1aa29dffce
The minuend (but not the subtrahend) can reference a section. Note that we do not yet properly validate that the subtrahend isn't referencing a section; I've filed PR50034 to track that. I've also extended the reloc-subtractor.s test to reorder symbols, to make sure that the addends are being associated with the minuend (and not the subtrahend) relocation. Fixes PR49999. Reviewed By: #lld-macho, thakis Differential Revision: https://reviews.llvm.org/D100804
113 lines
3.8 KiB
C++
113 lines
3.8 KiB
C++
//===- InputSection.cpp ---------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "InputSection.h"
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#include "InputFiles.h"
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#include "OutputSegment.h"
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#include "Symbols.h"
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#include "SyntheticSections.h"
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#include "Target.h"
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#include "Writer.h"
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#include "lld/Common/Memory.h"
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#include "llvm/Support/Endian.h"
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using namespace llvm;
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using namespace llvm::MachO;
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using namespace llvm::support;
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using namespace lld;
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using namespace lld::macho;
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std::vector<InputSection *> macho::inputSections;
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uint64_t InputSection::getFileOffset() const {
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return parent->fileOff + outSecFileOff;
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}
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uint64_t InputSection::getFileSize() const {
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return isZeroFill(flags) ? 0 : getSize();
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}
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uint64_t InputSection::getVA() const { return parent->addr + outSecOff; }
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static uint64_t resolveSymbolVA(uint8_t *loc, const Symbol &sym, uint8_t type) {
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const RelocAttrs &relocAttrs = target->getRelocAttrs(type);
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if (relocAttrs.hasAttr(RelocAttrBits::BRANCH)) {
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if (sym.isInStubs())
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return in.stubs->addr + sym.stubsIndex * target->stubSize;
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} else if (relocAttrs.hasAttr(RelocAttrBits::GOT)) {
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if (sym.isInGot())
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return in.got->addr + sym.gotIndex * target->wordSize;
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} else if (relocAttrs.hasAttr(RelocAttrBits::TLV)) {
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if (sym.isInGot())
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return in.tlvPointers->addr + sym.gotIndex * target->wordSize;
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assert(isa<Defined>(&sym));
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}
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return sym.getVA();
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}
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void InputSection::writeTo(uint8_t *buf) {
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if (getFileSize() == 0)
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return;
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memcpy(buf, data.data(), data.size());
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for (size_t i = 0; i < relocs.size(); i++) {
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const Reloc &r = relocs[i];
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uint8_t *loc = buf + r.offset;
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uint64_t referentVA = 0;
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if (target->hasAttr(r.type, RelocAttrBits::SUBTRAHEND)) {
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const Symbol *fromSym = r.referent.get<Symbol *>();
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const Reloc &minuend = relocs[++i];
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uint64_t minuendVA;
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if (const Symbol *toSym = minuend.referent.dyn_cast<Symbol *>())
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minuendVA = toSym->getVA();
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else
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minuendVA = minuend.referent.get<InputSection *>()->getVA();
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referentVA = minuendVA - fromSym->getVA() + minuend.addend;
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} else if (auto *referentSym = r.referent.dyn_cast<Symbol *>()) {
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if (target->hasAttr(r.type, RelocAttrBits::LOAD) &&
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!referentSym->isInGot())
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target->relaxGotLoad(loc, r.type);
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referentVA = resolveSymbolVA(loc, *referentSym, r.type);
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if (isThreadLocalVariables(flags)) {
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// References from thread-local variable sections are treated as offsets
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// relative to the start of the thread-local data memory area, which
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// is initialized via copying all the TLV data sections (which are all
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// contiguous).
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if (isa<Defined>(referentSym))
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referentVA -= firstTLVDataSection->addr;
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}
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} else if (auto *referentIsec = r.referent.dyn_cast<InputSection *>()) {
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referentVA = referentIsec->getVA();
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}
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target->relocateOne(loc, r, referentVA + r.addend, getVA() + r.offset);
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}
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}
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bool macho::isCodeSection(InputSection *isec) {
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uint32_t type = isec->flags & SECTION_TYPE;
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if (type != S_REGULAR && type != S_COALESCED)
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return false;
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uint32_t attr = isec->flags & SECTION_ATTRIBUTES_USR;
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if (attr == S_ATTR_PURE_INSTRUCTIONS)
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return true;
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if (isec->segname == segment_names::text)
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return StringSwitch<bool>(isec->name)
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.Cases("__textcoal_nt", "__StaticInit", true)
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.Default(false);
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return false;
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}
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std::string lld::toString(const InputSection *isec) {
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return (toString(isec->file) + ":(" + isec->name + ")").str();
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}
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