Add an API for the bitstream reader to read blobs and return

them by reference, instead of packing each byte into a
smallvector.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68486 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Bitcode/BitstreamReader.h

@@ -371,7 +371,8 @@ public:
     return CurAbbrevs[AbbrevNo];
   }
   
-  unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals) {
+  unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
+                      const char **BlobStart = 0, unsigned *BlobLen = 0) {
     if (AbbrevID == bitc::UNABBREV_RECORD) {
       unsigned Code = ReadVBR(6);
       unsigned NumElts = ReadVBR(6);
@@ -413,9 +414,15 @@ public:
           break;
         }
         
-        // Otherwise, read the number of bytes.
+        // Otherwise, read the number of bytes.  If we can return a reference to
+        // the data, do so to avoid copying it.
+        if (BlobStart) {
+          *BlobStart = (const char*)NextChar;
+          *BlobLen = NumElts;
+        } else {
           for (; NumElts; ++NextChar, --NumElts)
             Vals.push_back(*NextChar);
+        }
         // Skip over tail padding.
         NextChar = NewEnd;
       } else {
@@ -428,6 +435,12 @@ public:
     return Code;
   }
 
+  unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
+                      const char *&BlobStart, unsigned &BlobLen) {
+    return ReadRecord(AbbrevID, Vals, &BlobStart, &BlobLen);
+  }
+
+  
   //===--------------------------------------------------------------------===//
   // Abbrev Processing
   //===--------------------------------------------------------------------===//

tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

@@ -342,32 +342,14 @@ static bool ParseBlock(BitstreamReader &Stream, unsigned IndentLevel) {
       break;
     default:
       Record.clear();
-      bool HasBlob = false;
 
       ++BlockStats.NumRecords;
-      if (AbbrevID != bitc::UNABBREV_RECORD) {
+      if (AbbrevID != bitc::UNABBREV_RECORD)
         ++BlockStats.NumAbbreviatedRecords;
-        const BitCodeAbbrev *Abbv = Stream.getAbbrev(AbbrevID);
-        if (Abbv->getNumOperandInfos() != 0) {
-          const BitCodeAbbrevOp &LastOp =  
-            Abbv->getOperandInfo(Abbv->getNumOperandInfos()-1);
-          // If the last operand is a blob, then this record has blob data.
-          if (LastOp.isEncoding() && 
-              LastOp.getEncoding() == BitCodeAbbrevOp::Blob)
-            HasBlob = true;
-        }
-      }
         
-      unsigned Code;
       const char *BlobStart = 0;
       unsigned BlobLen = 0;
-      if (!HasBlob)
+      unsigned Code = Stream.ReadRecord(AbbrevID, Record, BlobStart, BlobLen);
-        Code = Stream.ReadRecord(AbbrevID, Record);
-      else {
-        Code = Stream.ReadRecord(AbbrevID, Record);
-        BlobStart = BlobStart;
-        BlobLen = BlobLen;
-      }
 
       // Increment the # occurrences of this code.
       if (BlockStats.CodeFreq.size() <= Code)
@@ -388,7 +370,24 @@ static bool ParseBlock(BitstreamReader &Stream, unsigned IndentLevel) {
         for (unsigned i = 0, e = Record.size(); i != e; ++i)
           std::cerr << " op" << i << "=" << (int64_t)Record[i];
         
-        std::cerr << "/>\n";
+        std::cerr << "/>";
+        
+        if (BlobStart) {
+          std::cerr << " blob data = ";
+          bool BlobIsPrintable = true;
+          for (unsigned i = 0; i != BlobLen; ++i)
+            if (!isprint(BlobStart[i])) {
+              BlobIsPrintable = false;
+              break;
+            }
+          
+          if (BlobIsPrintable)
+            std::cerr << "'" << std::string(BlobStart, BlobStart+BlobLen) <<"'";
+          else
+            std::cerr << "unprintable, " << BlobLen << " bytes.";
+        }
+        
+        std::cerr << "\n";
       }
       
       break;