tools/gold/gold-plugin.cpp

   1 //===-- gold-plugin.cpp - Plugin to gold for Link Time Optimization  ------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This is a gold plugin for LLVM. It provides an LLVM implementation of the
  10 // interface described in http://gcc.gnu.org/wiki/whopr/driver .
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ADT/Statistic.h"
  15 #include "llvm/Bitcode/BitcodeReader.h"
  16 #include "llvm/Bitcode/BitcodeWriter.h"
  17 #include "llvm/CodeGen/CommandFlags.inc"
  18 #include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DiagnosticPrinter.h"
  21 #include "llvm/LTO/Caching.h"
  22 #include "llvm/LTO/LTO.h"
  23 #include "llvm/Object/Error.h"
  24 #include "llvm/Support/CachePruning.h"
  25 #include "llvm/Support/CommandLine.h"
  26 #include "llvm/Support/FileSystem.h"
  27 #include "llvm/Support/ManagedStatic.h"
  28 #include "llvm/Support/MemoryBuffer.h"
  29 #include "llvm/Support/Path.h"
  30 #include "llvm/Support/TargetSelect.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include <list>
  33 #include <map>
  34 #include <plugin-api.h>
  35 #include <string>
  36 #include <system_error>
  37 #include <utility>
  38 #include <vector>
  39
  40 // FIXME: remove this declaration when we stop maintaining Ubuntu Quantal and
  41 // Precise and Debian Wheezy (binutils 2.23 is required)
  42 #define LDPO_PIE 3
  43
  44 #define LDPT_GET_SYMBOLS_V3 28
  45
  46 // FIXME: Remove when binutils 2.31 (containing gold 1.16) is the minimum
  47 // required version.
  48 #define LDPT_GET_WRAP_SYMBOLS 32
  49
  50 using namespace llvm;
  51 using namespace lto;
  52
  53 // FIXME: Remove when binutils 2.31 (containing gold 1.16) is the minimum
  54 // required version.
  55 typedef enum ld_plugin_status (*ld_plugin_get_wrap_symbols)(
  56     uint64_t *num_symbols, const char ***wrap_symbol_list);
  57
  58 static ld_plugin_status discard_message(int level, const char *format, ...) {
  59   // Die loudly. Recent versions of Gold pass ld_plugin_message as the first
  60   // callback in the transfer vector. This should never be called.
  61   abort();
  62 }
  63
  64 static ld_plugin_release_input_file release_input_file = nullptr;
  65 static ld_plugin_get_input_file get_input_file = nullptr;
  66 static ld_plugin_message message = discard_message;
  67 static ld_plugin_get_wrap_symbols get_wrap_symbols = nullptr;
  68
  69 namespace {
  70 struct claimed_file {
  71   void *handle;
  72   void *leader_handle;
  73   std::vector<ld_plugin_symbol> syms;
  74   off_t filesize;
  75   std::string name;
  76 };
  77
  78 /// RAII wrapper to manage opening and releasing of a ld_plugin_input_file.
  79 struct PluginInputFile {
  80   void *Handle;
  81   std::unique_ptr<ld_plugin_input_file> File;
  82
  83   PluginInputFile(void *Handle) : Handle(Handle) {
  84     File = std::make_unique<ld_plugin_input_file>();
  85     if (get_input_file(Handle, File.get()) != LDPS_OK)
  86       message(LDPL_FATAL, "Failed to get file information");
  87   }
  88   ~PluginInputFile() {
  89     // File would have been reset to nullptr if we moved this object
  90     // to a new owner.
  91     if (File)
  92       if (release_input_file(Handle) != LDPS_OK)
  93         message(LDPL_FATAL, "Failed to release file information");
  94   }
  95
  96   ld_plugin_input_file &file() { return *File; }
  97
  98   PluginInputFile(PluginInputFile &&RHS) = default;
  99   PluginInputFile &operator=(PluginInputFile &&RHS) = default;
 100 };
 101
 102 struct ResolutionInfo {
 103   bool CanOmitFromDynSym = true;
 104   bool DefaultVisibility = true;
 105   bool CanInline = true;
 106   bool IsUsedInRegularObj = false;
 107 };
 108
 109 }
 110
 111 static ld_plugin_add_symbols add_symbols = nullptr;
 112 static ld_plugin_get_symbols get_symbols = nullptr;
 113 static ld_plugin_add_input_file add_input_file = nullptr;
 114 static ld_plugin_set_extra_library_path set_extra_library_path = nullptr;
 115 static ld_plugin_get_view get_view = nullptr;
 116 static bool IsExecutable = false;
 117 static bool SplitSections = true;
 118 static Optional<Reloc::Model> RelocationModel = None;
 119 static std::string output_name = "";
 120 static std::list<claimed_file> Modules;
 121 static DenseMap<int, void *> FDToLeaderHandle;
 122 static StringMap<ResolutionInfo> ResInfo;
 123 static std::vector<std::string> Cleanup;
 124
 125 namespace options {
 126   enum OutputType {
 127     OT_NORMAL,
 128     OT_DISABLE,
 129     OT_BC_ONLY,
 130     OT_ASM_ONLY,
 131     OT_SAVE_TEMPS
 132   };
 133   static OutputType TheOutputType = OT_NORMAL;
 134   static unsigned OptLevel = 2;
 135   // Default parallelism of 0 used to indicate that user did not specify.
 136   // Actual parallelism default value depends on implementation.
 137   // Currently only affects ThinLTO, where the default is
 138   // llvm::heavyweight_hardware_concurrency.
 139   static unsigned Parallelism = 0;
 140   // Default regular LTO codegen parallelism (number of partitions).
 141   static unsigned ParallelCodeGenParallelismLevel = 1;
 142 #ifdef NDEBUG
 143   static bool DisableVerify = true;
 144 #else
 145   static bool DisableVerify = false;
 146 #endif
 147   static std::string obj_path;
 148   static std::string extra_library_path;
 149   static std::string triple;
 150   static std::string mcpu;
 151   // When the thinlto plugin option is specified, only read the function
 152   // the information from intermediate files and write a combined
 153   // global index for the ThinLTO backends.
 154   static bool thinlto = false;
 155   // If false, all ThinLTO backend compilations through code gen are performed
 156   // using multiple threads in the gold-plugin, before handing control back to
 157   // gold. If true, write individual backend index files which reflect
 158   // the import decisions, and exit afterwards. The assumption is
 159   // that the build system will launch the backend processes.
 160   static bool thinlto_index_only = false;
 161   // If non-empty, holds the name of a file in which to write the list of
 162   // oject files gold selected for inclusion in the link after symbol
 163   // resolution (i.e. they had selected symbols). This will only be non-empty
 164   // in the thinlto_index_only case. It is used to identify files, which may
 165   // have originally been within archive libraries specified via
 166   // --start-lib/--end-lib pairs, that should be included in the final
 167   // native link process (since intervening function importing and inlining
 168   // may change the symbol resolution detected in the final link and which
 169   // files to include out of --start-lib/--end-lib libraries as a result).
 170   static std::string thinlto_linked_objects_file;
 171   // If true, when generating individual index files for distributed backends,
 172   // also generate a "${bitcodefile}.imports" file at the same location for each
 173   // bitcode file, listing the files it imports from in plain text. This is to
 174   // support distributed build file staging.
 175   static bool thinlto_emit_imports_files = false;
 176   // Option to control where files for a distributed backend (the individual
 177   // index files and optional imports files) are created.
 178   // If specified, expects a string of the form "oldprefix:newprefix", and
 179   // instead of generating these files in the same directory path as the
 180   // corresponding bitcode file, will use a path formed by replacing the
 181   // bitcode file's path prefix matching oldprefix with newprefix.
 182   static std::string thinlto_prefix_replace;
 183   // Option to control the name of modules encoded in the individual index
 184   // files for a distributed backend. This enables the use of minimized
 185   // bitcode files for the thin link, assuming the name of the full bitcode
 186   // file used in the backend differs just in some part of the file suffix.
 187   // If specified, expects a string of the form "oldsuffix:newsuffix".
 188   static std::string thinlto_object_suffix_replace;
 189   // Optional path to a directory for caching ThinLTO objects.
 190   static std::string cache_dir;
 191   // Optional pruning policy for ThinLTO caches.
 192   static std::string cache_policy;
 193   // Additional options to pass into the code generator.
 194   // Note: This array will contain all plugin options which are not claimed
 195   // as plugin exclusive to pass to the code generator.
 196   static std::vector<const char *> extra;
 197   // Sample profile file path
 198   static std::string sample_profile;
 199   // New pass manager
 200   static bool new_pass_manager = false;
 201   // Debug new pass manager
 202   static bool debug_pass_manager = false;
 203   // Directory to store the .dwo files.
 204   static std::string dwo_dir;
 205   /// Statistics output filename.
 206   static std::string stats_file;
 207
 208   // Optimization remarks filename, accepted passes and hotness options
 209   static std::string RemarksFilename;
 210   static std::string RemarksPasses;
 211   static bool RemarksWithHotness = false;
 212   static std::string RemarksFormat;
 213
 214   // Context sensitive PGO options.
 215   static std::string cs_profile_path;
 216   static bool cs_pgo_gen = false;
 217
 218   static void process_plugin_option(const char *opt_)
 219   {
 220     if (opt_ == nullptr)
 221       return;
 222     llvm::StringRef opt = opt_;
 223
 224     if (opt.startswith("mcpu=")) {
 225       mcpu = opt.substr(strlen("mcpu="));
 226     } else if (opt.startswith("extra-library-path=")) {
 227       extra_library_path = opt.substr(strlen("extra_library_path="));
 228     } else if (opt.startswith("mtriple=")) {
 229       triple = opt.substr(strlen("mtriple="));
 230     } else if (opt.startswith("obj-path=")) {
 231       obj_path = opt.substr(strlen("obj-path="));
 232     } else if (opt == "emit-llvm") {
 233       TheOutputType = OT_BC_ONLY;
 234     } else if (opt == "save-temps") {
 235       TheOutputType = OT_SAVE_TEMPS;
 236     } else if (opt == "disable-output") {
 237       TheOutputType = OT_DISABLE;
 238     } else if (opt == "emit-asm") {
 239       TheOutputType = OT_ASM_ONLY;
 240     } else if (opt == "thinlto") {
 241       thinlto = true;
 242     } else if (opt == "thinlto-index-only") {
 243       thinlto_index_only = true;
 244     } else if (opt.startswith("thinlto-index-only=")) {
 245       thinlto_index_only = true;
 246       thinlto_linked_objects_file = opt.substr(strlen("thinlto-index-only="));
 247     } else if (opt == "thinlto-emit-imports-files") {
 248       thinlto_emit_imports_files = true;
 249     } else if (opt.startswith("thinlto-prefix-replace=")) {
 250       thinlto_prefix_replace = opt.substr(strlen("thinlto-prefix-replace="));
 251       if (thinlto_prefix_replace.find(';') == std::string::npos)
 252         message(LDPL_FATAL, "thinlto-prefix-replace expects 'old;new' format");
 253     } else if (opt.startswith("thinlto-object-suffix-replace=")) {
 254       thinlto_object_suffix_replace =
 255           opt.substr(strlen("thinlto-object-suffix-replace="));
 256       if (thinlto_object_suffix_replace.find(';') == std::string::npos)
 257         message(LDPL_FATAL,
 258                 "thinlto-object-suffix-replace expects 'old;new' format");
 259     } else if (opt.startswith("cache-dir=")) {
 260       cache_dir = opt.substr(strlen("cache-dir="));
 261     } else if (opt.startswith("cache-policy=")) {
 262       cache_policy = opt.substr(strlen("cache-policy="));
 263     } else if (opt.size() == 2 && opt[0] == 'O') {
 264       if (opt[1] < '0' || opt[1] > '3')
 265         message(LDPL_FATAL, "Optimization level must be between 0 and 3");
 266       OptLevel = opt[1] - '0';
 267     } else if (opt.startswith("jobs=")) {
 268       if (StringRef(opt_ + 5).getAsInteger(10, Parallelism))
 269         message(LDPL_FATAL, "Invalid parallelism level: %s", opt_ + 5);
 270     } else if (opt.startswith("lto-partitions=")) {
 271       if (opt.substr(strlen("lto-partitions="))
 272               .getAsInteger(10, ParallelCodeGenParallelismLevel))
 273         message(LDPL_FATAL, "Invalid codegen partition level: %s", opt_ + 5);
 274     } else if (opt == "disable-verify") {
 275       DisableVerify = true;
 276     } else if (opt.startswith("sample-profile=")) {
 277       sample_profile = opt.substr(strlen("sample-profile="));
 278     } else if (opt == "cs-profile-generate") {
 279       cs_pgo_gen = true;
 280     } else if (opt.startswith("cs-profile-path=")) {
 281       cs_profile_path = opt.substr(strlen("cs-profile-path="));
 282     } else if (opt == "new-pass-manager") {
 283       new_pass_manager = true;
 284     } else if (opt == "debug-pass-manager") {
 285       debug_pass_manager = true;
 286     } else if (opt.startswith("dwo_dir=")) {
 287       dwo_dir = opt.substr(strlen("dwo_dir="));
 288     } else if (opt.startswith("opt-remarks-filename=")) {
 289       RemarksFilename = opt.substr(strlen("opt-remarks-filename="));
 290     } else if (opt.startswith("opt-remarks-passes=")) {
 291       RemarksPasses = opt.substr(strlen("opt-remarks-passes="));
 292     } else if (opt == "opt-remarks-with-hotness") {
 293       RemarksWithHotness = true;
 294     } else if (opt.startswith("opt-remarks-format=")) {
 295       RemarksFormat = opt.substr(strlen("opt-remarks-format="));
 296     } else if (opt.startswith("stats-file=")) {
 297       stats_file = opt.substr(strlen("stats-file="));
 298     } else {
 299       // Save this option to pass to the code generator.
 300       // ParseCommandLineOptions() expects argv[0] to be program name. Lazily
 301       // add that.
 302       if (extra.empty())
 303         extra.push_back("LLVMgold");
 304
 305       extra.push_back(opt_);
 306     }
 307   }
 308 }
 309
 310 static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
 311                                         int *claimed);
 312 static ld_plugin_status all_symbols_read_hook(void);
 313 static ld_plugin_status cleanup_hook(void);
 314
 315 extern "C" ld_plugin_status onload(ld_plugin_tv *tv);
 316 ld_plugin_status onload(ld_plugin_tv *tv) {
 317   InitializeAllTargetInfos();
 318   InitializeAllTargets();
 319   InitializeAllTargetMCs();
 320   InitializeAllAsmParsers();
 321   InitializeAllAsmPrinters();
 322
 323   // We're given a pointer to the first transfer vector. We read through them
 324   // until we find one where tv_tag == LDPT_NULL. The REGISTER_* tagged values
 325   // contain pointers to functions that we need to call to register our own
 326   // hooks. The others are addresses of functions we can use to call into gold
 327   // for services.
 328
 329   bool registeredClaimFile = false;
 330   bool RegisteredAllSymbolsRead = false;
 331
 332   for (; tv->tv_tag != LDPT_NULL; ++tv) {
 333     // Cast tv_tag to int to allow values not in "enum ld_plugin_tag", like, for
 334     // example, LDPT_GET_SYMBOLS_V3 when building against an older plugin-api.h
 335     // header.
 336     switch (static_cast<int>(tv->tv_tag)) {
 337     case LDPT_OUTPUT_NAME:
 338       output_name = tv->tv_u.tv_string;
 339       break;
 340     case LDPT_LINKER_OUTPUT:
 341       switch (tv->tv_u.tv_val) {
 342       case LDPO_REL: // .o
 343         IsExecutable = false;
 344         SplitSections = false;
 345         break;
 346       case LDPO_DYN: // .so
 347         IsExecutable = false;
 348         RelocationModel = Reloc::PIC_;
 349         break;
 350       case LDPO_PIE: // position independent executable
 351         IsExecutable = true;
 352         RelocationModel = Reloc::PIC_;
 353         break;
 354       case LDPO_EXEC: // .exe
 355         IsExecutable = true;
 356         RelocationModel = Reloc::Static;
 357         break;
 358       default:
 359         message(LDPL_ERROR, "Unknown output file type %d", tv->tv_u.tv_val);
 360         return LDPS_ERR;
 361       }
 362       break;
 363     case LDPT_OPTION:
 364       options::process_plugin_option(tv->tv_u.tv_string);
 365       break;
 366     case LDPT_REGISTER_CLAIM_FILE_HOOK: {
 367       ld_plugin_register_claim_file callback;
 368       callback = tv->tv_u.tv_register_claim_file;
 369
 370       if (callback(claim_file_hook) != LDPS_OK)
 371         return LDPS_ERR;
 372
 373       registeredClaimFile = true;
 374     } break;
 375     case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK: {
 376       ld_plugin_register_all_symbols_read callback;
 377       callback = tv->tv_u.tv_register_all_symbols_read;
 378
 379       if (callback(all_symbols_read_hook) != LDPS_OK)
 380         return LDPS_ERR;
 381
 382       RegisteredAllSymbolsRead = true;
 383     } break;
 384     case LDPT_REGISTER_CLEANUP_HOOK: {
 385       ld_plugin_register_cleanup callback;
 386       callback = tv->tv_u.tv_register_cleanup;
 387
 388       if (callback(cleanup_hook) != LDPS_OK)
 389         return LDPS_ERR;
 390     } break;
 391     case LDPT_GET_INPUT_FILE:
 392       get_input_file = tv->tv_u.tv_get_input_file;
 393       break;
 394     case LDPT_RELEASE_INPUT_FILE:
 395       release_input_file = tv->tv_u.tv_release_input_file;
 396       break;
 397     case LDPT_ADD_SYMBOLS:
 398       add_symbols = tv->tv_u.tv_add_symbols;
 399       break;
 400     case LDPT_GET_SYMBOLS_V2:
 401       // Do not override get_symbols_v3 with get_symbols_v2.
 402       if (!get_symbols)
 403         get_symbols = tv->tv_u.tv_get_symbols;
 404       break;
 405     case LDPT_GET_SYMBOLS_V3:
 406       get_symbols = tv->tv_u.tv_get_symbols;
 407       break;
 408     case LDPT_ADD_INPUT_FILE:
 409       add_input_file = tv->tv_u.tv_add_input_file;
 410       break;
 411     case LDPT_SET_EXTRA_LIBRARY_PATH:
 412       set_extra_library_path = tv->tv_u.tv_set_extra_library_path;
 413       break;
 414     case LDPT_GET_VIEW:
 415       get_view = tv->tv_u.tv_get_view;
 416       break;
 417     case LDPT_MESSAGE:
 418       message = tv->tv_u.tv_message;
 419       break;
 420     case LDPT_GET_WRAP_SYMBOLS:
 421       // FIXME: When binutils 2.31 (containing gold 1.16) is the minimum
 422       // required version, this should be changed to:
 423       // get_wrap_symbols = tv->tv_u.tv_get_wrap_symbols;
 424       get_wrap_symbols =
 425           (ld_plugin_get_wrap_symbols)tv->tv_u.tv_message;
 426       break;
 427     default:
 428       break;
 429     }
 430   }
 431
 432   if (!registeredClaimFile) {
 433     message(LDPL_ERROR, "register_claim_file not passed to LLVMgold.");
 434     return LDPS_ERR;
 435   }
 436   if (!add_symbols) {
 437     message(LDPL_ERROR, "add_symbols not passed to LLVMgold.");
 438     return LDPS_ERR;
 439   }
 440
 441   if (!RegisteredAllSymbolsRead)
 442     return LDPS_OK;
 443
 444   if (!get_input_file) {
 445     message(LDPL_ERROR, "get_input_file not passed to LLVMgold.");
 446     return LDPS_ERR;
 447   }
 448   if (!release_input_file) {
 449     message(LDPL_ERROR, "release_input_file not passed to LLVMgold.");
 450     return LDPS_ERR;
 451   }
 452
 453   return LDPS_OK;
 454 }
 455
 456 static void diagnosticHandler(const DiagnosticInfo &DI) {
 457   std::string ErrStorage;
 458   {
 459     raw_string_ostream OS(ErrStorage);
 460     DiagnosticPrinterRawOStream DP(OS);
 461     DI.print(DP);
 462   }
 463   ld_plugin_level Level;
 464   switch (DI.getSeverity()) {
 465   case DS_Error:
 466     Level = LDPL_FATAL;
 467     break;
 468   case DS_Warning:
 469     Level = LDPL_WARNING;
 470     break;
 471   case DS_Note:
 472   case DS_Remark:
 473     Level = LDPL_INFO;
 474     break;
 475   }
 476   message(Level, "LLVM gold plugin: %s",  ErrStorage.c_str());
 477 }
 478
 479 static void check(Error E, std::string Msg = "LLVM gold plugin") {
 480   handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) -> Error {
 481     message(LDPL_FATAL, "%s: %s", Msg.c_str(), EIB.message().c_str());
 482     return Error::success();
 483   });
 484 }
 485
 486 template <typename T> static T check(Expected<T> E) {
 487   if (E)
 488     return std::move(*E);
 489   check(E.takeError());
 490   return T();
 491 }
 492
 493 /// Called by gold to see whether this file is one that our plugin can handle.
 494 /// We'll try to open it and register all the symbols with add_symbol if
 495 /// possible.
 496 static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
 497                                         int *claimed) {
 498   MemoryBufferRef BufferRef;
 499   std::unique_ptr<MemoryBuffer> Buffer;
 500   if (get_view) {
 501     const void *view;
 502     if (get_view(file->handle, &view) != LDPS_OK) {
 503       message(LDPL_ERROR, "Failed to get a view of %s", file->name);
 504       return LDPS_ERR;
 505     }
 506     BufferRef =
 507         MemoryBufferRef(StringRef((const char *)view, file->filesize), "");
 508   } else {
 509     int64_t offset = 0;
 510     // Gold has found what might be IR part-way inside of a file, such as
 511     // an .a archive.
 512     if (file->offset) {
 513       offset = file->offset;
 514     }
 515     ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
 516         MemoryBuffer::getOpenFileSlice(sys::fs::convertFDToNativeFile(file->fd),
 517                                        file->name, file->filesize, offset);
 518     if (std::error_code EC = BufferOrErr.getError()) {
 519       message(LDPL_ERROR, EC.message().c_str());
 520       return LDPS_ERR;
 521     }
 522     Buffer = std::move(BufferOrErr.get());
 523     BufferRef = Buffer->getMemBufferRef();
 524   }
 525
 526   *claimed = 1;
 527
 528   Expected<std::unique_ptr<InputFile>> ObjOrErr = InputFile::create(BufferRef);
 529   if (!ObjOrErr) {
 530     handleAllErrors(ObjOrErr.takeError(), [&](const ErrorInfoBase &EI) {
 531       std::error_code EC = EI.convertToErrorCode();
 532       if (EC == object::object_error::invalid_file_type ||
 533           EC == object::object_error::bitcode_section_not_found)
 534         *claimed = 0;
 535       else
 536         message(LDPL_FATAL,
 537                 "LLVM gold plugin has failed to create LTO module: %s",
 538                 EI.message().c_str());
 539     });
 540
 541     return *claimed ? LDPS_ERR : LDPS_OK;
 542   }
 543
 544   std::unique_ptr<InputFile> Obj = std::move(*ObjOrErr);
 545
 546   Modules.emplace_back();
 547   claimed_file &cf = Modules.back();
 548
 549   cf.handle = file->handle;
 550   // Keep track of the first handle for each file descriptor, since there are
 551   // multiple in the case of an archive. This is used later in the case of
 552   // ThinLTO parallel backends to ensure that each file is only opened and
 553   // released once.
 554   auto LeaderHandle =
 555       FDToLeaderHandle.insert(std::make_pair(file->fd, file->handle)).first;
 556   cf.leader_handle = LeaderHandle->second;
 557   // Save the filesize since for parallel ThinLTO backends we can only
 558   // invoke get_input_file once per archive (only for the leader handle).
 559   cf.filesize = file->filesize;
 560   // In the case of an archive library, all but the first member must have a
 561   // non-zero offset, which we can append to the file name to obtain a
 562   // unique name.
 563   cf.name = file->name;
 564   if (file->offset)
 565     cf.name += ".llvm." + std::to_string(file->offset) + "." +
 566                sys::path::filename(Obj->getSourceFileName()).str();
 567
 568   for (auto &Sym : Obj->symbols()) {
 569     cf.syms.push_back(ld_plugin_symbol());
 570     ld_plugin_symbol &sym = cf.syms.back();
 571     sym.version = nullptr;
 572     StringRef Name = Sym.getName();
 573     sym.name = strdup(Name.str().c_str());
 574
 575     ResolutionInfo &Res = ResInfo[Name];
 576
 577     Res.CanOmitFromDynSym &= Sym.canBeOmittedFromSymbolTable();
 578
 579     sym.visibility = LDPV_DEFAULT;
 580     GlobalValue::VisibilityTypes Vis = Sym.getVisibility();
 581     if (Vis != GlobalValue::DefaultVisibility)
 582       Res.DefaultVisibility = false;
 583     switch (Vis) {
 584     case GlobalValue::DefaultVisibility:
 585       break;
 586     case GlobalValue::HiddenVisibility:
 587       sym.visibility = LDPV_HIDDEN;
 588       break;
 589     case GlobalValue::ProtectedVisibility:
 590       sym.visibility = LDPV_PROTECTED;
 591       break;
 592     }
 593
 594     if (Sym.isUndefined()) {
 595       sym.def = LDPK_UNDEF;
 596       if (Sym.isWeak())
 597         sym.def = LDPK_WEAKUNDEF;
 598     } else if (Sym.isCommon())
 599       sym.def = LDPK_COMMON;
 600     else if (Sym.isWeak())
 601       sym.def = LDPK_WEAKDEF;
 602     else
 603       sym.def = LDPK_DEF;
 604
 605     sym.size = 0;
 606     sym.comdat_key = nullptr;
 607     int CI = Sym.getComdatIndex();
 608     if (CI != -1) {
 609       StringRef C = Obj->getComdatTable()[CI];
 610       sym.comdat_key = strdup(C.str().c_str());
 611     }
 612
 613     sym.resolution = LDPR_UNKNOWN;
 614   }
 615
 616   if (!cf.syms.empty()) {
 617     if (add_symbols(cf.handle, cf.syms.size(), cf.syms.data()) != LDPS_OK) {
 618       message(LDPL_ERROR, "Unable to add symbols!");
 619       return LDPS_ERR;
 620     }
 621   }
 622
 623   // Handle any --wrap options passed to gold, which are than passed
 624   // along to the plugin.
 625   if (get_wrap_symbols) {
 626     const char **wrap_symbols;
 627     uint64_t count = 0;
 628     if (get_wrap_symbols(&count, &wrap_symbols) != LDPS_OK) {
 629       message(LDPL_ERROR, "Unable to get wrap symbols!");
 630       return LDPS_ERR;
 631     }
 632     for (uint64_t i = 0; i < count; i++) {
 633       StringRef Name = wrap_symbols[i];
 634       ResolutionInfo &Res = ResInfo[Name];
 635       ResolutionInfo &WrapRes = ResInfo["__wrap_" + Name.str()];
 636       ResolutionInfo &RealRes = ResInfo["__real_" + Name.str()];
 637       // Tell LTO not to inline symbols that will be overwritten.
 638       Res.CanInline = false;
 639       RealRes.CanInline = false;
 640       // Tell LTO not to eliminate symbols that will be used after renaming.
 641       Res.IsUsedInRegularObj = true;
 642       WrapRes.IsUsedInRegularObj = true;
 643     }
 644   }
 645
 646   return LDPS_OK;
 647 }
 648
 649 static void freeSymName(ld_plugin_symbol &Sym) {
 650   free(Sym.name);
 651   free(Sym.comdat_key);
 652   Sym.name = nullptr;
 653   Sym.comdat_key = nullptr;
 654 }
 655
 656 /// Helper to get a file's symbols and a view into it via gold callbacks.
 657 static const void *getSymbolsAndView(claimed_file &F) {
 658   ld_plugin_status status = get_symbols(F.handle, F.syms.size(), F.syms.data());
 659   if (status == LDPS_NO_SYMS)
 660     return nullptr;
 661
 662   if (status != LDPS_OK)
 663     message(LDPL_FATAL, "Failed to get symbol information");
 664
 665   const void *View;
 666   if (get_view(F.handle, &View) != LDPS_OK)
 667     message(LDPL_FATAL, "Failed to get a view of file");
 668
 669   return View;
 670 }
 671
 672 /// Parse the thinlto-object-suffix-replace option into the \p OldSuffix and
 673 /// \p NewSuffix strings, if it was specified.
 674 static void getThinLTOOldAndNewSuffix(std::string &OldSuffix,
 675                                       std::string &NewSuffix) {
 676   assert(options::thinlto_object_suffix_replace.empty() ||
 677          options::thinlto_object_suffix_replace.find(";") != StringRef::npos);
 678   StringRef SuffixReplace = options::thinlto_object_suffix_replace;
 679   std::tie(OldSuffix, NewSuffix) = SuffixReplace.split(';');
 680 }
 681
 682 /// Given the original \p Path to an output file, replace any filename
 683 /// suffix matching \p OldSuffix with \p NewSuffix.
 684 static std::string getThinLTOObjectFileName(StringRef Path, StringRef OldSuffix,
 685                                             StringRef NewSuffix) {
 686   if (Path.consume_back(OldSuffix))
 687     return (Path + NewSuffix).str();
 688   return Path;
 689 }
 690
 691 // Returns true if S is valid as a C language identifier.
 692 static bool isValidCIdentifier(StringRef S) {
 693   return !S.empty() && (isAlpha(S[0]) || S[0] == '_') &&
 694          std::all_of(S.begin() + 1, S.end(),
 695                      [](char C) { return C == '_' || isAlnum(C); });
 696 }
 697
 698 static bool isUndefined(ld_plugin_symbol &Sym) {
 699   return Sym.def == LDPK_UNDEF || Sym.def == LDPK_WEAKUNDEF;
 700 }
 701
 702 static void addModule(LTO &Lto, claimed_file &F, const void *View,
 703                       StringRef Filename) {
 704   MemoryBufferRef BufferRef(StringRef((const char *)View, F.filesize),
 705                             Filename);
 706   Expected<std::unique_ptr<InputFile>> ObjOrErr = InputFile::create(BufferRef);
 707
 708   if (!ObjOrErr)
 709     message(LDPL_FATAL, "Could not read bitcode from file : %s",
 710             toString(ObjOrErr.takeError()).c_str());
 711
 712   unsigned SymNum = 0;
 713   std::unique_ptr<InputFile> Input = std::move(ObjOrErr.get());
 714   auto InputFileSyms = Input->symbols();
 715   assert(InputFileSyms.size() == F.syms.size());
 716   std::vector<SymbolResolution> Resols(F.syms.size());
 717   for (ld_plugin_symbol &Sym : F.syms) {
 718     const InputFile::Symbol &InpSym = InputFileSyms[SymNum];
 719     SymbolResolution &R = Resols[SymNum++];
 720
 721     ld_plugin_symbol_resolution Resolution =
 722         (ld_plugin_symbol_resolution)Sym.resolution;
 723
 724     ResolutionInfo &Res = ResInfo[Sym.name];
 725
 726     switch (Resolution) {
 727     case LDPR_UNKNOWN:
 728       llvm_unreachable("Unexpected resolution");
 729
 730     case LDPR_RESOLVED_IR:
 731     case LDPR_RESOLVED_EXEC:
 732     case LDPR_RESOLVED_DYN:
 733     case LDPR_PREEMPTED_IR:
 734     case LDPR_PREEMPTED_REG:
 735     case LDPR_UNDEF:
 736       break;
 737
 738     case LDPR_PREVAILING_DEF_IRONLY:
 739       R.Prevailing = !isUndefined(Sym);
 740       break;
 741
 742     case LDPR_PREVAILING_DEF:
 743       R.Prevailing = !isUndefined(Sym);
 744       R.VisibleToRegularObj = true;
 745       break;
 746
 747     case LDPR_PREVAILING_DEF_IRONLY_EXP:
 748       R.Prevailing = !isUndefined(Sym);
 749       if (!Res.CanOmitFromDynSym)
 750         R.VisibleToRegularObj = true;
 751       break;
 752     }
 753
 754     // If the symbol has a C identifier section name, we need to mark
 755     // it as visible to a regular object so that LTO will keep it around
 756     // to ensure the linker generates special __start_<secname> and
 757     // __stop_<secname> symbols which may be used elsewhere.
 758     if (isValidCIdentifier(InpSym.getSectionName()))
 759       R.VisibleToRegularObj = true;
 760
 761     if (Resolution != LDPR_RESOLVED_DYN && Resolution != LDPR_UNDEF &&
 762         (IsExecutable || !Res.DefaultVisibility))
 763       R.FinalDefinitionInLinkageUnit = true;
 764
 765     if (!Res.CanInline)
 766       R.LinkerRedefined = true;
 767
 768     if (Res.IsUsedInRegularObj)
 769       R.VisibleToRegularObj = true;
 770
 771     freeSymName(Sym);
 772   }
 773
 774   check(Lto.add(std::move(Input), Resols),
 775         std::string("Failed to link module ") + F.name);
 776 }
 777
 778 static void recordFile(const std::string &Filename, bool TempOutFile) {
 779   if (add_input_file(Filename.c_str()) != LDPS_OK)
 780     message(LDPL_FATAL,
 781             "Unable to add .o file to the link. File left behind in: %s",
 782             Filename.c_str());
 783   if (TempOutFile)
 784     Cleanup.push_back(Filename);
 785 }
 786
 787 /// Return the desired output filename given a base input name, a flag
 788 /// indicating whether a temp file should be generated, and an optional task id.
 789 /// The new filename generated is returned in \p NewFilename.
 790 static int getOutputFileName(StringRef InFilename, bool TempOutFile,
 791                              SmallString<128> &NewFilename, int TaskID) {
 792   int FD = -1;
 793   if (TempOutFile) {
 794     std::error_code EC =
 795         sys::fs::createTemporaryFile("lto-llvm", "o", FD, NewFilename);
 796     if (EC)
 797       message(LDPL_FATAL, "Could not create temporary file: %s",
 798               EC.message().c_str());
 799   } else {
 800     NewFilename = InFilename;
 801     if (TaskID > 0)
 802       NewFilename += utostr(TaskID);
 803     std::error_code EC =
 804         sys::fs::openFileForWrite(NewFilename, FD, sys::fs::CD_CreateAlways);
 805     if (EC)
 806       message(LDPL_FATAL, "Could not open file %s: %s", NewFilename.c_str(),
 807               EC.message().c_str());
 808   }
 809   return FD;
 810 }
 811
 812 static CodeGenOpt::Level getCGOptLevel() {
 813   switch (options::OptLevel) {
 814   case 0:
 815     return CodeGenOpt::None;
 816   case 1:
 817     return CodeGenOpt::Less;
 818   case 2:
 819     return CodeGenOpt::Default;
 820   case 3:
 821     return CodeGenOpt::Aggressive;
 822   }
 823   llvm_unreachable("Invalid optimization level");
 824 }
 825
 826 /// Parse the thinlto_prefix_replace option into the \p OldPrefix and
 827 /// \p NewPrefix strings, if it was specified.
 828 static void getThinLTOOldAndNewPrefix(std::string &OldPrefix,
 829                                       std::string &NewPrefix) {
 830   StringRef PrefixReplace = options::thinlto_prefix_replace;
 831   assert(PrefixReplace.empty() || PrefixReplace.find(";") != StringRef::npos);
 832   std::tie(OldPrefix, NewPrefix) = PrefixReplace.split(';');
 833 }
 834
 835 /// Creates instance of LTO.
 836 /// OnIndexWrite is callback to let caller know when LTO writes index files.
 837 /// LinkedObjectsFile is an output stream to write the list of object files for
 838 /// the final ThinLTO linking. Can be nullptr.
 839 static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
 840                                       raw_fd_ostream *LinkedObjectsFile) {
 841   Config Conf;
 842   ThinBackend Backend;
 843
 844   Conf.CPU = options::mcpu;
 845   Conf.Options = InitTargetOptionsFromCodeGenFlags();
 846
 847   // Disable the new X86 relax relocations since gold might not support them.
 848   // FIXME: Check the gold version or add a new option to enable them.
 849   Conf.Options.RelaxELFRelocations = false;
 850
 851   // Toggle function/data sections.
 852   if (FunctionSections.getNumOccurrences() == 0)
 853     Conf.Options.FunctionSections = SplitSections;
 854   if (DataSections.getNumOccurrences() == 0)
 855     Conf.Options.DataSections = SplitSections;
 856
 857   Conf.MAttrs = MAttrs;
 858   Conf.RelocModel = RelocationModel;
 859   Conf.CodeModel = getCodeModel();
 860   Conf.CGOptLevel = getCGOptLevel();
 861   Conf.DisableVerify = options::DisableVerify;
 862   Conf.OptLevel = options::OptLevel;
 863   if (options::Parallelism)
 864     Backend = createInProcessThinBackend(options::Parallelism);
 865   if (options::thinlto_index_only) {
 866     std::string OldPrefix, NewPrefix;
 867     getThinLTOOldAndNewPrefix(OldPrefix, NewPrefix);
 868     Backend = createWriteIndexesThinBackend(OldPrefix, NewPrefix,
 869                                             options::thinlto_emit_imports_files,
 870                                             LinkedObjectsFile, OnIndexWrite);
 871   }
 872
 873   Conf.OverrideTriple = options::triple;
 874   Conf.DefaultTriple = sys::getDefaultTargetTriple();
 875
 876   Conf.DiagHandler = diagnosticHandler;
 877
 878   switch (options::TheOutputType) {
 879   case options::OT_NORMAL:
 880     break;
 881
 882   case options::OT_DISABLE:
 883     Conf.PreOptModuleHook = [](size_t Task, const Module &M) { return false; };
 884     break;
 885
 886   case options::OT_BC_ONLY:
 887     Conf.PostInternalizeModuleHook = [](size_t Task, const Module &M) {
 888       std::error_code EC;
 889       raw_fd_ostream OS(output_name, EC, sys::fs::OpenFlags::OF_None);
 890       if (EC)
 891         message(LDPL_FATAL, "Failed to write the output file.");
 892       WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ false);
 893       return false;
 894     };
 895     break;
 896
 897   case options::OT_SAVE_TEMPS:
 898     check(Conf.addSaveTemps(output_name + ".",
 899                             /* UseInputModulePath */ true));
 900     break;
 901   case options::OT_ASM_ONLY:
 902     Conf.CGFileType = TargetMachine::CGFT_AssemblyFile;
 903     break;
 904   }
 905
 906   if (!options::sample_profile.empty())
 907     Conf.SampleProfile = options::sample_profile;
 908
 909   if (!options::cs_profile_path.empty())
 910     Conf.CSIRProfile = options::cs_profile_path;
 911   Conf.RunCSIRInstr = options::cs_pgo_gen;
 912
 913   Conf.DwoDir = options::dwo_dir;
 914
 915   // Set up optimization remarks handling.
 916   Conf.RemarksFilename = options::RemarksFilename;
 917   Conf.RemarksPasses = options::RemarksPasses;
 918   Conf.RemarksWithHotness = options::RemarksWithHotness;
 919   Conf.RemarksFormat = options::RemarksFormat;
 920
 921   // Use new pass manager if set in driver
 922   Conf.UseNewPM = options::new_pass_manager;
 923   // Debug new pass manager if requested
 924   Conf.DebugPassManager = options::debug_pass_manager;
 925
 926   Conf.StatsFile = options::stats_file;
 927   return std::make_unique<LTO>(std::move(Conf), Backend,
 928                                 options::ParallelCodeGenParallelismLevel);
 929 }
 930
 931 // Write empty files that may be expected by a distributed build
 932 // system when invoked with thinlto_index_only. This is invoked when
 933 // the linker has decided not to include the given module in the
 934 // final link. Frequently the distributed build system will want to
 935 // confirm that all expected outputs are created based on all of the
 936 // modules provided to the linker.
 937 // If SkipModule is true then .thinlto.bc should contain just
 938 // SkipModuleByDistributedBackend flag which requests distributed backend
 939 // to skip the compilation of the corresponding module and produce an empty
 940 // object file.
 941 static void writeEmptyDistributedBuildOutputs(const std::string &ModulePath,
 942                                               const std::string &OldPrefix,
 943                                               const std::string &NewPrefix,
 944                                               bool SkipModule) {
 945   std::string NewModulePath =
 946       getThinLTOOutputFile(ModulePath, OldPrefix, NewPrefix);
 947   std::error_code EC;
 948   {
 949     raw_fd_ostream OS(NewModulePath + ".thinlto.bc", EC,
 950                       sys::fs::OpenFlags::OF_None);
 951     if (EC)
 952       message(LDPL_FATAL, "Failed to write '%s': %s",
 953               (NewModulePath + ".thinlto.bc").c_str(), EC.message().c_str());
 954
 955     if (SkipModule) {
 956       ModuleSummaryIndex Index(/*HaveGVs*/ false);
 957       Index.setSkipModuleByDistributedBackend();
 958       WriteIndexToFile(Index, OS, nullptr);
 959     }
 960   }
 961   if (options::thinlto_emit_imports_files) {
 962     raw_fd_ostream OS(NewModulePath + ".imports", EC,
 963                       sys::fs::OpenFlags::OF_None);
 964     if (EC)
 965       message(LDPL_FATAL, "Failed to write '%s': %s",
 966               (NewModulePath + ".imports").c_str(), EC.message().c_str());
 967   }
 968 }
 969
 970 // Creates and returns output stream with a list of object files for final
 971 // linking of distributed ThinLTO.
 972 static std::unique_ptr<raw_fd_ostream> CreateLinkedObjectsFile() {
 973   if (options::thinlto_linked_objects_file.empty())
 974     return nullptr;
 975   assert(options::thinlto_index_only);
 976   std::error_code EC;
 977   auto LinkedObjectsFile = std::make_unique<raw_fd_ostream>(
 978       options::thinlto_linked_objects_file, EC, sys::fs::OpenFlags::OF_None);
 979   if (EC)
 980     message(LDPL_FATAL, "Failed to create '%s': %s",
 981             options::thinlto_linked_objects_file.c_str(), EC.message().c_str());
 982   return LinkedObjectsFile;
 983 }
 984
 985 /// Runs LTO and return a list of pairs <FileName, IsTemporary>.
 986 static std::vector<std::pair<SmallString<128>, bool>> runLTO() {
 987   // Map to own RAII objects that manage the file opening and releasing
 988   // interfaces with gold. This is needed only for ThinLTO mode, since
 989   // unlike regular LTO, where addModule will result in the opened file
 990   // being merged into a new combined module, we need to keep these files open
 991   // through Lto->run().
 992   DenseMap<void *, std::unique_ptr<PluginInputFile>> HandleToInputFile;
 993
 994   // Owns string objects and tells if index file was already created.
 995   StringMap<bool> ObjectToIndexFileState;
 996
 997   std::unique_ptr<raw_fd_ostream> LinkedObjects = CreateLinkedObjectsFile();
 998   std::unique_ptr<LTO> Lto = createLTO(
 999       [&ObjectToIndexFileState](const std::string &Identifier) {
1000         ObjectToIndexFileState[Identifier] = true;
1001       },
1002       LinkedObjects.get());
1003
1004   std::string OldPrefix, NewPrefix;
1005   if (options::thinlto_index_only)
1006     getThinLTOOldAndNewPrefix(OldPrefix, NewPrefix);
1007
1008   std::string OldSuffix, NewSuffix;
1009   getThinLTOOldAndNewSuffix(OldSuffix, NewSuffix);
1010
1011   for (claimed_file &F : Modules) {
1012     if (options::thinlto && !HandleToInputFile.count(F.leader_handle))
1013       HandleToInputFile.insert(std::make_pair(
1014           F.leader_handle, std::make_unique<PluginInputFile>(F.handle)));
1015     // In case we are thin linking with a minimized bitcode file, ensure
1016     // the module paths encoded in the index reflect where the backends
1017     // will locate the full bitcode files for compiling/importing.
1018     std::string Identifier =
1019         getThinLTOObjectFileName(F.name, OldSuffix, NewSuffix);
1020     auto ObjFilename = ObjectToIndexFileState.insert({Identifier, false});
1021     assert(ObjFilename.second);
1022     if (const void *View = getSymbolsAndView(F))
1023       addModule(*Lto, F, View, ObjFilename.first->first());
1024     else if (options::thinlto_index_only) {
1025       ObjFilename.first->second = true;
1026       writeEmptyDistributedBuildOutputs(Identifier, OldPrefix, NewPrefix,
1027                                         /* SkipModule */ true);
1028     }
1029   }
1030
1031   SmallString<128> Filename;
1032   // Note that getOutputFileName will append a unique ID for each task
1033   if (!options::obj_path.empty())
1034     Filename = options::obj_path;
1035   else if (options::TheOutputType == options::OT_SAVE_TEMPS)
1036     Filename = output_name + ".o";
1037   else if (options::TheOutputType == options::OT_ASM_ONLY)
1038     Filename = output_name;
1039   bool SaveTemps = !Filename.empty();
1040
1041   size_t MaxTasks = Lto->getMaxTasks();
1042   std::vector<std::pair<SmallString<128>, bool>> Files(MaxTasks);
1043
1044   auto AddStream =
1045       [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
1046     Files[Task].second = !SaveTemps;
1047     int FD = getOutputFileName(Filename, /* TempOutFile */ !SaveTemps,
1048                                Files[Task].first, Task);
1049     return std::make_unique<lto::NativeObjectStream>(
1050         std::make_unique<llvm::raw_fd_ostream>(FD, true));
1051   };
1052
1053   auto AddBuffer = [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) {
1054     *AddStream(Task)->OS << MB->getBuffer();
1055   };
1056
1057   NativeObjectCache Cache;
1058   if (!options::cache_dir.empty())
1059     Cache = check(localCache(options::cache_dir, AddBuffer));
1060
1061   check(Lto->run(AddStream, Cache));
1062
1063   // Write empty output files that may be expected by the distributed build
1064   // system.
1065   if (options::thinlto_index_only)
1066     for (auto &Identifier : ObjectToIndexFileState)
1067       if (!Identifier.getValue())
1068         writeEmptyDistributedBuildOutputs(Identifier.getKey(), OldPrefix,
1069                                           NewPrefix, /* SkipModule */ false);
1070
1071   return Files;
1072 }
1073
1074 /// gold informs us that all symbols have been read. At this point, we use
1075 /// get_symbols to see if any of our definitions have been overridden by a
1076 /// native object file. Then, perform optimization and codegen.
1077 static ld_plugin_status allSymbolsReadHook() {
1078   if (Modules.empty())
1079     return LDPS_OK;
1080
1081   if (unsigned NumOpts = options::extra.size())
1082     cl::ParseCommandLineOptions(NumOpts, &options::extra[0]);
1083
1084   std::vector<std::pair<SmallString<128>, bool>> Files = runLTO();
1085
1086   if (options::TheOutputType == options::OT_DISABLE ||
1087       options::TheOutputType == options::OT_BC_ONLY ||
1088       options::TheOutputType == options::OT_ASM_ONLY)
1089     return LDPS_OK;
1090
1091   if (options::thinlto_index_only) {
1092     llvm_shutdown();
1093     cleanup_hook();
1094     exit(0);
1095   }
1096
1097   for (const auto &F : Files)
1098     if (!F.first.empty())
1099       recordFile(F.first.str(), F.second);
1100
1101   if (!options::extra_library_path.empty() &&
1102       set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK)
1103     message(LDPL_FATAL, "Unable to set the extra library path.");
1104
1105   return LDPS_OK;
1106 }
1107
1108 static ld_plugin_status all_symbols_read_hook(void) {
1109   ld_plugin_status Ret = allSymbolsReadHook();
1110   llvm_shutdown();
1111
1112   if (options::TheOutputType == options::OT_BC_ONLY ||
1113       options::TheOutputType == options::OT_ASM_ONLY ||
1114       options::TheOutputType == options::OT_DISABLE) {
1115     if (options::TheOutputType == options::OT_DISABLE) {
1116       // Remove the output file here since ld.bfd creates the output file
1117       // early.
1118       std::error_code EC = sys::fs::remove(output_name);
1119       if (EC)
1120         message(LDPL_ERROR, "Failed to delete '%s': %s", output_name.c_str(),
1121                 EC.message().c_str());
1122     }
1123     exit(0);
1124   }
1125
1126   return Ret;
1127 }
1128
1129 static ld_plugin_status cleanup_hook(void) {
1130   for (std::string &Name : Cleanup) {
1131     std::error_code EC = sys::fs::remove(Name);
1132     if (EC)
1133       message(LDPL_ERROR, "Failed to delete '%s': %s", Name.c_str(),
1134               EC.message().c_str());
1135   }
1136
1137   // Prune cache
1138   if (!options::cache_dir.empty()) {
1139     CachePruningPolicy policy = check(parseCachePruningPolicy(options::cache_policy));
1140     pruneCache(options::cache_dir, policy);
1141   }
1142
1143   return LDPS_OK;
1144 }