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//===-- PPCTargetObjectFile.cpp - PPC Object Info -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "PPCTargetObjectFile.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/Target/Mangler.h"
using namespace llvm;
void
PPC64LinuxTargetObjectFile::
Initialize(MCContext &Ctx, const TargetMachine &TM) {
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(TM.Options.UseInitArray);
}
const MCSection * PPC64LinuxTargetObjectFile::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
const MCSection *DefaultSection =
TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang, TM);
if (DefaultSection != ReadOnlySection)
return DefaultSection;
// Here override ReadOnlySection to DataRelROSection for PPC64 SVR4 ABI
// when we have a constant that contains global relocations. This is
// necessary because of this ABI's handling of pointers to functions in
// a shared library. The address of a function is actually the address
// of a function descriptor, which resides in the .opd section. Generated
// code uses the descriptor directly rather than going via the GOT as some
// other ABIs do, which means that initialized function pointers must
// reference the descriptor. The linker must convert copy relocs of
// pointers to functions in shared libraries into dynamic relocations,
// because of an ordering problem with initialization of copy relocs and
// PLT entries. The dynamic relocation will be initialized by the dynamic
// linker, so we must use DataRelROSection instead of ReadOnlySection.
// For more information, see the description of ELIMINATE_COPY_RELOCS in
// GNU ld.
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
if (GVar && GVar->isConstant() &&
(GVar->getInitializer()->getRelocationInfo() ==
Constant::GlobalRelocations))
return DataRelROSection;
return DefaultSection;
}
const MCExpr *PPC64LinuxTargetObjectFile::
getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
const MCExpr *Expr =
MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_PPC_DTPREL, getContext());
return MCBinaryExpr::CreateAdd(Expr,
MCConstantExpr::Create(0x8000, getContext()),
getContext());
}
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