strings: re-introduce noescape wrapper

CL 573955 added internal/abi:NoEscape function, and use it in strings
builder copyCheck code.

However, internal/abi is a runtime package, which can not be built with
-d=checkptr flag yet. This causes incorrect inlining decision, since
NoEscape must not be inlined when -d=checkptr is used.

Fixing this by re-introducing noescape wrapper.

Fixes #68415

Change-Id: I776cab4c9e9e4b3e58162dcce6ec025cb366bdee
Reviewed-on: https://go-review.googlesource.com/c/go/+/598295
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Jorropo <jorropo.pgm@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>

diff --git a/src/strings/builder.go b/src/strings/builder.go
index e6df08c6f479ad5c13efec91c3646b49335b48f4..3b37888cbf6dbae87d570a314d34cb3c5c6e5d14 100644 (file)
--- a/src/strings/builder.go
+++ b/src/strings/builder.go
@@ -23,6 +23,18 @@ type Builder struct {
        buf []byte
 }
 
+// This is just a wrapper around abi.NoEscape.
+//
+// This wrapper is necessary because internal/abi is a runtime package,
+// so it can not be built with -d=checkptr, causing incorrect inlining
+// decision when building with checkptr enabled, see issue #68415.
+//
+//go:nosplit
+//go:nocheckptr
+func noescape(p unsafe.Pointer) unsafe.Pointer {
+       return abi.NoEscape(p)
+}
+
 func (b *Builder) copyCheck() {
        if b.addr == nil {
                // This hack works around a failing of Go's escape analysis
@@ -30,7 +42,7 @@ func (b *Builder) copyCheck() {
                // See issue 23382.
                // TODO: once issue 7921 is fixed, this should be reverted to
                // just "b.addr = b".
-               b.addr = (*Builder)(abi.NoEscape(unsafe.Pointer(b)))
+               b.addr = (*Builder)(noescape(unsafe.Pointer(b)))
        } else if b.addr != b {
                panic("strings: illegal use of non-zero Builder copied by value")
        }

diff --git a/test/fixedbugs/issue68415.go b/test/fixedbugs/issue68415.go
new file mode 100644 (file)
index 0000000..cf278ac
--- /dev/null
+++ b/test/fixedbugs/issue68415.go
@@ -0,0 +1,15 @@
+// run -gcflags=all=-d=checkptr
+
+// Copyright 2024 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 main
+
+import "regexp"
+
+var dataFileRegexp = regexp.MustCompile(`^data\.\d+\.bin$`)
+
+func main() {
+       _ = dataFileRegexp
+}