lib/Target/XCore/XCoreTargetObjectFile.cpp

   1 //===-- XCoreTargetObjectFile.cpp - XCore object files --------------------===//
   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 #include "XCoreTargetObjectFile.h"
  11 #include "XCoreSubtarget.h"
  12 #include "llvm/IR/DataLayout.h"
  13 #include "llvm/MC/MCContext.h"
  14 #include "llvm/MC/MCSectionELF.h"
  15 #include "llvm/Support/ELF.h"
  16 #include "llvm/Target/TargetMachine.h"
  17
  18 using namespace llvm;
  19
  20
  21 void XCoreTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
  22   TargetLoweringObjectFileELF::Initialize(Ctx, TM);
  23
  24   BSSSection =
  25     Ctx.getELFSection(".dp.bss", ELF::SHT_NOBITS,
  26                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  27                       ELF::XCORE_SHF_DP_SECTION,
  28                       SectionKind::getBSS());
  29   BSSSectionLarge =
  30     Ctx.getELFSection(".dp.bss.large", ELF::SHT_NOBITS,
  31                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  32                       ELF::XCORE_SHF_DP_SECTION,
  33                       SectionKind::getBSS());
  34   DataSection =
  35     Ctx.getELFSection(".dp.data", ELF::SHT_PROGBITS,
  36                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  37                       ELF::XCORE_SHF_DP_SECTION,
  38                       SectionKind::getDataRel());
  39   DataSectionLarge =
  40     Ctx.getELFSection(".dp.data.large", ELF::SHT_PROGBITS,
  41                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  42                       ELF::XCORE_SHF_DP_SECTION,
  43                       SectionKind::getDataRel());
  44   DataRelROSection =
  45     Ctx.getELFSection(".dp.rodata", ELF::SHT_PROGBITS,
  46                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  47                       ELF::XCORE_SHF_DP_SECTION,
  48                       SectionKind::getReadOnlyWithRel());
  49   DataRelROSectionLarge =
  50     Ctx.getELFSection(".dp.rodata.large", ELF::SHT_PROGBITS,
  51                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  52                       ELF::XCORE_SHF_DP_SECTION,
  53                       SectionKind::getReadOnlyWithRel());
  54   ReadOnlySection =
  55     Ctx.getELFSection(".cp.rodata", ELF::SHT_PROGBITS,
  56                       ELF::SHF_ALLOC |
  57                       ELF::XCORE_SHF_CP_SECTION,
  58                       SectionKind::getReadOnlyWithRel());
  59   ReadOnlySectionLarge =
  60     Ctx.getELFSection(".cp.rodata.large", ELF::SHT_PROGBITS,
  61                       ELF::SHF_ALLOC |
  62                       ELF::XCORE_SHF_CP_SECTION,
  63                       SectionKind::getReadOnlyWithRel());
  64   MergeableConst4Section =
  65     Ctx.getELFSection(".cp.rodata.cst4", ELF::SHT_PROGBITS,
  66                       ELF::SHF_ALLOC | ELF::SHF_MERGE |
  67                       ELF::XCORE_SHF_CP_SECTION,
  68                       SectionKind::getMergeableConst4());
  69   MergeableConst8Section =
  70     Ctx.getELFSection(".cp.rodata.cst8", ELF::SHT_PROGBITS,
  71                       ELF::SHF_ALLOC | ELF::SHF_MERGE |
  72                       ELF::XCORE_SHF_CP_SECTION,
  73                       SectionKind::getMergeableConst8());
  74   MergeableConst16Section =
  75     Ctx.getELFSection(".cp.rodata.cst16", ELF::SHT_PROGBITS,
  76                       ELF::SHF_ALLOC | ELF::SHF_MERGE |
  77                       ELF::XCORE_SHF_CP_SECTION,
  78                       SectionKind::getMergeableConst16());
  79   CStringSection =
  80     Ctx.getELFSection(".cp.rodata.string", ELF::SHT_PROGBITS,
  81                       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS |
  82                       ELF::XCORE_SHF_CP_SECTION,
  83                       SectionKind::getReadOnlyWithRel());
  84   // TextSection       - see MObjectFileInfo.cpp
  85   // StaticCtorSection - see MObjectFileInfo.cpp
  86   // StaticDtorSection - see MObjectFileInfo.cpp
  87  }
  88
  89 static unsigned getXCoreSectionType(SectionKind K) {
  90   if (K.isBSS())
  91     return ELF::SHT_NOBITS;
  92   return ELF::SHT_PROGBITS;
  93 }
  94
  95 static unsigned getXCoreSectionFlags(SectionKind K, bool IsCPRel) {
  96   unsigned Flags = 0;
  97
  98   if (!K.isMetadata())
  99     Flags |= ELF::SHF_ALLOC;
 100
 101   if (K.isText())
 102     Flags |= ELF::SHF_EXECINSTR;
 103   else if (IsCPRel)
 104     Flags |= ELF::XCORE_SHF_CP_SECTION;
 105   else
 106     Flags |= ELF::XCORE_SHF_DP_SECTION;
 107
 108   if (K.isWriteable())
 109     Flags |= ELF::SHF_WRITE;
 110
 111   if (K.isMergeableCString() || K.isMergeableConst4() ||
 112       K.isMergeableConst8() || K.isMergeableConst16())
 113     Flags |= ELF::SHF_MERGE;
 114
 115   if (K.isMergeableCString())
 116     Flags |= ELF::SHF_STRINGS;
 117
 118   return Flags;
 119 }
 120
 121 const MCSection *
 122 XCoreTargetObjectFile::getExplicitSectionGlobal(const GlobalValue *GV,
 123                                                 SectionKind Kind, Mangler &Mang,
 124                                                 const TargetMachine &TM) const {
 125   StringRef SectionName = GV->getSection();
 126   // Infer section flags from the section name if we can.
 127   bool IsCPRel = SectionName.startswith(".cp.");
 128   if (IsCPRel && !Kind.isReadOnly())
 129     report_fatal_error("Using .cp. section for writeable object.");
 130   return getContext().getELFSection(SectionName, getXCoreSectionType(Kind),
 131                                     getXCoreSectionFlags(Kind, IsCPRel), Kind);
 132 }
 133
 134 const MCSection *XCoreTargetObjectFile::
 135 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
 136                        const TargetMachine &TM) const{
 137
 138   bool UseCPRel = GV->isLocalLinkage(GV->getLinkage());
 139
 140   if (Kind.isText())                    return TextSection;
 141   if (UseCPRel) {
 142     if (Kind.isMergeable1ByteCString()) return CStringSection;
 143     if (Kind.isMergeableConst4())       return MergeableConst4Section;
 144     if (Kind.isMergeableConst8())       return MergeableConst8Section;
 145     if (Kind.isMergeableConst16())      return MergeableConst16Section;
 146   }
 147   Type *ObjType = GV->getType()->getPointerElementType();
 148   if (TM.getCodeModel() == CodeModel::Small || !ObjType->isSized() ||
 149       TM.getSubtargetImpl()->getDataLayout()->getTypeAllocSize(ObjType) <
 150           CodeModelLargeSize) {
 151     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySection
 152                                                        : DataRelROSection;
 153     if (Kind.isBSS() || Kind.isCommon())return BSSSection;
 154     if (Kind.isDataRel())               return DataSection;
 155     if (Kind.isReadOnlyWithRel())       return DataRelROSection;
 156   } else {
 157     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySectionLarge
 158                                                        : DataRelROSectionLarge;
 159     if (Kind.isBSS() || Kind.isCommon())return BSSSectionLarge;
 160     if (Kind.isDataRel())               return DataSectionLarge;
 161     if (Kind.isReadOnlyWithRel())       return DataRelROSectionLarge;
 162   }
 163
 164   assert((Kind.isThreadLocal() || Kind.isCommon()) && "Unknown section kind");
 165   report_fatal_error("Target does not support TLS or Common sections");
 166 }
 167
 168 const MCSection *
 169 XCoreTargetObjectFile::getSectionForConstant(SectionKind Kind,
 170                                              const Constant *C) const {
 171   if (Kind.isMergeableConst4())           return MergeableConst4Section;
 172   if (Kind.isMergeableConst8())           return MergeableConst8Section;
 173   if (Kind.isMergeableConst16())          return MergeableConst16Section;
 174   assert((Kind.isReadOnly() || Kind.isReadOnlyWithRel()) &&
 175          "Unknown section kind");
 176   // We assume the size of the object is never greater than CodeModelLargeSize.
 177   // To handle CodeModelLargeSize changes to AsmPrinter would be required.
 178   return ReadOnlySection;
 179 }