Merge pull request #29569 from aschwaighofer/silgen_fix_withoutActuallyEscaping_c_closure

SILGen: Fix withoutActuallyEscaping of 'c' closures

Author: aschwaighofer

lib/SILGen/SILGenExpr.cpp

@@ -5023,13 +5023,17 @@ RValue RValueEmitter::visitMakeTemporarilyEscapableExpr(
     return visit(E->getSubExpr(), C);
   };
 
-  // Handle @convention(block). No withoutActuallyEscaping verification yet.
-  if (silFnTy->getExtInfo().getRepresentation() !=
-      SILFunctionTypeRepresentation::Thick) {
+  // Handle @convention(block) an @convention(c). No withoutActuallyEscaping
+  // verification yet.
+  auto closureRepresentation = silFnTy->getExtInfo().getRepresentation();
+  if (closureRepresentation != SILFunctionTypeRepresentation::Thick) {
     auto escapingClosure =
         SGF.B.createConvertFunction(E, functionValue, escapingFnTy,
                                     /*WithoutActuallyEscaping=*/true);
-    return visitSubExpr(escapingClosure, true /*isClosureConsumable*/);
+    bool isBlockConvention =
+        closureRepresentation == SILFunctionTypeRepresentation::Block;
+    return visitSubExpr(escapingClosure,
+                        isBlockConvention /*isClosureConsumable*/);
   }
 
   // Convert it to an escaping function value.

test/SILGen/without_actually_escaping.swift

@@ -100,3 +100,16 @@ func withoutActuallyEscapingConflict() {
     modifyAndPerform(&localVar, closure: $0)
   }
 }
+
+// CHECK-LABEL: sil [ossa] @$s25without_actually_escaping0A25ActuallyEscapingCFunction8functionyyyXC_tF
+// CHECK: bb0([[ARG:%.*]] : $@convention(c) @noescape () -> ()):
+// CHECK:   [[E:%.*]] = convert_function [[ARG]] : $@convention(c) @noescape () -> () to [without_actually_escaping] $@convention(c) () -> ()
+// CHECK:   [[F:%.*]] = function_ref @$s25without_actually_escaping0A25ActuallyEscapingCFunction8functionyyyXC_tFyyyXCXEfU_ : $@convention(thin) (@convention(c) () -> ()) -> ()
+// CHECK:   apply [[F]]([[E]]) : $@convention(thin) (@convention(c) () -> ()) -> ()
+public func withoutActuallyEscapingCFunction(function: (@convention(c) () -> Void)) {
+  withoutActuallyEscaping(function) { f in
+    var pointer: UnsafeRawPointer? = nil
+    pointer = unsafeBitCast(f, to: UnsafeRawPointer.self)
+    print(pointer)
+  }
+}