Index: llvm/trunk/include/llvm/DebugInfo/PDB/Raw/DbiStreamBuilder.h
===================================================================
--- llvm/trunk/include/llvm/DebugInfo/PDB/Raw/DbiStreamBuilder.h
+++ llvm/trunk/include/llvm/DebugInfo/PDB/Raw/DbiStreamBuilder.h
@@ -47,6 +47,7 @@
   void setPdbDllRbld(uint16_t R);
   void setFlags(uint16_t F);
   void setMachineType(PDB_Machine M);
+  void setSectionContribs(ArrayRef<SectionContrib> SecMap);
   void setSectionMap(ArrayRef<SecMapEntry> SecMap);
 
   // Add given bytes as a new stream.
@@ -63,6 +64,11 @@
   Error commit(const msf::MSFLayout &Layout,
                const msf::WritableStream &Buffer);
 
+  // A helper function to create Section Contributions from COFF input
+  // section headers.
+  static std::vector<SectionContrib>
+  createSectionContribs(ArrayRef<llvm::object::coff_section> SecHdrs);
+
   // A helper function to create a Section Map from a COFF section header.
   static std::vector<SecMapEntry>
   createSectionMap(ArrayRef<llvm::object::coff_section> SecHdrs);
@@ -75,6 +81,7 @@
 
   Error finalize();
   uint32_t calculateModiSubstreamSize() const;
+  uint32_t calculateSectionContribsStreamSize() const;
   uint32_t calculateSectionMapStreamSize() const;
   uint32_t calculateFileInfoSubstreamSize() const;
   uint32_t calculateNamesBufferSize() const;
@@ -110,6 +117,7 @@
   msf::WritableStreamRef NamesBuffer;
   msf::MutableByteStream ModInfoBuffer;
   msf::MutableByteStream FileInfoBuffer;
+  ArrayRef<SectionContrib> SectionContribs;
   ArrayRef<SecMapEntry> SectionMap;
   llvm::SmallVector<DebugStream, (int)DbgHeaderType::Max> DbgStreams;
 };
Index: llvm/trunk/lib/DebugInfo/PDB/Raw/DbiStreamBuilder.cpp
===================================================================
--- llvm/trunk/lib/DebugInfo/PDB/Raw/DbiStreamBuilder.cpp
+++ llvm/trunk/lib/DebugInfo/PDB/Raw/DbiStreamBuilder.cpp
@@ -46,6 +46,10 @@
 
 void DbiStreamBuilder::setMachineType(PDB_Machine M) { MachineType = M; }
 
+void DbiStreamBuilder::setSectionContribs(ArrayRef<SectionContrib> Arr) {
+  SectionContribs = Arr;
+}
+
 void DbiStreamBuilder::setSectionMap(ArrayRef<SecMapEntry> SecMap) {
   SectionMap = SecMap;
 }
@@ -67,8 +71,8 @@
 uint32_t DbiStreamBuilder::calculateSerializedLength() const {
   // For now we only support serializing the header.
   return sizeof(DbiStreamHeader) + calculateFileInfoSubstreamSize() +
-         calculateModiSubstreamSize() + calculateSectionMapStreamSize() +
-         calculateDbgStreamsSize();
+         calculateModiSubstreamSize() + calculateSectionContribsStreamSize() +
+         calculateSectionMapStreamSize() + calculateDbgStreamsSize();
 }
 
 Error DbiStreamBuilder::addModuleInfo(StringRef ObjFile, StringRef Module) {
@@ -106,6 +110,13 @@
   return Size;
 }
 
+uint32_t DbiStreamBuilder::calculateSectionContribsStreamSize() const {
+  if (SectionContribs.empty())
+    return 0;
+  return sizeof(enum PdbRaw_DbiSecContribVer) +
+         sizeof(SectionContribs[0]) * SectionContribs.size();
+};
+
 uint32_t DbiStreamBuilder::calculateSectionMapStreamSize() const {
   if (SectionMap.empty())
     return 0;
@@ -249,7 +260,7 @@
   H->FileInfoSize = FileInfoBuffer.getLength();
   H->ModiSubstreamSize = ModInfoBuffer.getLength();
   H->OptionalDbgHdrSize = DbgStreams.size() * sizeof(uint16_t);
-  H->SecContrSubstreamSize = 0;
+  H->SecContrSubstreamSize = calculateSectionContribsStreamSize();
   H->SectionMapSize = calculateSectionMapStreamSize();
   H->TypeServerSize = 0;
   H->SymRecordStreamIndex = kInvalidStreamIndex;
@@ -287,6 +298,25 @@
   return Ret;
 }
 
+// A utility function to create Section Contributions
+// for a given input sections.
+std::vector<SectionContrib> DbiStreamBuilder::createSectionContribs(
+    ArrayRef<object::coff_section> SecHdrs) {
+  std::vector<SectionContrib> Ret;
+
+  // Create a SectionContrib for each input section.
+  for (auto &Sec : SecHdrs) {
+    Ret.emplace_back();
+    auto &Entry = Ret.back();
+    memset(&Entry, 0, sizeof(Entry));
+
+    Entry.Off = Sec.PointerToRawData;
+    Entry.Size = Sec.SizeOfRawData;
+    Entry.Characteristics = Sec.Characteristics;
+  }
+  return Ret;
+}
+
 // A utility function to create a Section Map for a given list of COFF sections.
 //
 // A Section Map seem to be a copy of a COFF section list in other format.
@@ -363,6 +393,13 @@
   if (auto EC = Writer.writeStreamRef(ModInfoBuffer))
     return EC;
 
+  if (!SectionContribs.empty()) {
+    if (auto EC = Writer.writeEnum(DbiSecContribVer60))
+      return EC;
+    if (auto EC = Writer.writeArray(SectionContribs))
+      return EC;
+  }
+
   if (!SectionMap.empty()) {
     ulittle16_t Size = static_cast<ulittle16_t>(SectionMap.size());
     SecMapHeader SMHeader = {Size, Size};