1259698Sdim//===-- PPCTargetObjectFile.cpp - PPC Object Info -------------------------===// 2259698Sdim// 3259698Sdim// The LLVM Compiler Infrastructure 4259698Sdim// 5259698Sdim// This file is distributed under the University of Illinois Open Source 6259698Sdim// License. See LICENSE.TXT for details. 7259698Sdim// 8259698Sdim//===----------------------------------------------------------------------===// 9259698Sdim 10259698Sdim#include "PPCTargetObjectFile.h" 11259698Sdim#include "llvm/MC/MCContext.h" 12259698Sdim#include "llvm/MC/MCExpr.h" 13259698Sdim#include "llvm/MC/MCSectionELF.h" 14259698Sdim#include "llvm/Target/Mangler.h" 15259698Sdim 16259698Sdimusing namespace llvm; 17259698Sdim 18259698Sdimvoid 19259698SdimPPC64LinuxTargetObjectFile:: 20259698SdimInitialize(MCContext &Ctx, const TargetMachine &TM) { 21259698Sdim TargetLoweringObjectFileELF::Initialize(Ctx, TM); 22259698Sdim InitializeELF(TM.Options.UseInitArray); 23259698Sdim} 24259698Sdim 25259698Sdimconst MCSection * PPC64LinuxTargetObjectFile:: 26259698SdimSelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 27259698Sdim Mangler *Mang, const TargetMachine &TM) const { 28259698Sdim 29259698Sdim const MCSection *DefaultSection = 30259698Sdim TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang, TM); 31259698Sdim 32259698Sdim if (DefaultSection != ReadOnlySection) 33259698Sdim return DefaultSection; 34259698Sdim 35259698Sdim // Here override ReadOnlySection to DataRelROSection for PPC64 SVR4 ABI 36259698Sdim // when we have a constant that contains global relocations. This is 37259698Sdim // necessary because of this ABI's handling of pointers to functions in 38259698Sdim // a shared library. The address of a function is actually the address 39259698Sdim // of a function descriptor, which resides in the .opd section. Generated 40259698Sdim // code uses the descriptor directly rather than going via the GOT as some 41259698Sdim // other ABIs do, which means that initialized function pointers must 42259698Sdim // reference the descriptor. The linker must convert copy relocs of 43259698Sdim // pointers to functions in shared libraries into dynamic relocations, 44259698Sdim // because of an ordering problem with initialization of copy relocs and 45259698Sdim // PLT entries. The dynamic relocation will be initialized by the dynamic 46259698Sdim // linker, so we must use DataRelROSection instead of ReadOnlySection. 47259698Sdim // For more information, see the description of ELIMINATE_COPY_RELOCS in 48259698Sdim // GNU ld. 49259698Sdim const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV); 50259698Sdim 51259698Sdim if (GVar && GVar->isConstant() && 52259698Sdim (GVar->getInitializer()->getRelocationInfo() == 53259698Sdim Constant::GlobalRelocations)) 54259698Sdim return DataRelROSection; 55259698Sdim 56259698Sdim return DefaultSection; 57259698Sdim} 58259698Sdim 59259698Sdimconst MCExpr *PPC64LinuxTargetObjectFile:: 60259698SdimgetDebugThreadLocalSymbol(const MCSymbol *Sym) const { 61259698Sdim const MCExpr *Expr = 62259698Sdim MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_PPC_DTPREL, getContext()); 63259698Sdim return MCBinaryExpr::CreateAdd(Expr, 64259698Sdim MCConstantExpr::Create(0x8000, getContext()), 65259698Sdim getContext()); 66259698Sdim} 67259698Sdim 68