Merge pull request #82963 from meg-gupta/disablefso2

[6.2] Disable function signature optimization on functions with lifetime dependencies

Author: meg-gupta

lib/SILOptimizer/FunctionSignatureTransforms/DeadArgumentTransform.cpp

@@ -28,6 +28,16 @@ bool FunctionSignatureTransform::DeadArgumentAnalyzeParameters() {
 
   // Did we decide we should optimize any parameter?
   SILFunction *F = TransformDescriptor.OriginalFunction;
+
+  // If a function has lifetime dependencies, disable FSO's dead param
+  // optimization.  Dead params maybe dependency sources and we should not
+  // delete them. It is also problematic to dead code params that are not
+  // dependency sources, since lifetime dependent sources are stored as indices
+  // and deleting dead parameters will require recomputation of these indices.
+  if (F->getLoweredFunctionType()->hasLifetimeDependencies()) {
+    return false;
+  }
+
   bool SignatureOptimize = false;
   auto Args = F->begin()->getSILFunctionArguments();
   auto OrigShouldModifySelfArgument =

test/SILOptimizer/functionsigopts.sil

@@ -1,5 +1,8 @@
-// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts %s | %FileCheck %s
-// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts %s | %FileCheck -check-prefix=CHECK-NEGATIVE %s
+// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts -enable-experimental-feature Lifetimes %s | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -sil-inline-generics -enable-sil-verify-all -inline -function-signature-opts -enable-experimental-feature Lifetimes %s | %FileCheck -check-prefix=CHECK-NEGATIVE %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 import Builtin
 import Swift
@@ -1832,6 +1835,28 @@ bb0(%0 : $ValueGenericType<N>):
   return %2 : $Int
 }
 
+struct NE<T> : ~Escapable where T : ~Escapable {
+  @_lifetime(copy t)
+  init(_ t: borrowing T)
+}
+
+// CHECK-NOT: sil [serialized] [signature_optimized_thunk] [always_inline] @neinit :
+sil [noinline] @neinit : $@convention(method) <T where T : ~Escapable> (@in_guaranteed T, @thin NE<T>.Type) -> @lifetime(copy 0) @owned NE<T> {
+bb0(%0 : @noImplicitCopy $*T, %1 : $@thin NE<T>.Type):
+  debug_value [moveable_value_debuginfo] %0, let, name "t", argno 1, expr op_deref
+  %3 = struct $NE<T> ()
+  return %3
+}
+
+sil hidden @neinit_caller : $@convention(thin) <T where T : ~Escapable> (@in_guaranteed T) -> @lifetime(copy 0) @owned NE<T> {
+bb0(%0 : @noImplicitCopy $*T):
+  debug_value [moveable_value_debuginfo] %0, let, name "t", argno 1, expr op_deref
+  %2 = metatype $@thin NE<T>.Type
+  %3 = function_ref @neinit : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed τ_0_0, @thin NE<τ_0_0>.Type) -> @lifetime(copy 0) @owned NE<τ_0_0>
+  %4 = apply %3<T>(%0, %2) : $@convention(method) <τ_0_0 where τ_0_0 : ~Escapable> (@in_guaranteed τ_0_0, @thin NE<τ_0_0>.Type) -> @lifetime(copy 0) @owned NE<τ_0_0>
+  return %4
+}
+
 // CHECK-LABEL: sil shared @$s36exploded_release_to_guaranteed_paramTf4gX_n
 // CHECK: bb0([[INPUT_ARG0:%[0-9]+]] : $Int):
 // CHECK-NOT: strong_release

test/SILOptimizer/functionsigopts_crash.swift

@@ -1,4 +1,7 @@
-// RUN: %target-swift-frontend -module-name main -O -emit-sil -primary-file %s | %FileCheck %s
+// RUN: %target-swift-frontend -module-name main -O -emit-sil -primary-file %s -enable-experimental-feature Lifetimes | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: swift_feature_Lifetimes
 
 protocol P {
   func foo()
@@ -53,3 +56,14 @@ extension Array: IP {
     }
   }
 }
+
+struct NE<T : ~Escapable> : ~Escapable {
+  @_lifetime(copy t)
+  init(_ t: borrowing T) {}
+}
+
+@_lifetime(copy t)
+func getNE<T : ~Escapable>(_ t: borrowing T) -> NE<T> {
+  return NE(t)
+}
+