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      1 //===-- llvm/CodeGen/MachineModuleInfo.h ------------------------*- 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 // Collect meta information for a module.  This information should be in a
     11 // neutral form that can be used by different debugging and exception handling
     12 // schemes.
     13 //
     14 // The organization of information is primarily clustered around the source
     15 // compile units.  The main exception is source line correspondence where
     16 // inlining may interleave code from various compile units.
     17 //
     18 // The following information can be retrieved from the MachineModuleInfo.
     19 //
     20 //  -- Source directories - Directories are uniqued based on their canonical
     21 //     string and assigned a sequential numeric ID (base 1.)
     22 //  -- Source files - Files are also uniqued based on their name and directory
     23 //     ID.  A file ID is sequential number (base 1.)
     24 //  -- Source line correspondence - A vector of file ID, line#, column# triples.
     25 //     A DEBUG_LOCATION instruction is generated  by the DAG Legalizer
     26 //     corresponding to each entry in the source line list.  This allows a debug
     27 //     emitter to generate labels referenced by debug information tables.
     28 //
     29 //===----------------------------------------------------------------------===//
     30 
     31 #ifndef LLVM_CODEGEN_MACHINEMODULEINFO_H
     32 #define LLVM_CODEGEN_MACHINEMODULEINFO_H
     33 
     34 #include "llvm/ADT/DenseMap.h"
     35 #include "llvm/ADT/PointerIntPair.h"
     36 #include "llvm/ADT/SmallPtrSet.h"
     37 #include "llvm/ADT/SmallVector.h"
     38 #include "llvm/IR/DebugLoc.h"
     39 #include "llvm/IR/Metadata.h"
     40 #include "llvm/IR/ValueHandle.h"
     41 #include "llvm/MC/MCContext.h"
     42 #include "llvm/MC/MachineLocation.h"
     43 #include "llvm/Pass.h"
     44 #include "llvm/Support/DataTypes.h"
     45 #include "llvm/Support/Dwarf.h"
     46 
     47 namespace llvm {
     48 
     49 //===----------------------------------------------------------------------===//
     50 // Forward declarations.
     51 class Constant;
     52 class GlobalVariable;
     53 class MDNode;
     54 class MMIAddrLabelMap;
     55 class MachineBasicBlock;
     56 class MachineFunction;
     57 class Module;
     58 class PointerType;
     59 class StructType;
     60 
     61 //===----------------------------------------------------------------------===//
     62 /// LandingPadInfo - This structure is used to retain landing pad info for
     63 /// the current function.
     64 ///
     65 struct LandingPadInfo {
     66   MachineBasicBlock *LandingPadBlock;    // Landing pad block.
     67   SmallVector<MCSymbol*, 1> BeginLabels; // Labels prior to invoke.
     68   SmallVector<MCSymbol*, 1> EndLabels;   // Labels after invoke.
     69   MCSymbol *LandingPadLabel;             // Label at beginning of landing pad.
     70   const Function *Personality;           // Personality function.
     71   std::vector<int> TypeIds;              // List of type ids (filters negative)
     72 
     73   explicit LandingPadInfo(MachineBasicBlock *MBB)
     74     : LandingPadBlock(MBB), LandingPadLabel(nullptr), Personality(nullptr) {}
     75 };
     76 
     77 //===----------------------------------------------------------------------===//
     78 /// MachineModuleInfoImpl - This class can be derived from and used by targets
     79 /// to hold private target-specific information for each Module.  Objects of
     80 /// type are accessed/created with MMI::getInfo and destroyed when the
     81 /// MachineModuleInfo is destroyed.
     82 ///
     83 class MachineModuleInfoImpl {
     84 public:
     85   typedef PointerIntPair<MCSymbol*, 1, bool> StubValueTy;
     86   virtual ~MachineModuleInfoImpl();
     87   typedef std::vector<std::pair<MCSymbol*, StubValueTy> > SymbolListTy;
     88 protected:
     89   static SymbolListTy GetSortedStubs(const DenseMap<MCSymbol*, StubValueTy>&);
     90 };
     91 
     92 //===----------------------------------------------------------------------===//
     93 /// MachineModuleInfo - This class contains meta information specific to a
     94 /// module.  Queries can be made by different debugging and exception handling
     95 /// schemes and reformated for specific use.
     96 ///
     97 class MachineModuleInfo : public ImmutablePass {
     98   /// Context - This is the MCContext used for the entire code generator.
     99   MCContext Context;
    100 
    101   /// TheModule - This is the LLVM Module being worked on.
    102   const Module *TheModule;
    103 
    104   /// ObjFileMMI - This is the object-file-format-specific implementation of
    105   /// MachineModuleInfoImpl, which lets targets accumulate whatever info they
    106   /// want.
    107   MachineModuleInfoImpl *ObjFileMMI;
    108 
    109   /// List of moves done by a function's prolog.  Used to construct frame maps
    110   /// by debug and exception handling consumers.
    111   std::vector<MCCFIInstruction> FrameInstructions;
    112 
    113   /// CompactUnwindEncoding - If the target supports it, this is the compact
    114   /// unwind encoding. It replaces a function's CIE and FDE.
    115   uint32_t CompactUnwindEncoding;
    116 
    117   /// LandingPads - List of LandingPadInfo describing the landing pad
    118   /// information in the current function.
    119   std::vector<LandingPadInfo> LandingPads;
    120 
    121   /// LPadToCallSiteMap - Map a landing pad's EH symbol to the call site
    122   /// indexes.
    123   DenseMap<MCSymbol*, SmallVector<unsigned, 4> > LPadToCallSiteMap;
    124 
    125   /// CallSiteMap - Map of invoke call site index values to associated begin
    126   /// EH_LABEL for the current function.
    127   DenseMap<MCSymbol*, unsigned> CallSiteMap;
    128 
    129   /// CurCallSite - The current call site index being processed, if any. 0 if
    130   /// none.
    131   unsigned CurCallSite;
    132 
    133   /// TypeInfos - List of C++ TypeInfo used in the current function.
    134   std::vector<const GlobalVariable *> TypeInfos;
    135 
    136   /// FilterIds - List of typeids encoding filters used in the current function.
    137   std::vector<unsigned> FilterIds;
    138 
    139   /// FilterEnds - List of the indices in FilterIds corresponding to filter
    140   /// terminators.
    141   std::vector<unsigned> FilterEnds;
    142 
    143   /// Personalities - Vector of all personality functions ever seen. Used to
    144   /// emit common EH frames.
    145   std::vector<const Function *> Personalities;
    146 
    147   /// UsedFunctions - The functions in the @llvm.used list in a more easily
    148   /// searchable format.  This does not include the functions in
    149   /// llvm.compiler.used.
    150   SmallPtrSet<const Function *, 32> UsedFunctions;
    151 
    152   /// AddrLabelSymbols - This map keeps track of which symbol is being used for
    153   /// the specified basic block's address of label.
    154   MMIAddrLabelMap *AddrLabelSymbols;
    155 
    156   bool CallsEHReturn;
    157   bool CallsUnwindInit;
    158 
    159   /// DbgInfoAvailable - True if debugging information is available
    160   /// in this module.
    161   bool DbgInfoAvailable;
    162 
    163   /// UsesVAFloatArgument - True if this module calls VarArg function with
    164   /// floating-point arguments.  This is used to emit an undefined reference
    165   /// to _fltused on Windows targets.
    166   bool UsesVAFloatArgument;
    167 
    168 public:
    169   static char ID; // Pass identification, replacement for typeid
    170 
    171   struct VariableDbgInfo {
    172     TrackingVH<MDNode> Var;
    173     unsigned Slot;
    174     DebugLoc Loc;
    175   };
    176   typedef SmallVector<VariableDbgInfo, 4> VariableDbgInfoMapTy;
    177   VariableDbgInfoMapTy VariableDbgInfos;
    178 
    179   MachineModuleInfo();  // DUMMY CONSTRUCTOR, DO NOT CALL.
    180   // Real constructor.
    181   MachineModuleInfo(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
    182                     const MCObjectFileInfo *MOFI);
    183   ~MachineModuleInfo();
    184 
    185   // Initialization and Finalization
    186   bool doInitialization(Module &) override;
    187   bool doFinalization(Module &) override;
    188 
    189   /// EndFunction - Discard function meta information.
    190   ///
    191   void EndFunction();
    192 
    193   const MCContext &getContext() const { return Context; }
    194   MCContext &getContext() { return Context; }
    195 
    196   void setModule(const Module *M) { TheModule = M; }
    197   const Module *getModule() const { return TheModule; }
    198 
    199   /// getInfo - Keep track of various per-function pieces of information for
    200   /// backends that would like to do so.
    201   ///
    202   template<typename Ty>
    203   Ty &getObjFileInfo() {
    204     if (ObjFileMMI == nullptr)
    205       ObjFileMMI = new Ty(*this);
    206     return *static_cast<Ty*>(ObjFileMMI);
    207   }
    208 
    209   template<typename Ty>
    210   const Ty &getObjFileInfo() const {
    211     return const_cast<MachineModuleInfo*>(this)->getObjFileInfo<Ty>();
    212   }
    213 
    214   /// AnalyzeModule - Scan the module for global debug information.
    215   ///
    216   void AnalyzeModule(const Module &M);
    217 
    218   /// hasDebugInfo - Returns true if valid debug info is present.
    219   ///
    220   bool hasDebugInfo() const { return DbgInfoAvailable; }
    221   void setDebugInfoAvailability(bool avail) { DbgInfoAvailable = avail; }
    222 
    223   bool callsEHReturn() const { return CallsEHReturn; }
    224   void setCallsEHReturn(bool b) { CallsEHReturn = b; }
    225 
    226   bool callsUnwindInit() const { return CallsUnwindInit; }
    227   void setCallsUnwindInit(bool b) { CallsUnwindInit = b; }
    228 
    229   bool usesVAFloatArgument() const {
    230     return UsesVAFloatArgument;
    231   }
    232 
    233   void setUsesVAFloatArgument(bool b) {
    234     UsesVAFloatArgument = b;
    235   }
    236 
    237   /// \brief Returns a reference to a list of cfi instructions in the current
    238   /// function's prologue.  Used to construct frame maps for debug and exception
    239   /// handling comsumers.
    240   const std::vector<MCCFIInstruction> &getFrameInstructions() const {
    241     return FrameInstructions;
    242   }
    243 
    244   unsigned LLVM_ATTRIBUTE_UNUSED_RESULT
    245   addFrameInst(const MCCFIInstruction &Inst) {
    246     FrameInstructions.push_back(Inst);
    247     return FrameInstructions.size() - 1;
    248   }
    249 
    250   /// getCompactUnwindEncoding - Returns the compact unwind encoding for a
    251   /// function if the target supports the encoding. This encoding replaces a
    252   /// function's CIE and FDE.
    253   uint32_t getCompactUnwindEncoding() const { return CompactUnwindEncoding; }
    254 
    255   /// setCompactUnwindEncoding - Set the compact unwind encoding for a function
    256   /// if the target supports the encoding.
    257   void setCompactUnwindEncoding(uint32_t Enc) { CompactUnwindEncoding = Enc; }
    258 
    259   /// getAddrLabelSymbol - Return the symbol to be used for the specified basic
    260   /// block when its address is taken.  This cannot be its normal LBB label
    261   /// because the block may be accessed outside its containing function.
    262   MCSymbol *getAddrLabelSymbol(const BasicBlock *BB);
    263 
    264   /// getAddrLabelSymbolToEmit - Return the symbol to be used for the specified
    265   /// basic block when its address is taken.  If other blocks were RAUW'd to
    266   /// this one, we may have to emit them as well, return the whole set.
    267   std::vector<MCSymbol*> getAddrLabelSymbolToEmit(const BasicBlock *BB);
    268 
    269   /// takeDeletedSymbolsForFunction - If the specified function has had any
    270   /// references to address-taken blocks generated, but the block got deleted,
    271   /// return the symbol now so we can emit it.  This prevents emitting a
    272   /// reference to a symbol that has no definition.
    273   void takeDeletedSymbolsForFunction(const Function *F,
    274                                      std::vector<MCSymbol*> &Result);
    275 
    276 
    277   //===- EH ---------------------------------------------------------------===//
    278 
    279   /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
    280   /// specified MachineBasicBlock.
    281   LandingPadInfo &getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad);
    282 
    283   /// addInvoke - Provide the begin and end labels of an invoke style call and
    284   /// associate it with a try landing pad block.
    285   void addInvoke(MachineBasicBlock *LandingPad,
    286                  MCSymbol *BeginLabel, MCSymbol *EndLabel);
    287 
    288   /// addLandingPad - Add a new panding pad.  Returns the label ID for the
    289   /// landing pad entry.
    290   MCSymbol *addLandingPad(MachineBasicBlock *LandingPad);
    291 
    292   /// addPersonality - Provide the personality function for the exception
    293   /// information.
    294   void addPersonality(MachineBasicBlock *LandingPad,
    295                       const Function *Personality);
    296 
    297   /// getPersonalityIndex - Get index of the current personality function inside
    298   /// Personalitites array
    299   unsigned getPersonalityIndex() const;
    300 
    301   /// getPersonalities - Return array of personality functions ever seen.
    302   const std::vector<const Function *>& getPersonalities() const {
    303     return Personalities;
    304   }
    305 
    306   /// isUsedFunction - Return true if the functions in the llvm.used list.  This
    307   /// does not return true for things in llvm.compiler.used unless they are also
    308   /// in llvm.used.
    309   bool isUsedFunction(const Function *F) const {
    310     return UsedFunctions.count(F);
    311   }
    312 
    313   /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
    314   ///
    315   void addCatchTypeInfo(MachineBasicBlock *LandingPad,
    316                         ArrayRef<const GlobalVariable *> TyInfo);
    317 
    318   /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
    319   ///
    320   void addFilterTypeInfo(MachineBasicBlock *LandingPad,
    321                          ArrayRef<const GlobalVariable *> TyInfo);
    322 
    323   /// addCleanup - Add a cleanup action for a landing pad.
    324   ///
    325   void addCleanup(MachineBasicBlock *LandingPad);
    326 
    327   /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
    328   /// function wide.
    329   unsigned getTypeIDFor(const GlobalVariable *TI);
    330 
    331   /// getFilterIDFor - Return the id of the filter encoded by TyIds.  This is
    332   /// function wide.
    333   int getFilterIDFor(std::vector<unsigned> &TyIds);
    334 
    335   /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
    336   /// pads.
    337   void TidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap = nullptr);
    338 
    339   /// getLandingPads - Return a reference to the landing pad info for the
    340   /// current function.
    341   const std::vector<LandingPadInfo> &getLandingPads() const {
    342     return LandingPads;
    343   }
    344 
    345   /// setCallSiteLandingPad - Map the landing pad's EH symbol to the call
    346   /// site indexes.
    347   void setCallSiteLandingPad(MCSymbol *Sym, ArrayRef<unsigned> Sites);
    348 
    349   /// getCallSiteLandingPad - Get the call site indexes for a landing pad EH
    350   /// symbol.
    351   SmallVectorImpl<unsigned> &getCallSiteLandingPad(MCSymbol *Sym) {
    352     assert(hasCallSiteLandingPad(Sym) &&
    353            "missing call site number for landing pad!");
    354     return LPadToCallSiteMap[Sym];
    355   }
    356 
    357   /// hasCallSiteLandingPad - Return true if the landing pad Eh symbol has an
    358   /// associated call site.
    359   bool hasCallSiteLandingPad(MCSymbol *Sym) {
    360     return !LPadToCallSiteMap[Sym].empty();
    361   }
    362 
    363   /// setCallSiteBeginLabel - Map the begin label for a call site.
    364   void setCallSiteBeginLabel(MCSymbol *BeginLabel, unsigned Site) {
    365     CallSiteMap[BeginLabel] = Site;
    366   }
    367 
    368   /// getCallSiteBeginLabel - Get the call site number for a begin label.
    369   unsigned getCallSiteBeginLabel(MCSymbol *BeginLabel) {
    370     assert(hasCallSiteBeginLabel(BeginLabel) &&
    371            "Missing call site number for EH_LABEL!");
    372     return CallSiteMap[BeginLabel];
    373   }
    374 
    375   /// hasCallSiteBeginLabel - Return true if the begin label has a call site
    376   /// number associated with it.
    377   bool hasCallSiteBeginLabel(MCSymbol *BeginLabel) {
    378     return CallSiteMap[BeginLabel] != 0;
    379   }
    380 
    381   /// setCurrentCallSite - Set the call site currently being processed.
    382   void setCurrentCallSite(unsigned Site) { CurCallSite = Site; }
    383 
    384   /// getCurrentCallSite - Get the call site currently being processed, if any.
    385   /// return zero if none.
    386   unsigned getCurrentCallSite() { return CurCallSite; }
    387 
    388   /// getTypeInfos - Return a reference to the C++ typeinfo for the current
    389   /// function.
    390   const std::vector<const GlobalVariable *> &getTypeInfos() const {
    391     return TypeInfos;
    392   }
    393 
    394   /// getFilterIds - Return a reference to the typeids encoding filters used in
    395   /// the current function.
    396   const std::vector<unsigned> &getFilterIds() const {
    397     return FilterIds;
    398   }
    399 
    400   /// getPersonality - Return a personality function if available.  The presence
    401   /// of one is required to emit exception handling info.
    402   const Function *getPersonality() const;
    403 
    404   /// setVariableDbgInfo - Collect information used to emit debugging
    405   /// information of a variable.
    406   void setVariableDbgInfo(MDNode *N, unsigned Slot, DebugLoc Loc) {
    407     VariableDbgInfo Info = { N, Slot, Loc };
    408     VariableDbgInfos.push_back(std::move(Info));
    409   }
    410 
    411   VariableDbgInfoMapTy &getVariableDbgInfo() { return VariableDbgInfos; }
    412 
    413 }; // End class MachineModuleInfo
    414 
    415 } // End llvm namespace
    416 
    417 #endif
    418