go stencil 源码
golang stencil 代码
文件路径：/src/cmd/compile/internal/noder/stencil.go
// 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.
// This file will evolve, since we plan to do a mix of stenciling and passing
// around dictionaries.
package noder
import (
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/objw"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/obj"
"cmd/internal/src"
"fmt"
"go/constant"
)
// Enable extra consistency checks.
const doubleCheck = false
func assert(p bool) {
base.Assert(p)
}
// For outputting debug information on dictionary format and instantiated dictionaries
// (type arg, derived types, sub-dictionary, and itab entries).
var infoPrintMode = false
func infoPrint(format string, a ...interface{}) {
if infoPrintMode {
fmt.Printf(format, a...)
}
}
var geninst genInst
func BuildInstantiations() {
geninst.instInfoMap = make(map[*types.Sym]*instInfo)
geninst.buildInstantiations()
geninst.instInfoMap = nil
}
// buildInstantiations scans functions for generic function calls and methods, and
// creates the required instantiations. It also creates instantiated methods for all
// fully-instantiated generic types that have been encountered already or new ones
// that are encountered during the instantiation process. It scans all declarations
// in typecheck.Target.Decls first, before scanning any new instantiations created.
func (g *genInst) buildInstantiations() {
// Instantiate the methods of instantiated generic types that we have seen so far.
g.instantiateMethods()
// Scan all currentdecls for call to generic functions/methods.
n := len(typecheck.Target.Decls)
for i := 0; i < n; i++ {
g.scanForGenCalls(typecheck.Target.Decls[i])
}
// Scan all new instantiations created due to g.instantiateMethods() and the
// scan of current decls. This loop purposely runs until no new
// instantiations are created.
for i := 0; i < len(g.newInsts); i++ {
g.scanForGenCalls(g.newInsts[i])
}
g.finalizeSyms()
// All the instantiations and dictionaries have been created. Now go through
// each new instantiation and transform the various operations that need to make
// use of their dictionary.
l := len(g.newInsts)
for _, fun := range g.newInsts {
info := g.instInfoMap[fun.Sym()]
g.dictPass(info)
if doubleCheck {
ir.Visit(info.fun, func(n ir.Node) {
if n.Op() != ir.OCONVIFACE {
return
}
c := n.(*ir.ConvExpr)
if c.X.Type().HasShape() && !c.X.Type().IsInterface() {
ir.Dump("BAD FUNCTION", info.fun)
ir.Dump("BAD CONVERSION", c)
base.Fatalf("converting shape type to interface")
}
})
}
if base.Flag.W > 1 {
ir.Dump(fmt.Sprintf("\ndictpass %v", info.fun), info.fun)
}
}
assert(l == len(g.newInsts))
g.newInsts = nil
}
// scanForGenCalls scans a single function (or global assignment), looking for
// references to generic functions/methods. At each such reference, it creates any
// required instantiation and transforms the reference.
func (g *genInst) scanForGenCalls(decl ir.Node) {
switch decl.Op() {
case ir.ODCLFUNC:
if decl.Type().HasTParam() {
// Skip any generic functions
return
}
// transformCall() below depends on CurFunc being set.
ir.CurFunc = decl.(*ir.Func)
case ir.OAS, ir.OAS2, ir.OAS2DOTTYPE, ir.OAS2FUNC, ir.OAS2MAPR, ir.OAS2RECV, ir.OASOP:
// These are all the various kinds of global assignments,
// whose right-hand-sides might contain a function
// instantiation.
default:
// The other possible ops at the top level are ODCLCONST
// and ODCLTYPE, which don't have any function
// instantiations.
return
}
// Search for any function references using generic function/methods. Then
// create the needed instantiated function if it hasn't been created yet, and
// change to calling that function directly.
modified := false
closureRequired := false
// declInfo will be non-nil exactly if we are scanning an instantiated function
declInfo := g.instInfoMap[decl.Sym()]
ir.Visit(decl, func(n ir.Node) {
if n.Op() == ir.OFUNCINST {
// generic F, not immediately called
closureRequired = true
}
if (n.Op() == ir.OMETHEXPR || n.Op() == ir.OMETHVALUE) && len(deref(n.(*ir.SelectorExpr).X.Type()).RParams()) > 0 && !types.IsInterfaceMethod(n.(*ir.SelectorExpr).Selection.Type) {
// T.M or x.M, where T or x is generic, but not immediately
// called. Not necessary if the method selected is
// actually for an embedded interface field.
closureRequired = true
}
if n.Op() == ir.OCALL && n.(*ir.CallExpr).X.Op() == ir.OFUNCINST {
// We have found a function call using a generic function
// instantiation.
call := n.(*ir.CallExpr)
inst := call.X.(*ir.InstExpr)
nameNode, isMeth := g.getInstNameNode(inst)
targs := typecheck.TypesOf(inst.Targs)
st := g.getInstantiation(nameNode, targs, isMeth).fun
dictValue, usingSubdict := g.getDictOrSubdict(declInfo, n, nameNode, targs, isMeth)
if infoPrintMode {
dictkind := "Main dictionary"
if usingSubdict {
dictkind = "Sub-dictionary"
}
if inst.X.Op() == ir.OMETHVALUE {
fmt.Printf("%s in %v at generic method call: %v - %v\n", dictkind, decl, inst.X, call)
} else {
fmt.Printf("%s in %v at generic function call: %v - %v\n", dictkind, decl, inst.X, call)
}
}
// Transform the Call now, which changes OCALL to
// OCALLFUNC and does typecheckaste/assignconvfn. Do
// it before installing the instantiation, so we are
// checking against non-shape param types in
// typecheckaste.
transformCall(call)
// Replace the OFUNCINST with a direct reference to the
// new stenciled function
call.X = st.Nname
if inst.X.Op() == ir.OMETHVALUE {
// When we create an instantiation of a method
// call, we make it a function. So, move the
// receiver to be the first arg of the function
// call.
call.Args.Prepend(inst.X.(*ir.SelectorExpr).X)
}
// Add dictionary to argument list.
call.Args.Prepend(dictValue)
modified = true
}
if n.Op() == ir.OCALLMETH && n.(*ir.CallExpr).X.Op() == ir.ODOTMETH && len(deref(n.(*ir.CallExpr).X.Type().Recv().Type).RParams()) > 0 {
// Method call on a generic type, which was instantiated by stenciling.
// Method calls on explicitly instantiated types will have an OFUNCINST
// and are handled above.
call := n.(*ir.CallExpr)
meth := call.X.(*ir.SelectorExpr)
targs := deref(meth.Type().Recv().Type).RParams()
t := meth.X.Type()
baseType := deref(t).OrigType()
var gf *ir.Name
for _, m := range baseType.Methods().Slice() {
if meth.Sel == m.Sym {
gf = m.Nname.(*ir.Name)
break
}
}
// Transform the Call now, which changes OCALL
// to OCALLFUNC and does typecheckaste/assignconvfn.
transformCall(call)
st := g.getInstantiation(gf, targs, true).fun
dictValue, usingSubdict := g.getDictOrSubdict(declInfo, n, gf, targs, true)
if hasShapeTypes(targs) {
// We have to be using a subdictionary, since this is
// a generic method call.
assert(usingSubdict)
} else {
// We should use main dictionary, because the receiver is
// an instantiation already, see issue #53406.
assert(!usingSubdict)
}
// Transform to a function call, by appending the
// dictionary and the receiver to the args.
call.SetOp(ir.OCALLFUNC)
call.X = st.Nname
call.Args.Prepend(dictValue, meth.X)
modified = true
}
})
// If we found a reference to a generic instantiation that wasn't an
// immediate call, then traverse the nodes of decl again (with
// EditChildren rather than Visit), where we actually change the
// reference to the instantiation to a closure that captures the
// dictionary, then does a direct call.
// EditChildren is more expensive than Visit, so we only do this
// in the infrequent case of an OFUNCINST without a corresponding
// call.
if closureRequired {
modified = true
var edit func(ir.Node) ir.Node
var outer *ir.Func
if f, ok := decl.(*ir.Func); ok {
outer = f
}
edit = func(x ir.Node) ir.Node {
if x.Op() == ir.OFUNCINST {
child := x.(*ir.InstExpr).X
if child.Op() == ir.OMETHEXPR || child.Op() == ir.OMETHVALUE {
// Call EditChildren on child (x.X),
// not x, so that we don't do
// buildClosure() on the
// METHEXPR/METHVALUE nodes as well.
ir.EditChildren(child, edit)
return g.buildClosure(outer, x)
}
}
ir.EditChildren(x, edit)
switch {
case x.Op() == ir.OFUNCINST:
return g.buildClosure(outer, x)
case (x.Op() == ir.OMETHEXPR || x.Op() == ir.OMETHVALUE) &&
len(deref(x.(*ir.SelectorExpr).X.Type()).RParams()) > 0 &&
!types.IsInterfaceMethod(x.(*ir.SelectorExpr).Selection.Type):
return g.buildClosure(outer, x)
}
return x
}
edit(decl)
}
if base.Flag.W > 1 && modified {
ir.Dump(fmt.Sprintf("\nmodified %v", decl), decl)
}
ir.CurFunc = nil
// We may have seen new fully-instantiated generic types while
// instantiating any needed functions/methods in the above
// function. If so, instantiate all the methods of those types
// (which will then lead to more function/methods to scan in the loop).
g.instantiateMethods()
}
// buildClosure makes a closure to implement x, a OFUNCINST or OMETHEXPR/OMETHVALUE
// of generic type. outer is the containing function (or nil if closure is
// in a global assignment instead of a function).
func (g *genInst) buildClosure(outer *ir.Func, x ir.Node) ir.Node {
pos := x.Pos()
var target *ir.Func // target instantiated function/method
var dictValue ir.Node // dictionary to use
var rcvrValue ir.Node // receiver, if a method value
typ := x.Type() // type of the closure
var outerInfo *instInfo
if outer != nil {
outerInfo = g.instInfoMap[outer.Sym()]
}
usingSubdict := false
valueMethod := false
if x.Op() == ir.OFUNCINST {
inst := x.(*ir.InstExpr)
// Type arguments we're instantiating with.
targs := typecheck.TypesOf(inst.Targs)
// Find the generic function/method.
var gf *ir.Name
if inst.X.Op() == ir.ONAME {
// Instantiating a generic function call.
gf = inst.X.(*ir.Name)
} else if inst.X.Op() == ir.OMETHVALUE {
// Instantiating a method value x.M.
se := inst.X.(*ir.SelectorExpr)
rcvrValue = se.X
gf = se.Selection.Nname.(*ir.Name)
} else {
panic("unhandled")
}
// target is the instantiated function we're trying to call.
// For functions, the target expects a dictionary as its first argument.
// For method values, the target expects a dictionary and the receiver
// as its first two arguments.
// dictValue is the value to use for the dictionary argument.
target = g.getInstantiation(gf, targs, rcvrValue != nil).fun
dictValue, usingSubdict = g.getDictOrSubdict(outerInfo, x, gf, targs, rcvrValue != nil)
if infoPrintMode {
dictkind := "Main dictionary"
if usingSubdict {
dictkind = "Sub-dictionary"
}
if rcvrValue == nil {
fmt.Printf("%s in %v for generic function value %v\n", dictkind, outer, inst.X)
} else {
fmt.Printf("%s in %v for generic method value %v\n", dictkind, outer, inst.X)
}
}
} else { // ir.OMETHEXPR or ir.METHVALUE
// Method expression T.M where T is a generic type.
se := x.(*ir.SelectorExpr)
targs := deref(se.X.Type()).RParams()
if len(targs) == 0 {
panic("bad")
}
if x.Op() == ir.OMETHVALUE {
rcvrValue = se.X
}
// se.X.Type() is the top-level type of the method expression. To
// correctly handle method expressions involving embedded fields,
// look up the generic method below using the type of the receiver
// of se.Selection, since that will be the type that actually has
// the method.
recv := deref(se.Selection.Type.Recv().Type)
if len(recv.RParams()) == 0 {
// The embedded type that actually has the method is not
// actually generic, so no need to build a closure.
return x
}
baseType := recv.OrigType()
var gf *ir.Name
for _, m := range baseType.Methods().Slice() {
if se.Sel == m.Sym {
gf = m.Nname.(*ir.Name)
break
}
}
if !gf.Type().Recv().Type.IsPtr() {
// Remember if value method, so we can detect (*T).M case.
valueMethod = true
}
target = g.getInstantiation(gf, targs, true).fun
dictValue, usingSubdict = g.getDictOrSubdict(outerInfo, x, gf, targs, true)
if infoPrintMode {
dictkind := "Main dictionary"
if usingSubdict {
dictkind = "Sub-dictionary"
}
fmt.Printf("%s in %v for method expression %v\n", dictkind, outer, x)
}
}
// Build a closure to implement a function instantiation.
//
// func f[T any] (int, int) (int, int) { ...whatever... }
//
// Then any reference to f[int] not directly called gets rewritten to
//
// .dictN := ... dictionary to use ...
// func(a0, a1 int) (r0, r1 int) {
// return .inst.f[int](.dictN, a0, a1)
// }
//
// Similarly for method expressions,
//
// type g[T any] ....
// func (rcvr g[T]) f(a0, a1 int) (r0, r1 int) { ... }
//
// Any reference to g[int].f not directly called gets rewritten to
//
// .dictN := ... dictionary to use ...
// func(rcvr g[int], a0, a1 int) (r0, r1 int) {
// return .inst.g[int].f(.dictN, rcvr, a0, a1)
// }
//
// Also method values
//
// var x g[int]
//
// Any reference to x.f not directly called gets rewritten to
//
// .dictN := ... dictionary to use ...
// x2 := x
// func(a0, a1 int) (r0, r1 int) {
// return .inst.g[int].f(.dictN, x2, a0, a1)
// }
// Make a new internal function.
fn, formalParams, formalResults := startClosure(pos, outer, typ)
fn.SetWrapper(true) // See issue 52237
// This is the dictionary we want to use.
// It may be a constant, it may be the outer functions's dictionary, or it may be
// a subdictionary acquired from the outer function's dictionary.
// For the latter, dictVar is a variable in the outer function's scope, set to the subdictionary
// read from the outer function's dictionary.
var dictVar *ir.Name
var dictAssign *ir.AssignStmt
if outer != nil {
dictVar = ir.NewNameAt(pos, closureSym(outer, typecheck.LocalDictName, g.dnum))
g.dnum++
dictVar.Class = ir.PAUTO
typed(types.Types[types.TUINTPTR], dictVar)
dictVar.Curfn = outer
dictAssign = ir.NewAssignStmt(pos, dictVar, dictValue)
dictAssign.SetTypecheck(1)
dictVar.Defn = dictAssign
outer.Dcl = append(outer.Dcl, dictVar)
}
// assign the receiver to a temporary.
var rcvrVar *ir.Name
var rcvrAssign ir.Node
if rcvrValue != nil {
rcvrVar = ir.NewNameAt(pos, closureSym(outer, ".rcvr", g.dnum))
g.dnum++
typed(rcvrValue.Type(), rcvrVar)
rcvrAssign = ir.NewAssignStmt(pos, rcvrVar, rcvrValue)
rcvrAssign.SetTypecheck(1)
rcvrVar.Defn = rcvrAssign
if outer == nil {
rcvrVar.Class = ir.PEXTERN
typecheck.Target.Decls = append(typecheck.Target.Decls, rcvrAssign)
typecheck.Target.Externs = append(typecheck.Target.Externs, rcvrVar)
} else {
rcvrVar.Class = ir.PAUTO
rcvrVar.Curfn = outer
outer.Dcl = append(outer.Dcl, rcvrVar)
}
}
// Build body of closure. This involves just calling the wrapped function directly
// with the additional dictionary argument.
// First, figure out the dictionary argument.
var dict2Var ir.Node
if usingSubdict {
// Capture sub-dictionary calculated in the outer function
dict2Var = ir.CaptureName(pos, fn, dictVar)
typed(types.Types[types.TUINTPTR], dict2Var)
} else {
// Static dictionary, so can be used directly in the closure
dict2Var = dictValue
}
// Also capture the receiver variable.
var rcvr2Var *ir.Name
if rcvrValue != nil {
rcvr2Var = ir.CaptureName(pos, fn, rcvrVar)
}
// Build arguments to call inside the closure.
var args []ir.Node
// First the dictionary argument.
args = append(args, dict2Var)
// Then the receiver.
if rcvrValue != nil {
args = append(args, rcvr2Var)
}
// Then all the other arguments (including receiver for method expressions).
for i := 0; i < typ.NumParams(); i++ {
if x.Op() == ir.OMETHEXPR && i == 0 {
// If we are doing a method expression, we need to
// explicitly traverse any embedded fields in the receiver
// argument in order to call the method instantiation.
arg0 := formalParams[0].Nname.(ir.Node)
arg0 = typecheck.AddImplicitDots(ir.NewSelectorExpr(x.Pos(), ir.OXDOT, arg0, x.(*ir.SelectorExpr).Sel)).X
if valueMethod && arg0.Type().IsPtr() {
// For handling the (*T).M case: if we have a pointer
// receiver after following all the embedded fields,
// but it's a value method, add a star operator.
arg0 = ir.NewStarExpr(arg0.Pos(), arg0)
}
args = append(args, arg0)
} else {
args = append(args, formalParams[i].Nname.(*ir.Name))
}
}
// Build call itself.
var innerCall ir.Node = ir.NewCallExpr(pos, ir.OCALL, target.Nname, args)
innerCall.(*ir.CallExpr).IsDDD = typ.IsVariadic()
if len(formalResults) > 0 {
innerCall = ir.NewReturnStmt(pos, []ir.Node{innerCall})
}
// Finish building body of closure.
ir.CurFunc = fn
// TODO: set types directly here instead of using typecheck.Stmt
typecheck.Stmt(innerCall)
ir.CurFunc = nil
fn.Body = []ir.Node{innerCall}
// We're all done with the captured dictionary (and receiver, for method values).
ir.FinishCaptureNames(pos, outer, fn)
// Make a closure referencing our new internal function.
c := ir.UseClosure(fn.OClosure, typecheck.Target)
var init []ir.Node
if outer != nil {
init = append(init, dictAssign)
}
if rcvrValue != nil {
init = append(init, rcvrAssign)
}
return ir.InitExpr(init, c)
}
// instantiateMethods instantiates all the methods (and associated dictionaries) of
// all fully-instantiated generic types that have been added to typecheck.instTypeList.
// It continues until no more types are added to typecheck.instTypeList.
func (g *genInst) instantiateMethods() {
for {
instTypeList := typecheck.GetInstTypeList()
if len(instTypeList) == 0 {
break
}
typecheck.ClearInstTypeList()
for _, typ := range instTypeList {
assert(!typ.HasShape())
// Mark runtime type as needed, since this ensures that the
// compiler puts out the needed DWARF symbols, when this
// instantiated type has a different package from the local
// package.
typecheck.NeedRuntimeType(typ)
// Lookup the method on the base generic type, since methods may
// not be set on imported instantiated types.
baseType := typ.OrigType()
for j, _ := range typ.Methods().Slice() {
if baseType.Methods().Slice()[j].Nointerface() {
typ.Methods().Slice()[j].SetNointerface(true)
}
baseNname := baseType.Methods().Slice()[j].Nname.(*ir.Name)
// Eagerly generate the instantiations and dictionaries that implement these methods.
// We don't use the instantiations here, just generate them (and any
// further instantiations those generate, etc.).
// Note that we don't set the Func for any methods on instantiated
// types. Their signatures don't match so that would be confusing.
// Direct method calls go directly to the instantiations, implemented above.
// Indirect method calls use wrappers generated in reflectcall. Those wrappers
// will use these instantiations if they are needed (for interface tables or reflection).
_ = g.getInstantiation(baseNname, typ.RParams(), true)
_ = g.getDictionarySym(baseNname, typ.RParams(), true)
}
}
}
}
// getInstNameNode returns the name node for the method or function being instantiated, and a bool which is true if a method is being instantiated.
func (g *genInst) getInstNameNode(inst *ir.InstExpr) (*ir.Name, bool) {
if meth, ok := inst.X.(*ir.SelectorExpr); ok {
return meth.Selection.Nname.(*ir.Name), true
} else {
return inst.X.(*ir.Name), false
}
}
// getDictOrSubdict returns, for a method/function call or reference (node n) in an
// instantiation (described by instInfo), a node which is accessing a sub-dictionary
// or main/static dictionary, as needed, and also returns a boolean indicating if a
// sub-dictionary was accessed. nameNode is the particular function or method being
// called/referenced, and targs are the type arguments.
func (g *genInst) getDictOrSubdict(declInfo *instInfo, n ir.Node, nameNode *ir.Name, targs []*types.Type, isMeth bool) (ir.Node, bool) {
var dict ir.Node
usingSubdict := false
if declInfo != nil {
entry := -1
for i, de := range declInfo.dictInfo.subDictCalls {
if n == de.callNode {
entry = declInfo.dictInfo.startSubDict + i
break
}
}
// If the entry is not found, it may be that this node did not have
// any type args that depend on type params, so we need a main
// dictionary, not a sub-dictionary.
if entry >= 0 {
dict = getDictionaryEntry(n.Pos(), declInfo.dictParam, entry, declInfo.dictInfo.dictLen)
usingSubdict = true
}
}
if !usingSubdict {
dict = g.getDictionaryValue(n.Pos(), nameNode, targs, isMeth)
}
return dict, usingSubdict
}
// checkFetchBody checks if a generic body can be fetched, but hasn't been loaded
// yet. If so, it imports the body.
func checkFetchBody(nameNode *ir.Name) {
if nameNode.Func.Body == nil && nameNode.Func.Inl != nil {
// If there is no body yet but Func.Inl exists, then we can
// import the whole generic body.
assert(nameNode.Func.Inl.Cost == 1 && nameNode.Sym().Pkg != types.LocalPkg)
typecheck.ImportBody(nameNode.Func)
assert(nameNode.Func.Inl.Body != nil)
nameNode.Func.Body = nameNode.Func.Inl.Body
nameNode.Func.Dcl = nameNode.Func.Inl.Dcl
}
}
// getInstantiation gets the instantiation and dictionary of the function or method nameNode
// with the type arguments shapes. If the instantiated function is not already
// cached, then it calls genericSubst to create the new instantiation.
func (g *genInst) getInstantiation(nameNode *ir.Name, shapes []*types.Type, isMeth bool) *instInfo {
if nameNode.Func == nil {
// If nameNode.Func is nil, this must be a reference to a method of
// an imported instantiated type. We will have already called
// g.instantiateMethods() on the fully-instantiated type, so
// g.instInfoMap[sym] will be non-nil below.
rcvr := nameNode.Type().Recv()
if rcvr == nil || !deref(rcvr.Type).IsFullyInstantiated() {
base.FatalfAt(nameNode.Pos(), "Unexpected function instantiation %v with no body", nameNode)
}
} else {
checkFetchBody(nameNode)
}
var tparams []*types.Type
if isMeth {
// Get the type params from the method receiver (after skipping
// over any pointer)
recvType := nameNode.Type().Recv().Type
recvType = deref(recvType)
if recvType.IsFullyInstantiated() {
// Get the type of the base generic type, so we get
// its original typeparams.
recvType = recvType.OrigType()
}
tparams = recvType.RParams()
} else {
fields := nameNode.Type().TParams().Fields().Slice()
tparams = make([]*types.Type, len(fields))
for i, f := range fields {
tparams[i] = f.Type
}
}
// Convert any non-shape type arguments to their shape, so we can reduce the
// number of instantiations we have to generate. You can actually have a mix
// of shape and non-shape arguments, because of inferred or explicitly
// specified concrete type args.
s1 := make([]*types.Type, len(shapes))
for i, t := range shapes {
var tparam *types.Type
// Shapes are grouped differently for structural types, so we
// pass the type param to Shapify(), so we can distinguish.
tparam = tparams[i]
if !t.IsShape() {
s1[i] = typecheck.Shapify(t, i, tparam)
} else {
// Already a shape, but make sure it has the correct index.
s1[i] = typecheck.Shapify(shapes[i].Underlying(), i, tparam)
}
}
shapes = s1
sym := typecheck.MakeFuncInstSym(nameNode.Sym(), shapes, false, isMeth)
info := g.instInfoMap[sym]
if info == nil {
// If instantiation doesn't exist yet, create it and add
// to the list of decls.
info = &instInfo{
dictInfo: &dictInfo{},
}
info.dictInfo.shapeToBound = make(map[*types.Type]*types.Type)
if sym.Def != nil {
// This instantiation must have been imported from another
// package (because it was needed for inlining), so we should
// not re-generate it and have conflicting definitions for the
// symbol (issue #50121). It will have already gone through the
// dictionary transformations of dictPass, so we don't actually
// need the info.dictParam and info.shapeToBound info filled in
// below. We just set the imported instantiation as info.fun.
assert(sym.Pkg != types.LocalPkg)
info.fun = sym.Def.(*ir.Name).Func
assert(info.fun != nil)
g.instInfoMap[sym] = info
return info
}
// genericSubst fills in info.dictParam and info.shapeToBound.
st := g.genericSubst(sym, nameNode, tparams, shapes, isMeth, info)
info.fun = st
g.instInfoMap[sym] = info
// getInstInfo fills in info.dictInfo.
g.getInstInfo(st, shapes, info)
if base.Flag.W > 1 {
ir.Dump(fmt.Sprintf("\nstenciled %v", st), st)
}
// This ensures that the linker drops duplicates of this instantiation.
// All just works!
st.SetDupok(true)
typecheck.Target.Decls = append(typecheck.Target.Decls, st)
g.newInsts = append(g.newInsts, st)
}
return info
}
// Struct containing info needed for doing the substitution as we create the
// instantiation of a generic function with specified type arguments.
type subster struct {
g *genInst
isMethod bool // If a method is being instantiated
newf *ir.Func // Func node for the new stenciled function
ts typecheck.Tsubster
info *instInfo // Place to put extra info in the instantiation
skipClosure bool // Skip substituting closures
// Map from non-nil, non-ONAME node n to slice of all m, where m.Defn = n
defnMap map[ir.Node][]**ir.Name
}
// genericSubst returns a new function with name newsym. The function is an
// instantiation of a generic function or method specified by namedNode with type
// args shapes. For a method with a generic receiver, it returns an instantiated
// function type where the receiver becomes the first parameter. For either a generic
// method or function, a dictionary parameter is the added as the very first
// parameter. genericSubst fills in info.dictParam and info.shapeToBound.
func (g *genInst) genericSubst(newsym *types.Sym, nameNode *ir.Name, tparams []*types.Type, shapes []*types.Type, isMethod bool, info *instInfo) *ir.Func {
gf := nameNode.Func
// Pos of the instantiated function is same as the generic function
newf := ir.NewFunc(gf.Pos())
newf.Pragma = gf.Pragma // copy over pragmas from generic function to stenciled implementation.
newf.Endlineno = gf.Endlineno
newf.Nname = ir.NewNameAt(gf.Pos(), newsym)
newf.Nname.Func = newf
newf.Nname.Defn = newf
newsym.Def = newf.Nname
savef := ir.CurFunc
// transformCall/transformReturn (called during stenciling of the body)
// depend on ir.CurFunc being set.
ir.CurFunc = newf
assert(len(tparams) == len(shapes))
subst := &subster{
g: g,
isMethod: isMethod,
newf: newf,
info: info,
ts: typecheck.Tsubster{
Tparams: tparams,
Targs: shapes,
Vars: make(map[*ir.Name]*ir.Name),
},
defnMap: make(map[ir.Node][]**ir.Name),
}
newf.Dcl = make([]*ir.Name, 0, len(gf.Dcl)+1)
// Create the needed dictionary param
dictionarySym := newsym.Pkg.Lookup(typecheck.LocalDictName)
dictionaryType := types.Types[types.TUINTPTR]
dictionaryName := ir.NewNameAt(gf.Pos(), dictionarySym)
typed(dictionaryType, dictionaryName)
dictionaryName.Class = ir.PPARAM
dictionaryName.Curfn = newf
newf.Dcl = append(newf.Dcl, dictionaryName)
for _, n := range gf.Dcl {
if n.Sym().Name == typecheck.LocalDictName {
panic("already has dictionary")
}
newf.Dcl = append(newf.Dcl, subst.localvar(n))
}
dictionaryArg := types.NewField(gf.Pos(), dictionarySym, dictionaryType)
dictionaryArg.Nname = dictionaryName
info.dictParam = dictionaryName
// We add the dictionary as the first parameter in the function signature.
// We also transform a method type to the corresponding function type
// (make the receiver be the next parameter after the dictionary).
oldt := nameNode.Type()
var args []*types.Field
args = append(args, dictionaryArg)
args = append(args, oldt.Recvs().FieldSlice()...)
args = append(args, oldt.Params().FieldSlice()...)
// Replace the types in the function signature via subst.fields.
// Ugly: also, we have to insert the Name nodes of the parameters/results into
// the function type. The current function type has no Nname fields set,
// because it came via conversion from the types2 type.
newt := types.NewSignature(oldt.Pkg(), nil, nil,
subst.fields(ir.PPARAM, args, newf.Dcl),
subst.fields(ir.PPARAMOUT, oldt.Results().FieldSlice(), newf.Dcl))
typed(newt, newf.Nname)
ir.MarkFunc(newf.Nname)
newf.SetTypecheck(1)
// Make sure name/type of newf is set before substituting the body.
newf.Body = subst.list(gf.Body)
if len(newf.Body) == 0 {
// Ensure the body is nonempty, for issue 49524.
// TODO: have some other way to detect the difference between
// a function declared with no body, vs. one with an empty body?
newf.Body = append(newf.Body, ir.NewBlockStmt(gf.Pos(), nil))
}
if len(subst.defnMap) > 0 {
base.Fatalf("defnMap is not empty")
}
for i, tp := range tparams {
info.dictInfo.shapeToBound[shapes[i]] = subst.ts.Typ(tp.Bound())
}
ir.CurFunc = savef
return subst.newf
}
// localvar creates a new name node for the specified local variable and enters it
// in subst.vars. It substitutes type arguments for type parameters in the type of
// name as needed.
func (subst *subster) localvar(name *ir.Name) *ir.Name {
m := ir.NewNameAt(name.Pos(), name.Sym())
if name.IsClosureVar() {
m.SetIsClosureVar(true)
}
m.SetType(subst.ts.Typ(name.Type()))
m.BuiltinOp = name.BuiltinOp
m.Curfn = subst.newf
m.Class = name.Class
assert(name.Class != ir.PEXTERN && name.Class != ir.PFUNC)
m.Func = name.Func
subst.ts.Vars[name] = m
m.SetTypecheck(1)
m.DictIndex = name.DictIndex
if name.Defn != nil {
if name.Defn.Op() == ir.ONAME {
// This is a closure variable, so its Defn is the outer
// captured variable, which has already been substituted.
m.Defn = subst.node(name.Defn)
} else {
// The other values of Defn are nodes in the body of the
// function, so just remember the mapping so we can set Defn
// properly in node() when we create the new body node. We
// always call localvar() on all the local variables before
// we substitute the body.
slice := subst.defnMap[name.Defn]
subst.defnMap[name.Defn] = append(slice, &m)
}
}
if name.Outer != nil {
m.Outer = subst.node(name.Outer).(*ir.Name)
}
return m
}
// getDictionaryEntry gets the i'th entry in the dictionary dict.
func getDictionaryEntry(pos src.XPos, dict *ir.Name, i int, size int) ir.Node {
// Convert dictionary to *[N]uintptr
// All entries in the dictionary are pointers. They all point to static data, though, so we
// treat them as uintptrs so the GC doesn't need to keep track of them.
d := ir.NewConvExpr(pos, ir.OCONVNOP, types.Types[types.TUNSAFEPTR], dict)
d.SetTypecheck(1)
d = ir.NewConvExpr(pos, ir.OCONVNOP, types.NewArray(types.Types[types.TUINTPTR], int64(size)).PtrTo(), d)
d.SetTypecheck(1)
types.CheckSize(d.Type().Elem())
// Load entry i out of the dictionary.
deref := ir.NewStarExpr(pos, d)
typed(d.Type().Elem(), deref)
idx := ir.NewConstExpr(constant.MakeUint64(uint64(i)), dict) // TODO: what to set orig to?
typed(types.Types[types.TUINTPTR], idx)
r := ir.NewIndexExpr(pos, deref, idx)
typed(types.Types[types.TUINTPTR], r)
return r
}
// getDictionaryEntryAddr gets the address of the i'th entry in dictionary dict.
func getDictionaryEntryAddr(pos src.XPos, dict *ir.Name, i int, size int) ir.Node {
a := ir.NewAddrExpr(pos, getDictionaryEntry(pos, dict, i, size))
typed(types.Types[types.TUINTPTR].PtrTo(), a)
return a
}
// getDictionaryType returns a *runtime._type from the dictionary entry i (which
// refers to a type param or a derived type that uses type params). It uses the
// specified dictionary dictParam, rather than the one in info.dictParam.
func getDictionaryType(info *instInfo, dictParam *ir.Name, pos src.XPos, i int) ir.Node {
if i < 0 || i >= info.dictInfo.startSubDict {
base.Fatalf(fmt.Sprintf("bad dict index %d", i))
}
r := getDictionaryEntry(pos, dictParam, i, info.dictInfo.startSubDict)
// change type of retrieved dictionary entry to *byte, which is the
// standard typing of a *runtime._type in the compiler
typed(types.Types[types.TUINT8].PtrTo(), r)
return r
}
// node is like DeepCopy(), but substitutes ONAME nodes based on subst.ts.vars, and
// also descends into closures. It substitutes type arguments for type parameters in
// all the new nodes and does the transformations that were delayed on the generic
// function.
func (subst *subster) node(n ir.Node) ir.Node {
// Use closure to capture all state needed by the ir.EditChildren argument.
var edit func(ir.Node) ir.Node
edit = func(x ir.Node) ir.Node {
// Analogous to ir.SetPos() at beginning of typecheck.typecheck() -
// allows using base.Pos during the transform functions, just like
// the tc*() functions.
ir.SetPos(x)
switch x.Op() {
case ir.OTYPE:
return ir.TypeNode(subst.ts.Typ(x.Type()))
case ir.ONAME:
if v := subst.ts.Vars[x.(*ir.Name)]; v != nil {
return v
}
if ir.IsBlank(x) {
// Special case, because a blank local variable is
// not in the fn.Dcl list.
m := ir.NewNameAt(x.Pos(), ir.BlankNode.Sym())
return typed(subst.ts.Typ(x.Type()), m)
}
return x
case ir.ONONAME:
// This handles the identifier in a type switch guard
fallthrough
case ir.OLITERAL, ir.ONIL:
if x.Sym() != nil {
return x
}
}
m := ir.Copy(x)
slice, ok := subst.defnMap[x]
if ok {
// We just copied a non-ONAME node which was the Defn value
// of a local variable. Set the Defn value of the copied
// local variable to this new Defn node.
for _, ptr := range slice {
(*ptr).Defn = m
}
delete(subst.defnMap, x)
}
if _, isExpr := m.(ir.Expr); isExpr {
t := x.Type()
if t == nil {
// Check for known cases where t can be nil (call
// that has no return values, and key expressions)
// and otherwise cause a fatal error.
_, isCallExpr := m.(*ir.CallExpr)
_, isStructKeyExpr := m.(*ir.StructKeyExpr)
_, isKeyExpr := m.(*ir.KeyExpr)
if !isCallExpr && !isStructKeyExpr && !isKeyExpr && x.Op() != ir.OPANIC &&
x.Op() != ir.OCLOSE {
base.FatalfAt(m.Pos(), "Nil type for %v", x)
}
} else if x.Op() != ir.OCLOSURE {
m.SetType(subst.ts.Typ(x.Type()))
}
}
old := subst.skipClosure
// For unsafe.{Alignof,Offsetof,Sizeof}, subster will transform them to OLITERAL nodes,
// and discard their arguments. However, their children nodes were already process before,
// thus if they contain any closure, the closure was still be added to package declarations
// queue for processing later. Thus, genInst will fail to generate instantiation for the
// closure because of lacking dictionary information, see issue #53390.
if call, ok := m.(*ir.CallExpr); ok && call.X.Op() == ir.ONAME {
switch call.X.Name().BuiltinOp {
case ir.OALIGNOF, ir.OOFFSETOF, ir.OSIZEOF:
subst.skipClosure = true
}
}
ir.EditChildren(m, edit)
subst.skipClosure = old
m.SetTypecheck(1)
// Do the transformations that we delayed on the generic function
// node, now that we have substituted in the type args.
switch x.Op() {
case ir.OEQ, ir.ONE, ir.OLT, ir.OLE, ir.OGT, ir.OGE:
transformCompare(m.(*ir.BinaryExpr))
case ir.OSLICE, ir.OSLICE3:
transformSlice(m.(*ir.SliceExpr))
case ir.OADD:
m = transformAdd(m.(*ir.BinaryExpr))
case ir.OINDEX:
transformIndex(m.(*ir.IndexExpr))
case ir.OAS2:
as2 := m.(*ir.AssignListStmt)
transformAssign(as2, as2.Lhs, as2.Rhs)
case ir.OAS:
as := m.(*ir.AssignStmt)
if as.Y != nil {
// transformAssign doesn't handle the case
// of zeroing assignment of a dcl (rhs[0] is nil).
lhs, rhs := []ir.Node{as.X}, []ir.Node{as.Y}
transformAssign(as, lhs, rhs)
as.X, as.Y = lhs[0], rhs[0]
}
case ir.OASOP:
as := m.(*ir.AssignOpStmt)
transformCheckAssign(as, as.X)
case ir.ORETURN:
transformReturn(m.(*ir.ReturnStmt))
case ir.OSEND:
transformSend(m.(*ir.SendStmt))
case ir.OSELECT:
transformSelect(m.(*ir.SelectStmt))
case ir.OCOMPLIT:
transformCompLit(m.(*ir.CompLitExpr))
case ir.OADDR:
transformAddr(m.(*ir.AddrExpr))
case ir.OLITERAL:
t := m.Type()
if t != x.Type() {
// types2 will give us a constant with a type T,
// if an untyped constant is used with another
// operand of type T (in a provably correct way).
// When we substitute in the type args during
// stenciling, we now know the real type of the
// constant. We may then need to change the
// BasicLit.val to be the correct type (e.g.
// convert an int64Val constant to a floatVal
// constant).
m.SetType(types.UntypedInt) // use any untyped type for DefaultLit to work
m = typecheck.DefaultLit(m, t)
}
case ir.OXDOT:
// Finish the transformation of an OXDOT, unless this is
// bound call or field access on a type param. A bound call
// or field access on a type param will be transformed during
// the dictPass. Otherwise, m will be transformed to an
// OMETHVALUE node. It will be transformed to an ODOTMETH or
// ODOTINTER node if we find in the OCALL case below that the
// method value is actually called.
mse := m.(*ir.SelectorExpr)
if src := mse.X.Type(); !src.IsShape() {
transformDot(mse, false)
}
case ir.OCALL:
call := m.(*ir.CallExpr)
switch call.X.Op() {
case ir.OTYPE:
// Transform the conversion, now that we know the
// type argument.
m = transformConvCall(call)
case ir.OMETHVALUE, ir.OMETHEXPR:
// Redo the transformation of OXDOT, now that we
// know the method value is being called. Then
// transform the call.
call.X.(*ir.SelectorExpr).SetOp(ir.OXDOT)
transformDot(call.X.(*ir.SelectorExpr), true)
transformCall(call)
case ir.ODOT, ir.ODOTPTR:
// An OXDOT for a generic receiver was resolved to
// an access to a field which has a function
// value. Transform the call to that function, now
// that the OXDOT was resolved.
transformCall(call)
case ir.ONAME:
name := call.X.Name()
if name.BuiltinOp != ir.OXXX {
m = transformBuiltin(call)
} else {
// This is the case of a function value that was a
// type parameter (implied to be a function via a
// structural constraint) which is now resolved.
transformCall(call)
}
case ir.OFUNCINST:
// A call with an OFUNCINST will get transformed
// in stencil() once we have created & attached the
// instantiation to be called.
// We must transform the arguments of the call now, though,
// so that any needed CONVIFACE nodes are exposed,
// so the dictionary format is correct.
transformEarlyCall(call)
case ir.OXDOT:
// This is the case of a bound call or a field access
// on a typeparam, which will be handled in the
// dictPass. As with OFUNCINST, we must transform the
// arguments of the call now, so any needed CONVIFACE
// nodes are exposed.
transformEarlyCall(call)
case ir.ODOTTYPE, ir.ODOTTYPE2:
// These are DOTTYPEs that could get transformed into
// ODYNAMIC DOTTYPEs by the dict pass.
default:
// Transform a call for all other values of
// call.X.Op() that don't require any special
// handling.
transformCall(call)
}
case ir.OCLOSURE:
if subst.skipClosure {
break
}
// We're going to create a new closure from scratch, so clear m
// to avoid using the ir.Copy by accident until we reassign it.
m = nil
x := x.(*ir.ClosureExpr)
// Need to duplicate x.Func.Nname, x.Func.Dcl, x.Func.ClosureVars, and
// x.Func.Body.
oldfn := x.Func
newfn := ir.NewClosureFunc(oldfn.Pos(), subst.newf != nil)
ir.NameClosure(newfn.OClosure, subst.newf)
saveNewf := subst.newf
ir.CurFunc = newfn
subst.newf = newfn
newfn.Dcl = subst.namelist(oldfn.Dcl)
// Make a closure variable for the dictionary of the
// containing function.
cdict := ir.CaptureName(oldfn.Pos(), newfn, subst.info.dictParam)
typed(types.Types[types.TUINTPTR], cdict)
ir.FinishCaptureNames(oldfn.Pos(), saveNewf, newfn)
newfn.ClosureVars = append(newfn.ClosureVars, subst.namelist(oldfn.ClosureVars)...)
// Copy that closure variable to a local one.
// Note: this allows the dictionary to be captured by child closures.
// See issue 47723.
ldict := ir.NewNameAt(x.Pos(), newfn.Sym().Pkg.Lookup(typecheck.LocalDictName))
typed(types.Types[types.TUINTPTR], ldict)
ldict.Class = ir.PAUTO
ldict.Curfn = newfn
newfn.Dcl = append(newfn.Dcl, ldict)
as := ir.NewAssignStmt(x.Pos(), ldict, cdict)
as.SetTypecheck(1)
ldict.Defn = as
newfn.Body.Append(as)
// Create inst info for the instantiated closure. The dict
// param is the closure variable for the dictionary of the
// outer function. Since the dictionary is shared, use the
// same dictInfo.
cinfo := &instInfo{
fun: newfn,
dictParam: ldict,
dictInfo: subst.info.dictInfo,
}
subst.g.instInfoMap[newfn.Nname.Sym()] = cinfo
typed(subst.ts.Typ(oldfn.Nname.Type()), newfn.Nname)
typed(newfn.Nname.Type(), newfn.OClosure)
newfn.SetTypecheck(1)
outerinfo := subst.info
subst.info = cinfo
// Make sure type of closure function is set before doing body.
newfn.Body.Append(subst.list(oldfn.Body)...)
subst.info = outerinfo
subst.newf = saveNewf
ir.CurFunc = saveNewf
m = ir.UseClosure(newfn.OClosure, typecheck.Target)
subst.g.newInsts = append(subst.g.newInsts, m.(*ir.ClosureExpr).Func)
m.(*ir.ClosureExpr).SetInit(subst.list(x.Init()))
case ir.OSWITCH:
m := m.(*ir.SwitchStmt)
if m.Tag != nil && m.Tag.Op() == ir.OTYPESW {
break // Nothing to do here for type switches.
}
if m.Tag != nil && !types.IsComparable(m.Tag.Type()) {
break // Nothing to do here for un-comparable types.
}
if m.Tag != nil && !m.Tag.Type().IsEmptyInterface() && m.Tag.Type().HasShape() {
// To implement a switch on a value that is or has a type parameter, we first convert
// that thing we're switching on to an interface{}.
m.Tag = assignconvfn(m.Tag, types.Types[types.TINTER])
}
for _, c := range m.Cases {
for i, x := range c.List {
// If we have a case that is or has a type parameter, convert that case
// to an interface{}.
if !x.Type().IsEmptyInterface() && x.Type().HasShape() {
c.List[i] = assignconvfn(x, types.Types[types.TINTER])
}
}
}
}
return m
}
return edit(n)
}
// dictPass takes a function instantiation and does the transformations on the
// operations that need to make use of the dictionary param.
func (g *genInst) dictPass(info *instInfo) {
savef := ir.CurFunc
ir.CurFunc = info.fun
callMap := make(map[ir.Node]bool)
var edit func(ir.Node) ir.Node
edit = func(m ir.Node) ir.Node {
if m.Op() == ir.OCALL && m.(*ir.CallExpr).X.Op() == ir.OXDOT {
callMap[m.(*ir.CallExpr).X] = true
}
ir.EditChildren(m, edit)
switch m.Op() {
case ir.OCLOSURE:
newf := m.(*ir.ClosureExpr).Func
ir.CurFunc = newf
outerinfo := info
info = g.instInfoMap[newf.Nname.Sym()]
body := newf.Body
for i, n := range body {
body[i] = edit(n)
}
info = outerinfo
ir.CurFunc = info.fun
case ir.OXDOT:
// This is the case of a dot access on a type param. This is
// typically a bound call on the type param, but could be a
// field access, if the constraint has a single structural type.
mse := m.(*ir.SelectorExpr)
src := mse.X.Type()
assert(src.IsShape())
if mse.X.Op() == ir.OTYPE {
// Method expression T.M
idx := findMethodExprClosure(info.dictInfo, mse)
c := getDictionaryEntryAddr(m.Pos(), info.dictParam, info.dictInfo.startMethodExprClosures+idx, info.dictInfo.dictLen)
m = ir.NewConvExpr(m.Pos(), ir.OCONVNOP, mse.Type(), c)
m.SetTypecheck(1)
} else {
// If we can't find the selected method in the
// AllMethods of the bound, then this must be an access
// to a field of a structural type. If so, we skip the
// dictionary lookups - transformDot() will convert to
// the desired direct field access.
if isBoundMethod(info.dictInfo, mse) {
if callMap[m] {
// The OCALL surrounding this XDOT will rewrite the call
// to use the method expression closure directly.
break
}
// Convert this method value to a closure.
// TODO: use method expression closure.
dst := info.dictInfo.shapeToBound[mse.X.Type()]
// Implement x.M as a conversion-to-bound-interface
// 1) convert x to the bound interface
// 2) select method value M on that interface
if src.IsInterface() {
// If type arg is an interface (unusual case),
// we do a type assert to the type bound.
mse.X = assertToBound(info, info.dictParam, m.Pos(), mse.X, dst)
} else {
mse.X = convertUsingDictionary(info, info.dictParam, m.Pos(), mse.X, m, dst)
}
}
transformDot(mse, false)
}
case ir.OCALL:
call := m.(*ir.CallExpr)
op := call.X.Op()
if op == ir.OXDOT {
// This is a call of a method value where the value has a type parameter type.
// We transform to a call of the appropriate method expression closure
// in the dictionary.
// So if x has a type parameter type:
// _ = x.m(a)
// Rewrite to:
// _ = methexpr<m>(x, a)
se := call.X.(*ir.SelectorExpr)
call.SetOp(ir.OCALLFUNC)
idx := findMethodExprClosure(info.dictInfo, se)
c := getDictionaryEntryAddr(se.Pos(), info.dictParam, info.dictInfo.startMethodExprClosures+idx, info.dictInfo.dictLen)
t := typecheck.NewMethodType(se.Type(), se.X.Type())
call.X = ir.NewConvExpr(se.Pos(), ir.OCONVNOP, t, c)
typed(t, call.X)
call.Args.Prepend(se.X)
break
// TODO: deref case?
}
if op == ir.OMETHVALUE {
// Redo the transformation of OXDOT, now that we
// know the method value is being called.
call.X.(*ir.SelectorExpr).SetOp(ir.OXDOT)
transformDot(call.X.(*ir.SelectorExpr), true)
}
transformCall(call)
case ir.OCONVIFACE:
if m.Type().IsEmptyInterface() && m.(*ir.ConvExpr).X.Type().IsEmptyInterface() {
// Was T->interface{}, after stenciling it is now interface{}->interface{}.
// No longer need the conversion. See issue 48276.
m.(*ir.ConvExpr).SetOp(ir.OCONVNOP)
break
}
mce := m.(*ir.ConvExpr)
// Note: x's argument is still typed as a type parameter.
// m's argument now has an instantiated type.
if mce.X.Type().HasShape() || (m.Type().HasShape() && !m.Type().IsEmptyInterface()) {
m = convertUsingDictionary(info, info.dictParam, m.Pos(), mce.X, m, m.Type())
}
case ir.ODOTTYPE, ir.ODOTTYPE2:
dt := m.(*ir.TypeAssertExpr)
if !dt.Type().HasShape() && !(dt.X.Type().HasShape() && !dt.X.Type().IsEmptyInterface()) {
break
}
var rtype, itab ir.Node
if dt.Type().IsInterface() || dt.X.Type().IsEmptyInterface() {
// TODO(mdempsky): Investigate executing this block unconditionally.
ix := findDictType(info, m.Type())
assert(ix >= 0)
rtype = getDictionaryType(info, info.dictParam, dt.Pos(), ix)
} else {
// nonempty interface to noninterface. Need an itab.
ix := -1
for i, ic := range info.dictInfo.itabConvs {
if ic == m {
ix = info.dictInfo.startItabConv + i
break
}
}
assert(ix >= 0)
itab = getDictionaryEntry(dt.Pos(), info.dictParam, ix, info.dictInfo.dictLen)
}
op := ir.ODYNAMICDOTTYPE
if m.Op() == ir.ODOTTYPE2 {
op = ir.ODYNAMICDOTTYPE2
}
m = ir.NewDynamicTypeAssertExpr(dt.Pos(), op, dt.X, rtype)
m.(*ir.DynamicTypeAssertExpr).ITab = itab
m.SetType(dt.Type())
m.SetTypecheck(1)
case ir.OCASE:
if _, ok := m.(*ir.CommClause); ok {
// This is not a type switch. TODO: Should we use an OSWITCH case here instead of OCASE?
break
}
m := m.(*ir.CaseClause)
for i, c := range m.List {
if c.Op() == ir.OTYPE && c.Type().HasShape() {
// Use a *runtime._type for the dynamic type.
ix := findDictType(info, m.List[i].Type())
assert(ix >= 0)
dt := ir.NewDynamicType(c.Pos(), getDictionaryEntry(c.Pos(), info.dictParam, ix, info.dictInfo.dictLen))
// For type switch from nonempty interfaces to non-interfaces, we need an itab as well.
if !m.List[i].Type().IsInterface() {
if _, ok := info.dictInfo.type2switchType[m.List[i]]; ok {
// Type switch from nonempty interface. We need a *runtime.itab
// for the dynamic type.
ix := -1
for j, ic := range info.dictInfo.itabConvs {
if ic == m.List[i] {
ix = info.dictInfo.startItabConv + j
break
}
}
assert(ix >= 0)
dt.ITab = getDictionaryEntry(c.Pos(), info.dictParam, ix, info.dictInfo.dictLen)
}
}
typed(m.List[i].Type(), dt)
m.List[i] = dt
}
}
}
return m
}
edit(info.fun)
ir.CurFunc = savef
}
// findDictType looks for type t in the typeparams or derived types in the generic
// function info.gfInfo. This will indicate the dictionary entry with the
// correct concrete type for the associated instantiated function.
func findDictType(info *instInfo, t *types.Type) int {
for i, dt := range info.dictInfo.shapeParams {
if dt == t {
return i
}
}
for i, dt := range info.dictInfo.derivedTypes {
if types.IdenticalStrict(dt, t) {
return i + len(info.dictInfo.shapeParams)
}
}
return -1
}
// convertUsingDictionary converts instantiated value v (type v.Type()) to an interface
// type dst, by returning a new set of nodes that make use of a dictionary entry. in is the
// instantiated node of the CONVIFACE node or XDOT node (for a bound method call) that is causing the
// conversion.
func convertUsingDictionary(info *instInfo, dictParam *ir.Name, pos src.XPos, v ir.Node, in ir.Node, dst *types.Type) ir.Node {
assert(v.Type().HasShape() || (in.Type().HasShape() && !in.Type().IsEmptyInterface()))
assert(dst.IsInterface())
if v.Type().IsInterface() {
// Converting from an interface. The shape-ness of the source doesn't really matter, as
// we'll be using the concrete type from the first interface word.
if dst.IsEmptyInterface() {
// Converting I2E. OCONVIFACE does that for us, and doesn't depend
// on what the empty interface was instantiated with. No dictionary entry needed.
v = ir.NewConvExpr(pos, ir.OCONVIFACE, dst, v)
v.SetTypecheck(1)
return v
}
if !in.Type().HasShape() {
// Regular OCONVIFACE works if the destination isn't parameterized.
v = ir.NewConvExpr(pos, ir.OCONVIFACE, dst, v)
v.SetTypecheck(1)
return v
}
// We get the destination interface type from the dictionary and the concrete
// type from the argument's itab. Call runtime.convI2I to get the new itab.
tmp := typecheck.Temp(v.Type())
as := ir.NewAssignStmt(pos, tmp, v)
as.SetTypecheck(1)
itab := ir.NewUnaryExpr(pos, ir.OITAB, tmp)
typed(types.Types[types.TUINTPTR].PtrTo(), itab)
idata := ir.NewUnaryExpr(pos, ir.OIDATA, tmp)
typed(types.Types[types.TUNSAFEPTR], idata)
fn := typecheck.LookupRuntime("convI2I")
fn.SetTypecheck(1)
types.CalcSize(fn.Type())
call := ir.NewCallExpr(pos, ir.OCALLFUNC, fn, nil)
typed(types.Types[types.TUINT8].PtrTo(), call)
ix := findDictType(info, in.Type())
assert(ix >= 0)
inter := getDictionaryType(info, dictParam, pos, ix)
call.Args = []ir.Node{inter, itab}
i := ir.NewBinaryExpr(pos, ir.OEFACE, call, idata)
typed(dst, i)
i.PtrInit().Append(as)
return i
}
var rt ir.Node
if !dst.IsEmptyInterface() {
// We should have an itab entry in the dictionary. Using this itab
// will be more efficient than converting to an empty interface first
// and then type asserting to dst.
ix := -1
for i, ic := range info.dictInfo.itabConvs {
if ic == in {
ix = info.dictInfo.startItabConv + i
break
}
}
assert(ix >= 0)
rt = getDictionaryEntry(pos, dictParam, ix, info.dictInfo.dictLen)
} else {
ix := findDictType(info, v.Type())
assert(ix >= 0)
// Load the actual runtime._type of the type parameter from the dictionary.
rt = getDictionaryType(info, dictParam, pos, ix)
}
// Figure out what the data field of the interface will be.
data := ir.NewConvExpr(pos, ir.OCONVIDATA, nil, v)
typed(types.Types[types.TUNSAFEPTR], data)
// Build an interface from the type and data parts.
var i ir.Node = ir.NewBinaryExpr(pos, ir.OEFACE, rt, data)
typed(dst, i)
return i
}
func (subst *subster) namelist(l []*ir.Name) []*ir.Name {
s := make([]*ir.Name, len(l))
for i, n := range l {
s[i] = subst.localvar(n)
}
return s
}
func (subst *subster) list(l []ir.Node) []ir.Node {
s := make([]ir.Node, len(l))
for i, n := range l {
s[i] = subst.node(n)
}
return s
}
// fields sets the Nname field for the Field nodes inside a type signature, based
// on the corresponding in/out parameters in dcl. It depends on the in and out
// parameters being in order in dcl.
func (subst *subster) fields(class ir.Class, oldfields []*types.Field, dcl []*ir.Name) []*types.Field {
// Find the starting index in dcl of declarations of the class (either
// PPARAM or PPARAMOUT).
var i int
for i = range dcl {
if dcl[i].Class == class {
break
}
}
// Create newfields nodes that are copies of the oldfields nodes, but
// with substitution for any type params, and with Nname set to be the node in
// Dcl for the corresponding PPARAM or PPARAMOUT.
newfields := make([]*types.Field, len(oldfields))
for j := range oldfields {
newfields[j] = oldfields[j].Copy()
newfields[j].Type = subst.ts.Typ(oldfields[j].Type)
// A PPARAM field will be missing from dcl if its name is
// unspecified or specified as "_". So, we compare the dcl sym
// with the field sym (or sym of the field's Nname node). (Unnamed
// results still have a name like ~r2 in their Nname node.) If
// they don't match, this dcl (if there is one left) must apply to
// a later field.
if i < len(dcl) && (dcl[i].Sym() == oldfields[j].Sym ||
(oldfields[j].Nname != nil && dcl[i].Sym() == oldfields[j].Nname.Sym())) {
newfields[j].Nname = dcl[i]
i++
}
}
return newfields
}
// deref does a single deref of type t, if it is a pointer type.
func deref(t *types.Type) *types.Type {
if t.IsPtr() {
return t.Elem()
}
return t
}
// markTypeUsed marks type t as used in order to help avoid dead-code elimination of
// needed methods.
func markTypeUsed(t *types.Type, lsym *obj.LSym) {
if t.IsInterface() {
return
}
// TODO: This is somewhat overkill, we really only need it
// for types that are put into interfaces.
// Note: this relocation is also used in cmd/link/internal/ld/dwarf.go
reflectdata.MarkTypeUsedInInterface(t, lsym)
}
// getDictionarySym returns the dictionary for the named generic function gf, which
// is instantiated with the type arguments targs.
func (g *genInst) getDictionarySym(gf *ir.Name, targs []*types.Type, isMeth bool) *types.Sym {
if len(targs) == 0 {
base.Fatalf("%s should have type arguments", gf.Sym().Name)
}
// Enforce that only concrete types can make it to here.
for _, t := range targs {
if t.HasShape() {
panic(fmt.Sprintf("shape %+v in dictionary for %s", t, gf.Sym().Name))
}
}
// Get a symbol representing the dictionary.
sym := typecheck.MakeDictSym(gf.Sym(), targs, isMeth)
// Initialize the dictionary, if we haven't yet already.
lsym := sym.Linksym()
if len(lsym.P) > 0 {
// We already started creating this dictionary and its lsym.
return sym
}
infoPrint("=== Creating dictionary %v\n", sym.Name)
off := 0
// Emit an entry for each targ (concrete type or gcshape).
for _, t := range targs {
infoPrint(" * %v\n", t)
s := reflectdata.TypeLinksym(t)
off = objw.SymPtr(lsym, off, s, 0)
markTypeUsed(t, lsym)
}
instInfo := g.getInstantiation(gf, targs, isMeth)
info := instInfo.dictInfo
subst := typecheck.Tsubster{
Tparams: info.shapeParams,
Targs: targs,
}
// Emit an entry for each derived type (after substituting targs)
for _, t := range info.derivedTypes {
ts := subst.Typ(t)
infoPrint(" - %v\n", ts)
s := reflectdata.TypeLinksym(ts)
off = objw.SymPtr(lsym, off, s, 0)
markTypeUsed(ts, lsym)
}
// Emit an entry for each subdictionary (after substituting targs)
for _, subDictInfo := range info.subDictCalls {
var sym *types.Sym
n := subDictInfo.callNode
switch n.Op() {
case ir.OCALL, ir.OCALLFUNC, ir.OCALLMETH:
call := n.(*ir.CallExpr)
if call.X.Op() == ir.OXDOT || call.X.Op() == ir.ODOTMETH {
var nameNode *ir.Name
se := call.X.(*ir.SelectorExpr)
if se.X.Type().IsShape() {
// This is a method call enabled by a type bound.
tparam := se.X.Type()
if call.X.Op() == ir.ODOTMETH {
// We need this extra check for method expressions,
// which don't add in the implicit XDOTs.
tmpse := ir.NewSelectorExpr(src.NoXPos, ir.OXDOT, se.X, se.Sel)
tmpse = typecheck.AddImplicitDots(tmpse)
tparam = tmpse.X.Type()
}
if !tparam.IsShape() {
// The method expression is not
// really on a typeparam.
break
}
ix := -1
for i, shape := range info.shapeParams {
if shape == tparam {
ix = i
break
}
}
assert(ix >= 0)
recvType := targs[ix]
if recvType.IsInterface() || len(recvType.RParams()) == 0 {
// No sub-dictionary entry is
// actually needed, since the
// type arg is not an
// instantiated type that
// will have generic methods.
break
}
// This is a method call for an
// instantiated type, so we need a
// sub-dictionary.
targs := recvType.RParams()
genRecvType := recvType.OrigType()
nameNode = typecheck.Lookdot1(call.X, se.Sel, genRecvType, genRecvType.Methods(), 1).Nname.(*ir.Name)
sym = g.getDictionarySym(nameNode, targs, true)
} else {
// This is the case of a normal
// method call on a generic type.
assert(subDictInfo.savedXNode == se)
sym = g.getSymForMethodCall(se, &subst)
}
} else {
inst, ok := call.X.(*ir.InstExpr)
if ok {
// Code hasn't been transformed yet
assert(subDictInfo.savedXNode == inst)
}
// If !ok, then the generic method/function call has
// already been transformed to a shape instantiation
// call. Either way, use the SelectorExpr/InstExpr
// node saved in info.
cex := subDictInfo.savedXNode
if se, ok := cex.(*ir.SelectorExpr); ok {
sym = g.getSymForMethodCall(se, &subst)
} else {
inst := cex.(*ir.InstExpr)
nameNode := inst.X.(*ir.Name)
subtargs := typecheck.TypesOf(inst.Targs)
for i, t := range subtargs {
subtargs[i] = subst.Typ(t)
}
sym = g.getDictionarySym(nameNode, subtargs, false)
}
}
case ir.OFUNCINST:
inst := n.(*ir.InstExpr)
nameNode := inst.X.(*ir.Name)
subtargs := typecheck.TypesOf(inst.Targs)
for i, t := range subtargs {
subtargs[i] = subst.Typ(t)
}
sym = g.getDictionarySym(nameNode, subtargs, false)
case ir.OXDOT, ir.OMETHEXPR, ir.OMETHVALUE:
sym = g.getSymForMethodCall(n.(*ir.SelectorExpr), &subst)
default:
assert(false)
}
if sym == nil {
// Unused sub-dictionary entry, just emit 0.
off = objw.Uintptr(lsym, off, 0)
infoPrint(" - Unused subdict entry\n")
} else {
off = objw.SymPtr(lsym, off, sym.Linksym(), 0)
infoPrint(" - Subdict %v\n", sym.Name)
}
}
g.instantiateMethods()
delay := &delayInfo{
gf: gf,
targs: targs,
sym: sym,
off: off,
isMeth: isMeth,
}
g.dictSymsToFinalize = append(g.dictSymsToFinalize, delay)
return sym
}
// getSymForMethodCall gets the dictionary sym for a method call, method value, or method
// expression that has selector se. subst gives the substitution from shape types to
// concrete types.
func (g *genInst) getSymForMethodCall(se *ir.SelectorExpr, subst *typecheck.Tsubster) *types.Sym {
// For everything except method expressions, 'recvType = deref(se.X.Type)' would
// also give the receiver type. For method expressions with embedded types, we
// need to look at the type of the selection to get the final receiver type.
recvType := deref(se.Selection.Type.Recv().Type)
genRecvType := recvType.OrigType()
nameNode := typecheck.Lookdot1(se, se.Sel, genRecvType, genRecvType.Methods(), 1).Nname.(*ir.Name)
subtargs := recvType.RParams()
s2targs := make([]*types.Type, len(subtargs))
for i, t := range subtargs {
s2targs[i] = subst.Typ(t)
}
return g.getDictionarySym(nameNode, s2targs, true)
}
// finalizeSyms finishes up all dictionaries on g.dictSymsToFinalize, by writing out
// any needed LSyms for itabs. The itab lsyms create wrappers which need various
// dictionaries and method instantiations to be complete, so, to avoid recursive
// dependencies, we finalize the itab lsyms only after all dictionaries syms and
// instantiations have been created.
// Also handles writing method expression closures into the dictionaries.
func (g *genInst) finalizeSyms() {
for _, d := range g.dictSymsToFinalize {
infoPrint("=== Finalizing dictionary %s\n", d.sym.Name)
lsym := d.sym.Linksym()
instInfo := g.getInstantiation(d.gf, d.targs, d.isMeth)
info := instInfo.dictInfo
subst := typecheck.Tsubster{
Tparams: info.shapeParams,
Targs: d.targs,
}
// Emit an entry for each itab
for _, n := range info.itabConvs {
var srctype, dsttype *types.Type
switch n.Op() {
case ir.OXDOT, ir.OMETHVALUE:
se := n.(*ir.SelectorExpr)
srctype = subst.Typ(se.X.Type())
dsttype = subst.Typ(info.shapeToBound[se.X.Type()])
case ir.ODOTTYPE, ir.ODOTTYPE2:
srctype = subst.Typ(n.(*ir.TypeAssertExpr).Type())
dsttype = subst.Typ(n.(*ir.TypeAssertExpr).X.Type())
case ir.OCONVIFACE:
srctype = subst.Typ(n.(*ir.ConvExpr).X.Type())
dsttype = subst.Typ(n.Type())
case ir.OTYPE:
srctype = subst.Typ(n.Type())
dsttype = subst.Typ(info.type2switchType[n])
default:
base.Fatalf("itab entry with unknown op %s", n.Op())
}
if srctype.IsInterface() || dsttype.IsEmptyInterface() {
// No itab is wanted if src type is an interface. We
// will use a type assert instead.
d.off = objw.Uintptr(lsym, d.off, 0)
infoPrint(" + Unused itab entry for %v\n", srctype)
} else {
// Make sure all new fully-instantiated types have
// their methods created before generating any itabs.
g.instantiateMethods()
itabLsym := reflectdata.ITabLsym(srctype, dsttype)
d.off = objw.SymPtr(lsym, d.off, itabLsym, 0)
markTypeUsed(srctype, lsym)
infoPrint(" + Itab for (%v,%v)\n", srctype, dsttype)
}
}
// Emit an entry for each method expression closure.
// Each entry is a (captureless) closure pointing to the method on the instantiating type.
// In other words, the entry is a runtime.funcval whose fn field is set to the method
// in question, and has no other fields. The address of this dictionary entry can be
// cast to a func of the appropriate type.
// TODO: do these need to be done when finalizing, or can we do them earlier?
for _, bf := range info.methodExprClosures {
rcvr := d.targs[bf.idx]
rcvr2 := deref(rcvr)
found := false
typecheck.CalcMethods(rcvr2) // Ensure methods on all instantiating types are computed.
for _, f := range rcvr2.AllMethods().Slice() {
if f.Sym.Name == bf.name {
codePtr := ir.MethodSym(rcvr, f.Sym).Linksym()
d.off = objw.SymPtr(lsym, d.off, codePtr, 0)
infoPrint(" + MethodExprClosure for %v.%s\n", rcvr, bf.name)
found = true
break
}
}
if !found {
base.Fatalf("method %s on %v not found", bf.name, rcvr)
}
}
objw.Global(lsym, int32(d.off), obj.DUPOK|obj.RODATA)
infoPrint("=== Finalized dictionary %s\n", d.sym.Name)
}
g.dictSymsToFinalize = nil
}
func (g *genInst) getDictionaryValue(pos src.XPos, gf *ir.Name, targs []*types.Type, isMeth bool) ir.Node {
sym := g.getDictionarySym(gf, targs, isMeth)
// Make (or reuse) a node referencing the dictionary symbol.
var n *ir.Name
if sym.Def != nil {
n = sym.Def.(*ir.Name)
} else {
// We set the position of a static dictionary to be the position of
// one of its uses.
n = ir.NewNameAt(pos, sym)
n.Curfn = ir.CurFunc
n.SetType(types.Types[types.TUINTPTR]) // should probably be [...]uintptr, but doesn't really matter
n.SetTypecheck(1)
n.Class = ir.PEXTERN
sym.Def = n
}
// Return the address of the dictionary. Addr node gets position that was passed in.
np := typecheck.NodAddrAt(pos, n)
// Note: treat dictionary pointers as uintptrs, so they aren't pointers
// with respect to GC. That saves on stack scanning work, write barriers, etc.
// We can get away with it because dictionaries are global variables.
// TODO: use a cast, or is typing directly ok?
np.SetType(types.Types[types.TUINTPTR])
np.SetTypecheck(1)
return np
}
// hasShapeNodes returns true if the type of any node in targs has a shape.
func hasShapeNodes(targs []ir.Ntype) bool {
for _, n := range targs {
if n.Type().HasShape() {
return true
}
}
return false
}
// hasShapeTypes returns true if any type in targs has a shape.
func hasShapeTypes(targs []*types.Type) bool {
for _, t := range targs {
if t.HasShape() {
return true
}
}
return false
}
// getInstInfo get the dictionary format for a function instantiation- type params, derived
// types, and needed subdictionaries, itabs, and method expression closures.
func (g *genInst) getInstInfo(st *ir.Func, shapes []*types.Type, instInfo *instInfo) {
info := instInfo.dictInfo
info.shapeParams = shapes
for _, t := range info.shapeParams {
b := info.shapeToBound[t]
if b.HasShape() {
// If a type bound is parameterized (unusual case), then we
// may need its derived type to do a type assert when doing a
// bound call for a type arg that is an interface.
addType(info, nil, b)
}
}
for _, n := range st.Dcl {
addType(info, n, n.Type())
n.DictIndex = uint16(findDictType(instInfo, n.Type()) + 1)
}
if infoPrintMode {
fmt.Printf(">>> InstInfo for %v\n", st)
for _, t := range info.shapeParams {
fmt.Printf(" Typeparam %v\n", t)
}
}
// Map to remember when we have seen an instantiated function value or method
// expression/value as part of a call, so we can determine when we encounter
// an uncalled function value or method expression/value.
callMap := make(map[ir.Node]bool)
var visitFunc func(ir.Node)
visitFunc = func(n ir.Node) {
switch n.Op() {
case ir.OFUNCINST:
if !callMap[n] && hasShapeNodes(n.(*ir.InstExpr).Targs) {
infoPrint(" Closure&subdictionary required at generic function value %v\n", n.(*ir.InstExpr).X)
info.subDictCalls = append(info.subDictCalls, subDictInfo{callNode: n, savedXNode: nil})
}
case ir.OMETHEXPR, ir.OMETHVALUE:
if !callMap[n] && !types.IsInterfaceMethod(n.(*ir.SelectorExpr).Selection.Type) &&
len(deref(n.(*ir.SelectorExpr).X.Type()).RParams()) > 0 &&
hasShapeTypes(deref(n.(*ir.SelectorExpr).X.Type()).RParams()) {
if n.(*ir.SelectorExpr).X.Op() == ir.OTYPE {
infoPrint(" Closure&subdictionary required at generic meth expr %v\n", n)
} else {
infoPrint(" Closure&subdictionary required at generic meth value %v\n", n)
}
info.subDictCalls = append(info.subDictCalls, subDictInfo{callNode: n, savedXNode: nil})
}
case ir.OCALL:
ce := n.(*ir.CallExpr)
if ce.X.Op() == ir.OFUNCINST {
callMap[ce.X] = true
if hasShapeNodes(ce.X.(*ir.InstExpr).Targs) {
infoPrint(" Subdictionary at generic function/method call: %v - %v\n", ce.X.(*ir.InstExpr).X, n)
// Save the instExpr node for the function call,
// since we will lose this information when the
// generic function call is transformed to a call
// on the shape instantiation.
info.subDictCalls = append(info.subDictCalls, subDictInfo{callNode: n, savedXNode: ce.X})
}
}
// Note: this XDOT code is not actually needed as long as we
// continue to disable type parameters on RHS of type
// declarations (#45639).
if ce.X.Op() == ir.OXDOT {
callMap[ce.X] = true
if isBoundMethod(info, ce.X.(*ir.SelectorExpr)) {
infoPrint(" Optional subdictionary at generic bound call: %v\n", n)
info.subDictCalls = append(info.subDictCalls, subDictInfo{callNode: n, savedXNode: nil})
}
}
case ir.OCALLMETH:
ce := n.(*ir.CallExpr)
if ce.X.Op() == ir.ODOTMETH &&
len(deref(ce.X.(*ir.SelectorExpr).X.Type()).RParams()) > 0 {
callMap[ce.X] = true
if hasShapeTypes(deref(ce.X.(*ir.SelectorExpr).X.Type()).RParams()) {
infoPrint(" Subdictionary at generic method call: %v\n", n)
// Save the selector for the method call, since we
// will eventually lose this information when the
// generic method call is transformed into a
// function call on the method shape instantiation.
info.subDictCalls = append(info.subDictCalls, subDictInfo{callNode: n, savedXNode: ce.X})
}
}
case ir.OCONVIFACE:
if n.Type().IsInterface() && !n.Type().IsEmptyInterface() &&
(n.Type().HasShape() || n.(*ir.ConvExpr).X.Type().HasShape()) {
infoPrint(" Itab for interface conv: %v\n", n)
info.itabConvs = append(info.itabConvs, n)
}
case ir.OXDOT:
se := n.(*ir.SelectorExpr)
if se.X.Op() == ir.OTYPE && se.X.Type().IsShape() {
// Method expression.
addMethodExprClosure(info, se)
break
}
if isBoundMethod(info, se) {
if callMap[n] {
// Method value called directly. Use method expression closure.
addMethodExprClosure(info, se)
break
}
// Method value not called directly. Still doing the old way.
infoPrint(" Itab for bound call: %v\n", n)
info.itabConvs = append(info.itabConvs, n)
}
case ir.ODOTTYPE, ir.ODOTTYPE2:
if !n.(*ir.TypeAssertExpr).Type().IsInterface() && !n.(*ir.TypeAssertExpr).X.Type().IsEmptyInterface() {
infoPrint(" Itab for dot type: %v\n", n)
info.itabConvs = append(info.itabConvs, n)
}
case ir.OCLOSURE:
// Visit the closure body and add all relevant entries to the
// dictionary of the outer function (closure will just use
// the dictionary of the outer function).
cfunc := n.(*ir.ClosureExpr).Func
for _, n1 := range cfunc.Body {
ir.Visit(n1, visitFunc)
}
for _, n := range cfunc.Dcl {
n.DictIndex = uint16(findDictType(instInfo, n.Type()) + 1)
}
case ir.OSWITCH:
ss := n.(*ir.SwitchStmt)
if ss.Tag != nil && ss.Tag.Op() == ir.OTYPESW &&
!ss.Tag.(*ir.TypeSwitchGuard).X.Type().IsEmptyInterface() {
for _, cc := range ss.Cases {
for _, c := range cc.List {
if c.Op() == ir.OTYPE && c.Type().HasShape() {
// Type switch from a non-empty interface - might need an itab.
infoPrint(" Itab for type switch: %v\n", c)
info.itabConvs = append(info.itabConvs, c)
if info.type2switchType == nil {
info.type2switchType = map[ir.Node]*types.Type{}
}
info.type2switchType[c] = ss.Tag.(*ir.TypeSwitchGuard).X.Type()
}
}
}
}
}
addType(info, n, n.Type())
}
for _, stmt := range st.Body {
ir.Visit(stmt, visitFunc)
}
if infoPrintMode {
for _, t := range info.derivedTypes {
fmt.Printf(" Derived type %v\n", t)
}
fmt.Printf(">>> Done Instinfo\n")
}
info.startSubDict = len(info.shapeParams) + len(info.derivedTypes)
info.startItabConv = len(info.shapeParams) + len(info.derivedTypes) + len(info.subDictCalls)
info.startMethodExprClosures = len(info.shapeParams) + len(info.derivedTypes) + len(info.subDictCalls) + len(info.itabConvs)
info.dictLen = len(info.shapeParams) + len(info.derivedTypes) + len(info.subDictCalls) + len(info.itabConvs) + len(info.methodExprClosures)
}
// isBoundMethod returns true if the selection indicated by se is a bound method of
// se.X. se.X must be a shape type (i.e. substituted directly from a type param). If
// isBoundMethod returns false, then the selection must be a field access of a
// structural type.
func isBoundMethod(info *dictInfo, se *ir.SelectorExpr) bool {
bound := info.shapeToBound[se.X.Type()]
return typecheck.Lookdot1(se, se.Sel, bound, bound.AllMethods(), 1) != nil
}
func shapeIndex(info *dictInfo, t *types.Type) int {
for i, s := range info.shapeParams {
if s == t {
return i
}
}
base.Fatalf("can't find type %v in shape params", t)
return -1
}
// addMethodExprClosure adds the T.M method expression to the list of bound method expressions
// used in the generic body.
// isBoundMethod must have returned true on the same arguments.
func addMethodExprClosure(info *dictInfo, se *ir.SelectorExpr) {
idx := shapeIndex(info, se.X.Type())
name := se.Sel.Name
for _, b := range info.methodExprClosures {
if idx == b.idx && name == b.name {
return
}
}
infoPrint(" Method expression closure for %v.%s\n", info.shapeParams[idx], name)
info.methodExprClosures = append(info.methodExprClosures, methodExprClosure{idx: idx, name: name})
}
// findMethodExprClosure finds the entry in the dictionary to use for the T.M
// method expression encoded in se.
// isBoundMethod must have returned true on the same arguments.
func findMethodExprClosure(info *dictInfo, se *ir.SelectorExpr) int {
idx := shapeIndex(info, se.X.Type())
name := se.Sel.Name
for i, b := range info.methodExprClosures {
if idx == b.idx && name == b.name {
return i
}
}
base.Fatalf("can't find method expression closure for %s %s", se.X.Type(), name)
return -1
}
// addType adds t to info.derivedTypes if it is parameterized type (which is not
// just a simple shape) that is different from any existing type on
// info.derivedTypes.
func addType(info *dictInfo, n ir.Node, t *types.Type) {
if t == nil || !t.HasShape() {
return
}
if t.IsShape() {
return
}
if t.Kind() == types.TFUNC && n != nil &&
(t.Recv() != nil || n.Op() == ir.ONAME && n.Name().Class == ir.PFUNC) {
// Don't use the type of a named generic function or method,
// since that is parameterized by other typeparams.
// (They all come from arguments of a FUNCINST node.)
return
}
if doubleCheck && !parameterizedBy(t, info.shapeParams) {
base.Fatalf("adding type with invalid parameters %+v", t)
}
if t.Kind() == types.TSTRUCT && t.IsFuncArgStruct() {
// Multiple return values are not a relevant new type (?).
return
}
// Ignore a derived type we've already added.
for _, et := range info.derivedTypes {
if types.IdenticalStrict(t, et) {
return
}
}
info.derivedTypes = append(info.derivedTypes, t)
}
// parameterizedBy returns true if t is parameterized by (at most) params.
func parameterizedBy(t *types.Type, params []*types.Type) bool {
return parameterizedBy1(t, params, map[*types.Type]bool{})
}
func parameterizedBy1(t *types.Type, params []*types.Type, visited map[*types.Type]bool) bool {
if visited[t] {
return true
}
visited[t] = true
if t.Sym() != nil && len(t.RParams()) > 0 {
// This defined type is instantiated. Check the instantiating types.
for _, r := range t.RParams() {
if !parameterizedBy1(r, params, visited) {
return false
}
}
return true
}
if t.IsShape() {
// Check if t is one of the allowed parameters in scope.
for _, p := range params {
if p == t {
return true
}
}
// Couldn't find t in the list of allowed parameters.
return false
}
switch t.Kind() {
case types.TARRAY, types.TPTR, types.TSLICE, types.TCHAN:
return parameterizedBy1(t.Elem(), params, visited)
case types.TMAP:
return parameterizedBy1(t.Key(), params, visited) && parameterizedBy1(t.Elem(), params, visited)
case types.TFUNC:
return parameterizedBy1(t.TParams(), params, visited) && parameterizedBy1(t.Recvs(), params, visited) && parameterizedBy1(t.Params(), params, visited) && parameterizedBy1(t.Results(), params, visited)
case types.TSTRUCT:
for _, f := range t.Fields().Slice() {
if !parameterizedBy1(f.Type, params, visited) {
return false
}
}
return true
case types.TINTER:
for _, f := range t.Methods().Slice() {
if !parameterizedBy1(f.Type, params, visited) {
return false
}
}
return true
case types.TINT, types.TINT8, types.TINT16, types.TINT32, types.TINT64,
types.TUINT, types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64,
types.TUINTPTR, types.TBOOL, types.TSTRING, types.TFLOAT32, types.TFLOAT64, types.TCOMPLEX64, types.TCOMPLEX128, types.TUNSAFEPTR:
return true
case types.TUNION:
for i := 0; i < t.NumTerms(); i++ {
tt, _ := t.Term(i)
if !parameterizedBy1(tt, params, visited) {
return false
}
}
return true
default:
base.Fatalf("bad type kind %+v", t)
return true
}
}
// startClosures starts creation of a closure that has the function type typ. It
// creates all the formal params and results according to the type typ. On return,
// the body and closure variables of the closure must still be filled in, and
// ir.UseClosure() called.
func startClosure(pos src.XPos, outer *ir.Func, typ *types.Type) (*ir.Func, []*types.Field, []*types.Field) {
// Make a new internal function.
fn := ir.NewClosureFunc(pos, outer != nil)
ir.NameClosure(fn.OClosure, outer)
// Build formal argument and return lists.
var formalParams []*types.Field // arguments of closure
var formalResults []*types.Field // returns of closure
for i := 0; i < typ.NumParams(); i++ {
t := typ.Params().Field(i).Type
arg := ir.NewNameAt(pos, closureSym(outer, "a", i))
arg.Class = ir.PPARAM
typed(t, arg)
arg.Curfn = fn
fn.Dcl = append(fn.Dcl, arg)
f := types.NewField(pos, arg.Sym(), t)
f.Nname = arg
f.SetIsDDD(typ.Params().Field(i).IsDDD())
formalParams = append(formalParams, f)
}
for i := 0; i < typ.NumResults(); i++ {
t := typ.Results().Field(i).Type
result := ir.NewNameAt(pos, closureSym(outer, "r", i)) // TODO: names not needed?
result.Class = ir.PPARAMOUT
typed(t, result)
result.Curfn = fn
fn.Dcl = append(fn.Dcl, result)
f := types.NewField(pos, result.Sym(), t)
f.Nname = result
formalResults = append(formalResults, f)
}
// Build an internal function with the right signature.
closureType := types.NewSignature(typ.Pkg(), nil, nil, formalParams, formalResults)
typed(closureType, fn.Nname)
typed(typ, fn.OClosure)
fn.SetTypecheck(1)
return fn, formalParams, formalResults
}
// closureSym returns outer.Sym().Pkg.LookupNum(prefix, n).
// If outer is nil, then types.LocalPkg is used instead.
func closureSym(outer *ir.Func, prefix string, n int) *types.Sym {
pkg := types.LocalPkg
if outer != nil {
pkg = outer.Sym().Pkg
}
return pkg.LookupNum(prefix, n)
}
// assertToBound returns a new node that converts a node rcvr with interface type to
// the 'dst' interface type.
func assertToBound(info *instInfo, dictVar *ir.Name, pos src.XPos, rcvr ir.Node, dst *types.Type) ir.Node {
if !dst.HasShape() {
return typed(dst, ir.NewTypeAssertExpr(pos, rcvr, nil))
}
ix := findDictType(info, dst)
assert(ix >= 0)
rt := getDictionaryType(info, dictVar, pos, ix)
return typed(dst, ir.NewDynamicTypeAssertExpr(pos, ir.ODYNAMICDOTTYPE, rcvr, rt))
}
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