--- a/lld/ELF/Driver.cpp	Mon May 25 11:50:15 2020 +0900
+++ b/lld/ELF/Driver.cpp	Mon May 25 11:55:54 2020 +0900
@@ -43,7 +43,6 @@
 #include "lld/Common/Memory.h"
 #include "lld/Common/Strings.h"
 #include "lld/Common/TargetOptionsCommandFlags.h"
-#include "lld/Common/Threads.h"
 #include "lld/Common/Version.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringExtras.h"
@@ -53,6 +52,7 @@
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/GlobPattern.h"
 #include "llvm/Support/LEB128.h"
+#include "llvm/Support/Parallel.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
@@ -66,18 +66,17 @@
 using namespace llvm::object;
 using namespace llvm::sys;
 using namespace llvm::support;
+using namespace lld;
+using namespace lld::elf;
 
-namespace lld {
-namespace elf {
-
-Configuration *config;
-LinkerDriver *driver;
+Configuration *elf::config;
+LinkerDriver *elf::driver;
 
 static void setConfigs(opt::InputArgList &args);
 static void readConfigs(opt::InputArgList &args);
 
-bool link(ArrayRef<const char *> args, bool canExitEarly, raw_ostream &stdoutOS,
-          raw_ostream &stderrOS) {
+bool elf::link(ArrayRef<const char *> args, bool canExitEarly,
+               raw_ostream &stdoutOS, raw_ostream &stderrOS) {
   lld::stdoutOS = &stdoutOS;
   lld::stderrOS = &stderrOS;
 
@@ -90,10 +89,13 @@
 
   inputSections.clear();
   outputSections.clear();
+  archiveFiles.clear();
   binaryFiles.clear();
   bitcodeFiles.clear();
+  lazyObjFiles.clear();
   objectFiles.clear();
   sharedFiles.clear();
+  backwardReferences.clear();
 
   config = make<Configuration>();
   driver = make<LinkerDriver>();
@@ -148,6 +150,7 @@
           .Cases("elf_amd64", "elf_x86_64", {ELF64LEKind, EM_X86_64})
           .Case("elf_i386", {ELF32LEKind, EM_386})
           .Case("elf_iamcu", {ELF32LEKind, EM_IAMCU})
+          .Case("elf64_sparc", {ELF64BEKind, EM_SPARCV9})
           .Default({ELFNoneKind, EM_NONE});
 
   if (ret.first == ELFNoneKind)
@@ -351,9 +354,9 @@
     error("-z force-ibt may not be used with -z retpolineplt");
 
   if (config->emachine != EM_AARCH64) {
-    if (config->pacPlt)
+    if (config->zPacPlt)
       error("-z pac-plt only supported on AArch64");
-    if (config->forceBTI)
+    if (config->zForceBti)
       error("-z force-bti only supported on AArch64");
   }
 }
@@ -530,17 +533,14 @@
   }
 
   if (config->timeTraceEnabled) {
-    // Write the result of the time trace profiler.
-    std::string path = args.getLastArgValue(OPT_time_trace_file_eq).str();
-    if (path.empty())
-      path = (config->outputFile + ".time-trace").str();
-    std::error_code ec;
-    raw_fd_ostream os(path, ec, sys::fs::OF_Text);
-    if (ec) {
-      error("cannot open " + path + ": " + ec.message());
+    if (auto E = timeTraceProfilerWrite(args.getLastArgValue(OPT_time_trace_file_eq).str(),
+                                        config->outputFile)) {
+      handleAllErrors(std::move(E), [&](const StringError &SE) {
+        error(SE.getMessage());
+      });
       return;
     }
-    timeTraceProfilerWrite(os);
+
     timeTraceProfilerCleanup();
   }
 }
@@ -610,9 +610,6 @@
 }
 
 static DiscardPolicy getDiscard(opt::InputArgList &args) {
-  if (args.hasArg(OPT_relocatable))
-    return DiscardPolicy::None;
-
   auto *arg =
       args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
   if (!arg)
@@ -863,7 +860,6 @@
       args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
   errorHandler().vsDiagnostics =
       args.hasArg(OPT_visual_studio_diagnostics_format, false);
-  threadsEnabled = args.hasFlag(OPT_threads, OPT_no_threads, true);
 
   config->allowMultipleDefinition =
       args.hasFlag(OPT_allow_multiple_definition,
@@ -882,6 +878,8 @@
   config->cref = args.hasFlag(OPT_cref, OPT_no_cref, false);
   config->defineCommon = args.hasFlag(OPT_define_common, OPT_no_define_common,
                                       !args.hasArg(OPT_relocatable));
+  config->optimizeBBJumps =
+      args.hasFlag(OPT_optimize_bb_jumps, OPT_no_optimize_bb_jumps, false);
   config->demangle = args.hasFlag(OPT_demangle, OPT_no_demangle, true);
   config->dependentLibraries = args.hasFlag(OPT_dependent_libraries, OPT_no_dependent_libraries, true);
   config->disableVerify = args.hasArg(OPT_disable_verify);
@@ -907,7 +905,6 @@
                                      !args.hasArg(OPT_relocatable);
   config->fixCortexA8 =
       args.hasArg(OPT_fix_cortex_a8) && !args.hasArg(OPT_relocatable);
-  config->forceBTI = hasZOption(args, "force-bti");
   config->gcSections = args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
   config->gnuUnique = args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
   config->gdbIndex = args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
@@ -921,6 +918,7 @@
   config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
   config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
+  config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
   config->ltoNewPassManager = args.hasArg(OPT_lto_new_pass_manager);
   config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
   config->ltoWholeProgramVisibility =
@@ -929,6 +927,11 @@
   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);
+  config->ltoBasicBlockSections =
+      args.getLastArgValue(OPT_lto_basicblock_sections);
+  config->ltoUniqueBBSectionNames =
+      args.hasFlag(OPT_lto_unique_bb_section_names,
+                   OPT_no_lto_unique_bb_section_names, false);
   config->mapFile = args.getLastArgValue(OPT_Map);
   config->mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
   config->mergeArmExidx =
@@ -947,21 +950,23 @@
   config->optimize = args::getInteger(args, OPT_O, 1);
   config->orphanHandling = getOrphanHandling(args);
   config->outputFile = args.getLastArgValue(OPT_o);
-  config->pacPlt = hasZOption(args, "pac-plt");
   config->pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
   config->printIcfSections =
       args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
   config->printGcSections =
       args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
+  config->printArchiveStats = args.getLastArgValue(OPT_print_archive_stats);
   config->printSymbolOrder =
       args.getLastArgValue(OPT_print_symbol_order);
   config->rpath = getRpath(args);
   config->relocatable = args.hasArg(OPT_relocatable);
   config->saveTemps = args.hasArg(OPT_save_temps);
+  if (args.hasArg(OPT_shuffle_sections))
+    config->shuffleSectionSeed = args::getInteger(args, OPT_shuffle_sections, 0);
   config->searchPaths = args::getStrings(args, OPT_library_path);
   config->sectionStartMap = getSectionStartMap(args);
   config->shared = args.hasArg(OPT_shared);
-  config->singleRoRx = args.hasArg(OPT_no_rosegment);
+  config->singleRoRx = !args.hasFlag(OPT_rosegment, OPT_no_rosegment, true);
   config->soName = args.getLastArgValue(OPT_soname);
   config->sortSection = getSortSection(args);
   config->splitStackAdjustSize = args::getInteger(args, OPT_split_stack_adjust_size, 16384);
@@ -977,7 +982,6 @@
   config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
                              args.hasArg(OPT_thinlto_index_only_eq);
   config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
-  config->thinLTOJobs = args::getInteger(args, OPT_thinlto_jobs, -1u);
   config->thinLTOObjectSuffixReplace =
       getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
   config->thinLTOPrefixReplace =
@@ -989,6 +993,7 @@
   config->undefined = args::getStrings(args, OPT_undefined);
   config->undefinedVersion =
       args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, true);
+  config->unique = args.hasArg(OPT_unique);
   config->useAndroidRelrTags = args.hasFlag(
       OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
   config->unresolvedSymbols = getUnresolvedSymbolPolicy(args);
@@ -1001,6 +1006,7 @@
       args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
   config->zCombreloc = getZFlag(args, "combreloc", "nocombreloc", true);
   config->zCopyreloc = getZFlag(args, "copyreloc", "nocopyreloc", true);
+  config->zForceBti = hasZOption(args, "force-bti");
   config->zForceIbt = hasZOption(args, "force-ibt");
   config->zGlobal = hasZOption(args, "global");
   config->zGnustack = getZGnuStack(args);
@@ -1015,6 +1021,7 @@
   config->zNodlopen = hasZOption(args, "nodlopen");
   config->zNow = getZFlag(args, "now", "lazy", false);
   config->zOrigin = hasZOption(args, "origin");
+  config->zPacPlt = hasZOption(args, "pac-plt");
   config->zRelro = getZFlag(args, "relro", "norelro", true);
   config->zRetpolineplt = hasZOption(args, "retpolineplt");
   config->zRodynamic = hasZOption(args, "rodynamic");
@@ -1029,19 +1036,41 @@
     parseClangOption(saver.save("-mcpu=" + StringRef(arg->getValue())),
                      arg->getSpelling());
 
-  for (auto *arg : args.filtered(OPT_plugin_opt))
-    parseClangOption(arg->getValue(), arg->getSpelling());
+  for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq_minus))
+    parseClangOption(std::string("-") + arg->getValue(), arg->getSpelling());
+
+  // GCC collect2 passes -plugin-opt=path/to/lto-wrapper with an absolute or
+  // relative path. Just ignore. If not ended with "lto-wrapper", consider it an
+  // unsupported LLVMgold.so option and error.
+  for (opt::Arg *arg : args.filtered(OPT_plugin_opt_eq))
+    if (!StringRef(arg->getValue()).endswith("lto-wrapper"))
+      error(arg->getSpelling() + ": unknown plugin option '" + arg->getValue() +
+            "'");
 
   // Parse -mllvm options.
   for (auto *arg : args.filtered(OPT_mllvm))
     parseClangOption(arg->getValue(), arg->getSpelling());
 
+  // --threads= takes a positive integer and provides the default value for
+  // --thinlto-jobs=.
+  if (auto *arg = args.getLastArg(OPT_threads)) {
+    StringRef v(arg->getValue());
+    unsigned threads = 0;
+    if (!llvm::to_integer(v, threads, 0) || threads == 0)
+      error(arg->getSpelling() + ": expected a positive integer, but got '" +
+            arg->getValue() + "'");
+    parallel::strategy = hardware_concurrency(threads);
+    config->thinLTOJobs = v;
+  }
+  if (auto *arg = args.getLastArg(OPT_thinlto_jobs))
+    config->thinLTOJobs = arg->getValue();
+
   if (config->ltoo > 3)
     error("invalid optimization level for LTO: " + Twine(config->ltoo));
   if (config->ltoPartitions == 0)
     error("--lto-partitions: number of threads must be > 0");
-  if (config->thinLTOJobs == 0)
-    error("--thinlto-jobs: number of threads must be > 0");
+  if (!get_threadpool_strategy(config->thinLTOJobs))
+    error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
 
   if (config->splitStackAdjustSize < 0)
     error("--split-stack-adjust-size: size must be >= 0");
@@ -1119,6 +1148,14 @@
             {s, /*isExternCpp=*/false, /*hasWildcard=*/false});
   }
 
+  for (opt::Arg *arg : args.filtered(OPT_warn_backrefs_exclude)) {
+    StringRef pattern(arg->getValue());
+    if (Expected<GlobPattern> pat = GlobPattern::create(pattern))
+      config->warnBackrefsExclude.push_back(std::move(*pat));
+    else
+      error(arg->getSpelling() + ": " + toString(pat.takeError()));
+  }
+
   // Parses -dynamic-list and -export-dynamic-symbol. They make some
   // symbols private. Note that -export-dynamic takes precedence over them
   // as it says all symbols should be exported.
@@ -1428,6 +1465,10 @@
   // eliminate it. Mark the symbol as "used" to prevent it.
   sym->isUsedInRegularObj = true;
 
+  // GNU linkers allow -u foo -ldef -lref. We should not treat it as a backward
+  // reference.
+  backwardReferences.erase(sym);
+
   if (sym->isLazy())
     sym->fetch();
 }
@@ -1735,8 +1776,9 @@
   uint32_t ret = -1;
   for (InputFile *f : objectFiles) {
     uint32_t features = cast<ObjFile<ELFT>>(f)->andFeatures;
-    if (config->forceBTI && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
-      warn(toString(f) + ": -z force-bti: file does not have BTI property");
+    if (config->zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
+      warn(toString(f) + ": -z force-bti: file does not have "
+                         "GNU_PROPERTY_AARCH64_FEATURE_1_BTI property");
       features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
     } else if (config->zForceIbt &&
                !(features & GNU_PROPERTY_X86_FEATURE_1_IBT)) {
@@ -1744,13 +1786,14 @@
                          "GNU_PROPERTY_X86_FEATURE_1_IBT property");
       features |= GNU_PROPERTY_X86_FEATURE_1_IBT;
     }
+    if (config->zPacPlt && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) {
+      warn(toString(f) + ": -z pac-plt: file does not have "
+                         "GNU_PROPERTY_AARCH64_FEATURE_1_PAC property");
+      features |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
+    }
     ret &= features;
   }
 
-  // Force enable pointer authentication Plt, we don't warn in this case as
-  // this does not require support in the object for correctness.
-  if (config->pacPlt)
-    ret |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
   // Force enable Shadow Stack.
   if (config->zShstk)
     ret |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
@@ -1900,19 +1943,19 @@
   // With this the symbol table should be complete. After this, no new names
   // except a few linker-synthesized ones will be added to the symbol table.
   compileBitcodeFiles<ELFT>();
+
+  // Symbol resolution finished. Report backward reference problems.
+  reportBackrefs();
   if (errorCount())
     return;
 
   // If -thinlto-index-only is given, we should create only "index
   // files" and not object files. Index file creation is already done
   // in addCombinedLTOObject, so we are done if that's the case.
-  if (config->thinLTOIndexOnly)
-    return;
-
-  // Likewise, --plugin-opt=emit-llvm is an option to make LTO create
-  // an output file in bitcode and exit, so that you can just get a
-  // combined bitcode file.
-  if (config->emitLLVM)
+  // Likewise, --plugin-opt=emit-llvm and --plugin-opt=emit-asm are the
+  // options to create output files in bitcode or assembly code
+  // repsectively. No object files are generated.
+  if (config->thinLTOIndexOnly || config->emitLLVM || config->ltoEmitAsm)
     return;
 
   // Apply symbol renames for -wrap.
@@ -1938,8 +1981,17 @@
 
     // We do not want to emit debug sections if --strip-all
     // or -strip-debug are given.
-    return config->strip != StripPolicy::None &&
-           (s->name.startswith(".debug") || s->name.startswith(".zdebug"));
+    if (config->strip == StripPolicy::None)
+      return false;
+
+    if (isDebugSection(*s))
+      return true;
+    if (auto *isec = dyn_cast<InputSection>(s))
+      if (InputSectionBase *rel = isec->getRelocatedSection())
+        if (isDebugSection(*rel))
+          return true;
+
+    return false;
   });
 
   // Now that the number of partitions is fixed, save a pointer to the main
@@ -2043,6 +2095,3 @@
   // Write the result to the file.
   writeResult<ELFT>();
 }
-
-} // namespace elf
-} // namespace lld