commit d35a454170da3da9c9bb0b5627f5796113195283
author Akira Hatanaka <ahatanaka@apple.com> Wed Nov 20 18:13:44 2019 -0800
committer ahatanak <ahatanaka@apple.com> Fri Mar 20 18:34:22 2020 -0700
tree 156aea7f797256e7aa2cb7c706abd4305a74c659
parent be10b7e43a3a10fbd3244f826591f3f65c0b7e21

[CodeGen] Emit destructor calls to destruct non-trivial C struct objects
returned by function calls or loaded from volatile objects

rdar://problem/51867864

Differential Revision: https://reviews.llvm.org/D66094

clang/lib/CodeGen/CGExprAgg.cpp

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 9881d28..df576de 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -249,7 +249,7 @@
     const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
   QualType RetTy = E->getType();
   bool RequiresDestruction =
-      Dest.isIgnored() &&
+      !Dest.isExternallyDestructed() &&
       RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
 
   // If it makes no observable difference, save a memcpy + temporary.
@@ -287,10 +287,8 @@
   }
 
   RValue Src =
-      EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused));
-
-  if (RequiresDestruction)
-    CGF.pushDestroy(RetTy.isDestructedType(), Src.getAggregateAddress(), RetTy);
+      EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused,
+                               Dest.isExternallyDestructed()));
 
   if (!UseTemp)
     return;
@@ -827,8 +825,19 @@
     // If we're loading from a volatile type, force the destination
     // into existence.
     if (E->getSubExpr()->getType().isVolatileQualified()) {
+      bool Destruct =
+          !Dest.isExternallyDestructed() &&
+          E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
+      if (Destruct)
+        Dest.setExternallyDestructed();
       EnsureDest(E->getType());
-      return Visit(E->getSubExpr());
+      Visit(E->getSubExpr());
+
+      if (Destruct)
+        CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
+                        E->getType());
+
+      return;
     }
 
     LLVM_FALLTHROUGH;