[lld-link] Add /lto-newpm-passes & /load-pass-plugin to CLI

[cursey]

Summary

This change adds /lto-newpm-passes and /load-pass-plugin command line arguments to lld-link. These are basically exactly the same arguments lld already has (--lto-newpm-passes and --load-pass-plugin) to enable loading custom LTO passes.

lld/COFF/Config.h

struct Configuration {
   bool repro = false;
   bool swaprunCD = false;
   bool swaprunNet = false;
   bool thinLTOEmitImportsFiles;
   bool thinLTOIndexOnly;
   bool autoImport = false;
   bool pseudoRelocs = false;
   bool stdcallFixup = false;
+
+  llvm::StringRef ltoNewPmPasses;
+  llvm::SmallVector<llvm::StringRef, 0> passPlugins;
 };
 
 extern std::unique_ptr<Configuration> config;
 
 } // namespace lld::coff
 
 #endif

lld/COFF/Driver.cpp

void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   config->pseudoRelocs = args.hasFlag(
       OPT_runtime_pseudo_reloc, OPT_runtime_pseudo_reloc_no, config->mingw);
   config->callGraphProfileSort = args.hasFlag(
       OPT_call_graph_profile_sort, OPT_call_graph_profile_sort_no, true);
   config->stdcallFixup =
       args.hasFlag(OPT_stdcall_fixup, OPT_stdcall_fixup_no, config->mingw);
   config->warnStdcallFixup = !args.hasArg(OPT_stdcall_fixup);
 
+  config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
+  config->passPlugins = args::getStrings(args, OPT_load_pass_plugins);
+
   // Don't warn about long section names, such as .debug_info, for mingw or
   // when -debug:dwarf is requested.
   if (config->mingw || config->debugDwarf)
     config->warnLongSectionNames = false;
 
   if (config->incremental && args.hasArg(OPT_profile)) {
     warn("ignoring '/incremental' due to '/profile' specification");
     config->incremental = false;

lld/COFF/LTO.cpp

#endif
   c.CPU = getCPUStr();
   c.MAttrs = getMAttrs();
   c.CGOptLevel = args::getCGOptLevel(config->ltoo);
   c.AlwaysEmitRegularLTOObj = !config->ltoObjPath.empty();
   c.DebugPassManager = config->ltoDebugPassManager;
   c.CSIRProfile = std::string(config->ltoCSProfileFile);
   c.RunCSIRInstr = config->ltoCSProfileGenerate;
   c.PGOWarnMismatch = config->ltoPGOWarnMismatch;
+  c.OptPipeline = std::string(config->ltoNewPmPasses);
+
+  for (StringRef pluginFn : config->passPlugins)
+    c.PassPlugins.push_back(std::string(pluginFn));
 
   if (config->saveTemps)
     checkError(c.addSaveTemps(std::string(config->outputFile) + ".",
                               /*UseInputModulePath*/ true));
   return c;
 }
 
 BitcodeCompiler::BitcodeCompiler() {

lld/COFF/Options.td

 def print_symbol_order: P<
     "print-symbol-order",
     "Print a symbol order specified by /call-graph-ordering-file and "
     "/call-graph-profile-sort into the specified file">;
 def wrap : P_priv<"wrap">;
 
 def vfsoverlay : P<"vfsoverlay", "Path to a vfsoverlay yaml file to optionally look for /defaultlib's in">;
 
+def lto_newpm_passes: P<"lto-newpm-passes", "Passes to run during LTO">;
+def load_pass_plugins: P<"load-pass-plugin", "Load passes from plugin library">;
+
 // Flags for debugging
 def lldmap : F<"lldmap">;
 def lldmap_file : P_priv<"lldmap">;
 def map : F<"map">;
 def map_file : P_priv<"map">;
 def map_info : P<"mapinfo", "Include the specified information in a map file">;
 def show_timing : F<"time">;
 def summary : F<"summary">;