1c5707112e7635d1dd2f2cc9c4f42e79a51302ccaJia Liu//===-- MipsTargetObjectFile.cpp - Mips Object Files ----------------------===// 2b71b909bc76f48377fc96547d53a088346852600Chris Lattner// 3b71b909bc76f48377fc96547d53a088346852600Chris Lattner// The LLVM Compiler Infrastructure 4b71b909bc76f48377fc96547d53a088346852600Chris Lattner// 5b71b909bc76f48377fc96547d53a088346852600Chris Lattner// This file is distributed under the University of Illinois Open Source 6b71b909bc76f48377fc96547d53a088346852600Chris Lattner// License. See LICENSE.TXT for details. 7b71b909bc76f48377fc96547d53a088346852600Chris Lattner// 84552c9a3b34ad9b2085635266348d0d9b95514a6Akira Hatanaka//===----------------------------------------------------------------------===// 9b71b909bc76f48377fc96547d53a088346852600Chris Lattner 10b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "MipsTargetObjectFile.h" 110046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes#include "MipsSubtarget.h" 12b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/DerivedTypes.h" 13b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/GlobalVariable.h" 14287df1bc0309962770b6c176f2d143795dd3cc2fChris Lattner#include "llvm/MC/MCContext.h" 15b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/MC/MCSectionELF.h" 16b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/Target/TargetData.h" 17b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/Target/TargetMachine.h" 18b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/Support/CommandLine.h" 19c85dca66e68c9fa6ffa8471c64113b12d8d94fb1Rafael Espindola#include "llvm/Support/ELF.h" 20b71b909bc76f48377fc96547d53a088346852600Chris Lattnerusing namespace llvm; 21b71b909bc76f48377fc96547d53a088346852600Chris Lattner 22b71b909bc76f48377fc96547d53a088346852600Chris Lattnerstatic cl::opt<unsigned> 23b71b909bc76f48377fc96547d53a088346852600Chris LattnerSSThreshold("mips-ssection-threshold", cl::Hidden, 24b71b909bc76f48377fc96547d53a088346852600Chris Lattner cl::desc("Small data and bss section threshold size (default=8)"), 25b71b909bc76f48377fc96547d53a088346852600Chris Lattner cl::init(8)); 26b71b909bc76f48377fc96547d53a088346852600Chris Lattner 27b71b909bc76f48377fc96547d53a088346852600Chris Lattnervoid MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){ 28b71b909bc76f48377fc96547d53a088346852600Chris Lattner TargetLoweringObjectFileELF::Initialize(Ctx, TM); 2936919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 30b71b909bc76f48377fc96547d53a088346852600Chris Lattner SmallDataSection = 31c85dca66e68c9fa6ffa8471c64113b12d8d94fb1Rafael Espindola getContext().getELFSection(".sdata", ELF::SHT_PROGBITS, 321c13026e8f94bd332c0979baa9c777da99d48736Rafael Espindola ELF::SHF_WRITE |ELF::SHF_ALLOC, 33287df1bc0309962770b6c176f2d143795dd3cc2fChris Lattner SectionKind::getDataRel()); 3436919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 35b71b909bc76f48377fc96547d53a088346852600Chris Lattner SmallBSSSection = 36c85dca66e68c9fa6ffa8471c64113b12d8d94fb1Rafael Espindola getContext().getELFSection(".sbss", ELF::SHT_NOBITS, 371c13026e8f94bd332c0979baa9c777da99d48736Rafael Espindola ELF::SHF_WRITE |ELF::SHF_ALLOC, 38287df1bc0309962770b6c176f2d143795dd3cc2fChris Lattner SectionKind::getBSS()); 3936919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 40b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 41b71b909bc76f48377fc96547d53a088346852600Chris Lattner 4236919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou// A address must be loaded from a small section if its size is less than the 4336919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou// small section size threshold. Data in this section must be addressed using 44b71b909bc76f48377fc96547d53a088346852600Chris Lattner// gp_rel operator. 45b71b909bc76f48377fc96547d53a088346852600Chris Lattnerstatic bool IsInSmallSection(uint64_t Size) { 46b71b909bc76f48377fc96547d53a088346852600Chris Lattner return Size > 0 && Size <= SSThreshold; 47b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 48b71b909bc76f48377fc96547d53a088346852600Chris Lattner 49b71b909bc76f48377fc96547d53a088346852600Chris Lattnerbool MipsTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV, 504552c9a3b34ad9b2085635266348d0d9b95514a6Akira Hatanaka const TargetMachine &TM) const { 51b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) 52b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 5336919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 54b71b909bc76f48377fc96547d53a088346852600Chris Lattner return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM)); 55b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 56b71b909bc76f48377fc96547d53a088346852600Chris Lattner 57b71b909bc76f48377fc96547d53a088346852600Chris Lattner/// IsGlobalInSmallSection - Return true if this global address should be 58b71b909bc76f48377fc96547d53a088346852600Chris Lattner/// placed into small data/bss section. 59b71b909bc76f48377fc96547d53a088346852600Chris Lattnerbool MipsTargetObjectFile:: 60b71b909bc76f48377fc96547d53a088346852600Chris LattnerIsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM, 61b71b909bc76f48377fc96547d53a088346852600Chris Lattner SectionKind Kind) const { 620046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes 630046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes // Only use small section for non linux targets. 640046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>(); 650046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes if (Subtarget.isLinux()) 660046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes return false; 670046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes 68b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Only global variables, not functions. 69b71b909bc76f48377fc96547d53a088346852600Chris Lattner const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV); 70b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (!GVA) 71b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 7236919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 73b71b909bc76f48377fc96547d53a088346852600Chris Lattner // We can only do this for datarel or BSS objects for now. 74b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (!Kind.isBSS() && !Kind.isDataRel()) 75b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 7636919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 77b71b909bc76f48377fc96547d53a088346852600Chris Lattner // If this is a internal constant string, there is a special 78b71b909bc76f48377fc96547d53a088346852600Chris Lattner // section for it, but not in small data/bss. 79b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (Kind.isMergeable1ByteCString()) 80b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 81b71b909bc76f48377fc96547d53a088346852600Chris Lattner 82db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner Type *Ty = GV->getType()->getElementType(); 83b71b909bc76f48377fc96547d53a088346852600Chris Lattner return IsInSmallSection(TM.getTargetData()->getTypeAllocSize(Ty)); 84b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 85b71b909bc76f48377fc96547d53a088346852600Chris Lattner 86b71b909bc76f48377fc96547d53a088346852600Chris Lattner 87b71b909bc76f48377fc96547d53a088346852600Chris Lattner 88b71b909bc76f48377fc96547d53a088346852600Chris Lattnerconst MCSection *MipsTargetObjectFile:: 89b71b909bc76f48377fc96547d53a088346852600Chris LattnerSelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 90b71b909bc76f48377fc96547d53a088346852600Chris Lattner Mangler *Mang, const TargetMachine &TM) const { 91b71b909bc76f48377fc96547d53a088346852600Chris Lattner // TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*" 92b71b909bc76f48377fc96547d53a088346852600Chris Lattner // sections? 9336919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 94b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Handle Small Section classification here. 95b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind)) 96b71b909bc76f48377fc96547d53a088346852600Chris Lattner return SmallBSSSection; 97b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind)) 98b71b909bc76f48377fc96547d53a088346852600Chris Lattner return SmallDataSection; 9936919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 100b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Otherwise, we work the same as ELF. 1014552c9a3b34ad9b2085635266348d0d9b95514a6Akira Hatanaka return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM); 102b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 103