go.tools/ssa: fix builder crash in select { case n, _ := <-c: ... }.
Cause: emitExtract requires a type for each component of the receive tuple; blank supplies no such type. Solution: remove type parameter for emitExtract as it is no longer needed: since rev b75cc03b4a56 it is always identical to the tuple.Type().At(index). + tests. Fixes golang/go#6806. R=gri, gri CC=axwalk, golang-dev https://golang.org/cl/30410043
This commit is contained in:
Alan Donovan
parent
8f1fdf33de
commit
cf7368c879
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@ -855,7 +855,7 @@ func (b *builder) emitCallArgs(fn *Function, sig *types.Signature, e *ast.CallEx
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v := b.expr(fn, arg)
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if ttuple, ok := v.Type().(*types.Tuple); ok { // MRV chain
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for i, n := 0, ttuple.Len(); i < n; i++ {
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args = append(args, emitExtract(fn, v, i, ttuple.At(i).Type()))
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args = append(args, emitExtract(fn, v, i))
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}
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} else {
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args = append(args, v)
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@ -955,12 +955,11 @@ func (b *builder) localValueSpec(fn *Function, spec *ast.ValueSpec) {
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default:
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// e.g. var x, y = pos()
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tuple := b.exprN(fn, spec.Values[0])
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result := tuple.Type().(*types.Tuple)
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for i, id := range spec.Names {
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if !isBlankIdent(id) {
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fn.addLocalForIdent(id)
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lhs := b.addr(fn, id, false) // non-escaping
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lhs.store(fn, emitExtract(fn, tuple, i, result.At(i).Type()))
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lhs.store(fn, emitExtract(fn, tuple, i))
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}
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}
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}
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@ -1012,9 +1011,8 @@ func (b *builder) assignStmt(fn *Function, lhss, rhss []ast.Expr, isDef bool) {
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} else {
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// e.g. x, y = pos()
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tuple := b.exprN(fn, rhss[0])
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result := tuple.Type().(*types.Tuple)
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for i, lval := range lvals {
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lval.store(fn, emitExtract(fn, tuple, i, result.At(i).Type()))
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lval.store(fn, emitExtract(fn, tuple, i))
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}
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}
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}
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@ -1307,8 +1305,8 @@ func (b *builder) typeSwitchStmt(fn *Function, s *ast.TypeSwitchStmt, label *lbl
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ti = x
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} else {
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yok := emitTypeTest(fn, x, casetype, cc.Case)
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ti = emitExtract(fn, yok, 0, casetype)
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condv = emitExtract(fn, yok, 1, tBool)
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ti = emitExtract(fn, yok, 0)
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condv = emitExtract(fn, yok, 1)
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}
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emitIf(fn, condv, body, next)
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fn.currentBlock = next
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@ -1451,7 +1449,7 @@ func (b *builder) selectStmt(fn *Function, s *ast.SelectStmt, label *lblock) {
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sel.setType(types.NewTuple(vars...))
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fn.emit(sel)
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idx := emitExtract(fn, sel, 0, tInt)
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idx := emitExtract(fn, sel, 0)
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done := fn.newBasicBlock("select.done")
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if label != nil {
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@ -1478,7 +1476,7 @@ func (b *builder) selectStmt(fn *Function, s *ast.SelectStmt, label *lblock) {
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switch comm := clause.Comm.(type) {
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case *ast.ExprStmt: // <-ch
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if debugInfo {
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v := emitExtract(fn, sel, r, vars[r].Type())
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v := emitExtract(fn, sel, r)
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emitDebugRef(fn, states[state].DebugNode.(ast.Expr), v, false)
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}
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r++
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@ -1488,7 +1486,7 @@ func (b *builder) selectStmt(fn *Function, s *ast.SelectStmt, label *lblock) {
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fn.addLocalForIdent(comm.Lhs[0].(*ast.Ident))
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}
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x := b.addr(fn, comm.Lhs[0], false) // non-escaping
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v := emitExtract(fn, sel, r, vars[r].Type())
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v := emitExtract(fn, sel, r)
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if debugInfo {
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emitDebugRef(fn, states[state].DebugNode.(ast.Expr), v, false)
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}
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@ -1499,7 +1497,7 @@ func (b *builder) selectStmt(fn *Function, s *ast.SelectStmt, label *lblock) {
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fn.addLocalForIdent(comm.Lhs[1].(*ast.Ident))
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}
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ok := b.addr(fn, comm.Lhs[1], false) // non-escaping
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ok.store(fn, emitExtract(fn, sel, 1, deref(ok.typ())))
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ok.store(fn, emitExtract(fn, sel, 1))
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}
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r++
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}
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@ -1717,14 +1715,14 @@ func (b *builder) rangeIter(fn *Function, x Value, tk, tv types.Type, pos token.
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body := fn.newBasicBlock("rangeiter.body")
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done = fn.newBasicBlock("rangeiter.done")
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emitIf(fn, emitExtract(fn, okv, 0, tBool), body, done)
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emitIf(fn, emitExtract(fn, okv, 0), body, done)
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fn.currentBlock = body
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if tk != tInvalid {
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k = emitExtract(fn, okv, 1, tk)
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k = emitExtract(fn, okv, 1)
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}
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if tv != tInvalid {
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v = emitExtract(fn, okv, 2, tv)
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v = emitExtract(fn, okv, 2)
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}
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return
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}
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@ -1763,10 +1761,10 @@ func (b *builder) rangeChan(fn *Function, x Value, tk types.Type, pos token.Pos)
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ko := fn.emit(recv)
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body := fn.newBasicBlock("rangechan.body")
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done = fn.newBasicBlock("rangechan.done")
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emitIf(fn, emitExtract(fn, ko, 1, tBool), body, done)
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emitIf(fn, emitExtract(fn, ko, 1), body, done)
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fn.currentBlock = body
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if tk != nil {
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k = emitExtract(fn, ko, 0, tk)
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k = emitExtract(fn, ko, 0)
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}
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return
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}
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@ -1952,7 +1950,7 @@ start:
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ttuple := tuple.Type().(*types.Tuple)
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for i, n := 0, ttuple.Len(); i < n; i++ {
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results = append(results,
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emitConv(fn, emitExtract(fn, tuple, i, ttuple.At(i).Type()),
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emitConv(fn, emitExtract(fn, tuple, i),
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fn.Signature.Results().At(i).Type()))
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}
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} else {
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@ -2239,13 +2237,11 @@ func (p *Package) Build() {
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} else {
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// n:1 initialization: var x, y := f()
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tuple := b.exprN(init, varinit.Rhs)
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result := tuple.Type().(*types.Tuple)
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for i, v := range varinit.Lhs {
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if v.Name() == "_" {
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continue
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}
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emitStore(init, p.values[v].(*Global),
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emitExtract(init, tuple, i, result.At(i).Type()))
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emitStore(init, p.values[v].(*Global), emitExtract(init, tuple, i))
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}
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}
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}
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11
ssa/emit.go
11
ssa/emit.go
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@ -268,14 +268,11 @@ func emitIf(f *Function, cond Value, tblock, fblock *BasicBlock) {
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}
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// emitExtract emits to f an instruction to extract the index'th
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// component of tuple, ascribing it type typ. It returns the
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// extracted value.
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// component of tuple. It returns the extracted value.
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//
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func emitExtract(f *Function, tuple Value, index int, typ types.Type) Value {
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func emitExtract(f *Function, tuple Value, index int) Value {
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e := &Extract{Tuple: tuple, Index: index}
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// In all cases but one (tSelect's recv), typ is redundant w.r.t.
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// tuple.Type().(*types.Tuple).Values[index].Type.
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e.setType(typ)
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e.setType(tuple.Type().(*types.Tuple).At(index).Type())
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return f.emit(e)
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}
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@ -329,7 +326,7 @@ func emitTailCall(f *Function, call *Call) {
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ret.Results = []Value{tuple}
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default:
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for i := 0; i < nr; i++ {
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v := emitExtract(f, tuple, i, tresults.At(i).Type())
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v := emitExtract(f, tuple, i)
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// TODO(adonovan): in principle, this is required:
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// v = emitConv(f, o.Type, f.Signature.Results[i].Type)
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// but in practice emitTailCall is only used when
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@ -571,3 +571,28 @@ func init() {
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panic(ints)
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}
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}
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func init() {
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// Regression test for issue 6806.
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ch := make(chan int)
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select {
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case n, _ := <-ch:
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_ = n
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default:
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// The default case disables the simplification of
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// select to a simple receive statement.
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}
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// value,ok-form receive where TypeOf(ok) is a named boolean.
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type mybool bool
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var x int
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var y mybool
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select {
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case x, y = <-ch:
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default:
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// The default case disables the simplification of
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// select to a simple receive statement.
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}
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_ = x
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_ = y
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}
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