[LTO][wasm][NewPM] Allow using new pass manager for wasm LTO

[aeubanks]

whoops, default to false to match current behavior

[sbc100]

Do all these change essentially match the ELF linker? A brief look makes me thing they do.

[aeubanks]

In D92150#2426392, @sbc100 wrote:

Do all these change essentially match the ELF linker? A brief look makes me thing they do.

yup that's the idea

lld/test/wasm/lto/new-pass-manager.ll

+; RUN: llvm-as -o %t.bc %s
+; RUN: wasm-ld --lto-new-pass-manager --lto-debug-pass-manager -o /dev/null %t.bc 2>&1 | FileCheck %s
+; RUN: wasm-ld --lto-new-pass-manager --lto-debug-pass-manager --lto-no-new-pass-manager -o /dev/null %t.bc 2>&1 | FileCheck %s --allow-empty --check-prefix=LPM
+
+; CHECK: Starting llvm::Module pass manager run
+; CHECK: Finished llvm::Module pass manager run
+; LPM-NOT: Starting llvm::Module pass manager run
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+define void @_start() local_unnamed_addr {
+entry:
+  ret void
+}

lld/wasm/Config.h

struct Configuration {
   uint64_t globalBase;
   uint64_t initialMemory;
   uint64_t maxMemory;
   uint64_t zStackSize;
   unsigned ltoPartitions;
   unsigned ltoo;
   unsigned optimize;
   llvm::StringRef thinLTOJobs;
+  bool ltoNewPassManager;
+  bool ltoDebugPassManager;
   UnresolvedPolicy unresolvedSymbols;
 
   llvm::StringRef entry;
   llvm::StringRef mapFile;
   llvm::StringRef outputFile;
   llvm::StringRef thinLTOCacheDir;
 
   llvm::StringSet<> allowUndefinedSymbols;

lld/wasm/Driver.cpp

static void readConfigs(opt::InputArgList &args) {
   config->growableTable = args.hasArg(OPT_growable_table);
   errorHandler().fatalWarnings =
       args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
   config->importMemory = args.hasArg(OPT_import_memory);
   config->sharedMemory = args.hasArg(OPT_shared_memory);
   config->importTable = args.hasArg(OPT_import_table);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
+  config->ltoNewPassManager = args.hasFlag(OPT_lto_new_pass_manager,
+                                           OPT_lto_no_new_pass_manager, false);
+  config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->mapFile = args.getLastArgValue(OPT_Map);
   config->optimize = args::getInteger(args, OPT_O, 0);
   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 =
       args.hasFlag(OPT_merge_data_segments, OPT_no_merge_data_segments,

lld/wasm/LTO.cpp

static std::unique_ptr<lto::LTO> createLTO() {
   c.Options.FunctionSections = true;
   c.Options.DataSections = true;
 
   c.DisableVerify = config->disableVerify;
   c.DiagHandler = diagnosticHandler;
   c.OptLevel = config->ltoo;
   c.MAttrs = getMAttrs();
   c.CGOptLevel = args::getCGOptLevel(config->ltoo);
+  c.UseNewPM = config->ltoNewPassManager;
+  c.DebugPassManager = config->ltoDebugPassManager;
 
   if (config->relocatable)
     c.RelocModel = None;
   else if (config->isPic)
     c.RelocModel = Reloc::PIC_;
   else
     c.RelocModel = Reloc::Static;
 

lld/wasm/Options.td

def lto_partitions: J<"lto-partitions=">,
   HelpText<"Number of LTO codegen partitions">;
 def disable_verify: F<"disable-verify">;
 def save_temps: F<"save-temps">;
 def thinlto_cache_dir: J<"thinlto-cache-dir=">,
   HelpText<"Path to ThinLTO cached object file directory">;
 defm thinlto_cache_policy: Eq<"thinlto-cache-policy", "Pruning policy for the ThinLTO cache">;
 def thinlto_jobs: J<"thinlto-jobs=">,
   HelpText<"Number of ThinLTO jobs. Default to --threads=">;
+def lto_new_pass_manager: F<"lto-new-pass-manager">,
+  HelpText<"Use new pass manager">;
+def lto_no_new_pass_manager: F<"lto-no-new-pass-manager">,
+  HelpText<"Use legacy pass manager">;
+def lto_debug_pass_manager: F<"lto-debug-pass-manager">,
+  HelpText<"Debug new pass manager">;
 
 // Experimental PIC mode.
 def experimental_pic: F<"experimental-pic">,
   HelpText<"Enable Experimental PIC">;