Bitcode streaming

include/llvm/Bitcode/ReaderWriter.h

 //===-- llvm/Bitcode/ReaderWriter.h - Bitcode reader/writers ----*- 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 interfaces to read and write LLVM bitcode files/streams.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_BITCODE_H
 #define LLVM_BITCODE_H
 
+#include "llvm/Bitcode/BitcodeStream.h"
 #include <string>
 
 namespace llvm {
   class Module;
   class MemoryBuffer;
   class ModulePass;
   class BitstreamWriter;
   class LLVMContext;
   class raw_ostream;
   
   /// getLazyBitcodeModule - Read the header of the specified bitcode buffer
   /// and prepare for lazy deserialization of function bodies.  If successful,
   /// this takes ownership of 'buffer' and returns a non-null pointer.  On
   /// error, this returns null, *does not* take ownership of Buffer, and fills
   /// in *ErrMsg with an error description if ErrMsg is non-null.
   Module *getLazyBitcodeModule(MemoryBuffer *Buffer,
                                LLVMContext& Context,
                                std::string *ErrMsg = 0);
 
+  /// Like getLazyBitcodeModule, except it calls cb to get chunks of the
+  /// bitcode instead of needing the whole buffer ahead of time.
+  Module *getLazyBitcodeStreamModule(const std::string &name,
+                                     StreamChunkCallback cb,
+                                     LLVMContext& Context,
+                                     std::string *ErrMsg = 0);
+
   /// getBitcodeTargetTriple - Read the header of the specified bitcode
   /// buffer and extract just the triple information. If successful,
   /// this returns a string and *does not* take ownership
   /// of 'buffer'. On error, this returns "", and fills in *ErrMsg
   /// if ErrMsg is non-null.
   std::string getBitcodeTargetTriple(MemoryBuffer *Buffer,
                                      LLVMContext& Context,
                                      std::string *ErrMsg = 0);
 
   /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
@@ skipping 60 matching lines @@
   ///   uint32_t Magic;         // 0x0B17C0DE
   ///   uint32_t Version;       // Version, currently always 0.
   ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
   ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
   ///   ... potentially other gunk ...
   /// };
   /// 
   /// This function is called when we find a file with a matching magic number.
   /// In this case, skip down to the subsection of the file that is actually a
   /// BC file.
-  static inline bool SkipBitcodeWrapperHeader(unsigned char *&BufPtr,
-                                              unsigned char *&BufEnd) {
+  /// If 'verify' is true, check that the file fits in the buffer.
+  static inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
+                                              const unsigned char *&BufEnd,
+                                              bool Verify) {
     enum {
       KnownHeaderSize = 4*4,  // Size of header we read.
       OffsetField = 2*4,      // Offset in bytes to Offset field.
       SizeField = 3*4         // Offset in bytes to Size field.
     };
     
     // Must contain the header!
     if (BufEnd-BufPtr < KnownHeaderSize) return true;
     
     unsigned Offset = ( BufPtr[OffsetField  ]        |
                        (BufPtr[OffsetField+1] << 8)  |
                        (BufPtr[OffsetField+2] << 16) |
                        (BufPtr[OffsetField+3] << 24));
     unsigned Size   = ( BufPtr[SizeField    ]        |
                        (BufPtr[SizeField  +1] << 8)  |
                        (BufPtr[SizeField  +2] << 16) |
                        (BufPtr[SizeField  +3] << 24));
     
     // Verify that Offset+Size fits in the file.
-    if (Offset+Size > unsigned(BufEnd-BufPtr))
+    if (Verify && Offset+Size > unsigned(BufEnd-BufPtr))
       return true;
     BufPtr += Offset;
     BufEnd = BufPtr+Size;
     return false;
   }
 } // End llvm namespace
 
 #endif