TSCUtility: support additional spellings for ARM

ARM uses `armv[4-9]-?[arm]` as the arch field to encode the ISA
version and the core type for ARMv7.  Use the custom parsing logic
similar to the other fields to accommodate the spelling.

Author: compnerd

Sources/TSCUtility/Triple.swift

@@ -36,7 +36,7 @@ public struct Triple: Encodable, Equatable {
         case unknownOS(os: String)
     }
 
-    public enum Arch: String, Encodable {
+    public enum Arch: String, Encodable, CaseIterable {
         case x86_64
         case x86_64h
         case i686
@@ -135,6 +135,11 @@ public struct Triple: Encodable, Equatable {
         self.abiVersion = abiVersion
     }
 
+    fileprivate static func parseArch(_ string: String) -> Arch? {
+        var candidates = Arch.allCases.map { (name: $0.rawValue, value: $0) }
+        return candidates.first(where: { string.hasPrefix($0.name) })?.value
+    }
+
     fileprivate static func parseOS(_ string: String) -> OS? {
         var candidates =  OS.allCases.map{ (name: $0.rawValue, value: $0) }
         // LLVM target triples support this alternate spelling as well.
@@ -201,6 +206,7 @@ public struct Triple: Encodable, Equatable {
                 fatalError("Failed to get target info (\(error))")
             #endif
         }
+
         // Parse the compiler's JSON output.
         let parsedTargetInfo: JSON
         do {

Tests/TSCUtilityTests/TripleTests.swift

@@ -40,6 +40,9 @@ class TripleTests : XCTestCase {
         let linuxWithABIVersion = try? Triple("x86_64-unknown-linux-gnu42")
         XCTAssertEqual(linuxWithABIVersion!.abi, .other(name: "gnu"))
         XCTAssertEqual(linuxWithABIVersion!.abiVersion, "42")
+
+        let androidArm = try? Triple("armv7a-unknown-linux-androideabi")
+        XCTAssertEqual(androidArm!.arch, .armv7)
     }
 
     func testEquality() throws {