[6.2] Pass -add_mergeable_debug_hook to the linker when linking a mergeable library in a debug (unoptimized) build.

Sources/SWBCore/Settings/BuiltinMacros.swift

@@ -420,6 +420,7 @@ public final class BuiltinMacros {
 
     // MARK: Mergeable libraries macros
 
+    public static let ADD_MERGEABLE_DEBUG_HOOK = BuiltinMacros.declareBooleanMacro("ADD_MERGEABLE_DEBUG_HOOK")
     public static let AUTOMATICALLY_MERGE_DEPENDENCIES = BuiltinMacros.declareBooleanMacro("AUTOMATICALLY_MERGE_DEPENDENCIES")
     public static let MERGEABLE_LIBRARY = BuiltinMacros.declareBooleanMacro("MERGEABLE_LIBRARY")
     public static let DONT_EMBED_REEXPORTED_MERGEABLE_LIBRARIES = BuiltinMacros.declareBooleanMacro("DONT_EMBED_REEXPORTED_MERGEABLE_LIBRARIES")
@@ -1369,6 +1370,7 @@ public final class BuiltinMacros {
         ADDITIONAL_SDK_DIRS,
         AD_HOC_CODE_SIGNING_ALLOWED,
         __AD_HOC_CODE_SIGNING_NOT_ALLOWED_SUPPLEMENTAL_MESSAGE,
+        ADD_MERGEABLE_DEBUG_HOOK,
         AGGREGATE_TRACKED_DOMAINS,
         ALLOW_BUILD_REQUEST_OVERRIDES,
         ALLOW_DISJOINTED_DIRECTORIES_AS_DEPENDENCIES,

Sources/SWBCore/Settings/Settings.swift

@@ -2164,9 +2164,14 @@ private class SettingsBuilder {
                 table.push(BuiltinMacros.MERGE_LINKED_LIBRARIES, literal: true)
             }
 
-            // If this is a mergeable library, then build it as mergeable if this is a release build.
-            if scope.evaluate(BuiltinMacros.MERGEABLE_LIBRARY), !scope.evaluate(BuiltinMacros.IS_UNOPTIMIZED_BUILD) {
-                table.push(BuiltinMacros.MAKE_MERGEABLE, literal: true)
+            // If this is a mergeable library, for a release build we want to build it as mergeable, whereas for a debug build we want to add the mergeable debug hook.
+            if scope.evaluate(BuiltinMacros.MERGEABLE_LIBRARY) {
+                if scope.evaluate(BuiltinMacros.IS_UNOPTIMIZED_BUILD) {
+                    table.push(BuiltinMacros.ADD_MERGEABLE_DEBUG_HOOK, literal: true)
+                }
+                else {
+                    table.push(BuiltinMacros.MAKE_MERGEABLE, literal: true)
+                }
             }
 
             push(table, .exportedForNative)

Sources/SWBTestSupport/CoreBasedTests.swift

@@ -379,6 +379,13 @@ extension CoreBasedTests {
         try await SWBCore.discoveredSwiftCompilerInfo(MockCommandProducer(core: getCore(), productTypeIdentifier: "com.apple.product-type.framework", platform: nil, useStandardExecutableSearchPaths: true, toolchain: nil, fs: PseudoFS()), AlwaysDeferredCoreClientDelegate(), at: toolPath, blocklistsPathOverride: nil)
     }
 
+    package func discoveredLdLinkerInfo(at toolPath: Path) async throws -> DiscoveredLdLinkerToolSpecInfo {
+        guard let info = try await SWBCore.discoveredLinkerToolsInfo(MockCommandProducer(core: getCore(), productTypeIdentifier: "com.apple.product-type.framework", platform: nil, useStandardExecutableSearchPaths: true, toolchain: nil, fs: PseudoFS()), AlwaysDeferredCoreClientDelegate(), at: toolPath) as? DiscoveredLdLinkerToolSpecInfo else {
+            throw StubError.error("Could not get tool spec info for LdLinkerSpec")
+        }
+        return info
+    }
+
     package func discoveredTAPIToolInfo(at toolPath: Path) async throws -> DiscoveredTAPIToolSpecInfo {
         try await SWBCore.discoveredTAPIToolInfo(MockCommandProducer(core: getCore(), productTypeIdentifier: "com.apple.product-type.framework", platform: nil, useStandardExecutableSearchPaths: true, toolchain: nil, fs: PseudoFS()), AlwaysDeferredCoreClientDelegate(), at: toolPath)
     }

Sources/SWBUniversalPlatform/Specs/Ld.xcspec

@@ -665,6 +665,19 @@
                 };
             },
 
+            {   Name = LD_ADD_MERGEABLE_DEBUG_HOOK;
+                Type = Boolean;
+                DefaultValue = "$(ADD_MERGEABLE_DEBUG_HOOK)";
+                CommandLineArgs = {
+                    YES = (
+                        "-Xlinker",
+                        "-add_mergeable_debug_hook",
+                    );
+                    NO = ();
+                };
+                SupportedVersionRanges = ( "1217" );
+            },
+
             {
                 Name = "LD_SHARED_CACHE_ELIGIBLE";
                 Type = Enumeration;

Tests/SWBBuildSystemTests/MergeableLibrariesBuildOperationTests.swift

@@ -26,6 +26,18 @@ import MachO
 
 @Suite(.requireXcode16())
 fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
+
+    private func linkerSupportsMergeableDebugHook() async throws -> Bool {
+        guard let ldPath = try await ldPath else {
+            throw StubError.error("Could not get path for ld linker.")
+        }
+        let info = try await discoveredLdLinkerInfo(at: ldPath)
+        guard let version = info.toolVersion else {
+            throw StubError.error("Could not get version for ld linker at '\(ldPath.str).")
+        }
+        return version >= Version(1217)
+    }
+
     @Test(.requireSDKs(.iOS))
     func automaticMergedFrameworkCreation() async throws {
         try await testAutomaticMergedFrameworkCreation(useAppStoreCodelessFrameworksWorkaround: true)
@@ -164,6 +176,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
             let tester = try await BuildOperationTester(getCore(), testWorkspace, simulated: false)
             let SRCROOT = testWorkspace.sourceRoot.join("aProject")
             let signableTargets: Set<String> = Set(tester.workspace.projects[0].targets.map({ $0.name }))
+            let supportsMergeableDebugHook = try await linkerSupportsMergeableDebugHook()
 
             // Write the source files.
             try await tester.fs.writeFileContents(SRCROOT.join("Sources/Application.swift")) { contents in
@@ -216,6 +229,9 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("SwiftCompile")) { _ in }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("Ld")) { task in
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            if supportsMergeableDebugHook {
+                                task.checkCommandLineContains("-add_mergeable_debug_hook")
+                            }
                             task.checkCommandLineContains(["-o", "\(SYMROOT)/Debug-iphoneos/\(targetName).framework/\(targetName)"])
                         }
                         results.checkTasks(.matchTargetName(targetName), .matchRuleType("Copy")) { _ in /* likely Swift-related */ }
@@ -234,6 +250,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                             task.checkCommandLineContains(["-o", "\(SYMROOT)/Debug-iphoneos/\(targetName).framework/\(targetName)"])
                             task.checkCommandLineDoesNotContain("-merge_framework")
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                         }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("CodeSign"), .matchRuleItemBasename("\(targetName).framework")) { _ in }
                         // Check that the mergeable frameworks' binaries were copied in and re-signed.
@@ -396,6 +413,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("SwiftCompile")) { _ in }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("Ld")) { task in
                             task.checkCommandLineContains("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                             task.checkCommandLineContains(["-o", "\(OBJROOT)/UninstalledProducts/iphoneos/\(targetName).framework/\(targetName)"])
                         }
                         results.checkTasks(.matchTargetName(targetName), .matchRuleType("Copy")) { _ in /* likely Swift-related */ }
@@ -415,6 +433,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                             task.checkCommandLineContains(["-Xlinker", "-merge_framework", "-Xlinker", "FwkTarget2"])
                             task.checkCommandLineContains(["-o", "\(OBJROOT)/UninstalledProducts/iphoneos/\(targetName).framework/\(targetName)"])
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                             task.checkCommandLineDoesNotContain("-no_merge_framework")
                         }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("Strip")) { _ in }
@@ -649,6 +668,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
             let SRCROOT_App = testWorkspace.sourceRoot.join("AppProject")
             let SRCROOT_Fwk = testWorkspace.sourceRoot.join("FwkProject")
             let signableTargets: Set<String> = Set(tester.workspace.projects.flatMap({$0.targets}).map({ $0.name }))
+            let supportsMergeableDebugHook = try await linkerSupportsMergeableDebugHook()
 
             // Write the source files.
             try await tester.fs.writeFileContents(SRCROOT_App.join("Sources/Application.swift")) { contents in
@@ -698,6 +718,9 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("SwiftCompile")) { _ in }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("Ld")) { task in
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            if supportsMergeableDebugHook {
+                                task.checkCommandLineContains("-add_mergeable_debug_hook")
+                            }
                             task.checkCommandLineContains(["-o", "\(SYMROOT)/Config-iphoneos/\(targetName).framework/\(targetName)"])
                         }
                         results.checkTasks(.matchTargetName(targetName), .matchRuleType("Copy")) { _ in /* likely Swift-related */ }
@@ -855,6 +878,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("SwiftCompile")) { _ in }
                         results.checkTask(.matchTargetName(targetName), .matchRuleType("Ld")) { task in
                             task.checkCommandLineContains("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                             task.checkCommandLineContains(["-o", "\(OBJROOT)/UninstalledProducts/iphoneos/\(targetName).framework/\(targetName)"])
                         }
                         results.checkTasks(.matchTargetName(targetName), .matchRuleType("Copy")) { _ in /* likely Swift-related */ }
@@ -876,6 +900,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                             task.checkCommandLineContains(["-Xlinker", "-merge_library", "-Xlinker", "\(OBJROOT)/UninstalledProducts/iphoneos/\(fwkTargetName).framework/\(fwkTargetName)"])
                             task.checkCommandLineContains(["-o", "\(DSTROOT)/Applications/\(targetName).app/\(targetName)"])
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                             task.checkCommandLineDoesNotContain("-no_merge_framework")
                         }
                         // Check that we're excluding the binary when embedding the mergeable targets, but not the merged target.
@@ -1512,6 +1537,7 @@ fileprivate struct MergeableLibrariesBuildOperationTests: CoreBasedTests {
                             task.checkCommandLineContains(["-Xlinker", "-merge-l\(libBaseName)"])
                             task.checkCommandLineContains(["-o", "\(OBJROOT)/UninstalledProducts/iphoneos/\(targetName).framework/\(targetName)"])
                             task.checkCommandLineDoesNotContain("-make_mergeable")
+                            task.checkCommandLineDoesNotContain("-add_mergeable_debug_hook")
                             task.checkCommandLineDoesNotContain("-no_merge_framework")
                         }
                         results.checkTasks(.matchTargetName(targetName), .matchRuleType("Copy")) { _ in /* likely Swift-related */ }