src/ld/passes/dylibs.cpp

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
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   3  * Copyright (c) 2010 Apple Inc. All rights reserved.
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  24
  25
  26 #include <stdint.h>
  27 #include <math.h>
  28 #include <unistd.h>
  29 #include <dlfcn.h>
  30 #include <mach/machine.h>
  31
  32 #include <vector>
  33
  34 #include "ld.hpp"
  35 #include "dylibs.h"
  36
  37 namespace ld {
  38 namespace passes {
  39 namespace dylibs {
  40
  41
  42 class WillBeUsed
  43 {
  44 public:
  45         bool operator()(ld::dylib::File* dylib) const {
  46                 return dylib->willRemoved();
  47         }
  48 };
  49
  50
  51 void doPass(const Options& opts, ld::Internal& state)
  52 {
  53 //      const bool log = false;
  54
  55         // only optimize dylibs in final linked images
  56         if ( opts.outputKind() == Options::kObjectFile )
  57                 return;
  58
  59         // clear "willRemoved" bit on all dylibs
  60         for (std::vector<ld::dylib::File*>::iterator it = state.dylibs.begin(); it != state.dylibs.end(); ++it) {
  61                 ld::dylib::File* aDylib = *it;
  62                 aDylib->setWillBeRemoved(false);
  63         }
  64         for (std::vector<ld::dylib::File*>::iterator it = state.dylibs.begin(); it != state.dylibs.end(); ++it) {
  65                 ld::dylib::File* aDylib = *it;
  66                 // set "willRemoved" bit on implicit dylibs that did not provide any exports
  67                 if ( aDylib->implicitlyLinked() && !aDylib->explicitlyLinked() && !aDylib->providedExportAtom() )
  68                         aDylib->setWillBeRemoved(true);
  69                 // set "willRemoved" bit on dead strippable explicit dylibs that did not provide any exports
  70                 if ( aDylib->explicitlyLinked() && aDylib->deadStrippable() && !aDylib->providedExportAtom() )
  71                         aDylib->setWillBeRemoved(true);
  72                 // set "willRemoved" bit on any unused explicit when -dead_strip_dylibs is used
  73                 if ( opts.deadStripDylibs() && !aDylib->providedExportAtom() )
  74                         aDylib->setWillBeRemoved(true);
  75         }
  76
  77
  78         // remove unused dylibs
  79         state.dylibs.erase(std::remove_if(state.dylibs.begin(), state.dylibs.end(), WillBeUsed()), state.dylibs.end());
  80
  81 }
  82
  83
  84 } // namespace dylibs
  85 } // namespace passes
  86 } // namespace ld