From: Zachary Turner <zturner@google.com>
Date: Tue, 6 Jun 2017 23:54:23 +0000 (+0000)
Subject: Fix uninitialized read.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2f4ae78089d093fcb36b8fb98e1cfe249e5c9222;p=llvm

Fix uninitialized read.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304846 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/DebugInfo/PDB/Native/DbiStream.h b/include/llvm/DebugInfo/PDB/Native/DbiStream.h
index dc35f8c72cd..7123e88cd64 100644
--- a/include/llvm/DebugInfo/PDB/Native/DbiStream.h
+++ b/include/llvm/DebugInfo/PDB/Native/DbiStream.h
@@ -96,7 +96,8 @@ private:
 
   FixedStreamArray<support::ulittle16_t> DbgStreams;
 
-  PdbRaw_DbiSecContribVer SectionContribVersion;
+  PdbRaw_DbiSecContribVer SectionContribVersion =
+      PdbRaw_DbiSecContribVer::DbiSecContribVer60;
   FixedStreamArray<SectionContrib> SectionContribs;
   FixedStreamArray<SectionContrib2> SectionContribs2;
   FixedStreamArray<SecMapEntry> SectionMap;
diff --git a/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp b/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
index 22c2ef31bd7..cd69ad3cfc2 100644
--- a/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
+++ b/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
@@ -38,12 +38,12 @@ template <> struct BinaryItemTraits<CVSymbol> {
 
 static uint32_t calculateDiSymbolStreamSize(uint32_t SymbolByteSize,
                                             uint32_t C13Size) {
-  uint32_t Size = sizeof(uint32_t); // Signature
-  Size += SymbolByteSize;           // Symbol Data
-  Size += 0;                        // TODO: Layout.C11Bytes
-  Size += C13Size;                  // C13 Debug Info Size
-  Size += sizeof(uint32_t);         // GlobalRefs substream size (always 0)
-  Size += 0;                        // GlobalRefs substream bytes
+  uint32_t Size = sizeof(uint32_t);   // Signature
+  Size += alignTo(SymbolByteSize, 4); // Symbol Data
+  Size += 0;                          // TODO: Layout.C11Bytes
+  Size += C13Size;                    // C13 Debug Info Size
+  Size += sizeof(uint32_t);           // GlobalRefs substream size (always 0)
+  Size += 0;                          // GlobalRefs substream bytes
   return Size;
 }
 
@@ -156,6 +156,8 @@ Error DbiModuleDescriptorBuilder::commit(BinaryStreamWriter &ModiWriter,
     BinaryStreamRef RecordsRef(Records);
     if (auto EC = SymbolWriter.writeStreamRef(RecordsRef))
       return EC;
+    if (auto EC = SymbolWriter.padToAlignment(4))
+      return EC;
     // TODO: Write C11 Line data
     assert(SymbolWriter.getOffset() % alignOf(CodeViewContainer::Pdb) == 0 &&
            "Invalid debug section alignment!");
diff --git a/lib/DebugInfo/PDB/Native/DbiStream.cpp b/lib/DebugInfo/PDB/Native/DbiStream.cpp
index 320b11dc5ca..24322d942fa 100644
--- a/lib/DebugInfo/PDB/Native/DbiStream.cpp
+++ b/lib/DebugInfo/PDB/Native/DbiStream.cpp
@@ -216,10 +216,12 @@ FixedStreamArray<SecMapEntry> DbiStream::getSectionMap() const {
 
 void DbiStream::visitSectionContributions(
     ISectionContribVisitor &Visitor) const {
-  if (SectionContribVersion == DbiSecContribVer60) {
+  if (!SectionContribs.empty()) {
+    assert(SectionContribVersion == DbiSecContribVer60);
     for (auto &SC : SectionContribs)
       Visitor.visit(SC);
-  } else if (SectionContribVersion == DbiSecContribV2) {
+  } else if (!SectionContribs2.empty()) {
+    assert(SectionContribVersion == DbiSecContribV2);
     for (auto &SC : SectionContribs2)
       Visitor.visit(SC);
   }