For P0784R7: compute whether a variable has constant destruction if it

has a constexpr destructor.

For constexpr variables, reject if the variable does not have constant
destruction. In all cases, do not emit runtime calls to the destructor
for variables with constant destruction.

llvm-svn: 373159

1 files changed, 4 insertions, 11 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index a9e01619aab..5c0d52a1633 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -305,14 +305,6 @@ llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
   return Addr;
 }
 
-/// hasNontrivialDestruction - Determine whether a type's destruction is
-/// non-trivial. If so, and the variable uses static initialization, we must
-/// register its destructor to run on exit.
-static bool hasNontrivialDestruction(QualType T) {
-  CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
-  return RD && !RD->hasTrivialDestructor();
-}
-
 /// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
 /// global variable that has already been created for it.  If the initializer
 /// has a different type than GV does, this may free GV and return a different
@@ -372,7 +364,7 @@ CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
 
   emitter.finalize(GV);
 
-  if (hasNontrivialDestruction(D.getType()) && HaveInsertPoint()) {
+  if (D.needsDestruction(getContext()) && HaveInsertPoint()) {
     // We have a constant initializer, but a nontrivial destructor. We still
     // need to perform a guarded "initialization" in order to register the
     // destructor.
@@ -1994,7 +1986,7 @@ void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
   const VarDecl &D = *emission.Variable;
 
   // Check the type for a cleanup.
-  if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
+  if (QualType::DestructionKind dtorKind = D.needsDestruction(getContext()))
     emitAutoVarTypeCleanup(emission, dtorKind);
 
   // In GC mode, honor objc_precise_lifetime.
@@ -2404,7 +2396,8 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
     // cleanup.
     if (hasAggregateEvaluationKind(Ty) && !CurFuncIsThunk &&
         Ty->getAs<RecordType>()->getDecl()->isParamDestroyedInCallee()) {
-      if (QualType::DestructionKind DtorKind = Ty.isDestructedType()) {
+      if (QualType::DestructionKind DtorKind =
+              D.needsDestruction(getContext())) {
         assert((DtorKind == QualType::DK_cxx_destructor ||
                 DtorKind == QualType::DK_nontrivial_c_struct) &&
                "unexpected destructor type");