gcc/libgo/go/bytes/boundary_test.go
Ian Lance Taylor 1a2f01efa6 libgo: update to Go1.10beta1
Update the Go library to the 1.10beta1 release.
    
    Requires a few changes to the compiler for modifications to the map
    runtime code, and to handle some nowritebarrier cases in the runtime.
    
    Reviewed-on: https://go-review.googlesource.com/86455

gotools/:
	* Makefile.am (go_cmd_vet_files): New variable.
	(go_cmd_buildid_files, go_cmd_test2json_files): New variables.
	(s-zdefaultcc): Change from constants to functions.
	(noinst_PROGRAMS): Add vet, buildid, and test2json.
	(cgo$(EXEEXT)): Link against $(LIBGOTOOL).
	(vet$(EXEEXT)): New target.
	(buildid$(EXEEXT)): New target.
	(test2json$(EXEEXT)): New target.
	(install-exec-local): Install all $(noinst_PROGRAMS).
	(uninstall-local): Uninstasll all $(noinst_PROGRAMS).
	(check-go-tool): Depend on $(noinst_PROGRAMS).  Copy down
	objabi.go.
	(check-runtime): Depend on $(noinst_PROGRAMS).
	(check-cgo-test, check-carchive-test): Likewise.
	(check-vet): New target.
	(check): Depend on check-vet.  Look at cmd_vet-testlog.
	(.PHONY): Add check-vet.
	* Makefile.in: Rebuild.

From-SVN: r256365
2018-01-09 01:23:08 +00:00

85 lines
2.1 KiB
Go

// Copyright 2017 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.
//
// +build linux
package bytes_test
import (
. "bytes"
"syscall"
"testing"
)
// This file tests the situation where byte operations are checking
// data very near to a page boundary. We want to make sure those
// operations do not read across the boundary and cause a page
// fault where they shouldn't.
// These tests run only on linux. The code being tested is
// not OS-specific, so it does not need to be tested on all
// operating systems.
// dangerousSlice returns a slice which is immediately
// preceded and followed by a faulting page.
func dangerousSlice(t *testing.T) []byte {
pagesize := syscall.Getpagesize()
b, err := syscall.Mmap(0, 0, 3*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)
if err != nil {
t.Fatalf("mmap failed %s", err)
}
err = syscall.Mprotect(b[:pagesize], syscall.PROT_NONE)
if err != nil {
t.Fatalf("mprotect low failed %s\n", err)
}
err = syscall.Mprotect(b[2*pagesize:], syscall.PROT_NONE)
if err != nil {
t.Fatalf("mprotect high failed %s\n", err)
}
return b[pagesize : 2*pagesize]
}
func TestEqualNearPageBoundary(t *testing.T) {
t.Parallel()
b := dangerousSlice(t)
for i := range b {
b[i] = 'A'
}
for i := 0; i <= len(b); i++ {
Equal(b[:i], b[len(b)-i:])
Equal(b[len(b)-i:], b[:i])
}
}
func TestIndexByteNearPageBoundary(t *testing.T) {
t.Parallel()
b := dangerousSlice(t)
for i := range b {
idx := IndexByte(b[i:], 1)
if idx != -1 {
t.Fatalf("IndexByte(b[%d:])=%d, want -1\n", i, idx)
}
}
}
func TestIndexNearPageBoundary(t *testing.T) {
t.Parallel()
var q [64]byte
b := dangerousSlice(t)
if len(b) > 256 {
// Only worry about when we're near the end of a page.
b = b[len(b)-256:]
}
for j := 1; j < len(q); j++ {
q[j-1] = 1 // difference is only found on the last byte
for i := range b {
idx := Index(b[i:], q[:j])
if idx != -1 {
t.Fatalf("Index(b[%d:], q[:%d])=%d, want -1\n", i, j, idx)
}
}
q[j-1] = 0
}
}