P0017R1: In C++1z, an aggregate class can have (public non-virtual) base classes; these are initialized as if they were data members.

llvm-svn: 262963

3 files changed, 59 insertions, 12 deletions

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 947b3d5b858..53131f7557f 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -1171,6 +1171,38 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
   unsigned NumInitElements = E->getNumInits();
   RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
 
+  // We'll need to enter cleanup scopes in case any of the element
+  // initializers throws an exception.
+  SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
+  llvm::Instruction *cleanupDominator = nullptr;
+
+  unsigned curInitIndex = 0;
+
+  // Emit initialization of base classes.
+  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
+    assert(E->getNumInits() >= CXXRD->getNumBases() &&
+           "missing initializer for base class");
+    for (auto &Base : CXXRD->bases()) {
+      assert(!Base.isVirtual() && "should not see vbases here");
+      auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
+      Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
+          Dest.getAddress(), CXXRD, BaseRD,
+          /*isBaseVirtual*/ false);
+      AggValueSlot AggSlot =
+        AggValueSlot::forAddr(V, Qualifiers(),
+                              AggValueSlot::IsDestructed,
+                              AggValueSlot::DoesNotNeedGCBarriers,
+                              AggValueSlot::IsNotAliased);
+      CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
+
+      if (QualType::DestructionKind dtorKind =
+              Base.getType().isDestructedType()) {
+        CGF.pushDestroy(dtorKind, V, Base.getType());
+        cleanups.push_back(CGF.EHStack.stable_begin());
+      }
+    }
+  }
+
   // Prepare a 'this' for CXXDefaultInitExprs.
   CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
 
@@ -1204,14 +1236,8 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
     return;
   }
 
-  // We'll need to enter cleanup scopes in case any of the member
-  // initializers throw an exception.
-  SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
-  llvm::Instruction *cleanupDominator = nullptr;
-
   // Here we iterate over the fields; this makes it simpler to both
   // default-initialize fields and skip over unnamed fields.
-  unsigned curInitIndex = 0;
   for (const auto *field : record->fields()) {
     // We're done once we hit the flexible array member.
     if (field->getType()->isIncompleteArrayType())
@@ -1317,6 +1343,10 @@ static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
       CharUnits NumNonZeroBytes = CharUnits::Zero();
       
       unsigned ILEElement = 0;
+      if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
+        for (auto &Base : CXXRD->bases())
+          NumNonZeroBytes +=
+              GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
       for (const auto *Field : SD->fields()) {
         // We're done once we hit the flexible array member or run out of
         // InitListExpr elements.
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 614b0769231..af370972491 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1011,15 +1011,18 @@ void CodeGenFunction::EmitNewArrayInitializer(
   if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
     if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
       if (RType->getDecl()->isStruct()) {
-        unsigned NumFields = 0;
+        unsigned NumElements = 0;
+        if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
+          NumElements = CXXRD->getNumBases();
         for (auto *Field : RType->getDecl()->fields())
           if (!Field->isUnnamedBitfield())
-            ++NumFields;
-        if (ILE->getNumInits() == NumFields)
+            ++NumElements;
+        // FIXME: Recurse into nested InitListExprs.
+        if (ILE->getNumInits() == NumElements)
           for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
             if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
-              --NumFields;
-        if (ILE->getNumInits() == NumFields && TryMemsetInitialization())
+              --NumElements;
+        if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
           return;
       }
     }
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 2aed3bb06d9..d64c5876ee2 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -368,7 +368,14 @@ bool ConstStructBuilder::Build(InitListExpr *ILE) {
 
   unsigned FieldNo = 0;
   unsigned ElementNo = 0;
-  
+
+  // Bail out if we have base classes. We could support these, but they only
+  // arise in C++1z where we will have already constant folded most interesting
+  // cases. FIXME: There are still a few more cases we can handle this way.
+  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+    if (CXXRD->getNumBases())
+      return false;
+
   for (RecordDecl::field_iterator Field = RD->field_begin(),
        FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
     // If this is a union, skip all the fields that aren't being initialized.
@@ -1124,6 +1131,13 @@ bool ConstStructBuilder::Build(ConstExprEmitter *Emitter,
   unsigned FieldNo = -1;
   unsigned ElementNo = 0;
 
+  // Bail out if we have base classes. We could support these, but they only
+  // arise in C++1z where we will have already constant folded most interesting
+  // cases. FIXME: There are still a few more cases we can handle this way.
+  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+    if (CXXRD->getNumBases())
+      return false;
+
   for (FieldDecl *Field : RD->fields()) {
     ++FieldNo;