cmd: add "llgo version" command

xtool/env/build.go

@@ -0,0 +1,38 @@
+/*
+ * 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"
+
+// buildTime is the LLGo binary's build time. It should be set by the linker.
+var buildTime string
+
+// BuildTime returns the build time of the running LLGo binary.
+func BuildTime() string {
+	if buildTime != "" {
+		return buildTime
+	}
+	info, ok := debug.ReadBuildInfo()
+	if ok {
+		for _, setting := range info.Settings {
+			if setting.Key == "vcs.time" {
+				return setting.Value
+			}
+		}
+	}
+	return ""
+}

xtool/env/version.go

@@ -0,0 +1,35 @@
+/*
+ * 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.
+func Version() string {
+	if buildVersion != "" {
+		return buildVersion
+	}
+	info, ok := debug.ReadBuildInfo()
+	if ok {
+		return info.Main.Version
+	}
+	return "(devel)"
+}