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      1 //===-- llvm/MC/MCObjectFileInfo.h - Object File Info -----------*- C++ -*-===//
      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 // This file describes common object file formats.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef LLVM_MC_MCOBJECTFILEINFO_H
     14 #define LLVM_MC_MCOBJECTFILEINFO_H
     15 
     16 #include "llvm/ADT/DenseMap.h"
     17 #include "llvm/ADT/Triple.h"
     18 #include "llvm/MC/MCSymbol.h"
     19 #include "llvm/Support/CodeGen.h"
     20 #include "llvm/Support/VersionTuple.h"
     21 
     22 namespace llvm {
     23 class MCContext;
     24 class MCSection;
     25 
     26 class MCObjectFileInfo {
     27 protected:
     28   /// True if .comm supports alignment.  This is a hack for as long as we
     29   /// support 10.4 Tiger, whose assembler doesn't support alignment on comm.
     30   bool CommDirectiveSupportsAlignment = false;
     31 
     32   /// True if target object file supports a weak_definition of constant 0 for an
     33   /// omitted EH frame.
     34   bool SupportsWeakOmittedEHFrame = false;
     35 
     36   /// True if the target object file supports emitting a compact unwind section
     37   /// without an associated EH frame section.
     38   bool SupportsCompactUnwindWithoutEHFrame = false;
     39 
     40   /// OmitDwarfIfHaveCompactUnwind - True if the target object file
     41   /// supports having some functions with compact unwind and other with
     42   /// dwarf unwind.
     43   bool OmitDwarfIfHaveCompactUnwind = false;
     44 
     45   /// FDE CFI encoding. Controls the encoding of the begin label in the
     46   /// .eh_frame section. Unlike the LSDA encoding, personality encoding, and
     47   /// type encodings, this is something that the assembler just "knows" about
     48   /// its target
     49   unsigned FDECFIEncoding = 0;
     50 
     51   /// Compact unwind encoding indicating that we should emit only an EH frame.
     52   unsigned CompactUnwindDwarfEHFrameOnly = 0;
     53 
     54   /// Section directive for standard text.
     55   MCSection *TextSection = nullptr;
     56 
     57   /// Section directive for standard data.
     58   MCSection *DataSection = nullptr;
     59 
     60   /// Section that is default initialized to zero.
     61   MCSection *BSSSection = nullptr;
     62 
     63   /// Section that is readonly and can contain arbitrary initialized data.
     64   /// Targets are not required to have a readonly section. If they don't,
     65   /// various bits of code will fall back to using the data section for
     66   /// constants.
     67   MCSection *ReadOnlySection = nullptr;
     68 
     69   /// If exception handling is supported by the target, this is the section the
     70   /// Language Specific Data Area information is emitted to.
     71   MCSection *LSDASection = nullptr;
     72 
     73   /// If exception handling is supported by the target and the target can
     74   /// support a compact representation of the CIE and FDE, this is the section
     75   /// to emit them into.
     76   MCSection *CompactUnwindSection = nullptr;
     77 
     78   // Dwarf sections for debug info.  If a target supports debug info, these must
     79   // be set.
     80   MCSection *DwarfAbbrevSection = nullptr;
     81   MCSection *DwarfInfoSection = nullptr;
     82   MCSection *DwarfLineSection = nullptr;
     83   MCSection *DwarfLineStrSection = nullptr;
     84   MCSection *DwarfFrameSection = nullptr;
     85   MCSection *DwarfPubTypesSection = nullptr;
     86   const MCSection *DwarfDebugInlineSection = nullptr;
     87   MCSection *DwarfStrSection = nullptr;
     88   MCSection *DwarfLocSection = nullptr;
     89   MCSection *DwarfARangesSection = nullptr;
     90   MCSection *DwarfRangesSection = nullptr;
     91   MCSection *DwarfMacinfoSection = nullptr;
     92   MCSection *DwarfMacroSection = nullptr;
     93   // The pubnames section is no longer generated by default.  The generation
     94   // can be enabled by a compiler flag.
     95   MCSection *DwarfPubNamesSection = nullptr;
     96 
     97   /// Accelerator table sections. DwarfDebugNamesSection is the DWARF v5
     98   /// accelerator table, while DwarfAccelNamesSection, DwarfAccelObjCSection,
     99   /// DwarfAccelNamespaceSection, DwarfAccelTypesSection are pre-DWARF v5
    100   /// extensions.
    101   MCSection *DwarfDebugNamesSection = nullptr;
    102   MCSection *DwarfAccelNamesSection = nullptr;
    103   MCSection *DwarfAccelObjCSection = nullptr;
    104   MCSection *DwarfAccelNamespaceSection = nullptr;
    105   MCSection *DwarfAccelTypesSection = nullptr;
    106 
    107   // These are used for the Fission separate debug information files.
    108   MCSection *DwarfInfoDWOSection = nullptr;
    109   MCSection *DwarfTypesDWOSection = nullptr;
    110   MCSection *DwarfAbbrevDWOSection = nullptr;
    111   MCSection *DwarfStrDWOSection = nullptr;
    112   MCSection *DwarfLineDWOSection = nullptr;
    113   MCSection *DwarfLocDWOSection = nullptr;
    114   MCSection *DwarfStrOffDWOSection = nullptr;
    115   MCSection *DwarfMacinfoDWOSection = nullptr;
    116   MCSection *DwarfMacroDWOSection = nullptr;
    117 
    118   /// The DWARF v5 string offset and address table sections.
    119   MCSection *DwarfStrOffSection = nullptr;
    120   MCSection *DwarfAddrSection = nullptr;
    121   /// The DWARF v5 range list section.
    122   MCSection *DwarfRnglistsSection = nullptr;
    123   /// The DWARF v5 locations list section.
    124   MCSection *DwarfLoclistsSection = nullptr;
    125 
    126   /// The DWARF v5 range and location list sections for fission.
    127   MCSection *DwarfRnglistsDWOSection = nullptr;
    128   MCSection *DwarfLoclistsDWOSection = nullptr;
    129 
    130   // These are for Fission DWP files.
    131   MCSection *DwarfCUIndexSection = nullptr;
    132   MCSection *DwarfTUIndexSection = nullptr;
    133 
    134   /// Section for newer gnu pubnames.
    135   MCSection *DwarfGnuPubNamesSection = nullptr;
    136   /// Section for newer gnu pubtypes.
    137   MCSection *DwarfGnuPubTypesSection = nullptr;
    138 
    139   // Section for Swift AST
    140   MCSection *DwarfSwiftASTSection = nullptr;
    141 
    142   MCSection *COFFDebugSymbolsSection = nullptr;
    143   MCSection *COFFDebugTypesSection = nullptr;
    144   MCSection *COFFGlobalTypeHashesSection = nullptr;
    145 
    146   /// Extra TLS Variable Data section.
    147   ///
    148   /// If the target needs to put additional information for a TLS variable,
    149   /// it'll go here.
    150   MCSection *TLSExtraDataSection = nullptr;
    151 
    152   /// Section directive for Thread Local data. ELF, MachO, COFF, and Wasm.
    153   MCSection *TLSDataSection = nullptr; // Defaults to ".tdata".
    154 
    155   /// Section directive for Thread Local uninitialized data.
    156   ///
    157   /// Null if this target doesn't support a BSS section. ELF and MachO only.
    158   MCSection *TLSBSSSection = nullptr; // Defaults to ".tbss".
    159 
    160   /// StackMap section.
    161   MCSection *StackMapSection = nullptr;
    162 
    163   /// FaultMap section.
    164   MCSection *FaultMapSection = nullptr;
    165 
    166   /// Remarks section.
    167   MCSection *RemarksSection = nullptr;
    168 
    169   /// EH frame section.
    170   ///
    171   /// It is initialized on demand so it can be overwritten (with uniquing).
    172   MCSection *EHFrameSection = nullptr;
    173 
    174   /// Section containing metadata on function stack sizes.
    175   MCSection *StackSizesSection = nullptr;
    176 
    177   /// Section for pseudo probe information used by AutoFDO
    178   MCSection *PseudoProbeSection = nullptr;
    179   MCSection *PseudoProbeDescSection = nullptr;
    180 
    181   // ELF specific sections.
    182   MCSection *DataRelROSection = nullptr;
    183   MCSection *MergeableConst4Section = nullptr;
    184   MCSection *MergeableConst8Section = nullptr;
    185   MCSection *MergeableConst16Section = nullptr;
    186   MCSection *MergeableConst32Section = nullptr;
    187 
    188   // MachO specific sections.
    189 
    190   /// Section for thread local structure information.
    191   ///
    192   /// Contains the source code name of the variable, visibility and a pointer to
    193   /// the initial value (.tdata or .tbss).
    194   MCSection *TLSTLVSection = nullptr; // Defaults to ".tlv".
    195 
    196   /// Section for thread local data initialization functions.
    197    // Defaults to ".thread_init_func".
    198   const MCSection *TLSThreadInitSection = nullptr;
    199 
    200   MCSection *CStringSection = nullptr;
    201   MCSection *UStringSection = nullptr;
    202   MCSection *TextCoalSection = nullptr;
    203   MCSection *ConstTextCoalSection = nullptr;
    204   MCSection *ConstDataSection = nullptr;
    205   MCSection *DataCoalSection = nullptr;
    206   MCSection *ConstDataCoalSection = nullptr;
    207   MCSection *DataCommonSection = nullptr;
    208   MCSection *DataBSSSection = nullptr;
    209   MCSection *FourByteConstantSection = nullptr;
    210   MCSection *EightByteConstantSection = nullptr;
    211   MCSection *SixteenByteConstantSection = nullptr;
    212   MCSection *LazySymbolPointerSection = nullptr;
    213   MCSection *NonLazySymbolPointerSection = nullptr;
    214   MCSection *ThreadLocalPointerSection = nullptr;
    215 
    216   /// COFF specific sections.
    217   MCSection *DrectveSection = nullptr;
    218   MCSection *PDataSection = nullptr;
    219   MCSection *XDataSection = nullptr;
    220   MCSection *SXDataSection = nullptr;
    221   MCSection *GEHContSection = nullptr;
    222   MCSection *GFIDsSection = nullptr;
    223   MCSection *GIATsSection = nullptr;
    224   MCSection *GLJMPSection = nullptr;
    225 
    226   // XCOFF specific sections
    227   MCSection *TOCBaseSection = nullptr;
    228 
    229 public:
    230   void initMCObjectFileInfo(MCContext &MCCtx, bool PIC,
    231                             bool LargeCodeModel = false);
    232   MCContext &getContext() const { return *Ctx; }
    233 
    234   bool getSupportsWeakOmittedEHFrame() const {
    235     return SupportsWeakOmittedEHFrame;
    236   }
    237   bool getSupportsCompactUnwindWithoutEHFrame() const {
    238     return SupportsCompactUnwindWithoutEHFrame;
    239   }
    240   bool getOmitDwarfIfHaveCompactUnwind() const {
    241     return OmitDwarfIfHaveCompactUnwind;
    242   }
    243 
    244   bool getCommDirectiveSupportsAlignment() const {
    245     return CommDirectiveSupportsAlignment;
    246   }
    247 
    248   unsigned getFDEEncoding() const { return FDECFIEncoding; }
    249 
    250   unsigned getCompactUnwindDwarfEHFrameOnly() const {
    251     return CompactUnwindDwarfEHFrameOnly;
    252   }
    253 
    254   MCSection *getTextSection() const { return TextSection; }
    255   MCSection *getDataSection() const { return DataSection; }
    256   MCSection *getBSSSection() const { return BSSSection; }
    257   MCSection *getReadOnlySection() const { return ReadOnlySection; }
    258   MCSection *getCompactUnwindSection() const { return CompactUnwindSection; }
    259   MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
    260   MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
    261   MCSection *getDwarfInfoSection(uint64_t Hash) const {
    262     return getDwarfComdatSection(".debug_info", Hash);
    263   }
    264   MCSection *getDwarfLineSection() const { return DwarfLineSection; }
    265   MCSection *getDwarfLineStrSection() const { return DwarfLineStrSection; }
    266   MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
    267   MCSection *getDwarfPubNamesSection() const { return DwarfPubNamesSection; }
    268   MCSection *getDwarfPubTypesSection() const { return DwarfPubTypesSection; }
    269   MCSection *getDwarfGnuPubNamesSection() const {
    270     return DwarfGnuPubNamesSection;
    271   }
    272   MCSection *getDwarfGnuPubTypesSection() const {
    273     return DwarfGnuPubTypesSection;
    274   }
    275   const MCSection *getDwarfDebugInlineSection() const {
    276     return DwarfDebugInlineSection;
    277   }
    278   MCSection *getDwarfStrSection() const { return DwarfStrSection; }
    279   MCSection *getDwarfLocSection() const { return DwarfLocSection; }
    280   MCSection *getDwarfARangesSection() const { return DwarfARangesSection; }
    281   MCSection *getDwarfRangesSection() const { return DwarfRangesSection; }
    282   MCSection *getDwarfRnglistsSection() const { return DwarfRnglistsSection; }
    283   MCSection *getDwarfLoclistsSection() const { return DwarfLoclistsSection; }
    284   MCSection *getDwarfMacinfoSection() const { return DwarfMacinfoSection; }
    285   MCSection *getDwarfMacroSection() const { return DwarfMacroSection; }
    286 
    287   MCSection *getDwarfDebugNamesSection() const {
    288     return DwarfDebugNamesSection;
    289   }
    290   MCSection *getDwarfAccelNamesSection() const {
    291     return DwarfAccelNamesSection;
    292   }
    293   MCSection *getDwarfAccelObjCSection() const { return DwarfAccelObjCSection; }
    294   MCSection *getDwarfAccelNamespaceSection() const {
    295     return DwarfAccelNamespaceSection;
    296   }
    297   MCSection *getDwarfAccelTypesSection() const {
    298     return DwarfAccelTypesSection;
    299   }
    300   MCSection *getDwarfInfoDWOSection() const { return DwarfInfoDWOSection; }
    301   MCSection *getDwarfTypesSection(uint64_t Hash) const {
    302     return getDwarfComdatSection(".debug_types", Hash);
    303   }
    304   MCSection *getDwarfTypesDWOSection() const { return DwarfTypesDWOSection; }
    305   MCSection *getDwarfAbbrevDWOSection() const { return DwarfAbbrevDWOSection; }
    306   MCSection *getDwarfStrDWOSection() const { return DwarfStrDWOSection; }
    307   MCSection *getDwarfLineDWOSection() const { return DwarfLineDWOSection; }
    308   MCSection *getDwarfLocDWOSection() const { return DwarfLocDWOSection; }
    309   MCSection *getDwarfStrOffDWOSection() const { return DwarfStrOffDWOSection; }
    310   MCSection *getDwarfStrOffSection() const { return DwarfStrOffSection; }
    311   MCSection *getDwarfAddrSection() const { return DwarfAddrSection; }
    312   MCSection *getDwarfRnglistsDWOSection() const {
    313     return DwarfRnglistsDWOSection;
    314   }
    315   MCSection *getDwarfLoclistsDWOSection() const {
    316     return DwarfLoclistsDWOSection;
    317   }
    318   MCSection *getDwarfMacroDWOSection() const { return DwarfMacroDWOSection; }
    319   MCSection *getDwarfMacinfoDWOSection() const {
    320     return DwarfMacinfoDWOSection;
    321   }
    322   MCSection *getDwarfCUIndexSection() const { return DwarfCUIndexSection; }
    323   MCSection *getDwarfTUIndexSection() const { return DwarfTUIndexSection; }
    324   MCSection *getDwarfSwiftASTSection() const { return DwarfSwiftASTSection; }
    325 
    326   MCSection *getCOFFDebugSymbolsSection() const {
    327     return COFFDebugSymbolsSection;
    328   }
    329   MCSection *getCOFFDebugTypesSection() const {
    330     return COFFDebugTypesSection;
    331   }
    332   MCSection *getCOFFGlobalTypeHashesSection() const {
    333     return COFFGlobalTypeHashesSection;
    334   }
    335 
    336   MCSection *getTLSExtraDataSection() const { return TLSExtraDataSection; }
    337   const MCSection *getTLSDataSection() const { return TLSDataSection; }
    338   MCSection *getTLSBSSSection() const { return TLSBSSSection; }
    339 
    340   MCSection *getStackMapSection() const { return StackMapSection; }
    341   MCSection *getFaultMapSection() const { return FaultMapSection; }
    342   MCSection *getRemarksSection() const { return RemarksSection; }
    343 
    344   MCSection *getStackSizesSection(const MCSection &TextSec) const;
    345 
    346   MCSection *getBBAddrMapSection(const MCSection &TextSec) const;
    347 
    348   MCSection *getPseudoProbeSection(const MCSection *TextSec) const;
    349 
    350   MCSection *getPseudoProbeDescSection(StringRef FuncName) const;
    351 
    352   // ELF specific sections.
    353   MCSection *getDataRelROSection() const { return DataRelROSection; }
    354   const MCSection *getMergeableConst4Section() const {
    355     return MergeableConst4Section;
    356   }
    357   const MCSection *getMergeableConst8Section() const {
    358     return MergeableConst8Section;
    359   }
    360   const MCSection *getMergeableConst16Section() const {
    361     return MergeableConst16Section;
    362   }
    363   const MCSection *getMergeableConst32Section() const {
    364     return MergeableConst32Section;
    365   }
    366 
    367   // MachO specific sections.
    368   const MCSection *getTLSTLVSection() const { return TLSTLVSection; }
    369   const MCSection *getTLSThreadInitSection() const {
    370     return TLSThreadInitSection;
    371   }
    372   const MCSection *getCStringSection() const { return CStringSection; }
    373   const MCSection *getUStringSection() const { return UStringSection; }
    374   MCSection *getTextCoalSection() const { return TextCoalSection; }
    375   const MCSection *getConstTextCoalSection() const {
    376     return ConstTextCoalSection;
    377   }
    378   const MCSection *getConstDataSection() const { return ConstDataSection; }
    379   const MCSection *getDataCoalSection() const { return DataCoalSection; }
    380   const MCSection *getConstDataCoalSection() const {
    381     return ConstDataCoalSection;
    382   }
    383   const MCSection *getDataCommonSection() const { return DataCommonSection; }
    384   MCSection *getDataBSSSection() const { return DataBSSSection; }
    385   const MCSection *getFourByteConstantSection() const {
    386     return FourByteConstantSection;
    387   }
    388   const MCSection *getEightByteConstantSection() const {
    389     return EightByteConstantSection;
    390   }
    391   const MCSection *getSixteenByteConstantSection() const {
    392     return SixteenByteConstantSection;
    393   }
    394   MCSection *getLazySymbolPointerSection() const {
    395     return LazySymbolPointerSection;
    396   }
    397   MCSection *getNonLazySymbolPointerSection() const {
    398     return NonLazySymbolPointerSection;
    399   }
    400   MCSection *getThreadLocalPointerSection() const {
    401     return ThreadLocalPointerSection;
    402   }
    403 
    404   // COFF specific sections.
    405   MCSection *getDrectveSection() const { return DrectveSection; }
    406   MCSection *getPDataSection() const { return PDataSection; }
    407   MCSection *getXDataSection() const { return XDataSection; }
    408   MCSection *getSXDataSection() const { return SXDataSection; }
    409   MCSection *getGEHContSection() const { return GEHContSection; }
    410   MCSection *getGFIDsSection() const { return GFIDsSection; }
    411   MCSection *getGIATsSection() const { return GIATsSection; }
    412   MCSection *getGLJMPSection() const { return GLJMPSection; }
    413 
    414   // XCOFF specific sections
    415   MCSection *getTOCBaseSection() const { return TOCBaseSection; }
    416 
    417   MCSection *getEHFrameSection() const { return EHFrameSection; }
    418 
    419   bool isPositionIndependent() const { return PositionIndependent; }
    420 
    421 private:
    422   bool PositionIndependent = false;
    423   MCContext *Ctx = nullptr;
    424   VersionTuple SDKVersion;
    425 
    426   void initMachOMCObjectFileInfo(const Triple &T);
    427   void initELFMCObjectFileInfo(const Triple &T, bool Large);
    428   void initCOFFMCObjectFileInfo(const Triple &T);
    429   void initWasmMCObjectFileInfo(const Triple &T);
    430   void initXCOFFMCObjectFileInfo(const Triple &T);
    431   MCSection *getDwarfComdatSection(const char *Name, uint64_t Hash) const;
    432 
    433 public:
    434   void setSDKVersion(const VersionTuple &TheSDKVersion) {
    435     SDKVersion = TheSDKVersion;
    436   }
    437 
    438   const VersionTuple &getSDKVersion() const { return SDKVersion; }
    439 };
    440 
    441 } // end namespace llvm
    442 
    443 #endif
    444