day1v0.0.1

1 files changed, 33 insertions, 0 deletions

diff --git a/abi/escape.go b/abi/escape.go
new file mode 100644
index 0000000..8cdae14
--- /dev/null
+++ b/abi/escape.go
@@ -0,0 +1,33 @@
+// 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 abi
+
+import "unsafe"
+
+// NoEscape hides the pointer p from escape analysis, preventing it
+// from escaping to the heap. It compiles down to nothing.
+//
+// WARNING: This is very subtle to use correctly. The caller must
+// ensure that it's truly safe for p to not escape to the heap by
+// maintaining runtime pointer invariants (for example, that globals
+// and the heap may not generally point into a stack).
+//
+//go:nosplit
+//go:nocheckptr
+func NoEscape(p unsafe.Pointer) unsafe.Pointer {
+	x := uintptr(p)
+	return unsafe.Pointer(x ^ 0)
+}
+
+var alwaysFalse bool
+var escapeSink any
+
+// Escape forces any pointers in x to escape to the heap.
+func Escape[T any](x T) T {
+	if alwaysFalse {
+		escapeSink = x
+	}
+	return x
+}