Remove unused infrastructure added for runtime attributes (swiftlang#62971)

Author: grynspan

stdlib/public/SwiftShims/swift/shims/MetadataSections.h

@@ -45,7 +45,8 @@ typedef struct MetadataSectionRange {
 ///
 /// \warning If you change the size of this structure by adding fields, it is an
 ///   ABI-breaking change on platforms that use it. Make sure to increment
-///   \c CurrentSectionMetadataVersion if you do.
+///   \c CurrentSectionMetadataVersion if you do. To minimize impact, always add
+///   new fields to the \em end of the structure.
 struct MetadataSections {
   __swift_uintptr_t version;
 

stdlib/public/runtime/CMakeLists.txt

@@ -70,7 +70,6 @@ set(swift_runtime_sources
     SwiftTLSContext.cpp
     ThreadingError.cpp
     AccessibleFunction.cpp
-    RuntimeAttribute.cpp
     Win32.cpp)
 
 # Acknowledge that the following sources are known.

stdlib/public/runtime/ImageInspection.h

@@ -55,9 +55,6 @@ void initializeDynamicReplacementLookup();
 /// Load the metadata from the image necessary to find functions by name.
 void initializeAccessibleFunctionsLookup();
 
-/// Load the metadata from the image necessary to find runtime metadata.
-void initializeRuntimeAttributesLookup();
-
 // Callbacks to register metadata from an image to the runtime.
 void addImageProtocolsBlockCallback(const void *baseAddress,
                                     const void *start, uintptr_t size);
@@ -85,12 +82,6 @@ void addImageAccessibleFunctionsBlockCallback(const void *baseAddress,
 void addImageAccessibleFunctionsBlockCallbackUnsafe(const void *baseAddress,
                                                     const void *start,
                                                     uintptr_t size);
-void addImageRuntimeAttributesBlockCallback(const void *baseAddress,
-                                            const void *start,
-                                            uintptr_t size);
-void addImageRuntimeAttributesBlockCallbackUnsafe(const void *baseAddress,
-                                                  const void *start,
-                                                  uintptr_t size);
 
 } // end namespace swift
 

stdlib/public/runtime/ImageInspectionCommon.cpp

@@ -129,15 +129,6 @@ void swift_addNewDSOImage(swift::MetadataSections *sections) {
     swift::addImageAccessibleFunctionsBlockCallback(
         baseAddress, functions, accessible_funcs_section.length);
 
-  if (sections->version >= 3) {
-    const auto &runtime_attribs_section = sections->swift5_runtime_attributes;
-    const void *functions =
-        reinterpret_cast<void *>(runtime_attribs_section.start);
-    if (runtime_attribs_section.length)
-      swift::addImageRuntimeAttributesBlockCallback(
-          baseAddress, functions, runtime_attribs_section.length);
-  }
-
   // Register this section for future enumeration by clients. This should occur
   // after this function has done all other relevant work to avoid a race
   // condition when someone calls swift_enumerateAllMetadataSections() on
@@ -177,9 +168,6 @@ void swift::initializeDynamicReplacementLookup() {
 void swift::initializeAccessibleFunctionsLookup() {
 }
 
-void swift::initializeRuntimeAttributesLookup() {
-}
-
 #ifndef NDEBUG
 
 SWIFT_RUNTIME_EXPORT

stdlib/public/runtime/ImageInspectionCommon.h

@@ -37,9 +37,6 @@
 /// The Mach-O section name for the section containing accessible functions.
 /// This lives within SEG_TEXT.
 #define MachOAccessibleFunctionsSection "__swift5_acfuncs"
-/// The Mach-O section name for the section containing runtime attributes.
-/// This lives within SEG_TEXT.
-#define MachORuntimeAttributesSection "__swift5_rattrs"
 
 #define MachOTextSegment "__TEXT"
 

stdlib/public/runtime/ImageInspectionMachO.cpp

@@ -45,8 +45,6 @@ constexpr const char DynamicReplacementSomeSection[] =
     MachODynamicReplacementSomeSection;
 constexpr const char AccessibleFunctionsSection[] =
     MachOAccessibleFunctionsSection;
-constexpr const char RuntimeAttributesSection[] =
-    MachORuntimeAttributesSection;
 constexpr const char TextSegment[] = MachOTextSegment;
 
 #if __POINTER_WIDTH__ == 64
@@ -173,11 +171,5 @@ void swift::initializeAccessibleFunctionsLookup() {
                        addImageAccessibleFunctionsBlockCallbackUnsafe>);
 }
 
-void swift::initializeRuntimeAttributesLookup() {
-  REGISTER_FUNC(
-      addImageCallback<TextSegment, RuntimeAttributesSection,
-                       addImageRuntimeAttributesBlockCallbackUnsafe>);
-}
-
 #endif // defined(__APPLE__) && defined(__MACH__) &&
        // !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)

stdlib/public/runtime/ImageInspectionStatic.cpp

@@ -86,14 +86,5 @@ void swift::initializeAccessibleFunctionsLookup() {
     return;
   addImageAccessibleFunctionsBlockCallbackUnsafe(__dso_handle, start, size);
 }
-void swift::initializeRuntimeAttributesLookup() {
-  void *start;
-  uintptr_t size;
-  GET_SECTION_START_AND_SIZE(start, size, MachOTextSegment,
-                             MachORuntimeAttributesSection);
-  if (start == nullptr || size == 0)
-    return;
-  addImageRuntimeAttributesBlockCallbackUnsafe(__dso_handle, start, size);
-}
 
 #endif // defined(__MACH__) && defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)