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