From dc1414b3f950cb389775b634706a6635535ed825 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Sat, 6 Feb 2016 00:46:09 +0000
Subject: [PATCH] llvm-bcanalyzer: Produce summary information for the
 BLOCKINFO block, it can be a significant fraction of the file size (for files
 that otherwise have few records). Also include an average size per record in
 the summary information.

llvm-svn: 259965
---
 llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp | 27 ++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp b/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
index 48523f9..1a4bc9e 100644
--- a/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
+++ b/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
@@ -406,13 +406,13 @@ static bool ParseBlock(BitstreamCursor &Stream, unsigned BlockID,
   BlockStats.NumInstances++;
 
   // BLOCKINFO is a special part of the stream.
+  bool DumpRecords = Dump;
   if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
     if (Dump) outs() << Indent << "<BLOCKINFO_BLOCK/>\n";
-    if (Stream.ReadBlockInfoBlock())
+    if (BitstreamCursor(Stream).ReadBlockInfoBlock())
       return Error("Malformed BlockInfoBlock");
-    uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
-    BlockStats.NumBits += BlockBitEnd-BlockBitStart;
-    return false;
+    // It's not really interesting to dump the contents of the blockinfo block.
+    DumpRecords = false;
   }
 
   unsigned NumWords = 0;
@@ -420,7 +420,7 @@ static bool ParseBlock(BitstreamCursor &Stream, unsigned BlockID,
     return Error("Malformed block record");
 
   const char *BlockName = nullptr;
-  if (Dump) {
+  if (DumpRecords) {
     outs() << Indent << "<";
     if ((BlockName = GetBlockName(BlockID, *Stream.getBitStreamReader(),
                                   CurStreamType)))
@@ -453,7 +453,7 @@ static bool ParseBlock(BitstreamCursor &Stream, unsigned BlockID,
     case BitstreamEntry::EndBlock: {
       uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
       BlockStats.NumBits += BlockBitEnd-BlockBitStart;
-      if (Dump) {
+      if (DumpRecords) {
         outs() << Indent << "</";
         if (BlockName)
           outs() << BlockName << ">\n";
@@ -503,7 +503,7 @@ static bool ParseBlock(BitstreamCursor &Stream, unsigned BlockID,
       ++BlockStats.NumAbbreviatedRecords;
     }
 
-    if (Dump) {
+    if (DumpRecords) {
       outs() << Indent << "  <";
       if (const char *CodeName =
             GetCodeName(Code, BlockID, *Stream.getBitStreamReader(),
@@ -764,7 +764,7 @@ static int AnalyzeBitcode() {
       std::reverse(FreqPairs.begin(), FreqPairs.end());
 
       outs() << "\tRecord Histogram:\n";
-      outs() << "\t\t  Count    # Bits   %% Abv  Record Kind\n";
+      outs() << "\t\t  Count    # Bits     b/Rec   % Abv  Record Kind\n";
       for (unsigned i = 0, e = FreqPairs.size(); i != e; ++i) {
         const PerRecordStats &RecStats = Stats.CodeFreq[FreqPairs[i].second];
 
@@ -772,13 +772,20 @@ static int AnalyzeBitcode() {
                          RecStats.NumInstances,
                          (unsigned long)RecStats.TotalBits);
 
+        if (RecStats.NumInstances > 1)
+          outs() << format(" %9.1f",
+                           (double)RecStats.TotalBits/RecStats.NumInstances);
+        else
+          outs() << "          ";
+
         if (RecStats.NumAbbrev)
           outs() <<
-              format("%7.2f  ",
+              format(" %7.2f",
                      (double)RecStats.NumAbbrev/RecStats.NumInstances*100);
         else
-          outs() << "         ";
+          outs() << "        ";
 
+        outs() << "  ";
         if (const char *CodeName =
               GetCodeName(FreqPairs[i].second, I->first, StreamFile,
                           CurStreamType))
-- 
2.7.4