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