Remove support for compiling with bitcode.

This removes support for compiling files with bitcode from SWBuild, as this functionality is no longer supported. This removes a lot of functionally dead code.

Support for stripping bitcode from copied files remains, as there are extant libraries and XCFrameworks which contain bitcode, which must be stripped. Bitcode was only supported for a subset of platforms, to the assignment of STRIP_BITCODE_FROM_COPIED_FILES in Settings based on platform remains, so time isn't spent stripping nonexistent bitcode from other platforms.

Some interfaces which Xcode uses continue to refer to bitcode for compatibility, but effectively do nothing.

Note that the references to bitcode in the OpenCL support are a concept internal to that tool, and independent of the support being removed here.

rdar://148287993

Author: mhrawdon

Sources/SWBApplePlatform/Specs/Darwin Package Types.xcspec

@@ -58,7 +58,6 @@
         Description = "OCUnit Test Bundle";
         DefaultBuildSettings = {
             WRAPPER_SUFFIX = "octest";
-            ENABLE_BITCODE = NO;
         };
         ProductReference = {
             FileType = wrapper.cfbundle;

Sources/SWBApplePlatform/Specs/Darwin Product Types.xcspec

@@ -155,7 +155,6 @@
         Description = "OCUnit Test Bundle";
         DefaultBuildProperties = {
             WRAPPER_EXTENSION = "octest";
-            ENABLE_BITCODE = NO;
             ENTITLEMENTS_REQUIRED = NO;
         };
         PackageTypes = (

Sources/SWBApplePlatform/Specs/Embedded-Shared.xcspec

@@ -28,11 +28,6 @@
         Identifier = com.apple.build-system.native;
         BasedOn = "default:com.apple.build-system.native";
         Properties = (
-            {
-                Name = "ENABLE_BITCODE";
-                Type = Boolean;
-                DefaultValue = NO;
-            },
         );
     },
 )

Sources/SWBApplePlatform/Specs/watchOS Shared.xcspec

@@ -117,50 +117,6 @@
         BasedOn = "com.apple.product-type.app-extension";
     },
 
-    // --- LLVM Compiler
-    {
-        _Domain = watchos-shared;
-        Type = Compiler;
-        Identifier = "com.apple.compilers.llvm.clang.1_0.compiler";
-        BasedOn = "default:com.apple.compilers.llvm.clang.1_0.compiler";
-        InputFileTypes = (
-            "sourcecode.c.c",
-            "sourcecode.c.objc",
-            "sourcecode.cpp.cpp",
-            "sourcecode.cpp.objcpp",
-            {
-                "FileType" = "sourcecode.asm";
-                "Condition" = "! $(ENABLE_BITCODE)";
-                "ErrorMessage" = "$(InputFileName): Assembly files are not supported for the $(PLATFORM_DISPLAY_NAME) platform (arch $(CURRENT_ARCH)).";
-            },
-        );
-        Options = (
-            // Generate bitcode options - not visible in the build settings.
-            {
-                Name = "CLANG_BITCODE_GENERATION_MODE";
-                Type = Enumeration;
-                Values = (
-                    none,
-                    marker,
-                    bitcode,
-                );
-                DefaultValue = "$(BITCODE_GENERATION_MODE)";
-                Condition = "$(ENABLE_BITCODE)";
-                CommandLineArgs = {
-                    none = ();
-                    marker = (
-                        "-fembed-bitcode-marker",
-                        "-fno-gnu-inline-asm",
-                    );
-                    bitcode = (
-                        "-fembed-bitcode",
-                        "-fno-gnu-inline-asm",
-                    );
-                };
-            },
-        );
-    },
-
     // Actool ATV specific bits
     {
         _Domain = watchos-shared;

Sources/SWBCore/Settings/BuiltinMacros.swift

@@ -224,11 +224,9 @@ public final class BuiltinMacros {
 
     public static let ACTION = BuiltinMacros.declareStringMacro("ACTION")
     public static let ARCHS = BuiltinMacros.declareStringListMacro("ARCHS")
-    public static let BITCODE_GENERATION_MODE = BuiltinMacros.declareStringMacro("BITCODE_GENERATION_MODE")
     public static let BUILD_COMPONENTS = BuiltinMacros.declareStringListMacro("BUILD_COMPONENTS")
     public static let DEPLOYMENT_LOCATION = BuiltinMacros.declareBooleanMacro("DEPLOYMENT_LOCATION")
     public static let DEPLOYMENT_POSTPROCESSING = BuiltinMacros.declareBooleanMacro("DEPLOYMENT_POSTPROCESSING")
-    public static let ENABLE_BITCODE = BuiltinMacros.declareBooleanMacro("ENABLE_BITCODE")
     public static let ENABLE_TESTABILITY = BuiltinMacros.declareBooleanMacro("ENABLE_TESTABILITY")
     public static let ENABLE_TESTING_SEARCH_PATHS = BuiltinMacros.declareBooleanMacro("ENABLE_TESTING_SEARCH_PATHS")
     public static let ENABLE_PRIVATE_TESTING_SEARCH_PATHS = BuiltinMacros.declareBooleanMacro("ENABLE_PRIVATE_TESTING_SEARCH_PATHS")
@@ -802,7 +800,6 @@ public final class BuiltinMacros {
     public static let __KNOWN_SPI_INSTALL_PATHS = BuiltinMacros.declareStringListMacro("__KNOWN_SPI_INSTALL_PATHS")
     public static let LD = BuiltinMacros.declareStringMacro("LD")
     public static let LDPLUSPLUS = BuiltinMacros.declareStringMacro("LDPLUSPLUS")
-    public static let LD_BITCODE_GENERATION_MODE = BuiltinMacros.declareStringMacro("LD_BITCODE_GENERATION_MODE")
     public static let LD_CLIENT_NAME = BuiltinMacros.declareStringMacro("LD_CLIENT_NAME")
     public static let LD_DEPENDENCY_INFO_FILE = BuiltinMacros.declarePathMacro("LD_DEPENDENCY_INFO_FILE")
     public static let LD_DYLIB_INSTALL_NAME = BuiltinMacros.declareStringMacro("LD_DYLIB_INSTALL_NAME")
@@ -1426,7 +1423,6 @@ public final class BuiltinMacros {
         AdditionalCommandLineArguments,
         AppIdentifierPrefix,
         BLOCKLISTS_PATH,
-        BITCODE_GENERATION_MODE,
         BUILD_COMPONENTS,
         BUILD_DESCRIPTION_CACHE_DIR,
         BUILD_DIR,
@@ -1667,7 +1663,6 @@ public final class BuiltinMacros {
         ENABLE_DEFAULT_SEARCH_PATHS_IN_LIBRARY_SEARCH_PATHS,
         ENABLE_DEFAULT_SEARCH_PATHS_IN_REZ_SEARCH_PATHS,
         ENABLE_DEFAULT_SEARCH_PATHS_IN_SWIFT_INCLUDE_PATHS,
-        ENABLE_BITCODE,
         ENABLE_CLOUD_SIGNING,
         ENABLE_GENERIC_TASK_CACHING,
         GENERIC_TASK_CACHE_ENABLE_DIAGNOSTIC_REMARKS,
@@ -1863,7 +1858,6 @@ public final class BuiltinMacros {
         LAUNCH_CONSTRAINT_SELF,
         LD,
         LDPLUSPLUS,
-        LD_BITCODE_GENERATION_MODE,
         LD_CLIENT_NAME,
         LD_DEPENDENCY_INFO_FILE,
         LD_DYLIB_INSTALL_NAME,

Sources/SWBCore/Settings/Settings.swift

@@ -2617,7 +2617,7 @@ private class SettingsBuilder {
     // FIXME: Why is this logic not part of loading the SDK in SDKRegistry.registerSDK()?  I think all of the information currently used by this method should be available there.
     func addPlatformSDKSettings(_ platform: Platform?, _ sdk: SDK, _ sdkVariant: SDKVariant?) {
         pushTable(.exported) { table in
-            // bitcode
+            // Bitcode is no longer supported, so we want to continue to strip bitcode from non-simulator embedded platforms as we always have.
             if let platform, !platform.isSimulator, platform.correspondingSimulatorPlatformName != nil {
                 table.push(BuiltinMacros.STRIP_BITCODE_FROM_COPIED_FILES, literal: true)
             }
@@ -4093,12 +4093,6 @@ private class SettingsBuilder {
         // Determine a preferred architecture for indexing, single-file actions, and the static analyzer.
         self.preferredArch = getPreferredArch(effectiveArchs)
 
-        // For installation and deployment, we need to generate proper bitcode: -fembed-bitcode/-embed-bitcode.
-        // NOTE! Do not simply check DEPLOYMENT_POSTPROCESSING as it may not be in-scope yet.
-        if parameters.action.isInstallAction || scope.evaluate(BuiltinMacros.DEPLOYMENT_POSTPROCESSING) {
-            table.push(BuiltinMacros.BITCODE_GENERATION_MODE, literal: "bitcode")
-        }
-
         // Set `ARCHS` to the list of architectures we ended up with, and save the original value.
         table.push(BuiltinMacros.__ARCHS__, literal: originalArchs)
         table.push(BuiltinMacros.ARCHS, literal: effectiveArchs.removingDuplicates())
@@ -4117,10 +4111,6 @@ private class SettingsBuilder {
         table.push(BuiltinMacros.__SWIFT_MODULE_ONLY_ARCHS__, literal: originalModuleOnlyArchs)
         table.push(BuiltinMacros.SWIFT_MODULE_ONLY_ARCHS, literal: moduleOnlyArchs)
 
-        if (scope.evaluate(BuiltinMacros.ENABLE_TESTING_SEARCH_PATHS) && project?.isPackage != true) || !["iphoneos", "appletvos", "watchos"].contains(specLookupContext.platform?.name) {
-            table.push(BuiltinMacros.ENABLE_BITCODE, literal: false)
-        }
-
         // FIXME: There is a more random, but questionable stuff here. To be added in a test case driven fashion.
 
         // Resolve some of the key path settings to be absolute.
@@ -4200,21 +4190,6 @@ private class SettingsBuilder {
             }))
         }
 
-        // Bitcode support was deprecated in Xcode 14 and is being turned off by default in Xcode 15, but there is a user default which can enable it.
-        if scope.evaluate(BuiltinMacros.ENABLE_BITCODE) {
-            if UserDefaults.enableBitcodeSupport {
-                // If we're going to generate bitcode, then symbol editing must be done by the linker, not by a separate nmedit invocation.
-                table.push(BuiltinMacros.SEPARATE_SYMBOL_EDIT, literal: false)
-
-                self.targetDiagnostics.append(Diagnostic(behavior: .warning, location: .buildSetting(BuiltinMacros.ENABLE_BITCODE), data: DiagnosticData("Building with bitcode is deprecated. Please update your project and/or target settings to disable bitcode.")))
-            }
-            else {
-                table.push(BuiltinMacros.ENABLE_BITCODE, literal: false)
-
-                self.targetDiagnostics.append(Diagnostic(behavior: .warning, location: .buildSetting(BuiltinMacros.ENABLE_BITCODE), data: DiagnosticData("Ignoring ENABLE_BITCODE because building with bitcode is no longer supported.")))
-            }
-        }
-
         // If testability is enabled, then that overrides certain other settings, and in a way that the user cannot override: They're either using testability, or they're not.
         if scope.evaluate(BuiltinMacros.ENABLE_TESTABILITY) {
             table.push(BuiltinMacros.GCC_SYMBOLS_PRIVATE_EXTERN, literal: false)

Sources/SWBCore/SpecImplementations/Tools/CopyTool.swift

@@ -42,8 +42,6 @@ public final class CopyToolSpec : CompilerSpec, SpecIdentifierType, @unchecked S
         let outputPath = cbc.output
 
         // Lookup function for computing the command line.
-        let enableBitcode = cbc.scope.evaluate(BuiltinMacros.ENABLE_BITCODE)
-        let bitcodeGenerationMode = cbc.scope.evaluate(BuiltinMacros.BITCODE_GENERATION_MODE)
         func lookup(_ macro: MacroDeclaration) -> MacroExpression? {
             switch macro {
             case BuiltinMacros.COPY_PHASE_STRIP, BuiltinMacros.PBXCP_STRIP_UNSIGNED_BINARIES:
@@ -63,41 +61,22 @@ public final class CopyToolSpec : CompilerSpec, SpecIdentifierType, @unchecked S
                 guard stripBitcode else {
                     return nil
                 }
-                // If we have been directed to strip bitcode, and bitcode is either disabled or is turned to a level less than 'bitcode' (i.e., less than full bitcode), then we should strip bitcode from binaries we copy.
-                if !enableBitcode || bitcodeGenerationMode != "bitcode" {
-                    return Static { cbc.scope.namespace.parseLiteralString("YES") } as MacroStringExpression
-                }
-                return nil
+                // Always strip all bitcode.
+                return Static { cbc.scope.namespace.parseLiteralString("YES") } as MacroStringExpression
             case BuiltinMacros.PBXCP_BITCODE_STRIP_MODE:
                 guard stripBitcode else {
                     return nil
                 }
-                if !enableBitcode {
-                    // If bitcode is not enabled then strip all bitcode.
-                    return Static { cbc.scope.namespace.parseLiteralString("all") } as MacroStringExpression
-                }
-                else if bitcodeGenerationMode != "bitcode" {
-                    // If bitcode level is less than full, then strip bitcode.
-                    if bitcodeGenerationMode == "marker" {
-                        // If bitcode is enabled but to generate the marker, then strip down to a marker.
-                        return Static { cbc.scope.namespace.parseLiteralString("replace-with-marker") } as MacroStringExpression
-                    }
-                    else {
-                        // Otherwise strip all bitcode.
-                        return Static { cbc.scope.namespace.parseLiteralString("all") } as MacroStringExpression
-                    }
-                }
-                return nil
+                // Always strip all bitcode.
+                return Static { cbc.scope.namespace.parseLiteralString("all") } as MacroStringExpression
             case BuiltinMacros.PBXCP_BITCODE_STRIP_TOOL:
                 guard stripBitcode else {
                     return nil
                 }
                 // FIXME: We should change the .xcspec file to make this setting conditional on $(PBXCP_STRIP_BITCODE).  Then we can just always generate this value.
-                if !enableBitcode || bitcodeGenerationMode != "bitcode" {
-                    // Find bitcode_strip in our effective toolchains.
-                    if let bitcodeStripPath = cbc.producer.toolchains.lazy.compactMap({ $0.executableSearchPaths.lookup(Path("bitcode_strip")) }).first {
-                        return cbc.scope.namespace.parseLiteralString(bitcodeStripPath.str) as MacroStringExpression
-                    }
+                // Find bitcode_strip in our effective toolchains.
+                if let bitcodeStripPath = cbc.producer.toolchains.lazy.compactMap({ $0.executableSearchPaths.lookup(Path("bitcode_strip")) }).first {
+                    return cbc.scope.namespace.parseLiteralString(bitcodeStripPath.str) as MacroStringExpression
                 }
                 return nil
             case BuiltinMacros.PBXCP_EXCLUDE_SUBPATHS:

Sources/SWBCore/SpecImplementations/Tools/LinkerTools.swift

@@ -970,14 +970,14 @@ public final class LdLinkerSpec : GenericLinkerSpec, SpecIdentifierType, @unchec
         let argPrefix = "-Xlinker"
 
         // Args without parameters
-        for arg in ["-dynamiclib", "-bundle", "-r", "-fembed-bitcode-marker", "-dead_strip", "-nostdlib", "-rdynamic"] {
+        for arg in ["-dynamiclib", "-bundle", "-r", "-dead_strip", "-nostdlib", "-rdynamic"] {
             while let index = commandLine.firstIndex(of: arg) {
                 commandLine.remove(at: index)
             }
         }
 
         // Args without parameters (-Xlinker-prefixed, e.g. -Xlinker)
-        for arg in ["-bitcode_verify", "-export_dynamic", "-sdk_imports_each_object"] {
+        for arg in ["-export_dynamic", "-sdk_imports_each_object"] {
             while let index = commandLine.firstIndex(of: arg) {
                 guard index > 0, commandLine[index - 1] == argPrefix else { break }
                 commandLine.removeSubrange(index - 1 ... index)
@@ -996,7 +996,7 @@ public final class LdLinkerSpec : GenericLinkerSpec, SpecIdentifierType, @unchec
         }
 
         // Args with a parameter (-Xlinker-prefixed, e.g. -Xlinker arg -Xlinker param)
-        for arg in ["-object_path_lto", "-add_ast_path", "-dependency_info", "-map", "-order_file", "-bitcode_symbol_map", "-final_output", "-allowable_client", "-sdk_imports"] {
+        for arg in ["-object_path_lto", "-add_ast_path", "-dependency_info", "-map", "-order_file", "-final_output", "-allowable_client", "-sdk_imports"] {
             while let index = commandLine.firstIndex(of: arg) {
                 guard index > 0,
                     index + 2 < commandLine.count,

Sources/SWBCore/SpecImplementations/Tools/MasterObjectLink.swift

@@ -34,18 +34,6 @@ final class MasterObjectLinkSpec: CommandLineToolSpec, SpecImplementationType, @
         var commandLine = [toolSpecInfo.toolPath.str]
         commandLine += ["-r", "-arch", arch]
 
-        let supportsBitcode = await !cbc.producer.ldLinkerSpec.commandLineFromMacroDeclaration(cbc, delegate, optionContext: toolSpecInfo, BuiltinMacros.LD_BITCODE_GENERATION_MODE).isEmpty
-
-        if cbc.scope.evaluate(BuiltinMacros.ENABLE_BITCODE) && supportsBitcode {
-            // LD_BITCODE_GENERATION_MODE is the linker setting which controls passing bitcode options to the linker; but since we're invoking the linker directly here, rather than the compiler driver, we pass -bitcode_bundle rather than -fembed-bitcode*.
-            commandLine += ["-bitcode_bundle"]
-
-            // If we're generating full bitcode, then we also want to pass -bitcode_verify to make sure all the objects it links against also contain full bitcode.
-            if cbc.scope.evaluate(BuiltinMacros.BITCODE_GENERATION_MODE) == "bitcode" {
-                commandLine += ["-bitcode_verify"]
-            }
-        }
-
         // We do not pass the deployment target to the linker here.  Instead the linker infers the platform and deployment target from the .o files being collected.  We did briefly pass it to the linker to silence a linker warning - if we ever see issues here we should confer with the linker folks to make sure we do the right thing.  See <rdar://problem/51800525> for more about the history here.
 
         let sysroot = cbc.scope.evaluate(BuiltinMacros.SDK_DIR)

Sources/SWBCore/SpecImplementations/Tools/SwiftCompiler.swift

@@ -3061,12 +3061,6 @@ public final class SwiftCompilerSpec : CompilerSpec, SpecIdentifierType, SwiftDi
                     fileMapEntry.indexUnitOutputPath = indexObjectPath.str
                 }
             }
-            let objectFilePrefix = objectFilePath.basenameWithoutSuffix
-            // The bitcode file.
-            if compilationMode.compileSources {
-                let bitcodeFilePath = objectFileDir.join(objectFilePrefix + ".bc")
-                fileMapEntry.llvmBitcode = bitcodeFilePath.str
-            }
             return (objectFilePath, fileMapEntry)
         }
 
@@ -3309,10 +3303,6 @@ public final class SwiftCompilerSpec : CompilerSpec, SpecIdentifierType, SwiftDi
             "-O",
             "-Osize",
 
-            // _Very_ deprecated, but continuing to strip for backwards compatibility
-            "-embed-bitcode",
-            "-embed-bitcode-marker",
-
             // Previews does not use compiler output
             "-parseable-output",
             "-use-frontend-parseable-output",
@@ -3784,7 +3774,6 @@ struct SwiftOutputFileMap: Codable {
     struct Entry: Codable {
         var object: String?
         var indexUnitOutputPath: String?
-        var llvmBitcode: String?
         var remap: String?
         var diagnostics: String?
         var emitModuleDiagnostics: String?
@@ -3798,7 +3787,6 @@ struct SwiftOutputFileMap: Codable {
         enum CodingKeys: String, CodingKey {
             case object
             case indexUnitOutputPath = "index-unit-output-path"
-            case llvmBitcode = "llvm-bc"
             case remap
             case diagnostics
             case emitModuleDiagnostics = "emit-module-diagnostics"