Generate native Preview compile and link phases

tools/generators/pbxnativetargets/README.md

@@ -162,7 +162,7 @@ Here is an example output:
 				PRODUCT_NAME = pbxtargetdependencies_tests;
 				SDKROOT = macosx;
 				SUPPORTED_PLATFORMS = macosx;
-				SWIFT_COMPILATION_MODE = wholemodule;
+				SWIFT_COMPILATION_MODE = "$(BAZEL_SWIFT_COMPILATION_MODE)";
 				TARGET_NAME = pbxtargetdependencies_tests;
 			};
 			name = Release;
@@ -255,7 +255,7 @@ Here is an example output:
 				PRODUCT_NAME = XCTestDynamicOverlay;
 				SDKROOT = macosx;
 				SUPPORTED_PLATFORMS = macosx;
-				SWIFT_COMPILATION_MODE = wholemodule;
+				SWIFT_COMPILATION_MODE = "$(BAZEL_SWIFT_COMPILATION_MODE)";
 				TARGET_NAME = XCTestDynamicOverlay;
 			};
 			name = Release;

tools/generators/pbxnativetargets/src/Generator/CalculatePlatformVariantBuildSettings.swift

@@ -22,10 +22,10 @@ extension Generator {
             platformVariant: Target.PlatformVariant
         ) async throws -> [PlatformVariantBuildSetting] {
             return try await callable(
-                /*isBundle:*/ isBundle,
-                /*originalProductBasename:*/ originalProductBasename,
-                /*productType:*/ productType,
-                /*platformVariant:*/ platformVariant
+                /* isBundle: */ isBundle,
+                /* originalProductBasename: */ originalProductBasename,
+                /* productType: */ productType,
+                /* platformVariant: */ platformVariant
             )
         }
     }
@@ -146,6 +146,14 @@ extension Generator.CalculatePlatformVariantBuildSettings {
         }
 
         if let testHost = platformVariant.unitTestHost {
+            // Let Xcode select the host's native image, including its debug
+            // dylib. Bazel's bundle_loader points to a different executable.
+            buildSettings += [
+                .init(key: "BUNDLE_LOADER", value: "$(BAZEL_BUNDLE_LOADER__$(BAZEL_NATIVE_PREVIEWS))".pbxProjEscaped),
+                .init(key: "BAZEL_BUNDLE_LOADER__", value: #""""#),
+                .init(key: "BAZEL_BUNDLE_LOADER__NO", value: #""""#),
+                .init(key: "BAZEL_BUNDLE_LOADER__YES", value: "$(TEST_HOST)".pbxProjEscaped),
+            ]
             buildSettings.append(
                 .init(
                     key: "TARGET_BUILD_DIR",
@@ -165,6 +173,16 @@ extension Generator.CalculatePlatformVariantBuildSettings {
         }
 
         if let linkParams = platformVariant.linkParams {
+            if platformVariant.platform == .iOSSimulator {
+                buildSettings.append(
+                    .init(
+                        key: "LIBRARY_SEARCH_PATHS",
+                        value:
+                            #""$(inherited) $(PREVIEW_SDK_LIBRARY_SEARCH_PATH)""#
+                    )
+                )
+            }
+
             // Drop the `bazel-out` prefix since we use the env var for this
             // portion of the path
             buildSettings.append(
@@ -175,15 +193,56 @@ extension Generator.CalculatePlatformVariantBuildSettings {
 """#
                 )
             )
-            buildSettings.append(
-                .init(
-                    key: "OTHER_LDFLAGS",
-                    value: #""@$(DERIVED_FILE_DIR)/link.params""#
+            if productType == .staticLibrary {
+                // Index preparation requests compile/index inputs, not bl.
+                // Reuse the existing input in inactive configurations so the
+                // phase never requires an unprepared runtime-policy sidecar.
+                buildSettings += [
+                    .init(
+                        key: "BAZEL_PREVIEW_RUNTIME_POLICY_SUFFIX",
+                        value: (
+                            "$(BAZEL_PREVIEW_RUNTIME_POLICY_SUFFIX_$(ACTION)_" +
+                            "$(BAZEL_NATIVE_PREVIEWS)_$(INDEX_ENABLE_BUILD_ARENA))"
+                        ).pbxProjEscaped
+                    ),
+                    .init(key: "BAZEL_PREVIEW_RUNTIME_POLICY_SUFFIX_build_YES_", value: ".runtime.json"),
+                    .init(key: "BAZEL_PREVIEW_RUNTIME_POLICY_SUFFIX_build_YES_NO", value: ".runtime.json"),
+                ]
+                // Xcode 26 derives a static-library target's Preview link
+                // closure from its Libtool task, not from OTHER_LDFLAGS.
+                // Create Link Dependencies truncates this response file for
+                // ordinary builds, preserving normal archive membership.
+                buildSettings.append(
+                    .init(
+                        key: "OTHER_LIBTOOLFLAGS",
+                        value: #""@$(DERIVED_FILE_DIR)/link.params""#
+                    )
                 )
-            )
+            } else {
+                buildSettings.append(
+                    .init(
+                        key: "OTHER_LDFLAGS",
+                        value: #""-working-directory $(PROJECT_DIR) @$(DERIVED_FILE_DIR)/link.params""#
+                    )
+                )
+            }
         }
 
-        buildSettings.append(contentsOf: platformVariant.buildSettingsFromFile)
+        buildSettings.append(
+            contentsOf: platformVariant.buildSettingsFromFile.map { buildSetting in
+                guard platformVariant.platform.supportsXcodePreviews,
+                      buildSetting.key == "SWIFT_COMPILATION_MODE",
+                      buildSetting.value == "wholemodule"
+                else {
+                    return buildSetting
+                }
+
+                // Unlike ENABLE_XOJIT_PREVIEWS, this configuration-scoped value
+                // is fixed before Preview eligibility checks. Ordinary builds
+                // retain WMO; only an opted-in Preview configuration is incremental.
+                return .init(key: buildSetting.key, value: #""$(BAZEL_SWIFT_COMPILATION_MODE)""#)
+            }
+        )
 
         return buildSettings
     }
@@ -216,6 +275,24 @@ private extension Platform.OS {
     }
 }
 
+private extension Platform {
+    var supportsXcodePreviews: Bool {
+        switch self {
+        case .macOS,
+                .iOSSimulator,
+                .tvOSSimulator,
+                .visionOSSimulator,
+                .watchOSSimulator:
+            return true
+        case .iOSDevice,
+                .tvOSDevice,
+                .visionOSDevice,
+                .watchOSDevice:
+            return false
+        }
+    }
+}
+
 private extension PBXProductType {
     var fileExtension: String? {
         switch self {

tools/generators/pbxnativetargets/src/Generator/CalculateXcodeConfigurationBuildSettings.swift

@@ -19,8 +19,8 @@ extension Generator {
             allConditionalFiles: Set<BazelPath>
         ) -> [BuildSetting] {
             return callable(
-                /*platformBuildSettings:*/ platformBuildSettings,
-                /*allConditionalFiles:*/ allConditionalFiles
+                /* platformBuildSettings: */ platformBuildSettings,
+                /* allConditionalFiles: */ allConditionalFiles
             )
         }
     }
@@ -71,7 +71,7 @@ extension Generator.CalculateXcodeConfigurationBuildSettings {
                             // Lots of code just to quote and `.pbxProjEscaped`
                             // the paths
                             platformBuildSettings.conditionalFiles
-                                .map { $0.path.quoteIfNeeded }
+                                .map(\.path.quoteIfNeeded)
                                 // TODO: See if we can not sort, or sort earlier
                                 .sorted()
                                 .joined(separator: " ")
@@ -101,7 +101,7 @@ extension Generator.CalculateXcodeConfigurationBuildSettings {
         excludedSourceFileNames.append(
             contentsOf: allConditionalFiles
                 .subtracting(conditionalFiles)
-                .map { $0.path.pbxProjEscaped }
+                .map(\.path.pbxProjEscaped)
         )
 
         // Set configuration-wide conditional files

tools/generators/pbxnativetargets/src/Generator/CreateBuildPhases.swift

@@ -204,7 +204,8 @@ extension Generator.CreateBuildPhases {
             buildPhases.append(
                 createCreateLinkDependenciesBuildPhaseObject(
                     subIdentifier: identifier.subIdentifier,
-                    hasCompileStub: hasCompileStub
+                    hasCompileStub: hasCompileStub,
+                    isStaticLibrary: productType == .staticLibrary
                 )
             )
         }

tools/generators/pbxnativetargets/src/Generator/CreateCreateLinkDependenciesBuildPhaseObject.swift

@@ -16,11 +16,13 @@ extension Generator {
         /// target.
         func callAsFunction(
             subIdentifier: Identifiers.Targets.SubIdentifier,
-            hasCompileStub: Bool
+            hasCompileStub: Bool,
+            isStaticLibrary: Bool = false
         ) -> Object {
             return callable(
-                /*subIdentifier:*/ subIdentifier,
-                /*hasCompileStub:*/ hasCompileStub
+                /* subIdentifier: */ subIdentifier,
+                /* hasCompileStub: */ hasCompileStub,
+                /* isStaticLibrary: */ isStaticLibrary
             )
         }
     }
@@ -31,25 +33,68 @@ extension Generator {
 extension Generator.CreateCreateLinkDependenciesBuildPhaseObject {
     typealias Callable = (
         _ subIdentifier: Identifiers.Targets.SubIdentifier,
-        _ hasCompileStub: Bool
+        _ hasCompileStub: Bool,
+        _ isStaticLibrary: Bool
     ) -> Object
 
     static func defaultCallable(
         subIdentifier: Identifiers.Targets.SubIdentifier,
-        hasCompileStub: Bool
+        hasCompileStub: Bool,
+        isStaticLibrary: Bool = false
     ) -> Object {
+        let runtimeAction = isStaticLibrary ? #"""
+if [[ "${BAZEL_NATIVE_PREVIEWS:-}" == "YES" && "${ACTION:-}" == build ]]; then
+  # Script phases have CURRENT_ARCH=undefined_arch. Use the selected target,
+  # never the host architecture or an unrelated ambient toolchain directory.
+  # Explicit exit is necessary: macOS sh can report success for a failed
+  # parameter expansion when an EXIT trap is installed.
+  for runtime_setting in ARCHS LLVM_TARGET_TRIPLE_VENDOR LLVM_TARGET_TRIPLE_OS_VERSION; do
+    if [[ -z "${!runtime_setting:-}" ]]; then
+      echo "error: Missing Preview build setting $runtime_setting" >&2
+      exit 1
+    fi
+  done
+  read -r -a runtime_archs <<< "$ARCHS"
+  if [[ "${#runtime_archs[@]}" != 1 ]]; then
+    echo "error: Preview runtime planning requires exactly one ARCHS value: $ARCHS" >&2
+    exit 1
+  fi
+  runtime_target="${runtime_archs[0]}-${LLVM_TARGET_TRIPLE_VENDOR}-${LLVM_TARGET_TRIPLE_OS_VERSION}"
+  runtime_target+="${LLVM_TARGET_TRIPLE_SUFFIX:-}"
+  /usr/bin/python3 "$BAZEL_INTEGRATION_DIR/preview_runtime_link_params.py" \
+    --driver "${LD:-}" \
+    --sdk "${SDK_DIR:-}" \
+    --target "$runtime_target" \
+    --swift-profile "${BAZEL_PREVIEW_SWIFT_PROFILE:-NO}" \
+    --driver-policy-file "$SCRIPT_INPUT_FILE_1" >> "$link_params_tmp"
+fi
+
+"""# : ""
         let action = #"""
+readonly link_params_tmp="$(mktemp "$SCRIPT_OUTPUT_FILE_0.tmp.XXXXXX")"
+trap 'rm -f "$link_params_tmp"' EXIT
 perl -pe 's/\$(\()?([a-zA-Z_]\w*)(?(1)\))/$ENV{$2}/g' \
-  "$SCRIPT_INPUT_FILE_0" > "$SCRIPT_OUTPUT_FILE_0"
+  < "$SCRIPT_INPUT_FILE_0" > "$link_params_tmp"
+\#(runtimeAction)\#
+chmod 0644 "$link_params_tmp"
+mv -f "$link_params_tmp" "$SCRIPT_OUTPUT_FILE_0"
+trap - EXIT
 """#
+        let indexGuard = isStaticLibrary
+            ? #"[[ "${ACTION:-}" != indexbuild && "${INDEX_ENABLE_BUILD_ARENA:-}" != YES ]] && "#
+            : ""
         var shellScriptComponents: [String] = [
             #"""
 set -euo pipefail
 
-if [[ "${ENABLE_PREVIEWS:-}" == "YES" ]]; then
+if \#(indexGuard)\#
+[[ "${ENABLE_PREVIEWS:-}" == "YES" || \
+      "${BAZEL_NATIVE_PREVIEWS:-}" == "YES" ]]; then
 \#(action)
 else
-  touch "$SCRIPT_OUTPUT_FILE_0"
+  # A prior Preview build may have populated this response file. Truncate it
+  # so ordinary linker and Libtool tasks cannot consume stale Preview inputs.
+  : > "$SCRIPT_OUTPUT_FILE_0"
 fi
 
 """#,
@@ -58,6 +103,13 @@ fi
         var outputPaths = [#"""
 				"$(DERIVED_FILE_DIR)/link.params",
 """#]
+        let runtimeInputs = isStaticLibrary ? #"""
+				"$(LINK_PARAMS_FILE)$(BAZEL_PREVIEW_RUNTIME_POLICY_SUFFIX)",
+				"$(BAZEL_INTEGRATION_DIR)/preview_runtime_link_params.py",
+				"$(LD)",
+				"$(SDK_DIR)/SDKSettings.plist",
+
+"""# : ""
         if hasCompileStub {
             outputPaths.append(#"""
 				"$(DERIVED_FILE_DIR)/_CompileStub_.m",
@@ -77,6 +129,7 @@ touch "$SCRIPT_OUTPUT_FILE_1"
 			);
 			inputPaths = (
 				"$(LINK_PARAMS_FILE)",
+\#(runtimeInputs)\#
 			);
 			name = "Create Link Dependencies";
 			outputPaths = (