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