libgo: update to Go 1.8 release candidate 1

    
    Compiler changes:
      * Change map assignment to use mapassign and assign value directly.
      * Change string iteration to use decoderune, faster for ASCII strings.
      * Change makeslice to take int, and use makeslice64 for larger values.
      * Add new noverflow field to hmap struct used for maps.
    
    Unresolved problems, to be fixed later:
      * Commented out test in go/types/sizes_test.go that doesn't compile.
      * Commented out reflect.TestStructOf test for padding after zero-sized field.
    
    Reviewed-on: https://go-review.googlesource.com/35231

gotools/:
	Updates for Go 1.8rc1.
	* Makefile.am (go_cmd_go_files): Add bug.go.
	(s-zdefaultcc): Write defaultPkgConfig.
	* Makefile.in: Rebuild.

From-SVN: r244456

1 files changed, 73 insertions, 0 deletions

diff --git a/libgo/go/plugin/plugin.go b/libgo/go/plugin/plugin.go
new file mode 100644
index 0000000..b86099a
--- /dev/null
+++ b/libgo/go/plugin/plugin.go
@@ -0,0 +1,73 @@
+// Copyright 2016 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 plugin implements loading and symbol resolution of Go plugins.
+//
+// Currently plugins only work on Linux.
+//
+// A plugin is a Go main package with exported functions and variables that
+// has been built with:
+//
+//	go build -buildmode=plugin
+//
+// When a plugin is first opened, the init functions of all packages not
+// already part of the program are called. The main function is not run.
+// A plugin is only initialized once, and cannot be closed.
+package plugin
+
+// Plugin is a loaded Go plugin.
+type Plugin struct {
+	pluginpath string
+	loaded     chan struct{} // closed when loaded
+	syms       map[string]interface{}
+}
+
+// Open opens a Go plugin.
+// If a path has already been opened, then the existing *Plugin is returned.
+// It is safe for concurrent use by multiple goroutines.
+func Open(path string) (*Plugin, error) {
+	return open(path)
+}
+
+// Lookup searches for a symbol named symName in plugin p.
+// A symbol is any exported variable or function.
+// It reports an error if the symbol is not found.
+// It is safe for concurrent use by multiple goroutines.
+func (p *Plugin) Lookup(symName string) (Symbol, error) {
+	return lookup(p, symName)
+}
+
+// A Symbol is a pointer to a variable or function.
+//
+// For example, a plugin defined as
+//
+//	package main
+//
+//	// // No C code needed.
+//	import "C"
+//
+//	import "fmt"
+//
+//	var V int
+//
+//	func F() { fmt.Printf("Hello, number %d\n", V) }
+//
+// may be loaded with the Open function and then the exported package
+// symbols V and F can be accessed
+//
+//	p, err := plugin.Open("plugin_name.so")
+//	if err != nil {
+//		panic(err)
+//	}
+//	v, err := p.Lookup("V")
+//	if err != nil {
+//		panic(err)
+//	}
+//	f, err := p.Lookup("F")
+//	if err != nil {
+//		panic(err)
+//	}
+//	*v.(*int) = 7
+//	f.(func())() // prints "Hello, number 7"
+type Symbol interface{}