lib/Target/XCore/XCoreTargetObjectFile.cpp

   1 //===-- XCoreTargetObjectFile.cpp - XCore object files --------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "XCoreTargetObjectFile.h"
  10 #include "XCoreSubtarget.h"
  11 #include "llvm/BinaryFormat/ELF.h"
  12 #include "llvm/IR/DataLayout.h"
  13 #include "llvm/MC/MCContext.h"
  14 #include "llvm/MC/MCSectionELF.h"
  15 #include "llvm/Target/TargetMachine.h"
  16
  17 using namespace llvm;
  18
  19
  20 void XCoreTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
  21   TargetLoweringObjectFileELF::Initialize(Ctx, TM);
  22
  23   BSSSection = Ctx.getELFSection(".dp.bss", ELF::SHT_NOBITS,
  24                                  ELF::SHF_ALLOC | ELF::SHF_WRITE |
  25                                      ELF::XCORE_SHF_DP_SECTION);
  26   BSSSectionLarge = Ctx.getELFSection(".dp.bss.large", ELF::SHT_NOBITS,
  27                                       ELF::SHF_ALLOC | ELF::SHF_WRITE |
  28                                           ELF::XCORE_SHF_DP_SECTION);
  29   DataSection = Ctx.getELFSection(".dp.data", ELF::SHT_PROGBITS,
  30                                   ELF::SHF_ALLOC | ELF::SHF_WRITE |
  31                                       ELF::XCORE_SHF_DP_SECTION);
  32   DataSectionLarge = Ctx.getELFSection(".dp.data.large", ELF::SHT_PROGBITS,
  33                                        ELF::SHF_ALLOC | ELF::SHF_WRITE |
  34                                            ELF::XCORE_SHF_DP_SECTION);
  35   DataRelROSection = Ctx.getELFSection(".dp.rodata", ELF::SHT_PROGBITS,
  36                                        ELF::SHF_ALLOC | ELF::SHF_WRITE |
  37                                            ELF::XCORE_SHF_DP_SECTION);
  38   DataRelROSectionLarge = Ctx.getELFSection(
  39       ".dp.rodata.large", ELF::SHT_PROGBITS,
  40       ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::XCORE_SHF_DP_SECTION);
  41   ReadOnlySection =
  42       Ctx.getELFSection(".cp.rodata", ELF::SHT_PROGBITS,
  43                         ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
  44   ReadOnlySectionLarge =
  45       Ctx.getELFSection(".cp.rodata.large", ELF::SHT_PROGBITS,
  46                         ELF::SHF_ALLOC | ELF::XCORE_SHF_CP_SECTION);
  47   MergeableConst4Section = Ctx.getELFSection(
  48       ".cp.rodata.cst4", ELF::SHT_PROGBITS,
  49       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 4, "");
  50   MergeableConst8Section = Ctx.getELFSection(
  51       ".cp.rodata.cst8", ELF::SHT_PROGBITS,
  52       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 8, "");
  53   MergeableConst16Section = Ctx.getELFSection(
  54       ".cp.rodata.cst16", ELF::SHT_PROGBITS,
  55       ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::XCORE_SHF_CP_SECTION, 16, "");
  56   CStringSection =
  57       Ctx.getELFSection(".cp.rodata.string", ELF::SHT_PROGBITS,
  58                         ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS |
  59                             ELF::XCORE_SHF_CP_SECTION);
  60   // TextSection       - see MObjectFileInfo.cpp
  61   // StaticCtorSection - see MObjectFileInfo.cpp
  62   // StaticDtorSection - see MObjectFileInfo.cpp
  63  }
  64
  65 static unsigned getXCoreSectionType(SectionKind K) {
  66   if (K.isBSS())
  67     return ELF::SHT_NOBITS;
  68   return ELF::SHT_PROGBITS;
  69 }
  70
  71 static unsigned getXCoreSectionFlags(SectionKind K, bool IsCPRel) {
  72   unsigned Flags = 0;
  73
  74   if (!K.isMetadata())
  75     Flags |= ELF::SHF_ALLOC;
  76
  77   if (K.isText())
  78     Flags |= ELF::SHF_EXECINSTR;
  79   else if (IsCPRel)
  80     Flags |= ELF::XCORE_SHF_CP_SECTION;
  81   else
  82     Flags |= ELF::XCORE_SHF_DP_SECTION;
  83
  84   if (K.isWriteable())
  85     Flags |= ELF::SHF_WRITE;
  86
  87   if (K.isMergeableCString() || K.isMergeableConst4() ||
  88       K.isMergeableConst8() || K.isMergeableConst16())
  89     Flags |= ELF::SHF_MERGE;
  90
  91   if (K.isMergeableCString())
  92     Flags |= ELF::SHF_STRINGS;
  93
  94   return Flags;
  95 }
  96
  97 MCSection *XCoreTargetObjectFile::getExplicitSectionGlobal(
  98     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
  99   StringRef SectionName = GO->getSection();
 100   // Infer section flags from the section name if we can.
 101   bool IsCPRel = SectionName.startswith(".cp.");
 102   if (IsCPRel && !Kind.isReadOnly())
 103     report_fatal_error("Using .cp. section for writeable object.");
 104   return getContext().getELFSection(SectionName, getXCoreSectionType(Kind),
 105                                     getXCoreSectionFlags(Kind, IsCPRel));
 106 }
 107
 108 MCSection *XCoreTargetObjectFile::SelectSectionForGlobal(
 109     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
 110
 111   bool UseCPRel = GO->hasLocalLinkage();
 112
 113   if (Kind.isText())                    return TextSection;
 114   if (UseCPRel) {
 115     if (Kind.isMergeable1ByteCString()) return CStringSection;
 116     if (Kind.isMergeableConst4())       return MergeableConst4Section;
 117     if (Kind.isMergeableConst8())       return MergeableConst8Section;
 118     if (Kind.isMergeableConst16())      return MergeableConst16Section;
 119   }
 120   Type *ObjType = GO->getValueType();
 121   auto &DL = GO->getParent()->getDataLayout();
 122   if (TM.getCodeModel() == CodeModel::Small || !ObjType->isSized() ||
 123       DL.getTypeAllocSize(ObjType) < CodeModelLargeSize) {
 124     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySection
 125                                                        : DataRelROSection;
 126     if (Kind.isBSS() || Kind.isCommon())return BSSSection;
 127     if (Kind.isData())
 128       return DataSection;
 129     if (Kind.isReadOnlyWithRel())       return DataRelROSection;
 130   } else {
 131     if (Kind.isReadOnly())              return UseCPRel? ReadOnlySectionLarge
 132                                                        : DataRelROSectionLarge;
 133     if (Kind.isBSS() || Kind.isCommon())return BSSSectionLarge;
 134     if (Kind.isData())
 135       return DataSectionLarge;
 136     if (Kind.isReadOnlyWithRel())       return DataRelROSectionLarge;
 137   }
 138
 139   assert((Kind.isThreadLocal() || Kind.isCommon()) && "Unknown section kind");
 140   report_fatal_error("Target does not support TLS or Common sections");
 141 }
 142
 143 MCSection *XCoreTargetObjectFile::getSectionForConstant(const DataLayout &DL,
 144                                                         SectionKind Kind,
 145                                                         const Constant *C,
 146                                                         unsigned &Align) const {
 147   if (Kind.isMergeableConst4())           return MergeableConst4Section;
 148   if (Kind.isMergeableConst8())           return MergeableConst8Section;
 149   if (Kind.isMergeableConst16())          return MergeableConst16Section;
 150   assert((Kind.isReadOnly() || Kind.isReadOnlyWithRel()) &&
 151          "Unknown section kind");
 152   // We assume the size of the object is never greater than CodeModelLargeSize.
 153   // To handle CodeModelLargeSize changes to AsmPrinter would be required.
 154   return ReadOnlySection;
 155 }