diff --git a/llvm/include/llvm/DWARFLinker/DWARFLinker.h b/llvm/include/llvm/DWARFLinker/DWARFLinker.h
--- a/llvm/include/llvm/DWARFLinker/DWARFLinker.h
+++ b/llvm/include/llvm/DWARFLinker/DWARFLinker.h
@@ -371,6 +371,8 @@
     /// Given a DIE, update its incompleteness based on whether the DIEs it
     /// references are incomplete.
     UpdateRefIncompleteness,
+    /// Given a DIE, mark it as ODR Canonical if applicable.
+    MarkODRCanonicalDie,
   };
 
   /// This class represents an item in the work list. The type defines what kind
@@ -470,6 +472,10 @@
                             const DWARFFile &File,
                             SmallVectorImpl<WorklistItem> &Worklist);
 
+  /// Mark context corresponding to the specified \p Die as having canonical
+  /// die, if applicable.
+  void markODRCanonicalDie(const DWARFDie &Die, CompileUnit &CU);
+
   /// \defgroup FindRootDIEs Find DIEs corresponding to Address map entries.
   ///
   /// @{
diff --git a/llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h b/llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h
--- a/llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h
+++ b/llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h
@@ -74,6 +74,12 @@
 
     /// Does DIE transitively refer an incomplete decl?
     bool Incomplete : 1;
+
+    /// Is DIE in the clang module scope?
+    bool InModuleScope : 1;
+
+    /// Is ODR marking done?
+    bool ODRMarkingDone : 1;
   };
 
   CompileUnit(DWARFUnit &OrigUnit, unsigned ID, bool CanUseODR,
diff --git a/llvm/include/llvm/DWARFLinker/DWARFLinkerDeclContext.h b/llvm/include/llvm/DWARFLinker/DWARFLinkerDeclContext.h
--- a/llvm/include/llvm/DWARFLinker/DWARFLinkerDeclContext.h
+++ b/llvm/include/llvm/DWARFLinker/DWARFLinkerDeclContext.h
@@ -18,6 +18,7 @@
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include <atomic>
 
 namespace llvm {
 
@@ -91,6 +92,10 @@
 
   bool setLastSeenDIE(CompileUnit &U, const DWARFDie &Die);
 
+  void setHasCanonicalDIE() { HasCanonicalDIE = true; }
+
+  bool hasCanonicalDIE() const { return HasCanonicalDIE; }
+
   uint32_t getCanonicalDIEOffset() const { return CanonicalDIEOffset; }
   void setCanonicalDIEOffset(uint32_t Offset) { CanonicalDIEOffset = Offset; }
 
@@ -112,7 +117,8 @@
   const DeclContext &Parent;
   DWARFDie LastSeenDIE;
   uint32_t LastSeenCompileUnitID = 0;
-  uint32_t CanonicalDIEOffset = 0;
+  std::atomic<uint32_t> CanonicalDIEOffset = {0};
+  bool HasCanonicalDIE = false;
 };
 
 /// This class gives a tree-like API to the DenseMap that stores the
diff --git a/llvm/lib/DWARFLinker/DWARFLinker.cpp b/llvm/lib/DWARFLinker/DWARFLinker.cpp
--- a/llvm/lib/DWARFLinker/DWARFLinker.cpp
+++ b/llvm/lib/DWARFLinker/DWARFLinker.cpp
@@ -361,16 +361,16 @@
     }
 
     Info.ParentIdx = Current.ParentIdx;
-    bool InClangModule = CU.isClangModule() || Current.InImportedModule;
-    if (CU.hasODR() || InClangModule) {
+    Info.InModuleScope = CU.isClangModule() || Current.InImportedModule;
+    if (CU.hasODR() || Info.InModuleScope) {
       if (Current.Context) {
         auto PtrInvalidPair = Contexts.getChildDeclContext(
-            *Current.Context, Current.Die, CU, InClangModule);
+            *Current.Context, Current.Die, CU, Info.InModuleScope);
         Current.Context = PtrInvalidPair.getPointer();
         Info.Ctxt =
             PtrInvalidPair.getInt() ? nullptr : PtrInvalidPair.getPointer();
         if (Info.Ctxt)
-          Info.Ctxt->setDefinedInClangModule(InClangModule);
+          Info.Ctxt->setDefinedInClangModule(Info.InModuleScope);
       } else
         Info.Ctxt = Current.Context = nullptr;
     }
@@ -617,6 +617,27 @@
   }
 }
 
+static bool isODRCanonicalCandidate(const DWARFDie &Die, CompileUnit &CU) {
+  CompileUnit::DIEInfo &Info = CU.getInfo(Die);
+
+  if (!Info.Ctxt || (Die.getTag() == dwarf::DW_TAG_namespace))
+    return false;
+
+  if (!CU.hasODR() && !Info.InModuleScope)
+    return false;
+
+  return !Info.Incomplete && Info.Ctxt != CU.getInfo(Info.ParentIdx).Ctxt;
+}
+
+void DWARFLinker::markODRCanonicalDie(const DWARFDie &Die, CompileUnit &CU) {
+  CompileUnit::DIEInfo &Info = CU.getInfo(Die);
+
+  Info.ODRMarkingDone = true;
+  if (Info.Keep && isODRCanonicalCandidate(Die, CU) &&
+      !Info.Ctxt->hasCanonicalDIE())
+    Info.Ctxt->setHasCanonicalDIE();
+}
+
 /// Look at DIEs referenced by the given DIE and decide whether they should be
 /// kept. All DIEs referenced though attributes should be kept.
 void DWARFLinker::lookForRefDIEsToKeep(
@@ -646,8 +667,6 @@
     if (auto RefDie =
             resolveDIEReference(File, Units, Val, Die, ReferencedCU)) {
       CompileUnit::DIEInfo &Info = ReferencedCU->getInfo(RefDie);
-      bool IsModuleRef = Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset() &&
-                         Info.Ctxt->isDefinedInClangModule();
       // If the referenced DIE has a DeclContext that has already been
       // emitted, then do not keep the one in this CU. We'll link to
       // the canonical DIE in cloneDieReferenceAttribute.
@@ -658,15 +677,14 @@
       //
       // FIXME: compatibility with dsymutil-classic. There is no
       // reason not to unique ref_addr references.
-      if (AttrSpec.Form != dwarf::DW_FORM_ref_addr && (UseOdr || IsModuleRef) &&
-          Info.Ctxt &&
-          Info.Ctxt != ReferencedCU->getInfo(Info.ParentIdx).Ctxt &&
-          Info.Ctxt->getCanonicalDIEOffset() && isODRAttribute(AttrSpec.Attr))
+      if (AttrSpec.Form != dwarf::DW_FORM_ref_addr &&
+          isODRAttribute(AttrSpec.Attr) && Info.Ctxt &&
+          Info.Ctxt->hasCanonicalDIE())
         continue;
 
       // Keep a module forward declaration if there is no definition.
       if (!(isODRAttribute(AttrSpec.Attr) && Info.Ctxt &&
-            Info.Ctxt->getCanonicalDIEOffset()))
+            Info.Ctxt->hasCanonicalDIE()))
         Info.Prune = false;
       ReferencedDIEs.emplace_back(RefDie, *ReferencedCU);
     }
@@ -757,6 +775,9 @@
       lookForParentDIEsToKeep(Current.AncestorIdx, Current.CU, Current.Flags,
                               Worklist);
       continue;
+    case WorklistItemType::MarkODRCanonicalDie:
+      markODRCanonicalDie(Current.Die, Current.CU);
+      continue;
     case WorklistItemType::LookForDIEsToKeep:
       break;
     }
@@ -779,6 +800,16 @@
       Current.Flags = shouldKeepDIE(AddressesMap, Ranges, Current.Die, File,
                                     Current.CU, MyInfo, Current.Flags);
 
+    // We need to mark context for the canonical die in the end of normal
+    // traversing(not TF_DependencyWalk) or after normal traversing if die
+    // was not marked as kept.
+    if (!(Current.Flags & TF_DependencyWalk) ||
+        (MyInfo.ODRMarkingDone && !MyInfo.Keep)) {
+      if (Current.CU.hasODR() || MyInfo.InModuleScope)
+        Worklist.emplace_back(Current.Die, Current.CU,
+                              WorklistItemType::MarkODRCanonicalDie);
+    }
+
     // Finish by looking for child DIEs. Because of the LIFO worklist we need
     // to schedule that work before any subsequent items are added to the
     // worklist.
@@ -846,7 +877,7 @@
 
 unsigned DWARFLinker::DIECloner::cloneStringAttribute(
     DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val,
-    const DWARFUnit &U, OffsetsStringPool &StringPool, AttributesInfo &Info) {
+    const DWARFUnit &, OffsetsStringPool &StringPool, AttributesInfo &Info) {
   Optional<const char *> String = dwarf::toString(Val);
   if (!String)
     return 0;
@@ -876,7 +907,6 @@
 
   DIE *NewRefDie = nullptr;
   CompileUnit *RefUnit = nullptr;
-  DeclContext *Ctxt = nullptr;
 
   DWARFDie RefDie =
       Linker.resolveDIEReference(File, CompileUnits, Val, InputDIE, RefUnit);
@@ -889,14 +919,14 @@
 
   // If we already have emitted an equivalent DeclContext, just point
   // at it.
-  if (isODRAttribute(AttrSpec.Attr)) {
-    Ctxt = RefInfo.Ctxt;
-    if (Ctxt && Ctxt->getCanonicalDIEOffset()) {
-      DIEInteger Attr(Ctxt->getCanonicalDIEOffset());
-      Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
-                   dwarf::DW_FORM_ref_addr, Attr);
-      return U.getRefAddrByteSize();
-    }
+  if (isODRAttribute(AttrSpec.Attr) && RefInfo.Ctxt &&
+      RefInfo.Ctxt->getCanonicalDIEOffset()) {
+    assert(RefInfo.Ctxt->hasCanonicalDIE() &&
+           "Offset to canonical die is set, but context is not marked");
+    DIEInteger Attr(RefInfo.Ctxt->getCanonicalDIEOffset());
+    Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
+                 dwarf::DW_FORM_ref_addr, Attr);
+    return U.getRefAddrByteSize();
   }
 
   if (!RefInfo.Clone) {
@@ -926,7 +956,7 @@
       // A forward reference. Note and fixup later.
       Attr = 0xBADDEF;
       Unit.noteForwardReference(
-          NewRefDie, RefUnit, Ctxt,
+          NewRefDie, RefUnit, RefInfo.Ctxt,
           Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
                        dwarf::DW_FORM_ref_addr, DIEInteger(Attr)));
     }
@@ -1357,10 +1387,10 @@
 
   assert(Die->getTag() == InputDIE.getTag());
   Die->setOffset(OutOffset);
-  if ((Unit.hasODR() || Unit.isClangModule()) && !Info.Incomplete &&
-      Die->getTag() != dwarf::DW_TAG_namespace && Info.Ctxt &&
-      Info.Ctxt != Unit.getInfo(Info.ParentIdx).Ctxt &&
-      !Info.Ctxt->getCanonicalDIEOffset()) {
+  if (isODRCanonicalCandidate(InputDIE, Unit) && Info.Ctxt &&
+      (Info.Ctxt->getCanonicalDIEOffset() == 0)) {
+    if (!Info.Ctxt->hasCanonicalDIE())
+      Info.Ctxt->setHasCanonicalDIE();
     // We are about to emit a DIE that is the root of its own valid
     // DeclContext tree. Make the current offset the canonical offset
     // for this context.
diff --git a/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp b/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
--- a/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
+++ b/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
@@ -90,9 +90,11 @@
     PatchLocation Attr;
     DeclContext *Ctxt;
     std::tie(RefDie, RefUnit, Ctxt, Attr) = Ref;
-    if (Ctxt && Ctxt->getCanonicalDIEOffset())
+    if (Ctxt && Ctxt->hasCanonicalDIE()) {
+      assert(Ctxt->getCanonicalDIEOffset() &&
+             "Canonical die offset is not set");
       Attr.set(Ctxt->getCanonicalDIEOffset());
-    else
+    } else
       Attr.set(RefDie->getOffset() + RefUnit->getStartOffset());
   }
 }
diff --git a/llvm/test/tools/dsymutil/X86/odr-two-units-in-single-file.test b/llvm/test/tools/dsymutil/X86/odr-two-units-in-single-file.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/odr-two-units-in-single-file.test
@@ -0,0 +1,200 @@
+## This test checks debug info for the types located into the
+## different compilation units from the single object file.
+## Type definition for the "class1" should be removed from the
+## second compilation unit.
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: echo '---' > %t2.map
+# RUN: echo "triple:          'x86_64-apple-darwin'" >> %t2.map
+# RUN: echo 'objects:'  >> %t2.map
+# RUN: echo " -  filename: '%t.o'" >> %t2.map
+# RUN: echo '    symbols:' >> %t2.map
+# RUN: echo '      - { sym: __Z3foov, objAddr: 0x0, binAddr: 0x10000, size: 0x10 }' >> %t2.map
+# RUN: echo '...' >> %t2.map
+# RUN: dsymutil -y %t2.map -f -o - | llvm-dwarfdump -a - | FileCheck %s
+
+# CHECK: file format Mach-O 64-bit x86-64
+# CHECK: .debug_info contents:
+# CHECK: Compile Unit:
+# CHECK: DW_TAG_compile_unit
+# CHECK: DW_AT_name{{.*}}"CU1"
+# CHECK: DW_TAG_class_type{{.*[[:space:]].*}}DW_AT_name{{.*}}"class1"
+# CHECK: DW_TAG_variable
+# CHECK: DW_AT_name{{.*}}"var1"
+# CHECK: DW_AT_const_value
+# CHECK: DW_AT_type (0x00000000[[CLASS1:[0-9a-f]*]]
+
+# CHECK: Compile Unit:
+# CHECK: DW_TAG_compile_unit
+# CHECK: DW_AT_name{{.*}}"CU2"
+# CHECK-NOT: DW_TAG_class_type
+# CHECK-NOT: "class1"
+# CHECK: DW_TAG_variable
+# CHECK: DW_AT_name{{.*}}"var2"
+# CHECK: DW_AT_const_value
+# CHECK: DW_AT_type (0x00000000[[CLASS1]]
+
+
+
+--- !mach-o
+FileHeader:
+  magic:      0xFEEDFACF
+  cputype:    0x01000007
+  cpusubtype: 0x00000003
+  filetype:   0x00000001
+  ncmds:      2
+  sizeofcmds: 376
+  flags:      0x00002000
+  reserved:   0x00000000
+LoadCommands:
+  - cmd:      LC_SEGMENT_64
+    cmdsize:  232
+    segname:  ''
+    vmaddr:   0x00
+    vmsize:   0x300
+    fileoff:  0x300
+    filesize: 0x300
+    maxprot:  7
+    initprot: 7
+    nsects:   2
+    flags:    0
+    Sections:
+      - sectname:  __debug_abbrev
+        segname:   __DWARF
+        addr:      0x000000000000000F
+        size:      0x3c
+        offset:    0x00000380
+        align:     0
+        reloff:    0x00000000
+        nreloc:    0
+        flags:     0x02000000
+        reserved1: 0x00000000
+        reserved2: 0x00000000
+        reserved3: 0x00000000
+      - sectname:  __debug_info
+        segname:   __DWARF
+        addr:      0x000000000000100
+        size:      0x62
+        offset:    0x00000410
+        align:     0
+        reloff:    0x00000600
+        nreloc:    1
+        flags:     0x02000000
+        reserved1: 0x00000000
+        reserved2: 0x00000000
+        reserved3: 0x00000000
+        relocations:
+          - address:         0x1FC
+            symbolnum:       1
+            pcrel:           true
+            length:          3
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          0x700
+    nsyms:           2
+    stroff:          0x720
+    strsize:         10
+LinkEditData:
+  NameList:
+    - n_strx:          1
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          0
+      n_value:         0
+    - n_strx:          1
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          0
+      n_value:         0
+  StringTable:
+    - ''
+    - '__Z3foov'
+    - ''
+DWARF:
+  debug_abbrev:
+    - Table:
+      - Tag:      DW_TAG_compile_unit
+        Children: DW_CHILDREN_yes
+        Attributes:
+          - Attribute: DW_AT_producer
+            Form:      DW_FORM_string
+          - Attribute: DW_AT_language
+            Form:      DW_FORM_data2
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+      - Tag:      DW_TAG_class_type
+        Children: DW_CHILDREN_no
+        Attributes:
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+      - Tag:      DW_TAG_variable
+        Children: DW_CHILDREN_no
+        Attributes:
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+          - Attribute: DW_AT_const_value
+            Form:      DW_FORM_data4
+          - Attribute: DW_AT_type
+            Form:      DW_FORM_ref4
+    - Table:
+      - Tag:      DW_TAG_compile_unit
+        Children: DW_CHILDREN_yes
+        Attributes:
+          - Attribute: DW_AT_producer
+            Form:      DW_FORM_string
+          - Attribute: DW_AT_language
+            Form:      DW_FORM_data2
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+      - Tag:      DW_TAG_class_type
+        Children: DW_CHILDREN_no
+        Attributes:
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+      - Tag:      DW_TAG_variable
+        Children: DW_CHILDREN_no
+        Attributes:
+          - Attribute: DW_AT_name
+            Form:      DW_FORM_string
+          - Attribute: DW_AT_const_value
+            Form:      DW_FORM_data4
+          - Attribute: DW_AT_type
+            Form:      DW_FORM_ref4
+  debug_info:
+    - Version: 4
+      Entries:
+        - AbbrCode: 1
+          Values:
+            - CStr: by_hand
+            - Value:  0x04
+            - CStr: CU1
+        - AbbrCode: 2
+          Values:
+            - CStr: class1
+        - AbbrCode: 3
+          Values:
+            - CStr: var1
+            - Value:  0x00000000
+            - Value:  0x0000001a
+        - AbbrCode: 0
+    - Version: 4
+      Entries:
+        - AbbrCode: 1
+          Values:
+            - CStr: by_hand
+            - Value:  0x04
+            - CStr: CU2
+        - AbbrCode: 2
+          Values:
+            - CStr: class1
+        - AbbrCode: 3
+          Values:
+            - CStr: var2
+            - Value:  0x00000000
+            - Value:  0x0000001a
+        - AbbrCode: 0
+...