Merge pull request #69542 from mikeash/retain-release-override-optional

mikeash · web-flow · commit 967c5c6a7576 · 2023-11-08T19:51:29.000-05:00
[Runtime] Add option to remove override point for retain/release.
diff --git a/include/swift/Runtime/InstrumentsSupport.h b/include/swift/Runtime/InstrumentsSupport.h
@@ -23,6 +23,8 @@
 
 namespace swift {
 
+#ifdef SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+
 // liboainject patches the function pointers and calls the functions below.
 SWIFT_RUNTIME_EXPORT
 HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_allocObject)(
@@ -60,6 +62,8 @@ size_t _swift_indexToSize(size_t idx);
 SWIFT_RUNTIME_EXPORT
 void _swift_zone_init(void);
 
+#endif // SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+
 }
 
 #endif
diff --git a/stdlib/cmake/modules/AddSwiftStdlib.cmake b/stdlib/cmake/modules/AddSwiftStdlib.cmake
@@ -449,6 +449,10 @@ function(_add_target_variant_c_compile_flags)
     list(APPEND result "-DSWIFT_STDLIB_USE_RELATIVE_PROTOCOL_WITNESS_TABLES")
   endif()
 
+  if(SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE)
+    list(APPEND result "-DSWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE")
+  endif()
+
   list(APPEND result ${SWIFT_STDLIB_EXTRA_C_COMPILE_FLAGS})
 
   set("${CFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
diff --git a/stdlib/cmake/modules/StdlibOptions.cmake b/stdlib/cmake/modules/StdlibOptions.cmake
@@ -268,6 +268,10 @@ option(SWIFT_STDLIB_INSTALL_PARENT_MODULE_FOR_SHIMS
        "Install a parent module map for Swift shims."
        ${SWIFT_STDLIB_INSTALL_PARENT_MODULE_FOR_SHIMS_default})
 
+option(SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+       "Allow retain/release functions to be overridden by indirecting through function pointers."
+       TRUE)
+
 set(SWIFT_RUNTIME_FIXED_BACKTRACER_PATH "" CACHE STRING
   "If set, provides a fixed path to the swift-backtrace binary.  This
    will disable dynamic determination of the path and will also disable
diff --git a/stdlib/cmake/modules/SwiftSource.cmake b/stdlib/cmake/modules/SwiftSource.cmake
@@ -358,6 +358,10 @@ function(_add_target_variant_swift_compile_flags
     list(APPEND result "-D" "SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY")
   endif()
 
+  if(SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE)
+    list(APPEND result "-D" "SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE")
+  endif()
+
   string(TOUPPER "${SWIFT_SDK_${sdk}_THREADING_PACKAGE}" _threading_package)
   list(APPEND result "-D" "SWIFT_THREADING_${_threading_package}")
 
diff --git a/stdlib/public/runtime/HeapObject.cpp b/stdlib/public/runtime/HeapObject.cpp
@@ -107,6 +107,9 @@ static void _swift_release_n_(HeapObject *object, uint32_t n)
   asm("__swift_release_n_");
 static HeapObject *_swift_tryRetain_(HeapObject *object)
   asm("__swift_tryRetain_");
+
+#ifdef SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+
 #define CALL_IMPL(name, args) do { \
     void *fptr; \
     memcpy(&fptr, (void *)&_ ## name, sizeof(fptr)); \
@@ -117,6 +120,14 @@ static HeapObject *_swift_tryRetain_(HeapObject *object)
     return _ ## name ## _ args; \
 } while(0)
 
+#else
+
+// If retain/release etc. aren't overridable, just call the real implementation.
+#define CALL_IMPL(name, args) \
+    return _ ## name ## _ args;
+
+#endif
+
 #if SWIFT_STDLIB_HAS_MALLOC_TYPE
 static malloc_type_summary_t
 computeMallocTypeSummary(const HeapMetadata *heapMetadata) {
@@ -212,6 +223,35 @@ static malloc_type_id_t getMallocTypeId(const HeapMetadata *heapMetadata) {
 }
 #endif // SWIFT_STDLIB_HAS_MALLOC_TYPE
 
+#ifdef SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+
+SWIFT_RUNTIME_EXPORT
+HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_allocObject)(
+    HeapMetadata const *metadata, size_t requiredSize,
+    size_t requiredAlignmentMask) = _swift_allocObject_;
+
+SWIFT_RUNTIME_EXPORT
+HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_retain)(HeapObject *object) =
+    _swift_retain_;
+
+SWIFT_RUNTIME_EXPORT
+HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_retain_n)(
+    HeapObject *object, uint32_t n) = _swift_retain_n_;
+
+SWIFT_RUNTIME_EXPORT
+void (*SWIFT_RT_DECLARE_ENTRY _swift_release)(HeapObject *object) =
+    _swift_release_;
+
+SWIFT_RUNTIME_EXPORT
+void (*SWIFT_RT_DECLARE_ENTRY _swift_release_n)(HeapObject *object,
+                                                uint32_t n) = _swift_release_n_;
+
+SWIFT_RUNTIME_EXPORT
+HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_tryRetain)(HeapObject *object) =
+    _swift_tryRetain_;
+
+#endif // SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE
+
 static HeapObject *_swift_allocObject_(HeapMetadata const *metadata,
                                        size_t requiredSize,
                                        size_t requiredAlignmentMask) {
@@ -243,11 +283,6 @@ HeapObject *swift::swift_allocObject(HeapMetadata const *metadata,
   CALL_IMPL(swift_allocObject, (metadata, requiredSize, requiredAlignmentMask));
 }
 
-SWIFT_RUNTIME_EXPORT
-HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_allocObject)(
-    HeapMetadata const *metadata, size_t requiredSize,
-    size_t requiredAlignmentMask) = _swift_allocObject_;
-
 HeapObject *
 swift::swift_initStackObject(HeapMetadata const *metadata,
                              HeapObject *object) {
@@ -465,10 +500,6 @@ HeapObject *swift::swift_retain(HeapObject *object) {
 
 CUSTOM_RR_ENTRYPOINTS_DEFINE_ENTRYPOINTS(swift_retain)
 
-SWIFT_RUNTIME_EXPORT
-HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_retain)(HeapObject *object) =
-    _swift_retain_;
-
 HeapObject *swift::swift_nonatomic_retain(HeapObject *object) {
   SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_retain);
   if (isValidPointerForNativeRetain(object))
@@ -492,10 +523,6 @@ HeapObject *swift::swift_retain_n(HeapObject *object, uint32_t n) {
 #endif
 }
 
-SWIFT_RUNTIME_EXPORT
-HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_retain_n)(
-    HeapObject *object, uint32_t n) = _swift_retain_n_;
-
 HeapObject *swift::swift_nonatomic_retain_n(HeapObject *object, uint32_t n) {
   SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_retain_n);
   if (isValidPointerForNativeRetain(object))
@@ -520,10 +547,6 @@ void swift::swift_release(HeapObject *object) {
 
 CUSTOM_RR_ENTRYPOINTS_DEFINE_ENTRYPOINTS(swift_release)
 
-SWIFT_RUNTIME_EXPORT
-void (*SWIFT_RT_DECLARE_ENTRY _swift_release)(HeapObject *object) =
-    _swift_release_;
-
 void swift::swift_nonatomic_release(HeapObject *object) {
   SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_release);
   if (isValidPointerForNativeRetain(object))
@@ -545,10 +568,6 @@ void swift::swift_release_n(HeapObject *object, uint32_t n) {
 #endif
 }
 
-SWIFT_RUNTIME_EXPORT
-void (*SWIFT_RT_DECLARE_ENTRY _swift_release_n)(HeapObject *object,
-                                                uint32_t n) = _swift_release_n_;
-
 void swift::swift_nonatomic_release_n(HeapObject *object, uint32_t n) {
   SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_release_n);
   if (isValidPointerForNativeRetain(object))
@@ -706,10 +725,6 @@ HeapObject *swift::swift_tryRetain(HeapObject *object) {
   CALL_IMPL(swift_tryRetain, (object));
 }
 
-SWIFT_RUNTIME_EXPORT
-HeapObject *(*SWIFT_RT_DECLARE_ENTRY _swift_tryRetain)(HeapObject *object) =
-    _swift_tryRetain_;
-
 bool swift::swift_isDeallocating(HeapObject *object) {
   if (!isValidPointerForNativeRetain(object))
     return false;
diff --git a/utils/build-presets.ini b/utils/build-presets.ini
@@ -2633,6 +2633,7 @@ build-swift-stdlib-unicode-data=0
 build-swift-stdlib-static-print=1
 darwin-crash-reporter-client=0
 swift-stdlib-use-relative-protocol-witness-tables=1
+swift-stdlib-overridable-retain-release=0
 
 [preset: stdlib_S_standalone_minimal_macho_x86_64,build]
 mixin-preset=
diff --git a/utils/build-script-impl b/utils/build-script-impl
@@ -246,6 +246,7 @@ KNOWN_SETTINGS=(
     swift-earlyswiftsyntax                        "0"               "use the early SwiftSyntax"
     swift-enable-backtracing                      "1"               "whether to build the backtracing support"
     swift-runtime-fixed-backtracer-path           ""                "if set, use a fixed path for the backtracer"
+    swift-stdlib-overridable-retain-release       "1"               "whether to allow retain/release functions to be overridden by indirecting through function pointers"
 
     ## FREESTANDING Stdlib Options
     swift-freestanding-flavor                     ""                "when building the FREESTANDING stdlib, which build style to use (options: apple, linux)"
@@ -1878,6 +1879,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DLIBDISPATCH_CMAKE_BUILD_TYPE:STRING="${LIBDISPATCH_BUILD_TYPE}"
                     -DSWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE:PATH="${SWIFT_SYNTAX_SOURCE_DIR}"
                     -DSWIFT_ENABLE_BACKTRACING:BOOL=$(true_false "${SWIFT_ENABLE_BACKTRACING}")
+                    -DSWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE:BOOL=$(true_false "${SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE}")
                     "${swift_cmake_options[@]}"
                 )
 
diff --git a/utils/swift_build_support/swift_build_support/products/minimalstdlib.py b/utils/swift_build_support/swift_build_support/products/minimalstdlib.py
@@ -167,6 +167,8 @@ def build(self, host_target):
         self.cmake_options.define(
             'SWIFT_STDLIB_USE_RELATIVE_PROTOCOL_WITNESS_TABLES:BOOL', 'TRUE')
         self.cmake_options.define('SWIFT_THREADING_PACKAGE:STRING', 'none')
+        self.cmake_options.define(
+            'SWIFT_STDLIB_OVERRIDABLE_RETAIN_RELEASE:BOOL', 'FALSE')
 
         # Build!
         self.build_with_cmake(["swift-stdlib-freestanding"], build_variant, [],
