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 cl::desc("The maximum size of an object in the sdata section")); 30 31 void HexagonTargetObjectFile::Initialize(MCContext &Ctx, 32 const TargetMachine &TM) { 33 TargetLoweringObjectFileELF::Initialize(Ctx, TM); 34 35 36 SmallDataSection = 37 getContext().getELFSection(".sdata", ELF::SHT_PROGBITS, 38 ELF::SHF_WRITE | ELF::SHF_ALLOC, 39 SectionKind::getDataRel()); 40 SmallBSSSection = 41 getContext().getELFSection(".sbss", ELF::SHT_NOBITS, 42 ELF::SHF_WRITE | ELF::SHF_ALLOC, 43 SectionKind::getBSS()); 44 } 45 46 // sdata/sbss support taken largely from the MIPS Backend. 47 static bool IsInSmallSection(uint64_t Size) { 48 return Size > 0 && Size <= (uint64_t)SmallDataThreshold; 49 } 50 51 bool HexagonTargetObjectFile::IsSmallDataEnabled () const { 52 return SmallDataThreshold > 0; 53 } 54 55 /// IsGlobalInSmallSection - Return true if this global value should be 56 /// placed into small data/bss section. 57 bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV, 58 const TargetMachine &TM) const { 59 // If the primary definition of this global value is outside the current 60 // translation unit or the global value is available for inspection but not 61 // emission, then do nothing. 62 if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) 63 return false; 64 65 // Otherwise, Check if GV should be in sdata/sbss, when normally it would end 66 // up in getKindForGlobal(GV, TM). 67 return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM)); 68 } 69 70 /// IsGlobalInSmallSection - Return true if this global value should be 71 /// placed into small data/bss section. 72 bool HexagonTargetObjectFile:: 73 IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM, 74 SectionKind Kind) const { 75 // Only global variables, not functions. 76 const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV); 77 if (!GVA) 78 return false; 79 80 if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) { 81 Type *Ty = GV->getType()->getElementType(); 82 return IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(Ty)); 83 } 84 85 return false; 86 } 87 88 const MCSection * 89 HexagonTargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV, 90 SectionKind Kind, Mangler &Mang, 91 const TargetMachine &TM) const { 92 93 // Handle Small Section classification here. 94 if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind)) 95 return SmallBSSSection; 96 if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind)) 97 return SmallDataSection; 98 99 // Otherwise, we work the same as ELF. 100 return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM); 101 } 102
