Merge pull request #62427 from tshortli/back-deployed-attr-skip-noninlinable-function-bodies

Serialization: Update `-experimental-skip-non-inlinable-function-bodies` SIL verification for `@_backDeploy`

Author: tshortli

lib/SILOptimizer/UtilityPasses/SILSkippingChecker.cpp

@@ -72,6 +72,15 @@ static bool shouldHaveSkippedFunction(const SILFunction &F) {
       return false;
   }
 
+  // Functions with @_backDeploy may be copied into the client, so they
+  // shouldn't be skipped. The SILFunction that may be copied into the client
+  // should be serialized and therefore is already handled above. However, a
+  // second resilient SILFunction is also emitted for back deployed functions.
+  // Since the body of the function as written was not skipped, it's expected
+  // that we see the SILFunction for the resilient copy here.
+  if (func->isBackDeployed())
+    return false;
+
   // If none of those conditions trip, then this is something that _should_
   // be serialized in the module even when we're skipping non-inlinable
   // function bodies.

test/Serialization/back-deployed-attr-skip-noninlinable-function-bodies.swift

@@ -0,0 +1,5 @@
+// RUN: %target-swift-frontend -parse-as-library -enable-library-evolution -emit-module -module-name Test -experimental-skip-non-inlinable-function-bodies %s
+
+@available(SwiftStdlib 5.6, *)
+@_backDeploy(before: SwiftStdlib 5.7)
+public func foo() {}