commit 40568fec7e3eb51554cbdaf63a8044830be93fa4
author Akira Hatanaka <ahatanaka@apple.com> Tue Mar 10 14:06:25 2020 -0700
committer Akira Hatanaka <ahatanaka@apple.com> Tue Mar 10 14:08:28 2020 -0700
tree 020f52b714fddda7fe86b361c5f42d7de517d2db
parent ddfcda0256ca231499614742cce1b66db056dc2a

[CodeGen] Emit destructor calls to destruct compound literals

Fix a bug in IRGen where it wasn't destructing compound literals in C
that are ObjC pointer arrays or non-trivial structs. Also diagnose jumps
that enter or exit the lifetime of the compound literals.

rdar://problem/51867864

Differential Revision: https://reviews.llvm.org/D64464

clang/lib/CodeGen/CGBlocks.cpp

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 9ec3738..9097e51 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -860,13 +860,13 @@
 }
 
 /// Enter a full-expression with a non-trivial number of objects to
-/// clean up.  This is in this file because, at the moment, the only
-/// kind of cleanup object is a BlockDecl*.
+/// clean up.
 void CodeGenFunction::enterNonTrivialFullExpression(const FullExpr *E) {
   if (const auto EWC = dyn_cast<ExprWithCleanups>(E)) {
     assert(EWC->getNumObjects() != 0);
     for (const ExprWithCleanups::CleanupObject &C : EWC->getObjects())
-      enterBlockScope(*this, C);
+      if (auto *BD = C.dyn_cast<BlockDecl *>())
+        enterBlockScope(*this, BD);
   }
 }
 

clang/lib/CodeGen/CGExpr.cpp

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 356d768..a3399af 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -4268,6 +4268,14 @@
   EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
                    /*Init*/ true);
 
+  // Block-scope compound literals are destroyed at the end of the enclosing
+  // scope in C.
+  if (!getLangOpts().CPlusPlus)
+    if (QualType::DestructionKind DtorKind = E->getType().isDestructedType())
+      pushLifetimeExtendedDestroy(getCleanupKind(DtorKind), DeclPtr,
+                                  E->getType(), getDestroyer(DtorKind),
+                                  DtorKind & EHCleanup);
+
   return Result;
 }
 

clang/lib/CodeGen/CGExprAgg.cpp

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 8de609a..9881d28 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -659,7 +659,21 @@
   }
 
   AggValueSlot Slot = EnsureSlot(E->getType());
+
+  // Block-scope compound literals are destroyed at the end of the enclosing
+  // scope in C.
+  bool Destruct =
+      !CGF.getLangOpts().CPlusPlus && !Slot.isExternallyDestructed();
+  if (Destruct)
+    Slot.setExternallyDestructed();
+
   CGF.EmitAggExpr(E->getInitializer(), Slot);
+
+  if (Destruct)
+    if (QualType::DestructionKind DtorKind = E->getType().isDestructedType())
+      CGF.pushLifetimeExtendedDestroy(
+          CGF.getCleanupKind(DtorKind), Slot.getAddress(), E->getType(),
+          CGF.getDestroyer(DtorKind), DtorKind & EHCleanup);
 }
 
 /// Attempt to look through various unimportant expressions to find a

clang/lib/CodeGen/CGExprScalar.cpp

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 8d9bf17..a0d1fe2 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -556,6 +556,11 @@
   Value *VisitMemberExpr(MemberExpr *E);
   Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
   Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
+    // Strictly speaking, we shouldn't be calling EmitLoadOfLValue, which
+    // transitively calls EmitCompoundLiteralLValue, here in C++ since compound
+    // literals aren't l-values in C++. We do so simply because that's the
+    // cleanest way to handle compound literals in C++.
+    // See the discussion here: https://reviews.llvm.org/D64464
     return EmitLoadOfLValue(E);
   }