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/BinaryFormat/ELF.h"
  13 #include "llvm/IR/DataLayout.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCSectionELF.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 = Ctx.getELFSection(".dp.bss", ELF::SHT_NOBITS,
  25                                  ELF::SHF_ALLOC | ELF::SHF_WRITE |
  26                                      ELF::XCORE_SHF_DP_SECTION);
  27   BSSSectionLarge = Ctx.getELFSection(".dp.bss.large", ELF::SHT_NOBITS,
  28                                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  29                                           ELF::XCORE_SHF_DP_SECTION);
  30   DataSection = Ctx.getELFSection(".dp.data", ELF::SHT_PROGBITS,
  31                                   ELF::SHF_ALLOC | ELF::SHF_WRITE |
  32                                       ELF::XCORE_SHF_DP_SECTION);
  33   DataSectionLarge = Ctx.getELFSection(".dp.data.large", ELF::SHT_PROGBITS,
  34                                        ELF::SHF_ALLOC | ELF::SHF_WRITE |
  35                                            ELF::XCORE_SHF_DP_SECTION);
  36   DataRelROSection = Ctx.getELFSection(".dp.rodata", ELF::SHT_PROGBITS,
  37                                        ELF::SHF_ALLOC | ELF::SHF_WRITE |
  38                                            ELF::XCORE_SHF_DP_SECTION);
  39   DataRelROSectionLarge = Ctx.getELFSection(
  40       ".dp.rodata.large", ELF::SHT_PROGBITS,
  41       ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::XCORE_SHF_DP_SECTION);
  42   ReadOnlySection =
  43       Ctx.getELFSection(".cp.rodata", ELF::SHT_PROGBITS,
  44                         ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
  45   ReadOnlySectionLarge =
  46       Ctx.getELFSection(".cp.rodata.large", ELF::SHT_PROGBITS,
  47                         ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
  48   MergeableConst4Section = Ctx.getELFSection(
  49       ".cp.rodata.cst4", ELF::SHT_PROGBITS,
  50       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 4, "");
  51   MergeableConst8Section = Ctx.getELFSection(
  52       ".cp.rodata.cst8", ELF::SHT_PROGBITS,
  53       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 8, "");
  54   MergeableConst16Section = Ctx.getELFSection(
  55       ".cp.rodata.cst16", ELF::SHT_PROGBITS,
  56       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 16, "");
  57   CStringSection =
  58       Ctx.getELFSection(".cp.rodata.string", ELF::SHT_PROGBITS,
  59                         ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS |
  60                             ELF::XCORE_SHF_CP_SECTION);
  61   // TextSection       - see MObjectFileInfo.cpp
  62   // StaticCtorSection - see MObjectFileInfo.cpp
  63   // StaticDtorSection - see MObjectFileInfo.cpp
  64  }
  65
  66 static unsigned getXCoreSectionType(SectionKind K) {
  67   if (K.isBSS())
  68     return ELF::SHT_NOBITS;
  69   return ELF::SHT_PROGBITS;
  70 }
  71
  72 static unsigned getXCoreSectionFlags(SectionKind K, bool IsCPRel) {
  73   unsigned Flags = 0;
  74
  75   if (!K.isMetadata())
  76     Flags |= ELF::SHF_ALLOC;
  77
  78   if (K.isText())
  79     Flags |= ELF::SHF_EXECINSTR;
  80   else if (IsCPRel)
  81     Flags |= ELF::XCORE_SHF_CP_SECTION;
  82   else
  83     Flags |= ELF::XCORE_SHF_DP_SECTION;
  84
  85   if (K.isWriteable())
  86     Flags |= ELF::SHF_WRITE;
  87
  88   if (K.isMergeableCString() || K.isMergeableConst4() ||
  89       K.isMergeableConst8() || K.isMergeableConst16())
  90     Flags |= ELF::SHF_MERGE;
  91
  92   if (K.isMergeableCString())
  93     Flags |= ELF::SHF_STRINGS;
  94
  95   return Flags;
  96 }
  97
  98 MCSection *XCoreTargetObjectFile::getExplicitSectionGlobal(
  99     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
 100   StringRef SectionName = GO->getSection();
 101   // Infer section flags from the section name if we can.
 102   bool IsCPRel = SectionName.startswith(".cp.");
 103   if (IsCPRel && !Kind.isReadOnly())
 104     report_fatal_error("Using .cp. section for writeable object.");
 105   return getContext().getELFSection(SectionName, getXCoreSectionType(Kind),
 106                                     getXCoreSectionFlags(Kind, IsCPRel));
 107 }
 108
 109 MCSection *XCoreTargetObjectFile::SelectSectionForGlobal(
 110     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
 111
 112   bool UseCPRel = GO->hasLocalLinkage();
 113
 114   if (Kind.isText())                    return TextSection;
 115   if (UseCPRel) {
 116     if (Kind.isMergeable1ByteCString()) return CStringSection;
 117     if (Kind.isMergeableConst4())       return MergeableConst4Section;
 118     if (Kind.isMergeableConst8())       return MergeableConst8Section;
 119     if (Kind.isMergeableConst16())      return MergeableConst16Section;
 120   }
 121   Type *ObjType = GO->getValueType();
 122   auto &DL = GO->getParent()->getDataLayout();
 123   if (TM.getCodeModel() == CodeModel::Small || !ObjType->isSized() ||
 124       DL.getTypeAllocSize(ObjType) < CodeModelLargeSize) {
 125     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySection
 126                                                        : DataRelROSection;
 127     if (Kind.isBSS() || Kind.isCommon())return BSSSection;
 128     if (Kind.isData())
 129       return DataSection;
 130     if (Kind.isReadOnlyWithRel())       return DataRelROSection;
 131   } else {
 132     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySectionLarge
 133                                                        : DataRelROSectionLarge;
 134     if (Kind.isBSS() || Kind.isCommon())return BSSSectionLarge;
 135     if (Kind.isData())
 136       return DataSectionLarge;
 137     if (Kind.isReadOnlyWithRel())       return DataRelROSectionLarge;
 138   }
 139
 140   assert((Kind.isThreadLocal() || Kind.isCommon()) && "Unknown section kind");
 141   report_fatal_error("Target does not support TLS or Common sections");
 142 }
 143
 144 MCSection *XCoreTargetObjectFile::getSectionForConstant(const DataLayout &DL,
 145                                                         SectionKind Kind,
 146                                                         const Constant *C,
 147                                                         unsigned &Align) const {
 148   if (Kind.isMergeableConst4())           return MergeableConst4Section;
 149   if (Kind.isMergeableConst8())           return MergeableConst8Section;
 150   if (Kind.isMergeableConst16())          return MergeableConst16Section;
 151   assert((Kind.isReadOnly() || Kind.isReadOnlyWithRel()) &&
 152          "Unknown section kind");
 153   // We assume the size of the object is never greater than CodeModelLargeSize.
 154   // To handle CodeModelLargeSize changes to AsmPrinter would be required.
 155   return ReadOnlySection;
 156 }