Add Swift stdlib to dyld library search path for swift-run and swift-test

<rdar://problem/46390701>

Author: aciidgh

Sources/Commands/SwiftRunTool.swift

@@ -16,6 +16,7 @@ import PackageModel
 
 import func POSIX.chdir
 import func POSIX.getcwd
+import func POSIX.setenv
 
 /// An enumeration of the errors that can be generated by the run tool.
 private enum RunError: Swift.Error {
@@ -194,6 +195,15 @@ public class SwiftRunTool: SwiftTool<RunToolOptions> {
         }
 
         let pathRelativeToWorkingDirectory = excutablePath.relative(to: originalWorkingDirectory)
+
+      #if os(macOS)
+        // Insert path to Swift stdlib in library search path.
+        // It is fine to just taint our env like this because we don't expect to
+        // return from the following exec call.
+        let dyldLibPath = try getToolchain().makeDyldLibPath(withExistingValue: Process.env["DYLD_LIBRARY_PATH"])
+        try setenv("DYLD_LIBRARY_PATH", value: dyldLibPath)
+      #endif
+
         try exec(path: excutablePath.asString, args: [pathRelativeToWorkingDirectory.asString] + arguments)
     }
 

Sources/Commands/SwiftTestTool.swift

@@ -955,6 +955,11 @@ fileprivate func constructTestEnvironment(
         env["LLVM_PROFILE_FILE"] = codecovProfile.asString
     }
 
+  #if os(macOS)
+    // Add path to Swift stdlib.
+    env["DYLD_LIBRARY_PATH"] = toolchain.makeDyldLibPath(withExistingValue: env["DYLD_LIBRARY_PATH"])
+  #endif
+
   #if !os(macOS)
     return env
   #else

Sources/Workspace/UserToolchain.swift

@@ -65,6 +65,20 @@ public final class UserToolchain: Toolchain {
         return swiftCompiler.parentDirectory.appending(component: "swift")
     }
 
+    /// Path containing the macOS Swift stdlib.
+    var macosSwiftStdlib: AbsolutePath {
+        return resolveSymlinks(swiftCompiler).appending(RelativePath("../../lib/swift/macosx"))
+    }
+
+    public func makeDyldLibPath(withExistingValue value: String? = nil) -> String {
+        var dyldLibPath = ""
+        if let dyldLib = value, !dyldLib.isEmpty {
+            dyldLibPath = dyldLib + ":"
+        }
+        dyldLibPath += macosSwiftStdlib.asString
+        return dyldLibPath
+    }
+
     /// Path to the xctest utility.
     ///
     /// This is only present on macOS.

Utilities/bootstrap

@@ -747,13 +747,13 @@ def get_swiftc_path():
     except:
         error("unable to find 'swiftc' tool for bootstrap build")
 
-def delete_rpath(rpath, binary):
+def delete_rpath(rpath, binary, allowFailing=False):
     if platform.system() == 'Darwin':
         cmd = ["install_name_tool", "-delete_rpath", rpath, binary]
         note("removing RPATH from %s: %s" % (
                 binary, ' '.join(cmd)))
         result = subprocess.call(cmd)
-        if result != 0:
+        if not allowFailing and result != 0:
             error("command failed with exit status %d" % (result,))
     else:
         error("unable to remove RPATHs on this platform")
@@ -789,10 +789,8 @@ def installBinary(binary_path, install_path, swiftc_path, add_rpaths=[], delete_
     if platform.system() == 'Darwin':
         installed_path = os.path.join(
             install_path, os.path.basename(binary_path))
-        stdlib_path = os.path.normpath(
-            os.path.join(os.path.dirname(os.path.realpath(swiftc_path)), "..",
-                         "lib", "swift", "macosx"))
-        delete_rpath(stdlib_path, installed_path)
+        stdlib_path = swift_macos_stdlib_path(swiftc_path)
+        delete_rpath(stdlib_path, installed_path, True)
 
         # Remove additional RPATHs, if requested.
         for rpath in delete_rpaths:
@@ -802,6 +800,8 @@ def installBinary(binary_path, install_path, swiftc_path, add_rpaths=[], delete_
         for rpath in add_rpaths:
             add_rpath(rpath, installed_path)
 
+def swift_macos_stdlib_path(swiftc):
+    return os.path.normpath(os.path.join(os.path.dirname(os.path.realpath(swiftc)), "..", "lib", "swift", "macosx"))
 
 def llbuild_import_paths(args):
     if args.llbuild_link_framework:
@@ -1232,6 +1232,13 @@ def main():
     ]
     if args.sysroot:
         env_cmd.append("SYSROOT=" + args.sysroot)
+
+    # Look for stdlib libraries using dyld library path on macOS.
+    if platform.system() == 'Darwin':
+        stdlib_path = swift_macos_stdlib_path(args.swiftc_path)
+        build_flags.extend(["-Xlinker", "-rpath", "-Xlinker", stdlib_path])
+        env_cmd.append("DYLD_LIBRARY_PATH=" + stdlib_path)
+
     cmd = env_cmd + [bootstrapped_product] + build_flags
 
     # Always build tests in stage2.