From ae7dd8004eb286039ee1eb1a35ddb1ff4eafe460 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 7 Apr 2009 02:56:46 +0000
Subject: [PATCH] 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    | 21 +++++++++---
 tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp | 41 +++++++++++------------
 2 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/include/llvm/Bitcode/BitstreamReader.h b/include/llvm/Bitcode/BitstreamReader.h
index fe51ade4cb3..d64c0dc2ac6 100644
--- a/include/llvm/Bitcode/BitstreamReader.h
+++ b/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.
-        for (; NumElts; ++NextChar, --NumElts)
-          Vals.push_back(*NextChar);
+        // 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
   //===--------------------------------------------------------------------===//
diff --git a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp b/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
index 2953e08afa5..4832a4c0b21 100644
--- a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
+++ b/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)
-        Code = Stream.ReadRecord(AbbrevID, Record);
-      else {
-        Code = Stream.ReadRecord(AbbrevID, Record);
-        BlobStart = BlobStart;
-        BlobLen = BlobLen;
-      }
+      unsigned Code = Stream.ReadRecord(AbbrevID, Record, BlobStart, 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;
-- 
2.34.1