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 // Returns a symbol for an error message. 18 static std::string demangle(StringRef symName) { 19 if (config->demangle) 20 return demangleItanium(symName); 21 return std::string(symName); 22 } 23 24 std::string lld::toString(const Symbol &sym) { return demangle(sym.getName()); } 25 26 std::string lld::toMachOString(const object::Archive::Symbol &b) { 27 return demangle(b.getName()); 28 } 29 30 uint64_t Symbol::getStubVA() const { return in.stubs->getVA(stubsIndex); } 31 uint64_t Symbol::getGotVA() const { return in.got->getVA(gotIndex); } 32 uint64_t Symbol::getTlvVA() const { return in.tlvPointers->getVA(gotIndex); } 33 34 bool Symbol::isLive() const { 35 if (isa<DylibSymbol>(this) || isa<Undefined>(this)) 36 return used; 37 38 if (auto *d = dyn_cast<Defined>(this)) { 39 // Non-absolute symbols might be alive because their section is 40 // no_dead_strip or live_support. In that case, the section will know 41 // that it's live but `used` might be false. Non-absolute symbols always 42 // have to use the section's `live` bit as source of truth. 43 if (d->isAbsolute()) 44 return used; 45 return d->isec->canonical()->isLive(d->value); 46 } 47 48 assert(!isa<CommonSymbol>(this) && 49 "replaceCommonSymbols() runs before dead code stripping, and isLive() " 50 "should only be called after dead code stripping"); 51 52 // Assume any other kind of symbol is live. 53 return true; 54 } 55 56 uint64_t Defined::getVA() const { 57 assert(isLive() && "this should only be called for live symbols"); 58 59 if (isAbsolute()) 60 return value; 61 62 if (!isec->canonical()->isFinal) { 63 // A target arch that does not use thunks ought never ask for 64 // the address of a function that has not yet been finalized. 65 assert(target->usesThunks()); 66 67 // ConcatOutputSection::finalize() can seek the address of a 68 // function before its address is assigned. The thunking algorithm 69 // knows that unfinalized functions will be out of range, so it is 70 // expedient to return a contrived out-of-range address. 71 return TargetInfo::outOfRangeVA; 72 } 73 return isec->canonical()->getVA(value); 74 } 75 76 uint64_t DylibSymbol::getVA() const { 77 return isInStubs() ? getStubVA() : Symbol::getVA(); 78 } 79 80 void LazySymbol::fetchArchiveMember() { getFile()->fetch(sym); } 81