From 5d1b53a944a415205a945f4ddd89a0af8e9f114f Mon Sep 17 00:00:00 2001 From: David Lazar <lazard@golang.org> Date: Mon, 28 Nov 2016 17:39:31 -0500 Subject: [PATCH] cmd/compile: generate code that type checks when inlining variadic functions This fixes a bug in -l=3 or higher. To inline a variadic function, the compiler generates code that constructs a slice of arguments for the variadic parameter. Consider the function func Foo(xs ...string) and the call Foo("hello", "world"). To inline the call to Foo, the compiler used to generate xs := [2]string{"hello", "world"}[:] which doesn't type check: invalid operation [2]string literal[:] (slice of unaddressable value). Now, the compiler generates xs := []string{"hello", "world"} which does type check. Fixes #18116. Change-Id: I0ee531ef2e6cc276db6fb12602b25a46d6d5db21 Reviewed-on: https://go-review.googlesource.com/33671 Reviewed-by: Keith Randall <khr@golang.org> --- src/cmd/compile/internal/gc/inl.go | 5 ++--- test/inline_variadic.go | 19 +++++++++++++++++++ 2 files changed, 21 insertions(+), 3 deletions(-) create mode 100644 test/inline_variadic.go diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go index 59a047fdf250b8..d8f1f2453645c8 100644 --- a/src/cmd/compile/internal/gc/inl.go +++ b/src/cmd/compile/internal/gc/inl.go @@ -781,10 +781,9 @@ func mkinlcall1(n *Node, fn *Node, isddd bool) *Node { as.Right = nodnil() as.Right.Type = varargtype } else { - vararrtype := typArray(varargtype.Elem(), int64(varargcount)) - as.Right = nod(OCOMPLIT, nil, typenod(vararrtype)) + varslicetype := typSlice(varargtype.Elem()) + as.Right = nod(OCOMPLIT, nil, typenod(varslicetype)) as.Right.List.Set(varargs) - as.Right = nod(OSLICE, as.Right, nil) } as = typecheck(as, Etop) diff --git a/test/inline_variadic.go b/test/inline_variadic.go new file mode 100644 index 00000000000000..6466c2b093877d --- /dev/null +++ b/test/inline_variadic.go @@ -0,0 +1,19 @@ +// errorcheck -0 -m -l=3 + +// Copyright 2016 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. + +// Test more aggressive inlining (-l=3 allows variadic functions) +// See issue #18116. + +package foo + +func head(xs ...string) string { // ERROR "can inline head" "leaking param: xs to result" + return xs[0] +} + +func f() string { // ERROR "can inline f" + x := head("hello", "world") // ERROR "inlining call to head" "\[\]string literal does not escape" + return x +}