LCOV - code coverage report
Current view: top level - include/llvm/MC - MCAssembler.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 31 31 100.0 %
Date: 2018-07-13 00:08:38 Functions: 2 2 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- MCAssembler.h - Object File Generation -------------------*- 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             : #ifndef LLVM_MC_MCASSEMBLER_H
      11             : #define LLVM_MC_MCASSEMBLER_H
      12             : 
      13             : #include "llvm/ADT/ArrayRef.h"
      14             : #include "llvm/ADT/STLExtras.h"
      15             : #include "llvm/ADT/SmallPtrSet.h"
      16             : #include "llvm/ADT/StringRef.h"
      17             : #include "llvm/ADT/iterator.h"
      18             : #include "llvm/ADT/iterator_range.h"
      19             : #include "llvm/BinaryFormat/MachO.h"
      20             : #include "llvm/MC/MCDirectives.h"
      21             : #include "llvm/MC/MCDwarf.h"
      22             : #include "llvm/MC/MCFixup.h"
      23             : #include "llvm/MC/MCFragment.h"
      24             : #include "llvm/MC/MCLinkerOptimizationHint.h"
      25             : #include "llvm/MC/MCSymbol.h"
      26             : #include <cassert>
      27             : #include <cstddef>
      28             : #include <cstdint>
      29             : #include <string>
      30             : #include <utility>
      31             : #include <vector>
      32             : 
      33             : namespace llvm {
      34             : 
      35             : class MCAsmBackend;
      36             : class MCAsmLayout;
      37             : class MCContext;
      38             : class MCCodeEmitter;
      39             : class MCFragment;
      40             : class MCObjectWriter;
      41             : class MCSection;
      42             : class MCValue;
      43             : 
      44             : // FIXME: This really doesn't belong here. See comments below.
      45             : struct IndirectSymbolData {
      46             :   MCSymbol *Symbol;
      47             :   MCSection *Section;
      48             : };
      49             : 
      50             : // FIXME: Ditto this. Purely so the Streamer and the ObjectWriter can talk
      51             : // to one another.
      52             : struct DataRegionData {
      53             :   // This enum should be kept in sync w/ the mach-o definition in
      54             :   // llvm/Object/MachOFormat.h.
      55             :   enum KindTy { Data = 1, JumpTable8, JumpTable16, JumpTable32 } Kind;
      56             :   MCSymbol *Start;
      57             :   MCSymbol *End;
      58             : };
      59             : 
      60       87855 : class MCAssembler {
      61             :   friend class MCAsmLayout;
      62             : 
      63             : public:
      64             :   using SectionListType = std::vector<MCSection *>;
      65             :   using SymbolDataListType = std::vector<const MCSymbol *>;
      66             : 
      67             :   using const_iterator = pointee_iterator<SectionListType::const_iterator>;
      68             :   using iterator = pointee_iterator<SectionListType::iterator>;
      69             : 
      70             :   using const_symbol_iterator =
      71             :       pointee_iterator<SymbolDataListType::const_iterator>;
      72             :   using symbol_iterator = pointee_iterator<SymbolDataListType::iterator>;
      73             : 
      74             :   using symbol_range = iterator_range<symbol_iterator>;
      75             :   using const_symbol_range = iterator_range<const_symbol_iterator>;
      76             : 
      77             :   using const_indirect_symbol_iterator =
      78             :       std::vector<IndirectSymbolData>::const_iterator;
      79             :   using indirect_symbol_iterator = std::vector<IndirectSymbolData>::iterator;
      80             : 
      81             :   using const_data_region_iterator =
      82             :       std::vector<DataRegionData>::const_iterator;
      83             :   using data_region_iterator = std::vector<DataRegionData>::iterator;
      84             : 
      85             :   /// MachO specific deployment target version info.
      86             :   // A Major version of 0 indicates that no version information was supplied
      87             :   // and so the corresponding load command should not be emitted.
      88             :   using VersionInfoType = struct {
      89             :     bool EmitBuildVersion;
      90             :     union {
      91             :       MCVersionMinType Type;          ///< Used when EmitBuildVersion==false.
      92             :       MachO::PlatformType Platform;   ///< Used when EmitBuildVersion==true.
      93             :     } TypeOrPlatform;
      94             :     unsigned Major;
      95             :     unsigned Minor;
      96             :     unsigned Update;
      97             :   };
      98             : 
      99             : private:
     100             :   MCContext &Context;
     101             : 
     102             :   std::unique_ptr<MCAsmBackend> Backend;
     103             : 
     104             :   std::unique_ptr<MCCodeEmitter> Emitter;
     105             : 
     106             :   std::unique_ptr<MCObjectWriter> Writer;
     107             : 
     108             :   SectionListType Sections;
     109             : 
     110             :   SymbolDataListType Symbols;
     111             : 
     112             :   std::vector<IndirectSymbolData> IndirectSymbols;
     113             : 
     114             :   std::vector<DataRegionData> DataRegions;
     115             : 
     116             :   /// The list of linker options to propagate into the object file.
     117             :   std::vector<std::vector<std::string>> LinkerOptions;
     118             : 
     119             :   /// List of declared file names
     120             :   std::vector<std::string> FileNames;
     121             : 
     122             :   MCDwarfLineTableParams LTParams;
     123             : 
     124             :   /// The set of function symbols for which a .thumb_func directive has
     125             :   /// been seen.
     126             :   //
     127             :   // FIXME: We really would like this in target specific code rather than
     128             :   // here. Maybe when the relocation stuff moves to target specific,
     129             :   // this can go with it? The streamer would need some target specific
     130             :   // refactoring too.
     131             :   mutable SmallPtrSet<const MCSymbol *, 32> ThumbFuncs;
     132             : 
     133             :   /// The bundle alignment size currently set in the assembler.
     134             :   ///
     135             :   /// By default it's 0, which means bundling is disabled.
     136             :   unsigned BundleAlignSize;
     137             : 
     138             :   bool RelaxAll : 1;
     139             :   bool SubsectionsViaSymbols : 1;
     140             :   bool IncrementalLinkerCompatible : 1;
     141             : 
     142             :   /// ELF specific e_header flags
     143             :   // It would be good if there were an MCELFAssembler class to hold this.
     144             :   // ELF header flags are used both by the integrated and standalone assemblers.
     145             :   // Access to the flags is necessary in cases where assembler directives affect
     146             :   // which flags to be set.
     147             :   unsigned ELFHeaderEFlags;
     148             : 
     149             :   /// Used to communicate Linker Optimization Hint information between
     150             :   /// the Streamer and the .o writer
     151             :   MCLOHContainer LOHContainer;
     152             : 
     153             :   VersionInfoType VersionInfo;
     154             : 
     155             :   /// Evaluate a fixup to a relocatable expression and the value which should be
     156             :   /// placed into the fixup.
     157             :   ///
     158             :   /// \param Layout The layout to use for evaluation.
     159             :   /// \param Fixup The fixup to evaluate.
     160             :   /// \param DF The fragment the fixup is inside.
     161             :   /// \param Target [out] On return, the relocatable expression the fixup
     162             :   /// evaluates to.
     163             :   /// \param Value [out] On return, the value of the fixup as currently laid
     164             :   /// out.
     165             :   /// \param WasForced [out] On return, the value in the fixup is set to the
     166             :   /// correct value if WasForced is true, even if evaluateFixup returns false.
     167             :   /// \return Whether the fixup value was fully resolved. This is true if the
     168             :   /// \p Value result is fixed, otherwise the value may change due to
     169             :   /// relocation.
     170             :   bool evaluateFixup(const MCAsmLayout &Layout, const MCFixup &Fixup,
     171             :                      const MCFragment *DF, MCValue &Target,
     172             :                      uint64_t &Value, bool &WasForced) const;
     173             : 
     174             :   /// Check whether a fixup can be satisfied, or whether it needs to be relaxed
     175             :   /// (increased in size, in order to hold its value correctly).
     176             :   bool fixupNeedsRelaxation(const MCFixup &Fixup, const MCRelaxableFragment *DF,
     177             :                             const MCAsmLayout &Layout) const;
     178             : 
     179             :   /// Check whether the given fragment needs relaxation.
     180             :   bool fragmentNeedsRelaxation(const MCRelaxableFragment *IF,
     181             :                                const MCAsmLayout &Layout) const;
     182             : 
     183             :   /// Perform one layout iteration and return true if any offsets
     184             :   /// were adjusted.
     185             :   bool layoutOnce(MCAsmLayout &Layout);
     186             : 
     187             :   /// Perform one layout iteration of the given section and return true
     188             :   /// if any offsets were adjusted.
     189             :   bool layoutSectionOnce(MCAsmLayout &Layout, MCSection &Sec);
     190             : 
     191             :   bool relaxInstruction(MCAsmLayout &Layout, MCRelaxableFragment &IF);
     192             : 
     193             :   bool relaxPaddingFragment(MCAsmLayout &Layout, MCPaddingFragment &PF);
     194             : 
     195             :   bool relaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF);
     196             : 
     197             :   bool relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF);
     198             :   bool relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
     199             :                                    MCDwarfCallFrameFragment &DF);
     200             :   bool relaxCVInlineLineTable(MCAsmLayout &Layout,
     201             :                               MCCVInlineLineTableFragment &DF);
     202             :   bool relaxCVDefRange(MCAsmLayout &Layout, MCCVDefRangeFragment &DF);
     203             : 
     204             :   /// finishLayout - Finalize a layout, including fragment lowering.
     205             :   void finishLayout(MCAsmLayout &Layout);
     206             : 
     207             :   std::tuple<MCValue, uint64_t, bool>
     208             :   handleFixup(const MCAsmLayout &Layout, MCFragment &F, const MCFixup &Fixup);
     209             : 
     210             : public:
     211             :   std::vector<std::pair<StringRef, const MCSymbol *>> Symvers;
     212             : 
     213             :   /// Construct a new assembler instance.
     214             :   //
     215             :   // FIXME: How are we going to parameterize this? Two obvious options are stay
     216             :   // concrete and require clients to pass in a target like object. The other
     217             :   // option is to make this abstract, and have targets provide concrete
     218             :   // implementations as we do with AsmParser.
     219             :   MCAssembler(MCContext &Context, std::unique_ptr<MCAsmBackend> Backend,
     220             :               std::unique_ptr<MCCodeEmitter> Emitter,
     221             :               std::unique_ptr<MCObjectWriter> Writer);
     222             :   MCAssembler(const MCAssembler &) = delete;
     223             :   MCAssembler &operator=(const MCAssembler &) = delete;
     224             :   ~MCAssembler();
     225             : 
     226             :   /// Compute the effective fragment size assuming it is laid out at the given
     227             :   /// \p SectionAddress and \p FragmentOffset.
     228             :   uint64_t computeFragmentSize(const MCAsmLayout &Layout,
     229             :                                const MCFragment &F) const;
     230             : 
     231             :   /// Find the symbol which defines the atom containing the given symbol, or
     232             :   /// null if there is no such symbol.
     233             :   const MCSymbol *getAtom(const MCSymbol &S) const;
     234             : 
     235             :   /// Check whether a particular symbol is visible to the linker and is required
     236             :   /// in the symbol table, or whether it can be discarded by the assembler. This
     237             :   /// also effects whether the assembler treats the label as potentially
     238             :   /// defining a separate atom.
     239             :   bool isSymbolLinkerVisible(const MCSymbol &SD) const;
     240             : 
     241             :   /// Emit the section contents to \p OS.
     242             :   void writeSectionData(raw_ostream &OS, const MCSection *Section,
     243             :                         const MCAsmLayout &Layout) const;
     244             : 
     245             :   /// Check whether a given symbol has been flagged with .thumb_func.
     246             :   bool isThumbFunc(const MCSymbol *Func) const;
     247             : 
     248             :   /// Flag a function symbol as the target of a .thumb_func directive.
     249         962 :   void setIsThumbFunc(const MCSymbol *Func) { ThumbFuncs.insert(Func); }
     250             : 
     251             :   /// ELF e_header flags
     252             :   unsigned getELFHeaderEFlags() const { return ELFHeaderEFlags; }
     253        2484 :   void setELFHeaderEFlags(unsigned Flags) { ELFHeaderEFlags = Flags; }
     254             : 
     255             :   /// MachO deployment target version information.
     256             :   const VersionInfoType &getVersionInfo() const { return VersionInfo; }
     257             :   void setVersionMin(MCVersionMinType Type, unsigned Major, unsigned Minor,
     258             :                      unsigned Update) {
     259         345 :     VersionInfo.EmitBuildVersion = false;
     260         345 :     VersionInfo.TypeOrPlatform.Type = Type;
     261         345 :     VersionInfo.Major = Major;
     262         345 :     VersionInfo.Minor = Minor;
     263         345 :     VersionInfo.Update = Update;
     264             :   }
     265             :   void setBuildVersion(MachO::PlatformType Platform, unsigned Major,
     266             :                        unsigned Minor, unsigned Update) {
     267           1 :     VersionInfo.EmitBuildVersion = true;
     268           1 :     VersionInfo.TypeOrPlatform.Platform = Platform;
     269           1 :     VersionInfo.Major = Major;
     270           1 :     VersionInfo.Minor = Minor;
     271           1 :     VersionInfo.Update = Update;
     272             :   }
     273             : 
     274             :   /// Reuse an assembler instance
     275             :   ///
     276             :   void reset();
     277             : 
     278             :   MCContext &getContext() const { return Context; }
     279             : 
     280             :   MCAsmBackend *getBackendPtr() const { return Backend.get(); }
     281             : 
     282             :   MCCodeEmitter *getEmitterPtr() const { return Emitter.get(); }
     283             : 
     284             :   MCObjectWriter *getWriterPtr() const { return Writer.get(); }
     285             : 
     286             :   MCAsmBackend &getBackend() const { return *Backend; }
     287             : 
     288             :   MCCodeEmitter &getEmitter() const { return *Emitter; }
     289             : 
     290             :   MCObjectWriter &getWriter() const { return *Writer; }
     291             : 
     292     2250330 :   MCDwarfLineTableParams getDWARFLinetableParams() const { return LTParams; }
     293             :   void setDWARFLinetableParams(MCDwarfLineTableParams P) { LTParams = P; }
     294             : 
     295             :   /// Finish - Do final processing and write the object to the output stream.
     296             :   /// \p Writer is used for custom object writer (as the MCJIT does),
     297             :   /// if not specified it is automatically created from backend.
     298             :   void Finish();
     299             : 
     300             :   // Layout all section and prepare them for emission.
     301             :   void layout(MCAsmLayout &Layout);
     302             : 
     303             :   // FIXME: This does not belong here.
     304         653 :   bool getSubsectionsViaSymbols() const { return SubsectionsViaSymbols; }
     305         366 :   void setSubsectionsViaSymbols(bool Value) { SubsectionsViaSymbols = Value; }
     306             : 
     307             :   bool isIncrementalLinkerCompatible() const {
     308         378 :     return IncrementalLinkerCompatible;
     309             :   }
     310             :   void setIncrementalLinkerCompatible(bool Value) {
     311         386 :     IncrementalLinkerCompatible = Value;
     312             :   }
     313             : 
     314      174410 :   bool getRelaxAll() const { return RelaxAll; }
     315        1892 :   void setRelaxAll(bool Value) { RelaxAll = Value; }
     316             : 
     317             :   bool isBundlingEnabled() const { return BundleAlignSize != 0; }
     318             : 
     319             :   unsigned getBundleAlignSize() const { return BundleAlignSize; }
     320             : 
     321             :   void setBundleAlignSize(unsigned Size) {
     322             :     assert((Size == 0 || !(Size & (Size - 1))) &&
     323             :            "Expect a power-of-two bundle align size");
     324          42 :     BundleAlignSize = Size;
     325             :   }
     326             : 
     327             :   /// \name Section List Access
     328             :   /// @{
     329             : 
     330             :   iterator begin() { return Sections.begin(); }
     331             :   const_iterator begin() const { return Sections.begin(); }
     332             : 
     333             :   iterator end() { return Sections.end(); }
     334             :   const_iterator end() const { return Sections.end(); }
     335             : 
     336         600 :   size_t size() const { return Sections.size(); }
     337             : 
     338             :   /// @}
     339             :   /// \name Symbol List Access
     340             :   /// @{
     341             :   symbol_iterator symbol_begin() { return Symbols.begin(); }
     342             :   const_symbol_iterator symbol_begin() const { return Symbols.begin(); }
     343             : 
     344             :   symbol_iterator symbol_end() { return Symbols.end(); }
     345             :   const_symbol_iterator symbol_end() const { return Symbols.end(); }
     346             : 
     347             :   symbol_range symbols() { return make_range(symbol_begin(), symbol_end()); }
     348             :   const_symbol_range symbols() const {
     349             :     return make_range(symbol_begin(), symbol_end());
     350             :   }
     351             : 
     352             :   size_t symbol_size() const { return Symbols.size(); }
     353             : 
     354             :   /// @}
     355             :   /// \name Indirect Symbol List Access
     356             :   /// @{
     357             : 
     358             :   // FIXME: This is a total hack, this should not be here. Once things are
     359             :   // factored so that the streamer has direct access to the .o writer, it can
     360             :   // disappear.
     361             :   std::vector<IndirectSymbolData> &getIndirectSymbols() {
     362          41 :     return IndirectSymbols;
     363             :   }
     364             : 
     365             :   indirect_symbol_iterator indirect_symbol_begin() {
     366             :     return IndirectSymbols.begin();
     367             :   }
     368             :   const_indirect_symbol_iterator indirect_symbol_begin() const {
     369             :     return IndirectSymbols.begin();
     370             :   }
     371             : 
     372             :   indirect_symbol_iterator indirect_symbol_end() {
     373             :     return IndirectSymbols.end();
     374             :   }
     375             :   const_indirect_symbol_iterator indirect_symbol_end() const {
     376             :     return IndirectSymbols.end();
     377             :   }
     378             : 
     379         483 :   size_t indirect_symbol_size() const { return IndirectSymbols.size(); }
     380             : 
     381             :   /// @}
     382             :   /// \name Linker Option List Access
     383             :   /// @{
     384             : 
     385             :   std::vector<std::vector<std::string>> &getLinkerOptions() {
     386           5 :     return LinkerOptions;
     387             :   }
     388             : 
     389             :   /// @}
     390             :   /// \name Data Region List Access
     391             :   /// @{
     392             : 
     393             :   // FIXME: This is a total hack, this should not be here. Once things are
     394             :   // factored so that the streamer has direct access to the .o writer, it can
     395             :   // disappear.
     396          48 :   std::vector<DataRegionData> &getDataRegions() { return DataRegions; }
     397             : 
     398             :   data_region_iterator data_region_begin() { return DataRegions.begin(); }
     399             :   const_data_region_iterator data_region_begin() const {
     400             :     return DataRegions.begin();
     401             :   }
     402             : 
     403             :   data_region_iterator data_region_end() { return DataRegions.end(); }
     404             :   const_data_region_iterator data_region_end() const {
     405             :     return DataRegions.end();
     406             :   }
     407             : 
     408             :   size_t data_region_size() const { return DataRegions.size(); }
     409             : 
     410             :   /// @}
     411             :   /// \name Data Region List Access
     412             :   /// @{
     413             : 
     414             :   // FIXME: This is a total hack, this should not be here. Once things are
     415             :   // factored so that the streamer has direct access to the .o writer, it can
     416             :   // disappear.
     417         601 :   MCLOHContainer &getLOHContainer() { return LOHContainer; }
     418             :   const MCLOHContainer &getLOHContainer() const {
     419             :     return const_cast<MCAssembler *>(this)->getLOHContainer();
     420             :   }
     421             : 
     422             :   struct CGProfileEntry {
     423             :     const MCSymbolRefExpr *From;
     424             :     const MCSymbolRefExpr *To;
     425             :     uint64_t Count;
     426             :   };
     427             :   std::vector<CGProfileEntry> CGProfile;
     428             :   /// @}
     429             :   /// \name Backend Data Access
     430             :   /// @{
     431             : 
     432             :   bool registerSection(MCSection &Section);
     433             : 
     434             :   void registerSymbol(const MCSymbol &Symbol, bool *Created = nullptr);
     435             : 
     436             :   ArrayRef<std::string> getFileNames() { return FileNames; }
     437             : 
     438        3169 :   void addFileName(StringRef FileName) {
     439        3169 :     if (!is_contained(FileNames, FileName))
     440        6338 :       FileNames.push_back(FileName);
     441        3169 :   }
     442             : 
     443             :   /// Write the necessary bundle padding to \p OS.
     444             :   /// Expects a fragment \p F containing instructions and its size \p FSize.
     445             :   void writeFragmentPadding(raw_ostream &OS, const MCEncodedFragment &F,
     446             :                             uint64_t FSize) const;
     447             : 
     448             :   /// @}
     449             : 
     450             :   void dump() const;
     451             : };
     452             : 
     453             : /// Compute the amount of padding required before the fragment \p F to
     454             : /// obey bundling restrictions, where \p FOffset is the fragment's offset in
     455             : /// its section and \p FSize is the fragment's size.
     456             : uint64_t computeBundlePadding(const MCAssembler &Assembler,
     457             :                               const MCEncodedFragment *F, uint64_t FOffset,
     458             :                               uint64_t FSize);
     459             : 
     460             : } // end namespace llvm
     461             : 
     462             : #endif // LLVM_MC_MCASSEMBLER_H

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