After rebase, some more paches needed.

Author: tinysun212

cmake/modules/AddSwift.cmake

@@ -932,6 +932,10 @@ function(_add_swift_library_single target name)
     set_target_properties("${target}"
       PROPERTIES
       INSTALL_RPATH "$ORIGIN:/usr/lib/swift/linux")
+  elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Cygwin")
+    set_target_properties("${target}"
+      PROPERTIES
+      INSTALL_RPATH "$ORIGIN:/usr/lib/swift/windows")
   endif()
 
   set_target_properties("${target}" PROPERTIES BUILD_WITH_INSTALL_RPATH YES)

lib/IDE/ReconstructType.cpp

@@ -54,6 +54,8 @@
 
 #include "swift/IDE/Utils.h"
 
+#include <cstdio>
+
 typedef const std::string ConstString;
 typedef void Log;
 typedef swift::ASTContext SwiftASTContext;

lib/IRGen/GenDecl.cpp

@@ -2048,6 +2048,9 @@ llvm::Constant *IRGenModule::emitTypeMetadataRecords() {
   case llvm::Triple::ELF:
     sectionName = ".swift2_type_metadata";
     break;
+  case llvm::Triple::COFF:
+    sectionName = ".sw2tymd";
+    break;
   default:
     llvm_unreachable("Don't know how to emit type metadata table for "
                      "the selected object format.");

stdlib/public/core/Builtin.swift

@@ -326,10 +326,33 @@ internal func _usesNativeSwiftReferenceCounting(theClass: AnyClass) -> Bool {
 #endif
 }
 
+#if os(Windows)
+// If the return type of a C/C++ function is a structure,
+// the calling convension is different from caller's.  
+// A wrapper function is introduced.
+struct PrivPair {
+  var negative : UInt
+  var positive : UInt
+}
+
+@_silgen_name("swift_class_getInstanceExtents")
+private func swift_class_getInstanceExtents_raw(inout pair: PrivPair,
+                                                theClass: AnyClass)
+
+@warn_unused_result
+func swift_class_getInstanceExtents(theClass: AnyClass)
+  -> (negative: UInt, positive: UInt) {
+  var pair = PrivPair(negative : 0, positive : 0)
+  swift_class_getInstanceExtents_raw(&pair, theClass: theClass)
+
+  return (pair.negative, pair.positive)
+}
+#else
 @warn_unused_result
 @_silgen_name("swift_class_getInstanceExtents")
 func swift_class_getInstanceExtents(theClass: AnyClass)
   -> (negative: UInt, positive: UInt)
+#endif
 
 @warn_unused_result
 @_silgen_name("swift_objc_class_unknownGetInstanceExtents")

stdlib/public/runtime/MetadataLookup.cpp

@@ -49,6 +49,8 @@ using namespace Demangle;
 #define SWIFT_TYPE_METADATA_SECTION "__swift2_types"
 #elif defined(__ELF__)
 #define SWIFT_TYPE_METADATA_SECTION ".swift2_type_metadata_start"
+#elif defined(__CYGWIN__)
+#define SWIFT_TYPE_METADATA_SECTION ".sw2tymd"
 #endif
 
 // Type Metadata Cache.
@@ -176,6 +178,31 @@ static int _addImageTypeMetadataRecords(struct dl_phdr_info *info,
   dlclose(handle);
   return 0;
 }
+#elif defined(__CYGWIN__)
+static int _addImageTypeMetadataRecords(struct dl_phdr_info *info,
+                                        size_t size, void * /*data*/) {
+  void *handle;
+  if (!info->dlpi_name || info->dlpi_name[0] == '\0') {
+    handle = dlopen(nullptr, RTLD_LAZY);
+  } else
+    handle = dlopen(info->dlpi_name, RTLD_LAZY | RTLD_NOLOAD);
+
+  unsigned long recordsSize;
+  const uint8_t *records =
+    _swift_getSectionDataPE(handle, SWIFT_TYPE_METADATA_SECTION,
+                           &recordsSize);
+
+  if (!records) {
+    // if there are no type metadata records, don't hold this handle open.
+    dlclose(handle);
+    return 0;
+  }
+
+  _addImageTypeMetadataRecordsBlock(records, recordsSize);
+
+  dlclose(handle);
+  return 0;
+}
 #endif
 
 static void _initializeCallbacksToInspectDylib() {
@@ -190,6 +217,8 @@ static void _initializeCallbacksToInspectDylib() {
   // FIXME: Find a way to have this continue to happen after.
   // rdar://problem/19045112
   dl_iterate_phdr(_addImageTypeMetadataRecords, nullptr);
+#elif defined(__CYGWIN__)
+  _swift_dl_iterate_phdr(_addImageTypeMetadataRecords, nullptr);
 #else
 # error No known mechanism to inspect dynamic libraries on this platform.
 #endif

utils/swift_build_support/swift_build_support/targets.py

@@ -40,4 +40,8 @@ def host_target():
         if machine == 'amd64':
             return 'freebsd-x86_64'
 
+    elif system == 'CYGWIN_NT-10.0':
+        if machine == 'x86_64':
+            return 'cygwin-x86_64'
+
     return None