheck.Expr(ir.NewAddrExpr(pos, dict))
// Check that dictPtr matches shapedFn's dictionary parameter.
if !types.Identical(dictPtr.Type(), shapedFn.Type().Params().Field(1).Type) {
base.FatalfAt(pos, "dict %L, but shaped method %L", dict, shapedFn)
}
// For statically known instantiations, we can take advantage of
// the stenciled wrapper.
base.AssertfAt(!recv.HasShape(), pos, "shaped receiver %v", recv)
wrapperFn := typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(recv), sym)).(*ir.SelectorExpr)
base.AssertfAt(types.Identical(sig, wrapperFn.Type()), pos, "wrapper %L does not have type %v", wrapperFn, sig)
return wrapperFn, shapedFn, dictPtr
}
// Simple method expression; no dictionary needed.
base.AssertfAt(!recv.HasShape() || recv.IsInterface(), pos, "shaped receiver %v", recv)
fn := typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(recv), sym)).(*ir.SelectorExpr)
return fn, fn, nil
}
// shapedMethodExpr returns the specified method on the given shaped
// type.
func shapedMethodExpr(pos src.XPos, obj *ir.Name, sym *types.Sym) *ir.SelectorExpr {
assert(obj.Op() == ir.OTYPE)
typ := obj.Type()
assert(typ.HasShape())
method := func() *types.Field {
for _, method := range typ.Methods().Slice() {
if method.Sym == sym {
return method
}
}
base.FatalfAt(pos, "failed to find method %v in shaped type %v", sym, typ)
panic("unreachable")
}()
// Construct an OMETHEXPR node.
recv := method.Type.Recv().Type
return typecheck.Expr(ir.NewSelectorExpr(pos, ir.OXDOT, ir.TypeNode(recv), sym)).(*ir.SelectorExpr)
}
func (r *reader) multiExpr() []ir.Node {
r.Sync(pkgbits.SyncMultiExpr)
if r.Bool() { // N:1
pos := r.pos()
expr := r.expr()
results := make([]ir.Node, r.Len())
as := ir.NewAssignListStmt(pos, ir.OAS2, nil, []ir.Node{expr})
as.Def = true
for i := range results {
tmp := r.temp(pos, r.typ())
as.PtrInit().Append(ir.NewDecl(pos, ir.ODCL, tmp))
as.Lhs.Append(tmp)
res := ir.Node(tmp)
if r.Bool() {
n := ir.NewConvExpr(pos, ir.OCONV, r.typ(), res)
n.TypeWord, n.SrcRType = r.convRTTI(pos)
n.SetImplicit(true)
res = typecheck.Expr(n)
}
results[i] = res
}
// TODO(mdempsky): Could use ir.InlinedCallExpr instead?
results[0] = ir.InitExpr([]ir.Node{typecheck.Stmt(as)}, results[0])
return results
}
// N:N
exprs := make([]ir.Node, r.Len())
if len(exprs) == 0 {
return nil
}
for i := range exprs {
exprs[i] = r.expr()
}
return exprs
}
// temp returns a new autotemp of the specified type.
func (r *reader) temp(pos src.XPos, typ *types.Type) *ir.Name {
// See typecheck.typecheckargs.
curfn := r.curfn
if curfn == nil {
curfn = typecheck.InitTodoFunc
}
return typecheck.TempAt(pos, curfn, typ)
}
// tempCopy declares and returns a new autotemp initialized to the
// value of expr.
func (r *reader) tempCopy(pos src.XPos, expr ir.Node, init *ir.Nodes) *ir.Name {
if r.curfn == nil {
// Escape analysis doesn't know how to handle package-scope
// function literals with free variables (i.e., that capture
// temporary variables added to typecheck.InitTodoFunc).
//
// stencil.go works around this limitation by spilling values to
// global variables instead, but that causes the value to stay
// alive indefinitely; see go.dev/issue/54343.
//
// This code path (which implements the same workaround) isn't
// actually needed by unified IR, because it creates uses normal
// OMETHEXPR/OMETHVALUE nodes when statically-known instantiated
// types are used. But it's kept around for now because it's handy
// for testing that the generic fallback paths work correctly.
base.Fatalf("tempCopy called at package scope")
tmp := staticinit.StaticName(expr.Type())
assign := ir.NewAssignStmt(pos, tmp, expr)
assign.Def = true
tmp.Defn = assign
typecheck.Target.Decls = append(typecheck.Target.Decls, typecheck.Stmt(assign))
return tmp
}
tmp := r.temp(pos, expr.Type())
init.Append(typecheck.Stmt(ir.NewDecl(pos, ir.ODCL, tmp)))
assign := ir.NewAssignStmt(pos, tmp, expr)
assign.Def = true
init.Append(typecheck.Stmt(ir.NewAssignStmt(pos, tmp, expr)))
tmp.Defn = assign
return tmp
}
func (r *reader) compLit() ir.Node {
r.Sync(pkgbits.SyncCompLit)
pos := r.pos()
typ0 := r.typ()
typ := typ0
if typ.IsPtr() {
typ = typ.Elem()
}
if typ.Kind() == types.TFORW {
base.FatalfAt(pos, "unresolved composite literal type: %v", typ)
}
var rtype ir.Node
if typ.IsMap() {
rtype = r.rtype(pos)
}
isStruct := typ.Kind() == types.TSTRUCT
elems := make([]ir.Node, r.Len())
for i := range elems {
elemp := &elems[i]
if isStruct {
sk := ir.NewStructKeyExpr(r.pos(), typ.Field(r.Len()), nil)
*elemp, elemp = sk, &sk.Value
} else if r.Bool() {
kv := ir.NewKeyExpr(r.pos(), r.expr(), nil)
*elemp, elemp = kv, &kv.Value
}
*elemp = wrapName(r.pos(), r.expr())
}
lit := typecheck.Expr(ir.NewCompLitExpr(pos, ir.OCOMPLIT, typ, elems))
if rtype != nil {
lit := lit.(*ir.CompLitExpr)
lit.RType = rtype
}
if typ0.IsPtr() {
lit = typecheck.Expr(typecheck.NodAddrAt(pos, lit))
lit.SetType(typ0)
}
return lit
}
func wrapName(pos src.XPos, x ir.Node) ir.Node {
// These nodes do not carry line numbers.
// Introduce a wrapper node to give them the correct line.
switch ir.Orig(x).Op() {
case ir.OTYPE, ir.OLITERAL:
if x.Sym() == nil {
break
}
fallthrough
case ir.ONAME, ir.ONONAME, ir.ONIL:
p := ir.NewParenExpr(pos, x)
p.SetImplicit(true)
return p
}
return x
}
func (r *reader) funcLit() ir.Node {
r.Sync(pkgbits.SyncFuncLit)
// The underlying function declaration (including its parameters'
// positions, if any) need to remain the original, uninlined
// positions. This is because we track inlining-context on nodes so
// we can synthesize the extra implied stack frames dynamically when
// generating tracebacks, whereas those stack frames don't make
// sense *within* the function literal. (Any necessary inlining
// adjustments will have been applied to the call expression
// instead.)
//
// This is subtle, and getting it wrong leads to cycles in the
// inlining tree, which lead to infinite loops during stack
// unwinding (#46234, #54625).
//
// Note that we *do* want the inline-adjusted position for the
// OCLOSURE node, because that position represents where any heap
// allocation of the closure is credited (#49171).
r.suppressInlPos++
pos := r.pos()
xtype2 := r.signature(nil)
r.suppressInlPos--
fn := ir.NewClosureFunc(pos, r.curfn != nil)
clo := fn.OClosure
clo.SetPos(r.inlPos(pos)) // see comment above
ir.NameClosure(clo, r.curfn)
setType(fn.Nname, xtype2)
typecheck.Func(fn)
setType(clo, fn.Type())
fn.ClosureVars = make([]*ir.Name, 0, r.Len())
for len(fn.ClosureVars) < cap(fn.ClosureVars) {
ir.NewClosureVar(r.pos(), fn, r.useLocal())
}
if param := r.dictParam; param != nil {
// If we have a dictionary parameter, capture it too. For
// simplicity, we capture it last and unconditionally.
ir.NewClosureVar(param.Pos(), fn, param)
}
r.addBody(fn, nil)
// TODO(mdempsky): Remove hard-coding of typecheck.Target.
return ir.UseClosure(clo, typecheck.Target)
}
func (r *reader) exprList() []ir.Node {
r.Sync(pkgbits.SyncExprList)
return r.exprs()
}
func (r *reader) exprs() []ir.Node {
r.Sync(pkgbits.SyncExprs)
nodes := make([]ir.Node, r.Len())
if len(nodes) == 0 {
return nil // TODO(mdempsky): Unclear if this matters.
}
for i := range nodes {
nodes[i] = r.expr()
}
return nodes
}
// dictWord returns an expression to return the specified
// uintptr-typed word from the dictionary parameter.
func (r *reader) dictWord(pos src.XPos, idx int) ir.Node {
base.AssertfAt(r.dictParam != nil, pos, "expected dictParam in %v", r.curfn)
return typecheck.Expr(ir.NewIndexExpr(pos, r.dictParam, ir.NewBasicLit(pos, constant.MakeInt64(int64(idx)))))
}
// rttiWord is like dictWord, but converts it to *byte (the type used
// internally to represent *runtime._type and *runtime.itab).
func (r *reader) rttiWord(pos src.XPos, idx int) ir.Node {
return typecheck.Expr(ir.NewConvExpr(pos, ir.OCONVNOP, types.NewPtr(types.Types[types.TUINT8]), r.dictWord(pos, idx)))
}
// rtype reads a type reference from the element bitstream, and
// returns an expression of type *runtime._type representing that
// type.
func (r *reader) rtype(pos src.XPos) ir.Node {
_, rtype := r.rtype0(pos)
return rtype
}
func (r *reader) rtype0(pos src.XPos) (typ *types.Type, rtype ir.Node) {
r.Sync(pkgbits.SyncRType)
if r.Bool() { // derived type
idx := r.Len()
info := r.dict.rtypes[idx]
typ = r.p.typIdx(info, r.dict, true)
rtype = r.rttiWord(pos, r.dict.rtypesOffset()+idx)
return
}
typ = r.typ()
rtype = reflectdata.TypePtrAt(pos, typ)
return
}
// varDictIndex populates name.DictIndex if name is a derived type.
func (r *reader) varDictIndex(name *ir.Name) {
if r.Bool() {
idx := 1 + r.dict.rtypesOffset() + r.Len()
if int(uint16(idx)) != idx {
base.FatalfAt(name.Pos(), "DictIndex overflow for %v: %v", name, idx)
}
name.DictIndex = uint16(idx)
}
}
// itab returns a (typ, iface) pair of types.
//
// typRType and ifaceRType are expressions that evaluate to the
// *runtime._type for typ and iface, respectively.
//
// If typ is a concrete type and iface is a non-empty interface type,
// then itab is an expression that evaluates to the *runtime.itab for
// the pair. Otherwise, itab is nil.
func (r *reader) itab(pos src.XPos) (typ *types.Type, typRType ir.Node, iface *types.Type, ifaceRType ir.Node, itab ir.Node) {
typ, typRType = r.rtype0(pos)
iface, ifaceRType = r.rtype0(pos)
idx := -1
if r.Bool() {
idx = r.Len()
}
if !typ.IsInterface() && iface.IsInterface() && !iface.IsEmptyInterface() {
if idx >= 0 {
itab = r.rttiWord(pos, r.dict.itabsOffset()+idx)
} else {
base.AssertfAt(!typ.HasShape(), pos, "%v is a shape type", typ)
base.AssertfAt(!iface.HasShape(), pos, "%v is a shape type", iface)
lsym := reflectdata.ITabLsym(typ, iface)
itab = typecheck.LinksymAddr(pos, lsym, types.Types[types.TUINT8])
}
}
return
}
// convRTTI returns expressions appropriate for populating an
// ir.ConvExpr's TypeWord and SrcRType fields, respectively.
func (r *reader) convRTTI(pos src.XPos) (typeWord, srcRType ir.Node) {
r.Sync(pkgbits.SyncConvRTTI)
src, srcRType0, dst, dstRType, itab := r.itab(pos)
if !dst.IsInterface() {
return
}
// See reflectdata.ConvIfaceTypeWord.
switch {
case dst.IsEmptyInterface():
if !src.IsInterface() {
typeWord = srcRType0 // direct eface construction
}
case !src.IsInterface():
typeWord = itab // direct iface construction
default:
typeWord = dstRType // convI2I
}
// See reflectdata.ConvIfaceSrcRType.
if !src.IsInterface() {
srcRType = srcRType0
}
return
}
func (r *reader) exprType() ir.Node {
r.Sync(pkgbits.SyncExprType)
pos := r.pos()
var typ *types.Type
var rtype, itab ir.Node
if r.Bool() {
typ, rtype, _, _, itab = r.itab(pos)
if !typ.IsInterface() {
rtype = nil // TODO(mdempsky): Leave set?
}
} else {
typ, rtype = r.rtype0(pos)
if !r.Bool() { // not derived
// TODO(mdempsky): ir.TypeNode should probably return a typecheck'd node.
n := ir.TypeNode(typ)
n.SetTypecheck(1)
return n
}
}
dt := ir.NewDynamicType(pos, rtype)
dt.ITab = itab
return typed(typ, dt)
}
func (r *reader) op() ir.Op {
r.Sync(pkgbits.SyncOp)
return ir.Op(r.Len())
}
// @@@ Package initialization
func (r *reader) pkgInit(self *types.Pkg, target *ir.Package) {
cgoPragmas := make([][]string, r.Len())
for i := range cgoPragmas {
cgoPragmas[i] = r.Strings()
}
target.CgoPragmas = cgoPragmas
r.pkgDecls(target)
r.Sync(pkgbits.SyncEOF)
}
func (r *reader) pkgDecls(target *ir.Package) {
r.Sync(pkgbits.SyncDecls)
for {
switch code := codeDecl(r.Code(pkgbits.SyncDecl)); code {
default:
panic(fmt.Sprintf("unhandled decl: %v", code))
case declEnd:
return
case declFunc:
names := r.pkgObjs(target)
assert(len(names) == 1)
target.Decls = append(target.Decls, names[0].Func)
case declMethod:
typ := r.typ()
_, sym := r.selector()
method := typecheck.Lookdot1(nil, sym, typ, typ.Methods(), 0)
target.Decls = append(target.Decls, method.Nname.(*ir.Name).Func)
case declVar:
pos := r.pos()
names := r.pkgObjs(target)
values := r.exprList()
if len(names) > 1 && len(values) == 1 {
as := ir.NewAssignListStmt(pos, ir.OAS2, nil, values)
for _, name := range names {
as.Lhs.Append(name)
name.Defn = as
}
target.Decls = append(target.Decls, as)
} else {
for i, name := range names {
as := ir.NewAssignStmt(pos, name, nil)
if i < len(values) {
as.Y = values[i]
}
name.Defn = as
target.Decls = append(target.Decls, as)
}
}
if n := r.Len(); n > 0 {
assert(len(names) == 1)
embeds := make([]ir.Embed, n)
for i := range embeds {
embeds[i] = ir.Embed{Pos: r.pos(), Patterns: r.Strings()}
}
names[0].Embed = &embeds
target.Embeds = append(target.Embeds, names[0])
}
case declOther:
r.pkgObjs(target)
}
}
}
func (r *reader) pkgObjs(target *ir.Package) []*ir.Name {
r.Sync(pkgbits.SyncDeclNames)
nodes := make([]*ir.Name, r.Len())
for i := range nodes {
r.Sync(pkgbits.SyncDeclName)
name := r.obj().(*ir.Name)
nodes[i] = name
sym := name.Sym()
if sym.IsBlank() {
continue
}
switch name.Class {
default:
base.FatalfAt(name.Pos(), "unexpected class: %v", name.Class)
case ir.PEXTERN:
target.Externs = append(target.Externs, name)
case ir.PFUNC:
assert(name.Type().Recv() == nil)
// TODO(mdempsky): Cleaner way to recognize init?
if strings.HasPrefix(sym.Name, "init.") {
target.Inits = append(target.Inits, name.Func)
}
}
if types.IsExported(sym.Name) {
assert(!sym.OnExportList())
target.Exports = append(target.Exports, name)
sym.SetOnExportList(true)
}
if base.Flag.AsmHdr != "" {
assert(!sym.Asm())
target.Asms = append(target.Asms, name)
sym.SetAsm(true)
}
}
return nodes
}
// @@@ Inlining
// unifiedHaveInlineBody reports whether we have the function body for
// fn, so we can inline it.
func unifiedHaveInlineBody(fn *ir.Func) bool {
if fn.Inl == nil {
return false
}
_, ok := bodyReaderFor(fn)
return ok
}
var inlgen = 0
// unifiedInlineCall implements inline.NewInline by re-reading the function
// body from its Unified IR export data.
func unifiedInlineCall(call *ir.CallExpr, fn *ir.Func, inlIndex int) *ir.InlinedCallExpr {
// TODO(mdempsky): Turn callerfn into an explicit parameter.
callerfn := ir.CurFunc
pri, ok := bodyReaderFor(fn)
if !ok {
base.FatalfAt(call.Pos(), "cannot inline call to %v: missing inline body", fn)
}
if fn.Inl.Body == nil {
expandInline(fn, pri)
}
r := pri.asReader(pkgbits.RelocBody, pkgbits.SyncFuncBody)
// TODO(mdempsky): This still feels clumsy. Can we do better?
tmpfn := ir.NewFunc(fn.Pos())
tmpfn.Nname = ir.NewNameAt(fn.Nname.Pos(), callerfn.Sym())
tmpfn.Closgen = callerfn.Closgen
defer func() { callerfn.Closgen = tmpfn.Closgen }()
setType(tmpfn.Nname, fn.Type())
r.curfn = tmpfn
r.inlCaller = callerfn
r.inlCall = call
r.inlFunc = fn
r.inlTreeIndex = inlIndex
r.inlPosBases = make(map[*src.PosBase]*src.PosBase)
r.closureVars = make([]*ir.Name, len(r.inlFunc.ClosureVars))
for i, cv := range r.inlFunc.ClosureVars {
r.closureVars[i] = cv.Outer
}
if len(r.closureVars) != 0 && r.hasTypeParams() {
r.dictParam = r.closureVars[len(r.closureVars)-1] // dictParam is last; see reader.funcLit
}
r.funcargs(fn)
r.delayResults = fn.Inl.CanDelayResults
r.retlabel = typecheck.AutoLabel(".i")
inlgen++
init := ir.TakeInit(call)
// For normal function calls, the function callee expression
// may contain side effects. Make sure to preserve these,
// if necessary (#42703).
if call.Op() == ir.OCALLFUNC {
inline.CalleeEffects(&init, call.X)
}
var args ir.Nodes
if call.Op() == ir.OCALLMETH {
base.FatalfAt(call.Pos(), "OCALLMETH missed by typecheck")
}
args.Append(call.Args...)
// Create assignment to declare and initialize inlvars.
as2 := ir.NewAssignListStmt(call.Pos(), ir.OAS2, r.inlvars, args)
as2.Def = true
var as2init ir.Nodes
for _, name := range r.inlvars {
if ir.IsBlank(name) {
continue
}
// TODO(mdempsky): Use inlined position of name.Pos() instead?
name := name.(*ir.Name)
as2init.Append(ir.NewDecl(call.Pos(), ir.ODCL, name))
name.Defn = as2
}
as2.SetInit(as2init)
init.Append(typecheck.Stmt(as2))
if !r.delayResults {
// If not delaying retvars, declare and zero initialize the
// result variables now.
for _, name := range r.retvars {
// TODO(mdempsky): Use inlined position of name.Pos() instead?
name := name.(*ir.Name)
init.Append(ir.NewDecl(call.Pos(), ir.ODCL, name))
ras := ir.NewAssignStmt(call.Pos(), name, nil)
init.Append(typecheck.Stmt(ras))
}
}
// Add an inline mark just before the inlined body.
// This mark is inline in the code so that it's a reasonable spot
// to put a breakpoint. Not sure if that's really necessary or not
// (in which case it could go at the end of the function instead).
// Note issue 28603.
init.Append(ir.NewInlineMarkStmt(call.Pos().WithIsStmt(), int64(r.inlTreeIndex)))
nparams := len(r.curfn.Dcl)
ir.WithFunc(r.curfn, func() {
if !r.syntheticBody(call.Pos()) {
assert(r.Bool()) // have body
r.curfn.Body = r.stmts()
r.curfn.Endlineno = r.pos()
}
// TODO(mdempsky): This shouldn't be necessary. Inlining might
// read in new function/method declarations, which could
// potentially be recursively inlined themselves; but we shouldn't
// need to read in the non-inlined bodies for the declarations
// themselves. But currently it's an easy fix to #50552.
readBodies(typecheck.Target, true)
deadcode.Func(r.curfn)
// Replace any "return" statements within the function body.
var edit func(ir.Node) ir.Node
edit = func(n ir.Node) ir.Node {
if ret, ok := n.(*ir.ReturnStmt); ok {
n = typecheck.Stmt(r.inlReturn(ret))
}
ir.EditChildren(n, edit)
return n
}
edit(r.curfn)
})
body := ir.Nodes(r.curfn.Body)
// Quirkish: We need to eagerly prune variables added during
// inlining, but removed by deadcode.FuncBody above. Unused
// variables will get removed during stack frame layout anyway, but
// len(fn.Dcl) ends up influencing things like autotmp naming.
used := usedLocals(body)
for i, name := range r.curfn.Dcl {
if i < nparams || used.Has(name) {
name.Curfn = callerfn
callerfn.Dcl = append(callerfn.Dcl, name)
if name.AutoTemp() {
name.SetEsc(ir.EscUnknown)
name.SetInlLocal(true)
}
}
}
body.Append(ir.NewLabelStmt(call.Pos(), r.retlabel))
res := ir.NewInlinedCallExpr(call.Pos(), body, append([]ir.Node(nil), r.retvars...))
res.SetInit(init)
res.SetType(call.Type())
res.SetTypecheck(1)
// Inlining shouldn't add any functions to todoBodies.
assert(len(todoBodies) == 0)
return res
}
// inlReturn returns a statement that can substitute for the given
// return statement when inlining.
func (r *reader) inlReturn(ret *ir.ReturnStmt) *ir.BlockStmt {
pos := r.inlCall.Pos()
block := ir.TakeInit(ret)
if results := ret.Results; len(results) != 0 {
assert(len(r.retvars) == len(results))
as2 := ir.NewAssignListStmt(pos, ir.OAS2, append([]ir.Node(nil), r.retvars...), ret.Results)
if r.delayResults {
for _, name := range r.retvars {
// TODO(mdempsky): Use inlined position of name.Pos() instead?
name := name.(*ir.Name)
block.Append(ir.NewDecl(pos, ir.ODCL, name))
name.Defn = as2
}
}
block.Append(as2)
}
block.Append(ir.NewBranchStmt(pos, ir.OGOTO, r.retlabel))
return ir.NewBlockStmt(pos, block)
}
// expandInline reads in an extra copy of IR to populate
// fn.Inl.{Dcl,Body}.
func expandInline(fn *ir.Func, pri pkgReaderIndex) {
// TODO(mdempsky): Remove this function. It's currently needed by
// dwarfgen/dwarf.go:preInliningDcls, which requires fn.Inl.Dcl to
// create abstract function DIEs. But we should be able to provide it
// with the same information some other way.
fndcls := len(fn.Dcl)
topdcls := len(typecheck.Target.Decls)
tmpfn := ir.NewFunc(fn.Pos())
tmpfn.Nname = ir.NewNameAt(fn.Nname.Pos(), fn.Sym())
tmpfn.ClosureVars = fn.ClosureVars
{
r := pri.asReader(pkgbits.RelocBody, pkgbits.SyncFuncBody)
setType(tmpfn.Nname, fn.Type())
// Don't change parameter's Sym/Nname fields.
r.funarghack = true
r.funcBody(tmpfn)
ir.WithFunc(tmpfn, func() {
deadcode.Func(tmpfn)
})
}
used := usedLocals(tmpfn.Body)
for _, name := range tmpfn.Dcl {
if name.Class != ir.PAUTO || used.Has(name) {
name.Curfn = fn
fn.Inl.Dcl = append(fn.Inl.Dcl, name)
}
}
fn.Inl.Body = tmpfn.Body
// Double check that we didn't change fn.Dcl by accident.
assert(fndcls == len(fn.Dcl))
// typecheck.Stmts may have added function literals to
// typecheck.Target.Decls. Remove them again so we don't risk trying
// to compile them multiple times.
typecheck.Target.Decls = typecheck.Target.Decls[:topdcls]
}
// usedLocals returns a set of local variables that are used within body.
func usedLocals(body []ir.Node) ir.NameSet {
var used ir.NameSet
ir.VisitList(body, func(n ir.Node) {
if n, ok := n.(*ir.Name); ok && n.Op() == ir.ONAME && n.Class == ir.PAUTO {
used.Add(n)
}
})
return used
}
// @@@ Method wrappers
// needWrapperTypes lists types for which we may need to generate
// method wrappers.
var needWrapperTypes []*types.Type
// haveWrapperTypes lists types for which we know we already have
// method wrappers, because we found the type in an imported package.
var haveWrapperTypes []*types.Type
// needMethodValueWrappers lists methods for which we may need to
// generate method value wrappers.
var needMethodValueWrappers []methodValueWrapper
// haveMethodValueWrappers lists methods for which we know we already
// have method value wrappers, because we found it in an imported
// package.
var haveMethodValueWrappers []methodValueWrapper
type methodValueWrapper struct {
rcvr *types.Type
method *types.Field
}
func (r *reader) needWrapper(typ *types.Type) {
if typ.IsPtr() {
return
}
// If a type was found in an imported package, then we can assume
// that package (or one of its transitive dependencies) already
// generated method wrappers for it.
if r.importedDef() {
haveWrapperTypes = append(haveWrapperTypes, typ)
} else {
needWrapperTypes = append(needWrapperTypes, typ)
}
}
// importedDef reports whether r is reading from an imported and
// non-generic element.
//
// If a type was found in an imported package, then we can assume that
// package (or one of its transitive dependencies) already generated
// method wrappers for it.
//
// Exception: If we're instantiating an imported generic type or
// function, we might be instantiating it with type arguments not
// previously seen before.
//
// TODO(mdempsky): Distinguish when a generic function or type was
// instantiated in an imported package so that we can add types to
// haveWrapperTypes instead.
func (r *reader) importedDef() bool {
return r.p != localPkgReader && !r.hasTypeParams()
}
func MakeWrappers(target *ir.Package) {
// always generate a wrapper for error.Error (#29304)
needWrapperTypes = append(needWrapperTypes, types.ErrorType)
seen := make(map[string]*types.Type)
for _, typ := range haveWrapperTypes {
wrapType(typ, target, seen, false)
}
haveWrapperTypes = nil
for _, typ := range needWrapperTypes {
wrapType(typ, target, seen, true)
}
needWrapperTypes = nil
for _, wrapper := range haveMethodValueWrappers {
wrapMethodValue(wrapper.rcvr, wrapper.method, target, false)
}
haveMethodValueWrappers = nil
for _, wrapper := range needMethodValueWrappers {
wrapMethodValue(wrapper.rcvr, wrapper.method, target, true)
}
needMethodValueWrappers = nil
}
func wrapType(typ *types.Type, target *ir.Package, seen map[string]*types.Type, needed bool) {
key := typ.LinkString()
if prev := seen[key]; prev != nil {
if !types.Identical(typ, prev) {
base.Fatalf("collision: types %v and %v have link string %q", typ, prev, key)
}
return
}
seen[key] = typ
if !needed {
// Only called to add to 'seen'.
return
}
if !typ.IsInterface() {
typecheck.CalcMethods(typ)
}
for _, meth := range typ.AllMethods().Slice() {
if meth.Sym.IsBlank() || !meth.IsMethod() {
base.FatalfAt(meth.Pos, "invalid method: %v", meth)
}
methodWrapper(0, typ, meth, target)
// For non-interface types, we also want *T wrappers.
if !typ.IsInterface() {
methodWrapper(1, typ, meth, target)
// For not-in-heap types, *T is a scalar, not pointer shaped,
// so the interface wrappers use **T.
if typ.NotInHeap() {
methodWrapper(2, typ, meth, target)
}
}
}
}
func methodWrapper(derefs int, tbase *types.Type, method *types.Field, target *ir.Package) {
wrapper := tbase
for i := 0; i < derefs; i++ {
wrapper = types.NewPtr(wrapper)
}
sym := ir.MethodSym(wrapper, method.Sym)
base.Assertf(!sym.Siggen(), "already generated wrapper %v", sym)
sym.SetSiggen(true)
wrappee := method.Type.Recv().Type
if types.Identical(wrapper, wrappee) ||
!types.IsMethodApplicable(wrapper, method) ||
!reflectdata.NeedEmit(tbase) {
return
}
// TODO(mdempsky): Use method.Pos instead?
pos := base.AutogeneratedPos
fn := newWrapperFunc(pos, sym, wrapper, method)
var recv ir.Node = fn.Nname.Type().Recv().Nname.(*ir.Name)
// For simple *T wrappers around T methods, panicwrap produces a
// nicer panic message.
if wrapper.IsPtr() && types.Identical(wrapper.Elem(), wrappee) {
cond := ir.NewBinaryExpr(pos, ir.OEQ, recv, types.BuiltinPkg.Lookup("nil").Def.(ir.Node))
then := []ir.Node{ir.NewCallExpr(pos, ir.OCALL, typecheck.LookupRuntime("panicwrap"), nil)}
fn.Body.Append(ir.NewIfStmt(pos, cond, then, nil))
}
// typecheck will add one implicit deref, if necessary,
// but not-in-heap types require more for their **T wrappers.
for i := 1; i < derefs; i++ {
recv = Implicit(ir.NewStarExpr(pos, recv))
}
addTailCall(pos, fn, recv, method)
finishWrapperFunc(fn, target)
}
func wrapMethodValue(recvType *types.Type, method *types.Field, target *ir.Package, needed bool) {
sym := ir.MethodSymSuffix(recvType, method.Sym, "-fm")
if sym.Uniq() {
return
}
sym.SetUniq(true)
// TODO(mdempsky): Use method.Pos instead?
pos := base.AutogeneratedPos
fn := newWrapperFunc(pos, sym, nil, method)
sym.Def = fn.Nname
// Declare and initialize variable holding receiver.
recv := ir.NewHiddenParam(pos, fn, typecheck.Lookup(".this"), recvType)
if !needed {
typecheck.Func(fn)
return
}
addTailCall(pos, fn, recv, method)
finishWrapperFunc(fn, target)
}
func newWrapperFunc(pos src.XPos, sym *types.Sym, wrapper *types.Type, method *types.Field) *ir.Func {
fn := ir.NewFunc(pos)
fn.SetDupok(true) // TODO(mdempsky): Leave unset for local, non-generic wrappers?
name := ir.NewNameAt(pos, sym)
ir.MarkFunc(name)
name.Func = fn
name.Defn = fn
fn.Nname = name
sig := newWrapperType(wrapper, method)
setType(name, sig)
// TODO(mdempsky): De-duplicate with similar logic in funcargs.
defParams := func(class ir.Class, params *types.Type) {
for _, param := range params.FieldSlice() {
name := ir.NewNameAt(param.Pos, param.Sym)
name.Class = class
setType(name, param.Type)
name.Curfn = fn
fn.Dcl = append(fn.Dcl, name)
param.Nname = name
}
}
defParams(ir.PPARAM, sig.Recvs())
defParams(ir.PPARAM, sig.Params())
defParams(ir.PPARAMOUT, sig.Results())
return fn
}
func finishWrapperFunc(fn *ir.Func, target *ir.Package) {
typecheck.Func(fn)
ir.WithFunc(fn, func() {
typecheck.Stmts(fn.Body)
})
// We generate wrappers after the global inlining pass,
// so we're responsible for applying inlining ourselves here.
// TODO(prattmic): plumb PGO.
inline.InlineCalls(fn, nil)
// The body of wrapper function after inlining may reveal new ir.OMETHVALUE node,
// we don't know whether wrapper function has been generated for it or not, so
// generate one immediately here.
//
// Further, after CL 492017, function that construct closures is allowed to be inlined,
// even though the closure itself can't be inline. So we also need to visit body of any
// closure that we see when visiting body of the wrapper function.
ir.VisitFuncAndClosures(fn, func(n ir.Node) {
if n, ok := n.(*ir.SelectorExpr); ok && n.Op() == ir.OMETHVALUE {
wrapMethodValue(n.X.Type(), n.Selection, target, true)
}
})
target.Decls = append(target.Decls, fn)
}
// newWrapperType returns a copy of the given signature type, but with
// the receiver parameter type substituted with recvType.
// If recvType is nil, newWrapperType returns a signature
// without a receiver parameter.
func newWrapperType(recvType *types.Type, method *types.Field) *types.Type {
clone := func(params []*types.Field) []*types.Field {
res := make([]*types.Field, len(params))
for i, param := range params {
sym := param.Sym
if sym == nil || sym.Name == "_" {
sym = typecheck.LookupNum(".anon", i)
}
res[i] = types.NewField(param.Pos, sym, param.Type)
res[i].SetIsDDD(param.IsDDD())
}
return res
}
sig := method.Type
var recv *types.Field
if recvType != nil {
recv = types.NewField(sig.Recv().Pos, typecheck.Lookup(".this"), recvType)
}
params := clone(sig.Params().FieldSlice())
results := clone(sig.Results().FieldSlice())
return types.NewSignature(recv, params, results)
}
func addTailCall(pos src.XPos, fn *ir.Func, recv ir.Node, method *types.Field) {
sig := fn.Nname.Type()
args := make([]ir.Node, sig.NumParams())
for i, param := range sig.Params().FieldSlice() {
args[i] = param.Nname.(*ir.Name)
}
// TODO(mdempsky): Support creating OTAILCALL, when possible. See reflectdata.methodWrapper.
// Not urgent though, because tail calls are currently incompatible with regabi anyway.
fn.SetWrapper(true) // TODO(mdempsky): Leave unset for tail calls?
dot := ir.NewSelectorExpr(pos, ir.OXDOT, recv, method.Sym)
call := typecheck.Call(pos, dot, args, method.Type.IsVariadic()).(*ir.CallExpr)
if method.Type.NumResults() == 0 {
fn.Body.Append(call)
return
}
ret := ir.NewReturnStmt(pos, nil)
ret.Results = []ir.Node{call}
fn.Body.Append(ret)
}
func setBasePos(pos src.XPos) {
// Set the position for any error messages we might print (e.g. too large types).
base.Pos = pos
}
// dictParamName is the name of the synthetic dictionary parameter
// added to shaped functions.
//
// N.B., this variable name is known to Delve:
// https://github.com/go-delve/delve/blob/cb91509630529e6055be845688fd21eb89ae8714/pkg/proc/eval.go#L28
const dictParamName = typecheck.LocalDictName
// shapeSig returns a copy of fn's signature, except adding a
// dictionary parameter and promoting the receiver parameter (if any)
// to a normal parameter.
//
// The parameter types.Fields are all copied too, so their Nname
// fields can be initialized for use by the shape function.
func shapeSig(fn *ir.Func, dict *readerDict) *types.Type {
sig := fn.Nname.Type()
oldRecv := sig.Recv()
var recv *types.Field
if oldRecv != nil {
recv = types.NewField(oldRecv.Pos, oldRecv.Sym, oldRecv.Type)
}
params := make([]*types.Field, 1+sig.Params().Fields().Len())
params[0] = types.NewField(fn.Pos(), fn.Sym().Pkg.Lookup(dictParamName), types.NewPtr(dict.varType()))
for i, param := range sig.Params().Fields().Slice() {
d := types.NewField(param.Pos, param.Sym, param.Type)
d.SetIsDDD(param.IsDDD())
params[1+i] = d
}
results := make([]*types.Field, sig.Results().Fields().Len())
for i, result := range sig.Results().Fields().Slice() {
results[i] = types.NewField(result.Pos, result.Sym, result.Type)
}
return types.NewSignature(recv, params, results)
}