ld64-134.9/src/ld/ld.cpp

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-*
   2  *
   3  * Copyright (c) 2005-2011 Apple Inc. All rights reserved.
   4  *
   5  * @APPLE_LICENSE_HEADER_START@
   6  *
   7  * This file contains Original Code and/or Modifications of Original Code
   8  * as defined in and that are subject to the Apple Public Source License
   9  * Version 2.0 (the 'License'). You may not use this file except in
  10  * compliance with the License. Please obtain a copy of the License at
  11  * http://www.opensource.apple.com/apsl/ and read it before using this
  12  * file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  19  * Please see the License for the specific language governing rights and
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  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24
  25 // start temp HACK for cross builds
  26 extern "C" double log2 ( double );
  27 //#define __MATH__
  28 // end temp HACK for cross builds
  29
  30
  31 #include <stdlib.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/mman.h>
  35 #include <sys/sysctl.h>
  36 #include <fcntl.h>
  37 #include <errno.h>
  38 #include <limits.h>
  39 #include <unistd.h>
  40 #include <execinfo.h>
  41 #include <mach/mach_time.h>
  42 #include <mach/vm_statistics.h>
  43 #include <mach/mach_init.h>
  44 #include <mach/mach_host.h>
  45 #include <dlfcn.h>
  46 #include <mach-o/dyld.h>
  47 #include <dlfcn.h>
  48 #include <AvailabilityMacros.h>
  49
  50 #include <string>
  51 #include <map>
  52 #include <set>
  53 #include <string>
  54 #include <vector>
  55 #include <list>
  56 #include <algorithm>
  57 #include <ext/hash_map>
  58 #include <ext/hash_set>
  59 #include <cxxabi.h>
  60
  61 #include "Options.h"
  62
  63 #include "MachOFileAbstraction.hpp"
  64 #include "Architectures.hpp"
  65 #include "ld.hpp"
  66
  67 #include "InputFiles.h"
  68 #include "Resolver.h"
  69 #include "OutputFile.h"
  70 #include "Snapshot.h"
  71
  72 #include "passes/stubs/make_stubs.h"
  73 #include "passes/dtrace_dof.h"
  74 #include "passes/got.h"
  75 #include "passes/tlvp.h"
  76 #include "passes/huge.h"
  77 #include "passes/compact_unwind.h"
  78 #include "passes/order.h"
  79 #include "passes/branch_island.h"
  80 #include "passes/branch_shim.h"
  81 #include "passes/objc.h"
  82 #include "passes/dylibs.h"
  83
  84 #include "parsers/archive_file.h"
  85 #include "parsers/macho_relocatable_file.h"
  86 #include "parsers/macho_dylib_file.h"
  87 #include "parsers/lto_file.h"
  88 #include "parsers/opaque_section_file.h"
  89
  90
  91 struct PerformanceStatistics {
  92         uint64_t                                                startTool;
  93         uint64_t                                                startInputFileProcessing;
  94         uint64_t                                                startResolver;
  95         uint64_t                                                startDylibs;
  96         uint64_t                                                startPasses;
  97         uint64_t                                                startOutput;
  98         uint64_t                                                startDone;
  99         vm_statistics_data_t                    vmStart;
 100         vm_statistics_data_t                    vmEnd;
 101 };
 102
 103
 104
 105
 106
 107 class InternalState : public ld::Internal
 108 {
 109 public:
 110                                                                                         InternalState(const Options& opts) : _options(opts), _atomsOrderedInSections(false) { }
 111         virtual ld::Internal::FinalSection*             addAtom(const ld::Atom& atom);
 112         virtual ld::Internal::FinalSection*             getFinalSection(const ld::Section&);
 113
 114         void                                                                    sortSections();
 115         void                                                                    markAtomsOrdered() { _atomsOrderedInSections = true; }
 116         virtual                                                                 ~InternalState() {}
 117 private:
 118
 119         class FinalSection : public ld::Internal::FinalSection
 120         {
 121         public:
 122                                                         FinalSection(const ld::Section& sect, uint32_t sectionsSeen, bool objFile);
 123                 static int                                      sectionComparer(const void* l, const void* r);
 124                 static const ld::Section&       outputSection(const ld::Section& sect, bool mergeZeroFill);
 125                 static const ld::Section&       objectOutputSection(const ld::Section& sect, bool makeTentativeDefsReal);
 126         private:
 127                 friend class InternalState;
 128                 static uint32_t         sectionOrder(const ld::Section& sect, uint32_t sectionsSeen);
 129                 static uint32_t         segmentOrder(const ld::Section& sect, bool objFile);
 130                 uint32_t                        _segmentOrder;
 131                 uint32_t                        _sectionOrder;
 132
 133                 static std::vector<const char*> _s_segmentsSeen;
 134                 static ld::Section              _s_DATA_data;
 135                 static ld::Section              _s_DATA_const;
 136                 static ld::Section              _s_TEXT_text;
 137                 static ld::Section              _s_TEXT_const;
 138                 static ld::Section              _s_DATA_nl_symbol_ptr;
 139                 static ld::Section              _s_DATA_common;
 140                 static ld::Section              _s_DATA_zerofill;
 141         };
 142
 143
 144         struct SectionHash {
 145                 size_t operator()(const ld::Section*) const;
 146         };
 147         struct SectionEquals {
 148                 bool operator()(const ld::Section* left, const ld::Section* right) const;
 149         };
 150         typedef __gnu_cxx::hash_map<const ld::Section*, FinalSection*, SectionHash, SectionEquals> SectionInToOut;
 151
 152
 153         SectionInToOut                  _sectionInToFinalMap;
 154         const Options&                  _options;
 155         bool                                    _atomsOrderedInSections;
 156 };
 157
 158 ld::Section     InternalState::FinalSection::_s_DATA_data( "__DATA", "__data",  ld::Section::typeUnclassified);
 159 ld::Section     InternalState::FinalSection::_s_DATA_const("__DATA", "__const", ld::Section::typeUnclassified);
 160 ld::Section     InternalState::FinalSection::_s_TEXT_text( "__TEXT", "__text",  ld::Section::typeCode);
 161 ld::Section     InternalState::FinalSection::_s_TEXT_const("__TEXT", "__const", ld::Section::typeUnclassified);
 162 ld::Section     InternalState::FinalSection::_s_DATA_nl_symbol_ptr("__DATA", "__nl_symbol_ptr", ld::Section::typeNonLazyPointer);
 163 ld::Section     InternalState::FinalSection::_s_DATA_common("__DATA", "__common", ld::Section::typeZeroFill);
 164 ld::Section     InternalState::FinalSection::_s_DATA_zerofill("__DATA", "__zerofill", ld::Section::typeZeroFill);
 165 std::vector<const char*> InternalState::FinalSection::_s_segmentsSeen;
 166
 167
 168 size_t InternalState::SectionHash::operator()(const ld::Section* sect) const
 169 {
 170         size_t hash = 0;
 171         __gnu_cxx::hash<const char*> temp;
 172         hash += temp.operator()(sect->segmentName());
 173         hash += temp.operator()(sect->sectionName());
 174         return hash;
 175 }
 176
 177 bool InternalState::SectionEquals::operator()(const ld::Section* left, const ld::Section* right) const
 178 {
 179         return (*left == *right);
 180 }
 181
 182
 183 InternalState::FinalSection::FinalSection(const ld::Section& sect, uint32_t sectionsSeen, bool objFile)
 184         : ld::Internal::FinalSection(sect),
 185           _segmentOrder(segmentOrder(sect, objFile)),
 186           _sectionOrder(sectionOrder(sect, sectionsSeen))
 187 {
 188         //fprintf(stderr, "FinalSection(%s, %s) _segmentOrder=%d, _sectionOrder=%d\n",
 189         //              this->segmentName(), this->sectionName(), _segmentOrder, _sectionOrder);
 190 }
 191
 192 const ld::Section& InternalState::FinalSection::outputSection(const ld::Section& sect, bool mergeZeroFill)
 193 {
 194         // merge sections in final linked image
 195         switch ( sect.type() ) {
 196                 case ld::Section::typeLiteral4:
 197                 case ld::Section::typeLiteral8:
 198                 case ld::Section::typeLiteral16:
 199                         return _s_TEXT_const;
 200                 case ld::Section::typeUnclassified:
 201                         if ( strcmp(sect.segmentName(), "__DATA") == 0 ) {
 202                                 if ( strcmp(sect.sectionName(), "__datacoal_nt") == 0 )
 203                                         return _s_DATA_data;
 204                                 if ( strcmp(sect.sectionName(), "__const_coal") == 0 )
 205                                         return _s_DATA_const;
 206                         }
 207                         else if ( strcmp(sect.segmentName(), "__TEXT") == 0 ) {
 208                                 if ( strcmp(sect.sectionName(), "__const_coal") == 0 )
 209                                         return _s_TEXT_const;
 210                         }
 211                         break;
 212                 case ld::Section::typeZeroFill:
 213                         if ( mergeZeroFill )
 214                                 return _s_DATA_zerofill;
 215                         break;
 216                 case ld::Section::typeCode:
 217                         if ( strcmp(sect.segmentName(), "__TEXT") == 0 ) {
 218                                 if ( strcmp(sect.sectionName(), "__textcoal_nt") == 0 )
 219                                         return _s_TEXT_text;
 220                                 else if ( strcmp(sect.sectionName(), "__StaticInit") == 0 )
 221                                         return _s_TEXT_text;
 222                         }
 223                         break;
 224                 case ld::Section::typeNonLazyPointer:
 225                         if ( strcmp(sect.segmentName(), "__DATA") == 0 ) {
 226                                 if ( strcmp(sect.sectionName(), "__nl_symbol_ptr") == 0 )
 227                                         return _s_DATA_nl_symbol_ptr;
 228                         }
 229                         else if ( strcmp(sect.segmentName(), "__IMPORT") == 0 ) {
 230                                 if ( strcmp(sect.sectionName(), "__pointers") == 0 )
 231                                         return _s_DATA_nl_symbol_ptr;
 232                         }
 233                         break;
 234                 case ld::Section::typeTentativeDefs:
 235                         if ( mergeZeroFill )
 236                                 return _s_DATA_zerofill;
 237                         else
 238                                 return _s_DATA_common;
 239                         break;
 240                         // FIX ME: more
 241                 default:
 242                         break;
 243         }
 244         return sect;
 245 }
 246
 247 const ld::Section& InternalState::FinalSection::objectOutputSection(const ld::Section& sect, bool makeTentativeDefsReal)
 248 {
 249         // in -r mode the only section that ever changes is __tenative -> __common with -d option
 250         if ( (sect.type() == ld::Section::typeTentativeDefs) && makeTentativeDefsReal)
 251                 return _s_DATA_common;
 252         return sect;
 253 }
 254
 255 uint32_t InternalState::FinalSection::segmentOrder(const ld::Section& sect, bool objFile)
 256 {
 257         if ( strcmp(sect.segmentName(), "__PAGEZERO") == 0 )
 258                 return 0;
 259         if ( strcmp(sect.segmentName(), "__HEADER") == 0 ) // only used with -preload
 260                 return 0;
 261         if ( strcmp(sect.segmentName(), "__TEXT") == 0 )
 262                 return 1;
 263         // in -r mode, want __DATA  last so zerofill sections are at end
 264         if ( strcmp(sect.segmentName(), "__DATA") == 0 )
 265                 return (objFile ? 5 : 2);
 266         if ( strcmp(sect.segmentName(), "__OBJC") == 0 )
 267                 return 3;
 268         if ( strcmp(sect.segmentName(), "__IMPORT") == 0 )
 269                 return 4;
 270
 271         // layout non-standard segments in order seen (+10 to shift beyond standard segments)
 272         for (uint32_t i=0; i < _s_segmentsSeen.size(); ++i) {
 273                 if ( strcmp(_s_segmentsSeen[i], sect.segmentName()) == 0 )
 274                         return i+10;
 275         }
 276         _s_segmentsSeen.push_back(sect.segmentName());
 277         return _s_segmentsSeen.size()-1+10;
 278 }
 279
 280 uint32_t InternalState::FinalSection::sectionOrder(const ld::Section& sect, uint32_t sectionsSeen)
 281 {
 282         if ( sect.type() == ld::Section::typeFirstSection )
 283                 return 0;
 284         if ( sect.type() == ld::Section::typeMachHeader )
 285                 return 1;
 286         if ( sect.type() == ld::Section::typeLastSection )
 287                 return INT_MAX;
 288         if ( strcmp(sect.segmentName(), "__TEXT") == 0 ) {
 289                 switch ( sect.type() ) {
 290                         case ld::Section::typeCode:
 291                                 // <rdar://problem/8346444> make __text always be first "code" section
 292                                 if ( strcmp(sect.sectionName(), "__text") == 0 )
 293                                         return 10;
 294                                 else
 295                                         return 11;
 296                         case ld::Section::typeStub:
 297                                 return 12;
 298                         case ld::Section::typeStubHelper:
 299                                 return 13;
 300                         case ld::Section::typeLSDA:
 301                                 return INT_MAX-3;
 302                         case ld::Section::typeUnwindInfo:
 303                                 return INT_MAX-2;
 304                         case ld::Section::typeCFI:
 305                                 return INT_MAX-1;
 306                         case ld::Section::typeStubClose:
 307                                 return INT_MAX;
 308                         default:
 309                                 return sectionsSeen+20;
 310                 }
 311         }
 312         else if ( strcmp(sect.segmentName(), "__DATA") == 0 ) {
 313                 switch ( sect.type() ) {
 314                         case ld::Section::typeLazyPointerClose:
 315                                 return 8;
 316                         case ld::Section::typeDyldInfo:
 317                                 return 9;
 318                         case ld::Section::typeNonLazyPointer:
 319                                 return 10;
 320                         case ld::Section::typeLazyPointer:
 321                                 return 11;
 322                         case ld::Section::typeInitializerPointers:
 323                                 return 12;
 324                         case ld::Section::typeTerminatorPointers:
 325                                 return 13;
 326                         case ld::Section::typeTLVInitialValues:
 327                                 return INT_MAX-4; // need TLV zero-fill to follow TLV init values
 328                         case ld::Section::typeTLVZeroFill:
 329                                 return INT_MAX-3;
 330                         case ld::Section::typeZeroFill:
 331                                 // make sure __huge is always last zerofill section
 332                                 if ( strcmp(sect.sectionName(), "__huge") == 0 )
 333                                         return INT_MAX-1;
 334                                 else
 335                                         return INT_MAX-2;
 336                         default:
 337                                 // <rdar://problem/7435296> Reorder sections to reduce page faults in object files
 338                                 if ( strcmp(sect.sectionName(), "__objc_classlist") == 0 )
 339                                         return 20;
 340                                 else if ( strcmp(sect.sectionName(), "__objc_nlclslist") == 0 )
 341                                         return 21;
 342                                 else if ( strcmp(sect.sectionName(), "__objc_catlist") == 0 )
 343                                         return 22;
 344                                 else if ( strcmp(sect.sectionName(), "__objc_protolist") == 0 )
 345                                         return 23;
 346                                 else if ( strcmp(sect.sectionName(), "__objc_imageinfo") == 0 )
 347                                         return 24;
 348                                 else if ( strcmp(sect.sectionName(), "__objc_const") == 0 )
 349                                         return 25;
 350                                 else if ( strcmp(sect.sectionName(), "__objc_selrefs") == 0 )
 351                                         return 26;
 352                                 else if ( strcmp(sect.sectionName(), "__objc_msgrefs") == 0 )
 353                                         return 27;
 354                                 else if ( strcmp(sect.sectionName(), "__objc_protorefs") == 0 )
 355                                         return 28;
 356                                 else if ( strcmp(sect.sectionName(), "__objc_classrefs") == 0 )
 357                                         return 29;
 358                                 else if ( strcmp(sect.sectionName(), "__objc_superrefs") == 0 )
 359                                         return 30;
 360                                 else if ( strcmp(sect.sectionName(), "__objc_data") == 0 )
 361                                         return 31;
 362                                 else
 363                                         return sectionsSeen+40;
 364                 }
 365         }
 366         // make sure zerofill in any other section is at end of segment
 367         if ( sect.type() == ld::Section::typeZeroFill )
 368                 return INT_MAX-1;
 369         return sectionsSeen+20;
 370 }
 371
 372 #ifndef NDEBUG
 373 static void validateFixups(const ld::Atom& atom)
 374 {
 375         //fprintf(stderr, "validateFixups %s\n", atom.name());
 376         bool lastWasClusterEnd = true;
 377         ld::Fixup::Cluster lastClusterSize = ld::Fixup::k1of1;
 378         uint32_t curClusterOffsetInAtom = 0;
 379         for (ld::Fixup::iterator fit=atom.fixupsBegin(); fit != atom.fixupsEnd(); ++fit) {
 380                 //fprintf(stderr, "  fixup offset=%d, cluster=%d\n", fit->offsetInAtom, fit->clusterSize);
 381                 assert((fit->offsetInAtom <= atom.size()) || (fit->offsetInAtom == 0));
 382                 if ( fit->firstInCluster() ) {
 383                         assert(lastWasClusterEnd);
 384                         curClusterOffsetInAtom = fit->offsetInAtom;
 385                         lastWasClusterEnd = (fit->clusterSize == ld::Fixup::k1of1);
 386                 }
 387                 else {
 388                         assert(!lastWasClusterEnd);
 389                         assert(fit->offsetInAtom == curClusterOffsetInAtom);
 390                         switch ((ld::Fixup::Cluster)fit->clusterSize) {
 391                                 case ld::Fixup::k1of1:
 392                                 case ld::Fixup::k1of2:
 393                                 case ld::Fixup::k1of3:
 394                                 case ld::Fixup::k1of4:
 395                                 case ld::Fixup::k1of5:
 396                                         lastWasClusterEnd = false;
 397                                         break;
 398                                 case ld::Fixup::k2of2:
 399                                         assert(lastClusterSize = ld::Fixup::k1of2);
 400                                         lastWasClusterEnd = true;
 401                                         break;
 402                                 case ld::Fixup::k2of3:
 403                                         assert(lastClusterSize = ld::Fixup::k1of3);
 404                                         lastWasClusterEnd = false;
 405                                         break;
 406                                 case ld::Fixup::k2of4:
 407                                         assert(lastClusterSize = ld::Fixup::k1of4);
 408                                         lastWasClusterEnd = false;
 409                                         break;
 410                                 case ld::Fixup::k2of5:
 411                                         assert(lastClusterSize = ld::Fixup::k1of5);
 412                                         lastWasClusterEnd = false;
 413                                         break;
 414                                 case ld::Fixup::k3of3:
 415                                         assert(lastClusterSize = ld::Fixup::k2of3);
 416                                         lastWasClusterEnd = true;
 417                                         break;
 418                                 case ld::Fixup::k3of4:
 419                                         assert(lastClusterSize = ld::Fixup::k2of4);
 420                                         lastWasClusterEnd = false;
 421                                         break;
 422                                 case ld::Fixup::k3of5:
 423                                         assert(lastClusterSize = ld::Fixup::k2of5);
 424                                         lastWasClusterEnd = false;
 425                                         break;
 426                                 case ld::Fixup::k4of4:
 427                                         assert(lastClusterSize = ld::Fixup::k3of4);
 428                                         lastWasClusterEnd = true;
 429                                         break;
 430                                 case ld::Fixup::k4of5:
 431                                         assert(lastClusterSize = ld::Fixup::k3of5);
 432                                         lastWasClusterEnd = false;
 433                                         break;
 434                                 case ld::Fixup::k5of5:
 435                                         assert(lastClusterSize = ld::Fixup::k4of5);
 436                                         lastWasClusterEnd = true;
 437                                         break;
 438                         }
 439                 }
 440                 lastClusterSize = fit->clusterSize;
 441                 if ( fit->binding == ld::Fixup::bindingDirectlyBound ) {
 442                         assert(fit->u.target != NULL);
 443                 }
 444         }
 445         switch (lastClusterSize) {
 446                 case ld::Fixup::k1of1:
 447                 case ld::Fixup::k2of2:
 448                 case ld::Fixup::k3of3:
 449                 case ld::Fixup::k4of4:
 450                 case ld::Fixup::k5of5:
 451                         break;
 452                 default:
 453                         assert(0 && "last fixup was not end of cluster");
 454                         break;
 455         }
 456 }
 457 #endif
 458
 459 ld::Internal::FinalSection* InternalState::addAtom(const ld::Atom& atom)
 460 {
 461         ld::Internal::FinalSection* fs = this->getFinalSection(atom.section());
 462         //fprintf(stderr, "InternalState::doAtom(%p), name=%s, sect=%s, finalsect=%p\n", &atom, atom.name(), atom.section().sectionName(), fs);
 463 #ifndef NDEBUG
 464         validateFixups(atom);
 465 #endif
 466         if ( _atomsOrderedInSections ) {
 467                 // make sure this atom is placed before any trailing section$end$ atom
 468                 if ( (fs->atoms.size() > 1) && (fs->atoms.back()->contentType() == ld::Atom::typeSectionEnd) ) {
 469                         // last atom in section$end$ atom, insert before it
 470                         const ld::Atom* endAtom = fs->atoms.back();
 471                         fs->atoms.pop_back();
 472                         fs->atoms.push_back(&atom);
 473                         fs->atoms.push_back(endAtom);
 474                 }
 475                 else {
 476                         // not end atom, just append new atom
 477                         fs->atoms.push_back(&atom);
 478                 }
 479         }
 480         else {
 481                 // normal case
 482                 fs->atoms.push_back(&atom);
 483         }
 484         return fs;
 485 }
 486
 487 ld::Internal::FinalSection* InternalState::getFinalSection(const ld::Section& inputSection)
 488 {
 489         const ld::Section* baseForFinalSection = &inputSection;
 490
 491         // see if input section already has a FinalSection
 492         SectionInToOut::iterator pos = _sectionInToFinalMap.find(&inputSection);
 493         if ( pos != _sectionInToFinalMap.end() ) {
 494                 return pos->second;
 495         }
 496
 497         // otherwise, create a new final section
 498         bool objFile = false;
 499         switch ( _options.outputKind() ) {
 500                 case Options::kStaticExecutable:
 501                 case Options::kDynamicExecutable:
 502                 case Options::kDynamicLibrary:
 503                 case Options::kDynamicBundle:
 504                 case Options::kDyld:
 505                 case Options::kKextBundle:
 506                 case Options::kPreload:
 507                         {
 508                                 // coalesce some sections
 509                                 const ld::Section& outSect = FinalSection::outputSection(inputSection, _options.mergeZeroFill());
 510                                 pos = _sectionInToFinalMap.find(&outSect);
 511                                 if ( pos != _sectionInToFinalMap.end() ) {
 512                                         _sectionInToFinalMap[&inputSection] = pos->second;
 513                                         //fprintf(stderr, "_sectionInToFinalMap[%p] = %p\n", &inputSection, pos->second);
 514                                         return pos->second;
 515                                 }
 516                                 else if ( outSect != inputSection ) {
 517                                         // new output section created, but not in map
 518                                         baseForFinalSection = &outSect;
 519                                 }
 520                         }
 521                         break;
 522                 case Options::kObjectFile:
 523                         baseForFinalSection = &FinalSection::objectOutputSection(inputSection, _options.makeTentativeDefinitionsReal());
 524                         pos = _sectionInToFinalMap.find(baseForFinalSection);
 525                         if ( pos != _sectionInToFinalMap.end() ) {
 526                                 _sectionInToFinalMap[&inputSection] = pos->second;
 527                                 //fprintf(stderr, "_sectionInToFinalMap[%p] = %p\n", &inputSection, pos->second);
 528                                 return pos->second;
 529                         }
 530                         objFile = true;
 531                         break;
 532         }
 533
 534         InternalState::FinalSection* result = new InternalState::FinalSection(*baseForFinalSection,
 535                                                                                                                                         _sectionInToFinalMap.size(), objFile);
 536         _sectionInToFinalMap[baseForFinalSection] = result;
 537         //fprintf(stderr, "_sectionInToFinalMap[%p] = %p\n", baseForFinalSection, result);
 538         sections.push_back(result);
 539         return result;
 540 }
 541
 542
 543 int InternalState::FinalSection::sectionComparer(const void* l, const void* r)
 544 {
 545         const FinalSection* left  = *(FinalSection**)l;
 546         const FinalSection* right = *(FinalSection**)r;
 547         if ( left->_segmentOrder != right->_segmentOrder )
 548                 return (left->_segmentOrder - right->_segmentOrder);
 549         return (left->_sectionOrder - right->_sectionOrder);
 550 }
 551
 552 void InternalState::sortSections()
 553 {
 554         //fprintf(stderr, "UNSORTED final sections:\n");
 555         //for (std::vector<ld::Internal::FinalSection*>::iterator it = sections.begin(); it != sections.end(); ++it) {
 556         //      fprintf(stderr, "final section %p %s/%s\n", (*it), (*it)->segmentName(), (*it)->sectionName());
 557         //}
 558         qsort(&sections[0], sections.size(), sizeof(FinalSection*), &InternalState::FinalSection::sectionComparer);
 559         //fprintf(stderr, "SORTED final sections:\n");
 560         //for (std::vector<ld::Internal::FinalSection*>::iterator it = sections.begin(); it != sections.end(); ++it) {
 561         //      fprintf(stderr, "final section %p %s/%s\n", (*it), (*it)->segmentName(), (*it)->sectionName());
 562         //}
 563         assert((sections[0]->type() == ld::Section::typeMachHeader)
 564                 || ((sections[0]->type() == ld::Section::typeFirstSection) && (sections[1]->type() == ld::Section::typeMachHeader))
 565                 || ((sections[0]->type() == ld::Section::typePageZero) && (sections[1]->type() == ld::Section::typeMachHeader))
 566                 || ((sections[0]->type() == ld::Section::typePageZero) && (sections[1]->type() == ld::Section::typeFirstSection) && (sections[2]->type() == ld::Section::typeMachHeader)) );
 567
 568 }
 569
 570 static char* commatize(uint64_t in, char* out)
 571 {
 572         char* result = out;
 573         char rawNum[30];
 574         sprintf(rawNum, "%llu", in);
 575         const int rawNumLen = strlen(rawNum);
 576         for(int i=0; i < rawNumLen-1; ++i) {
 577                 *out++ = rawNum[i];
 578                 if ( ((rawNumLen-i) % 3) == 1 )
 579                         *out++ = ',';
 580         }
 581         *out++ = rawNum[rawNumLen-1];
 582         *out = '\0';
 583         return result;
 584 }
 585
 586 static void printTime(const char* msg, uint64_t partTime, uint64_t totalTime)
 587 {
 588         static uint64_t sUnitsPerSecond = 0;
 589         if ( sUnitsPerSecond == 0 ) {
 590                 struct mach_timebase_info timeBaseInfo;
 591                 if ( mach_timebase_info(&timeBaseInfo) == KERN_SUCCESS ) {
 592                         sUnitsPerSecond = 1000000000ULL * timeBaseInfo.denom / timeBaseInfo.numer;
 593                         //fprintf(stderr, "sUnitsPerSecond=%llu\n", sUnitsPerSecond);
 594                 }
 595         }
 596         if ( partTime < sUnitsPerSecond ) {
 597                 uint32_t milliSecondsTimeTen = (partTime*10000)/sUnitsPerSecond;
 598                 uint32_t milliSeconds = milliSecondsTimeTen/10;
 599                 uint32_t percentTimesTen = (partTime*1000)/totalTime;
 600                 uint32_t percent = percentTimesTen/10;
 601                 fprintf(stderr, "%24s: % 4d.%d milliseconds (% 4d.%d%%)\n", msg, milliSeconds, milliSecondsTimeTen-milliSeconds*10, percent, percentTimesTen-percent*10);
 602         }
 603         else {
 604                 uint32_t secondsTimeTen = (partTime*10)/sUnitsPerSecond;
 605                 uint32_t seconds = secondsTimeTen/10;
 606                 uint32_t percentTimesTen = (partTime*1000)/totalTime;
 607                 uint32_t percent = percentTimesTen/10;
 608                 fprintf(stderr, "%24s: % 4d.%d seconds (% 4d.%d%%)\n", msg, seconds, secondsTimeTen-seconds*10, percent, percentTimesTen-percent*10);
 609         }
 610 }
 611
 612
 613 static void getVMInfo(vm_statistics_data_t& info)
 614 {
 615         mach_msg_type_number_t count = sizeof(vm_statistics_data_t) / sizeof(natural_t);
 616         kern_return_t error = host_statistics(mach_host_self(), HOST_VM_INFO,
 617                                                         (host_info_t)&info, &count);
 618         if (error != KERN_SUCCESS) {
 619                 bzero(&info, sizeof(vm_statistics_data_t));
 620         }
 621 }
 622
 623
 624
 625 static const char* sOverridePathlibLTO = NULL;
 626
 627 //
 628 // This is magic glue that overrides the default behaviour
 629 // of lazydylib1.o which is used to lazily load libLTO.dylib.
 630 //
 631 extern "C" const char* dyld_lazy_dylib_path_fix(const char* path);
 632 const char* dyld_lazy_dylib_path_fix(const char* path)
 633 {
 634         if ( sOverridePathlibLTO != NULL )
 635                 return sOverridePathlibLTO;
 636         else
 637                 return path;
 638 }
 639
 640
 641
 642 int main(int argc, const char* argv[])
 643 {
 644         const char* archName = NULL;
 645         bool showArch = false;
 646         bool archInferred = false;
 647         try {
 648                 PerformanceStatistics statistics;
 649                 statistics.startTool = mach_absolute_time();
 650
 651                 // create object to track command line arguments
 652                 Options options(argc, argv);
 653                 InternalState state(options);
 654
 655                 // allow libLTO to be overridden by command line -lto_library
 656                 sOverridePathlibLTO = options.overridePathlibLTO();
 657
 658                 // gather vm stats
 659                 if ( options.printStatistics() )
 660                         getVMInfo(statistics.vmStart);
 661
 662                 // update strings for error messages
 663                 showArch = options.printArchPrefix();
 664                 archName = options.architectureName();
 665                 archInferred = (options.architecture() == 0);
 666
 667                 // open and parse input files
 668                 statistics.startInputFileProcessing = mach_absolute_time();
 669                 ld::tool::InputFiles inputFiles(options, &archName);
 670
 671                 // load and resolve all references
 672                 statistics.startResolver = mach_absolute_time();
 673                 ld::tool::Resolver resolver(options, inputFiles, state);
 674                 resolver.resolve();
 675
 676                 // add dylibs used
 677                 statistics.startDylibs = mach_absolute_time();
 678                 inputFiles.dylibs(state);
 679
 680                 // do initial section sorting so passes have rough idea of the layout
 681                 state.sortSections();
 682
 683                 // run passes
 684                 statistics.startPasses = mach_absolute_time();
 685                 ld::passes::objc::doPass(options, state);
 686                 ld::passes::stubs::doPass(options, state);
 687                 ld::passes::huge::doPass(options, state);
 688                 ld::passes::got::doPass(options, state);
 689                 ld::passes::tlvp::doPass(options, state);
 690                 ld::passes::dylibs::doPass(options, state);     // must be after stubs and GOT passes
 691                 ld::passes::order::doPass(options, state);
 692                 state.markAtomsOrdered();
 693                 ld::passes::branch_shim::doPass(options, state);        // must be after stubs
 694                 ld::passes::branch_island::doPass(options, state);      // must be after stubs and order pass
 695                 ld::passes::dtrace::doPass(options, state);
 696                 ld::passes::compact_unwind::doPass(options, state);  // must be after order pass
 697
 698                 // sort final sections
 699                 state.sortSections();
 700
 701                 // write output file
 702                 statistics.startOutput = mach_absolute_time();
 703                 ld::tool::OutputFile out(options);
 704                 out.write(state);
 705                 statistics.startDone = mach_absolute_time();
 706
 707                 // print statistics
 708                 //mach_o::relocatable::printCounts();
 709                 if ( options.printStatistics() ) {
 710                         getVMInfo(statistics.vmEnd);
 711                         uint64_t totalTime = statistics.startDone - statistics.startTool;
 712                         printTime("ld total time", totalTime, totalTime);
 713                         printTime(" option parsing time", statistics.startInputFileProcessing  -        statistics.startTool,                           totalTime);
 714                         printTime(" object file processing", statistics.startResolver                    -      statistics.startInputFileProcessing,totalTime);
 715                         printTime(" resolve symbols", statistics.startDylibs                             -      statistics.startResolver,                       totalTime);
 716                         printTime(" build atom list", statistics.startPasses                             -      statistics.startDylibs,                         totalTime);
 717                         printTime(" passess", statistics.startOutput                             -      statistics.startPasses,                         totalTime);
 718                         printTime(" write output", statistics.startDone                          -      statistics.startOutput,                         totalTime);
 719                         fprintf(stderr, "pageins=%u, pageouts=%u, faults=%u\n",
 720                                                                 statistics.vmEnd.pageins-statistics.vmStart.pageins,
 721                                                                 statistics.vmEnd.pageouts-statistics.vmStart.pageouts,
 722                                                                 statistics.vmEnd.faults-statistics.vmStart.faults);
 723                         char temp[40];
 724                         fprintf(stderr, "processed %3u object files,  totaling %15s bytes\n", inputFiles._totalObjectLoaded, commatize(inputFiles._totalObjectSize, temp));
 725                         fprintf(stderr, "processed %3u archive files, totaling %15s bytes\n", inputFiles._totalArchivesLoaded, commatize(inputFiles._totalArchiveSize, temp));
 726                         fprintf(stderr, "processed %3u dylib files\n", inputFiles._totalDylibsLoaded);
 727                         fprintf(stderr, "wrote output file            totaling %15s bytes\n", commatize(out.fileSize(), temp));
 728                 }
 729                 // <rdar://problem/6780050> Would like linker warning to be build error.
 730                 if ( options.errorBecauseOfWarnings() ) {
 731                         fprintf(stderr, "ld: fatal warning(s) induced error (-fatal_warnings)\n");
 732                         return 1;
 733                 }
 734         }
 735         catch (const char* msg) {
 736                 if ( archInferred )
 737                         fprintf(stderr, "ld: %s for inferred architecture %s\n", msg, archName);
 738                 else if ( showArch )
 739                         fprintf(stderr, "ld: %s for architecture %s\n", msg, archName);
 740                 else
 741                         fprintf(stderr, "ld: %s\n", msg);
 742                 return 1;
 743         }
 744
 745         return 0;
 746 }
 747
 748
 749 #ifndef NDEBUG
 750 // implement assert() function to print out a backtrace before aborting
 751 void __assert_rtn(const char* func, const char* file, int line, const char* failedexpr)
 752 {
 753     Snapshot *snapshot = Snapshot::globalSnapshot;
 754
 755     snapshot->setSnapshotMode(Snapshot::SNAPSHOT_DEBUG);
 756     snapshot->createSnapshot();
 757         snapshot->recordAssertionMessage("Assertion failed: (%s), function %s, file %s, line %d.\n", failedexpr, func, file, line);
 758
 759         void* callStack[128];
 760         int depth = ::backtrace(callStack, 128);
 761         char* buffer = (char*)malloc(1024);
 762         for(int i=0; i < depth-1; ++i) {
 763                 Dl_info info;
 764                 dladdr(callStack[i], &info);
 765                 const char* symboName = info.dli_sname;
 766                 if ( (symboName != NULL) && (strncmp(symboName, "_Z", 2) == 0) ) {
 767                         size_t bufLen = 1024;
 768                         int result;
 769                         char* unmangled = abi::__cxa_demangle(symboName, buffer, &bufLen, &result);
 770                         if ( unmangled != NULL )
 771                                 symboName = unmangled;
 772                 }
 773                 long offset = (uintptr_t)callStack[i] - (uintptr_t)info.dli_saddr;
 774                 fprintf(stderr, "%d  %p  %s + %ld\n", i, callStack[i], symboName, offset);
 775                 snapshot->recordAssertionMessage("%d  %p  %s + %ld\n", i, callStack[i], symboName, offset);
 776         }
 777     fprintf(stderr, "A linker snapshot was created at:\n\t%s\n", snapshot->rootDir());
 778         fprintf(stderr, "ld: Assertion failed: (%s), function %s, file %s, line %d.\n", failedexpr, func, file, line);
 779         exit(1);
 780 }
 781 #endif
 782
 783