Merge branch 'master' into mracek/arm64e

include/swift/Remote/InProcessMemoryReader.h

@@ -21,6 +21,10 @@
 
 #include <cstring>
 
+#if defined(__APPLE__) && defined(__MACH__)
+#include <TargetConditionals.h>
+#endif
+
 namespace swift {
 namespace remote {
 
@@ -29,28 +33,62 @@ namespace remote {
 class InProcessMemoryReader final : public MemoryReader {
   bool queryDataLayout(DataLayoutQueryType type, void *inBuffer,
                        void *outBuffer) override {
-    switch (type) {
-      case DLQ_GetPointerSize: {
-        auto result = static_cast<uint8_t *>(outBuffer);
-        *result = sizeof(void *);
-        return true;
-      }
-      case DLQ_GetSizeSize: {
-        auto result = static_cast<uint8_t *>(outBuffer);
-        *result = sizeof(size_t);
-        return true;
-      }
-      case DLQ_GetPtrAuthMask: {
-        auto result = static_cast<uintptr_t *>(outBuffer);
-#if __has_feature(ptrauth_calls)
-        *result = (uintptr_t)ptrauth_strip((void*)0x0007ffffffffffff, 0);
+#if defined(__APPLE__) && __APPLE__
+    auto applePlatform = true;
 #else
-        *result = (uintptr_t)~0ull;
+    auto applePlatform = false;
+#endif
+#if defined(__APPLE__) && __APPLE__ && ((defined(TARGET_OS_IOS) && TARGET_OS_IOS) || (defined(TARGET_OS_IOS) && TARGET_OS_WATCH) || (defined(TARGET_OS_TV) && TARGET_OS_TV))
+    auto iosDerivedPlatform = true;
+#else
+    auto iosDerivedPlatform = false;
 #endif
-        return true;
-      }
-    }
 
+    switch (type) {
+    case DLQ_GetPointerSize: {
+      auto result = static_cast<uint8_t *>(outBuffer);
+      *result = sizeof(void *);
+      return true;
+    }
+    case DLQ_GetSizeSize: {
+      auto result = static_cast<uint8_t *>(outBuffer);
+      *result = sizeof(size_t);
+      return true;
+    }
+    case DLQ_GetPtrAuthMask: {
+      auto result = static_cast<uintptr_t *>(outBuffer);
+#if __has_feature(ptrauth_calls)
+      *result = (uintptr_t)ptrauth_strip((void*)0x0007ffffffffffff, 0);
+#else
+      *result = (uintptr_t)~0ull;
+#endif
+      return true;
+    }
+    case DLQ_GetObjCReservedLowBits: {
+      auto result = static_cast<uint8_t *>(outBuffer);
+      if (applePlatform && !iosDerivedPlatform && (sizeof(void *) == 8)) {
+        // Obj-C reserves low bit on 64-bit macOS only.
+        // Other Apple platforms don't reserve this bit (even when
+        // running on x86_64-based simulators).
+        *result = 1;
+      } else {
+        *result = 0;
+      }
+      return true;
+    }
+    case DLQ_GetLeastValidPointerValue: {
+      auto result = static_cast<uint64_t *>(outBuffer);
+      if (applePlatform && (sizeof(void *) == 8)) {
+        // Swift reserves the first 4GiB on Apple 64-bit platforms
+        *result = 0x100000000;
+        return 1;
+      } else {
+        // Swift reserves the first 4KiB everywhere else
+        *result = 0x1000;
+      }
+      return true;
+    }
+    }
     return false;
   }