Cherry-pick: Revert change to avoid dead code striping with debug dylib (rdar://154656898) (#646)

jonathanpenn · web-flow · commit 163cc7ef639b · 2025-07-08T09:27:17.000-07:00
We don't need this right now. Turned out to be more restrictive than necessary.

Cherry-picked from release/6.2
diff --git a/Sources/SWBCore/SpecImplementations/Tools/LinkerTools.swift b/Sources/SWBCore/SpecImplementations/Tools/LinkerTools.swift
@@ -524,10 +524,6 @@ public final class LdLinkerSpec : GenericLinkerSpec, SpecIdentifierType, @unchec
                     return nil
                 }
                 return cbc.scope.namespace.parseLiteralString(name)
-            case BuiltinMacros.DEAD_CODE_STRIPPING where isPreviewDylib:
-                // We need to keep otherwise unused stub executor library symbols present so
-                // PreviewsInjection can call them when doing the XOJIT handshake.
-                return cbc.scope.namespace.parseLiteralString("NO")
             case BuiltinMacros.LD_EXPORT_SYMBOLS where isPreviewDylib,
                 BuiltinMacros.LD_EXPORT_GLOBAL_SYMBOLS where isPreviewDylib:
                 // We need to keep otherwise unused stub executor library symbols present so
diff --git a/Tests/SWBBuildSystemTests/PreviewsBuildOperationTests.swift b/Tests/SWBBuildSystemTests/PreviewsBuildOperationTests.swift
@@ -308,7 +308,7 @@ fileprivate struct PreviewsBuildOperationTests: CoreBasedTests {
                                 linkerCommandLine.remove(at: idx)
                             }
                         }
-                        XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-Xlinker", "-warn_unused_dylibs", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
+                        XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-Xlinker", "-warn_unused_dylibs", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-dead_strip", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
                     }
                 }
 
@@ -615,7 +615,7 @@ fileprivate struct PreviewsBuildOperationTests: CoreBasedTests {
                                 linkerCommandLine.remove(at: idx)
                             }
                         }
-                        XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-fobjc-link-runtime", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
+                        XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-dead_strip", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-fobjc-link-runtime", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
                     }
                 }
             }
diff --git a/Tests/SwiftBuildTests/GeneratePreviewInfoTests.swift b/Tests/SwiftBuildTests/GeneratePreviewInfoTests.swift
@@ -228,6 +228,7 @@ fileprivate struct GeneratePreviewInfoTests: CoreBasedTests {
                                 "\(tmpDir.str)/Test/build/Test.build/Debug-iphoneos/App.build/Objects-normal/\(activeRunDestination.targetArchitecture)/App.LinkFileList",
                                 "-install_name",
                                 "@rpath/App.debug.dylib",
+                                "-dead_strip",
                                 "-Xlinker",
                                 "-object_path_lto",
                                 "-Xlinker",

Original file line number	Diff line number	Diff line change
`@@ -308,7 +308,7 @@ fileprivate struct PreviewsBuildOperationTests: CoreBasedTests {`
`308`	`308`	`linkerCommandLine.remove(at: idx)`
`309`	`309`	`}`
`310`	`310`	`}`
`311`		- XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-Xlinker", "-warn_unused_dylibs", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
	`311`	+ XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-Xlinker", "-warn_unused_dylibs", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-dead_strip", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
`312`	`312`	`}`
`313`	`313`	`}`
`314`	`314`
`@@ -615,7 +615,7 @@ fileprivate struct PreviewsBuildOperationTests: CoreBasedTests {`
`615`	`615`	`linkerCommandLine.remove(at: idx)`
`616`	`616`	`}`
`617`	`617`	`}`
`618`		- XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-fobjc-link-runtime", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
	`618`	+ XCTAssertEqualSequences(linkerCommandLine, ["\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang", "-Xlinker", "-reproducible", "-target", "\(results.runDestinationTargetArchitecture)-apple-ios\(core.loadSDK(.iOSSimulator).defaultDeploymentTarget)-simulator", "-dynamiclib", "-isysroot", core.loadSDK(.iOSSimulator).path.str, "-Os", "-L\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-L\(srcRoot.str)/build/Debug-iphonesimulator", "-F\(srcRoot.str)/build/EagerLinkingTBDs/Debug-iphonesimulator", "-F\(srcRoot.str)/build/Debug-iphonesimulator", "-filelist", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.LinkFileList", "-install_name", "@rpath/AppTarget.debug.dylib", "-dead_strip", "-Xlinker", "-object_path_lto", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_lto.o", "-rdynamic", "-Xlinker", "-objc_abi_version", "-Xlinker", "2", "-Xlinker", "-dependency_info", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget_dependency_info.dat", "-fobjc-link-runtime", "-L\(core.developerPath.path.str)/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator", "-L/usr/lib/swift", "-Xlinker", "-add_ast_path", "-Xlinker", "\(srcRoot.str)/build/ProjectName.build/Debug-iphonesimulator/AppTarget.build/Objects-normal/\(results.runDestinationTargetArchitecture)/AppTarget.swiftmodule", "-Xlinker", "-alias", "-Xlinker", "_main", "-Xlinker", "___debug_main_executable_dylib_entry_point", "-Xlinker", "-no_adhoc_codesign", "-o", "\(srcRoot.str)/build/Debug-iphonesimulator/AppTarget.app/AppTarget.debug.dylib"])
`619`	`619`	`}`
`620`	`620`	`}`
`621`	`621`	`}`