[RemoteMirror] Update interop to handle 4.2 libraries.

The Remote Mirror interop header now accepts an arbitrary number of remote mirror libraries so that it can have 4.1, 4.2, and 5.0 loaded side by side.

rdar://problem/45808282

Author: mikeash

include/swift/SwiftRemoteMirror/SwiftRemoteMirrorLegacyInterop.h

@@ -37,14 +37,19 @@
 static inline SwiftReflectionInteropContextRef
 swift_reflection_interop_createReflectionContext(
     void *ReaderContext,
-    void *LibraryHandle,
-    void *LegacyLibraryHandle,
     uint8_t PointerSize,
     FreeBytesFunction FreeBytes,
     ReadBytesFunction ReadBytes,
     GetStringLengthFunction GetStringLength,
     GetSymbolAddressFunction GetSymbolAddress);
 
+/// Add a library handle to the interop context. Returns 1 if the
+/// library was added successfully, 0 if a symbol couldn't be looked up
+/// or the reported metadata version is too old.
+static inline int
+swift_reflection_interop_addLibrary(
+  SwiftReflectionInteropContextRef ContextRef, void *LibraryHandle);
+
 static inline void
 swift_reflection_interop_destroyReflectionContext(
   SwiftReflectionInteropContextRef ContextRef);
@@ -283,6 +288,7 @@ struct SwiftReflectionInteropContextLegacyImageRangeList {
 
 struct SwiftReflectionInteropContext {
   void *ReaderContext;
+  uint8_t PointerSize;
   FreeBytesFunction FreeBytes;
   ReadBytesFunction ReadBytes;
   uint64_t (*GetStringLength)(void *reader_context,
@@ -291,8 +297,7 @@ struct SwiftReflectionInteropContext {
                                    const char *name,
                                    uint64_t name_length);
 
-  // Currently we support at most two libraries.
-  struct SwiftReflectionInteropContextLibrary Libraries[2];
+  struct SwiftReflectionInteropContextLibrary *Libraries;
   int LibraryCount;
 
   struct SwiftReflectionInteropContextFreeList *FreeList;
@@ -381,12 +386,11 @@ swift_reflection_interop_libraryForObject(
   return swift_reflection_interop_libraryForAddress(ContextRef, Metadata);
 }
 
-static inline void
+static inline int
 swift_reflection_interop_loadFunctions(struct SwiftReflectionInteropContext *Context,
-                                       void *Handle,
-                                       int IsLegacy) {
+                                       void *Handle) {
   if (Handle == NULL)
-    return;
+    return 0;
 
   struct SwiftReflectionInteropContextLibrary *Library = &Context
     ->Libraries[Context->LibraryCount];
@@ -397,14 +401,16 @@ swift_reflection_interop_loadFunctions(struct SwiftReflectionInteropContext *Con
 #endif
 #define LOAD_NAMED(field, symbol) do { \
     Functions->field = (decltype(Functions->field))dlsym(Handle, symbol); \
-    if (Functions->field == NULL) return; \
+    if (Functions->field == NULL) return 0; \
   } while (0)
 #define LOAD(name) LOAD_NAMED(name, "swift_reflection_" #name)
 
   LOAD(getSupportedMetadataVersion);
   uint16_t version = Functions->getSupportedMetadataVersion();
   if (version < SWIFT_LEGACY_METADATA_MIN_VERSION)
-    return;
+    return 0;
+  
+  int IsLegacy = dlsym(Handle, "swift_reflection_addImage") == NULL;
 
   if (IsLegacy) {
     LOAD_NAMED(createReflectionContextLegacy, "swift_reflection_createReflectionContext");
@@ -438,7 +444,7 @@ swift_reflection_interop_loadFunctions(struct SwiftReflectionInteropContext *Con
   Library->IsLegacy = IsLegacy;
   Context->LibraryCount++;
 
-  return;
+  return 1;
 
 #undef LOAD
 #undef LOAD_NAMED
@@ -470,6 +476,7 @@ swift_reflection_interop_readBytesAdapter(void *reader_context,
 static inline uint8_t
 swift_reflection_interop_getSizeAdapter(void *reader_context) {
   // Legacy library doesn't pay attention to these anyway.
+  (void)reader_context;
   return sizeof(void *);
 }
 
@@ -492,8 +499,6 @@ swift_reflection_interop_GetSymbolAddressAdapter(
 static inline SwiftReflectionInteropContextRef
 swift_reflection_interop_createReflectionContext(
     void *ReaderContext,
-    void *LibraryHandle,
-    void *LegacyLibraryHandle,
     uint8_t PointerSize,
     FreeBytesFunction FreeBytes,
     ReadBytesFunction ReadBytes,
@@ -503,15 +508,27 @@ swift_reflection_interop_createReflectionContext(
   SwiftReflectionInteropContextRef ContextRef =
     (SwiftReflectionInteropContextRef)calloc(sizeof(*ContextRef), 1);
 
-  swift_reflection_interop_loadFunctions(ContextRef, LibraryHandle, 0);
-  swift_reflection_interop_loadFunctions(ContextRef, LegacyLibraryHandle, 1);
+  ContextRef->ReaderContext = ReaderContext;
+  ContextRef->PointerSize = PointerSize;
+  ContextRef->FreeBytes = FreeBytes;
+  ContextRef->ReadBytes = ReadBytes;
+  ContextRef->GetStringLength = GetStringLength;
+  ContextRef->GetSymbolAddress = GetSymbolAddress;
 
-  if (ContextRef->LibraryCount == 0) {
-    free(ContextRef);
-    return NULL;
-  }
+  ContextRef->AddressToLibraryCache = CFDictionaryCreateMutable(NULL, 0, NULL, NULL);
 
-  FOREACH_LIBRARY {
+  return ContextRef;
+}
+
+static inline int
+swift_reflection_interop_addLibrary(
+  SwiftReflectionInteropContextRef ContextRef, void *LibraryHandle) {
+  size_t NewSize = (ContextRef->LibraryCount + 1) * sizeof(*ContextRef->Libraries);
+  ContextRef->Libraries = realloc(ContextRef->Libraries, NewSize);
+  int Success = swift_reflection_interop_loadFunctions(ContextRef, LibraryHandle);
+  if (Success) {
+    struct SwiftReflectionInteropContextLibrary *Library =
+      &ContextRef->Libraries[ContextRef->LibraryCount - 1];
     if (Library->IsLegacy) {
       Library->Context = Library->Functions.createReflectionContextLegacy(
         ContextRef,
@@ -520,20 +537,12 @@ swift_reflection_interop_createReflectionContext(
         swift_reflection_interop_GetStringLengthAdapter,
         swift_reflection_interop_GetSymbolAddressAdapter);
     } else {
-      Library->Context = Library->Functions.createReflectionContext(ReaderContext,
-      PointerSize, FreeBytes, ReadBytes, GetStringLength, GetSymbolAddress);
+      Library->Context = Library->Functions.createReflectionContext(
+        ContextRef->ReaderContext,
+      ContextRef->PointerSize, ContextRef->FreeBytes, ContextRef->ReadBytes, ContextRef->GetStringLength, ContextRef->GetSymbolAddress);
     }
   }
-  
-  ContextRef->ReaderContext = ReaderContext;
-  ContextRef->FreeBytes = FreeBytes;
-  ContextRef->ReadBytes = ReadBytes;
-  ContextRef->GetStringLength = GetStringLength;
-  ContextRef->GetSymbolAddress = GetSymbolAddress;
-  
-  ContextRef->AddressToLibraryCache = CFDictionaryCreateMutable(NULL, 0, NULL, NULL);
-  
-  return ContextRef;
+  return Success;
 }
 
 static inline void
@@ -542,6 +551,7 @@ swift_reflection_interop_destroyReflectionContext(
   FOREACH_LIBRARY {
     Library->Functions.destroyReflectionContext(Library->Context);
   }
+  free(ContextRef->Libraries);
   struct SwiftReflectionInteropContextLegacyImageRangeList *LegacyImageRangeList
     = ContextRef->LegacyImageRangeList;
   while (LegacyImageRangeList != NULL) {

unittests/Reflection/RemoteMirrorInterop/test.m

@@ -57,34 +57,28 @@ uint64_t GetStringLength(void *context, swift_addr_t address) {
 }
 
 swift_addr_t GetSymbolAddress(void *context, const char *name, uint64_t name_length) {
+  (void)name_length;
   assert(context == (void *)0xdeadbeef);
   return (swift_addr_t)dlsym(RTLD_DEFAULT, name);
 }
 
 int main(int argc, char **argv) {
-  if (argc != 4) {
-    fprintf(stderr, "usage: %s <libtestswift.dylib> <libswiftRemoteMirror4.dylib> "
-                    "<libswiftRemoteMirror5.dylib>\n",
+  if (argc < 2) {
+    fprintf(stderr, "usage: %s <libtestswift.dylib> <libswiftRemoteMirror.dylib ...>\n",
                     argv[0]);
     exit(1);
   }
 
   char *TestLibPath = argv[1];
-  char *Mirror4Path = argv[2];
-  char *Mirror5Path = argv[3];
 
   void *TestHandle = Load(TestLibPath);
   intptr_t (*Test)(void) = dlsym(TestHandle, "test");
 
   uintptr_t Obj = Test();
 
-  void *Mirror4Handle = Mirror4Path[0] == '-' ? NULL : Load(Mirror4Path);
-  void *Mirror5Handle = Mirror5Path[0] == '-' ? NULL : Load(Mirror5Path);
   SwiftReflectionInteropContextRef Context =
     swift_reflection_interop_createReflectionContext(
       (void *)0xdeadbeef,
-      Mirror5Handle,
-      Mirror4Handle,
       sizeof(void *),
       Free,
       ReadBytes,
@@ -95,6 +89,28 @@ int main(int argc, char **argv) {
     exit(1);
   }
 
+  for (int i = 2; i < argc; i++) {
+    void *Handle = Load(argv[i]);
+    int Success = swift_reflection_interop_addLibrary(Context, Handle);
+    if (!Success) {
+      fprintf(stderr, "Failed to add library at %s\n", argv[i]);
+      exit(1);
+    }
+  }
+  
+  int hasLegacy = 0;
+  int hasNonLegacy = 0;
+  for (int i = 0; i < Context->LibraryCount; i++) {
+    if (Context->Libraries[i].IsLegacy)
+      hasLegacy = 1;
+    else
+      hasNonLegacy = 1;
+  }
+  if (hasLegacy && !hasNonLegacy) {
+    printf("We can't run tests with only a legacy library. Giving up.\n");
+    exit(0);
+  }
+  
   uint32_t ImageCount = _dyld_image_count();
   for (uint32_t i = 0; i < ImageCount; i++) {
     swift_addr_t Image = (swift_addr_t)_dyld_get_image_header(i);

unittests/Reflection/RemoteMirrorInterop/test.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+
+# Exercise the SwiftRemoteMirrorLegacyInterop API. This works with
+# multiple versions of Swift. It builds Swift code using all versions,
+# and exercises the Interop API using various combinations of those
+# versions' Remote Mirror libraries.
+#
+# Invoke by passing the various Swift build directories as parameters.
+
+import itertools
+import os
+import subprocess
+import sys
+
+args = sys.argv[1:]
+if len(args) == 0:
+  print >> sys.stderr, "Usage:", sys.argv[0], "swift-build-dirs..."
+  print >> sys.stderr, "Note: pass paths to the swift-macosx-x86_64 directories."
+  sys.exit(1)
+
+swiftcs = [os.path.join(arg, 'bin', 'swiftc') for arg in args]
+mirrorlibs = [os.path.join(arg, 'lib', 'swift', 'macosx', 'libswiftRemoteMirror.dylib')
+              for arg in args]
+
+os.chdir(os.path.dirname(sys.argv[0]))
+
+# Build the remote mirror test harness program.
+subprocess.check_call(['clang',
+                       '-framework', 'Foundation',
+                       '-I', '../../../include/swift/SwiftRemoteMirror',
+                       '-I', '../../../include/',
+                       '-o', '/tmp/test',
+                       '-Wall', '-Wextra',
+                       '-g', 'test.m'])
+
+# Build a test library with each Swift compiler passed in.
+for i, swiftc in enumerate(swiftcs):
+  subprocess.check_call(['xcrun', swiftc, '-emit-library', 'test.swift',
+                         '-o', os.path.join('/tmp', 'libtest' + str(i) + '.dylib')])
+
+# Run the test harness with all combinations of the remote mirror libraries.
+for i in range(len(swiftcs) + 1):
+  for localMirrorlibs in itertools.combinations(mirrorlibs, i):
+    for i, arg in enumerate(args):
+      print 'Testing', arg, 'with mirror libs:'
+      for l in localMirrorlibs:
+        print '\t', l
+      callArgs = (['/tmp/test', os.path.join('/tmp', 'libtest' + str(i) + '.dylib')]
+                  + list(localMirrorlibs))
+      print ' '.join(callArgs)
+      subprocess.call(callArgs)
+      print 'DONE'
+      print ''
+    print localMirrorlibs