env: find llgo root for development

compiler/internal/env/version.go

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package env
+
+import "runtime/debug"
+
+// buildVersion is the LLGo tree's version string at build time. It should be
+// set by the linker.
+var buildVersion string
+
+// Version returns the version of the running LLGo binary.
+//
+//export LLGoVersion
+func Version() string {
+	if buildVersion != "" {
+		return buildVersion
+	}
+	info, ok := debug.ReadBuildInfo()
+	if ok {
+		return info.Main.Version
+	}
+	return "(devel)"
+}
+
+func Devel() bool {
+	return Version() == "(devel)"
+}