// paramName replaces incompatible name with a p0-pN name.
// Missing names, or existing names of the form p[0-9] are incompatible.
// TODO(crawshaw): Replace invalid unicode names.
func paramName(params *types.Tuple, pos int) string {
	name := params.At(pos).Name()
	if name == "" || name == "_" || paramRE.MatchString(name) {
		name = fmt.Sprintf("p%d", pos)
	}
	return name
}

func (p *exporter) tuple(t *types.Tuple) {
	n := t.Len()
	p.int(n)
	for i := 0; i < n; i++ {
		p.param(t.At(i))
	}
}

func (h Hasher) hashTuple(tuple *types.Tuple) uint32 {
	// See go/types.identicalTypes for rationale.
	n := tuple.Len()
	var hash uint32 = 9137 + 2*uint32(n)
	for i := 0; i < n; i++ {
		hash += 3 * h.Hash(tuple.At(i).Type())
	}
	return hash
}

func (sym *symtab) processTuple(tuple *types.Tuple) {
	if tuple == nil {
		return
	}
	for i := 0; i < tuple.Len(); i++ {
		ivar := tuple.At(i)
		ityp := ivar.Type()
		isym := sym.symtype(ityp)
		if isym == nil {
			sym.addType(ivar, ityp)
		}
	}
}

func (p *printer) writeTuple(this *types.Package, tup *types.Tuple, variadic bool, visited []types.Type) {
	p.print("(")
	for i, n := 0, tup.Len(); i < n; i++ {
		if i > 0 {
			p.print(", ")
		}
		v := tup.At(i)
		if name := v.Name(); name != "" {
			p.print(name)
			p.print(" ")
		}
		typ := v.Type()
		if variadic && i == n-1 {
			p.print("...")
			typ = typ.(*types.Slice).Elem()
		}
		p.writeTypeInternal(this, typ, visited)
	}
	p.print(")")
}

func newVars(tuple *types.Tuple) []*Var {
	vars := make([]*Var, 0, tuple.Len())
	for i := 0; i < tuple.Len(); i++ {
		vars = append(vars, newVar(tuple.At(i)))
	}
	return vars
}

func (g *goGen) tupleString(tuple *types.Tuple) string {
	n := tuple.Len()
	if n <= 0 {
		return ""
	}

	str := make([]string, 0, n)
	for i := 0; i < tuple.Len(); i++ {
		v := tuple.At(i)
		n := v.Name()
		typ := v.Type()
		str = append(str, n+" "+g.qualifiedType(typ))
	}

	return strings.Join(str, ", ")
}

func (fr *frame) setupUnwindBlock(rec *ssa.BasicBlock, results *types.Tuple) {
	recoverbb := llvm.AddBasicBlock(fr.function, "")
	if rec != nil {
		fr.translateBlock(rec, recoverbb)
	} else if results.Len() == 0 || results.At(0).Anonymous() {
		// TODO(pcc): Remove this code after https://codereview.appspot.com/87210044/ lands
		fr.builder.SetInsertPointAtEnd(recoverbb)
		values := make([]llvm.Value, results.Len())
		for i := range values {
			values[i] = llvm.ConstNull(fr.llvmtypes.ToLLVM(results.At(i).Type()))
		}
		fr.retInf.encode(llvm.GlobalContext(), fr.allocaBuilder, fr.builder, values)
	} else {
		fr.builder.SetInsertPointAtEnd(recoverbb)
		fr.builder.CreateUnreachable()
	}

	checkunwindbb := llvm.AddBasicBlock(fr.function, "")
	fr.builder.SetInsertPointAtEnd(checkunwindbb)
	exc := fr.createLandingPad(true)
	fr.runDefers()

	frame := fr.builder.CreateLoad(fr.frameptr, "")
	shouldresume := fr.builder.CreateIsNull(frame, "")

	resumebb := llvm.AddBasicBlock(fr.function, "")
	fr.builder.CreateCondBr(shouldresume, resumebb, recoverbb)

	fr.builder.SetInsertPointAtEnd(resumebb)
	fr.builder.CreateResume(exc)

	fr.builder.SetInsertPointAtEnd(fr.unwindBlock)
	fr.createLandingPad(false)
	fr.runtime.checkDefer.invoke(fr, checkunwindbb, fr.frameptr)
	fr.runDefers()
	fr.builder.CreateBr(recoverbb)
}