Merge commit '6419104d1878' from llvm.org/release/21.x into stable/21.x

Author: git apple-llvm automerger

clang/include/clang/Basic/LangOptions.def

@@ -515,6 +515,8 @@ LANGOPT(BoundsSafetyBringUpMissingChecks, 7, clang::LangOptions::getDefaultBound
         "Bring up new -fbounds-safety run-time checks")
 /* TO_UPSTREAM(BoundsSafety) OFF*/
 
+LANGOPT(EnableLifetimeSafety, 1, 0, NotCompatible, "Experimental lifetime safety analysis for C++")
+
 LANGOPT(PreserveVec3Type, 1, 0, NotCompatible, "Preserve 3-component vector type")
 
 #undef LANGOPT

clang/include/clang/Driver/Options.td

@@ -2018,6 +2018,14 @@ def fno_bounds_safety_bringup_missing_checks : Flag<["-"], "fno-bounds-safety-br
   Alias<fno_bounds_safety_bringup_missing_checks_EQ>, AliasArgs<["all"]>,
   HelpText<"Disable new -fbounds-safety run-time checks">;
 
+defm lifetime_safety : BoolFOption<
+  "experimental-lifetime-safety",
+  LangOpts<"EnableLifetimeSafety">, DefaultFalse,
+  PosFlag<SetTrue, [], [CC1Option], "Enable">,
+  NegFlag<SetFalse, [], [CC1Option], "Disable">,
+  BothFlags<[], [CC1Option],
+          " experimental lifetime safety for C++">>;
+
 defm addrsig : BoolFOption<"addrsig",
   CodeGenOpts<"Addrsig">, DefaultFalse,
   PosFlag<SetTrue, [], [ClangOption, CC1Option], "Emit">,

clang/lib/Sema/AnalysisBasedWarnings.cpp

@@ -3507,8 +3507,7 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
       .setAlwaysAdd(Stmt::UnaryOperatorClass);
   }
 
-  bool EnableLifetimeSafetyAnalysis = !Diags.isIgnored(
-      diag::warn_experimental_lifetime_safety_dummy_warning, D->getBeginLoc());
+  bool EnableLifetimeSafetyAnalysis = S.getLangOpts().EnableLifetimeSafety;
   // Install the logical handler.
   std::optional<LogicalErrorHandler> LEH;
   if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {

clang/test/Sema/warn-lifetime-safety-dataflow.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -mllvm -debug-only=LifetimeFacts,LifetimeDataflow -Wexperimental-lifetime-safety %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -fexperimental-lifetime-safety -mllvm -debug-only=LifetimeFacts,LifetimeDataflow -Wexperimental-lifetime-safety %s 2>&1 | FileCheck %s
 // REQUIRES: asserts
 
 struct MyObj {