lld/MachO/Symbols.cpp

   1 //===- Symbols.cpp --------------------------------------------------------===//
   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 #include "Symbols.h"
  10 #include "InputFiles.h"
  11 #include "SyntheticSections.h"
  12 #include "lld/Common/Strings.h"
  13
  14 using namespace llvm;
  15 using namespace lld;
  16 using namespace lld::macho;
  17
  18 static_assert(sizeof(void *) != 8 || sizeof(Symbol) == 56,
  19               "Try to minimize Symbol's size; we create many instances");
  20
  21 // The Microsoft ABI doesn't support using parent class tail padding for child
  22 // members, hence the _MSC_VER check.
  23 #if !defined(_MSC_VER)
  24 static_assert(sizeof(void *) != 8 || sizeof(Defined) == 88,
  25               "Try to minimize Defined's size; we create many instances");
  26 #endif
  27
  28 static_assert(sizeof(SymbolUnion) == sizeof(Defined),
  29               "Defined should be the largest Symbol kind");
  30
  31 std::string lld::toString(const Symbol &sym) {
  32   return demangle(sym.getName(), config->demangle);
  33 }
  34
  35 std::string lld::toMachOString(const object::Archive::Symbol &b) {
  36   return demangle(b.getName(), config->demangle);
  37 }
  38
  39 uint64_t Symbol::getStubVA() const { return in.stubs->getVA(stubsIndex); }
  40 uint64_t Symbol::getGotVA() const { return in.got->getVA(gotIndex); }
  41 uint64_t Symbol::getTlvVA() const { return in.tlvPointers->getVA(gotIndex); }
  42
  43 Defined::Defined(StringRefZ name, InputFile *file, InputSection *isec,
  44                  uint64_t value, uint64_t size, bool isWeakDef, bool isExternal,
  45                  bool isPrivateExtern, bool includeInSymtab, bool isThumb,
  46                  bool isReferencedDynamically, bool noDeadStrip,
  47                  bool canOverrideWeakDef, bool isWeakDefCanBeHidden,
  48                  bool interposable)
  49     : Symbol(DefinedKind, name, file), overridesWeakDef(canOverrideWeakDef),
  50       privateExtern(isPrivateExtern), includeInSymtab(includeInSymtab),
  51       wasIdenticalCodeFolded(false), thumb(isThumb),
  52       referencedDynamically(isReferencedDynamically), noDeadStrip(noDeadStrip),
  53       interposable(interposable), weakDefCanBeHidden(isWeakDefCanBeHidden),
  54       weakDef(isWeakDef), external(isExternal), isec(isec), value(value),
  55       size(size) {
  56   if (isec) {
  57     isec->symbols.push_back(this);
  58     // Maintain sorted order.
  59     for (auto it = isec->symbols.rbegin(), rend = isec->symbols.rend();
  60          it != rend; ++it) {
  61       auto next = std::next(it);
  62       if (next == rend)
  63         break;
  64       if ((*it)->value < (*next)->value)
  65         std::swap(*next, *it);
  66       else
  67         break;
  68     }
  69   }
  70 }
  71
  72 bool Defined::isTlv() const {
  73   return !isAbsolute() && isThreadLocalVariables(isec->getFlags());
  74 }
  75
  76 uint64_t Defined::getVA() const {
  77   assert(isLive() && "this should only be called for live symbols");
  78
  79   if (isAbsolute())
  80     return value;
  81
  82   if (!isec->isFinal) {
  83     // A target arch that does not use thunks ought never ask for
  84     // the address of a function that has not yet been finalized.
  85     assert(target->usesThunks());
  86
  87     // ConcatOutputSection::finalize() can seek the address of a
  88     // function before its address is assigned. The thunking algorithm
  89     // knows that unfinalized functions will be out of range, so it is
  90     // expedient to return a contrived out-of-range address.
  91     return TargetInfo::outOfRangeVA;
  92   }
  93   return isec->getVA(value);
  94 }
  95
  96 void Defined::canonicalize() {
  97   if (unwindEntry)
  98     unwindEntry = unwindEntry->canonical();
  99   if (isec)
 100     isec = isec->canonical();
 101 }
 102
 103 std::string Defined::getSourceLocation() {
 104   if (!isec)
 105     return {};
 106   return isec->getSourceLocation(value);
 107 }
 108
 109 uint64_t DylibSymbol::getVA() const {
 110   return isInStubs() ? getStubVA() : Symbol::getVA();
 111 }
 112
 113 void LazyArchive::fetchArchiveMember() { getFile()->fetch(sym); }