forked from OSchip/llvm-project
219 lines
6.4 KiB
C++
219 lines
6.4 KiB
C++
//===- Relocations.h -------------------------------------------*- 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 LLD_ELF_RELOCATIONS_H
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#define LLD_ELF_RELOCATIONS_H
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#include "lld/Common/LLVM.h"
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#include "llvm/ADT/DenseMap.h"
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#include <map>
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#include <vector>
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namespace lld {
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namespace elf {
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class Symbol;
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class InputSection;
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class InputSectionBase;
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class OutputSection;
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class SectionBase;
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// Represents a relocation type, such as R_X86_64_PC32 or R_ARM_THM_CALL.
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using RelType = uint32_t;
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using JumpModType = uint32_t;
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// List of target-independent relocation types. Relocations read
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// from files are converted to these types so that the main code
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// doesn't have to know about architecture-specific details.
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enum RelExpr {
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R_ABS,
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R_ADDEND,
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R_DTPREL,
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R_GOT,
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R_GOT_OFF,
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R_GOT_PC,
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R_GOTONLY_PC,
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R_GOTPLTONLY_PC,
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R_GOTPLT,
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R_GOTPLTREL,
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R_GOTREL,
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R_NONE,
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R_PC,
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R_PLT,
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R_PLT_PC,
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R_PLT_GOTPLT,
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R_RELAX_GOT_PC,
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R_RELAX_GOT_PC_NOPIC,
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R_RELAX_TLS_GD_TO_IE,
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R_RELAX_TLS_GD_TO_IE_ABS,
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R_RELAX_TLS_GD_TO_IE_GOT_OFF,
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R_RELAX_TLS_GD_TO_IE_GOTPLT,
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R_RELAX_TLS_GD_TO_LE,
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R_RELAX_TLS_GD_TO_LE_NEG,
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R_RELAX_TLS_IE_TO_LE,
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R_RELAX_TLS_LD_TO_LE,
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R_RELAX_TLS_LD_TO_LE_ABS,
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R_SIZE,
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R_TPREL,
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R_TPREL_NEG,
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R_TLSDESC,
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R_TLSDESC_CALL,
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R_TLSDESC_PC,
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R_TLSDESC_GOTPLT,
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R_TLSGD_GOT,
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R_TLSGD_GOTPLT,
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R_TLSGD_PC,
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R_TLSIE_HINT,
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R_TLSLD_GOT,
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R_TLSLD_GOTPLT,
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R_TLSLD_GOT_OFF,
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R_TLSLD_HINT,
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R_TLSLD_PC,
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// The following is abstract relocation types used for only one target.
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//
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// Even though RelExpr is intended to be a target-neutral representation
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// of a relocation type, there are some relocations whose semantics are
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// unique to a target. Such relocation are marked with R_<TARGET_NAME>.
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R_AARCH64_GOT_PAGE_PC,
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R_AARCH64_GOT_PAGE,
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R_AARCH64_PAGE_PC,
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R_AARCH64_RELAX_TLS_GD_TO_IE_PAGE_PC,
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R_AARCH64_TLSDESC_PAGE,
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R_ARM_PCA,
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R_ARM_SBREL,
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R_MIPS_GOTREL,
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R_MIPS_GOT_GP,
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R_MIPS_GOT_GP_PC,
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R_MIPS_GOT_LOCAL_PAGE,
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R_MIPS_GOT_OFF,
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R_MIPS_GOT_OFF32,
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R_MIPS_TLSGD,
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R_MIPS_TLSLD,
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R_PPC32_PLTREL,
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R_PPC64_CALL,
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R_PPC64_CALL_PLT,
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R_PPC64_RELAX_TOC,
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R_PPC64_TOCBASE,
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R_PPC64_RELAX_GOT_PC,
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R_RISCV_ADD,
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R_RISCV_PC_INDIRECT,
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};
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// Architecture-neutral representation of relocation.
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struct Relocation {
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RelExpr expr;
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RelType type;
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uint64_t offset;
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int64_t addend;
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Symbol *sym;
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};
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// Manipulate jump instructions with these modifiers. These are used to relax
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// jump instruction opcodes at basic block boundaries and are particularly
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// useful when basic block sections are enabled.
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struct JumpInstrMod {
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JumpModType original;
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uint64_t offset;
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unsigned size;
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};
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// This function writes undefined symbol diagnostics to an internal buffer.
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// Call reportUndefinedSymbols() after calling scanRelocations() to emit
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// the diagnostics.
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template <class ELFT> void scanRelocations(InputSectionBase &);
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void postScanRelocations();
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template <class ELFT> void reportUndefinedSymbols();
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void hexagonTLSSymbolUpdate(ArrayRef<OutputSection *> outputSections);
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bool hexagonNeedsTLSSymbol(ArrayRef<OutputSection *> outputSections);
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class ThunkSection;
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class Thunk;
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class InputSectionDescription;
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class ThunkCreator {
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public:
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// Return true if Thunks have been added to OutputSections
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bool createThunks(ArrayRef<OutputSection *> outputSections);
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// The number of completed passes of createThunks this permits us
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// to do one time initialization on Pass 0 and put a limit on the
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// number of times it can be called to prevent infinite loops.
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uint32_t pass = 0;
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private:
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void mergeThunks(ArrayRef<OutputSection *> outputSections);
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ThunkSection *getISDThunkSec(OutputSection *os, InputSection *isec,
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InputSectionDescription *isd,
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const Relocation &rel, uint64_t src);
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ThunkSection *getISThunkSec(InputSection *isec);
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void createInitialThunkSections(ArrayRef<OutputSection *> outputSections);
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std::pair<Thunk *, bool> getThunk(InputSection *isec, Relocation &rel,
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uint64_t src);
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ThunkSection *addThunkSection(OutputSection *os, InputSectionDescription *,
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uint64_t off);
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bool normalizeExistingThunk(Relocation &rel, uint64_t src);
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// Record all the available Thunks for a (Symbol, addend) pair, where Symbol
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// is represented as a (section, offset) pair. There may be multiple
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// relocations sharing the same (section, offset + addend) pair. We may revert
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// a relocation back to its original non-Thunk target, and restore the
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// original addend, so we cannot fold offset + addend. A nested pair is used
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// because DenseMapInfo is not specialized for std::tuple.
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llvm::DenseMap<std::pair<std::pair<SectionBase *, uint64_t>, int64_t>,
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std::vector<Thunk *>>
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thunkedSymbolsBySectionAndAddend;
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llvm::DenseMap<std::pair<Symbol *, int64_t>, std::vector<Thunk *>>
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thunkedSymbols;
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// Find a Thunk from the Thunks symbol definition, we can use this to find
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// the Thunk from a relocation to the Thunks symbol definition.
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llvm::DenseMap<Symbol *, Thunk *> thunks;
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// Track InputSections that have an inline ThunkSection placed in front
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// an inline ThunkSection may have control fall through to the section below
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// so we need to make sure that there is only one of them.
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// The Mips LA25 Thunk is an example of an inline ThunkSection.
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llvm::DenseMap<InputSection *, ThunkSection *> thunkedSections;
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};
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// Return a int64_t to make sure we get the sign extension out of the way as
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// early as possible.
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template <class ELFT>
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static inline int64_t getAddend(const typename ELFT::Rel &rel) {
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return 0;
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}
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template <class ELFT>
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static inline int64_t getAddend(const typename ELFT::Rela &rel) {
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return rel.r_addend;
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}
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template <typename RelTy>
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ArrayRef<RelTy> sortRels(ArrayRef<RelTy> rels, SmallVector<RelTy, 0> &storage) {
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auto cmp = [](const RelTy &a, const RelTy &b) {
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return a.r_offset < b.r_offset;
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};
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if (!llvm::is_sorted(rels, cmp)) {
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storage.assign(rels.begin(), rels.end());
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llvm::stable_sort(storage, cmp);
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rels = storage;
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}
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return rels;
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}
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} // namespace elf
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} // namespace lld
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#endif
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