tjh.dev
1--- a/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
2+++ b/Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
3@@ -10,6 +10,7 @@
4 //
5 //===----------------------------------------------------------------------===//
6
7+import Foundation
8 import SwiftOptions
9
10 import func TSCBasic.lookupExecutablePath
11@@ -120,7 +121,20 @@ extension GenericUnixToolchain {
12 // just using `clang` and avoid a dependency on the C++ runtime.
13 let clangTool: Tool =
14 parsedOptions.hasArgument(.enableExperimentalCxxInterop) ? .clangxx : .clang
15- var clangPath = try getToolPath(clangTool)
16+
17+ // For Nix, prefer linking using the wrapped system clang, instead of using
18+ // the unwrapped clang packaged with swift. The latter is unable to link, but
19+ // we still want to use it for other purposes (clang importer).
20+ var clangPath: AbsolutePath
21+ let env = ProcessInfo.processInfo.environment
22+ if let nixCC = env["NIX_CC"],
23+ let binPath = try? AbsolutePath(validating: "\(nixCC)/bin"),
24+ let tool = lookupExecutablePath(filename: parsedOptions.hasArgument(.enableExperimentalCxxInterop)
25+ ? "clang++" : "clang",
26+ searchPaths: [binPath]) {
27+ clangPath = tool
28+ } else {
29+ clangPath = try getToolPath(clangTool)
30 if let toolsDirPath = parsedOptions.getLastArgument(.toolsDirectory) {
31 // FIXME: What if this isn't an absolute path?
32 let toolsDir = try AbsolutePath(validating: toolsDirPath.asSingle)
33@@ -136,6 +150,7 @@ extension GenericUnixToolchain {
34 commandLine.appendFlag("-B")
35 commandLine.appendPath(toolsDir)
36 }
37+ } // nixCC
38
39 // Executables on Linux get -pie
40 if targetTriple.os == .linux && linkerOutputType == .executable {