Enable 'StopOptimizationAfterSerialization' SIL Option for explicit

'-compile-module-from-interface' tasks

Author: artemcm

lib/Frontend/CompilerInvocation.cpp

@@ -1941,7 +1941,8 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
 
   // If we're only emitting a module, stop optimizations once we've serialized
   // the SIL for the module.
-  if (FEOpts.RequestedAction == FrontendOptions::ActionType::EmitModuleOnly)
+  if (FEOpts.RequestedAction == FrontendOptions::ActionType::EmitModuleOnly ||
+      FEOpts.RequestedAction == FrontendOptions::ActionType::CompileModuleFromInterface)
     Opts.StopOptimizationAfterSerialization = true;
 
   // Propagate the typechecker's understanding of

test/SILOptimizer/stop_after_explicit_interface.swift

@@ -0,0 +1,22 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/Foo)
+// RUN: %target-swift-frontend -swift-version 5 -O -emit-module %s -emit-module-path %t/Foo/Foo.swiftmodule -module-name Foo -emit-module-interface-path %t/Foo/Foo.swiftinterface -enable-library-evolution
+
+// RUN: %target-swift-frontend -swift-version 5 -compile-module-from-interface -module-name Foo -o %t/Foo/FooFromInterface.swiftmodule -O -Xllvm -sil-print-after=inline %t/Foo/Foo.swiftinterface 2>&1 | %FileCheck %s --check-prefix SKIPPING
+
+// This test ensures that we don't run the Perf Inliner after serializing a
+// module, if we're stopping optimizations after serializing. 
+
+@inline(never)
+public func _blackHole(_ x: Int) {}
+
+@inlinable
+public func inlinableFunction(_ x: Int) -> Int {
+  return x + 1
+}
+
+public func caller() {
+  _blackHole(inlinableFunction(20))
+}
+
+// SKIPPING-NOT: *** SIL function after {{.*}}, stage MidLevel,Function, pass {{.*}}: PerfInliner (inline)