include/llvm/Target/TargetLoweringObjectFile.h

   1 //===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- C++ -*-===//
   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 implements classes used to handle lowerings specific to common
  11 // object file formats.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
  16 #define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
  17
  18 #include "llvm/MC/SectionKind.h"
  19
  20 namespace llvm {
  21   class Mangler;
  22   class MCSection;
  23   class MCSectionMachO;
  24   class MCContext;
  25   class GlobalValue;
  26   class StringRef;
  27   class TargetMachine;
  28   class MCAsmInfo;
  29   class MCExpr;
  30
  31 class TargetLoweringObjectFile {
  32   MCContext *Ctx;
  33
  34   TargetLoweringObjectFile(const TargetLoweringObjectFile&); // DO NOT IMPLEMENT
  35   void operator=(const TargetLoweringObjectFile&);           // DO NOT IMPLEMENT
  36 protected:
  37
  38   TargetLoweringObjectFile();
  39
  40   /// TextSection - Section directive for standard text.
  41   ///
  42   const MCSection *TextSection;
  43
  44   /// DataSection - Section directive for standard data.
  45   ///
  46   const MCSection *DataSection;
  47
  48   /// BSSSection - Section that is default initialized to zero.
  49   const MCSection *BSSSection;
  50
  51   /// ReadOnlySection - Section that is readonly and can contain arbitrary
  52   /// initialized data.  Targets are not required to have a readonly section.
  53   /// If they don't, various bits of code will fall back to using the data
  54   /// section for constants.
  55   const MCSection *ReadOnlySection;
  56
  57   /// StaticCtorSection - This section contains the static constructor pointer
  58   /// list.
  59   const MCSection *StaticCtorSection;
  60
  61   /// StaticDtorSection - This section contains the static destructor pointer
  62   /// list.
  63   const MCSection *StaticDtorSection;
  64
  65   /// LSDASection - If exception handling is supported by the target, this is
  66   /// the section the Language Specific Data Area information is emitted to.
  67   const MCSection *LSDASection;
  68
  69   /// EHFrameSection - If exception handling is supported by the target, this is
  70   /// the section the EH Frame is emitted to.
  71   const MCSection *EHFrameSection;
  72
  73   // Dwarf sections for debug info.  If a target supports debug info, these must
  74   // be set.
  75   const MCSection *DwarfAbbrevSection;
  76   const MCSection *DwarfInfoSection;
  77   const MCSection *DwarfLineSection;
  78   const MCSection *DwarfFrameSection;
  79   const MCSection *DwarfPubNamesSection;
  80   const MCSection *DwarfPubTypesSection;
  81   const MCSection *DwarfDebugInlineSection;
  82   const MCSection *DwarfStrSection;
  83   const MCSection *DwarfLocSection;
  84   const MCSection *DwarfARangesSection;
  85   const MCSection *DwarfRangesSection;
  86   const MCSection *DwarfMacroInfoSection;
  87
  88 public:
  89
  90   MCContext &getContext() const { return *Ctx; }
  91
  92
  93   virtual ~TargetLoweringObjectFile();
  94
  95   /// Initialize - this method must be called before any actual lowering is
  96   /// done.  This specifies the current context for codegen, and gives the
  97   /// lowering implementations a chance to set up their default sections.
  98   virtual void Initialize(MCContext &ctx, const TargetMachine &TM) {
  99     Ctx = &ctx;
 100   }
 101
 102
 103   const MCSection *getTextSection() const { return TextSection; }
 104   const MCSection *getDataSection() const { return DataSection; }
 105   const MCSection *getBSSSection() const { return BSSSection; }
 106   const MCSection *getStaticCtorSection() const { return StaticCtorSection; }
 107   const MCSection *getStaticDtorSection() const { return StaticDtorSection; }
 108   const MCSection *getLSDASection() const { return LSDASection; }
 109   const MCSection *getEHFrameSection() const { return EHFrameSection; }
 110   const MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
 111   const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
 112   const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
 113   const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
 114   const MCSection *getDwarfPubNamesSection() const{return DwarfPubNamesSection;}
 115   const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
 116   const MCSection *getDwarfDebugInlineSection() const {
 117     return DwarfDebugInlineSection;
 118   }
 119   const MCSection *getDwarfStrSection() const { return DwarfStrSection; }
 120   const MCSection *getDwarfLocSection() const { return DwarfLocSection; }
 121   const MCSection *getDwarfARangesSection() const { return DwarfARangesSection;}
 122   const MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
 123   const MCSection *getDwarfMacroInfoSection() const {
 124     return DwarfMacroInfoSection;
 125   }
 126
 127   /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
 128   /// decide not to emit the UsedDirective for some symbols in llvm.used.
 129   /// FIXME: REMOVE this (rdar://7071300)
 130   virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
 131                                           Mangler *) const {
 132     return GV != 0;
 133   }
 134
 135   /// getSectionForConstant - Given a constant with the SectionKind, return a
 136   /// section that it should be placed in.
 137   virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
 138
 139   /// getKindForGlobal - Classify the specified global variable into a set of
 140   /// target independent categories embodied in SectionKind.
 141   static SectionKind getKindForGlobal(const GlobalValue *GV,
 142                                       const TargetMachine &TM);
 143
 144   /// SectionForGlobal - This method computes the appropriate section to emit
 145   /// the specified global variable or function definition.  This should not
 146   /// be passed external (or available externally) globals.
 147   const MCSection *SectionForGlobal(const GlobalValue *GV,
 148                                     SectionKind Kind, Mangler *Mang,
 149                                     const TargetMachine &TM) const;
 150
 151   /// SectionForGlobal - This method computes the appropriate section to emit
 152   /// the specified global variable or function definition.  This should not
 153   /// be passed external (or available externally) globals.
 154   const MCSection *SectionForGlobal(const GlobalValue *GV,
 155                                     Mangler *Mang,
 156                                     const TargetMachine &TM) const {
 157     return SectionForGlobal(GV, getKindForGlobal(GV, TM), Mang, TM);
 158   }
 159
 160
 161
 162   /// getExplicitSectionGlobal - Targets should implement this method to assign
 163   /// a section to globals with an explicit section specfied.  The
 164   /// implementation of this method can assume that GV->hasSection() is true.
 165   virtual const MCSection *
 166   getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 167                            Mangler *Mang, const TargetMachine &TM) const = 0;
 168
 169   /// getSpecialCasedSectionGlobals - Allow the target to completely override
 170   /// section assignment of a global.
 171   virtual const MCSection *
 172   getSpecialCasedSectionGlobals(const GlobalValue *GV, Mangler *Mang,
 173                                 SectionKind Kind) const {
 174     return 0;
 175   }
 176
 177   /// getSymbolForDwarfGlobalReference - Return an MCExpr to use for a
 178   /// pc-relative reference to the specified global variable from exception
 179   /// handling information.  In addition to the symbol, this returns
 180   /// by-reference:
 181   ///
 182   /// IsIndirect - True if the returned symbol is actually a stub that contains
 183   ///    the address of the symbol, false if the symbol is the global itself.
 184   ///
 185   /// IsPCRel - True if the symbol reference is already pc-relative, false if
 186   ///    the caller needs to subtract off the address of the reference from the
 187   ///    symbol.
 188   ///
 189   virtual const MCExpr *
 190   getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 191                                    bool &IsIndirect, bool &IsPCRel) const;
 192
 193 protected:
 194   virtual const MCSection *
 195   SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 196                          Mangler *Mang, const TargetMachine &TM) const;
 197 };
 198
 199
 200
 201
 202 class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
 203   mutable void *UniquingMap;
 204 protected:
 205   /// TLSDataSection - Section directive for Thread Local data.
 206   ///
 207   const MCSection *TLSDataSection;        // Defaults to ".tdata".
 208
 209   /// TLSBSSSection - Section directive for Thread Local uninitialized data.
 210   /// Null if this target doesn't support a BSS section.
 211   ///
 212   const MCSection *TLSBSSSection;         // Defaults to ".tbss".
 213
 214   const MCSection *DataRelSection;
 215   const MCSection *DataRelLocalSection;
 216   const MCSection *DataRelROSection;
 217   const MCSection *DataRelROLocalSection;
 218
 219   const MCSection *MergeableConst4Section;
 220   const MCSection *MergeableConst8Section;
 221   const MCSection *MergeableConst16Section;
 222
 223 protected:
 224   const MCSection *getELFSection(StringRef Section, unsigned Type,
 225                                  unsigned Flags, SectionKind Kind,
 226                                  bool IsExplicit = false) const;
 227 public:
 228   TargetLoweringObjectFileELF() : UniquingMap(0) {}
 229   ~TargetLoweringObjectFileELF();
 230
 231   virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
 232
 233   /// getSectionForConstant - Given a constant with the SectionKind, return a
 234   /// section that it should be placed in.
 235   virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
 236
 237
 238   virtual const MCSection *
 239   getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 240                            Mangler *Mang, const TargetMachine &TM) const;
 241
 242   virtual const MCSection *
 243   SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 244                          Mangler *Mang, const TargetMachine &TM) const;
 245 };
 246
 247
 248
 249 class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
 250   mutable void *UniquingMap;
 251
 252   const MCSection *CStringSection;
 253   const MCSection *UStringSection;
 254   const MCSection *TextCoalSection;
 255   const MCSection *ConstTextCoalSection;
 256   const MCSection *ConstDataCoalSection;
 257   const MCSection *ConstDataSection;
 258   const MCSection *DataCoalSection;
 259   const MCSection *FourByteConstantSection;
 260   const MCSection *EightByteConstantSection;
 261   const MCSection *SixteenByteConstantSection;
 262
 263   const MCSection *LazySymbolPointerSection;
 264   const MCSection *NonLazySymbolPointerSection;
 265 public:
 266   TargetLoweringObjectFileMachO() : UniquingMap(0) {}
 267   ~TargetLoweringObjectFileMachO();
 268
 269   virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
 270
 271   virtual const MCSection *
 272   SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 273                          Mangler *Mang, const TargetMachine &TM) const;
 274
 275   virtual const MCSection *
 276   getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 277                            Mangler *Mang, const TargetMachine &TM) const;
 278
 279   virtual const MCSection *getSectionForConstant(SectionKind Kind) const;
 280
 281   /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
 282   /// decide not to emit the UsedDirective for some symbols in llvm.used.
 283   /// FIXME: REMOVE this (rdar://7071300)
 284   virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
 285                                           Mangler *) const;
 286
 287   /// getMachOSection - Return the MCSection for the specified mach-o section.
 288   /// This requires the operands to be valid.
 289   const MCSectionMachO *getMachOSection(const StringRef &Segment,
 290                                         const StringRef &Section,
 291                                         unsigned TypeAndAttributes,
 292                                         SectionKind K) const {
 293     return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
 294   }
 295   const MCSectionMachO *getMachOSection(const StringRef &Segment,
 296                                         const StringRef &Section,
 297                                         unsigned TypeAndAttributes,
 298                                         unsigned Reserved2,
 299                                         SectionKind K) const;
 300
 301   /// getTextCoalSection - Return the "__TEXT,__textcoal_nt" section we put weak
 302   /// symbols into.
 303   const MCSection *getTextCoalSection() const {
 304     return TextCoalSection;
 305   }
 306
 307   /// getLazySymbolPointerSection - Return the section corresponding to
 308   /// the .lazy_symbol_pointer directive.
 309   const MCSection *getLazySymbolPointerSection() const {
 310     return LazySymbolPointerSection;
 311   }
 312
 313   /// getNonLazySymbolPointerSection - Return the section corresponding to
 314   /// the .non_lazy_symbol_pointer directive.
 315   const MCSection *getNonLazySymbolPointerSection() const {
 316     return NonLazySymbolPointerSection;
 317   }
 318
 319   /// getSymbolForDwarfGlobalReference - The mach-o version of this method
 320   /// defaults to returning a stub reference.
 321   virtual const MCExpr *
 322   getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 323                                    bool &IsIndirect, bool &IsPCRel) const;
 324 };
 325
 326
 327
 328 class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
 329   mutable void *UniquingMap;
 330 public:
 331   TargetLoweringObjectFileCOFF() : UniquingMap(0) {}
 332   ~TargetLoweringObjectFileCOFF();
 333
 334   virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
 335
 336   virtual const MCSection *
 337   getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 338                            Mangler *Mang, const TargetMachine &TM) const;
 339
 340   virtual const MCSection *
 341   SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 342                          Mangler *Mang, const TargetMachine &TM) const;
 343
 344   /// getCOFFSection - Return the MCSection for the specified COFF section.
 345   /// FIXME: Switch this to a semantic view eventually.
 346   const MCSection *getCOFFSection(const char *Name, bool isDirective,
 347                                   SectionKind K) const;
 348 };
 349
 350 } // end namespace llvm
 351
 352 #endif