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https://github.com/capstone-engine/llvm-capstone.git
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74871cdad7
Summary: llvm-mc emits `__bss` sections with an offset of zero, but we weren't expecting that in our input, so we were copying non-zero data from the start of the file and putting it in `__bss`, with obviously undesirable runtime results. (It appears that the kernel will copy those nonzero bytes as long as the offset is nonzero, regardless of whether S_ZERO_FILL is set.) I debated on whether to make a special ZeroFillSection -- separate from a regular InputSection -- but it seemed like too much work for now. But I'm happy to refactor if anyone feels strongly about having it as a separate class. Depends on D80857. Reviewers: ruiu, pcc, MaskRay, smeenai, alexshap, gkm, Ktwu, christylee Reviewed By: smeenai Subscribers: llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D80859
49 lines
1.3 KiB
C++
49 lines
1.3 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 "OutputSegment.h"
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#include "Symbols.h"
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#include "Target.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::getVA() const { return parent->addr + outSecOff; }
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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 (Reloc &r : relocs) {
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uint64_t va = 0;
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if (auto *s = r.target.dyn_cast<Symbol *>())
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va = target->getSymbolVA(*s, r.type);
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else if (auto *isec = r.target.dyn_cast<InputSection *>())
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va = isec->getVA();
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uint64_t val = va + r.addend;
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if (r.pcrel)
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val -= getVA() + r.offset;
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target->relocateOne(buf + r.offset, r, val);
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}
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}
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