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<PATypeHolder> 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   /// LLVM2_7MetadataDetected - True if metadata produced by LLVM 2.7 or
 178   /// earlier was detected, in which case we behave slightly differently,
 179   /// for compatibility.
 180   /// FIXME: Remove in LLVM 3.0.
 181   bool LLVM2_7MetadataDetected;
 182
 183 public:
 184   explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
 185     : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
 186       ErrorString(0), ValueList(C), MDValueList(C),
 187       LLVM2_7MetadataDetected(false) {
 188     HasReversedFunctionsWithBodies = false;
 189   }
 190   ~BitcodeReader() {
 191     FreeState();
 192   }
 193
 194   void FreeState();
 195
 196   /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
 197   /// when the reader is destroyed.
 198   void setBufferOwned(bool Owned) { BufferOwned = Owned; }
 199
 200   virtual bool isMaterializable(const GlobalValue *GV) const;
 201   virtual bool isDematerializable(const GlobalValue *GV) const;
 202   virtual bool Materialize(GlobalValue *GV, std::string *ErrInfo = 0);
 203   virtual bool MaterializeModule(Module *M, std::string *ErrInfo = 0);
 204   virtual void Dematerialize(GlobalValue *GV);
 205
 206   bool Error(const char *Str) {
 207     ErrorString = Str;
 208     return true;
 209   }
 210   const char *getErrorString() const { return ErrorString; }
 211
 212   /// @brief Main interface to parsing a bitcode buffer.
 213   /// @returns true if an error occurred.
 214   bool ParseBitcodeInto(Module *M);
 215
 216   /// @brief Cheap mechanism to just extract module triple
 217   /// @returns true if an error occurred.
 218   bool ParseTriple(std::string &Triple);
 219 private:
 220   const Type *getTypeByID(unsigned ID, bool isTypeTable = false);
 221   Value *getFnValueByID(unsigned ID, const Type *Ty) {
 222     if (Ty == Type::getMetadataTy(Context))
 223       return MDValueList.getValueFwdRef(ID);
 224     else
 225       return ValueList.getValueFwdRef(ID, Ty);
 226   }
 227   BasicBlock *getBasicBlock(unsigned ID) const {
 228     if (ID >= FunctionBBs.size()) return 0; // Invalid ID
 229     return FunctionBBs[ID];
 230   }
 231   AttrListPtr getAttributes(unsigned i) const {
 232     if (i-1 < MAttributes.size())
 233       return MAttributes[i-1];
 234     return AttrListPtr();
 235   }
 236
 237   /// getValueTypePair - Read a value/type pair out of the specified record from
 238   /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
 239   /// Return true on failure.
 240   bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
 241                         unsigned InstNum, Value *&ResVal) {
 242     if (Slot == Record.size()) return true;
 243     unsigned ValNo = (unsigned)Record[Slot++];
 244     if (ValNo < InstNum) {
 245       // If this is not a forward reference, just return the value we already
 246       // have.
 247       ResVal = getFnValueByID(ValNo, 0);
 248       return ResVal == 0;
 249     } else if (Slot == Record.size()) {
 250       return true;
 251     }
 252
 253     unsigned TypeNo = (unsigned)Record[Slot++];
 254     ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
 255     return ResVal == 0;
 256   }
 257   bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
 258                 const Type *Ty, Value *&ResVal) {
 259     if (Slot == Record.size()) return true;
 260     unsigned ValNo = (unsigned)Record[Slot++];
 261     ResVal = getFnValueByID(ValNo, Ty);
 262     return ResVal == 0;
 263   }
 264
 265
 266   bool ParseModule();
 267   bool ParseAttributeBlock();
 268   bool ParseTypeTable();
 269   bool ParseTypeSymbolTable();
 270   bool ParseValueSymbolTable();
 271   bool ParseConstants();
 272   bool RememberAndSkipFunctionBody();
 273   bool ParseFunctionBody(Function *F);
 274   bool ResolveGlobalAndAliasInits();
 275   bool ParseMetadata();
 276   bool ParseMetadataAttachment();
 277   bool ParseModuleTriple(std::string &Triple);
 278 };
 279
 280 } // End llvm namespace
 281
 282 #endif