Workaround mingw-gcc LTO ICE by re-adding some dead code...

Not my finest work, but without that code removed in #102179, mingw-gcc 14.2.1 on Fedora 41
(but also confirmed with versions on macOS and WSL) crashes when linking with LTO.

We need to dig deeper to understand the bug, report it upstream and work it around in a
cleaner way. But for now this unblocks building Windows binaries with LTO, and should be
harmless.

platform/ios/export/export_plugin.cpp

@@ -1256,6 +1256,167 @@ struct ExportLibsData {
 	String dest_dir;
 };
 
+bool EditorExportPlatformIOS::_archive_has_arm64(const String &p_path, uint32_t *r_cputype, uint32_t *r_cpusubtype) const {
+	bool has_arm64_image = false;
+	if (FileAccess::exists(p_path)) {
+		if (LipO::is_lipo(p_path)) {
+			// LipO.
+			Ref<LipO> lipo;
+			lipo.instantiate();
+			if (lipo->open_file(p_path)) {
+				for (int i = 0; i < lipo->get_arch_count(); i++) {
+					if (lipo->get_arch_cputype(i) == 0x100000c && lipo->get_arch_cpusubtype(i) == 0) {
+						has_arm64_image = true;
+						break;
+					}
+				}
+			}
+			lipo->close();
+		} else {
+			// Single architecture archive.
+			Ref<FileAccess> sim_f = FileAccess::open(p_path, FileAccess::READ);
+			if (sim_f.is_valid()) {
+				char magic[9] = {};
+				sim_f->get_buffer((uint8_t *)&magic[0], 8);
+				if (String(magic) == String("!<arch>\n")) {
+					while (!sim_f->eof_reached()) {
+						// Read file metadata.
+						char name_short[17] = {};
+						char size_short[11] = {};
+						sim_f->get_buffer((uint8_t *)&name_short[0], 16);
+						sim_f->seek(sim_f->get_position() + 12 + 6 + 6 + 8); // Skip modification time, owner ID, group ID, file mode.
+						sim_f->get_buffer((uint8_t *)&size_short[0], 10);
+						sim_f->seek(sim_f->get_position() + 2); // Skip end marker.
+
+						int64_t file_size = String(size_short).to_int();
+						int64_t next_off = sim_f->get_position() + file_size;
+
+						String name = String(name_short); // Skip extended name.
+						if (name.is_empty() || file_size == 0) {
+							break;
+						}
+						if (name.begins_with("#1/")) {
+							int64_t name_len = String(name_short).replace("#1/", "").to_int();
+							sim_f->seek(sim_f->get_position() + name_len);
+						}
+
+						// Read file content.
+						uint32_t obj_magic = sim_f->get_32();
+
+						bool swap = (obj_magic == 0xcffaedfe || obj_magic == 0xcefaedfe);
+						if (obj_magic == 0xcefaedfe || obj_magic == 0xfeedface || obj_magic == 0xcffaedfe || obj_magic == 0xfeedfacf) {
+							uint32_t cputype = sim_f->get_32();
+							uint32_t cpusubtype = sim_f->get_32();
+							if (swap) {
+								cputype = BSWAP32(cputype);
+								cpusubtype = BSWAP32(cpusubtype);
+							}
+							if (r_cputype) {
+								*r_cputype = cputype;
+							}
+							if (r_cpusubtype) {
+								*r_cpusubtype = cpusubtype;
+							}
+							if (cputype == 0x100000c && cpusubtype == 0) {
+								has_arm64_image = true;
+							}
+							break;
+						}
+						sim_f->seek(next_off);
+					}
+				}
+				sim_f->close();
+			}
+		}
+	}
+	return has_arm64_image;
+}
+
+int EditorExportPlatformIOS::_archive_convert_to_simulator(const String &p_path) const {
+	int commands_patched = 0;
+	Ref<FileAccess> sim_f = FileAccess::open(p_path, FileAccess::READ_WRITE);
+	if (sim_f.is_valid()) {
+		char magic[9] = {};
+		sim_f->get_buffer((uint8_t *)&magic[0], 8);
+		if (String(magic) == String("!<arch>\n")) {
+			while (!sim_f->eof_reached()) {
+				// Read file metadata.
+				char name_short[17] = {};
+				char size_short[11] = {};
+				sim_f->get_buffer((uint8_t *)&name_short[0], 16);
+				sim_f->seek(sim_f->get_position() + 12 + 6 + 6 + 8); // Skip modification time, owner ID, group ID, file mode.
+				sim_f->get_buffer((uint8_t *)&size_short[0], 10);
+				sim_f->seek(sim_f->get_position() + 2); // Skip end marker.
+
+				int64_t file_size = String(size_short).to_int();
+				int64_t next_off = sim_f->get_position() + file_size;
+
+				String name = String(name_short); // Skip extended name.
+				if (name.is_empty() || file_size == 0) {
+					break;
+				}
+				if (name.begins_with("#1/")) {
+					int64_t name_len = String(name_short).replace("#1/", "").to_int();
+					sim_f->seek(sim_f->get_position() + name_len);
+				}
+
+				// Read file content.
+				uint32_t obj_magic = sim_f->get_32();
+
+				bool swap = (obj_magic == 0xcffaedfe || obj_magic == 0xcefaedfe);
+				if (obj_magic == 0xcefaedfe || obj_magic == 0xfeedface || obj_magic == 0xcffaedfe || obj_magic == 0xfeedfacf) {
+					uint32_t cputype = sim_f->get_32();
+					uint32_t cpusubtype = sim_f->get_32();
+					uint32_t filetype = sim_f->get_32();
+					uint32_t ncmds = sim_f->get_32();
+					sim_f->get_32(); // Commands total size.
+					sim_f->get_32(); // Commands flags.
+					if (obj_magic == 0xcffaedfe || obj_magic == 0xfeedfacf) {
+						sim_f->get_32(); // Reserved, 64-bit only.
+					}
+					if (swap) {
+						ncmds = BSWAP32(ncmds);
+						cputype = BSWAP32(cputype);
+						cpusubtype = BSWAP32(cpusubtype);
+						filetype = BSWAP32(filetype);
+					}
+					if (cputype == 0x100000C && cpusubtype == 0 && filetype == 1) {
+						// ARM64, object file.
+						for (uint32_t i = 0; i < ncmds; i++) {
+							int64_t cmdofs = sim_f->get_position();
+							uint32_t cmdid = sim_f->get_32();
+							uint32_t cmdsize = sim_f->get_32();
+							if (swap) {
+								cmdid = BSWAP32(cmdid);
+								cmdsize = BSWAP32(cmdsize);
+							}
+							if (cmdid == MachO::LoadCommandID::LC_BUILD_VERSION) {
+								int64_t platform = sim_f->get_32();
+								if (swap) {
+									platform = BSWAP32(platform);
+								}
+								if (platform == MachO::PlatformID::PLATFORM_IOS) {
+									sim_f->seek(cmdofs + 4 + 4);
+									uint32_t new_id = MachO::PlatformID::PLATFORM_IOSSIMULATOR;
+									if (swap) {
+										new_id = BSWAP32(new_id);
+									}
+									sim_f->store_32(new_id);
+									commands_patched++;
+								}
+							}
+							sim_f->seek(cmdofs + cmdsize);
+						}
+					}
+				}
+				sim_f->seek(next_off);
+			}
+		}
+		sim_f->close();
+	}
+	return commands_patched;
+}
+
 void EditorExportPlatformIOS::_check_xcframework_content(const String &p_path, int &r_total_libs, int &r_static_libs, int &r_dylibs, int &r_frameworks) const {
 	Ref<PList> plist;
 	plist.instantiate();
@@ -2260,6 +2421,82 @@ Error EditorExportPlatformIOS::_export_project_helper(const Ref<EditorExportPres
 		return ERR_FILE_NOT_FOUND;
 	}
 
+	// HACK: We don't want to run the simulator library generation code anymore after GH-102179, but removing it
+	// triggers an internal compiler error with latest mingw-gcc... For now we bring it back as a workaround
+	// with a condition that should never be true (that project setting doesn't exist).
+
+	// Check and generate missing ARM64 simulator library.
+	if (ProjectSettings::get_singleton()->has_setting("__dummy_setting_blame_akien_if_you_define_this_somehow")) {
+		String sim_lib_path = dest_dir + String(binary_name + ".xcframework").path_join("ios-arm64_x86_64-simulator").path_join("libgodot.a");
+		String dev_lib_path = dest_dir + String(binary_name + ".xcframework").path_join("ios-arm64").path_join("libgodot.a");
+		String tmp_lib_path = EditorPaths::get_singleton()->get_temp_dir().path_join(binary_name + "_lipo_");
+		uint32_t cputype = 0;
+		uint32_t cpusubtype = 0;
+		if (!_archive_has_arm64(sim_lib_path, &cputype, &cpusubtype) && _archive_has_arm64(dev_lib_path) && FileAccess::exists(dev_lib_path)) {
+			add_message(EXPORT_MESSAGE_INFO, TTR("Export"), TTR("ARM64 simulator library, generating from device library."));
+
+			Vector<String> tmp_lib_files;
+			Vector<Vector2i> tmp_lib_cputypes;
+			// Extract/copy simulator lib.
+			if (FileAccess::exists(sim_lib_path)) {
+				if (LipO::is_lipo(sim_lib_path)) {
+					Ref<LipO> lipo;
+					lipo.instantiate();
+					if (lipo->open_file(sim_lib_path)) {
+						for (int i = 0; i < lipo->get_arch_count(); i++) {
+							const String &f_name = tmp_lib_path + itos(tmp_lib_files.size());
+							lipo->extract_arch(i, f_name);
+							tmp_lib_files.push_back(f_name);
+							tmp_lib_cputypes.push_back(Vector2i(lipo->get_arch_cputype(i), lipo->get_arch_cpusubtype(i)));
+						}
+					}
+				} else {
+					const String &f_name = tmp_lib_path + itos(tmp_lib_files.size());
+					tmp_app_path->copy(sim_lib_path, f_name);
+					tmp_lib_files.push_back(f_name);
+					tmp_lib_cputypes.push_back(Vector2i(cputype, cpusubtype));
+				}
+			}
+			// Copy device lib.
+			if (LipO::is_lipo(dev_lib_path)) {
+				Ref<LipO> lipo;
+				lipo.instantiate();
+				if (lipo->open_file(dev_lib_path)) {
+					for (int i = 0; i < lipo->get_arch_count(); i++) {
+						if (lipo->get_arch_cputype(i) == 0x100000c && lipo->get_arch_cpusubtype(i) == 0) {
+							const String &f_name = tmp_lib_path + itos(tmp_lib_files.size());
+							lipo->extract_arch(i, f_name);
+							tmp_lib_files.push_back(f_name);
+							tmp_lib_cputypes.push_back(Vector2i(0x100000c, 0)); // ARM64.
+							break;
+						}
+					}
+				}
+			} else {
+				const String &f_name = tmp_lib_path + itos(tmp_lib_files.size());
+				tmp_app_path->copy(dev_lib_path, f_name);
+				tmp_lib_files.push_back(f_name);
+				tmp_lib_cputypes.push_back(Vector2i(0x100000c, 0)); // ARM64.
+			}
+
+			// Patch device lib.
+			int patch_count = _archive_convert_to_simulator(tmp_lib_path + itos(tmp_lib_files.size() - 1));
+			if (patch_count == 0) {
+				add_message(EXPORT_MESSAGE_WARNING, TTR("Export"), TTR("Unable to generate ARM64 simulator library."));
+			} else {
+				// Repack.
+				Ref<LipO> lipo;
+				lipo.instantiate();
+				lipo->create_file(sim_lib_path, tmp_lib_files, tmp_lib_cputypes);
+			}
+
+			// Cleanup.
+			for (const String &E : tmp_lib_files) {
+				tmp_app_path->remove(E);
+			}
+		}
+	}
+
 	// Generate translations files.
 
 	Dictionary appnames = GLOBAL_GET("application/config/name_localized");

platform/ios/export/export_plugin.h

@@ -136,6 +136,8 @@ class EditorExportPlatformIOS : public EditorExportPlatform {
 	Vector<ExportArchitecture> _get_supported_architectures() const;
 	Vector<String> _get_preset_architectures(const Ref<EditorExportPreset> &p_preset) const;
 
+	bool _archive_has_arm64(const String &p_path, uint32_t *r_cputype = nullptr, uint32_t *r_cpusubtype = nullptr) const;
+	int _archive_convert_to_simulator(const String &p_path) const;
 	void _check_xcframework_content(const String &p_path, int &r_total_libs, int &r_static_libs, int &r_dylibs, int &r_frameworks) const;
 	Error _convert_to_framework(const String &p_source, const String &p_destination, const String &p_id) const;