[cmake] Remove LLVM_ENABLE_NEW_PASS_MANAGER cmake option

[nikic]

Summary

Or rather, error out if it is set to something other than ON. This removes the ability to enable the legacy pass manager by default, but does not remove the ability to explicitly enable it through various flags like -flegacy-pass-manager or -enable-new-pm=0.

I checked, and our test suite definitely doesn't pass with LLVM_ENABLE_NEW_PASS_MANAGER=OFF anymore.

[aeubanks]

thanks!

[MaskRay]

LGTM.

lld/ELF/Driver.cpp

1106

clang-format

[asbirlea]

Thank you!

clang/include/clang/Driver/Options.td

defm jmc : BoolFOption<"jmc",
   CodeGenOpts<"JMCInstrument">, DefaultFalse,
   PosFlag<SetTrue, [CC1Option], "Enable just-my-code debugging">,
   NegFlag<SetFalse>>;
 def fglobal_isel : Flag<["-"], "fglobal-isel">, Group<f_clang_Group>,
   HelpText<"Enables the global instruction selector">;
 def fexperimental_isel : Flag<["-"], "fexperimental-isel">, Group<f_clang_Group>,
   Alias<fglobal_isel>;
 defm legacy_pass_manager : BoolOption<"f", "legacy-pass-manager",
-  CodeGenOpts<"LegacyPassManager">, Default<"!static_cast<unsigned>(LLVM_ENABLE_NEW_PASS_MANAGER)">,
+  CodeGenOpts<"LegacyPassManager">, DefaultFalse,
   PosFlag<SetTrue, [], "Use the legacy pass manager in LLVM (deprecated, to be removed in a future release)">,
   NegFlag<SetFalse, [], "Use the new pass manager in LLVM">,
   BothFlags<[CC1Option]>>, Group<f_clang_Group>;
 def fexperimental_new_pass_manager : Flag<["-"], "fexperimental-new-pass-manager">,
   Group<f_clang_Group>, Flags<[CC1Option]>, Alias<fno_legacy_pass_manager>;
 def fno_experimental_new_pass_manager : Flag<["-"], "fno-experimental-new-pass-manager">,
   Group<f_clang_Group>, Flags<[CC1Option,NoDriverOption]>, Alias<flegacy_pass_manager>;
 def fexperimental_strict_floating_point : Flag<["-"], "fexperimental-strict-floating-point">,

clang/test/CMakeLists.txt

 # Test runner infrastructure for Clang. This configures the Clang test trees
 # for use by Lit, and delegates to LLVM's lit test handlers.
 
 llvm_canonicalize_cmake_booleans(
   CLANG_BUILD_EXAMPLES
   CLANG_DEFAULT_PIE_ON_LINUX
   CLANG_ENABLE_ARCMT
   CLANG_ENABLE_STATIC_ANALYZER
   CLANG_PLUGIN_SUPPORT
   CLANG_SPAWN_CC1
   ENABLE_BACKTRACES
-  LLVM_ENABLE_NEW_PASS_MANAGER
   LLVM_ENABLE_ZLIB
   LLVM_ENABLE_PER_TARGET_RUNTIME_DIR
   LLVM_ENABLE_THREADS
   LLVM_WITH_Z3
   )
 
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in

clang/test/lit.cfg.py

 #
 if config.clang_default_cxx_stdlib != '':
     config.available_features.add('default-cxx-stdlib-set')
 
 # As of 2011.08, crash-recovery tests still do not pass on FreeBSD.
 if platform.system() not in ['FreeBSD']:
     config.available_features.add('crash-recovery')
 
-# Support for new pass manager.
-if config.enable_experimental_new_pass_manager:
-    config.available_features.add('experimental-new-pass-manager')
-
 # ANSI escape sequences in non-dumb terminal
 if platform.system() not in ['Windows']:
     config.available_features.add('ansi-escape-sequences')
 
 # Capability to print utf8 to the terminal.
 # Windows expects codepage, unless Wide API.
 if platform.system() not in ['Windows']:
     config.available_features.add('utf8-capable-terminal')

clang/test/lit.site.cfg.py.in

 config.clang_arcmt = @CLANG_ENABLE_ARCMT@
 config.clang_default_pie_on_linux = @CLANG_DEFAULT_PIE_ON_LINUX@
 config.clang_default_cxx_stdlib = "@CLANG_DEFAULT_CXX_STDLIB@"
 config.clang_staticanalyzer = @CLANG_ENABLE_STATIC_ANALYZER@
 config.clang_staticanalyzer_z3 = @LLVM_WITH_Z3@
 config.clang_examples = @CLANG_BUILD_EXAMPLES@
 config.enable_shared = @ENABLE_SHARED@
 config.enable_backtrace = @ENABLE_BACKTRACES@
-config.enable_experimental_new_pass_manager = @LLVM_ENABLE_NEW_PASS_MANAGER@
 config.enable_threads = @LLVM_ENABLE_THREADS@
 config.host_arch = "@HOST_ARCH@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.use_z3_solver = lit_config.params.get('USE_Z3_SOLVER', "@USE_Z3_SOLVER@")
 config.has_plugins = @CLANG_PLUGIN_SUPPORT@
 config.clang_vendor_uti = "@CLANG_VENDOR_UTI@"
 config.llvm_external_lit = path(r"@LLVM_EXTERNAL_LIT@")
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 
 # Let the main config do the real work.
 lit_config.load_config(
     config, os.path.join(config.clang_src_dir, "test/lit.cfg.py"))

clang/unittests/Frontend/CompilerInvocationTest.cpp

TEST_F(CommandLineTest, BoolOptionDefaultFalsePresentNegReset) {
   ASSERT_FALSE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
   ASSERT_FALSE(Invocation.getCodeGenOpts().CodeViewGHash);
 }
 
 // Boolean option with a keypath that defaults to an arbitrary expression.
 // The flag with positive spelling can set the keypath to true.
 // The flag with negative spelling can set the keypath to false.
 
-static constexpr unsigned PassManagerDefault =
-    !static_cast<unsigned>(LLVM_ENABLE_NEW_PASS_MANAGER);
-
-static constexpr const char *PassManagerResetByFlag =
-    LLVM_ENABLE_NEW_PASS_MANAGER ? "-fno-legacy-pass-manager"
-                                 : "-flegacy-pass-manager";
-
-static constexpr const char *PassManagerChangedByFlag =
-    LLVM_ENABLE_NEW_PASS_MANAGER ? "-flegacy-pass-manager"
-                                 : "-fno-legacy-pass-manager";
-
 TEST_F(CommandLineTest, BoolOptionDefaultArbitraryTwoFlagsPresentNone) {
   const char *Args = {""};
 
   ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
-  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, PassManagerDefault);
+  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, false);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq(PassManagerResetByFlag))));
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq(PassManagerChangedByFlag))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-legacy-pass-manager"))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-flegacy-pass-manager"))));
 }
 
 TEST_F(CommandLineTest, BoolOptionDefaultArbitraryTwoFlagsPresentChange) {
-  const char *Args[] = {PassManagerChangedByFlag};
+  const char *Args[] = {"-flegacy-pass-manager"};
 
   ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
-  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, !PassManagerDefault);
+  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, true);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
-  ASSERT_THAT(GeneratedArgs, Contains(StrEq(PassManagerChangedByFlag)));
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq(PassManagerResetByFlag))));
+  ASSERT_THAT(GeneratedArgs, Contains(StrEq("-flegacy-pass-manager")));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-legacy-pass-manager"))));
 }
 
 TEST_F(CommandLineTest, BoolOptionDefaultArbitraryTwoFlagsPresentReset) {
-  const char *Args[] = {PassManagerResetByFlag};
+  const char *Args[] = {"-fno-legacy-pass-manager"};
 
   ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
-  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, PassManagerDefault);
+  ASSERT_EQ(Invocation.getCodeGenOpts().LegacyPassManager, false);
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq(PassManagerResetByFlag))));
-  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq(PassManagerChangedByFlag))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-legacy-pass-manager"))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-flegacy-pass-manager"))));
 }
 
 // Boolean option that gets the CC1Option flag from a let statement (which
 // is applied **after** the record is defined):
 //
 //   let Flags = [CC1Option] in {
 //     defm option : BoolOption<...>;
 //   }

lld/COFF/Driver.cpp

if (auto *arg = args.getLastArg(OPT_implib))
     config->implib = arg->getValue();
 
   // Handle /opt.
   bool doGC = debug == DebugKind::None || args.hasArg(OPT_profile);
   Optional<ICFLevel> icfLevel = None;
   if (args.hasArg(OPT_profile))
     icfLevel = ICFLevel::None;
   unsigned tailMerge = 1;
-  bool ltoNewPM = LLVM_ENABLE_NEW_PASS_MANAGER;
+  bool ltoNewPM = true;
   bool ltoDebugPM = false;
   for (auto *arg : args.filtered(OPT_opt)) {
     std::string str = StringRef(arg->getValue()).lower();
     SmallVector<StringRef, 1> vec;
     StringRef(str).split(vec, ',');
     for (StringRef s : vec) {
       if (s == "ref") {
         doGC = true;

lld/ELF/Driver.cpp

static void readConfigs(opt::InputArgList &args) {
   config->init = args.getLastArgValue(OPT_init, "_init");
   config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
   config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
   config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
                                             OPT_no_lto_pgo_warn_mismatch, true);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
   config->ltoNewPassManager =
       args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
-                   LLVM_ENABLE_NEW_PASS_MANAGER);
+                   true);
   config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
   config->ltoWholeProgramVisibility =
       args.hasFlag(OPT_lto_whole_program_visibility,
                    OPT_no_lto_whole_program_visibility, false);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
   config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
   config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);

lld/MachO/Config.h

struct Configuration {
   bool archMultiple = false;
   bool exportDynamic = false;
   bool forceLoadObjC = false;
   bool forceLoadSwift = false;
   bool staticLink = false;
   bool implicitDylibs = false;
   bool isPic = false;
   bool headerPadMaxInstallNames = false;
-  bool ltoNewPassManager = LLVM_ENABLE_NEW_PASS_MANAGER;
+  bool ltoNewPassManager = true;
   bool markDeadStrippableDylib = false;
   bool printDylibSearch = false;
   bool printEachFile = false;
   bool printWhyLoad = false;
   bool searchDylibsFirst = false;
   bool saveTemps = false;
   bool adhocCodesign = false;
   bool emitFunctionStarts = false;

lld/MachO/Driver.cpp

addFile(arg->getValue(), ForceLoad::Default, /*isLazy=*/false,
             /*isBundleLoader=*/true);
   }
   if (const Arg *arg = args.getLastArg(OPT_umbrella)) {
     if (config->outputType != MH_DYLIB)
       warn("-umbrella used, but not creating dylib");
     config->umbrella = arg->getValue();
   }
   config->ltoObjPath = args.getLastArgValue(OPT_object_path_lto);
   config->ltoNewPassManager =
       args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
-                   LLVM_ENABLE_NEW_PASS_MANAGER);
+                   true);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   if (config->ltoo > 3)
     error("--lto-O: invalid optimization level: " + Twine(config->ltoo));
   config->thinLTOCacheDir = args.getLastArgValue(OPT_cache_path_lto);
   config->thinLTOCachePolicy = getLTOCachePolicy(args);
   config->runtimePaths = args::getStrings(args, OPT_rpath);
   config->allLoad = args.hasFlag(OPT_all_load, OPT_noall_load, false);
   config->archMultiple = args.hasArg(OPT_arch_multiple);

lld/wasm/Driver.cpp

static void readConfigs(opt::InputArgList &args) {
   config->exportTable = args.hasArg(OPT_export_table);
   config->growableTable = args.hasArg(OPT_growable_table);
   config->importMemory = args.hasArg(OPT_import_memory);
   config->sharedMemory = args.hasArg(OPT_shared_memory);
   config->importTable = args.hasArg(OPT_import_table);
   config->importUndefined = args.hasArg(OPT_import_undefined);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
   config->ltoNewPassManager =
       args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
-                   LLVM_ENABLE_NEW_PASS_MANAGER);
+                   true);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->mapFile = args.getLastArgValue(OPT_Map);
   config->optimize = args::getInteger(args, OPT_O, 1);
   config->outputFile = args.getLastArgValue(OPT_o);
   config->relocatable = args.hasArg(OPT_relocatable);
   config->gcSections =
       args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, !config->relocatable);
   config->mergeDataSegments =

llvm/CMakeLists.txt

 else()
   set(LLVM_ENABLE_PLUGINS_default ${LLVM_ENABLE_PIC})
 endif()
 option(LLVM_ENABLE_PLUGINS "Enable plugin support" ${LLVM_ENABLE_PLUGINS_default})
 
 set(LLVM_ENABLE_NEW_PASS_MANAGER TRUE CACHE BOOL
   "Enable the new pass manager by default.")
 if(NOT LLVM_ENABLE_NEW_PASS_MANAGER)
-  message(WARNING "Using the legacy pass manager for the optimization pipeline"
-                  " is deprecated. The functionality will degrade over time and"
-                  " be removed in a future release.")
+  message(FATAL_ERROR "Enabling the legacy pass manager on the cmake level is"
+                      " no longer supported.")
 endif()
 
 include(HandleLLVMOptions)
 
 find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION} REQUIRED
     COMPONENTS Interpreter)
 
 ######

llvm/cmake/modules/LLVMConfig.cmake.in

 set(LLVM_ENABLE_DIA_SDK @LLVM_ENABLE_DIA_SDK@)
 
 set(LLVM_NATIVE_ARCH @LLVM_NATIVE_ARCH@)
 
 set(LLVM_ENABLE_PIC @LLVM_ENABLE_PIC@)
 
 set(LLVM_BUILD_32_BITS @LLVM_BUILD_32_BITS@)
 
-set(LLVM_ENABLE_NEW_PASS_MANAGER @LLVM_ENABLE_NEW_PASS_MANAGER@)
-
 if (NOT "@LLVM_PTHREAD_LIB@" STREQUAL "")
   set(LLVM_PTHREAD_LIB "@LLVM_PTHREAD_LIB@")
 endif()
 
 set(LLVM_ENABLE_PLUGINS @LLVM_ENABLE_PLUGINS@)
 set(LLVM_EXPORT_SYMBOLS_FOR_PLUGINS @LLVM_EXPORT_SYMBOLS_FOR_PLUGINS@)
 set(LLVM_PLUGIN_EXT @LLVM_PLUGIN_EXT@)
 

llvm/docs/NewPassManager.rst

 ==========================================
 
 LLVM currently contains two pass managers, the legacy PM and the new PM. The
 optimization pipeline (aka the middle-end) works with both the legacy PM and
 the new PM, whereas the backend target-dependent code generation only works
 with the legacy PM.
 
 For the optimization pipeline, the new PM is the default PM. The legacy PM is
-available for the optimization pipeline either by setting the CMake flag
-``-DLLVM_ENABLE_NEW_PASS_MANAGER=OFF`` when building LLVM, or by
-various compiler/linker flags, e.g. ``-flegacy-pass-manager`` for ``clang``.
+available for the optimization pipeline by setting various compiler/linker
+flags, e.g. ``-flegacy-pass-manager`` for ``clang``.
 
 There will be efforts to deprecate and remove the legacy PM for the
 optimization pipeline in the future.
 
 Some IR passes are considered part of the backend codegen pipeline even if
 they are LLVM IR passes (whereas all MIR passes are codegen passes). This
 includes anything added via ``TargetPassConfig`` hooks, e.g.
 ``TargetPassConfig::addCodeGenPrepare()``. As mentioned before, passes added
 in ``TargetMachine::adjustPassManager()`` are part of the optimization
 pipeline, and should have a corresponding line in
 ``TargetMachine::registerPassBuilderCallbacks()``.
 
 Currently there are efforts to make the codegen pipeline work with the new
 PM.

llvm/include/llvm/Config/llvm-config.h.cmake

 #cmakedefine01 LLVM_ENABLE_ZLIB
 
 /* Define if LLVM was built with a dependency to the libtensorflow dynamic library */
 #cmakedefine LLVM_HAVE_TF_API
 
 /* Define to 1 if you have the <sysexits.h> header file. */
 #cmakedefine HAVE_SYSEXITS_H ${HAVE_SYSEXITS_H}
 
-/* Define to 1 to enable the experimental new pass manager by default */
-#cmakedefine01 LLVM_ENABLE_NEW_PASS_MANAGER
-
 /* Define if the xar_open() function is supported on this platform. */
 #cmakedefine LLVM_HAVE_LIBXAR ${LLVM_HAVE_LIBXAR}
 
 /* Define if building libLLVM shared library */
 #cmakedefine LLVM_BUILD_LLVM_DYLIB
 
 /* Define if building LLVM with BUILD_SHARED_LIBS */
 #cmakedefine LLVM_BUILD_SHARED_LIBS

llvm/include/llvm/LTO/Config.h

struct Config {
   Optional<Reloc::Model> RelocModel = Reloc::PIC_;
   Optional<CodeModel::Model> CodeModel = None;
   CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
   CodeGenFileType CGFileType = CGFT_ObjectFile;
   unsigned OptLevel = 2;
   bool DisableVerify = false;
 
   /// Use the new pass manager
-  bool UseNewPM = LLVM_ENABLE_NEW_PASS_MANAGER;
+  bool UseNewPM = true;
 
   /// Use the standard optimization pipeline.
   bool UseDefaultPipeline = false;
 
   /// Flag to indicate that the optimizer should not assume builtins are present
   /// on the target.
   bool Freestanding = false;
 

llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h

private:
   /// on the target.
   bool Freestanding = false;
 
   /// IR Optimization Level [0-3].
   unsigned OptLevel = 3;
 
   /// Flag to indicate whether the new pass manager should be used for IR
   /// optimizations.
-  bool UseNewPM = LLVM_ENABLE_NEW_PASS_MANAGER;
+  bool UseNewPM = true;
 
   /// Flag to indicate whether debug output should be enabled for the new pass
   /// manager.
   bool DebugPassManager = false;
 };
 }
 #endif

llvm/tools/gold/gold-plugin.cpp

#endif
   static std::string cache_policy;
   // Additional options to pass into the code generator.
   // Note: This array will contain all plugin options which are not claimed
   // as plugin exclusive to pass to the code generator.
   static std::vector<const char *> extra;
   // Sample profile file path
   static std::string sample_profile;
   // New pass manager
-  static bool new_pass_manager = LLVM_ENABLE_NEW_PASS_MANAGER;
+  static bool new_pass_manager = true;
   // Debug new pass manager
   static bool debug_pass_manager = false;
   // Directory to store the .dwo files.
   static std::string dwo_dir;
   /// Statistics output filename.
   static std::string stats_file;
   // Asserts that LTO link has whole program visibility
   static bool whole_program_visibility = false;

llvm/tools/llvm-lto/llvm-lto.cpp

static cl::opt<bool> CheckHasObjC(
     cl::desc("Only check if the module has objective-C defined in it"),
     cl::cat(LTOCategory));
 
 static cl::opt<bool> PrintMachOCPUOnly(
     "print-macho-cpu-only", cl::init(false),
     cl::desc("Instead of running LTO, print the mach-o cpu in each IR file"),
     cl::cat(LTOCategory));
 
 static cl::opt<bool> UseNewPM(
     "use-new-pm", cl::desc("Run LTO passes using the new pass manager"),
-    cl::init(LLVM_ENABLE_NEW_PASS_MANAGER), cl::Hidden, cl::cat(LTOCategory));
+    cl::init(true), cl::Hidden, cl::cat(LTOCategory));
 
 static cl::opt<bool>
     DebugPassManager("debug-pass-manager", cl::init(false), cl::Hidden,
                      cl::desc("Print pass management debugging information"),
                      cl::cat(LTOCategory));
 
 namespace {
 

llvm/tools/llvm-lto2/llvm-lto2.cpp

 static cl::opt<bool>
     RunCSIRInstr("lto-cspgo-gen",
                  cl::desc("Run PGO context sensitive IR instrumentation"),
                  cl::init(false), cl::Hidden);
 
 static cl::opt<bool>
     UseNewPM("use-new-pm",
              cl::desc("Run LTO passes using the new pass manager"),
-             cl::init(LLVM_ENABLE_NEW_PASS_MANAGER), cl::Hidden);
+             cl::init(true), cl::Hidden);
 
 static cl::opt<bool>
     DebugPassManager("debug-pass-manager", cl::init(false), cl::Hidden,
                      cl::desc("Print pass management debugging information"));
 
 static cl::opt<std::string>
     StatsFile("stats-file", cl::desc("Filename to write statistics to"));
 

llvm/tools/opt/opt.cpp

 static cl::list<const PassInfo *, bool, PassNameParser> PassList(cl::desc(
     "Optimizations available (use '-passes=' for the new pass manager)"));
 
 static cl::opt<bool> EnableNewPassManager(
     "enable-new-pm",
     cl::desc("Enable the new pass manager, translating "
              "'opt -foo' to 'opt -passes=foo'. This is strictly for the new PM "
              "migration, use '-passes=' when possible."),
-    cl::init(LLVM_ENABLE_NEW_PASS_MANAGER));
+    cl::init(true));
 
 // This flag specifies a textual description of the optimization pass pipeline
 // to run over the module. This flag switches opt to use the new pass manager
 // infrastructure, completely disabling all of the flags specific to the old
 // pass management.
 static cl::opt<std::string> PassPipeline(
     "passes",
     cl::desc(

llvm/utils/gn/secondary/clang/test/BUILD.gn

extra_values = [
     # OS is macOS. Since the GN build currently never uses LLVM_USE_SANITIZER,
     # this is never read.  If it's ever needed,
     # utils/gn/build/toolchain/BUILD.gn should get the compiler from a variable
     # that's also read here -- but that should happen after multi-toolchain
     # builds exist, to make sure it's a toolchain var.
     "CMAKE_CXX_COMPILER=c++",
     "CMAKE_C_COMPILER=cc",
     "ENABLE_BACKTRACES=1",
-    "LLVM_ENABLE_NEW_PASS_MANAGER=1",
     "LLVM_EXTERNAL_LIT=",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
     "LLVM_LIT_TOOLS_DIR=",  # Intentionally empty, matches cmake build.
     "LLVM_USE_SANITIZER=",
     "Python3_EXECUTABLE=$python_path",
     "USE_Z3_SOLVER=",
   ]
 

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

 write_cmake_config("llvm-config") {
   input = "llvm-config.h.cmake"
   output = "$target_gen_dir/llvm-config.h"
   values = [
     "LLVM_BUILD_LLVM_DYLIB=",
     "LLVM_BUILD_SHARED_LIBS=",
     "LLVM_DEFAULT_TARGET_TRIPLE=$llvm_target_triple",
     "LLVM_ENABLE_DUMP=",
-    "LLVM_ENABLE_NEW_PASS_MANAGER=1",
     "LLVM_FORCE_ENABLE_STATS=",
     "LLVM_FORCE_USE_OLD_TOOLCHAIN=",
     "LLVM_HAS_ATOMICS=1",
     "LLVM_HAVE_TF_API=",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
     "LLVM_NATIVE_ARCH=$native_target",
     "LLVM_NATIVE_ASMPARSER=1",
     "LLVM_NATIVE_ASMPRINTER=1",

utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/llvm-config.h

 /* #undef LLVM_HAVE_TF_API */
 
 /* Define if LLVM was built with a dependency to the tensorflow compiler */
 /* #undef LLVM_HAVE_TF_AOT */
 
 /* Define to 1 if you have the <sysexits.h> header file. */
 /* HAVE_SYSEXITS_H defined in Bazel */
 
-/* Define to 1 to enable the experimental new pass manager by default */
-#define LLVM_ENABLE_NEW_PASS_MANAGER 0
-
 /* Define if the xar_open() function is supported this platform. */
 /* #undef HAVE_LIBXAR */
 
 /* Define if building libLLVM shared library */
 /* #undef LLVM_BUILD_LLVM_DYLIB */
 
 /* Define if building LLVM with BUILD_SHARED_LIBS */
 /* #undef LLVM_BUILD_SHARED_LIBS */

utils/bazel/llvm_configs/llvm-config.h.cmake

 #cmakedefine01 LLVM_ENABLE_ZLIB
 
 /* Define if LLVM was built with a dependency to the libtensorflow dynamic library */
 #cmakedefine LLVM_HAVE_TF_API
 
 /* Define to 1 if you have the <sysexits.h> header file. */
 #cmakedefine HAVE_SYSEXITS_H ${HAVE_SYSEXITS_H}
 
-/* Define to 1 to enable the experimental new pass manager by default */
-#cmakedefine01 LLVM_ENABLE_NEW_PASS_MANAGER
-
 /* Define if the xar_open() function is supported on this platform. */
 #cmakedefine LLVM_HAVE_LIBXAR ${LLVM_HAVE_LIBXAR}
 
 /* Define if building libLLVM shared library */
 #cmakedefine LLVM_BUILD_LLVM_DYLIB
 
 /* Define if building LLVM with BUILD_SHARED_LIBS */
 #cmakedefine LLVM_BUILD_SHARED_LIBS