Teach llvm-bcanalyzer to skip over the header we use on LLVM IR files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68458 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Bitcode/ReaderWriter.h b/include/llvm/Bitcode/ReaderWriter.h
index ce5c29cf9f64eb25fa476b18ad12c329e3794954..abdd5d3d8b1945e4f7071ccbfe0029ddefb50022 100644 (file)
--- a/include/llvm/Bitcode/ReaderWriter.h
+++ b/include/llvm/Bitcode/ReaderWriter.h
@@ -24,7 +24,7 @@ namespace llvm {
   class ModulePass;
   class BitstreamWriter;
   class raw_ostream;
-
+  
   /// getBitcodeModuleProvider - 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
@@ -57,6 +57,57 @@ namespace llvm {
   /// createBitcodeWriterPass - Create and return a pass that writes the module
   /// to the specified ostream.
   ModulePass *createBitcodeWriterPass(raw_ostream &Str);
+  
+  
+  /// isBitcodeWrapper - Return true fi this is a wrapper for LLVM IR bitcode
+  /// files.
+  static bool inline isBitcodeWrapper(unsigned char *BufPtr,
+                                      unsigned char *BufEnd) {
+    return (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 && 
+            BufPtr[2] == 0x17 && BufPtr[3] == 0x0B);
+  }
+  
+  /// 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

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 66ccdc2f90d195a45c3dce35476093a646cd37af..6f91dda50128407751a0a88937b51c1fd7150d65 100644 (file)
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1330,48 +1330,6 @@ bool BitcodeReader::ParseModule(const std::string &ModuleID) {
   return Error("Premature end of bitstream");
 }
 
-/// SkipWrapperHeader - 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 bool SkipWrapperHeader(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;
-}
-
 bool BitcodeReader::ParseBitcode() {
   TheModule = 0;
   
@@ -1383,9 +1341,8 @@ bool BitcodeReader::ParseBitcode() {
   
   // If we have a wrapper header, parse it and ignore the non-bc file contents.
   // The magic number is 0x0B17C0DE stored in little endian.
-  if (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 && 
-      BufPtr[2] == 0x17 && BufPtr[3] == 0x0B)
-    if (SkipWrapperHeader(BufPtr, BufEnd))
+  if (isBitcodeWrapper(BufPtr, BufEnd))
+    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
       return Error("Invalid bitcode wrapper header");
   
   Stream.init(BufPtr, BufEnd);

diff --git a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp b/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
index 52a198ae790f8fe81d0dee1f522d6c56dc1a014a..cde27fac48ce2ec0a128ecfd380149da3c5bfd05 100644 (file)
--- a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
+++ b/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
@@ -30,6 +30,7 @@
 #include "llvm/Analysis/Verifier.h"
 #include "llvm/Bitcode/BitstreamReader.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
+#include "llvm/Bitcode/ReaderWriter.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -382,16 +383,24 @@ static void PrintSize(double Bits) {
 /// AnalyzeBitcode - Analyze the bitcode file specified by InputFilename.
 static int AnalyzeBitcode() {
   // Read the input file.
-  MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(InputFilename.c_str());
+  MemoryBuffer *MemBuf = MemoryBuffer::getFileOrSTDIN(InputFilename.c_str());
 
-  if (Buffer == 0)
+  if (MemBuf == 0)
     return Error("Error reading '" + InputFilename + "'.");
   
-  if (Buffer->getBufferSize() & 3)
+  if (MemBuf->getBufferSize() & 3)
     return Error("Bitcode stream should be a multiple of 4 bytes in length");
   
-  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
-  BitstreamReader Stream(BufPtr, BufPtr+Buffer->getBufferSize());
+  unsigned char *BufPtr = (unsigned char *)MemBuf->getBufferStart();
+  unsigned char *EndBufPtr = BufPtr+MemBuf->getBufferSize();
+  
+  // If we have a wrapper header, parse it and ignore the non-bc file contents.
+  // The magic number is 0x0B17C0DE stored in little endian.
+  if (isBitcodeWrapper(BufPtr, EndBufPtr))
+    if (SkipBitcodeWrapperHeader(BufPtr, EndBufPtr))
+      return Error("Invalid bitcode wrapper header");
+  
+  BitstreamReader Stream(BufPtr, EndBufPtr);
 
   
   // Read the stream signature.
@@ -425,7 +434,7 @@ static int AnalyzeBitcode() {
   
   if (Dump) std::cerr << "\n\n";
   
-  uint64_t BufferSizeBits = Buffer->getBufferSize()*CHAR_BIT;
+  uint64_t BufferSizeBits = (EndBufPtr-BufPtr)*CHAR_BIT;
   // Print a summary of the read file.
   std::cerr << "Summary of " << InputFilename << ":\n";
   std::cerr << "         Total size: ";