switch to CGO-free builds

vendor/modernc.org/memory/mmap_openbsd.go

@@ -0,0 +1,97 @@
+// Copyright 2011 Evan Shaw. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE-MMAP-GO file.
+
+// Modifications (c) 2024 The Memory Authors.
+// Copyright 2024 The Memory Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build openbsd && (386 || amd64 || arm64)
+
+package memory
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// track what can be unmapped
+var allocmap map[uintptr][]byte
+var m sync.Mutex
+
+const pageSizeLog = 20
+
+var (
+	osPageMask = osPageSize - 1
+	osPageSize = os.Getpagesize()
+)
+
+func init() {
+	allocmap = make(map[uintptr][]byte)
+}
+
+func unmap(addr uintptr, size int) error {
+	if trace {
+		fmt.Fprintf(os.Stderr, "unmap %#x\n", addr)
+	}
+
+	a, ok := allocmap[addr]
+	if !ok {
+		if trace {
+			fmt.Fprintf(os.Stderr, "unmap %#x: not found\n", addr)
+		}
+		// panic("unmap called on unknown mapping")
+		return nil
+	}
+
+	if err := unix.Munmap(a); err != nil {
+		if trace {
+			fmt.Fprintf(os.Stderr, "unmap: %s\n", err.Error())
+		}
+		// panic(err.Error())
+		return err
+	}
+
+	m.Lock()
+	delete(allocmap, addr)
+	m.Unlock()
+
+	return nil
+}
+
+func mmap(size int) (uintptr, int, error) {
+	roundsize := roundup(size, osPageSize) + pageSize
+
+	b, err := unix.Mmap(-1, 0, roundsize, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_PRIVATE|unix.MAP_ANON)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	p := uintptr(unsafe.Pointer(&b[0]))
+
+	if trace {
+		fmt.Fprintf(os.Stderr, "mmap actual @%#x size: %#x\n", p, roundsize)
+	}
+
+	// waste all the space until the next page
+	r := (p + uintptr(pageSize)) &^ uintptr(pageMask)
+	nsize := (roundsize) - int((r - p))
+	if nsize < size {
+		panic("didn't allocate enough to meet initial request!")
+	}
+
+	if trace {
+		fmt.Fprintf(os.Stderr, "mmap page-rounded @%#x size: %#x\n", r, nsize)
+	}
+
+	m.Lock()
+	allocmap[r] = b
+	m.Unlock()
+
+	return r, nsize, nil
+}