vendor/lld/lld-trunk-r338150

1 files changed, 477 insertions, 113 deletions

diff --git a/ELF/Driver.cpp b/ELF/Driver.cpp
index cc76fea2ad5e5..1fc552f011b64 100644
--- a/ELF/Driver.cpp
+++ b/ELF/Driver.cpp
@@ -30,9 +30,9 @@
 #include "InputFiles.h"
 #include "InputSection.h"
 #include "LinkerScript.h"
+#include "MarkLive.h"
 #include "OutputSections.h"
 #include "ScriptParser.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
@@ -42,12 +42,16 @@
 #include "lld/Common/Driver.h"
 #include "lld/Common/ErrorHandler.h"
 #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"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compression.h"
+#include "llvm/Support/LEB128.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
@@ -66,16 +70,18 @@ using namespace lld::elf;
 Configuration *elf::Config;
 LinkerDriver *elf::Driver;
 
-static void setConfigs();
+static void setConfigs(opt::InputArgList &Args);
 
 bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
                raw_ostream &Error) {
-  errorHandler().LogName = Args[0];
+  errorHandler().LogName = sys::path::filename(Args[0]);
   errorHandler().ErrorLimitExceededMsg =
       "too many errors emitted, stopping now (use "
       "-error-limit=0 to see all errors)";
   errorHandler().ErrorOS = &Error;
+  errorHandler().ExitEarly = CanExitEarly;
   errorHandler().ColorDiagnostics = Error.has_colors();
+
   InputSections.clear();
   OutputSections.clear();
   Tar = nullptr;
@@ -88,14 +94,14 @@ bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
   Driver = make<LinkerDriver>();
   Script = make<LinkerScript>();
   Symtab = make<SymbolTable>();
-  Config->Argv = {Args.begin(), Args.end()};
+  Config->ProgName = Args[0];
 
-  Driver->main(Args, CanExitEarly);
+  Driver->main(Args);
 
   // Exit immediately if we don't need to return to the caller.
   // This saves time because the overhead of calling destructors
   // for all globally-allocated objects is not negligible.
-  if (Config->ExitEarly)
+  if (CanExitEarly)
     exitLld(errorCount() ? 1 : 0);
 
   freeArena();
@@ -113,7 +119,8 @@ static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
 
   std::pair<ELFKind, uint16_t> Ret =
       StringSwitch<std::pair<ELFKind, uint16_t>>(S)
-          .Cases("aarch64elf", "aarch64linux", {ELF64LEKind, EM_AARCH64})
+          .Cases("aarch64elf", "aarch64linux", "aarch64_elf64_le_vec",
+                 {ELF64LEKind, EM_AARCH64})
           .Cases("armelf", "armelf_linux_eabi", {ELF32LEKind, EM_ARM})
           .Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
           .Cases("elf32btsmip", "elf32btsmipn32", {ELF32BEKind, EM_MIPS})
@@ -122,6 +129,7 @@ static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
           .Case("elf64btsmip", {ELF64BEKind, EM_MIPS})
           .Case("elf64ltsmip", {ELF64LEKind, EM_MIPS})
           .Case("elf64ppc", {ELF64BEKind, EM_PPC64})
+          .Case("elf64lppc", {ELF64LEKind, EM_PPC64})
           .Cases("elf_amd64", "elf_x86_64", {ELF64LEKind, EM_X86_64})
           .Case("elf_i386", {ELF32LEKind, EM_386})
           .Case("elf_iamcu", {ELF32LEKind, EM_IAMCU})
@@ -228,11 +236,15 @@ void LinkerDriver::addFile(StringRef Path, bool WithLOption) {
     Files.push_back(
         createSharedFile(MBRef, WithLOption ? path::filename(Path) : Path));
     return;
-  default:
+  case file_magic::bitcode:
+  case file_magic::elf_relocatable:
     if (InLib)
       Files.push_back(make<LazyObjFile>(MBRef, "", 0));
     else
       Files.push_back(createObjectFile(MBRef));
+    break;
+  default:
+    error(Path + ": unknown file type");
   }
 }
 
@@ -248,18 +260,11 @@ void LinkerDriver::addLibrary(StringRef Name) {
 // LTO calls LLVM functions to compile bitcode files to native code.
 // Technically this can be delayed until we read bitcode files, but
 // we don't bother to do lazily because the initialization is fast.
-static void initLLVM(opt::InputArgList &Args) {
+static void initLLVM() {
   InitializeAllTargets();
   InitializeAllTargetMCs();
   InitializeAllAsmPrinters();
   InitializeAllAsmParsers();
-
-  // Parse and evaluate -mllvm options.
-  std::vector<const char *> V;
-  V.push_back("lld (LLVM option parsing)");
-  for (auto *Arg : Args.filtered(OPT_mllvm))
-    V.push_back(Arg->getValue());
-  cl::ParseCommandLineOptions(V.size(), V.data());
 }
 
 // Some command line options or some combinations of them are not allowed.
@@ -290,7 +295,9 @@ static void checkOptions(opt::InputArgList &Args) {
       error("-r and -shared may not be used together");
     if (Config->GcSections)
       error("-r and --gc-sections may not be used together");
-    if (Config->ICF)
+    if (Config->GdbIndex)
+      error("-r and --gdb-index may not be used together");
+    if (Config->ICF != ICFLevel::None)
       error("-r and --icf may not be used together");
     if (Config->Pie)
       error("-r and -pie may not be used together");
@@ -310,7 +317,37 @@ static bool hasZOption(opt::InputArgList &Args, StringRef Key) {
   return false;
 }
 
-void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
+static bool getZFlag(opt::InputArgList &Args, StringRef K1, StringRef K2,
+                     bool Default) {
+  for (auto *Arg : Args.filtered_reverse(OPT_z)) {
+    if (K1 == Arg->getValue())
+      return true;
+    if (K2 == Arg->getValue())
+      return false;
+  }
+  return Default;
+}
+
+static bool isKnown(StringRef S) {
+  return S == "combreloc" || S == "copyreloc" || S == "defs" ||
+         S == "execstack" || S == "hazardplt" || S == "initfirst" ||
+         S == "keep-text-section-prefix" || S == "lazy" || S == "muldefs" ||
+         S == "nocombreloc" || S == "nocopyreloc" || S == "nodelete" ||
+         S == "nodlopen" || S == "noexecstack" ||
+         S == "nokeep-text-section-prefix" || S == "norelro" || S == "notext" ||
+         S == "now" || S == "origin" || S == "relro" || S == "retpolineplt" ||
+         S == "rodynamic" || S == "text" || S == "wxneeded" ||
+         S.startswith("max-page-size=") || S.startswith("stack-size=");
+}
+
+// Report an error for an unknown -z option.
+static void checkZOptions(opt::InputArgList &Args) {
+  for (auto *Arg : Args.filtered(OPT_z))
+    if (!isKnown(Arg->getValue()))
+      error("unknown -z value: " + StringRef(Arg->getValue()));
+}
+
+void LinkerDriver::main(ArrayRef<const char *> ArgsArr) {
   ELFOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
 
@@ -319,7 +356,7 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
 
   // Handle -help
   if (Args.hasArg(OPT_help)) {
-    printHelp(ArgsArr[0]);
+    printHelp();
     return;
   }
 
@@ -348,9 +385,6 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   if (Args.hasArg(OPT_version))
     return;
 
-  Config->ExitEarly = CanExitEarly && !Args.hasArg(OPT_full_shutdown);
-  errorHandler().ExitEarly = Config->ExitEarly;
-
   if (const char *Path = getReproduceOption(Args)) {
     // Note that --reproduce is a debug option so you can ignore it
     // if you are trying to understand the whole picture of the code.
@@ -368,10 +402,14 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   }
 
   readConfigs(Args);
-  initLLVM(Args);
+  checkZOptions(Args);
+  initLLVM();
   createFiles(Args);
+  if (errorCount())
+    return;
+
   inferMachineType();
-  setConfigs();
+  setConfigs(Args);
   checkOptions(Args);
   if (errorCount())
     return;
@@ -482,6 +520,15 @@ static StringRef getDynamicLinker(opt::InputArgList &Args) {
   return Arg->getValue();
 }
 
+static ICFLevel getICF(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_icf_none, OPT_icf_safe, OPT_icf_all);
+  if (!Arg || Arg->getOption().getID() == OPT_icf_none)
+    return ICFLevel::None;
+  if (Arg->getOption().getID() == OPT_icf_safe)
+    return ICFLevel::Safe;
+  return ICFLevel::All;
+}
+
 static StripPolicy getStrip(opt::InputArgList &Args) {
   if (Args.hasArg(OPT_relocatable))
     return StripPolicy::None;
@@ -556,6 +603,8 @@ getBuildId(opt::InputArgList &Args) {
     return {BuildIdKind::Fast, {}};
 
   StringRef S = Arg->getValue();
+  if (S == "fast")
+    return {BuildIdKind::Fast, {}};
   if (S == "md5")
     return {BuildIdKind::Md5, {}};
   if (S == "sha1" || S == "tree")
@@ -570,6 +619,57 @@ getBuildId(opt::InputArgList &Args) {
   return {BuildIdKind::None, {}};
 }
 
+static std::pair<bool, bool> getPackDynRelocs(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_pack_dyn_relocs, "none");
+  if (S == "android")
+    return {true, false};
+  if (S == "relr")
+    return {false, true};
+  if (S == "android+relr")
+    return {true, true};
+
+  if (S != "none")
+    error("unknown -pack-dyn-relocs format: " + S);
+  return {false, false};
+}
+
+static void readCallGraph(MemoryBufferRef MB) {
+  // Build a map from symbol name to section
+  DenseMap<StringRef, const Symbol *> SymbolNameToSymbol;
+  for (InputFile *File : ObjectFiles)
+    for (Symbol *Sym : File->getSymbols())
+      SymbolNameToSymbol[Sym->getName()] = Sym;
+
+  for (StringRef L : args::getLines(MB)) {
+    SmallVector<StringRef, 3> Fields;
+    L.split(Fields, ' ');
+    uint64_t Count;
+    if (Fields.size() != 3 || !to_integer(Fields[2], Count))
+      fatal(MB.getBufferIdentifier() + ": parse error");
+    const Symbol *FromSym = SymbolNameToSymbol.lookup(Fields[0]);
+    const Symbol *ToSym = SymbolNameToSymbol.lookup(Fields[1]);
+    if (Config->WarnSymbolOrdering) {
+      if (!FromSym)
+        warn(MB.getBufferIdentifier() + ": no such symbol: " + Fields[0]);
+      if (!ToSym)
+        warn(MB.getBufferIdentifier() + ": no such symbol: " + Fields[1]);
+    }
+    if (!FromSym || !ToSym || Count == 0)
+      continue;
+    warnUnorderableSymbol(FromSym);
+    warnUnorderableSymbol(ToSym);
+    const Defined *FromSymD = dyn_cast<Defined>(FromSym);
+    const Defined *ToSymD = dyn_cast<Defined>(ToSym);
+    if (!FromSymD || !ToSymD)
+      continue;
+    const auto *FromSB = dyn_cast_or_null<InputSectionBase>(FromSymD->Section);
+    const auto *ToSB = dyn_cast_or_null<InputSectionBase>(ToSymD->Section);
+    if (!FromSB || !ToSB)
+      continue;
+    Config->CallGraphProfile[std::make_pair(FromSB, ToSB)] += Count;
+  }
+}
+
 static bool getCompressDebugSections(opt::InputArgList &Args) {
   StringRef S = Args.getLastArgValue(OPT_compress_debug_sections, "none");
   if (S == "none")
@@ -581,54 +681,98 @@ static bool getCompressDebugSections(opt::InputArgList &Args) {
   return true;
 }
 
-static int parseInt(StringRef S, opt::Arg *Arg) {
-  int V = 0;
-  if (!to_integer(S, V, 10))
-    error(Arg->getSpelling() + ": number expected, but got '" + S + "'");
-  return V;
+static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &Args,
+                                                        unsigned Id) {
+  auto *Arg = Args.getLastArg(Id);
+  if (!Arg)
+    return {"", ""};
+
+  StringRef S = Arg->getValue();
+  std::pair<StringRef, StringRef> Ret = S.split(';');
+  if (Ret.second.empty())
+    error(Arg->getSpelling() + " expects 'old;new' format, but got " + S);
+  return Ret;
+}
+
+// Parse the symbol ordering file and warn for any duplicate entries.
+static std::vector<StringRef> getSymbolOrderingFile(MemoryBufferRef MB) {
+  SetVector<StringRef> Names;
+  for (StringRef S : args::getLines(MB))
+    if (!Names.insert(S) && Config->WarnSymbolOrdering)
+      warn(MB.getBufferIdentifier() + ": duplicate ordered symbol: " + S);
+
+  return Names.takeVector();
+}
+
+static void parseClangOption(StringRef Opt, const Twine &Msg) {
+  std::string Err;
+  raw_string_ostream OS(Err);
+
+  const char *Argv[] = {Config->ProgName.data(), Opt.data()};
+  if (cl::ParseCommandLineOptions(2, Argv, "", &OS))
+    return;
+  OS.flush();
+  error(Msg + ": " + StringRef(Err).trim());
 }
 
 // Initializes Config members by the command line options.
 void LinkerDriver::readConfigs(opt::InputArgList &Args) {
+  errorHandler().Verbose = Args.hasArg(OPT_verbose);
+  errorHandler().FatalWarnings =
+      Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
+  ThreadsEnabled = Args.hasFlag(OPT_threads, OPT_no_threads, true);
+
   Config->AllowMultipleDefinition =
-      Args.hasArg(OPT_allow_multiple_definition) || hasZOption(Args, "muldefs");
+      Args.hasFlag(OPT_allow_multiple_definition,
+                   OPT_no_allow_multiple_definition, false) ||
+      hasZOption(Args, "muldefs");
   Config->AuxiliaryList = args::getStrings(Args, OPT_auxiliary);
   Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
   Config->BsymbolicFunctions = Args.hasArg(OPT_Bsymbolic_functions);
+  Config->CheckSections =
+      Args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
   Config->Chroot = Args.getLastArgValue(OPT_chroot);
   Config->CompressDebugSections = getCompressDebugSections(Args);
+  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->Demangle = Args.hasFlag(OPT_demangle, OPT_no_demangle, true);
   Config->DisableVerify = Args.hasArg(OPT_disable_verify);
   Config->Discard = getDiscard(Args);
+  Config->DwoDir = Args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
   Config->DynamicLinker = getDynamicLinker(Args);
   Config->EhFrameHdr =
       Args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
   Config->EmitRelocs = Args.hasArg(OPT_emit_relocs);
-  Config->EnableNewDtags = !Args.hasArg(OPT_disable_new_dtags);
+  Config->EnableNewDtags =
+      Args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
   Config->Entry = Args.getLastArgValue(OPT_entry);
   Config->ExportDynamic =
       Args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false);
-  errorHandler().FatalWarnings =
-      Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
   Config->FilterList = args::getStrings(Args, OPT_filter);
   Config->Fini = Args.getLastArgValue(OPT_fini, "_fini");
   Config->FixCortexA53Errata843419 = Args.hasArg(OPT_fix_cortex_a53_843419);
   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);
-  Config->ICF = Args.hasFlag(OPT_icf_all, OPT_icf_none, false);
-  Config->ICFData = Args.hasArg(OPT_icf_data);
+  Config->ICF = getICF(Args);
+  Config->IgnoreDataAddressEquality =
+      Args.hasArg(OPT_ignore_data_address_equality);
+  Config->IgnoreFunctionAddressEquality =
+      Args.hasArg(OPT_ignore_function_address_equality);
   Config->Init = Args.getLastArgValue(OPT_init, "_init");
   Config->LTOAAPipeline = Args.getLastArgValue(OPT_lto_aa_pipeline);
+  Config->LTODebugPassManager = Args.hasArg(OPT_lto_debug_pass_manager);
+  Config->LTONewPassManager = Args.hasArg(OPT_lto_new_pass_manager);
   Config->LTONewPmPasses = Args.getLastArgValue(OPT_lto_newpm_passes);
   Config->LTOO = args::getInteger(Args, OPT_lto_O, 2);
+  Config->LTOObjPath = Args.getLastArgValue(OPT_plugin_opt_obj_path_eq);
   Config->LTOPartitions = args::getInteger(Args, OPT_lto_partitions, 1);
+  Config->LTOSampleProfile = Args.getLastArgValue(OPT_lto_sample_profile);
   Config->MapFile = Args.getLastArgValue(OPT_Map);
-  Config->NoGnuUnique = Args.hasArg(OPT_no_gnu_unique);
+  Config->MipsGotSize = args::getInteger(Args, OPT_mips_got_size, 0xfff0);
   Config->MergeArmExidx =
       Args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
-  Config->NoUndefinedVersion = Args.hasArg(OPT_no_undefined_version);
   Config->NoinhibitExec = Args.hasArg(OPT_noinhibit_exec);
   Config->Nostdlib = Args.hasArg(OPT_nostdlib);
   Config->OFormatBinary = isOutputFormatBinary(Args);
@@ -638,7 +782,9 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->Optimize = args::getInteger(Args, OPT_O, 1);
   Config->OrphanHandling = getOrphanHandling(Args);
   Config->OutputFile = Args.getLastArgValue(OPT_o);
-  Config->Pie = Args.hasFlag(OPT_pie, OPT_nopie, false);
+  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->Rpath = getRpath(Args);
@@ -658,46 +804,58 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->ThinLTOCachePolicy = CHECK(
       parseCachePruningPolicy(Args.getLastArgValue(OPT_thinlto_cache_policy)),
       "--thinlto-cache-policy: invalid cache policy");
+  Config->ThinLTOEmitImportsFiles =
+      Args.hasArg(OPT_plugin_opt_thinlto_emit_imports_files);
+  Config->ThinLTOIndexOnly = Args.hasArg(OPT_plugin_opt_thinlto_index_only) ||
+                             Args.hasArg(OPT_plugin_opt_thinlto_index_only_eq);
+  Config->ThinLTOIndexOnlyArg =
+      Args.getLastArgValue(OPT_plugin_opt_thinlto_index_only_eq);
   Config->ThinLTOJobs = args::getInteger(Args, OPT_thinlto_jobs, -1u);
-  ThreadsEnabled = Args.hasFlag(OPT_threads, OPT_no_threads, true);
+  Config->ThinLTOObjectSuffixReplace =
+      getOldNewOptions(Args, OPT_plugin_opt_thinlto_object_suffix_replace_eq);
+  Config->ThinLTOPrefixReplace =
+      getOldNewOptions(Args, OPT_plugin_opt_thinlto_prefix_replace_eq);
   Config->Trace = Args.hasArg(OPT_trace);
   Config->Undefined = args::getStrings(Args, OPT_undefined);
+  Config->UndefinedVersion =
+      Args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, true);
+  Config->UseAndroidRelrTags = Args.hasFlag(
+      OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
   Config->UnresolvedSymbols = getUnresolvedSymbolPolicy(Args);
-  Config->Verbose = Args.hasArg(OPT_verbose);
-  errorHandler().Verbose = Config->Verbose;
-  Config->WarnCommon = Args.hasArg(OPT_warn_common);
-  Config->ZCombreloc = !hasZOption(Args, "nocombreloc");
-  Config->ZExecstack = hasZOption(Args, "execstack");
-  Config->ZNocopyreloc = hasZOption(Args, "nocopyreloc");
+  Config->WarnBackrefs =
+      Args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
+  Config->WarnCommon = Args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
+  Config->WarnSymbolOrdering =
+      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->ZExecstack = getZFlag(Args, "execstack", "noexecstack", false);
+  Config->ZHazardplt = hasZOption(Args, "hazardplt");
+  Config->ZInitfirst = hasZOption(Args, "initfirst");
+  Config->ZKeepTextSectionPrefix = getZFlag(
+      Args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
   Config->ZNodelete = hasZOption(Args, "nodelete");
   Config->ZNodlopen = hasZOption(Args, "nodlopen");
-  Config->ZNow = hasZOption(Args, "now");
+  Config->ZNow = getZFlag(Args, "now", "lazy", false);
   Config->ZOrigin = hasZOption(Args, "origin");
-  Config->ZRelro = !hasZOption(Args, "norelro");
+  Config->ZRelro = getZFlag(Args, "relro", "norelro", true);
+  Config->ZRetpolineplt = hasZOption(Args, "retpolineplt");
   Config->ZRodynamic = hasZOption(Args, "rodynamic");
   Config->ZStackSize = args::getZOptionValue(Args, OPT_z, "stack-size", 0);
-  Config->ZText = !hasZOption(Args, "notext");
+  Config->ZText = getZFlag(Args, "text", "notext", true);
   Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
-  // Parse LTO plugin-related options for compatibility with gold.
-  for (auto *Arg : Args.filtered(OPT_plugin_opt, OPT_plugin_opt_eq)) {
-    StringRef S = Arg->getValue();
-    if (S == "disable-verify")
-      Config->DisableVerify = true;
-    else if (S == "save-temps")
-      Config->SaveTemps = true;
-    else if (S.startswith("O"))
-      Config->LTOO = parseInt(S.substr(1), Arg);
-    else if (S.startswith("lto-partitions="))
-      Config->LTOPartitions = parseInt(S.substr(15), Arg);
-    else if (S.startswith("jobs="))
-      Config->ThinLTOJobs = parseInt(S.substr(5), Arg);
-    else if (!S.startswith("/") && !S.startswith("-fresolution=") &&
-             !S.startswith("-pass-through=") && !S.startswith("mcpu=") &&
-             !S.startswith("thinlto") && S != "-function-sections" &&
-             S != "-data-sections")
-      error(Arg->getSpelling() + ": unknown option: " + S);
-  }
+  // Parse LTO options.
+  if (auto *Arg = Args.getLastArg(OPT_plugin_opt_mcpu_eq))
+    parseClangOption(Saver.save("-mcpu=" + StringRef(Arg->getValue())),
+                     Arg->getSpelling());
+
+  for (auto *Arg : Args.filtered(OPT_plugin_opt))
+    parseClangOption(Arg->getValue(), Arg->getSpelling());
+
+  // Parse -mllvm options.
+  for (auto *Arg : Args.filtered(OPT_mllvm))
+    parseClangOption(Arg->getValue(), Arg->getSpelling());
 
   if (Config->LTOO > 3)
     error("invalid optimization level for LTO: " + Twine(Config->LTOO));
@@ -740,17 +898,12 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
 
   std::tie(Config->BuildId, Config->BuildIdVector) = getBuildId(Args);
 
-  if (auto *Arg = Args.getLastArg(OPT_pack_dyn_relocs_eq)) {
-    StringRef S = Arg->getValue();
-    if (S == "android")
-      Config->AndroidPackDynRelocs = true;
-    else if (S != "none")
-      error("unknown -pack-dyn-relocs format: " + S);
-  }
+  std::tie(Config->AndroidPackDynRelocs, Config->RelrPackDynRelocs) =
+      getPackDynRelocs(Args);
 
   if (auto *Arg = Args.getLastArg(OPT_symbol_ordering_file))
     if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
-      Config->SymbolOrderingFile = args::getLines(*Buffer);
+      Config->SymbolOrderingFile = getSymbolOrderingFile(*Buffer);
 
   // If --retain-symbol-file is used, we'll keep only the symbols listed in
   // the file and discard all others.
@@ -778,32 +931,67 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
           {Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
   }
 
+  // If --export-dynamic-symbol=foo is given and symbol foo is defined in
+  // an object file in an archive file, that object file should be pulled
+  // out and linked. (It doesn't have to behave like that from technical
+  // point of view, but this is needed for compatibility with GNU.)
+  for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
+    Config->Undefined.push_back(Arg->getValue());
+
   for (auto *Arg : Args.filtered(OPT_version_script))
-    if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
-      readVersionScript(*Buffer);
+    if (Optional<std::string> Path = searchScript(Arg->getValue())) {
+      if (Optional<MemoryBufferRef> Buffer = readFile(*Path))
+        readVersionScript(*Buffer);
+    } else {
+      error(Twine("cannot find version script ") + Arg->getValue());
+    }
 }
 
 // Some Config members do not directly correspond to any particular
 // command line options, but computed based on other Config values.
 // This function initialize such members. See Config.h for the details
 // of these values.
-static void setConfigs() {
+static void setConfigs(opt::InputArgList &Args) {
   ELFKind Kind = Config->EKind;
   uint16_t Machine = Config->EMachine;
 
-  // There is an ILP32 ABI for x86-64, although it's not very popular.
-  // It is called the x32 ABI.
-  bool IsX32 = (Kind == ELF32LEKind && Machine == EM_X86_64);
-
   Config->CopyRelocs = (Config->Relocatable || Config->EmitRelocs);
   Config->Is64 = (Kind == ELF64LEKind || Kind == ELF64BEKind);
   Config->IsLE = (Kind == ELF32LEKind || Kind == ELF64LEKind);
   Config->Endianness =
       Config->IsLE ? support::endianness::little : support::endianness::big;
   Config->IsMips64EL = (Kind == ELF64LEKind && Machine == EM_MIPS);
-  Config->IsRela = Config->Is64 || IsX32 || Config->MipsN32Abi;
   Config->Pic = Config->Pie || Config->Shared;
   Config->Wordsize = Config->Is64 ? 8 : 4;
+
+  // There is an ILP32 ABI for x86-64, although it's not very popular.
+  // It is called the x32 ABI.
+  bool IsX32 = (Kind == ELF32LEKind && Machine == EM_X86_64);
+
+  // ELF defines two different ways to store relocation addends as shown below:
+  //
+  //  Rel:  Addends are stored to the location where relocations are applied.
+  //  Rela: Addends are stored as part of relocation entry.
+  //
+  // In other words, Rela makes it easy to read addends at the price of extra
+  // 4 or 8 byte for each relocation entry. We don't know why ELF defined two
+  // different mechanisms in the first place, but this is how the spec is
+  // defined.
+  //
+  // You cannot choose which one, Rel or Rela, you want to use. Instead each
+  // ABI defines which one you need to use. The following expression expresses
+  // that.
+  Config->IsRela =
+      (Config->Is64 || IsX32 || Machine == EM_PPC) && Machine != EM_MIPS;
+
+  // If the output uses REL relocations we must store the dynamic relocation
+  // addends to the output sections. We also store addends for RELA relocations
+  // if --apply-dynamic-relocs is used.
+  // We default to not writing the addends when using RELA relocations since
+  // any standard conforming tool can find it in r_addend.
+  Config->WriteAddends = Args.hasFlag(OPT_apply_dynamic_relocs,
+                                      OPT_no_apply_dynamic_relocs, false) ||
+                         !Config->IsRela;
 }
 
 // Returns a value of "-format" option.
@@ -818,6 +1006,10 @@ static bool getBinaryOption(StringRef S) {
 }
 
 void LinkerDriver::createFiles(opt::InputArgList &Args) {
+  // For --{push,pop}-state.
+  std::vector<std::tuple<bool, bool, bool>> Stack;
+
+  // Iterate over argv to process input files and positional arguments.
   for (auto *Arg : Args) {
     switch (Arg->getOption().getUnaliasedOption().getID()) {
     case OPT_library:
@@ -826,8 +1018,15 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
     case OPT_INPUT:
       addFile(Arg->getValue(), /*WithLOption=*/false);
       break;
+    case OPT_defsym: {
+      StringRef From;
+      StringRef To;
+      std::tie(From, To) = StringRef(Arg->getValue()).split('=');
+      readDefsym(From, MemoryBufferRef(To, "-defsym"));
+      break;
+    }
     case OPT_script:
-      if (Optional<std::string> Path = searchLinkerScript(Arg->getValue())) {
+      if (Optional<std::string> Path = searchScript(Arg->getValue())) {
         if (Optional<MemoryBufferRef> MB = readFile(*Path))
           readLinkerScript(*MB);
         break;
@@ -855,11 +1054,48 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
     case OPT_no_whole_archive:
       InWholeArchive = false;
       break;
+    case OPT_just_symbols:
+      if (Optional<MemoryBufferRef> MB = readFile(Arg->getValue())) {
+        Files.push_back(createObjectFile(*MB));
+        Files.back()->JustSymbols = true;
+      }
+      break;
+    case OPT_start_group:
+      if (InputFile::IsInGroup)
+        error("nested --start-group");
+      InputFile::IsInGroup = true;
+      break;
+    case OPT_end_group:
+      if (!InputFile::IsInGroup)
+        error("stray --end-group");
+      InputFile::IsInGroup = false;
+      ++InputFile::NextGroupId;
+      break;
     case OPT_start_lib:
+      if (InLib)
+        error("nested --start-lib");
+      if (InputFile::IsInGroup)
+        error("may not nest --start-lib in --start-group");
       InLib = true;
+      InputFile::IsInGroup = true;
       break;
     case OPT_end_lib:
+      if (!InLib)
+        error("stray --end-lib");
       InLib = false;
+      InputFile::IsInGroup = false;
+      ++InputFile::NextGroupId;
+      break;
+    case OPT_push_state:
+      Stack.emplace_back(Config->AsNeeded, Config->Static, InWholeArchive);
+      break;
+    case OPT_pop_state:
+      if (Stack.empty()) {
+        error("unbalanced --push-state/--pop-state");
+        break;
+      }
+      std::tie(Config->AsNeeded, Config->Static, InWholeArchive) = Stack.back();
+      Stack.pop_back();
       break;
     }
   }
@@ -932,14 +1168,6 @@ static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &Args) {
   return Ret;
 }
 
-static Optional<StringRef> getArchiveName(InputFile *File) {
-  if (isa<ArchiveFile>(File))
-    return File->getName();
-  if (!File->ArchiveName.empty())
-    return File->ArchiveName;
-  return None;
-}
-
 // Handles the -exclude-libs option. If a static library file is specified
 // by the -exclude-libs option, all public symbols from the archive become
 // private unless otherwise specified by version scripts or something.
@@ -947,16 +1175,132 @@ static Optional<StringRef> getArchiveName(InputFile *File) {
 //
 // This is not a popular option, but some programs such as bionic libc use it.
 template <class ELFT>
-static void excludeLibs(opt::InputArgList &Args, ArrayRef<InputFile *> Files) {
+static void excludeLibs(opt::InputArgList &Args) {
   DenseSet<StringRef> Libs = getExcludeLibs(Args);
   bool All = Libs.count("ALL");
 
-  for (InputFile *File : Files)
-    if (Optional<StringRef> Archive = getArchiveName(File))
-      if (All || Libs.count(path::filename(*Archive)))
+  auto Visit = [&](InputFile *File) {
+    if (!File->ArchiveName.empty())
+      if (All || Libs.count(path::filename(File->ArchiveName)))
         for (Symbol *Sym : File->getSymbols())
-          if (!Sym->isLocal())
+          if (!Sym->isLocal() && Sym->File == File)
             Sym->VersionId = VER_NDX_LOCAL;
+  };
+
+  for (InputFile *File : ObjectFiles)
+    Visit(File);
+
+  for (BitcodeFile *File : BitcodeFiles)
+    Visit(File);
+}
+
+// Force Sym to be entered in the output. Used for -u or equivalent.
+template <class ELFT> static void handleUndefined(StringRef Name) {
+  Symbol *Sym = Symtab->find(Name);
+  if (!Sym)
+    return;
+
+  // Since symbol S may not be used inside the program, LTO may
+  // eliminate it. Mark the symbol as "used" to prevent it.
+  Sym->IsUsedInRegularObj = true;
+
+  if (Sym->isLazy())
+    Symtab->fetchLazy<ELFT>(Sym);
+}
+
+template <class ELFT> static bool shouldDemote(Symbol &Sym) {
+  // If all references to a DSO happen to be weak, the DSO is not added to
+  // DT_NEEDED. If that happens, we need to eliminate shared symbols created
+  // from the DSO. Otherwise, they become dangling references that point to a
+  // non-existent DSO.
+  if (auto *S = dyn_cast<SharedSymbol>(&Sym))
+    return !S->getFile<ELFT>().IsNeeded;
+
+  // We are done processing archives, so lazy symbols that were used but not
+  // found can be converted to undefined. We could also just delete the other
+  // lazy symbols, but that seems to be more work than it is worth.
+  return Sym.isLazy() && Sym.IsUsedInRegularObj;
+}
+
+// Some files, such as .so or files between -{start,end}-lib may be removed
+// after their symbols are added to the symbol table. If that happens, we
+// need to remove symbols that refer files that no longer exist, so that
+// they won't appear in the symbol table of the output file.
+//
+// We remove symbols by demoting them to undefined symbol.
+template <class ELFT> static void demoteSymbols() {
+  for (Symbol *Sym : Symtab->getSymbols()) {
+    if (shouldDemote<ELFT>(*Sym)) {
+      bool Used = Sym->Used;
+      replaceSymbol<Undefined>(Sym, nullptr, Sym->getName(), Sym->Binding,
+                               Sym->StOther, Sym->Type);
+      Sym->Used = Used;
+    }
+  }
+}
+
+// The section referred to by S is considered address-significant. Set the
+// KeepUnique flag on the section if appropriate.
+static void markAddrsig(Symbol *S) {
+  if (auto *D = dyn_cast_or_null<Defined>(S))
+    if (D->Section)
+      // We don't need to keep text sections unique under --icf=all even if they
+      // are address-significant.
+      if (Config->ICF == ICFLevel::Safe || !(D->Section->Flags & SHF_EXECINSTR))
+        D->Section->KeepUnique = true;
+}
+
+// Record sections that define symbols mentioned in --keep-unique <symbol>
+// and symbols referred to by address-significance tables. These sections are
+// ineligible for ICF.
+template <class ELFT>
+static void findKeepUniqueSections(opt::InputArgList &Args) {
+  for (auto *Arg : Args.filtered(OPT_keep_unique)) {
+    StringRef Name = Arg->getValue();
+    auto *D = dyn_cast_or_null<Defined>(Symtab->find(Name));
+    if (!D || !D->Section) {
+      warn("could not find symbol " + Name + " to keep unique");
+      continue;
+    }
+    D->Section->KeepUnique = true;
+  }
+
+  // --icf=all --ignore-data-address-equality means that we can ignore
+  // the dynsym and address-significance tables entirely.
+  if (Config->ICF == ICFLevel::All && Config->IgnoreDataAddressEquality)
+    return;
+
+  // Symbols in the dynsym could be address-significant in other executables
+  // or DSOs, so we conservatively mark them as address-significant.
+  for (Symbol *S : Symtab->getSymbols())
+    if (S->includeInDynsym())
+      markAddrsig(S);
+
+  // Visit the address-significance table in each object file and mark each
+  // referenced symbol as address-significant.
+  for (InputFile *F : ObjectFiles) {
+    auto *Obj = cast<ObjFile<ELFT>>(F);
+    ArrayRef<Symbol *> Syms = Obj->getSymbols();
+    if (Obj->AddrsigSec) {
+      ArrayRef<uint8_t> Contents =
+          check(Obj->getObj().getSectionContents(Obj->AddrsigSec));
+      const uint8_t *Cur = Contents.begin();
+      while (Cur != Contents.end()) {
+        unsigned Size;
+        const char *Err;
+        uint64_t SymIndex = decodeULEB128(Cur, &Size, Contents.end(), &Err);
+        if (Err)
+          fatal(toString(F) + ": could not decode addrsig section: " + Err);
+        markAddrsig(Syms[SymIndex]);
+        Cur += Size;
+      }
+    } else {
+      // If an object file does not have an address-significance table,
+      // conservatively mark all of its symbols as address-significant.
+      for (Symbol *S : Syms)
+        markAddrsig(S);
+    }
+  }
 }
 
 // Do actual linking. Note that when this function is called,
@@ -1007,14 +1351,6 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   for (InputFile *F : Files)
     Symtab->addFile<ELFT>(F);
 
-  // Process -defsym option.
-  for (auto *Arg : Args.filtered(OPT_defsym)) {
-    StringRef From;
-    StringRef To;
-    std::tie(From, To) = StringRef(Arg->getValue()).split('=');
-    readDefsym(From, MemoryBufferRef(To, "-defsym"));
-  }
-
   // Now that we have every file, we can decide if we will need a
   // dynamic symbol table.
   // We need one if we were asked to export dynamic symbols or if we are
@@ -1031,23 +1367,29 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
 
   // Handle the `--undefined <sym>` options.
   for (StringRef S : Config->Undefined)
-    Symtab->fetchIfLazy<ELFT>(S);
+    handleUndefined<ELFT>(S);
 
   // If an entry symbol is in a static archive, pull out that file now
   // to complete the symbol table. After this, no new names except a
   // few linker-synthesized ones will be added to the symbol table.
-  Symtab->fetchIfLazy<ELFT>(Config->Entry);
+  handleUndefined<ELFT>(Config->Entry);
 
   // Return if there were name resolution errors.
   if (errorCount())
     return;
 
-  // Handle undefined symbols in DSOs.
-  Symtab->scanShlibUndefined<ELFT>();
+  // Now when we read all script files, we want to finalize order of linker
+  // script commands, which can be not yet final because of INSERT commands.
+  Script->processInsertCommands();
+
+  // We want to declare linker script's symbols early,
+  // so that we can version them.
+  // They also might be exported if referenced by DSOs.
+  Script->declareSymbols();
 
   // Handle the -exclude-libs option.
   if (Args.hasArg(OPT_exclude_libs))
-    excludeLibs<ELFT>(Args, Files);
+    excludeLibs<ELFT>(Args);
 
   // Create ElfHeader early. We need a dummy section in
   // addReservedSymbols to mark the created symbols as not absolute.
@@ -1059,16 +1401,29 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
     addReservedSymbols();
 
   // Apply version scripts.
-  Symtab->scanVersionScript();
+  //
+  // For a relocatable output, version scripts don't make sense, and
+  // parsing a symbol version string (e.g. dropping "@ver1" from a symbol
+  // name "foo@ver1") rather do harm, so we don't call this if -r is given.
+  if (!Config->Relocatable)
+    Symtab->scanVersionScript();
 
   // Create wrapped symbols for -wrap option.
   for (auto *Arg : Args.filtered(OPT_wrap))
     Symtab->addSymbolWrap<ELFT>(Arg->getValue());
 
+  // Do link-time optimization if given files are LLVM bitcode files.
+  // This compiles bitcode files into real object files.
   Symtab->addCombinedLTOObject<ELFT>();
   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;
+
   // Apply symbol renames for -wrap.
   Symtab->applySymbolWrap();
 
@@ -1115,11 +1470,20 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
 
   // Do size optimizations: garbage collection, merging of SHF_MERGE sections
   // and identical code folding.
-  markLive<ELFT>();
   decompressSections();
+  splitSections<ELFT>();
+  markLive<ELFT>();
+  demoteSymbols<ELFT>();
   mergeSections();
-  if (Config->ICF)
+  if (Config->ICF != ICFLevel::None) {
+    findKeepUniqueSections<ELFT>(Args);
     doIcf<ELFT>();
+  }
+
+  // Read the callgraph now that we know what was gced or icfed
+  if (auto *Arg = Args.getLastArg(OPT_call_graph_ordering_file))
+    if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
+      readCallGraph(*Buffer);
 
   // Write the result to the file.
   writeResult<ELFT>();