75 lines
2.4 KiB
C++
75 lines
2.4 KiB
C++
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//===- OutputSection.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 "MergedOutputSection.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Memory.h"
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#include "llvm/BinaryFormat/MachO.h"
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using namespace llvm;
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using namespace llvm::MachO;
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using namespace lld;
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using namespace lld::macho;
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void MergedOutputSection::mergeInput(InputSection *input) {
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if (inputs.empty()) {
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align = input->align;
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flags = input->flags;
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} else {
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mergeFlags(input->flags);
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align = std::max(align, input->align);
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}
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inputs.push_back(input);
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input->parent = this;
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}
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void MergedOutputSection::finalize() {
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uint64_t isecAddr = addr;
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uint64_t isecFileOff = fileOff;
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for (InputSection *isec : inputs) {
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isecAddr = alignTo(isecAddr, isec->align);
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isecFileOff = alignTo(isecFileOff, isec->align);
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isec->outSecOff = isecAddr - addr;
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isec->outSecFileOff = isecFileOff - fileOff;
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isecAddr += isec->getSize();
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isecFileOff += isec->getFileSize();
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}
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size = isecAddr - addr;
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fileSize = isecFileOff - fileOff;
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}
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void MergedOutputSection::writeTo(uint8_t *buf) const {
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for (InputSection *isec : inputs) {
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isec->writeTo(buf + isec->outSecFileOff);
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}
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}
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// TODO: this is most likely wrong; reconsider how section flags
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// are actually merged. The logic presented here was written without
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// any form of informed research.
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void MergedOutputSection::mergeFlags(uint32_t inputFlags) {
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uint8_t sectionFlag = MachO::SECTION_TYPE & inputFlags;
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if (sectionFlag != (MachO::SECTION_TYPE & flags))
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error("Cannot add merge section; inconsistent type flags " +
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Twine(sectionFlag));
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uint32_t inconsistentFlags =
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MachO::S_ATTR_DEBUG | MachO::S_ATTR_STRIP_STATIC_SYMS |
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MachO::S_ATTR_NO_DEAD_STRIP | MachO::S_ATTR_LIVE_SUPPORT;
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if ((inputFlags ^ flags) & inconsistentFlags)
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error("Cannot add merge section; cannot merge inconsistent flags");
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// Negate pure instruction presence if any section isn't pure.
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uint32_t pureMask = ~MachO::S_ATTR_PURE_INSTRUCTIONS | (inputFlags & flags);
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// Merge the rest
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flags |= inputFlags;
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flags &= pureMask;
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}
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