xref: /llvm-project-15.0.7/lld/MachO/Symbols.cpp (revision cf838ebf)
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 Defined::Defined(StringRefZ name, InputFile *file, InputSection *isec,
35                  uint64_t value, uint64_t size, bool isWeakDef, bool isExternal,
36                  bool isPrivateExtern, bool isThumb,
37                  bool isReferencedDynamically, bool noDeadStrip)
38     : Symbol(DefinedKind, name, file), isec(isec), value(value), size(size),
39       overridesWeakDef(false), privateExtern(isPrivateExtern),
40       includeInSymtab(true), thumb(isThumb),
41       referencedDynamically(isReferencedDynamically), noDeadStrip(noDeadStrip),
42       weakDef(isWeakDef), external(isExternal) {
43   if (isec) {
44     isec->symbols.push_back(this);
45     // Maintain sorted order.
46     for (auto it = isec->symbols.rbegin(), rend = isec->symbols.rend();
47          it != rend; ++it) {
48       auto next = std::next(it);
49       if (next == rend)
50         break;
51       if ((*it)->value < (*next)->value)
52         std::swap(*next, *it);
53       else
54         break;
55     }
56   }
57 }
58 
59 bool Defined::isTlv() const {
60   return !isAbsolute() && isThreadLocalVariables(isec->getFlags());
61 }
62 
63 uint64_t Defined::getVA() const {
64   assert(isLive() && "this should only be called for live symbols");
65 
66   if (isAbsolute())
67     return value;
68 
69   if (!isec->isFinal) {
70     // A target arch that does not use thunks ought never ask for
71     // the address of a function that has not yet been finalized.
72     assert(target->usesThunks());
73 
74     // ConcatOutputSection::finalize() can seek the address of a
75     // function before its address is assigned. The thunking algorithm
76     // knows that unfinalized functions will be out of range, so it is
77     // expedient to return a contrived out-of-range address.
78     return TargetInfo::outOfRangeVA;
79   }
80   return isec->getVA(value);
81 }
82 
83 void Defined::canonicalize() {
84   if (compactUnwind)
85     compactUnwind = compactUnwind->canonical();
86   if (isec)
87     isec = isec->canonical();
88 }
89 
90 uint64_t DylibSymbol::getVA() const {
91   return isInStubs() ? getStubVA() : Symbol::getVA();
92 }
93 
94 void LazySymbol::fetchArchiveMember() { getFile()->fetch(sym); }
95