cmd/go: add go generate

First cut.

Works well enough to support yacc via
        https://golang.org/cl/125620044.

LGTM=alex.brainman, rsc
R=rsc, alex.brainman
CC=golang-codereviews
https://golang.org/cl/125580044

3 files changed, 32 insertions, 0 deletions

diff --git a/src/cmd/go/testdata/generate/test1.go b/src/cmd/go/testdata/generate/test1.go
new file mode 100644
index 0000000000..1f05734f04
--- /dev/null
+++ b/src/cmd/go/testdata/generate/test1.go
@@ -0,0 +1,13 @@
+// Copyright 2014 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.
+
+// Simple test for go generate.
+
+// We include a build tag that go generate should ignore.
+
+// +build ignore
+
+//go:generate echo Success
+
+package p
diff --git a/src/cmd/go/testdata/generate/test2.go b/src/cmd/go/testdata/generate/test2.go
new file mode 100644
index 0000000000..ef1a3d9515
--- /dev/null
+++ b/src/cmd/go/testdata/generate/test2.go
@@ -0,0 +1,10 @@
+// Copyright 2014 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 go generate handles command aliases.
+
+//go:generate -command run echo Now is the time
+//go:generate run for all good men
+
+package p
diff --git a/src/cmd/go/testdata/generate/test3.go b/src/cmd/go/testdata/generate/test3.go
new file mode 100644
index 0000000000..41ffb7ea87
--- /dev/null
+++ b/src/cmd/go/testdata/generate/test3.go
@@ -0,0 +1,9 @@
+// Copyright 2014 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 go generate variable substitution.
+
+//go:generate echo $GOARCH $GOFILE $GOPACKAGE xyz$GOPACKAGE/$GOFILE/123
+
+package p