Revert 289252 (and follow-up 289285), it caused PR31374

llvm-svn: 289713

1 files changed, 24 insertions, 38 deletions

diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 752f419f64e..345e0a9216a 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -16,7 +16,6 @@
 #include "CGObjCRuntime.h"
 #include "CGRecordLayout.h"
 #include "CodeGenModule.h"
-#include "TargetInfo.h"
 #include "clang/AST/APValue.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/RecordLayout.h"
@@ -1263,10 +1262,6 @@ llvm::Constant *CodeGenModule::EmitConstantExpr(const Expr *E,
   return C;
 }
 
-llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
-  return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
-}
-
 llvm::Constant *CodeGenModule::EmitConstantValue(const APValue &Value,
                                                  QualType DestType,
                                                  CodeGenFunction *CGF) {
@@ -1298,7 +1293,6 @@ llvm::Constant *CodeGenModule::EmitConstantValue(const APValue &Value,
       llvm::ConstantInt::get(Int64Ty, Value.getLValueOffset().getQuantity());
 
     llvm::Constant *C = nullptr;
-
     if (APValue::LValueBase LVBase = Value.getLValueBase()) {
       // An array can be represented as an lvalue referring to the base.
       if (isa<llvm::ArrayType>(DestTy)) {
@@ -1329,9 +1323,7 @@ llvm::Constant *CodeGenModule::EmitConstantValue(const APValue &Value,
 
       // Convert to the appropriate type; this could be an lvalue for
       // an integer.
-      if (auto PT = dyn_cast<llvm::PointerType>(DestTy)) {
-        if (Value.isNullPointer())
-          return getNullPointer(PT, DestType);
+      if (isa<llvm::PointerType>(DestTy)) {
         // Convert the integer to a pointer-sized integer before converting it
         // to a pointer.
         C = llvm::ConstantExpr::getIntegerCast(
@@ -1518,7 +1510,7 @@ static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
                                                const CXXRecordDecl *base);
 
 static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
-                                        const RecordDecl *record,
+                                        const CXXRecordDecl *record,
                                         bool asCompleteObject) {
   const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
   llvm::StructType *structure =
@@ -1528,29 +1520,25 @@ static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
   unsigned numElements = structure->getNumElements();
   std::vector<llvm::Constant *> elements(numElements);
 
-  auto CXXR = dyn_cast<CXXRecordDecl>(record);
   // Fill in all the bases.
-  if (CXXR) {
-    for (const auto &I : CXXR->bases()) {
-      if (I.isVirtual()) {
-        // Ignore virtual bases; if we're laying out for a complete
-        // object, we'll lay these out later.
-        continue;
-      }
+  for (const auto &I : record->bases()) {
+    if (I.isVirtual()) {
+      // Ignore virtual bases; if we're laying out for a complete
+      // object, we'll lay these out later.
+      continue;
+    }
 
-      const CXXRecordDecl *base =
-        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
+    const CXXRecordDecl *base = 
+      cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
 
-      // Ignore empty bases.
-      if (base->isEmpty() ||
-          CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
-              .isZero())
-        continue;
-
-      unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
-      llvm::Type *baseType = structure->getElementType(fieldIndex);
-      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
-    }
+    // Ignore empty bases.
+    if (base->isEmpty() ||
+        CGM.getContext().getASTRecordLayout(base).getNonVirtualSize().isZero())
+      continue;
+    
+    unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
+    llvm::Type *baseType = structure->getElementType(fieldIndex);
+    elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
   }
 
   // Fill in all the fields.
@@ -1574,8 +1562,8 @@ static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
   }
 
   // Fill in the virtual bases, if we're working with the complete object.
-  if (CXXR && asCompleteObject) {
-    for (const auto &I : CXXR->vbases()) {
+  if (asCompleteObject) {
+    for (const auto &I : record->vbases()) {
       const CXXRecordDecl *base = 
         cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
 
@@ -1617,10 +1605,6 @@ static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
 }
 
 llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
-  if (T->getAs<PointerType>())
-    return getNullPointer(
-        cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
-
   if (getTypes().isZeroInitializable(T))
     return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
     
@@ -1636,8 +1620,10 @@ llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
     return llvm::ConstantArray::get(ATy, Array);
   }
 
-  if (const RecordType *RT = T->getAs<RecordType>())
-    return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
+  if (const RecordType *RT = T->getAs<RecordType>()) {
+    const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+    return ::EmitNullConstant(*this, RD, /*complete object*/ true);
+  }
 
   assert(T->isMemberDataPointerType() &&
          "Should only see pointers to data members here!");