1 files changed, 24 insertions, 0 deletions
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index e67ffdbf119..9946f82405e 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -73,6 +73,30 @@ void defineCPUMacros(MacroBuilder &Builder, StringRef CPUName, bool Tuning) {
     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__");