1 //===-- HexagonTargetObjectFile.cpp - Hexagon asm properties --------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains the declarations of the HexagonTargetAsmInfo properties. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "HexagonTargetObjectFile.h" 15 #include "HexagonSubtarget.h" 16 #include "HexagonTargetMachine.h" 17 #include "llvm/IR/DataLayout.h" 18 #include "llvm/IR/DerivedTypes.h" 19 #include "llvm/IR/Function.h" 20 #include "llvm/IR/GlobalVariable.h" 21 #include "llvm/MC/MCContext.h" 22 #include "llvm/Support/CommandLine.h" 23 #include "llvm/Support/ELF.h" 24 25 using namespace llvm; 26 27 static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold", 28 cl::init(8), cl::Hidden); 29 30 void HexagonTargetObjectFile::Initialize(MCContext &Ctx, 31 const TargetMachine &TM) { 32 TargetLoweringObjectFileELF::Initialize(Ctx, TM); 33 34 35 SmallDataSection = 36 getContext().getELFSection(".sdata", ELF::SHT_PROGBITS, 37 ELF::SHF_WRITE | ELF::SHF_ALLOC, 38 SectionKind::getDataRel()); 39 SmallBSSSection = 40 getContext().getELFSection(".sbss", ELF::SHT_NOBITS, 41 ELF::SHF_WRITE | ELF::SHF_ALLOC, 42 SectionKind::getBSS()); 43 } 44 45 // sdata/sbss support taken largely from the MIPS Backend. 46 static bool IsInSmallSection(uint64_t Size) { 47 return Size > 0 && Size <= (uint64_t)SmallDataThreshold; 48 } 49 /// IsGlobalInSmallSection - Return true if this global value should be 50 /// placed into small data/bss section. 51 bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV, 52 const TargetMachine &TM) const { 53 // If the primary definition of this global value is outside the current 54 // translation unit or the global value is available for inspection but not 55 // emission, then do nothing. 56 if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) 57 return false; 58 59 // Otherwise, Check if GV should be in sdata/sbss, when normally it would end 60 // up in getKindForGlobal(GV, TM). 61 return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM)); 62 } 63 64 /// IsGlobalInSmallSection - Return true if this global value should be 65 /// placed into small data/bss section. 66 bool HexagonTargetObjectFile:: 67 IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM, 68 SectionKind Kind) const { 69 // Only global variables, not functions. 70 const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV); 71 if (!GVA) 72 return false; 73 74 if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) { 75 Type *Ty = GV->getType()->getElementType(); 76 return IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(Ty)); 77 } 78 79 return false; 80 } 81 82 const MCSection *HexagonTargetObjectFile:: 83 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, 84 Mangler *Mang, const TargetMachine &TM) const { 85 86 // Handle Small Section classification here. 87 if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind)) 88 return SmallBSSSection; 89 if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind)) 90 return SmallDataSection; 91 92 // Otherwise, we work the same as ELF. 93 return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM); 94 } 95
