LLVM 22.0.0git
PPCTargetObjectFile.cpp
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1//===-- PPCTargetObjectFile.cpp - PPC Object Info -------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
12#include "llvm/MC/MCContext.h"
13#include "llvm/MC/MCExpr.h"
14
15using namespace llvm;
16
17void
18PPC64LinuxTargetObjectFile::
19Initialize(MCContext &Ctx, const TargetMachine &TM) {
21}
22
23MCSection *PPC64LinuxTargetObjectFile::SelectSectionForGlobal(
24 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
25 // Here override ReadOnlySection to DataRelROSection for PPC64 SVR4 ABI
26 // when we have a constant that contains global relocations. This is
27 // necessary because of this ABI's handling of pointers to functions in
28 // a shared library. The address of a function is actually the address
29 // of a function descriptor, which resides in the .opd section. Generated
30 // code uses the descriptor directly rather than going via the GOT as some
31 // other ABIs do, which means that initialized function pointers must
32 // reference the descriptor. The linker must convert copy relocs of
33 // pointers to functions in shared libraries into dynamic relocations,
34 // because of an ordering problem with initialization of copy relocs and
35 // PLT entries. The dynamic relocation will be initialized by the dynamic
36 // linker, so we must use DataRelROSection instead of ReadOnlySection.
37 // For more information, see the description of ELIMINATE_COPY_RELOCS in
38 // GNU ld.
39 if (Kind.isReadOnly()) {
40 const auto *GVar = dyn_cast<GlobalVariable>(GO);
41
42 if (GVar && GVar->isConstant() &&
43 GVar->getInitializer()->needsDynamicRelocation())
45 }
46
48}
49
50const MCExpr *PPC64LinuxTargetObjectFile::
51getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
52 const MCExpr *Expr =
54 return MCBinaryExpr::createAdd(Expr,
56 getContext());
57}
58
static const MCBinaryExpr * createAdd(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx, SMLoc Loc=SMLoc())
Definition MCExpr.h:343
static LLVM_ABI const MCConstantExpr * create(int64_t Value, MCContext &Ctx, bool PrintInHex=false, unsigned SizeInBytes=0)
Definition MCExpr.cpp:212
Context object for machine code objects.
Definition MCContext.h:83
Base class for the full range of assembler expressions which are needed for parsing.
Definition MCExpr.h:34
MCContext & getContext() const
Instances of this class represent a uniqued identifier for a section in the current translation unit.
Definition MCSection.h:496
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx, SMLoc Loc=SMLoc())
Definition MCExpr.h:214
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition MCSymbol.h:42
SectionKind - This is a simple POD value that classifies the properties of a section.
Definition SectionKind.h:22
static SectionKind getReadOnlyWithRel()
void Initialize(MCContext &Ctx, const TargetMachine &TM) override
This method must be called before any actual lowering is done.
MCSection * SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const override
Primary interface to the complete machine description for the target machine.
This is an optimization pass for GlobalISel generic memory operations.
decltype(auto) dyn_cast(const From &Val)
dyn_cast<X> - Return the argument parameter cast to the specified type.
Definition Casting.h:649