[lld] add context-sensitive PGO options for COFF.

Add lld CSPGO (Contex-Sensitive PGO) options for COFF target.

Reference the ELF options from https://reviews.llvm.org/D56675

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D98763

Author: yolanda15

lld/COFF/Config.h

@@ -215,6 +215,12 @@ struct Configuration {
   // Used for /lto-obj-path:
   llvm::StringRef ltoObjPath;
 
+  // Used for /lto-cs-profile-generate:
+  bool ltoCSProfileGenerate = false;
+
+  // Used for /lto-cs-profile-path
+  llvm::StringRef ltoCSProfileFile;
+
   // Used for /call-graph-ordering-file:
   llvm::MapVector<std::pair<const SectionChunk *, const SectionChunk *>,
                   uint64_t>

lld/COFF/Driver.cpp

@@ -1712,6 +1712,8 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   config->thinLTOObjectSuffixReplace =
       getOldNewOptions(args, OPT_thinlto_object_suffix_replace);
   config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path);
+  config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
+  config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   // Handle miscellaneous boolean flags.
   config->allowBind = args.hasFlag(OPT_allowbind, OPT_allowbind_no, true);
   config->allowIsolation =

lld/COFF/LTO.cpp

@@ -84,6 +84,8 @@ static lto::Config createConfig() {
   c.AlwaysEmitRegularLTOObj = !config->ltoObjPath.empty();
   c.UseNewPM = config->ltoNewPassManager;
   c.DebugPassManager = config->ltoDebugPassManager;
+  c.CSIRProfile = std::string(config->ltoCSProfileFile);
+  c.RunCSIRInstr = config->ltoCSProfileGenerate;
 
   if (config->saveTemps)
     checkError(c.addSaveTemps(std::string(config->outputFile) + ".",

lld/COFF/Options.td

@@ -239,6 +239,10 @@ def thinlto_prefix_replace: P<
 def lto_obj_path : P<
     "lto-obj-path",
     "output native object for merged LTO unit to this path">;
+def lto_cs_profile_generate: F<"lto-cs-profile-generate">,
+    HelpText<"Perform context sensitive PGO instrumentation">;
+def lto_cs_profile_file : P<"lto-cs-profile-file",
+    "Context sensitive profile file path">;
 def dash_dash_version : Flag<["--"], "version">,
   HelpText<"Display the version number and exit">;
 def threads