X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FBitcode%2FReaderWriter.h;h=a186964743dc87026a9ed739ef30feab7724bd10;hb=d928fb670fb3b0818fc23738e9c2418980bb141e;hp=f18b4fc090f6fe80cb8ffcf411e2f9c54927bbd0;hpb=d1ce3b48e24b9e7d78cac590d1e4590a68c2e2ce;p=oota-llvm.git

diff --git a/include/llvm/Bitcode/ReaderWriter.h b/include/llvm/Bitcode/ReaderWriter.h
index f18b4fc090f..a186964743d 100644
--- a/include/llvm/Bitcode/ReaderWriter.h
+++ b/include/llvm/Bitcode/ReaderWriter.h
@@ -14,44 +14,123 @@
 #ifndef LLVM_BITCODE_H
 #define LLVM_BITCODE_H
 
-#include <iosfwd>
 #include <string>
 
 namespace llvm {
   class Module;
-  class ModuleProvider;
   class MemoryBuffer;
   class ModulePass;
+  class BitstreamWriter;
+  class LLVMContext;
   class raw_ostream;
   
-  /// getBitcodeModuleProvider - Read the header of the specified bitcode buffer
+  /// 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.
-  ModuleProvider *getBitcodeModuleProvider(MemoryBuffer *Buffer,
-                                           std::string *ErrMsg = 0);
+  Module *getLazyBitcodeModule(MemoryBuffer *Buffer,
+                               LLVMContext& Context,
+                               std::string *ErrMsg = 0);
 
   /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
   /// If an error occurs, this returns null and fills in *ErrMsg if it is
   /// non-null.  This method *never* takes ownership of Buffer.
-  Module *ParseBitcodeFile(MemoryBuffer *Buffer, std::string *ErrMsg = 0);
-  
-  /// WriteBitcodeToFile - Write the specified module to the specified output
-  /// stream.
-  void WriteBitcodeToFile(const Module *M, std::ostream &Out);
-  
+  Module *ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,
+                           std::string *ErrMsg = 0);
+
   /// WriteBitcodeToFile - Write the specified module to the specified
-  /// raw output stream.
+  /// raw output stream.  For streams where it matters, the given stream
+  /// should be in "binary" mode.
   void WriteBitcodeToFile(const Module *M, raw_ostream &Out);
 
-  /// CreateBitcodeWriterPass - Create and return a pass that writes the module
-  /// to the specified ostream.
-  ModulePass *CreateBitcodeWriterPass(std::ostream &Str);
+  /// WriteBitcodeToStream - Write the specified module to the specified
+  /// raw output stream.
+  void WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream);
 
   /// createBitcodeWriterPass - Create and return a pass that writes the module
   /// to the specified ostream.
   ModulePass *createBitcodeWriterPass(raw_ostream &Str);
+  
+  
+  /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
+  /// for an LLVM IR bitcode wrapper.
+  ///
+  static inline bool isBitcodeWrapper(const unsigned char *BufPtr,
+                                      const unsigned char *BufEnd) {
+    // See if you can find the hidden message in the magic bytes :-).
+    // (Hint: it's a little-endian encoding.)
+    return BufPtr != BufEnd &&
+           BufPtr[0] == 0xDE &&
+           BufPtr[1] == 0xC0 &&
+           BufPtr[2] == 0x17 &&
+           BufPtr[3] == 0x0B;
+  }
+
+  /// isRawBitcode - Return true if the given bytes are the magic bytes for
+  /// raw LLVM IR bitcode (without a wrapper).
+  ///
+  static inline bool isRawBitcode(const unsigned char *BufPtr,
+                                  const unsigned char *BufEnd) {
+    // These bytes sort of have a hidden message, but it's not in
+    // little-endian this time, and it's a little redundant.
+    return BufPtr != BufEnd &&
+           BufPtr[0] == 'B' &&
+           BufPtr[1] == 'C' &&
+           BufPtr[2] == 0xc0 &&
+           BufPtr[3] == 0xde;
+  }
+
+  /// isBitcode - Return true if the given bytes are the magic bytes for
+  /// LLVM IR bitcode, either with or without a wrapper.
+  ///
+  static bool inline isBitcode(const unsigned char *BufPtr,
+                               const unsigned char *BufEnd) {
+    return isBitcodeWrapper(BufPtr, BufEnd) ||
+           isRawBitcode(BufPtr, BufEnd);
+  }
+
+  /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
+  /// header for padding or other reasons.  The format of this header is:
+  ///
+  /// struct bc_header {
+  ///   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) {
+    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))
+      return true;
+    BufPtr += Offset;
+    BufEnd = BufPtr+Size;
+    return false;
+  }
 } // End llvm namespace
 
 #endif