Merge pull request swiftlang#25473 from aschwaighofer/back_deploy_dynamic_replacement

stdlib: Add backward deployment versions for the dynamic-replacement runtime functions

Author: aschwaighofer

cmake/modules/SwiftSource.cmake

@@ -269,6 +269,7 @@ function(_compile_swift_files
   # into the new runtime.
   if (SWIFTFILE_IS_STDLIB OR SWIFTFILE_IS_SDK_OVERLAY)
     list(APPEND swift_flags "-runtime-compatibility-version" "none")
+    list(APPEND swift_flags "-disable-autolinking-runtime-compatibility-dynamic-replacements")
   endif()
 
   if (SWIFTFILE_IS_STDLIB_CORE OR SWIFTFILE_IS_SDK_OVERLAY)

include/swift/AST/ASTContext.h

@@ -590,6 +590,10 @@ class ASTContext final {
   /// Get the runtime availability of the opaque types language feature for the target platform.
   AvailabilityContext getOpaqueTypeAvailability();
 
+  /// Get the runtime availability of features introduced in the Swift 5.1
+  /// compiler for the target platform.
+  AvailabilityContext getSwift51Availability();
+
   //===--------------------------------------------------------------------===//
   // Diagnostics Helper functions
   //===--------------------------------------------------------------------===//

include/swift/AST/IRGenOptions.h

@@ -228,6 +228,7 @@ class IRGenOptions {
 
   /// Pull in runtime compatibility shim libraries by autolinking.
   Optional<llvm::VersionTuple> AutolinkRuntimeCompatibilityLibraryVersion;
+  Optional<llvm::VersionTuple> AutolinkRuntimeCompatibilityDynamicReplacementLibraryVersion;
 
   IRGenOptions()
       : DWARFVersion(2), OutputKind(IRGenOutputKind::LLVMAssembly),

include/swift/Option/Options.td

@@ -912,4 +912,10 @@ def disable_autolinking_runtime_compatibility : Flag<["-"], "disable-autolinking
   Flags<[FrontendOption]>,
   HelpText<"Do not use autolinking for runtime compatibility libraries">;
 
+def disable_autolinking_runtime_compatibility_dynamic_replacements
+    : Flag<[ "-" ], "disable-autolinking-runtime-compatibility-dynamic-replacements">,
+      Flags<[ FrontendOption ]>,
+      HelpText<"Do not use autolinking for the dynamic replacement runtime "
+               "compatibility library">;
+
 include "FrontendOptions.td"

include/swift/Runtime/Exclusivity.h

@@ -44,13 +44,19 @@ void swift_beginAccess(void *pointer, ValueBuffer *buffer,
 /// replacement function if it should be called.
 /// Returns null if the original function (which is passed in \p CurrFn) should
 /// be called.
+#ifdef __APPLE__
+__attribute__((weak_import))
+#endif
 SWIFT_RUNTIME_EXPORT
 char *swift_getFunctionReplacement(char **ReplFnPtr, char *CurrFn);
 
 /// Returns the original function of a replaced function, which is loaded from
 /// \p OrigFnPtr.
 /// This function is called from a replacement function to call the original
 /// function.
+#ifdef __APPLE__
+__attribute__((weak_import))
+#endif
 SWIFT_RUNTIME_EXPORT
 char *swift_getOrigOfReplaceable(char **OrigFnPtr);
 

include/swift/Runtime/RuntimeFnWrappersGen.h

@@ -22,6 +22,13 @@
 namespace swift {
 
 class AvailabilityContext;
+class ASTContext;
+
+enum class RuntimeAvailability {
+  AlwaysAvailable,
+  AvailableByCompatibilityLibrary,
+  ConditionallyAvailable
+};
 
 /// Generate an llvm declaration for a runtime entry with a
 /// given name, return types, argument types, attributes and
@@ -30,7 +37,8 @@ llvm::Constant *getRuntimeFn(llvm::Module &Module,
                       llvm::Constant *&cache,
                       char const *name,
                       llvm::CallingConv::ID cc,
-                      bool isWeakLinked,
+                      RuntimeAvailability availability,
+                      ASTContext *context,
                       llvm::ArrayRef<llvm::Type*> retTypes,
                       llvm::ArrayRef<llvm::Type*> argTypes,
                       llvm::ArrayRef<llvm::Attribute::AttrKind> attrs);

include/swift/Runtime/RuntimeFunctions.def

@@ -638,7 +638,7 @@ FUNCTION(GetGenericMetadata, swift_getGenericMetadata,
 //                                     const OpaqueTypeDescriptor *descriptor,
 //                                     uintptr_t index);
 FUNCTION(GetOpaqueTypeMetadata, swift_getOpaqueTypeMetadata,
-         SwiftCC, OpaqueTypeAvailability,
+         SwiftCC, ConditionallyAvailable,
          RETURNS(TypeMetadataResponseTy),
          ARGS(SizeTy, Int8PtrTy, OpaqueTypeDescriptorPtrTy, SizeTy),
          ATTRS(NoUnwind, ReadOnly))
@@ -647,7 +647,7 @@ FUNCTION(GetOpaqueTypeMetadata, swift_getOpaqueTypeMetadata,
 //                                     const OpaqueTypeDescriptor *descriptor,
 //                                     uintptr_t index);
 FUNCTION(GetOpaqueTypeConformance, swift_getOpaqueTypeConformance,
-         SwiftCC, OpaqueTypeAvailability,
+         SwiftCC, ConditionallyAvailable,
          RETURNS(WitnessTablePtrTy),
          ARGS(Int8PtrTy, OpaqueTypeDescriptorPtrTy, SizeTy),
          ATTRS(NoUnwind, ReadOnly))
@@ -1225,12 +1225,14 @@ FUNCTION(EndAccess, swift_endAccess, C_CC, AlwaysAvailable,
          ARGS(getFixedBufferTy()->getPointerTo()),
          ATTRS(NoUnwind))
 
-FUNCTION(GetOrigOfReplaceable, swift_getOrigOfReplaceable, C_CC, AlwaysAvailable,
+FUNCTION(GetOrigOfReplaceable, swift_getOrigOfReplaceable, C_CC,
+         AvailableByCompatibilityLibrary,
          RETURNS(FunctionPtrTy),
          ARGS(FunctionPtrTy->getPointerTo()),
          ATTRS(NoUnwind))
 
-FUNCTION(GetReplacement, swift_getFunctionReplacement, C_CC, AlwaysAvailable,
+FUNCTION(GetReplacement, swift_getFunctionReplacement, C_CC,
+         AvailableByCompatibilityLibrary,
          RETURNS(FunctionPtrTy),
          ARGS(FunctionPtrTy->getPointerTo(), FunctionPtrTy),
          ATTRS(NoUnwind))

lib/AST/Availability.cpp

@@ -218,6 +218,10 @@ AvailabilityContext AvailabilityInference::inferForType(Type t) {
 }
 
 AvailabilityContext ASTContext::getOpaqueTypeAvailability() {
+  return getSwift51Availability();
+}
+
+AvailabilityContext ASTContext::getSwift51Availability() {
   auto target = LangOpts.Target;
 
   if (target.isMacOSX()) {

lib/Driver/DarwinToolChains.cpp

@@ -427,6 +427,22 @@ toolchains::Darwin::constructInvocation(const LinkJobAction &job,
     }
   }
 
+  if (job.getKind() == LinkKind::Executable) {
+    if (runtimeCompatibilityVersion)
+      if (*runtimeCompatibilityVersion <= llvm::VersionTuple(5, 0)) {
+        // Swift 5.0 dynamic replacement compatibility library.
+        SmallString<128> BackDeployLib;
+        BackDeployLib.append(RuntimeLibPath);
+        llvm::sys::path::append(BackDeployLib,
+                                "libswiftCompatibilityDynamicReplacements.a");
+
+        if (llvm::sys::fs::exists(BackDeployLib)) {
+          Arguments.push_back("-force_load");
+          Arguments.push_back(context.Args.MakeArgString(BackDeployLib));
+        }
+      }
+  }
+
   // Link the standard library.
   Arguments.push_back("-L");
   if (context.Args.hasFlag(options::OPT_static_stdlib,

lib/Driver/ToolChains.cpp

@@ -445,7 +445,12 @@ ToolChain::constructInvocation(const CompileJobAction &job,
     Arguments.push_back("-runtime-compatibility-version");
     Arguments.push_back(arg->getValue());
   }
-                                 
+
+  context.Args.AddLastArg(
+      Arguments,
+      options::
+          OPT_disable_autolinking_runtime_compatibility_dynamic_replacements);
+
   return II;
 }