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
9#include "PPCTargetObjectFile.h"
10#include "llvm/IR/GlobalVariable.h"
11#include "llvm/IR/Mangler.h"
12#include "llvm/MC/MCContext.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCSectionELF.h"
15
16using namespace llvm;
17
18void
19PPC64LinuxTargetObjectFile::
20Initialize(MCContext &Ctx, const TargetMachine &TM) {
21 TargetLoweringObjectFileELF::Initialize(Ctx, TM);
22}
23
24MCSection *PPC64LinuxTargetObjectFile::SelectSectionForGlobal(
25 const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
26 // Here override ReadOnlySection to DataRelROSection for PPC64 SVR4 ABI
27 // when we have a constant that contains global relocations. This is
28 // necessary because of this ABI's handling of pointers to functions in
29 // a shared library. The address of a function is actually the address
30 // of a function descriptor, which resides in the .opd section. Generated
31 // code uses the descriptor directly rather than going via the GOT as some
32 // other ABIs do, which means that initialized function pointers must
33 // reference the descriptor. The linker must convert copy relocs of
34 // pointers to functions in shared libraries into dynamic relocations,
35 // because of an ordering problem with initialization of copy relocs and
36 // PLT entries. The dynamic relocation will be initialized by the dynamic
37 // linker, so we must use DataRelROSection instead of ReadOnlySection.
38 // For more information, see the description of ELIMINATE_COPY_RELOCS in
39 // GNU ld.
40 if (Kind.isReadOnly()) {
41 const auto *GVar = dyn_cast<GlobalVariable>(Val: GO);
42
43 if (GVar && GVar->isConstant() &&
44 GVar->getInitializer()->needsDynamicRelocation())
45 Kind = SectionKind::getReadOnlyWithRel();
46 }
47
48 return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, Kind, TM);
49}
50
51const MCExpr *PPC64LinuxTargetObjectFile::
52getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
53 const MCExpr *Expr =
54 MCSymbolRefExpr::create(Symbol: Sym, Kind: MCSymbolRefExpr::VK_DTPREL, Ctx&: getContext());
55 return MCBinaryExpr::createAdd(LHS: Expr,
56 RHS: MCConstantExpr::create(Value: 0x8000, Ctx&: getContext()),
57 Ctx&: getContext());
58}
59
60