Merge pull request swiftlang#576 from swiftlang/owenv/dead-strip

Fixup cross platform specs handling of DEAD_CODE_STRIPPING

Author: owenv

Sources/SWBGenericUnixPlatform/Specs/UnixLd.xcspec

@@ -102,6 +102,16 @@
                 };
                 Condition = "$(ALTERNATE_LINKER) == gold";
             },
+            {
+                Name = "DEAD_CODE_STRIPPING";
+                Type = Boolean;
+                DefaultValue = NO;
+                Condition = "$(MACH_O_TYPE) != mh_object";
+                CommandLineArgs = {
+                    YES = ("-Xlinker", "--gc-sections");
+                    NO = ();
+                };
+            },
             {
                 // Frameworks are Mac specific
                 Name = "SYSTEM_FRAMEWORK_SEARCH_PATHS";

Sources/SWBQNXPlatform/Specs/QNXLd.xcspec

@@ -96,6 +96,11 @@
                 };
                 Condition = "$(ALTERNATE_LINKER) == gold";
             },
+            {
+                Name = "DEAD_CODE_STRIPPING";
+                Type = Boolean;
+                Condition = "NO";
+            },
             {
                 // Frameworks are Mac specific
                 Name = "SYSTEM_FRAMEWORK_SEARCH_PATHS";

Sources/SWBUniversalPlatform/Specs/Ld.xcspec

@@ -459,7 +459,10 @@
                 Type = Boolean;
                 DefaultValue = NO;
                 Condition = "$(MACH_O_TYPE) != mh_object";
-                CommandLineFlag = "-dead_strip";
+                CommandLineArgs = {
+                    YES = ("-dead_strip");
+                    NO = ();
+                };
             },
             {
                 Name = "BUNDLE_LOADER";

Sources/SWBWebAssemblyPlatform/Specs/WasmLd.xcspec

@@ -64,6 +64,16 @@
                     NO = ();
                 };
             },
+            {
+                Name = "DEAD_CODE_STRIPPING";
+                Type = Boolean;
+                DefaultValue = NO;
+                Condition = "$(MACH_O_TYPE) != mh_object";
+                CommandLineArgs = {
+                    YES = ("-Xlinker", "--gc-sections");
+                    NO = ();
+                };
+            },
             {
                 // Frameworks are Mac specific
                 Name = "SYSTEM_FRAMEWORK_SEARCH_PATHS";

Sources/SWBWindowsPlatform/Specs/WindowsLd.xcspec

@@ -102,6 +102,16 @@
                 Type = String;
                 Condition = "NO";
             },
+            {
+                Name = "DEAD_CODE_STRIPPING";
+                Type = Boolean;
+                DefaultValue = NO;
+                Condition = "$(MACH_O_TYPE) != mh_object";
+                CommandLineArgs = {
+                    YES = ("-Xlinker", "/OPT:REF");
+                    NO = ();
+                };
+            },
             {
                 // No such concept
                 Name = "LD_RUNPATH_SEARCH_PATHS";

Tests/SWBTaskConstructionTests/TaskConstructionTests.swift

@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import struct Foundation.Data
+import Foundation
 
 import Testing
 
@@ -8657,6 +8657,64 @@ fileprivate struct TaskConstructionTests: CoreBasedTests {
         }
     }
 
+    @Test(.requireSDKs(.host))
+    func crossPlatformDeadCodeStripping() async throws {
+        try await withTemporaryDirectory { tmpDir in
+            let testProject = TestProject(
+                "aProject",
+                sourceRoot: tmpDir,
+                groupTree: TestGroup(
+                    "SomeFiles", path: "Sources",
+                    children: [
+                        TestFile("SourceFile.c"),
+                    ]),
+                buildConfigurations: [
+                    TestBuildConfiguration("Debug", buildSettings: [
+                        "DEAD_CODE_STRIPPING": "YES",
+                        "ONLY_ACTIVE_ARCH": "YES"
+                    ])
+                ],
+                targets: [
+                    TestStandardTarget(
+                        "Library",
+                        type: .dynamicLibrary,
+                        buildConfigurations: [
+                            TestBuildConfiguration("Debug")
+                        ],
+                        buildPhases: [
+                            TestSourcesBuildPhase([
+                                "SourceFile.c",
+                            ])
+                        ]
+                    )]
+            )
+
+            let fs = PseudoFS()
+
+            let core = try await getCore()
+            let tester = try TaskConstructionTester(core, testProject)
+
+            try await tester.checkBuild(BuildParameters(configuration: "Debug", overrides: [:]), runDestination: .host, fs: fs) { results in
+                try results.checkTask(.matchRuleType("Ld")) { task in
+                    switch try ProcessInfo.processInfo.hostOperatingSystem() {
+                    case .macOS:
+                        task.checkCommandLineContains(["-dead_strip"])
+                        task.checkCommandLineDoesNotContain("--gc-sections")
+                        task.checkCommandLineDoesNotContain("/OPT:REF")
+                    case .windows:
+                        task.checkCommandLineDoesNotContain("-dead_strip")
+                        task.checkCommandLineDoesNotContain("--gc-sections")
+                        task.checkCommandLineContains(["/OPT:REF"])
+                    default:
+                        task.checkCommandLineDoesNotContain("-dead_strip")
+                        task.checkCommandLineContains(["--gc-sections"])
+                        task.checkCommandLineDoesNotContain("/OPT:REF")
+                    }
+                }
+            }
+        }
+    }
+
     @Test(.requireSDKs(.macOS))
     func warningSuppression() async throws {
         try await withTemporaryDirectory { tmpDir in