From e572218d1273bf54bf8cafd39f93f22de196dd55 Mon Sep 17 00:00:00 2001 From: Alberto Donizetti Date: Sat, 26 Sep 2020 09:42:59 +0200 Subject: [PATCH] cmd/compile: fix escape reason for MAKESLICE with no cap When explaining why the slice from a make() call escapes for the -m -m message, we print "non-const size" if any one of Isconst(n.Left) and Isconst(n.Right) return false; but for OMAKESLICE nodes with no cap, n.Right is nil, so Isconst(n.Right, CTINT) will be always false. Only call Isconst on n.Right if it's not nil. Fixes #41635 Change-Id: I8729801a9b234b68ae40adad64d66fa7653adf09 Reviewed-on: https://go-review.googlesource.com/c/go/+/257641 Reviewed-by: Cuong Manh Le Reviewed-by: Keith Randall Trust: Alberto Donizetti --- src/cmd/compile/internal/gc/escape.go | 2 +- test/fixedbugs/issue41635.go | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue41635.go diff --git a/src/cmd/compile/internal/gc/escape.go b/src/cmd/compile/internal/gc/escape.go index f435d8ff6a..d79d32ec48 100644 --- a/src/cmd/compile/internal/gc/escape.go +++ b/src/cmd/compile/internal/gc/escape.go @@ -1053,7 +1053,7 @@ func (e *Escape) newLoc(n *Node, transient bool) *EscLocation { if mustHeapAlloc(n) { why := "too large for stack" - if n.Op == OMAKESLICE && (!Isconst(n.Left, CTINT) || !Isconst(n.Right, CTINT)) { + if n.Op == OMAKESLICE && (!Isconst(n.Left, CTINT) || (n.Right != nil && !Isconst(n.Right, CTINT))) { why = "non-constant size" } e.flow(e.heapHole().addr(n, why), loc) diff --git a/test/fixedbugs/issue41635.go b/test/fixedbugs/issue41635.go new file mode 100644 index 0000000000..b33c1a07e7 --- /dev/null +++ b/test/fixedbugs/issue41635.go @@ -0,0 +1,18 @@ +//errorcheck -0 -m -m + +// Copyright 2020 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. + +package p + +func f() { // ERROR "" + b1 := make([]byte, 1<<17) // ERROR "too large for stack" "" + b2 := make([]byte, 100, 1<<17) // ERROR "too large for stack" "" + + n, m := 100, 200 + b1 = make([]byte, n) // ERROR "non-constant size" "" + b2 = make([]byte, 100, m) // ERROR "non-constant size" "" + + _, _ = b1, b2 +} -- 2.48.1