llvm-project/lld/MachO/InputSection.cpp

113 lines
3.8 KiB
C++

//===- InputSection.cpp ---------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "InputSection.h"
#include "InputFiles.h"
#include "OutputSegment.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "Target.h"
#include "Writer.h"
#include "lld/Common/Memory.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
using namespace llvm::MachO;
using namespace llvm::support;
using namespace lld;
using namespace lld::macho;
std::vector<InputSection *> macho::inputSections;
uint64_t InputSection::getFileOffset() const {
return parent->fileOff + outSecFileOff;
}
uint64_t InputSection::getFileSize() const {
return isZeroFill(flags) ? 0 : getSize();
}
uint64_t InputSection::getVA() const { return parent->addr + outSecOff; }
static uint64_t resolveSymbolVA(uint8_t *loc, const Symbol &sym, uint8_t type) {
const RelocAttrs &relocAttrs = target->getRelocAttrs(type);
if (relocAttrs.hasAttr(RelocAttrBits::BRANCH)) {
if (sym.isInStubs())
return in.stubs->addr + sym.stubsIndex * target->stubSize;
} else if (relocAttrs.hasAttr(RelocAttrBits::GOT)) {
if (sym.isInGot())
return in.got->addr + sym.gotIndex * target->wordSize;
} else if (relocAttrs.hasAttr(RelocAttrBits::TLV)) {
if (sym.isInGot())
return in.tlvPointers->addr + sym.gotIndex * target->wordSize;
assert(isa<Defined>(&sym));
}
return sym.getVA();
}
void InputSection::writeTo(uint8_t *buf) {
if (getFileSize() == 0)
return;
memcpy(buf, data.data(), data.size());
for (size_t i = 0; i < relocs.size(); i++) {
const Reloc &r = relocs[i];
uint8_t *loc = buf + r.offset;
uint64_t referentVA = 0;
if (target->hasAttr(r.type, RelocAttrBits::SUBTRAHEND)) {
const Symbol *fromSym = r.referent.get<Symbol *>();
const Reloc &minuend = relocs[++i];
uint64_t minuendVA;
if (const Symbol *toSym = minuend.referent.dyn_cast<Symbol *>())
minuendVA = toSym->getVA();
else
minuendVA = minuend.referent.get<InputSection *>()->getVA();
referentVA = minuendVA - fromSym->getVA() + minuend.addend;
} else if (auto *referentSym = r.referent.dyn_cast<Symbol *>()) {
if (target->hasAttr(r.type, RelocAttrBits::LOAD) &&
!referentSym->isInGot())
target->relaxGotLoad(loc, r.type);
referentVA = resolveSymbolVA(loc, *referentSym, r.type);
if (isThreadLocalVariables(flags)) {
// References from thread-local variable sections are treated as offsets
// relative to the start of the thread-local data memory area, which
// is initialized via copying all the TLV data sections (which are all
// contiguous).
if (isa<Defined>(referentSym))
referentVA -= firstTLVDataSection->addr;
}
} else if (auto *referentIsec = r.referent.dyn_cast<InputSection *>()) {
referentVA = referentIsec->getVA();
}
target->relocateOne(loc, r, referentVA + r.addend, getVA() + r.offset);
}
}
bool macho::isCodeSection(InputSection *isec) {
uint32_t type = isec->flags & SECTION_TYPE;
if (type != S_REGULAR && type != S_COALESCED)
return false;
uint32_t attr = isec->flags & SECTION_ATTRIBUTES_USR;
if (attr == S_ATTR_PURE_INSTRUCTIONS)
return true;
if (isec->segname == segment_names::text)
return StringSwitch<bool>(isec->name)
.Cases(section_names::textCoalNt, section_names::staticInit, true)
.Default(false);
return false;
}
std::string lld::toString(const InputSection *isec) {
return (toString(isec->file) + ":(" + isec->name + ")").str();
}