cmd/cgo: enable #cgo noescape/nocallback

In Go 1.22 we added code to the go/build package to ignore #cgo noescape
and nocallback directives. That permits us to enable these directives in Go 1.24.

Also, this fixed a Bug in CL 497837:
After retiring _Cgo_use for parameters, the compiler will treat the
parameters, start from the second, as non-alive. Then, they will be marked
as scalar in stackmap, which means the pointer won't be copied correctly
in copystack.

Fixes #56378.
Fixes #63739.

Change-Id: I46e773240f8a467c3c4ba201dc5b4ee473cf6e3e
GitHub-Last-Rev: 42fcc506d6a7681ef24ac36a5904b57bda4b15cd
GitHub-Pull-Request: golang/go#66879
Reviewed-on: https://go-review.googlesource.com/c/go/+/579955
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

3 files changed, 63 insertions, 2 deletions

diff --git a/src/runtime/testdata/testprogcgo/cgonocallback.go b/src/runtime/testdata/testprogcgo/cgonocallback.go
index c13bf271a4..8cbbfd1957 100644
--- a/src/runtime/testdata/testprogcgo/cgonocallback.go
+++ b/src/runtime/testdata/testprogcgo/cgonocallback.go
@@ -8,7 +8,8 @@ package main
 // But it do callback to go in this test, Go should crash here.
 
 /*
-// TODO(#56378): #cgo nocallback runCShouldNotCallback
+#cgo nocallback runCShouldNotCallback
+
 extern void runCShouldNotCallback();
 */
 import "C"
diff --git a/src/runtime/testdata/testprogcgo/cgonoescape.go b/src/runtime/testdata/testprogcgo/cgonoescape.go
index f5eebac677..2b7c7a9c55 100644
--- a/src/runtime/testdata/testprogcgo/cgonoescape.go
+++ b/src/runtime/testdata/testprogcgo/cgonoescape.go
@@ -13,7 +13,8 @@ package main
 // 2. less than 100 new allocated heap objects after invoking withoutNoEscape 100 times.
 
 /*
-// TODO(#56378): #cgo noescape runCWithNoEscape
+#cgo noescape runCWithNoEscape
+#cgo nocallback runCWithNoEscape
 
 void runCWithNoEscape(void *p) {
 }
diff --git a/src/runtime/testdata/testprogcgo/issue63739.go b/src/runtime/testdata/testprogcgo/issue63739.go
new file mode 100644
index 0000000000..dbe37b6d0e
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/issue63739.go
@@ -0,0 +1,59 @@
+// 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 main
+
+// This is for issue #63739.
+// Ensure that parameters are kept alive until the end of the C call. If not,
+// then a stack copy at just the right time while calling into C might think
+// that any stack pointers are not alive and fail to update them, causing the C
+// function to see the old, no longer correct, pointer values.
+
+/*
+int add_from_multiple_pointers(int *a, int *b, int *c) {
+	*a = *a + 1;
+	*b = *b + 1;
+	*c = *c + 1;
+	return *a + *b + *c;
+}
+#cgo noescape add_from_multiple_pointers
+#cgo nocallback add_from_multiple_pointers
+*/
+import "C"
+
+import (
+	"fmt"
+)
+
+const (
+	maxStack = 1024
+)
+
+func init() {
+	register("CgoEscapeWithMultiplePointers", CgoEscapeWithMultiplePointers)
+}
+
+func CgoEscapeWithMultiplePointers() {
+	stackGrow(maxStack)
+	fmt.Println("OK")
+}
+
+//go:noinline
+func testCWithMultiplePointers() {
+	var a C.int = 1
+	var b C.int = 2
+	var c C.int = 3
+	v := C.add_from_multiple_pointers(&a, &b, &c)
+	if v != 9 || a != 2 || b != 3 || c != 4 {
+		fmt.Printf("%d + %d + %d != %d\n", a, b, c, v)
+	}
+}
+
+func stackGrow(n int) {
+	if n == 0 {
+		return
+	}
+	testCWithMultiplePointers()
+	stackGrow(n - 1)
+}