[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

Author: ahatanaka

clang/include/clang/AST/ASTImporter.h

@@ -16,6 +16,7 @@
 
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclarationName.h"
+#include "clang/AST/ExprCXX.h"
 #include "clang/AST/NestedNameSpecifier.h"
 #include "clang/AST/TemplateName.h"
 #include "clang/AST/Type.h"
@@ -349,6 +350,10 @@ class TypeSourceInfo;
       return ToOrErr.takeError();
     }
 
+    /// Import cleanup objects owned by ExprWithCleanup.
+    llvm::Expected<ExprWithCleanups::CleanupObject>
+    Import(ExprWithCleanups::CleanupObject From);
+
     /// Import the given type from the "from" context into the "to"
     /// context. A null type is imported as a null type (no error).
     ///

clang/include/clang/AST/ExprCXX.h

@@ -3321,13 +3321,15 @@ class DependentScopeDeclRefExpr final
 /// literal is the extent of the enclosing scope.
 class ExprWithCleanups final
     : public FullExpr,
-      private llvm::TrailingObjects<ExprWithCleanups, BlockDecl *> {
+      private llvm::TrailingObjects<
+          ExprWithCleanups,
+          llvm::PointerUnion<BlockDecl *, CompoundLiteralExpr *>> {
 public:
   /// The type of objects that are kept in the cleanup.
-  /// It's useful to remember the set of blocks;  we could also
-  /// remember the set of temporaries, but there's currently
-  /// no need.
-  using CleanupObject = BlockDecl *;
+  /// It's useful to remember the set of blocks and block-scoped compound
+  /// literals; we could also remember the set of temporaries, but there's
+  /// currently no need.
+  using CleanupObject = llvm::PointerUnion<BlockDecl *, CompoundLiteralExpr *>;
 
 private:
   friend class ASTStmtReader;

clang/include/clang/AST/TextNodeDumper.h

@@ -184,6 +184,7 @@ class TextNodeDumper
   void dumpBareDeclRef(const Decl *D);
   void dumpName(const NamedDecl *ND);
   void dumpAccessSpecifier(AccessSpecifier AS);
+  void dumpCleanupObject(const ExprWithCleanups::CleanupObject &C);
 
   void dumpDeclRef(const Decl *D, StringRef Label = {});
 

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -5543,6 +5543,8 @@ def note_enters_block_captures_weak : Note<
 def note_enters_block_captures_non_trivial_c_struct : Note<
   "jump enters lifetime of block which captures a C struct that is non-trivial "
   "to destroy">;
+def note_enters_compound_literal_scope : Note<
+  "jump enters lifetime of a compound literal that is non-trivial to destruct">;
 
 def note_exits_cleanup : Note<
   "jump exits scope of variable with __attribute__((cleanup))">;
@@ -5586,6 +5588,8 @@ def note_exits_block_captures_weak : Note<
 def note_exits_block_captures_non_trivial_c_struct : Note<
   "jump exits lifetime of block which captures a C struct that is non-trivial "
   "to destroy">;
+def note_exits_compound_literal_scope : Note<
+  "jump exits lifetime of a compound literal that is non-trivial to destruct">;
 
 def err_func_returning_qualified_void : ExtWarn<
   "function cannot return qualified void type %0">,

clang/include/clang/Sema/Sema.h

@@ -613,9 +613,8 @@ class Sema final {
   CleanupInfo Cleanup;
 
   /// ExprCleanupObjects - This is the stack of objects requiring
-  /// cleanup that are created by the current full expression.  The
-  /// element type here is ExprWithCleanups::Object.
-  SmallVector<BlockDecl*, 8> ExprCleanupObjects;
+  /// cleanup that are created by the current full expression.
+  SmallVector<ExprWithCleanups::CleanupObject, 8> ExprCleanupObjects;
 
   /// Store a set of either DeclRefExprs or MemberExprs that contain a reference
   /// to a variable (constant) that may or may not be odr-used in this Expr, and

clang/include/clang/Serialization/ASTBitCodes.h

@@ -1900,6 +1900,9 @@ namespace serialization {
       CTOR_INITIALIZER_INDIRECT_MEMBER
     };
 
+    /// Kinds of cleanup objects owned by ExprWithCleanups.
+    enum CleanupObjectKind { COK_Block, COK_CompoundLiteral };
+
     /// Describes the redeclarations of a declaration.
     struct LocalRedeclarationsInfo {
       // The ID of the first declaration

clang/lib/AST/ASTImporter.cpp

@@ -7910,6 +7910,18 @@ void ASTImporter::RegisterImportedDecl(Decl *FromD, Decl *ToD) {
   MapImported(FromD, ToD);
 }
 
+llvm::Expected<ExprWithCleanups::CleanupObject>
+ASTImporter::Import(ExprWithCleanups::CleanupObject From) {
+  if (auto *CLE = From.dyn_cast<CompoundLiteralExpr *>()) {
+    if (Expected<Expr *> R = Import(CLE))
+      return ExprWithCleanups::CleanupObject(cast<CompoundLiteralExpr>(*R));
+  }
+
+  // FIXME: Handle BlockDecl when we implement importing BlockExpr in
+  //        ASTNodeImporter.
+  return make_error<ImportError>(ImportError::UnsupportedConstruct);
+}
+
 Expected<QualType> ASTImporter::Import(QualType FromT) {
   if (FromT.isNull())
     return QualType{};

clang/lib/AST/JSONNodeDumper.cpp

@@ -1334,7 +1334,16 @@ void JSONNodeDumper::VisitExprWithCleanups(const ExprWithCleanups *EWC) {
   if (EWC->getNumObjects()) {
     JOS.attributeArray("cleanups", [this, EWC] {
       for (const ExprWithCleanups::CleanupObject &CO : EWC->getObjects())
-        JOS.value(createBareDeclRef(CO));
+        if (auto *BD = CO.dyn_cast<BlockDecl *>()) {
+          JOS.value(createBareDeclRef(BD));
+        } else if (auto *CLE = CO.dyn_cast<CompoundLiteralExpr *>()) {
+          llvm::json::Object Obj;
+          Obj["id"] = createPointerRepresentation(CLE);
+          Obj["kind"] = CLE->getStmtClassName();
+          JOS.value(std::move(Obj));
+        } else {
+          llvm_unreachable("unexpected cleanup object type");
+        }
     });
   }
 }

clang/lib/AST/TextNodeDumper.cpp

@@ -448,6 +448,23 @@ void TextNodeDumper::dumpAccessSpecifier(AccessSpecifier AS) {
   }
 }
 
+void TextNodeDumper::dumpCleanupObject(
+    const ExprWithCleanups::CleanupObject &C) {
+  if (auto *BD = C.dyn_cast<BlockDecl *>())
+    dumpDeclRef(BD, "cleanup");
+  else if (auto *CLE = C.dyn_cast<CompoundLiteralExpr *>())
+    AddChild([=] {
+      OS << "cleanup ";
+      {
+        ColorScope Color(OS, ShowColors, StmtColor);
+        OS << CLE->getStmtClassName();
+      }
+      dumpPointer(CLE);
+    });
+  else
+    llvm_unreachable("unexpected cleanup type");
+}
+
 void TextNodeDumper::dumpDeclRef(const Decl *D, StringRef Label) {
   if (!D)
     return;
@@ -950,7 +967,7 @@ void TextNodeDumper::VisitMaterializeTemporaryExpr(
 
 void TextNodeDumper::VisitExprWithCleanups(const ExprWithCleanups *Node) {
   for (unsigned i = 0, e = Node->getNumObjects(); i != e; ++i)
-    dumpDeclRef(Node->getObject(i), "cleanup");
+    dumpCleanupObject(Node->getObject(i));
 }
 
 void TextNodeDumper::VisitSizeOfPackExpr(const SizeOfPackExpr *Node) {

clang/lib/CodeGen/CGBlocks.cpp

@@ -860,13 +860,13 @@ static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) {
 }
 
 /// 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);
   }
 }