diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index 3b5ea9fa53..f2397d1b63 100644
--- a/tools/clang/include/clang-c/Index.h
+++ b/tools/clang/include/clang-c/Index.h
@@ -33,6 +33,7 @@
  */
 #define CINDEX_VERSION_MAJOR 0
 #define CINDEX_VERSION_MINOR 43
+#define CINDEX_VERSION_HAS_ISINVALIDECL_BACKPORTED
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
@@ -2616,6 +2617,16 @@ CINDEX_LINKAGE enum CXCursorKind clang_getCursorKind(CXCursor);
  */
 CINDEX_LINKAGE unsigned clang_isDeclaration(enum CXCursorKind);
 
+/**
+ * \brief Determine whether the given declaration is invalid.
+ *
+ * A declaration is invalid if it could not be parsed successfully.
+ *
+ * \returns non-zero if the cursor represents a declaration and it is
+ * invalid, otherwise NULL.
+ */
+CINDEX_LINKAGE unsigned clang_isInvalidDeclaration(CXCursor);
+
 /**
  * \brief Determine whether the given cursor kind represents a simple
  * reference.
diff --git a/test/Index/opencl-types.cl b/test/Index/opencl-types.cl
index fe0042aa20..d71893a220 100644
--- a/tools/clang/test/Index/opencl-types.cl
+++ b/tools/clang/test/Index/opencl-types.cl
@@ -16,11 +16,11 @@ void kernel testFloatTypes() {
   double4 vectorDouble;
 }
 
-// CHECK: VarDecl=scalarHalf:11:8 (Definition) [type=half] [typekind=Half] [isPOD=1]
+// CHECK: VarDecl=scalarHalf:11:8 (Definition){{( \(invalid\))?}} [type=half] [typekind=Half] [isPOD=1]
 // CHECK: VarDecl=vectorHalf:12:9 (Definition) [type=half4] [typekind=Typedef] [canonicaltype=half __attribute__((ext_vector_type(4)))] [canonicaltypekind=Unexposed] [isPOD=1]
 // CHECK: VarDecl=scalarFloat:13:9 (Definition) [type=float] [typekind=Float] [isPOD=1]
 // CHECK: VarDecl=vectorFloat:14:10 (Definition) [type=float4] [typekind=Typedef] [canonicaltype=float __attribute__((ext_vector_type(4)))] [canonicaltypekind=Unexposed] [isPOD=1]
-// CHECK: VarDecl=scalarDouble:15:10 (Definition) [type=double] [typekind=Double] [isPOD=1]
+// CHECK: VarDecl=scalarDouble:15:10 (Definition){{( \(invalid\))?}} [type=double] [typekind=Double] [isPOD=1]
 // CHECK: VarDecl=vectorDouble:16:11 (Definition) [type=double4] [typekind=Typedef] [canonicaltype=double __attribute__((ext_vector_type(4)))] [canonicaltypekind=Unexposed] [isPOD=1]
 
 #pragma OPENCL EXTENSION cl_khr_gl_msaa_sharing : enable
@@ -45,10 +45,10 @@ void kernel OCLImage3dROTest(read_only image3d_t scalarOCLImage3dRO);
 // CHECK: ParmDecl=scalarOCLImage2dArrayRO:32:61 (Definition) [type=__read_only image2d_array_t] [typekind=OCLImage2dArrayRO] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dDepthRO:33:61 (Definition) [type=__read_only image2d_depth_t] [typekind=OCLImage2dDepthRO] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dArrayDepthRO:34:72 (Definition) [type=__read_only image2d_array_depth_t] [typekind=OCLImage2dArrayDepthRO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAARO:35:59 (Definition) [type=__read_only image2d_msaa_t] [typekind=OCLImage2dMSAARO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAARO:36:70 (Definition) [type=__read_only image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAARO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAADepthRO:37:70 (Definition) [type=__read_only image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthRO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthRO:38:81 (Definition) [type=__read_only image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthRO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAARO:35:59 (Definition){{( \(invalid\))?}} [type=__read_only image2d_msaa_t] [typekind=OCLImage2dMSAARO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAARO:36:70 (Definition){{( \(invalid\))?}} [type=__read_only image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAARO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAADepthRO:37:70 (Definition){{( \(invalid\))?}} [type=__read_only image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthRO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthRO:38:81 (Definition){{( \(invalid\))?}} [type=__read_only image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthRO] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage3dRO:39:50 (Definition) [type=__read_only image3d_t] [typekind=OCLImage3dRO] [isPOD=1]
 
 void kernel OCLImage1dWOTest(write_only image1d_t scalarOCLImage1dWO);
@@ -71,11 +71,11 @@ void kernel OCLImage3dWOTest(write_only image3d_t scalarOCLImage3dWO);
 // CHECK: ParmDecl=scalarOCLImage2dArrayWO:58:62 (Definition) [type=__write_only image2d_array_t] [typekind=OCLImage2dArrayWO] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dDepthWO:59:62 (Definition) [type=__write_only image2d_depth_t] [typekind=OCLImage2dDepthWO] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dArrayDepthWO:60:73 (Definition) [type=__write_only image2d_array_depth_t] [typekind=OCLImage2dArrayDepthWO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAAWO:61:60 (Definition) [type=__write_only image2d_msaa_t] [typekind=OCLImage2dMSAAWO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAAWO:62:71 (Definition) [type=__write_only image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAAWO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAADepthWO:63:71 (Definition) [type=__write_only image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthWO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthWO:64:82 (Definition) [type=__write_only image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthWO] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage3dWO:65:51 (Definition) [type=__write_only image3d_t] [typekind=OCLImage3dWO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAAWO:61:60 (Definition){{( \(invalid\))?}} [type=__write_only image2d_msaa_t] [typekind=OCLImage2dMSAAWO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAAWO:62:71 (Definition){{( \(invalid\))?}} [type=__write_only image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAAWO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAADepthWO:63:71 (Definition){{( \(invalid\))?}} [type=__write_only image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthWO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthWO:64:82 (Definition){{( \(invalid\))?}} [type=__write_only image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthWO] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage3dWO:65:51 (Definition){{( \(invalid\))?}} [type=__write_only image3d_t] [typekind=OCLImage3dWO] [isPOD=1]
 
 void kernel OCLImage1dRWTest(read_write image1d_t scalarOCLImage1dRW);
 void kernel OCLImage1dArrayRWTest(read_write image1d_array_t scalarOCLImage1dArrayRW);
@@ -97,10 +97,10 @@ void kernel OCLImage3dRWTest(read_write image3d_t scalarOCLImage3dRW);
 // CHECK: ParmDecl=scalarOCLImage2dArrayRW:84:62 (Definition) [type=__read_write image2d_array_t] [typekind=OCLImage2dArrayRW] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dDepthRW:85:62 (Definition) [type=__read_write image2d_depth_t] [typekind=OCLImage2dDepthRW] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage2dArrayDepthRW:86:73 (Definition) [type=__read_write image2d_array_depth_t] [typekind=OCLImage2dArrayDepthRW] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAARW:87:60 (Definition) [type=__read_write image2d_msaa_t] [typekind=OCLImage2dMSAARW] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAARW:88:71 (Definition) [type=__read_write image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAARW] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dMSAADepthRW:89:71 (Definition) [type=__read_write image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthRW] [isPOD=1]
-// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthRW:90:82 (Definition) [type=__read_write image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthRW] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAARW:87:60 (Definition){{( \(invalid\))?}} [type=__read_write image2d_msaa_t] [typekind=OCLImage2dMSAARW] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAARW:88:71 (Definition){{( \(invalid\))?}} [type=__read_write image2d_array_msaa_t] [typekind=OCLImage2dArrayMSAARW] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dMSAADepthRW:89:71 (Definition){{( \(invalid\))?}} [type=__read_write image2d_msaa_depth_t] [typekind=OCLImage2dMSAADepthRW] [isPOD=1]
+// CHECK: ParmDecl=scalarOCLImage2dArrayMSAADepthRW:90:82 (Definition){{( \(invalid\))?}} [type=__read_write image2d_array_msaa_depth_t] [typekind=OCLImage2dArrayMSAADepthRW] [isPOD=1]
 // CHECK: ParmDecl=scalarOCLImage3dRW:91:51 (Definition) [type=__read_write image3d_t] [typekind=OCLImage3dRW] [isPOD=1]
 
 void kernel intPipeTestRO(read_only pipe int scalarPipe);
diff --git a/test/Index/print-type-size.cpp b/test/Index/print-type-size.cpp
index 45de93f308..1ea5346273 100644
--- a/tools/clang/test/Index/print-type-size.cpp
+++ b/tools/clang/test/Index/print-type-size.cpp
@@ -4,8 +4,8 @@
 
 namespace basic {
 
-// CHECK64: VarDecl=v:[[@LINE+2]]:6 (Definition) [type=void] [typekind=Void]
-// CHECK32: VarDecl=v:[[@LINE+1]]:6 (Definition) [type=void] [typekind=Void]
+// CHECK64: VarDecl=v:[[@LINE+2]]:6 (Definition) (invalid) [type=void] [typekind=Void]
+// CHECK32: VarDecl=v:[[@LINE+1]]:6 (Definition) (invalid) [type=void] [typekind=Void]
 void v;
 
 // CHECK64: VarDecl=v1:[[@LINE+2]]:7 (Definition) [type=void *] [typekind=Pointer] [sizeof=8] [alignof=8]
diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index cf3581e259..759ed449a4 100644
--- a/tools/clang/tools/c-index-test/c-index-test.c
+++ b/tools/clang/tools/c-index-test/c-index-test.c
@@ -810,6 +810,8 @@ static void PrintCursor(CXCursor Cursor, const char *CommentSchemaFile) {
       printf(" (variadic)");
     if (clang_Cursor_isObjCOptional(Cursor))
       printf(" (@optional)");
+    if (clang_isInvalidDeclaration(Cursor))
+      printf(" (invalid)");
 
     switch (clang_getCursorExceptionSpecificationType(Cursor))
     {
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 9ba4d5bf30..584de42e7c 100644
--- a/tools/clang/tools/libclang/CIndex.cpp
+++ b/tools/clang/tools/libclang/CIndex.cpp
@@ -5346,6 +5346,15 @@ unsigned clang_isDeclaration(enum CXCursorKind K) {
          (K >= CXCursor_FirstExtraDecl && K <= CXCursor_LastExtraDecl);
 }
 
+unsigned clang_isInvalidDeclaration(CXCursor C) {
+  if (clang_isDeclaration(C.kind)) {
+    if (const Decl *D = getCursorDecl(C))
+      return D->isInvalidDecl();
+  }
+
+  return 0;
+}
+
 unsigned clang_isReference(enum CXCursorKind K) {
   return K >= CXCursor_FirstRef && K <= CXCursor_LastRef;
 }
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index e0d178a529..7192baab6a 100644
--- a/tools/clang/tools/libclang/libclang.exports
+++ b/tools/clang/tools/libclang/libclang.exports
@@ -286,6 +286,7 @@ clang_isAttribute
 clang_isConstQualifiedType
 clang_isCursorDefinition
 clang_isDeclaration
+clang_isInvalidDeclaration
 clang_isExpression
 clang_isFileMultipleIncludeGuarded
 clang_isFunctionTypeVariadic