HexagonTargetObjectFile.cpp revision 79aa3417eb6f58d668aadfedf075240a41d35a26
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/Function.h" 18#include "llvm/GlobalVariable.h" 19#include "llvm/Target/TargetData.h" 20#include "llvm/DerivedTypes.h" 21#include "llvm/MC/MCContext.h" 22#include "llvm/Support/ELF.h" 23#include "llvm/Support/CommandLine.h" 24 25using namespace llvm; 26 27static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold", 28 cl::init(8), cl::Hidden); 29 30void 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. 46static 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. 51bool 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. 66bool HexagonTargetObjectFile:: 67IsGlobalInSmallSection(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.getTargetData()->getTypeAllocSize(Ty)); 77 } 78 79 return false; 80} 81 82const MCSection *HexagonTargetObjectFile:: 83SelectSectionForGlobal(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