Index: lib/Basic/Targets.h
===================================================================
--- lib/Basic/Targets.h
+++ lib/Basic/Targets.h
@@ -42,6 +42,10 @@
 LLVM_LIBRARY_VISIBILITY
 void addMinGWDefines(const clang::LangOptions &Opts,
                      clang::MacroBuilder &Builder);
+
+LLVM_LIBRARY_VISIBILITY
+void addCygMingDefines(const clang::LangOptions &Opts,
+                       clang::MacroBuilder &Builder);
 } // namespace targets
 } // namespace clang
 #endif // LLVM_CLANG_LIB_BASIC_TARGETS_H
Index: lib/Basic/Targets.cpp
===================================================================
--- lib/Basic/Targets.cpp
+++ lib/Basic/Targets.cpp
@@ -73,6 +73,30 @@
     Builder.defineMacro("__tune_" + CPUName + "__");
 }
 
+void addCygMingDefines(const LangOptions &Opts, MacroBuilder &Builder) {
+  // Mingw and cygwin define __declspec(a) to __attribute__((a)).  Clang
+  // supports __declspec natively under -fms-extensions, but we define a no-op
+  // __declspec macro anyway for pre-processor compatibility.
+  if (Opts.MicrosoftExt)
+    Builder.defineMacro("__declspec", "__declspec");
+  else
+    Builder.defineMacro("__declspec(a)", "__attribute__((a))");
+
+  if (!Opts.MicrosoftExt) {
+    // Provide macros for all the calling convention keywords.  Provide both
+    // single and double underscore prefixed variants.  These are available on
+    // x64 as well as x86, even though they have no effect.
+    const char *CCs[] = {"cdecl", "stdcall", "fastcall", "thiscall", "pascal"};
+    for (const char *CC : CCs) {
+      std::string GCCSpelling = "__attribute__((__";
+      GCCSpelling += CC;
+      GCCSpelling += "__))";
+      Builder.defineMacro(Twine("_") + CC, GCCSpelling);
+      Builder.defineMacro(Twine("__") + CC, GCCSpelling);
+    }
+  }
+}
+
 void addMinGWDefines(const LangOptions &Opts, MacroBuilder &Builder) {
   Builder.defineMacro("__MSVCRT__");
   Builder.defineMacro("__MINGW32__");
Index: lib/Basic/Targets/X86.h
===================================================================
--- lib/Basic/Targets/X86.h
+++ lib/Basic/Targets/X86.h
@@ -691,30 +691,6 @@
   }
 };
 
-static void addCygMingDefines(const LangOptions &Opts, MacroBuilder &Builder) {
-  // Mingw and cygwin define __declspec(a) to __attribute__((a)).  Clang
-  // supports __declspec natively under -fms-extensions, but we define a no-op
-  // __declspec macro anyway for pre-processor compatibility.
-  if (Opts.MicrosoftExt)
-    Builder.defineMacro("__declspec", "__declspec");
-  else
-    Builder.defineMacro("__declspec(a)", "__attribute__((a))");
-
-  if (!Opts.MicrosoftExt) {
-    // Provide macros for all the calling convention keywords.  Provide both
-    // single and double underscore prefixed variants.  These are available on
-    // x64 as well as x86, even though they have no effect.
-    const char *CCs[] = {"cdecl", "stdcall", "fastcall", "thiscall", "pascal"};
-    for (const char *CC : CCs) {
-      std::string GCCSpelling = "__attribute__((__";
-      GCCSpelling += CC;
-      GCCSpelling += "__))";
-      Builder.defineMacro(Twine("_") + CC, GCCSpelling);
-      Builder.defineMacro(Twine("__") + CC, GCCSpelling);
-    }
-  }
-}
-
 // x86-32 MinGW target
 class LLVM_LIBRARY_VISIBILITY MinGWX86_32TargetInfo
     : public WindowsX86_32TargetInfo {