LifetimeDependenceDiagnostics; handle @_unsafeNonescapableResult.

Author: atrick

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift

@@ -43,9 +43,21 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
     }
   }
   for instruction in function.instructions {
-    guard let markDep = instruction as? MarkDependenceInst else { continue }
-    if let lifetimeDep = LifetimeDependence(markDep, context) {
-      analyze(dependence: lifetimeDep, context)
+    if let markDep = instruction as? MarkDependenceInst {
+      if let lifetimeDep = LifetimeDependence(markDep, context) {
+        analyze(dependence: lifetimeDep, context)
+      }
+      continue
+    }
+    if let apply = instruction as? FullApplySite {
+      // Handle ~Escapable results that do not have a lifetime
+      // dependence (@_unsafeNonescapableResult).
+      apply.dependentValues.forEach {
+        if let lifetimeDep = LifetimeDependence(applyResult: $0, context) {
+          analyze(dependence: lifetimeDep, context)
+        }
+      }
+      continue
     }
   }
 }

SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift

@@ -174,6 +174,20 @@ extension LifetimeDependence {
     self.dependentValue = arg
   }
 
+  // Handle ~Escapable results that do not have a lifetime dependence
+  // (@_unsafeNonescapableResult).
+  init?(applyResult value: Value, _ context: some Context) {
+    if value.type.isEscapable {
+      return nil
+    }
+    let applySite = value.definingInstruction as! FullApplySite
+    if applySite.calleeArgumentConventions.resultDependencies != nil {
+      return nil
+    }
+    self.scope = Scope(base: value, context)!
+    self.dependentValue = value
+  }
+
   /// Construct LifetimeDependence from mark_dependence [nonescaping]
   ///
   /// TODO: Add SIL verification that all mark_depedence [nonescaping]

lib/AST/ASTPrinter.cpp

@@ -7599,9 +7599,9 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
       }
       sub->Printer << ") -> ";
 
-      auto *lifetimeDependenceInfo = T->getLifetimeDependenceInfo();
-      if (lifetimeDependenceInfo && !lifetimeDependenceInfo->empty()) {
-        sub->Printer << lifetimeDependenceInfo->getString() << " ";
+      auto lifetimeDependenceInfo = T->getLifetimeDependenceInfo();
+      if (!lifetimeDependenceInfo.empty()) {
+        sub->Printer << lifetimeDependenceInfo.getString() << " ";
       }
 
       bool parenthesizeResults = mustParenthesizeResults(T);