From c4e4b7e31e8efc917352286aa6e22d78b659d44d Mon Sep 17 00:00:00 2001
From: Zachary Turner <zturner@google.com>
Date: Thu, 25 May 2017 21:12:00 +0000
Subject: Fix a bug in MappedBlockStream.

It was using the number of blocks of the entire PDB file as the number
of blocks of each stream that was created.  This was only an issue in
the readLongestContiguousChunk function, which  was never called prior.
This bug surfaced when I updated an algorithm to use this function and
the algorithm broke.

llvm-svn: 303916
---
 llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp | 32 +++++++++++++---------------
 1 file changed, 15 insertions(+), 17 deletions(-)

(limited to 'llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp')

diff --git a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
index 57953cfa338..dfdeb841421 100644
--- a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
@@ -45,18 +45,17 @@ static Interval intersect(const Interval &I1, const Interval &I2) {
                         std::min(I1.second, I2.second));
 }
 
-MappedBlockStream::MappedBlockStream(uint32_t BlockSize, uint32_t NumBlocks,
+MappedBlockStream::MappedBlockStream(uint32_t BlockSize,
                                      const MSFStreamLayout &Layout,
                                      BinaryStreamRef MsfData)
-    : BlockSize(BlockSize), NumBlocks(NumBlocks), StreamLayout(Layout),
-      MsfData(MsfData) {}
+    : BlockSize(BlockSize), StreamLayout(Layout), MsfData(MsfData) {}
 
 std::unique_ptr<MappedBlockStream>
-MappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
+MappedBlockStream::createStream(uint32_t BlockSize,
                                 const MSFStreamLayout &Layout,
                                 BinaryStreamRef MsfData) {
   return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
-      BlockSize, NumBlocks, Layout, MsfData);
+      BlockSize, Layout, MsfData);
 }
 
 std::unique_ptr<MappedBlockStream> MappedBlockStream::createIndexedStream(
@@ -66,7 +65,7 @@ std::unique_ptr<MappedBlockStream> MappedBlockStream::createIndexedStream(
   SL.Blocks = Layout.StreamMap[StreamIndex];
   SL.Length = Layout.StreamSizes[StreamIndex];
   return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
-      Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+      Layout.SB->BlockSize, SL, MsfData);
 }
 
 std::unique_ptr<MappedBlockStream>
@@ -75,7 +74,7 @@ MappedBlockStream::createDirectoryStream(const MSFLayout &Layout,
   MSFStreamLayout SL;
   SL.Blocks = Layout.DirectoryBlocks;
   SL.Length = Layout.SB->NumDirectoryBytes;
-  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+  return createStream(Layout.SB->BlockSize, SL, MsfData);
 }
 
 std::unique_ptr<MappedBlockStream>
@@ -83,7 +82,7 @@ MappedBlockStream::createFpmStream(const MSFLayout &Layout,
                                    BinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   initializeFpmStreamLayout(Layout, SL);
-  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+  return createStream(Layout.SB->BlockSize, SL, MsfData);
 }
 
 Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
@@ -173,7 +172,7 @@ Error MappedBlockStream::readLongestContiguousChunk(uint32_t Offset,
   uint32_t First = Offset / BlockSize;
   uint32_t Last = First;
 
-  while (Last < NumBlocks - 1) {
+  while (Last < getNumBlocks() - 1) {
     if (StreamLayout.Blocks[Last] != StreamLayout.Blocks[Last + 1] - 1)
       break;
     ++Last;
@@ -313,17 +312,16 @@ void MappedBlockStream::fixCacheAfterWrite(uint32_t Offset,
 }
 
 WritableMappedBlockStream::WritableMappedBlockStream(
-    uint32_t BlockSize, uint32_t NumBlocks, const MSFStreamLayout &Layout,
+    uint32_t BlockSize, const MSFStreamLayout &Layout,
     WritableBinaryStreamRef MsfData)
-    : ReadInterface(BlockSize, NumBlocks, Layout, MsfData),
-      WriteInterface(MsfData) {}
+    : ReadInterface(BlockSize, Layout, MsfData), WriteInterface(MsfData) {}
 
 std::unique_ptr<WritableMappedBlockStream>
-WritableMappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
+WritableMappedBlockStream::createStream(uint32_t BlockSize,
                                         const MSFStreamLayout &Layout,
                                         WritableBinaryStreamRef MsfData) {
   return llvm::make_unique<MappedBlockStreamImpl<WritableMappedBlockStream>>(
-      BlockSize, NumBlocks, Layout, MsfData);
+      BlockSize, Layout, MsfData);
 }
 
 std::unique_ptr<WritableMappedBlockStream>
@@ -334,7 +332,7 @@ WritableMappedBlockStream::createIndexedStream(const MSFLayout &Layout,
   MSFStreamLayout SL;
   SL.Blocks = Layout.StreamMap[StreamIndex];
   SL.Length = Layout.StreamSizes[StreamIndex];
-  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+  return createStream(Layout.SB->BlockSize, SL, MsfData);
 }
 
 std::unique_ptr<WritableMappedBlockStream>
@@ -343,7 +341,7 @@ WritableMappedBlockStream::createDirectoryStream(
   MSFStreamLayout SL;
   SL.Blocks = Layout.DirectoryBlocks;
   SL.Length = Layout.SB->NumDirectoryBytes;
-  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+  return createStream(Layout.SB->BlockSize, SL, MsfData);
 }
 
 std::unique_ptr<WritableMappedBlockStream>
@@ -351,7 +349,7 @@ WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
                                            WritableBinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   initializeFpmStreamLayout(Layout, SL);
-  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+  return createStream(Layout.SB->BlockSize, SL, MsfData);
 }
 
 Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
-- 
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