[llvm-gsymutil] Add gsymuil to llvm driver build

[phosek]

LGTM % the subject says "gsymuil" instead of "gsymutil'.

[abrachet]

In D149283#4304423, @phosek wrote:

LGTM % the subject says "gsymuil" instead of "gsymutil'.

Done in commit

llvm/tools/llvm-gsymutil/CMakeLists.txt

 tablegen(LLVM Opts.inc -gen-opt-parser-defs)
 add_public_tablegen_target(GSYMUtilOptsTableGen)
 
 add_llvm_tool(llvm-gsymutil
   llvm-gsymutil.cpp
 
   DEPENDS
   GSYMUtilOptsTableGen
+
+  GENERATE_DRIVER
   )

llvm/tools/llvm-gsymutil/llvm-gsymutil.cpp

 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/MachOUniversal.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Triple.h"
if (Verbose)
       OS << "\nLookupResult for " << HEX64(Addr) << ":\n";
     OS << HEX64(Addr) << ": ";
     logAllUnhandledErrors(Result.takeError(), OS, "error: ");
   }
   if (Verbose)
     OS << "\n";
 }
 
-int main(int argc, char **argv) {
+int llvm_gsymutil_main(int argc, char **argv, const llvm::ToolContext &) {
   // Print a stack trace if we signal out.
   sys::PrintStackTraceOnErrorSignal(argv[0]);
   PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
 
   llvm::InitializeAllTargets();
 
   parseArgs(argc, argv);

llvm/utils/gn/secondary/llvm/tools/llvm-gsymutil/BUILD.gn

 import("//llvm/utils/TableGen/tablegen.gni")
+import("//llvm/utils/gn/build/driver_executable.gni")
 
 tablegen("Opts") {
   visibility = [ ":llvm-gsymutil" ]
   args = [ "-gen-opt-parser-defs" ]
 }
 
-executable("llvm-gsymutil") {
+driver_executable("llvm-gsymutil") {
   deps = [
     ":Opts",
     "//llvm/lib/DebugInfo/DWARF",
     "//llvm/lib/DebugInfo/GSYM",
     "//llvm/lib/Object",
     "//llvm/lib/Option",
     "//llvm/lib/Support",
     "//llvm/lib/Target",
     "//llvm/lib/Target:TargetsToBuild",
     "//llvm/lib/TargetParser",
   ]
   sources = [ "llvm-gsymutil.cpp" ]
 }

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

tbl_outs = [(
         "-gen-opt-parser-defs",
         "tools/llvm-gsymutil/Opts.inc",
     )],
     tblgen = ":llvm-tblgen",
     td_file = "tools/llvm-gsymutil/Opts.td",
     td_srcs = ["include/llvm/Option/OptParser.td"],
 )
 
+expand_template(
+    name = "gsymutil_main",
+    out = "llvm-gsymutil-driver.cpp",
+    substitutions = {
+        "@TOOL_NAME@": "llvm_gsymutil",
+    },
+    template = "cmake/modules/llvm-driver-template.cpp.in",
+)
+
 cc_binary(
     name = "llvm-gsymutil",
     srcs = glob([
         "tools/llvm-gsymutil/*.cpp",
         "tools/llvm-gsymutil/*.h",
-    ]),
+    ]) + ["llvm-gsymutil-driver.cpp"],
     copts = llvm_copts,
     stamp = 0,
     deps = [
         ":AllTargetsCodeGens",
         ":DebugInfo",
         ":DebugInfoDWARF",
         ":DebugInfoGSYM",
         ":GSYMUtilOptionsTableGen",