diff --git a/clang/lib/CodeGen/ABIInfo.h b/clang/lib/CodeGen/ABIInfo.h
--- a/clang/lib/CodeGen/ABIInfo.h
+++ b/clang/lib/CodeGen/ABIInfo.h
@@ -120,6 +120,9 @@
     CodeGenTypes &CGT;
     bool SwiftErrorInRegister;
 
+    bool occupiesMoreThan(ArrayRef<llvm::Type *> scalarTypes,
+                          unsigned maxAllRegisters) const;
+
   public:
     SwiftABIInfo(CodeGen::CodeGenTypes &CGT, bool SwiftErrorInRegister)
         : CGT(CGT), SwiftErrorInRegister(SwiftErrorInRegister) {}
diff --git a/clang/lib/CodeGen/ABIInfo.cpp b/clang/lib/CodeGen/ABIInfo.cpp
new file mode 100644
--- /dev/null
+++ b/clang/lib/CodeGen/ABIInfo.cpp
@@ -0,0 +1,96 @@
+//===- ABIInfoImpl.cpp ----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ABIInfo.h"
+#include "ABIInfoImpl.h"
+
+using namespace clang;
+using namespace clang::CodeGen;
+
+ABIArgInfo ABIInfo::getNaturalAlignIndirect(QualType Ty, bool ByVal,
+                                            bool Realign,
+                                            llvm::Type *Padding) const {
+  return ABIArgInfo::getIndirect(getContext().getTypeAlignInChars(Ty), ByVal,
+                                 Realign, Padding);
+}
+
+ABIArgInfo ABIInfo::getNaturalAlignIndirectInReg(QualType Ty,
+                                                 bool Realign) const {
+  return ABIArgInfo::getIndirectInReg(getContext().getTypeAlignInChars(Ty),
+                                      /*ByVal*/ false, Realign);
+}
+
+Address ABIInfo::EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
+                             QualType Ty) const {
+  return Address::invalid();
+}
+
+bool ABIInfo::isPromotableIntegerTypeForABI(QualType Ty) const {
+  if (getContext().isPromotableIntegerType(Ty))
+    return true;
+
+  if (const auto *EIT = Ty->getAs<BitIntType>())
+    if (EIT->getNumBits() < getContext().getTypeSize(getContext().IntTy))
+      return true;
+
+  return false;
+}
+
+ABIInfo::~ABIInfo() = default;
+
+SwiftABIInfo::~SwiftABIInfo() = default;
+
+bool SwiftABIInfo::shouldPassIndirectly(ArrayRef<llvm::Type *> ComponentTys,
+                                        bool AsReturnValue) const {
+  return occupiesMoreThan(ComponentTys, /*total=*/4);
+}
+
+bool SwiftABIInfo::isLegalVectorType(CharUnits VectorSize, llvm::Type *EltTy,
+                                     unsigned NumElts) const {
+  // The default implementation of this assumes that the target guarantees
+  // 128-bit SIMD support but nothing more.
+  return (VectorSize.getQuantity() > 8 && VectorSize.getQuantity() <= 16);
+}
+
+CGCXXABI &ABIInfo::getCXXABI() const { return CGT.getCXXABI(); }
+
+ASTContext &ABIInfo::getContext() const { return CGT.getContext(); }
+
+llvm::LLVMContext &ABIInfo::getVMContext() const {
+  return CGT.getLLVMContext();
+}
+
+const llvm::DataLayout &ABIInfo::getDataLayout() const {
+  return CGT.getDataLayout();
+}
+
+const TargetInfo &ABIInfo::getTarget() const { return CGT.getTarget(); }
+
+const CodeGenOptions &ABIInfo::getCodeGenOpts() const {
+  return CGT.getCodeGenOpts();
+}
+
+bool ABIInfo::isAndroid() const { return getTarget().getTriple().isAndroid(); }
+
+bool ABIInfo::isOHOSFamily() const {
+  return getTarget().getTriple().isOHOSFamily();
+}
+
+bool ABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
+  return false;
+}
+
+bool ABIInfo::isHomogeneousAggregateSmallEnough(const Type *Base,
+                                                uint64_t Members) const {
+  return false;
+}
+
+bool ABIInfo::isZeroLengthBitfieldPermittedInHomogeneousAggregate() const {
+  // For compatibility with GCC, ignore empty bitfields in C++ mode.
+  return getContext().getLangOpts().CPlusPlus;
+}
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -124,7 +124,7 @@
 /// registers when expanded?
 ///
 /// This is intended to be the basis of a reasonable basic implementation
-/// of should{Pass,Return}IndirectlyForSwift.
+/// of should{Pass,Return}Indirectly.
 ///
 /// For most targets, a limit of four total registers is reasonable; this
 /// limits the amount of code required in order to move around the value
@@ -133,15 +133,14 @@
 /// immediately within the callee.  But some targets may need to further
 /// limit the register count due to an inability to support that many
 /// return registers.
-static bool occupiesMoreThan(CodeGenTypes &cgt,
-                             ArrayRef<llvm::Type*> scalarTypes,
-                             unsigned maxAllRegisters) {
+bool SwiftABIInfo::occupiesMoreThan(ArrayRef<llvm::Type *> scalarTypes,
+                                    unsigned maxAllRegisters) const {
   unsigned intCount = 0, fpCount = 0;
   for (llvm::Type *type : scalarTypes) {
     if (type->isPointerTy()) {
       intCount++;
     } else if (auto intTy = dyn_cast<llvm::IntegerType>(type)) {
-      auto ptrWidth = cgt.getTarget().getPointerWidth(LangAS::Default);
+      auto ptrWidth = CGT.getTarget().getPointerWidth(LangAS::Default);
       intCount += (intTy->getBitWidth() + ptrWidth - 1) / ptrWidth;
     } else {
       assert(type->isVectorTy() || type->isFloatingPointTy());
@@ -154,7 +153,7 @@
 
 bool SwiftABIInfo::shouldPassIndirectly(ArrayRef<llvm::Type *> ComponentTys,
                                         bool AsReturnValue) const {
-  return occupiesMoreThan(CGT, ComponentTys, /*total=*/4);
+  return occupiesMoreThan(ComponentTys, /*total=*/4);
 }
 
 bool SwiftABIInfo::isLegalVectorType(CharUnits VectorSize, llvm::Type *EltTy,
@@ -1245,7 +1244,7 @@
     // integer registers and three fp registers.  Oddly, it'll use up to
     // four vector registers for vectors, but those can overlap with the
     // scalar registers.
-    return occupiesMoreThan(CGT, ComponentTys, /*total=*/3);
+    return occupiesMoreThan(ComponentTys, /*total=*/3);
   }
 };