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

6 files changed, 13 insertions, 23 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 7fa262ca6e8..0a0ba70d822 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3093,7 +3093,7 @@ void CodeGenFunction::EmitDelegateCallArg(CallArgList &args,
   // Deactivate the cleanup for the callee-destructed param that was pushed.
   if (hasAggregateEvaluationKind(type) && !CurFuncIsThunk &&
       type->getAs<RecordType>()->getDecl()->isParamDestroyedInCallee() &&
-      type.isDestructedType()) {
+      param->needsDestruction(getContext())) {
     EHScopeStack::stable_iterator cleanup =
         CalleeDestructedParamCleanups.lookup(cast<ParmVarDecl>(param));
     assert(cleanup.isValid() &&
diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index c8bb63c5c4b..76ab8852397 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -2083,7 +2083,7 @@ static bool canEmitDelegateCallArgs(CodeGenFunction &CGF,
   if (CGF.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
     // If the parameters are callee-cleanup, it's not safe to forward.
     for (auto *P : Ctor->parameters())
-      if (P->getType().isDestructedType())
+      if (P->needsDestruction(CGF.getContext()))
         return false;
 
     // Likewise if they're inalloca.
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");
diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index 7a0605b8450..a54e5dcfda2 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -73,16 +73,10 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
   // that isn't balanced out by a destructor call as intended by the
   // attribute. This also checks for -fno-c++-static-destructors and
   // bails even if the attribute is not present.
-  if (D.isNoDestroy(CGF.getContext()))
-    return;
-
-  CodeGenModule &CGM = CGF.CGM;
+  QualType::DestructionKind DtorKind = D.needsDestruction(CGF.getContext());
 
   // FIXME:  __attribute__((cleanup)) ?
 
-  QualType Type = D.getType();
-  QualType::DestructionKind DtorKind = Type.isDestructedType();
-
   switch (DtorKind) {
   case QualType::DK_none:
     return;
@@ -101,6 +95,9 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
   llvm::FunctionCallee Func;
   llvm::Constant *Argument;
 
+  CodeGenModule &CGM = CGF.CGM;
+  QualType Type = D.getType();
+
   // Special-case non-array C++ destructors, if they have the right signature.
   // Under some ABIs, destructors return this instead of void, and cannot be
   // passed directly to __cxa_atexit if the target does not allow this
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 486832bca5f..37e2533e976 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3809,9 +3809,9 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
     return;
 
   llvm::Constant *Init = nullptr;
-  CXXRecordDecl *RD = ASTTy->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
   bool NeedsGlobalCtor = false;
-  bool NeedsGlobalDtor = RD && !RD->hasTrivialDestructor();
+  bool NeedsGlobalDtor =
+      D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
 
   const VarDecl *InitDecl;
   const Expr *InitExpr = D->getAnyInitializer(InitDecl);
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 037185390c9..35e707243ea 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -350,7 +350,7 @@ public:
     // If we have the only definition, we don't need a thread wrapper if we
     // will emit the value as a constant.
     if (isUniqueGVALinkage(getContext().GetGVALinkageForVariable(VD)))
-      return !VD->getType().isDestructedType() && InitDecl->evaluateValue();
+      return !VD->needsDestruction(getContext()) && InitDecl->evaluateValue();
 
     // Otherwise, we need a thread wrapper unless we know that every
     // translation unit will emit the value as a constant. We rely on