lib/Bitcode/Reader/BitcodeReader.h

   1 //===- BitcodeReader.h - Internal BitcodeReader impl ------------*- 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 header defines the BitcodeReader class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef BITCODE_READER_H
  15 #define BITCODE_READER_H
  16
  17 #include "llvm/GVMaterializer.h"
  18 #include "llvm/Attributes.h"
  19 #include "llvm/Type.h"
  20 #include "llvm/OperandTraits.h"
  21 #include "llvm/Bitcode/BitstreamReader.h"
  22 #include "llvm/Bitcode/LLVMBitCodes.h"
  23 #include "llvm/Support/ValueHandle.h"
  24 #include "llvm/ADT/DenseMap.h"
  25 #include <vector>
  26
  27 namespace llvm {
  28   class MemoryBuffer;
  29   class LLVMContext;
  30
  31 //===----------------------------------------------------------------------===//
  32 //                          BitcodeReaderValueList Class
  33 //===----------------------------------------------------------------------===//
  34
  35 class BitcodeReaderValueList {
  36   std::vector<WeakVH> ValuePtrs;
  37
  38   /// ResolveConstants - As we resolve forward-referenced constants, we add
  39   /// information about them to this vector.  This allows us to resolve them in
  40   /// bulk instead of resolving each reference at a time.  See the code in
  41   /// ResolveConstantForwardRefs for more information about this.
  42   ///
  43   /// The key of this vector is the placeholder constant, the value is the slot
  44   /// number that holds the resolved value.
  45   typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
  46   ResolveConstantsTy ResolveConstants;
  47   LLVMContext &Context;
  48 public:
  49   BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
  50   ~BitcodeReaderValueList() {
  51     assert(ResolveConstants.empty() && "Constants not resolved?");
  52   }
  53
  54   // vector compatibility methods
  55   unsigned size() const { return ValuePtrs.size(); }
  56   void resize(unsigned N) { ValuePtrs.resize(N); }
  57   void push_back(Value *V) {
  58     ValuePtrs.push_back(V);
  59   }
  60
  61   void clear() {
  62     assert(ResolveConstants.empty() && "Constants not resolved?");
  63     ValuePtrs.clear();
  64   }
  65
  66   Value *operator[](unsigned i) const {
  67     assert(i < ValuePtrs.size());
  68     return ValuePtrs[i];
  69   }
  70
  71   Value *back() const { return ValuePtrs.back(); }
  72     void pop_back() { ValuePtrs.pop_back(); }
  73   bool empty() const { return ValuePtrs.empty(); }
  74   void shrinkTo(unsigned N) {
  75     assert(N <= size() && "Invalid shrinkTo request!");
  76     ValuePtrs.resize(N);
  77   }
  78
  79   Constant *getConstantFwdRef(unsigned Idx, const Type *Ty);
  80   Value *getValueFwdRef(unsigned Idx, const Type *Ty);
  81
  82   void AssignValue(Value *V, unsigned Idx);
  83
  84   /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
  85   /// resolves any forward references.
  86   void ResolveConstantForwardRefs();
  87 };
  88
  89
  90 //===----------------------------------------------------------------------===//
  91 //                          BitcodeReaderMDValueList Class
  92 //===----------------------------------------------------------------------===//
  93
  94 class BitcodeReaderMDValueList {
  95   std::vector<WeakVH> MDValuePtrs;
  96
  97   LLVMContext &Context;
  98 public:
  99   BitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
 100
 101   // vector compatibility methods
 102   unsigned size() const       { return MDValuePtrs.size(); }
 103   void resize(unsigned N)     { MDValuePtrs.resize(N); }
 104   void push_back(Value *V)    { MDValuePtrs.push_back(V);  }
 105   void clear()                { MDValuePtrs.clear();  }
 106   Value *back() const         { return MDValuePtrs.back(); }
 107   void pop_back()             { MDValuePtrs.pop_back(); }
 108   bool empty() const          { return MDValuePtrs.empty(); }
 109
 110   Value *operator[](unsigned i) const {
 111     assert(i < MDValuePtrs.size());
 112     return MDValuePtrs[i];
 113   }
 114
 115   void shrinkTo(unsigned N) {
 116     assert(N <= size() && "Invalid shrinkTo request!");
 117     MDValuePtrs.resize(N);
 118   }
 119
 120   Value *getValueFwdRef(unsigned Idx);
 121   void AssignValue(Value *V, unsigned Idx);
 122 };
 123
 124 class BitcodeReader : public GVMaterializer {
 125   LLVMContext &Context;
 126   Module *TheModule;
 127   MemoryBuffer *Buffer;
 128   bool BufferOwned;
 129   BitstreamReader StreamFile;
 130   BitstreamCursor Stream;
 131
 132   const char *ErrorString;
 133
 134   std::vector<Type*> TypeList;
 135   BitcodeReaderValueList ValueList;
 136   BitcodeReaderMDValueList MDValueList;
 137   SmallVector<Instruction *, 64> InstructionList;
 138
 139   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
 140   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
 141
 142   /// MAttributes - The set of attributes by index.  Index zero in the
 143   /// file is for null, and is thus not represented here.  As such all indices
 144   /// are off by one.
 145   std::vector<AttrListPtr> MAttributes;
 146
 147   /// FunctionBBs - While parsing a function body, this is a list of the basic
 148   /// blocks for the function.
 149   std::vector<BasicBlock*> FunctionBBs;
 150
 151   // When reading the module header, this list is populated with functions that
 152   // have bodies later in the file.
 153   std::vector<Function*> FunctionsWithBodies;
 154
 155   // When intrinsic functions are encountered which require upgrading they are
 156   // stored here with their replacement function.
 157   typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
 158   UpgradedIntrinsicMap UpgradedIntrinsics;
 159
 160   // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
 161   DenseMap<unsigned, unsigned> MDKindMap;
 162
 163   // After the module header has been read, the FunctionsWithBodies list is
 164   // reversed.  This keeps track of whether we've done this yet.
 165   bool HasReversedFunctionsWithBodies;
 166
 167   /// DeferredFunctionInfo - When function bodies are initially scanned, this
 168   /// map contains info about where to find deferred function body in the
 169   /// stream.
 170   DenseMap<Function*, uint64_t> DeferredFunctionInfo;
 171
 172   /// BlockAddrFwdRefs - These are blockaddr references to basic blocks.  These
 173   /// are resolved lazily when functions are loaded.
 174   typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
 175   DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
 176
 177 public:
 178   explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
 179     : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
 180       ErrorString(0), ValueList(C), MDValueList(C) {
 181     HasReversedFunctionsWithBodies = false;
 182   }
 183   ~BitcodeReader() {
 184     FreeState();
 185   }
 186
 187   void FreeState();
 188
 189   /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
 190   /// when the reader is destroyed.
 191   void setBufferOwned(bool Owned) { BufferOwned = Owned; }
 192
 193   virtual bool isMaterializable(const GlobalValue *GV) const;
 194   virtual bool isDematerializable(const GlobalValue *GV) const;
 195   virtual bool Materialize(GlobalValue *GV, std::string *ErrInfo = 0);
 196   virtual bool MaterializeModule(Module *M, std::string *ErrInfo = 0);
 197   virtual void Dematerialize(GlobalValue *GV);
 198
 199   bool Error(const char *Str) {
 200     ErrorString = Str;
 201     return true;
 202   }
 203   const char *getErrorString() const { return ErrorString; }
 204
 205   /// @brief Main interface to parsing a bitcode buffer.
 206   /// @returns true if an error occurred.
 207   bool ParseBitcodeInto(Module *M);
 208
 209   /// @brief Cheap mechanism to just extract module triple
 210   /// @returns true if an error occurred.
 211   bool ParseTriple(std::string &Triple);
 212 private:
 213   Type *getTypeByID(unsigned ID);
 214   Type *getTypeByIDOrNull(unsigned ID);
 215   Value *getFnValueByID(unsigned ID, const Type *Ty) {
 216     if (Ty && Ty->isMetadataTy())
 217       return MDValueList.getValueFwdRef(ID);
 218     return ValueList.getValueFwdRef(ID, Ty);
 219   }
 220   BasicBlock *getBasicBlock(unsigned ID) const {
 221     if (ID >= FunctionBBs.size()) return 0; // Invalid ID
 222     return FunctionBBs[ID];
 223   }
 224   AttrListPtr getAttributes(unsigned i) const {
 225     if (i-1 < MAttributes.size())
 226       return MAttributes[i-1];
 227     return AttrListPtr();
 228   }
 229
 230   /// getValueTypePair - Read a value/type pair out of the specified record from
 231   /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
 232   /// Return true on failure.
 233   bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
 234                         unsigned InstNum, Value *&ResVal) {
 235     if (Slot == Record.size()) return true;
 236     unsigned ValNo = (unsigned)Record[Slot++];
 237     if (ValNo < InstNum) {
 238       // If this is not a forward reference, just return the value we already
 239       // have.
 240       ResVal = getFnValueByID(ValNo, 0);
 241       return ResVal == 0;
 242     } else if (Slot == Record.size()) {
 243       return true;
 244     }
 245
 246     unsigned TypeNo = (unsigned)Record[Slot++];
 247     ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
 248     return ResVal == 0;
 249   }
 250   bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
 251                 const Type *Ty, Value *&ResVal) {
 252     if (Slot == Record.size()) return true;
 253     unsigned ValNo = (unsigned)Record[Slot++];
 254     ResVal = getFnValueByID(ValNo, Ty);
 255     return ResVal == 0;
 256   }
 257
 258
 259   bool ParseModule();
 260   bool ParseAttributeBlock();
 261   bool ParseTypeTable();
 262   bool ParseOldTypeTable();         // FIXME: Remove in LLVM 3.1
 263   bool ParseTypeTableBody();
 264
 265   bool ParseOldTypeSymbolTable();   // FIXME: Remove in LLVM 3.1
 266   bool ParseValueSymbolTable();
 267   bool ParseConstants();
 268   bool RememberAndSkipFunctionBody();
 269   bool ParseFunctionBody(Function *F);
 270   bool ResolveGlobalAndAliasInits();
 271   bool ParseMetadata();
 272   bool ParseMetadataAttachment();
 273   bool ParseModuleTriple(std::string &Triple);
 274 };
 275
 276 } // End llvm namespace
 277
 278 #endif