MipsTargetObjectFile.cpp revision ebe69fe11e48d322045d5949c83283927a0d790b
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" 120b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/DataLayout.h" 130b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/DerivedTypes.h" 140b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/GlobalVariable.h" 15287df1bc0309962770b6c176f2d143795dd3cc2fChris Lattner#include "llvm/MC/MCContext.h" 16b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/MC/MCSectionELF.h" 17b71b909bc76f48377fc96547d53a088346852600Chris Lattner#include "llvm/Support/CommandLine.h" 18c85dca66e68c9fa6ffa8471c64113b12d8d94fb1Rafael Espindola#include "llvm/Support/ELF.h" 19d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/Target/TargetMachine.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 2737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesstatic cl::opt<bool> 2837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesLocalSData("mlocal-sdata", cl::Hidden, 2937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines cl::desc("MIPS: Use gp_rel for object-local data."), 3037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines cl::init(true)); 3137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines 3237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesstatic cl::opt<bool> 3337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesExternSData("mextern-sdata", cl::Hidden, 3437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines cl::desc("MIPS: Use gp_rel for data that is not defined by the " 3537ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines "current object."), 3637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines cl::init(true)); 3737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines 38b71b909bc76f48377fc96547d53a088346852600Chris Lattnervoid MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){ 39b71b909bc76f48377fc96547d53a088346852600Chris Lattner TargetLoweringObjectFileELF::Initialize(Ctx, TM); 40fd91d8dd7e18107b35c7332b92d636420517e3cbLogan Chien InitializeELF(TM.Options.UseInitArray); 4136919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 42ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines SmallDataSection = getContext().getELFSection( 43ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines ".sdata", ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC); 44ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 45ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines SmallBSSSection = getContext().getELFSection(".sbss", ELF::SHT_NOBITS, 46ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines ELF::SHF_WRITE | ELF::SHF_ALLOC); 4737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines this->TM = &TM; 48b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 49b71b909bc76f48377fc96547d53a088346852600Chris Lattner 5036919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou// A address must be loaded from a small section if its size is less than the 5136919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou// small section size threshold. Data in this section must be addressed using 52b71b909bc76f48377fc96547d53a088346852600Chris Lattner// gp_rel operator. 53b71b909bc76f48377fc96547d53a088346852600Chris Lattnerstatic bool IsInSmallSection(uint64_t Size) { 5437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // gcc has traditionally not treated zero-sized objects as small data, so this 5537ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // is effectively part of the ABI. 56b71b909bc76f48377fc96547d53a088346852600Chris Lattner return Size > 0 && Size <= SSThreshold; 57b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 58b71b909bc76f48377fc96547d53a088346852600Chris Lattner 5937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// Return true if this global address should be placed into small data/bss 6037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// section. 6137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesbool MipsTargetObjectFile:: 6237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesIsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM) const { 6337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // We first check the case where global is a declaration, because finding 6437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // section kind using getKindForGlobal() is only allowed for global 6537ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // definitions. 66b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) 6737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines return IsGlobalInSmallSectionImpl(GV, TM); 6836919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 69b71b909bc76f48377fc96547d53a088346852600Chris Lattner return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM)); 70b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 71b71b909bc76f48377fc96547d53a088346852600Chris Lattner 7237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// Return true if this global address should be placed into small data/bss 7337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// section. 74b71b909bc76f48377fc96547d53a088346852600Chris Lattnerbool MipsTargetObjectFile:: 75b71b909bc76f48377fc96547d53a088346852600Chris LattnerIsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM, 76b71b909bc76f48377fc96547d53a088346852600Chris Lattner SectionKind Kind) const { 7737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines return (IsGlobalInSmallSectionImpl(GV, TM) && 7837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines (Kind.isDataRel() || Kind.isBSS() || Kind.isCommon())); 7937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines} 800046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes 8137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// Return true if this global address should be placed into small data/bss 8237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// section. This method does all the work, except for checking the section 8337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// kind. 8437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesbool MipsTargetObjectFile:: 8537ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesIsGlobalInSmallSectionImpl(const GlobalValue *GV, 8637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines const TargetMachine &TM) const { 870046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>(); 88e7338cd550a4ccde6796d2987b482ea9f0e239efAkira Hatanaka 89e7338cd550a4ccde6796d2987b482ea9f0e239efAkira Hatanaka // Return if small section is not available. 90e7338cd550a4ccde6796d2987b482ea9f0e239efAkira Hatanaka if (!Subtarget.useSmallSection()) 910046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes return false; 920046de0550f781b7739ffd5a6fe138cb306a1cf4Bruno Cardoso Lopes 93b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Only global variables, not functions. 94b71b909bc76f48377fc96547d53a088346852600Chris Lattner const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV); 95b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (!GVA) 96b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 9736919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 9837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // Enforce -mlocal-sdata. 9937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (!LocalSData && GV->hasLocalLinkage()) 100b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 10136919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 10237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // Enforce -mextern-sdata. 10337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (!ExternSData && ((GV->hasExternalLinkage() && GV->isDeclaration()) || 10437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines GV->hasCommonLinkage())) 105b71b909bc76f48377fc96547d53a088346852600Chris Lattner return false; 106b71b909bc76f48377fc96547d53a088346852600Chris Lattner 107db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner Type *Ty = GV->getType()->getElementType(); 108ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines return IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(Ty)); 109b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 110b71b909bc76f48377fc96547d53a088346852600Chris Lattner 111b71b909bc76f48377fc96547d53a088346852600Chris Lattnerconst MCSection *MipsTargetObjectFile:: 112b71b909bc76f48377fc96547d53a088346852600Chris LattnerSelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 11336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Mangler &Mang, const TargetMachine &TM) const { 114b71b909bc76f48377fc96547d53a088346852600Chris Lattner // TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*" 115b71b909bc76f48377fc96547d53a088346852600Chris Lattner // sections? 11636919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 117b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Handle Small Section classification here. 118b71b909bc76f48377fc96547d53a088346852600Chris Lattner if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind)) 119b71b909bc76f48377fc96547d53a088346852600Chris Lattner return SmallBSSSection; 12037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (Kind.isDataRel() && IsGlobalInSmallSection(GV, TM, Kind)) 121b71b909bc76f48377fc96547d53a088346852600Chris Lattner return SmallDataSection; 12236919ac8a57a691f07129bb903fe32ae182b68c2Che-Liang Chiou 123b71b909bc76f48377fc96547d53a088346852600Chris Lattner // Otherwise, we work the same as ELF. 1244552c9a3b34ad9b2085635266348d0d9b95514a6Akira Hatanaka return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM); 125b71b909bc76f48377fc96547d53a088346852600Chris Lattner} 12637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines 12737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines/// Return true if this constant should be placed into small data section. 12837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesbool MipsTargetObjectFile:: 12937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesIsConstantInSmallSection(const Constant *CN, const TargetMachine &TM) const { 130ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines return ( 131ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines TM.getSubtarget<MipsSubtarget>().useSmallSection() && LocalSData && 132ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(CN->getType()))); 13337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines} 13437ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines 13537ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hinesconst MCSection *MipsTargetObjectFile:: 13637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesgetSectionForConstant(SectionKind Kind, const Constant *C) const { 13737ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (IsConstantInSmallSection(C, *TM)) 13837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines return SmallDataSection; 13937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines 14037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines // Otherwise, we work the same as ELF. 14137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines return TargetLoweringObjectFileELF::getSectionForConstant(Kind, C); 14237ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines} 143