From 2efa7d6bff5f033a6fcbb20f41896d9f08ff59dd Mon Sep 17 00:00:00 2001
From: Alastair Houghton <ahoughton@apple.com>
Date: Thu, 22 Feb 2024 14:28:44 +0000
Subject: [PATCH 1/2] Update driver for fully static Linux.

The Swift driver needs to understand the new triple and needs to
know the platform name to which that corresponds.

rdar://123442522
---
 .../GenericUnixToolchain+LinkerSupport.swift  |  3 ++-
 .../Utilities/Triple+Platforms.swift          | 14 ++++++++++-
 Sources/SwiftDriver/Utilities/Triple.swift    | 25 +++++++++++++------
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift b/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
index 7238ca7c9..20e2fdfd1 100644
--- a/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
+++ b/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
@@ -18,7 +18,8 @@ import struct TSCBasic.AbsolutePath
 extension GenericUnixToolchain {
   private func defaultLinker(for targetTriple: Triple) -> String? {
     if targetTriple.os == .openbsd || targetTriple.os == .freeBSD ||
-        targetTriple.environment == .android {
+         targetTriple.environment == .android ||
+         targetTriple.isFullyStaticLinux {
       return "lld"
     }
 
diff --git a/Sources/SwiftDriver/Utilities/Triple+Platforms.swift b/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
index 380560093..1c8e38c47 100644
--- a/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
+++ b/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
@@ -292,7 +292,19 @@ extension Triple {
       return conflatingDarwin ? "darwin" : darwinPlatform.platformName
 
     case .linux:
-      return environment == .android ? "android" : "linux"
+      switch environment {
+      case .musl:
+        if vendor == .swift {
+          return "linux-static"
+        }
+        fallthrough
+      case .musl, .musleabihf, .musleabi:
+        return "musl"
+      case .android:
+        return "android"
+      default:
+        return "linux"
+      }
     case .freeBSD:
       return "freebsd"
     case .openbsd:
diff --git a/Sources/SwiftDriver/Utilities/Triple.swift b/Sources/SwiftDriver/Utilities/Triple.swift
index e3cc71dbb..100ddb942 100644
--- a/Sources/SwiftDriver/Utilities/Triple.swift
+++ b/Sources/SwiftDriver/Utilities/Triple.swift
@@ -1028,6 +1028,7 @@ extension Triple {
     case mesa
     case suse
     case openEmbedded = "oe"
+    case swift
 
     fileprivate static func parse(_ component: Substring) -> Triple.Vendor? {
       switch component {
@@ -1063,6 +1064,8 @@ extension Triple {
         return .suse
       case "oe":
         return .openEmbedded
+      case "swift":
+        return .swift
       default:
         return nil
       }
@@ -1706,13 +1709,21 @@ fileprivate extension Array {
   }
 }
 
-// MARK: - Linker support
+// MARK: - Fully static Linux support
 
 extension Triple {
-    /// Returns `true` if a given triple supports producing fully statically linked executables by providing `-static`
-    /// flag to the linker. This implies statically linking platform's libc, and of those that Swift supports currently
-    /// only Musl allows that reliably.
-    var supportsStaticExecutables: Bool {
-        self.environment == .musl
-    }
+  /// Returns `true` if this is the triple for Swift's fully statically
+  /// linked Linux target.
+  var isFullyStaticLinux: Bool {
+    self.vendor == .swift && self.environment == .musl
+  }
+
+  /// Returns `true` if a given triple supports producing fully
+  /// statically linked executables by providing `-static` flag to
+  /// the linker. This implies statically linking platform's libc,
+  /// and of those that Swift supports currently only Musl allows
+  /// that reliably.
+  var supportsStaticExecutables: Bool {
+    self.isFullyStaticLinux
+  }
 }

From 7b22cc60abf282e4cf1d024ba715bba20593e5c6 Mon Sep 17 00:00:00 2001
From: Alastair Houghton <ahoughton@apple.com>
Date: Tue, 27 Feb 2024 14:59:49 +0000
Subject: [PATCH 2/2] Add a comment about linux-static.

"linux-static" refers to the new fully-statically-linked Linux support;
the point here is that we want to distinguish that from just "Linux
with musl", which is an entirely reasonable thing for us to support
separately.

rdar://123442522
---
 Sources/SwiftDriver/Utilities/Triple+Platforms.swift | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Sources/SwiftDriver/Utilities/Triple+Platforms.swift b/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
index 1c8e38c47..4814ffe81 100644
--- a/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
+++ b/Sources/SwiftDriver/Utilities/Triple+Platforms.swift
@@ -294,6 +294,8 @@ extension Triple {
     case .linux:
       switch environment {
       case .musl:
+        // The triple for linux-static is <arch>-swift-linux-musl, to distinguish
+        // it from a "normal" musl set-up (ala Alpine).
         if vendor == .swift {
           return "linux-static"
         }