Initial import of the Apple clang-425.0.24 branch

lib/Bitcode/Reader/BitcodeReader.h

@@ -0,0 +1,296 @@
+//===- BitcodeReader.h - Internal BitcodeReader impl ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines the BitcodeReader class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BITCODE_READER_H
+#define BITCODE_READER_H
+
+#include "llvm/GVMaterializer.h"
+#include "llvm/Attributes.h"
+#include "llvm/Type.h"
+#include "llvm/OperandTraits.h"
+#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitcode/LLVMBitCodes.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/ADT/DenseMap.h"
+#include <vector>
+
+namespace llvm {
+  class MemoryBuffer;
+  class LLVMContext;
+  
+//===----------------------------------------------------------------------===//
+//                          BitcodeReaderValueList Class
+//===----------------------------------------------------------------------===//
+
+class BitcodeReaderValueList {
+  std::vector<WeakVH> ValuePtrs;
+  
+  /// ResolveConstants - As we resolve forward-referenced constants, we add
+  /// information about them to this vector.  This allows us to resolve them in
+  /// bulk instead of resolving each reference at a time.  See the code in
+  /// ResolveConstantForwardRefs for more information about this.
+  ///
+  /// The key of this vector is the placeholder constant, the value is the slot
+  /// number that holds the resolved value.
+  typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
+  ResolveConstantsTy ResolveConstants;
+  LLVMContext &Context;
+public:
+  BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
+  ~BitcodeReaderValueList() {
+    assert(ResolveConstants.empty() && "Constants not resolved?");
+  }
+
+  // vector compatibility methods
+  unsigned size() const { return ValuePtrs.size(); }
+  void resize(unsigned N) { ValuePtrs.resize(N); }
+  void push_back(Value *V) {
+    ValuePtrs.push_back(V);
+  }
+  
+  void clear() {
+    assert(ResolveConstants.empty() && "Constants not resolved?");
+    ValuePtrs.clear();
+  }
+  
+  Value *operator[](unsigned i) const {
+    assert(i < ValuePtrs.size());
+    return ValuePtrs[i];
+  }
+  
+  Value *back() const { return ValuePtrs.back(); }
+    void pop_back() { ValuePtrs.pop_back(); }
+  bool empty() const { return ValuePtrs.empty(); }
+  void shrinkTo(unsigned N) {
+    assert(N <= size() && "Invalid shrinkTo request!");
+    ValuePtrs.resize(N);
+  }
+  
+  Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
+  Value *getValueFwdRef(unsigned Idx, Type *Ty);
+  
+  void AssignValue(Value *V, unsigned Idx);
+  
+  /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
+  /// resolves any forward references.
+  void ResolveConstantForwardRefs();
+};
+
+
+//===----------------------------------------------------------------------===//
+//                          BitcodeReaderMDValueList Class
+//===----------------------------------------------------------------------===//
+
+class BitcodeReaderMDValueList {
+  std::vector<WeakVH> MDValuePtrs;
+  
+  LLVMContext &Context;
+public:
+  BitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
+
+  // vector compatibility methods
+  unsigned size() const       { return MDValuePtrs.size(); }
+  void resize(unsigned N)     { MDValuePtrs.resize(N); }
+  void push_back(Value *V)    { MDValuePtrs.push_back(V);  }
+  void clear()                { MDValuePtrs.clear();  }
+  Value *back() const         { return MDValuePtrs.back(); }
+  void pop_back()             { MDValuePtrs.pop_back(); }
+  bool empty() const          { return MDValuePtrs.empty(); }
+  
+  Value *operator[](unsigned i) const {
+    assert(i < MDValuePtrs.size());
+    return MDValuePtrs[i];
+  }
+  
+  void shrinkTo(unsigned N) {
+    assert(N <= size() && "Invalid shrinkTo request!");
+    MDValuePtrs.resize(N);
+  }
+
+  Value *getValueFwdRef(unsigned Idx);
+  void AssignValue(Value *V, unsigned Idx);
+};
+
+class BitcodeReader : public GVMaterializer {
+  LLVMContext &Context;
+  Module *TheModule;
+  MemoryBuffer *Buffer;
+  bool BufferOwned;
+  OwningPtr<BitstreamReader> StreamFile;
+  BitstreamCursor Stream;
+  DataStreamer *LazyStreamer;
+  uint64_t NextUnreadBit;
+  bool SeenValueSymbolTable;
+  
+  const char *ErrorString;
+  
+  std::vector<Type*> TypeList;
+  BitcodeReaderValueList ValueList;
+  BitcodeReaderMDValueList MDValueList;
+  SmallVector<Instruction *, 64> InstructionList;
+  SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
+
+  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
+  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
+  
+  /// MAttributes - The set of attributes by index.  Index zero in the
+  /// file is for null, and is thus not represented here.  As such all indices
+  /// are off by one.
+  std::vector<AttrListPtr> MAttributes;
+  
+  /// FunctionBBs - While parsing a function body, this is a list of the basic
+  /// blocks for the function.
+  std::vector<BasicBlock*> FunctionBBs;
+  
+  // When reading the module header, this list is populated with functions that
+  // have bodies later in the file.
+  std::vector<Function*> FunctionsWithBodies;
+
+  // When intrinsic functions are encountered which require upgrading they are 
+  // stored here with their replacement function.
+  typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
+  UpgradedIntrinsicMap UpgradedIntrinsics;
+
+  // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
+  DenseMap<unsigned, unsigned> MDKindMap;
+  
+  // Several operations happen after the module header has been read, but
+  // before function bodies are processed. This keeps track of whether
+  // we've done this yet.
+  bool SeenFirstFunctionBody;
+  
+  /// DeferredFunctionInfo - When function bodies are initially scanned, this
+  /// map contains info about where to find deferred function body in the
+  /// stream.
+  DenseMap<Function*, uint64_t> DeferredFunctionInfo;
+  
+  /// BlockAddrFwdRefs - These are blockaddr references to basic blocks.  These
+  /// are resolved lazily when functions are loaded.
+  typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
+  DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
+
+public:
+  explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
+    : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
+      LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false) {
+  }
+  explicit BitcodeReader(DataStreamer *streamer, LLVMContext &C)
+    : Context(C), TheModule(0), Buffer(0), BufferOwned(false),
+      LazyStreamer(streamer), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false) {
+  }
+  ~BitcodeReader() {
+    FreeState();
+  }
+
+  void materializeForwardReferencedFunctions();
+
+  void FreeState();
+  
+  /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
+  /// when the reader is destroyed.
+  void setBufferOwned(bool Owned) { BufferOwned = Owned; }
+  
+  virtual bool isMaterializable(const GlobalValue *GV) const;
+  virtual bool isDematerializable(const GlobalValue *GV) const;
+  virtual bool Materialize(GlobalValue *GV, std::string *ErrInfo = 0);
+  virtual bool MaterializeModule(Module *M, std::string *ErrInfo = 0);
+  virtual void Dematerialize(GlobalValue *GV);
+
+  bool Error(const char *Str) {
+    ErrorString = Str;
+    return true;
+  }
+  const char *getErrorString() const { return ErrorString; }
+  
+  /// @brief Main interface to parsing a bitcode buffer.
+  /// @returns true if an error occurred.
+  bool ParseBitcodeInto(Module *M);
+
+  /// @brief Cheap mechanism to just extract module triple
+  /// @returns true if an error occurred.
+  bool ParseTriple(std::string &Triple);
+private:
+  Type *getTypeByID(unsigned ID);
+  Value *getFnValueByID(unsigned ID, Type *Ty) {
+    if (Ty && Ty->isMetadataTy())
+      return MDValueList.getValueFwdRef(ID);
+    return ValueList.getValueFwdRef(ID, Ty);
+  }
+  BasicBlock *getBasicBlock(unsigned ID) const {
+    if (ID >= FunctionBBs.size()) return 0; // Invalid ID
+    return FunctionBBs[ID];
+  }
+  AttrListPtr getAttributes(unsigned i) const {
+    if (i-1 < MAttributes.size())
+      return MAttributes[i-1];
+    return AttrListPtr();
+  }
+  
+  /// getValueTypePair - Read a value/type pair out of the specified record from
+  /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
+  /// Return true on failure.
+  bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
+                        unsigned InstNum, Value *&ResVal) {
+    if (Slot == Record.size()) return true;
+    unsigned ValNo = (unsigned)Record[Slot++];
+    if (ValNo < InstNum) {
+      // If this is not a forward reference, just return the value we already
+      // have.
+      ResVal = getFnValueByID(ValNo, 0);
+      return ResVal == 0;
+    } else if (Slot == Record.size()) {
+      return true;
+    }
+    
+    unsigned TypeNo = (unsigned)Record[Slot++];
+    ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
+    return ResVal == 0;
+  }
+  bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
+                Type *Ty, Value *&ResVal) {
+    if (Slot == Record.size()) return true;
+    unsigned ValNo = (unsigned)Record[Slot++];
+    ResVal = getFnValueByID(ValNo, Ty);
+    return ResVal == 0;
+  }
+
+  
+  bool ParseModule(bool Resume);
+  bool ParseAttributeBlock();
+  bool ParseTypeTable();
+  bool ParseTypeTableBody();
+
+  bool ParseValueSymbolTable();
+  bool ParseConstants();
+  bool RememberAndSkipFunctionBody();
+  bool ParseFunctionBody(Function *F);
+  bool GlobalCleanup();
+  bool ResolveGlobalAndAliasInits();
+  bool ParseMetadata();
+  bool ParseMetadataAttachment();
+  bool ParseModuleTriple(std::string &Triple);
+  bool ParseUseLists();
+  bool InitStream();
+  bool InitStreamFromBuffer();
+  bool InitLazyStream();
+  bool FindFunctionInStream(Function *F,
+         DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator);
+};
+  
+} // End llvm namespace
+
+#endif