[RemoteMirror] Add a call to the interop header to set the upcoming classIsSwiftMask value.

Author: mikeash

include/swift/SwiftRemoteMirror/SwiftRemoteMirrorLegacyInterop.h

@@ -55,6 +55,13 @@ static inline void
 swift_reflection_interop_destroyReflectionContext(
   SwiftReflectionInteropContextRef ContextRef);
 
+/// Set the is-Swift mask for the stable ABI on the current system.
+/// NOTE: must be called after interop_addLibrary is used to add the
+/// stable ABI remote mirror library in order to take effect.
+static inline void
+swift_reflection_interop_setClassIsSwiftMask(
+  SwiftReflectionInteropContextRef ContextRef, uint64_t mask);
+
 static inline int
 swift_reflection_interop_addImage(SwiftReflectionInteropContextRef ContextRef,
                                   swift_addr_t imageStart);
@@ -175,6 +182,8 @@ typedef int (*ReadBytesFunctionLegacy)(void *reader_context, swift_addr_t addres
                                        void *dest, uint64_t size);
 
 struct SwiftReflectionFunctions {
+  unsigned long long *classIsSwiftMaskPtr;
+
   uint16_t (*getSupportedMetadataVersion)(void);
 
   SwiftReflectionContextRef (*createReflectionContext)(
@@ -406,6 +415,8 @@ swift_reflection_interop_loadFunctions(struct SwiftReflectionInteropContext *Con
   } while (0)
 #define LOAD(name) LOAD_NAMED(name, "swift_reflection_" #name)
 
+  Functions->classIsSwiftMaskPtr =
+    (unsigned long long *)dlsym(Handle, "swift_reflection_classIsSwiftMask");
   LOAD(getSupportedMetadataVersion);
   uint16_t version = Functions->getSupportedMetadataVersion();
   if (version < SWIFT_LEGACY_METADATA_MIN_VERSION)
@@ -575,6 +586,15 @@ swift_reflection_interop_destroyReflectionContext(
   free(ContextRef);
 }
 
+static inline void
+swift_reflection_interop_setClassIsSwiftMask(
+  SwiftReflectionInteropContextRef ContextRef, uint64_t mask) {
+  FOREACH_LIBRARY {
+    if (Library->Functions.classIsSwiftMaskPtr)
+      *Library->Functions.classIsSwiftMaskPtr = mask;
+  }
+}
+
 #ifndef __LP64__
 typedef const struct mach_header MachHeader;
 #else

unittests/Reflection/RemoteMirrorInterop/test.m

@@ -96,6 +96,19 @@ int main(int argc, char **argv) {
       fprintf(stderr, "Failed to add library at %s\n", argv[i]);
       exit(1);
     }
+    
+    unsigned long long *isSwiftMaskPtr = dlsym(
+      Handle, "swift_reflection_classIsSwiftMask");
+    if (isSwiftMaskPtr) {
+      printf("%s has isSwiftMask. Original value is %lld\n",
+             argv[i], *isSwiftMaskPtr);
+      swift_reflection_interop_setClassIsSwiftMask(Context, 1);
+      printf("Set mask to 1, value is now %lld\n", *isSwiftMaskPtr);
+      swift_reflection_interop_setClassIsSwiftMask(Context, 2);
+      printf("Set mask to 2, value is now %lld\n", *isSwiftMaskPtr);
+    } else {
+      printf("%s does not have isSwiftMask\n", argv[i]);
+    }
   }
 
   int hasLegacy = 0;

unittests/Reflection/RemoteMirrorInterop/test.py

@@ -21,9 +21,10 @@
 
 absoluteArgs = [os.path.abspath(arg) for arg in args]
 swiftcs = [os.path.join(arg, 'bin', 'swiftc') for arg in absoluteArgs]
-mirrorlibs = [os.path.join(arg, 'lib', 'swift', 'macosx',
-                           'libswiftRemoteMirror.dylib')
-              for arg in absoluteArgs]
+swiftlibs = [os.path.join(arg, 'lib', 'swift', 'macosx')
+             for arg in absoluteArgs]
+mirrorlibs = [os.path.join(lib, 'libswiftRemoteMirror.dylib')
+              for lib in swiftlibs]
 
 os.chdir(os.path.dirname(sys.argv[0]))
 
@@ -37,10 +38,11 @@
                        '-g', 'test.m'])
 
 # Build a test library with each Swift compiler passed in.
-for i, swiftc in enumerate(swiftcs):
+for i, (swiftc, swiftlib) in enumerate(zip(swiftcs, swiftlibs)):
     subprocess.check_call(
         ['xcrun', swiftc, '-emit-library', 'test.swift',
-         '-o', os.path.join('/tmp', 'libtest' + str(i) + '.dylib')])
+         '-o', os.path.join('/tmp', 'libtest' + str(i) + '.dylib'),
+         '-Xlinker', '-rpath', '-Xlinker', swiftlib])
 
 # Run the test harness with all combinations of the remote mirror libraries.
 for i in range(len(swiftcs) + 1):