[cxx-interop][SwiftCompilerSources] Do not use SWIFT_IMPORT_UNSAFE with BridgedOwnedString

`SWIFT_IMPORT_UNSAFE` is an escape hatch that can be used to make the Swift compiler ignore its usual safety heuristics for C++ types.

`BridgedOwnedString` fits into the definition of a self-contained C++ type in Swift: it manages the lifetimes of its own fields.

This removes the usages of `SWIFT_IMPORT_UNSAFE` for C++ functions that return `BridgedOwnedString`, and annotates `BridgedOwnedString` as a self-contained type.

Author: egorzhdan

include/swift/Basic/BasicBridging.h

@@ -234,7 +234,7 @@ class BridgedOwnedString {
 #endif
 
   void destroy() const;
-};
+} SWIFT_SELF_CONTAINED;
 
 SWIFT_NAME("getter:BridgedOwnedString.data(self:)")
 BRIDGED_INLINE 

include/swift/Basic/Compiler.h

@@ -90,6 +90,13 @@
 #define SWIFT_IMPORT_UNSAFE
 #endif
 
+/// Same as `SWIFT_SELF_CONTAINED` in <swift/bridging>.
+#if __has_attribute(swift_attr)
+#define SWIFT_SELF_CONTAINED __attribute__((swift_attr("import_owned")))
+#else
+#define SWIFT_SELF_CONTAINED
+#endif
+
 #ifdef __GNUC__
 #define SWIFT_ATTRIBUTE_NORETURN __attribute__((noreturn))
 #elif defined(_MSC_VER)

include/swift/SIL/SILBridging.h

@@ -267,7 +267,7 @@ struct BridgedLifetimeDependenceInfo {
   BRIDGED_INLINE bool checkScope(SwiftInt index) const;
   BRIDGED_INLINE SwiftInt getTargetIndex() const;
 
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
+  BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
 };
 
 struct BridgedLifetimeDependenceInfoArray {
@@ -313,7 +313,7 @@ struct BridgedASTType {
   }
 #endif
 
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
+  BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
 
   BRIDGED_INLINE bool hasTypeParameter() const;
 
@@ -394,7 +394,7 @@ struct BridgedType {
   }
 #endif
 
-  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
+  BRIDGED_INLINE BridgedOwnedString getDebugDescription() const;
   BRIDGED_INLINE bool isNull() const;
   BRIDGED_INLINE bool isAddress() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getAddressType() const;
@@ -486,7 +486,7 @@ struct BridgedValue {
 
   Kind getKind() const;
   BRIDGED_INLINE swift::ValueBase * _Nonnull getSILValue() const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedOperand getFirstUse() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getType() const;
   BRIDGED_INLINE Ownership getOwnership() const;
@@ -582,7 +582,7 @@ struct BridgedLocation {
   }
 #endif
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation getAutogeneratedLocation() const;
   BRIDGED_INLINE bool hasValidLineNumber() const;
   BRIDGED_INLINE bool isAutoGenerated() const;
@@ -638,7 +638,7 @@ struct BridgedFunction {
   SWIFT_IMPORT_UNSAFE BridgedFunction() {}
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE swift::SILFunction * _Nonnull getFunction() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getName() const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedLocation getLocation() const;
   BRIDGED_INLINE bool hasOwnership() const;
   BRIDGED_INLINE bool hasLoweredAddresses() const;
@@ -732,7 +732,7 @@ struct BridgedGlobalVar {
   BridgedGlobalVar(SwiftObject obj) : obj(obj) {}
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE swift::SILGlobalVariable * _Nonnull getGlobal() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedNullableVarDecl getDecl() const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedStringRef getName() const;
   BRIDGED_INLINE bool isLet() const;
   BRIDGED_INLINE void setLet(bool value) const;
@@ -849,7 +849,7 @@ struct BridgedInstruction {
 #endif
 
   BridgedInstruction(SwiftObject obj) : obj(obj) {}
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedInstruction getNext() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedInstruction getPrevious() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock getParent() const;
@@ -1111,7 +1111,7 @@ struct BridgedBasicBlock {
   }
 #endif
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedBasicBlock getNext() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedBasicBlock getPrevious() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getFunction() const;
@@ -1151,7 +1151,7 @@ struct BridgedSuccessorArray {
 struct BridgedVTableEntry {
   const swift::SILVTableEntry * _Nonnull entry;
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedFunction getImplementation() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedVTableEntry advanceBy(SwiftInt index) const;
 };
@@ -1164,7 +1164,7 @@ struct BridgedVTableEntryArray {
 struct BridgedVTable {
   const swift::SILVTable * _Nonnull vTable;
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedVTableEntryArray getEntries() const;
 };
 
@@ -1185,7 +1185,7 @@ struct BridgedWitnessTableEntry {
   }
 #endif
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   BRIDGED_INLINE Kind getKind() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedFunction getMethodFunction() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTableEntry advanceBy(SwiftInt index) const;
@@ -1199,7 +1199,7 @@ struct BridgedWitnessTableEntryArray {
 struct BridgedWitnessTable {
   const swift::SILWitnessTable * _Nonnull table;
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTableEntryArray getEntries() const;
 };
 
@@ -1210,7 +1210,7 @@ struct OptionalBridgedWitnessTable {
 struct BridgedDefaultWitnessTable {
   const swift::SILDefaultWitnessTable * _Nonnull table;
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getDebugDescription() const;
+  BridgedOwnedString getDebugDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedWitnessTableEntryArray getEntries() const;
 };
 

include/swift/SILOptimizer/OptimizerBridging.h

@@ -206,7 +206,7 @@ struct BridgedPassContext {
     Lowered
   };
 
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString getModuleDescription() const;
+  BridgedOwnedString getModuleDescription() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedChangeNotificationHandler asNotificationHandler() const;
   BRIDGED_INLINE void notifyDependencyOnBodyOf(BridgedFunction otherFunction) const;
   BRIDGED_INLINE SILStage getSILStage() const;
@@ -251,12 +251,12 @@ struct BridgedPassContext {
                                                                            BridgedFunction function) const;
   bool specializeClassMethodInst(BridgedInstruction cm) const;
   bool specializeAppliesInFunction(BridgedFunction function, bool isMandatory) const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString mangleOutlinedVariable(BridgedFunction function) const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString mangleAsyncRemoved(BridgedFunction function) const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString mangleWithDeadArgs(const SwiftInt * _Nullable deadArgs,
+  BridgedOwnedString mangleOutlinedVariable(BridgedFunction function) const;
+  BridgedOwnedString mangleAsyncRemoved(BridgedFunction function) const;
+  BridgedOwnedString mangleWithDeadArgs(const SwiftInt * _Nullable deadArgs,
                                                             SwiftInt numDeadArgs,
                                                             BridgedFunction function) const;
-  SWIFT_IMPORT_UNSAFE BridgedOwnedString mangleWithClosureArgs(BridgedValueArray closureArgs,
+  BridgedOwnedString mangleWithClosureArgs(BridgedValueArray closureArgs,
                                                                BridgedArrayRef closureArgIndices,
                                                                BridgedFunction applySiteCallee) const;