From 7ea2116bdd43b10a4a7b181d14897a953f93b2c3 Mon Sep 17 00:00:00 2001
From: Dimi Racordon <dimitri.racordon@gmail.com>
Date: Wed, 6 Sep 2023 16:20:54 +0200
Subject: [PATCH] Implement a CLI to demangle symbols

---
 Package.swift                    |  7 +++++++
 Sources/hylo-demangle/main.swift | 24 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 Sources/hylo-demangle/main.swift

diff --git a/Package.swift b/Package.swift
index 3f7f89fa4..4c57c1ed6 100644
--- a/Package.swift
+++ b/Package.swift
@@ -51,6 +51,13 @@ let package = Package(
       ],
       swiftSettings: allTargetsSwiftSettings),
 
+    .executableTarget(
+      name: "hylo-demangle",
+      dependencies: [
+        "IR"
+      ],
+      swiftSettings: allTargetsSwiftSettings),
+
     .target(
       name: "Driver",
       dependencies: [
diff --git a/Sources/hylo-demangle/main.swift b/Sources/hylo-demangle/main.swift
new file mode 100644
index 000000000..98cefcf63
--- /dev/null
+++ b/Sources/hylo-demangle/main.swift
@@ -0,0 +1,24 @@
+import Foundation
+import IR
+
+/// Reports the given `diagnostic` on the standard error and exit with status -1.
+func error(_ diagnostic: String) -> Never {
+  let d = Data("\(diagnostic)\n".utf8)
+  FileHandle.standardError.write(d)
+  exit(-1)
+}
+
+func main() {
+  guard CommandLine.arguments.count > 1 else {
+    error("missing input")
+  }
+
+  let n = CommandLine.arguments[1]
+  guard let s = DemangledSymbol(n) else {
+    error("could not demangle '\(n)'")
+  }
+
+  print(s)
+}
+
+main()