Fix uninitialized read.

llvm-svn: 304846

1 files changed, 8 insertions, 6 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
index 22c2ef31bd7..cd69ad3cfc2 100644
--- a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
+++ b/llvm/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!");