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 "llvm/Demangle/Demangle.h"
13
14using namespace llvm;
15using namespace lld;
16using namespace lld::macho;
17
18static_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)
24static_assert(sizeof(void *) != 8 || sizeof(Defined) == 88,
25              "Try to minimize Defined's size; we create many instances");
26#endif
27
28static_assert(sizeof(SymbolUnion) == sizeof(Defined),
29              "Defined should be the largest Symbol kind");
30
31// Returns a symbol name for an error message.
32static std::string maybeDemangleSymbol(StringRef symName) {
33  if (config->demangle) {
34    symName.consume_front("_");
35    return demangle(symName);
36  }
37  return symName.str();
38}
39
40std::string lld::toString(const Symbol &sym) {
41  return maybeDemangleSymbol(sym.getName());
42}
43
44std::string lld::toMachOString(const object::Archive::Symbol &b) {
45  return maybeDemangleSymbol(b.getName());
46}
47
48uint64_t Symbol::getStubVA() const { return in.stubs->getVA(stubsIndex); }
49uint64_t Symbol::getLazyPtrVA() const {
50  return in.lazyPointers->getVA(stubsIndex);
51}
52uint64_t Symbol::getGotVA() const { return in.got->getVA(gotIndex); }
53uint64_t Symbol::getTlvVA() const { return in.tlvPointers->getVA(gotIndex); }
54
55Defined::Defined(StringRefZ name, InputFile *file, InputSection *isec,
56                 uint64_t value, uint64_t size, bool isWeakDef, bool isExternal,
57                 bool isPrivateExtern, bool includeInSymtab,
58                 bool isReferencedDynamically, bool noDeadStrip,
59                 bool canOverrideWeakDef, bool isWeakDefCanBeHidden,
60                 bool interposable)
61    : Symbol(DefinedKind, name, file), overridesWeakDef(canOverrideWeakDef),
62      privateExtern(isPrivateExtern), includeInSymtab(includeInSymtab),
63      wasIdenticalCodeFolded(false),
64      referencedDynamically(isReferencedDynamically), noDeadStrip(noDeadStrip),
65      interposable(interposable), weakDefCanBeHidden(isWeakDefCanBeHidden),
66      weakDef(isWeakDef), external(isExternal), isec(isec), value(value),
67      size(size) {
68  if (isec) {
69    isec->symbols.push_back(this);
70    // Maintain sorted order.
71    for (auto it = isec->symbols.rbegin(), rend = isec->symbols.rend();
72         it != rend; ++it) {
73      auto next = std::next(it);
74      if (next == rend)
75        break;
76      if ((*it)->value < (*next)->value)
77        std::swap(*next, *it);
78      else
79        break;
80    }
81  }
82}
83
84bool Defined::isTlv() const {
85  return !isAbsolute() && isThreadLocalVariables(isec->getFlags());
86}
87
88uint64_t Defined::getVA() const {
89  assert(isLive() && "this should only be called for live symbols");
90
91  if (isAbsolute())
92    return value;
93
94  if (!isec->isFinal) {
95    // A target arch that does not use thunks ought never ask for
96    // the address of a function that has not yet been finalized.
97    assert(target->usesThunks());
98
99    // ConcatOutputSection::finalize() can seek the address of a
100    // function before its address is assigned. The thunking algorithm
101    // knows that unfinalized functions will be out of range, so it is
102    // expedient to return a contrived out-of-range address.
103    return TargetInfo::outOfRangeVA;
104  }
105  return isec->getVA(value);
106}
107
108ObjFile *Defined::getObjectFile() const {
109  return isec ? dyn_cast_or_null<ObjFile>(isec->getFile()) : nullptr;
110}
111
112void Defined::canonicalize() {
113  if (unwindEntry)
114    unwindEntry = unwindEntry->canonical();
115  if (isec)
116    isec = isec->canonical();
117}
118
119std::string Defined::getSourceLocation() {
120  if (!isec)
121    return {};
122  return isec->getSourceLocation(value);
123}
124
125uint64_t DylibSymbol::getVA() const {
126  return isInStubs() ? getStubVA() : Symbol::getVA();
127}
128
129void LazyArchive::fetchArchiveMember() { getFile()->fetch(sym); }
130