diff --git a/include/llvm/MC/MCSectionCOFF.h b/include/llvm/MC/MCSectionCOFF.h
index a428f9efb2b..33ba45c2783 100644
--- a/include/llvm/MC/MCSectionCOFF.h
+++ b/include/llvm/MC/MCSectionCOFF.h
@@ -76,6 +76,7 @@ class MCSymbol;
       return SectionName.str() + "_end";
     }
     unsigned getCharacteristics() const { return Characteristics; }
+    const MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; }
     int getSelection() const { return Selection; }
     const MCSectionCOFF *getAssocSection() const { return Assoc; }
 
diff --git a/lib/MC/WinCOFFObjectWriter.cpp b/lib/MC/WinCOFFObjectWriter.cpp
index 961cbc6a8f7..c3fc61b2904 100644
--- a/lib/MC/WinCOFFObjectWriter.cpp
+++ b/lib/MC/WinCOFFObjectWriter.cpp
@@ -347,6 +347,11 @@ void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
 
   COFFSection *coff_section = createSection(Sec.getSectionName());
   COFFSymbol  *coff_symbol = createSymbol(Sec.getSectionName());
+  if (const MCSymbol *S = Sec.getCOMDATSymbol()) {
+    COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(S);
+    assert(!COMDATSymbol->Section);
+    COMDATSymbol->Section = coff_section;
+  }
 
   coff_section->Symbol = coff_symbol;
   coff_symbol->Section = coff_section;
@@ -458,9 +463,15 @@ void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
       coff_symbol->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
     } else {
       const MCSymbolData &BaseData = Assembler.getSymbolData(*Base);
-      if (BaseData.Fragment)
-        coff_symbol->Section =
+      if (BaseData.Fragment) {
+        COFFSection *Sec =
             SectionMap[&BaseData.Fragment->getParent()->getSection()];
+
+        if (coff_symbol->Section && coff_symbol->Section != Sec)
+          report_fatal_error("conflicting sections for symbol");
+
+        coff_symbol->Section = Sec;
+      }
     }
 
     coff_symbol->MCData = &ResSymData;
diff --git a/test/MC/COFF/section-comdat-conflict.s b/test/MC/COFF/section-comdat-conflict.s
new file mode 100644
index 00000000000..7ed452a5cdc
--- /dev/null
+++ b/test/MC/COFF/section-comdat-conflict.s
@@ -0,0 +1,13 @@
+// RUN: not llvm-mc -triple i386-pc-win32 -filetype=obj < %s 2>&1 |  FileCheck %s
+
+// CHECK: conflicting sections for symbol
+
+        .section .xyz
+        .global bar
+bar:
+        .long 42
+
+        .section        .abcd,"xr",discard,bar
+        .global foo
+foo:
+        .long 42
diff --git a/test/MC/COFF/section-comdat.s b/test/MC/COFF/section-comdat.s
index dd5be871b05..e166a508bc1 100644
--- a/test/MC/COFF/section-comdat.s
+++ b/test/MC/COFF/section-comdat.s
@@ -40,6 +40,11 @@ Symbol6:
 Symbol7:
 .long 1
 
+.section SecName, "dr", newest, "Symbol8"
+.globl AnotherSymbol
+AnotherSymbol:
+.long 1
+
 // CHECK: Sections [
 // CHECK:   Section {
 // CHECK:     Number: 1
@@ -114,6 +119,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol1
+// CHECK:     Section: secName (2)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: secName
 // CHECK:     Section: secName (3)
 // CHECK:     AuxSectionDef {
@@ -121,6 +130,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol2
+// CHECK:     Section: secName (3)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (4)
 // CHECK:     AuxSectionDef {
@@ -128,6 +141,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol3
+// CHECK:     Section: SecName (4)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (5)
 // CHECK:     AuxSymbolCount: 1
@@ -136,6 +153,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol4
+// CHECK:     Section: SecName (5)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (6)
 // CHECK:     AuxSectionDef {
@@ -144,6 +165,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol5
+// CHECK:     Section: SecName (6)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (7)
 // CHECK:     AuxSectionDef {
@@ -151,6 +176,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol6
+// CHECK:     Section: SecName (7)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (8)
 // CHECK:     AuxSectionDef {
@@ -158,31 +187,22 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
-// CHECK:     Name: Symbol1
-// CHECK:     Section: secName (2)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol2
-// CHECK:     Section: secName (3)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol3
-// CHECK:     Section: SecName (4)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol4
-// CHECK:     Section: SecName (5)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol5
-// CHECK:     Section: SecName (6)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol6
-// CHECK:     Section: SecName (7)
-// CHECK:   }
-// CHECK:   Symbol {
 // CHECK:     Name: Symbol7
 // CHECK:     Section: SecName (8)
 // CHECK:   }
+// CHECK:   Symbol {
+// CHECK:     Name: SecName
+// CHECK:     Section: SecName (9)
+// CHECK:     AuxSectionDef {
+// CHECK:       Selection: Newest (0x7)
+// CHECK:     }
+// CHECK:   }
+// CHECK:   Symbol {
+// CHECK:     Name: Symbol8
+// CHECK:     Section: SecName (9)
+// CHECK:   }
+// CHECK:   Symbol {
+// CHECK:     Name: AnotherSymbol
+// CHECK:     Section: SecName (9)
+// CHECK:   }
 // CHECK: ]