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