cmd/link: increase the function call limit in stkcheck

ianlancetaylor · ianlancetaylor · commit 951143cf1425 · 2019-08-09T20:22:03.000Z
There is real (albeit generated) code that exceeds the limit. Fixes #33555 Change-Id: I668e85825d3d2a471970e869abe63f3492213cc1 Reviewed-on: https://go-review.googlesource.com/c/go/+/189697 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
@@ -2066,7 +2066,7 @@ func stkcheck(ctxt *Link, up *chain, depth int) int {
 		s.Attr |= sym.AttrStackCheck
 	}
 
-	if depth > 100 {
+	if depth > 500 {
 		Errorf(s, "nosplit stack check too deep")
 		stkbroke(ctxt, up, 0)
 		return -1
diff --git a/test/fixedbugs/issue33555.go b/test/fixedbugs/issue33555.go
@@ -0,0 +1,81 @@
+// +build !nacl,!js
+// run
+
+// Copyright 2019 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 that the linker permits long call sequences.
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+)
+
+const start = `
+package main
+
+func main() {
+	println(f0() + 1)
+}
+`
+
+const fn = `
+//go:noinline
+func f%d() int {
+	return f%d() + 1
+}`
+
+const fnlast = `
+//go:noinline
+func f%d() int {
+	return 0
+}
+`
+
+const count = 400
+
+func main() {
+	if err := test(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func test() error {
+	var buf bytes.Buffer
+	buf.WriteString(start)
+	for i := 0; i < count; i++ {
+		fmt.Fprintf(&buf, fn, i, i + 1)
+	}
+	fmt.Fprintf(&buf, fnlast, count)
+
+	dir, err := ioutil.TempDir("", "issue33555")
+	if err != nil {
+		return err
+	}
+	defer os.RemoveAll(dir)
+
+	fn := filepath.Join(dir, "x.go")
+	if err := ioutil.WriteFile(fn, buf.Bytes(), 0644); err != nil {
+		return err
+	}
+
+	out, err := exec.Command("go", "run", fn).CombinedOutput()
+	if err != nil {
+		return err
+	}
+
+	want := strconv.Itoa(count + 1)
+	if got := string(bytes.TrimSpace(out)); got != want {
+		return fmt.Errorf("got %q want %q", got, want)
+	}
+
+	return nil
+}

Original file line number	Diff line number	Diff line change
`@@ -2066,7 +2066,7 @@ func stkcheck(ctxt Link, up chain, depth int) int {`
`2066`	`2066`	`s.Attr \|= sym.AttrStackCheck`
`2067`	`2067`	`}`
`2068`	`2068`
`2069`		`- if depth > 100 {`
	`2069`	`+ if depth > 500 {`
`2070`	`2070`	`Errorf(s, "nosplit stack check too deep")`
`2071`	`2071`	`stkbroke(ctxt, up, 0)`
`2072`	`2072`	`return -1`