Do not add redundant -pie when building static executables on Linux platforms

It otherwise results in a warning from the Clang linker driver.

Resolves rdar://143793051

Author: artemcm

Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift

@@ -86,6 +86,12 @@ extension GenericUnixToolchain {
         }
       }
 
+      let staticStdlib = parsedOptions.hasFlag(positive: .staticStdlib,
+                                               negative: .noStaticStdlib,
+                                                   default: false)
+      let staticExecutable = parsedOptions.hasFlag(positive: .staticExecutable,
+                                                   negative: .noStaticExecutable,
+                                                  default: false)
       let clangTool: Tool = cxxCompatEnabled ? .clangxx : .clang
       var clangPath = try getToolPath(clangTool)
       if let toolsDirPath = parsedOptions.getLastArgument(.toolsDirectory) {
@@ -105,7 +111,7 @@ extension GenericUnixToolchain {
       }
 
       // Executables on Linux get -pie
-      if targetTriple.os == .linux && linkerOutputType == .executable {
+      if targetTriple.os == .linux && linkerOutputType == .executable && !staticExecutable {
         commandLine.appendFlag("-pie")
       }
 
@@ -132,12 +138,6 @@ extension GenericUnixToolchain {
         }
       }
 
-      let staticStdlib = parsedOptions.hasFlag(positive: .staticStdlib,
-                                               negative: .noStaticStdlib,
-                                                   default: false)
-      let staticExecutable = parsedOptions.hasFlag(positive: .staticExecutable,
-                                                   negative: .noStaticExecutable,
-                                                  default: false)
       let isEmbeddedEnabled = parsedOptions.isEmbeddedEnabled
 
       let toolchainStdlibRpath = parsedOptions

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -2056,6 +2056,45 @@ final class SwiftDriverTests: XCTestCase {
       ]))
     }
 
+    do {
+      try withTemporaryDirectory { path in
+        try localFileSystem.writeFileContents(path.appending(components: "linux", "static-executable-args.lnk")) {
+          $0.send("empty")
+        }
+        // Ensure that when building a static executable on Linux we do not pass in
+        // a redundant '-pie'
+        var driver = try Driver(args: commonArgs + ["-emit-executable", "-L", "/tmp", "-Xlinker", "--export-all",
+                                                    "-Xlinker", "-E", "-Xclang-linker", "foo",
+                                                    "-resource-dir", path.pathString,
+                                                    "-static-executable",
+                                                    "-target", "x86_64-unknown-linux"], env: env)
+        let plannedJobs = try driver.planBuild()
+        XCTAssertEqual(plannedJobs.count, 4)
+        let linkJob = plannedJobs[3]
+        let cmd = linkJob.commandLine
+        XCTAssertFalse(cmd.contains(.flag("-pie")))
+      }
+
+    }
+
+    do {
+      try withTemporaryDirectory { path in
+        try localFileSystem.writeFileContents(path.appending(components: "linux", "static-executable-args.lnk")) {
+          $0.send("empty")
+        }
+        // Ensure that when building a non-static executable on Linux, we specify '-pie'
+        var driver = try Driver(args: commonArgs + ["-emit-executable", "-L", "/tmp", "-Xlinker", "--export-all",
+                                                    "-Xlinker", "-E", "-Xclang-linker", "foo",
+                                                    "-resource-dir", path.pathString,
+                                                    "-target", "x86_64-unknown-linux"], env: env)
+        let plannedJobs = try driver.planBuild()
+        XCTAssertEqual(plannedJobs.count, 4)
+        let linkJob = plannedJobs[3]
+        let cmd = linkJob.commandLine
+        XCTAssertTrue(cmd.contains(.flag("-pie")))
+      }
+    }
+
     do {
       // Xlinker flags
       // Ensure that Xlinker flags are passed as such to the clang linker invocation.