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sym = pkg.Lookup(name)
return
}
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func (r *reader) hasTypeParams() bool {
return r.dict.hasTypeParams()
}
func (dict *readerDict) hasTypeParams() bool {
return dict != nil && len(dict.targs) != 0
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}
// @@@ 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.
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if name.Sym().Pkg == types.LocalPkg || r.hasTypeParams() {
name.Defn = fn
}
fn.Pragma = r.pragmaFlag()
r.linkname(name)
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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()
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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())
if name.Pragma()&ir.NotInHeap != 0 {
typ.SetNotInHeap(true)
}
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]
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} 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)
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// For each (typ, iface) pair, we write *runtime._type pointers
// for typ and iface, as well as the *runtime.itab pointer for the
// pair. This is wasteful, but it simplifies worrying about tricky
// cases like instantiating type parameters with interface types.
//
// TODO(mdempsky): Add the needed *runtime._type pointers into the
// rtypes section above instead, and omit itabs entries when we
// statically know it won't be needed.
assertOffset("itabs", dict.itabsOffset())
for _, info := range dict.itabs {
typ := pr.typIdx(info.typ, dict, true)
iface := pr.typIdx(info.iface, dict, true)
if !iface.IsInterface() {
ot += 3 * types.PtrSize
continue
}
ot = objw.SymPtr(lsym, ot, reflectdata.TypeLinksym(typ), 0)
ot = objw.SymPtr(lsym, ot, reflectdata.TypeLinksym(iface), 0)
if !typ.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() + 3*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())
}
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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)
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}
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
}
// TODO(mdempsky): Rethink this hack.
if strings.HasPrefix(name.Sym().Name, "~") || base.Flag.GenDwarfInl == 0 {
name.SetPos(r.inlCall.Pos())
name.SetInlFormal(false)
name.SetInlLocal(false)
}
}
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]
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// 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 {
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// 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)
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()
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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))
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}
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()
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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 {
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expr, def := r.assign()
lhs[i] = expr
if def {
names = append(names, expr.(*ir.Name))
}
}
return names, lhs
}
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// 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()
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setBasePos(pos)
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_, 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() {
rang := ir.NewRangeStmt(pos, nil, nil, nil, nil)
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)
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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)
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}
rang.Body = r.blockStmt()
r.closeAnotherScope()
return rang
}
pos := r.pos()
init := r.stmt()
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cond := r.optExpr()
post := r.stmt()
body := r.blockStmt()
r.closeAnotherScope()
stmt := ir.NewForStmt(pos, init, cond, post, body)
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()
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// "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...)
}
}
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// 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 := typecheck.Lookup(r.String())
ident = ir.NewIdent(pos, sym)
}
x := r.expr()
iface = x.Type()
tag = ir.NewTypeSwitchGuard(pos, ident, x)
} else {
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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()
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// 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() {