diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -211,6 +211,7 @@
   uint32_t functionPadMin = 0;
   bool dynamicBase = true;
   bool allowBind = true;
+  bool cetCompat = false;
   bool nxCompat = true;
   bool allowIsolation = true;
   bool terminalServerAware = true;
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1549,6 +1549,7 @@
                        !args.hasArg(OPT_profile));
   config->integrityCheck =
       args.hasFlag(OPT_integritycheck, OPT_integritycheck_no, false);
+  config->cetCompat = args.hasFlag(OPT_cetcompat, OPT_cetcompat_no, false);
   config->nxCompat = args.hasFlag(OPT_nxcompat, OPT_nxcompat_no, true);
   for (auto *arg : args.filtered(OPT_swaprun))
     parseSwaprun(arg->getValue());
diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -148,6 +148,8 @@
 defm appcontainer : B<"appcontainer",
                       "Image can only be run in an app container",
                       "Image can run outside an app container (default)">;
+defm cetcompat : B<"cetcompat", "Mark executable image as compatible with Control-flow Enforcement Technology (CET) Shadow Stack",
+                  "Don't mark executable image as compatible with Control-flow Enforcement Technology (CET) Shadow Stack (default)">;
 defm dynamicbase : B<"dynamicbase", "Enable ASLR (default unless /fixed)",
                      "Disable ASLR (default when /fixed)">;
 defm fixed : B<"fixed", "Disable base relocations",
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -91,7 +91,7 @@
 
 class DebugDirectoryChunk : public NonSectionChunk {
 public:
-  DebugDirectoryChunk(const std::vector<Chunk *> &r, bool writeRepro)
+  DebugDirectoryChunk(const std::vector<std::pair<COFF::DebugType, Chunk *>> &r, bool writeRepro)
       : records(r), writeRepro(writeRepro) {}
 
   size_t getSize() const override {
@@ -101,11 +101,12 @@
   void writeTo(uint8_t *b) const override {
     auto *d = reinterpret_cast<debug_directory *>(b);
 
-    for (const Chunk *record : records) {
-      OutputSection *os = record->getOutputSection();
-      uint64_t offs = os->getFileOff() + (record->getRVA() - os->getRVA());
-      fillEntry(d, COFF::IMAGE_DEBUG_TYPE_CODEVIEW, record->getSize(),
-                record->getRVA(), offs);
+    for (const std::pair<COFF::DebugType, Chunk *> record : records) {
+      Chunk *c = record.second;
+      OutputSection *os = c->getOutputSection();
+      uint64_t offs = os->getFileOff() + (c->getRVA() - os->getRVA());
+      fillEntry(d, record.first, c->getSize(),
+                c->getRVA(), offs);
       ++d;
     }
 
@@ -140,7 +141,7 @@
   }
 
   mutable std::vector<support::ulittle32_t *> timeDateStamps;
-  const std::vector<Chunk *> &records;
+  const std::vector<std::pair<COFF::DebugType, Chunk *>> &records;
   bool writeRepro;
 };
 
@@ -165,6 +166,22 @@
   mutable codeview::DebugInfo *buildId = nullptr;
 };
 
+class ExtendedDllCharacteristicsChunk : public NonSectionChunk {
+public:
+  ExtendedDllCharacteristicsChunk(uint32_t c)
+      : characteristics(c) {}
+
+  size_t getSize() const override {
+    return 4;
+  }
+
+  void writeTo(uint8_t *buf) const override {
+    write32le(buf, characteristics);
+  }
+
+  uint32_t characteristics = 0;
+};
+
 // PartialSection represents a group of chunks that contribute to an
 // OutputSection. Collating a collection of PartialSections of same name and
 // characteristics constitutes the OutputSection.
@@ -250,7 +267,7 @@
   bool setNoSEHCharacteristic = false;
 
   DebugDirectoryChunk *debugDirectory = nullptr;
-  std::vector<Chunk *> debugRecords;
+  std::vector<std::pair<COFF::DebugType, Chunk *>> debugRecords;
   CVDebugRecordChunk *buildId = nullptr;
   ArrayRef<uint8_t> sectionTable;
 
@@ -920,8 +937,9 @@
 
   // Create Debug Information Chunks
   OutputSection *debugInfoSec = config->mingw ? buildidSec : rdataSec;
-  if (config->debug || config->repro) {
+  if (config->debug || config->repro || config->cetCompat) {
     debugDirectory = make<DebugDirectoryChunk>(debugRecords, config->repro);
+    debugDirectory->setAlignment(4);
     debugInfoSec->addChunk(debugDirectory);
   }
 
@@ -931,10 +949,18 @@
     // allowing a debugger to match a PDB and an executable.  So we need it even
     // if we're ultimately not going to write CodeView data to the PDB.
     buildId = make<CVDebugRecordChunk>();
-    debugRecords.push_back(buildId);
+    debugRecords.push_back({COFF::IMAGE_DEBUG_TYPE_CODEVIEW, buildId});
+  }
+
+  if (config->cetCompat) {
+    ExtendedDllCharacteristicsChunk *extendedDllChars =
+      make<ExtendedDllCharacteristicsChunk>(IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT);
+    debugRecords.push_back({COFF::IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS, extendedDllChars});
+  }
 
-    for (Chunk *c : debugRecords)
-      debugInfoSec->addChunk(c);
+  if (debugRecords.size() > 0) {
+    for (std::pair<COFF::DebugType, Chunk *> r : debugRecords)
+      debugInfoSec->addChunk(r.second);
   }
 
   // Create SEH table. x86-only.
diff --git a/lld/test/COFF/options.test b/lld/test/COFF/options.test
--- a/lld/test/COFF/options.test
+++ b/lld/test/COFF/options.test
@@ -50,6 +50,16 @@
 # RUN: llvm-readobj --file-headers %t.exe | FileCheck -check-prefix=NONXCOMPAT %s
 NONXCOMPAT-NOT: IMAGE_DLL_CHARACTERISTICS_NX_COMPAT
 
+# RUN: lld-link /out:%t.exe /entry:main /cetcompat %t.obj
+# RUN: llvm-readobj --coff-debug-directory %t.exe | FileCheck -check-prefix=CETCOMPAT %s
+CETCOMPAT: IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT
+
+# RUN: lld-link /out:%t.exe /entry:main %t.obj
+# RUN: llvm-readobj --coff-debug-directory %t.exe | FileCheck -check-prefix=NONCETCOMPAT %s
+# RUN: lld-link /out:%t.exe /entry:main /cetcompat:no %t.obj
+# RUN: llvm-readobj --coff-debug-directory %t.exe | FileCheck -check-prefix=NONCETCOMPAT %s
+NONCETCOMPAT-NOT: IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT
+
 # RUN: lld-link /out:%t.exe /entry:main /swaprun:CD %t.obj
 # RUN: llvm-readobj --file-headers %t.exe | FileCheck -check-prefix=SWAPCD %s
 # RUN: lld-link /out:%t.exe /entry:main /swaprun:cd,net %t.obj
diff --git a/llvm/include/llvm/BinaryFormat/COFF.h b/llvm/include/llvm/BinaryFormat/COFF.h
--- a/llvm/include/llvm/BinaryFormat/COFF.h
+++ b/llvm/include/llvm/BinaryFormat/COFF.h
@@ -642,6 +642,11 @@
   IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE = 0x8000
 };
 
+enum ExtendedDLLCharacteristics : unsigned {
+  /// Image is CET compatible
+  IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT = 0x0001
+};
+
 enum DebugType : unsigned {
   IMAGE_DEBUG_TYPE_UNKNOWN = 0,
   IMAGE_DEBUG_TYPE_COFF = 1,
@@ -660,6 +665,7 @@
   IMAGE_DEBUG_TYPE_ILTCG = 14,
   IMAGE_DEBUG_TYPE_MPX = 15,
   IMAGE_DEBUG_TYPE_REPRO = 16,
+  IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS = 20,
 };
 
 enum BaseRelocationType : unsigned {
diff --git a/llvm/test/tools/llvm-readobj/COFF/Inputs/has_cet.exe b/llvm/test/tools/llvm-readobj/COFF/Inputs/has_cet.exe
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/llvm/test/tools/llvm-readobj/COFF/cetcompat.test b/llvm/test/tools/llvm-readobj/COFF/cetcompat.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/COFF/cetcompat.test
@@ -0,0 +1,19 @@
+RUN: llvm-readobj --coff-debug-directory %p/Inputs/has_cet.exe | FileCheck %s
+
+CHECK:  DebugEntry {
+CHECK:    Characteristics: 0x0
+CHECK:    TimeDateStamp: 2019-06-20 20:45:09 (0x5D0BF055)
+CHECK:    MajorVersion: 0x0
+CHECK:    MinorVersion: 0x0
+CHECK:    Type: ExtendedDLLCharacteristics (0x14)
+CHECK:    SizeOfData: 0x4
+CHECK:    AddressOfRawData: 0x146A8
+CHECK:    PointerToRawData: 0x138A8
+CHECK:    ExtendedCharacteristics [ (0x1)
+CHECK:      IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT (0x1)
+CHECK:    ]
+CHECK:    RawData (
+CHECK:      0000: 01000000                             |....|
+CHECK:    )
+CHECK:  }
+
diff --git a/llvm/tools/llvm-readobj/COFFDumper.cpp b/llvm/tools/llvm-readobj/COFFDumper.cpp
--- a/llvm/tools/llvm-readobj/COFFDumper.cpp
+++ b/llvm/tools/llvm-readobj/COFFDumper.cpp
@@ -409,6 +409,10 @@
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE),
 };
 
+static const EnumEntry<COFF::ExtendedDLLCharacteristics> PEExtendedDLLCharacteristics[] = {
+  LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_DLL_CHARACTERISTICS_EX_CET_COMPAT),
+};
+
 static const EnumEntry<COFF::SectionCharacteristics>
 ImageSectionCharacteristics[] = {
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_SCN_TYPE_NOLOAD           ),
@@ -516,23 +520,24 @@
 };
 
 static const EnumEntry<COFF::DebugType> ImageDebugType[] = {
-  { "Unknown"    , COFF::IMAGE_DEBUG_TYPE_UNKNOWN       },
-  { "COFF"       , COFF::IMAGE_DEBUG_TYPE_COFF          },
-  { "CodeView"   , COFF::IMAGE_DEBUG_TYPE_CODEVIEW      },
-  { "FPO"        , COFF::IMAGE_DEBUG_TYPE_FPO           },
-  { "Misc"       , COFF::IMAGE_DEBUG_TYPE_MISC          },
-  { "Exception"  , COFF::IMAGE_DEBUG_TYPE_EXCEPTION     },
-  { "Fixup"      , COFF::IMAGE_DEBUG_TYPE_FIXUP         },
-  { "OmapToSrc"  , COFF::IMAGE_DEBUG_TYPE_OMAP_TO_SRC   },
-  { "OmapFromSrc", COFF::IMAGE_DEBUG_TYPE_OMAP_FROM_SRC },
-  { "Borland"    , COFF::IMAGE_DEBUG_TYPE_BORLAND       },
-  { "Reserved10" , COFF::IMAGE_DEBUG_TYPE_RESERVED10    },
-  { "CLSID"      , COFF::IMAGE_DEBUG_TYPE_CLSID         },
-  { "VCFeature"  , COFF::IMAGE_DEBUG_TYPE_VC_FEATURE    },
-  { "POGO"       , COFF::IMAGE_DEBUG_TYPE_POGO          },
-  { "ILTCG"      , COFF::IMAGE_DEBUG_TYPE_ILTCG         },
-  { "MPX"        , COFF::IMAGE_DEBUG_TYPE_MPX           },
-  { "Repro"      , COFF::IMAGE_DEBUG_TYPE_REPRO         },
+  { "Unknown"             , COFF::IMAGE_DEBUG_TYPE_UNKNOWN                     },
+  { "COFF"                , COFF::IMAGE_DEBUG_TYPE_COFF                        },
+  { "CodeView"            , COFF::IMAGE_DEBUG_TYPE_CODEVIEW                    },
+  { "FPO"                 , COFF::IMAGE_DEBUG_TYPE_FPO                         },
+  { "Misc"                , COFF::IMAGE_DEBUG_TYPE_MISC                        },
+  { "Exception"           , COFF::IMAGE_DEBUG_TYPE_EXCEPTION                   },
+  { "Fixup"               , COFF::IMAGE_DEBUG_TYPE_FIXUP                       },
+  { "OmapToSrc"           , COFF::IMAGE_DEBUG_TYPE_OMAP_TO_SRC                 },
+  { "OmapFromSrc"         , COFF::IMAGE_DEBUG_TYPE_OMAP_FROM_SRC               },
+  { "Borland"             , COFF::IMAGE_DEBUG_TYPE_BORLAND                     },
+  { "Reserved10"          , COFF::IMAGE_DEBUG_TYPE_RESERVED10                  },
+  { "CLSID"               , COFF::IMAGE_DEBUG_TYPE_CLSID                       },
+  { "VCFeature"           , COFF::IMAGE_DEBUG_TYPE_VC_FEATURE                  },
+  { "POGO"                , COFF::IMAGE_DEBUG_TYPE_POGO                        },
+  { "ILTCG"               , COFF::IMAGE_DEBUG_TYPE_ILTCG                       },
+  { "MPX"                 , COFF::IMAGE_DEBUG_TYPE_MPX                         },
+  { "Repro"               , COFF::IMAGE_DEBUG_TYPE_REPRO                       },
+  { "ExtendedDLLCharacteristics", COFF::IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS },
 };
 
 static const EnumEntry<COFF::WeakExternalCharacteristics>
@@ -736,12 +741,19 @@
         W.printString("PDBFileName", PDBFileName);
       }
     } else if (D.SizeOfData != 0) {
-      // FIXME: Type values of 12 and 13 are commonly observed but are not in
-      // the documented type enum.  Figure out what they mean.
+      // FIXME: Data visualization for IMAGE_DEBUG_TYPE_VC_FEATURE and
+      // IMAGE_DEBUG_TYPE_POGO?
       ArrayRef<uint8_t> RawData;
       if (std::error_code EC = Obj->getRvaAndSizeAsBytes(D.AddressOfRawData,
                                                          D.SizeOfData, RawData))
         reportError(errorCodeToError(EC), Obj->getFileName());
+      if (D.Type == COFF::IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS) {
+        // FIXME right now the only possible value would fit in 8 bits,
+        // but that might change in the future
+        uint16_t Characteristics = RawData[0];
+        W.printFlags ("ExtendedCharacteristics", Characteristics,
+                      makeArrayRef(PEExtendedDLLCharacteristics));
+      }
       W.printBinaryBlock("RawData", RawData);
     }
   }