6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
64 lines
2.1 KiB
C++
64 lines
2.1 KiB
C++
//===- MCELFExtras.h - Extra functions for ELF ------------------*- C++ -*-===//
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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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#ifndef LLVM_MC_MCELFEXTRAS_H
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#define LLVM_MC_MCELFEXTRAS_H
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/bit.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/Support/LEB128.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cstdint>
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#include <type_traits>
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namespace llvm::ELF {
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// Encode relocations as CREL to OS. ToCrel is responsible for converting a
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// const RelocsTy & to an Elf_Crel.
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template <bool Is64, class RelocsTy, class F>
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void encodeCrel(raw_ostream &OS, RelocsTy Relocs, F ToCrel) {
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using uint = std::conditional_t<Is64, uint64_t, uint32_t>;
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uint OffsetMask = 8, Offset = 0, Addend = 0;
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uint32_t SymIdx = 0, Type = 0;
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for (const auto &R : Relocs)
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OffsetMask |= ToCrel(R).r_offset;
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const int Shift = llvm::countr_zero(OffsetMask);
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encodeULEB128(Relocs.size() * 8 + ELF::CREL_HDR_ADDEND + Shift, OS);
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for (const auto &R : Relocs) {
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auto CR = ToCrel(R);
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auto DeltaOffset = static_cast<uint>((CR.r_offset - Offset) >> Shift);
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Offset = CR.r_offset;
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uint8_t B = (DeltaOffset << 3) + (SymIdx != CR.r_symidx) +
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(Type != CR.r_type ? 2 : 0) +
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(Addend != uint(CR.r_addend) ? 4 : 0);
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if (DeltaOffset < 0x10) {
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OS << char(B);
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} else {
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OS << char(B | 0x80);
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encodeULEB128(DeltaOffset >> 4, OS);
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}
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// Delta symidx/type/addend members (SLEB128).
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if (B & 1) {
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encodeSLEB128(static_cast<int32_t>(CR.r_symidx - SymIdx), OS);
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SymIdx = CR.r_symidx;
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}
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if (B & 2) {
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encodeSLEB128(static_cast<int32_t>(CR.r_type - Type), OS);
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Type = CR.r_type;
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}
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if (B & 4) {
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encodeSLEB128(std::make_signed_t<uint>(CR.r_addend - Addend), OS);
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Addend = CR.r_addend;
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}
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}
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}
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} // namespace llvm::ELF
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#endif
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