misc/cgo/testshared: rewrite in Go

And fix to work on filesystems with only 1s resolution.

Fixes #10724

Change-Id: Ia07463f090b4290fc27f5953fa94186463d7afc7
Reviewed-on: https://go-review.googlesource.com/9768Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

misc/cgo/testshared/test.bash

-#!/usr/bin/env bash
-# Copyright 2015 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.
-
-# Test that -buildmode=shared can produce a shared library and that
-# -linkshared can link against it to produce a working executable.
-
-set -eu
-
-
-die () {
-    echo $@
-    exit 1
-}
-
-# Because go install -buildmode=shared $standard_library_package always
-# installs into $GOROOT, here are some gymnastics to come up with a
-# unique installsuffix to use in this test that we can clean up
-# afterwards.
-rootdir="$(dirname $(go list -f '{{.Target}}' runtime))"
-template="${rootdir}_XXXXXXXX_dynlink"
-std_install_dir=$(mktemp -d "$template")
-
-scratch_dir=$(mktemp -d)
-cp -a . $scratch_dir
-opwd="$(pwd)"
-cd $scratch_dir
-export GOPATH="$(pwd)"
-
-cleanup () {
-    rm -rf $std_install_dir $scratch_dir
-}
-trap cleanup EXIT
-
-mysuffix=$(echo $std_install_dir | sed -e 's/.*_\([^_]*\)_dynlink/\1/')
-
-# This is the smallest set of packages we can link into a shared
-# library (runtime/cgo is built implicitly). Check they are built into
-# a library with the expected name.
-minpkgs="runtime sync/atomic"
-soname=libruntime,sync-atomic.so
-
-go install -installsuffix="$mysuffix" -buildmode=shared $minpkgs || die "install -buildmode=shared failed"
-
-if [ ! -f "$std_install_dir/$soname" ]; then
-    echo "$std_install_dir/$soname not found!"
-    exit 1
-fi
-
-# The install command should have created a "shlibname" file for the
-# listed packages (and runtime/cgo) indicating the name of the shared
-# library containing it.
-for pkg in $minpkgs runtime/cgo; do
-    if [ ! -f "$std_install_dir/$pkg.shlibname" ]; then
-        die "no shlibname file for $pkg"
-    fi
-    if [ "$(cat "$std_install_dir/$pkg.shlibname")" != "$soname" ]; then
-        die "shlibname file for $pkg has wrong contents"
-    fi
-done
-
-# Build a trivial program that links against the shared library we
-# just made and check it runs.
-go install -installsuffix="$mysuffix" -linkshared trivial || die "build -linkshared failed"
-./bin/trivial || die "./bin/trivial failed"
-
-# And check that it is actually dynamically linked against the library
-# we hope it is linked against.
-
-ensure_ldd () {
-    a="$(ldd $1)" || die "ldd $1 failed: $a"
-    { echo "$a" | grep -q "$2"; } || die "$1 does not appear to be linked against $2"
-}
-
-ensure_ldd ./bin/trivial $std_install_dir/$soname
-
-# Build a GOPATH package into a shared library that links against the above one.
-rootdir="$(dirname $(go list -installsuffix="$mysuffix" -linkshared -f '{{.Target}}' dep))"
-go install -installsuffix="$mysuffix" -buildmode=shared -linkshared dep
-ensure_ldd $rootdir/libdep.so $std_install_dir/$soname
-
-
-# And exe that links against both
-go install -installsuffix="$mysuffix" -linkshared exe
-./bin/exe || die "./bin/exe failed with code $?"
-ensure_ldd ./bin/exe $rootdir/libdep.so
-ensure_ldd ./bin/exe $std_install_dir/$soname
-
-# Now, test rebuilding of shared libraries when they are stale.
-
-will_check_rebuilt () {
-    for f in $@; do cp $f $f.bak; done
-}
-
-assert_rebuilt () {
-    find $1 -newer $1.bak | grep -q . || die "$1 was not rebuilt"
-}
-
-assert_not_rebuilt () {
-    find $1 -newer $1.bak | grep  . && die "$1 was rebuilt" || true
-}
-
-# If the source is newer than both the .a file and the .so, both are rebuilt.
-touch src/dep/dep.go
-will_check_rebuilt $rootdir/libdep.so $rootdir/dep.a
-go install -installsuffix="$mysuffix" -linkshared exe
-assert_rebuilt $rootdir/dep.a
-assert_rebuilt $rootdir/libdep.so
-
-# If the .a file is newer than the .so, the .so is rebuilt (but not the .a)
-touch $rootdir/dep.a
-will_check_rebuilt $rootdir/libdep.so $rootdir/dep.a
-go install  -installsuffix="$mysuffix" -linkshared exe
-assert_not_rebuilt $rootdir/dep.a
-assert_rebuilt $rootdir/libdep.so
-
-# If we make an ABI-breaking change to dep and rebuild libp.so but not exe, exe will
-# abort with a complaint on startup.
-# This assumes adding an exported function breaks ABI, which is not true in some
-# senses but suffices for the narrow definition of ABI compatiblity the toolchain
-# uses today.
-echo "func ABIBreak() {}" >> src/dep/dep.go
-go install -installsuffix="$mysuffix" -buildmode=shared -linkshared dep
-output="$(./bin/exe 2>&1)" && die "exe succeeded after ABI break" || true
-msg="abi mismatch detected between the executable and libdep.so"
-{ echo "$output" | grep -q "$msg"; } || die "exe did not fail with expected message"
-
-# Rebuilding exe makes it work again.
-go install -installsuffix="$mysuffix" -linkshared exe
-./bin/exe || die "exe failed after rebuild"
-
-# If we make a change which does not break ABI (such as adding an
-# unexported function) and rebuild libdep.so, exe still works.
-echo "func noABIBreak() {}" >> src/dep/dep.go
-go install -installsuffix="$mysuffix" -buildmode=shared -linkshared dep
-./bin/exe || die "exe failed after non-ABI breaking change"

src/cmd/dist/test.go

@@ -324,7 +324,7 @@ func (t *tester) registerTests() {
 			t.registerTest("testcshared", "../misc/cgo/testcshared", "./test.bash")
 		}
 		if t.supportedBuildmode("shared") {
-			t.registerTest("testshared", "../misc/cgo/testshared", "./test.bash")
+			t.registerTest("testshared", "../misc/cgo/testshared", "go", "test")
 		}
 		if t.gohostos == "linux" && t.goarch == "amd64" {
 			t.registerTest("testasan", "../misc/cgo/testasan", "go", "run", "main.go")