Initial support for reading bitcode files. They currently only read types,

the type symtab, and global/function protos, and are missing the important
size optimization, but it is a place to start.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36330 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Reader/BitcodeReader.h

@@ -0,0 +1,66 @@
+//===- BitcodeReader.h - Internal BitcodeReader impl ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and 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/AbstractTypeUser.h"
+#include "llvm/ModuleProvider.h"
+#include "../LLVMBitCodes.h"
+#include <vector>
+
+namespace llvm {
+  class BitstreamReader;
+
+class BitcodeReader : public ModuleProvider {
+  const char *ErrorString;
+  
+  std::vector<PATypeHolder> TypeList;
+public:
+  virtual ~BitcodeReader() {}
+  
+  virtual void FreeState() {}
+  
+  virtual bool materializeFunction(Function *F, std::string *ErrInfo = 0) {
+    // FIXME: TODO
+    return false;
+  }
+  
+  virtual Module *materializeModule(std::string *ErrInfo = 0) {
+    // FIXME: TODO
+    //if (ParseAllFunctionBodies(ErrMsg))
+    //  return 0;
+    return TheModule;
+  }
+  
+  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 ParseBitcode(unsigned char *Buf, unsigned Length,
+                    const std::string &ModuleID);
+private:
+  const Type *getTypeByID(unsigned ID, bool isTypeTable = false);
+  
+  bool ParseModule(BitstreamReader &Stream, const std::string &ModuleID);
+  bool ParseTypeTable(BitstreamReader &Stream);
+  bool ParseTypeSymbolTable(BitstreamReader &Stream);
+};
+  
+} // End llvm namespace
+
+#endif