[DebugInfo] Add kind of ImplicitParamDecl for emission of FlagObjectPointer.

Summary:
If the first parameter of the function is the ImplicitParamDecl, codegen
automatically marks it as an implicit argument with `this` or `self`
pointer. Added internal kind of the ImplicitParamDecl to separate
'this', 'self', 'vtt' and other implicit parameters from other kind of
parameters.

Reviewers: rjmccall, aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D33735

llvm-svn: 305075

19 files changed, 202 insertions, 192 deletions

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 847638b7bbe..493cb6df8b8 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -2462,10 +2462,9 @@ Decl *ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
     return nullptr;
 
   // Create the imported parameter.
-  ImplicitParamDecl *ToParm
-    = ImplicitParamDecl::Create(Importer.getToContext(), DC,
-                                Loc, Name.getAsIdentifierInfo(),
-                                T);
+  auto *ToParm = ImplicitParamDecl::Create(Importer.getToContext(), DC, Loc,
+                                           Name.getAsIdentifierInfo(), T,
+                                           D->getParameterKind());
   return Importer.Imported(D, ToParm);
 }
 
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index eeffc50f29e..9862f4f2647 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -4106,15 +4106,19 @@ void ImplicitParamDecl::anchor() { }
 
 ImplicitParamDecl *ImplicitParamDecl::Create(ASTContext &C, DeclContext *DC,
                                              SourceLocation IdLoc,
-                                             IdentifierInfo *Id,
-                                             QualType Type) {
-  return new (C, DC) ImplicitParamDecl(C, DC, IdLoc, Id, Type);
+                                             IdentifierInfo *Id, QualType Type,
+                                             ImplicitParamKind ParamKind) {
+  return new (C, DC) ImplicitParamDecl(C, DC, IdLoc, Id, Type, ParamKind);
+}
+
+ImplicitParamDecl *ImplicitParamDecl::Create(ASTContext &C, QualType Type,
+                                             ImplicitParamKind ParamKind) {
+  return new (C, nullptr) ImplicitParamDecl(C, Type, ParamKind);
 }
 
 ImplicitParamDecl *ImplicitParamDecl::CreateDeserialized(ASTContext &C,
                                                          unsigned ID) {
-  return new (C, ID) ImplicitParamDecl(C, nullptr, SourceLocation(), nullptr,
-                                       QualType());
+  return new (C, ID) ImplicitParamDecl(C, QualType(), ImplicitParamKind::Other);
 }
 
 FunctionDecl *FunctionDecl::Create(ASTContext &C, DeclContext *DC,
diff --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index a12a38033c4..a0ec0c2b251 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -1070,20 +1070,20 @@ void ObjCMethodDecl::createImplicitParams(ASTContext &Context,
   bool selfIsPseudoStrong, selfIsConsumed;
   QualType selfTy =
     getSelfType(Context, OID, selfIsPseudoStrong, selfIsConsumed);
-  ImplicitParamDecl *self
-    = ImplicitParamDecl::Create(Context, this, SourceLocation(),
-                                &Context.Idents.get("self"), selfTy);
-  setSelfDecl(self);
+  auto *Self = ImplicitParamDecl::Create(Context, this, SourceLocation(),
+                                         &Context.Idents.get("self"), selfTy,
+                                         ImplicitParamDecl::ObjCSelf);
+  setSelfDecl(Self);
 
   if (selfIsConsumed)
-    self->addAttr(NSConsumedAttr::CreateImplicit(Context));
+    Self->addAttr(NSConsumedAttr::CreateImplicit(Context));
 
   if (selfIsPseudoStrong)
-    self->setARCPseudoStrong(true);
+    Self->setARCPseudoStrong(true);
 
-  setCmdDecl(ImplicitParamDecl::Create(Context, this, SourceLocation(),
-                                       &Context.Idents.get("_cmd"),
-                                       Context.getObjCSelType()));
+  setCmdDecl(ImplicitParamDecl::Create(
+      Context, this, SourceLocation(), &Context.Idents.get("_cmd"),
+      Context.getObjCSelType(), ImplicitParamDecl::ObjCCmd));
 }
 
 ObjCInterfaceDecl *ObjCMethodDecl::getClassInterface() {
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 2e423b25f0f..528a2b33acf 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -903,9 +903,8 @@ llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
     } else {
       // Fake up a new variable so that EmitScalarInit doesn't think
       // we're referring to the variable in its own initializer.
-      ImplicitParamDecl blockFieldPseudoVar(getContext(), /*DC*/ nullptr,
-                                            SourceLocation(), /*name*/ nullptr,
-                                            type);
+      ImplicitParamDecl BlockFieldPseudoVar(getContext(), type,
+                                            ImplicitParamDecl::Other);
 
       // We use one of these or the other depending on whether the
       // reference is nested.
@@ -919,7 +918,7 @@ llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
       // attributed to a reasonable location - otherwise it may be attributed to
       // locations of subexpressions in the initialization.
       LValueBaseInfo BaseInfo(AlignmentSource::Decl, false);
-      EmitExprAsInit(&l2r, &blockFieldPseudoVar,
+      EmitExprAsInit(&l2r, &BlockFieldPseudoVar,
                      MakeAddrLValue(blockField, type, BaseInfo),
                      /*captured by init*/ false);
     }
@@ -1264,9 +1263,10 @@ CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
 
   IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
 
-  ImplicitParamDecl selfDecl(getContext(), const_cast<BlockDecl*>(blockDecl),
-                             SourceLocation(), II, selfTy);
-  args.push_back(&selfDecl);
+  ImplicitParamDecl SelfDecl(getContext(), const_cast<BlockDecl *>(blockDecl),
+                             SourceLocation(), II, selfTy,
+                             ImplicitParamDecl::ObjCSelf);
+  args.push_back(&SelfDecl);
 
   // Now add the rest of the parameters.
   args.append(blockDecl->param_begin(), blockDecl->param_end());
@@ -1499,12 +1499,12 @@ CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
   ASTContext &C = getContext();
 
   FunctionArgList args;
-  ImplicitParamDecl dstDecl(getContext(), nullptr, SourceLocation(), nullptr,
-                            C.VoidPtrTy);
-  args.push_back(&dstDecl);
-  ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr,
-                            C.VoidPtrTy);
-  args.push_back(&srcDecl);
+  ImplicitParamDecl DstDecl(getContext(), C.VoidPtrTy,
+                            ImplicitParamDecl::Other);
+  args.push_back(&DstDecl);
+  ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
+                            ImplicitParamDecl::Other);
+  args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
@@ -1536,11 +1536,11 @@ CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
   auto AL = ApplyDebugLocation::CreateArtificial(*this);
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
-  Address src = GetAddrOfLocalVar(&srcDecl);
+  Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block.source");
 
-  Address dst = GetAddrOfLocalVar(&dstDecl);
+  Address dst = GetAddrOfLocalVar(&DstDecl);
   dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign);
   dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
 
@@ -1676,9 +1676,9 @@ CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
   ASTContext &C = getContext();
 
   FunctionArgList args;
-  ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr,
-                            C.VoidPtrTy);
-  args.push_back(&srcDecl);
+  ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
+                            ImplicitParamDecl::Other);
+  args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
@@ -1709,7 +1709,7 @@ CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
-  Address src = GetAddrOfLocalVar(&srcDecl);
+  Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block");
 
@@ -1918,13 +1918,13 @@ generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
   QualType R = Context.VoidTy;
 
   FunctionArgList args;
-  ImplicitParamDecl dst(CGF.getContext(), nullptr, SourceLocation(), nullptr,
-                        Context.VoidPtrTy);
-  args.push_back(&dst);
+  ImplicitParamDecl Dst(CGF.getContext(), Context.VoidPtrTy,
+                        ImplicitParamDecl::Other);
+  args.push_back(&Dst);
 
-  ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr,
-                        Context.VoidPtrTy);
-  args.push_back(&src);
+  ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy,
+                        ImplicitParamDecl::Other);
+  args.push_back(&Src);
 
   const CGFunctionInfo &FI =
     CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
@@ -1955,7 +1955,7 @@ generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
     llvm::Type *byrefPtrType = byrefInfo.Type->getPointerTo(0);
 
     // dst->x
-    Address destField = CGF.GetAddrOfLocalVar(&dst);
+    Address destField = CGF.GetAddrOfLocalVar(&Dst);
     destField = Address(CGF.Builder.CreateLoad(destField),
                         byrefInfo.ByrefAlignment);
     destField = CGF.Builder.CreateBitCast(destField, byrefPtrType);
@@ -1963,7 +1963,7 @@ generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
                                           "dest-object");
 
     // src->x
-    Address srcField = CGF.GetAddrOfLocalVar(&src);
+    Address srcField = CGF.GetAddrOfLocalVar(&Src);
     srcField = Address(CGF.Builder.CreateLoad(srcField),
                        byrefInfo.ByrefAlignment);
     srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType);
@@ -1995,9 +1995,9 @@ generateByrefDisposeHelper(CodeGenFunction &CGF,
   QualType R = Context.VoidTy;
 
   FunctionArgList args;
-  ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr,
-                        Context.VoidPtrTy);
-  args.push_back(&src);
+  ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy,
+                        ImplicitParamDecl::Other);
+  args.push_back(&Src);
 
   const CGFunctionInfo &FI =
     CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
@@ -2026,7 +2026,7 @@ generateByrefDisposeHelper(CodeGenFunction &CGF,
   CGF.StartFunction(FD, R, Fn, FI, args);
 
   if (generator.needsDispose()) {
-    Address addr = CGF.GetAddrOfLocalVar(&src);
+    Address addr = CGF.GetAddrOfLocalVar(&Src);
     addr = Address(CGF.Builder.CreateLoad(addr), byrefInfo.ByrefAlignment);
     auto byrefPtrType = byrefInfo.Type->getPointerTo(0);
     addr = CGF.Builder.CreateBitCast(addr, byrefPtrType);
diff --git a/clang/lib/CodeGen/CGCXXABI.cpp b/clang/lib/CodeGen/CGCXXABI.cpp
index df75a7d7ffd..e29e525edd2 100644
--- a/clang/lib/CodeGen/CGCXXABI.cpp
+++ b/clang/lib/CodeGen/CGCXXABI.cpp
@@ -159,10 +159,10 @@ void CGCXXABI::buildThisParam(CodeGenFunction &CGF, FunctionArgList &params) {
 
   // FIXME: I'm not entirely sure I like using a fake decl just for code
   // generation. Maybe we can come up with a better way?
-  ImplicitParamDecl *ThisDecl
-    = ImplicitParamDecl::Create(CGM.getContext(), nullptr, MD->getLocation(),
-                                &CGM.getContext().Idents.get("this"),
-                                MD->getThisType(CGM.getContext()));
+  auto *ThisDecl = ImplicitParamDecl::Create(
+      CGM.getContext(), nullptr, MD->getLocation(),
+      &CGM.getContext().Idents.get("this"), MD->getThisType(CGM.getContext()),
+      ImplicitParamDecl::CXXThis);
   params.push_back(ThisDecl);
   CGF.CXXABIThisDecl = ThisDecl;
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 02db79159b5..42b896b1180 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3466,13 +3466,13 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
   unsigned AddressSpace = CGM.getContext().getTargetAddressSpace(VD->getType());
   AppendAddressSpaceXDeref(AddressSpace, Expr);
 
-  // If this is the first argument and it is implicit then
-  // give it an object pointer flag.
-  // FIXME: There has to be a better way to do this, but for static
-  // functions there won't be an implicit param at arg1 and
-  // otherwise it is 'self' or 'this'.
-  if (isa<ImplicitParamDecl>(VD) && ArgNo && *ArgNo == 1)
-  Flags |= llvm::DINode::FlagObjectPointer;
+  // If this is implicit parameter and has IPK_CXXThis or IPK_ObjCSelf attribute
+  // then give it an object pointer flag.
+  if (const auto *IPD = dyn_cast<ImplicitParamDecl>(VD)) {
+    if (IPD->getParameterKind() == ImplicitParamDecl::CXXThis ||
+        IPD->getParameterKind() == ImplicitParamDecl::ObjCSelf)
+      Flags |= llvm::DINode::FlagObjectPointer;
+  }
 
   // Note: Older versions of clang used to emit byval references with an extra
   // DW_OP_deref, because they referenced the IR arg directly instead of
@@ -3583,8 +3583,9 @@ void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
 
   // Self is passed along as an implicit non-arg variable in a
   // block. Mark it as the object pointer.
-  if (isa<ImplicitParamDecl>(VD) && VD->getName() == "self")
-    Ty = CreateSelfType(VD->getType(), Ty);
+  if (const auto *IPD = dyn_cast<ImplicitParamDecl>(VD))
+    if (IPD->getParameterKind() == ImplicitParamDecl::ObjCSelf)
+      Ty = CreateSelfType(VD->getType(), Ty);
 
   // Get location information.
   unsigned Line = getLineNumber(VD->getLocation());
diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index ff766e6b3b9..d8768bee2cd 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -603,9 +603,9 @@ llvm::Function *CodeGenFunction::generateDestroyHelper(
     Address addr, QualType type, Destroyer *destroyer,
     bool useEHCleanupForArray, const VarDecl *VD) {
   FunctionArgList args;
-  ImplicitParamDecl dst(getContext(), nullptr, SourceLocation(), nullptr,
-                        getContext().VoidPtrTy);
-  args.push_back(&dst);
+  ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
+                        ImplicitParamDecl::Other);
+  args.push_back(&Dst);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index e65fa863fe3..40ae0921098 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -1649,18 +1649,19 @@ void CodeGenFunction::startOutlinedSEHHelper(CodeGenFunction &ParentCGF,
     // parameters. Win32 filters take no parameters.
     if (IsFilter) {
       Args.push_back(ImplicitParamDecl::Create(
-          getContext(), nullptr, StartLoc,
+          getContext(), /*DC=*/nullptr, StartLoc,
           &getContext().Idents.get("exception_pointers"),
-          getContext().VoidPtrTy));
+          getContext().VoidPtrTy, ImplicitParamDecl::Other));
     } else {
       Args.push_back(ImplicitParamDecl::Create(
-          getContext(), nullptr, StartLoc,
+          getContext(), /*DC=*/nullptr, StartLoc,
           &getContext().Idents.get("abnormal_termination"),
-          getContext().UnsignedCharTy));
+          getContext().UnsignedCharTy, ImplicitParamDecl::Other));
     }
     Args.push_back(ImplicitParamDecl::Create(
-        getContext(), nullptr, StartLoc,
-        &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy));
+        getContext(), /*DC=*/nullptr, StartLoc,
+        &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
+        ImplicitParamDecl::Other));
   }
 
   QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 2aa04587921..9f800a75b5b 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2847,10 +2847,10 @@ void CodeGenFunction::EmitCfiCheckStub() {
 void CodeGenFunction::EmitCfiCheckFail() {
   SanitizerScope SanScope(this);
   FunctionArgList Args;
-  ImplicitParamDecl ArgData(getContext(), nullptr, SourceLocation(), nullptr,
-                            getContext().VoidPtrTy);
-  ImplicitParamDecl ArgAddr(getContext(), nullptr, SourceLocation(), nullptr,
-                            getContext().VoidPtrTy);
+  ImplicitParamDecl ArgData(getContext(), getContext().VoidPtrTy,
+                            ImplicitParamDecl::Other);
+  ImplicitParamDecl ArgAddr(getContext(), getContext().VoidPtrTy,
+                            ImplicitParamDecl::Other);
   Args.push_back(&ArgData);
   Args.push_back(&ArgAddr);
 
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 82052012176..90fcad26141 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -3246,10 +3246,12 @@ CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
   SrcTy = C.getPointerType(SrcTy);
   
   FunctionArgList args;
-  ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
-  args.push_back(&dstDecl);
-  ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
-  args.push_back(&srcDecl);
+  ImplicitParamDecl DstDecl(getContext(), FD, SourceLocation(), /*Id=*/nullptr,
+                            DestTy, ImplicitParamDecl::Other);
+  args.push_back(&DstDecl);
+  ImplicitParamDecl SrcDecl(getContext(), FD, SourceLocation(), /*Id=*/nullptr,
+                            SrcTy, ImplicitParamDecl::Other);
+  args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
@@ -3265,12 +3267,12 @@ CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
 
   StartFunction(FD, C.VoidTy, Fn, FI, args);
   
-  DeclRefExpr DstExpr(&dstDecl, false, DestTy,
+  DeclRefExpr DstExpr(&DstDecl, false, DestTy,
                       VK_RValue, SourceLocation());
   UnaryOperator DST(&DstExpr, UO_Deref, DestTy->getPointeeType(),
                     VK_LValue, OK_Ordinary, SourceLocation());
   
-  DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
+  DeclRefExpr SrcExpr(&SrcDecl, false, SrcTy,
                       VK_RValue, SourceLocation());
   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
                     VK_LValue, OK_Ordinary, SourceLocation());
@@ -3327,10 +3329,12 @@ CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
   SrcTy = C.getPointerType(SrcTy);
   
   FunctionArgList args;
-  ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
-  args.push_back(&dstDecl);
-  ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
-  args.push_back(&srcDecl);
+  ImplicitParamDecl DstDecl(getContext(), FD, SourceLocation(), /*Id=*/nullptr,
+                            DestTy, ImplicitParamDecl::Other);
+  args.push_back(&DstDecl);
+  ImplicitParamDecl SrcDecl(getContext(), FD, SourceLocation(), /*Id=*/nullptr,
+                            SrcTy, ImplicitParamDecl::Other);
+  args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
@@ -3345,7 +3349,7 @@ CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
 
   StartFunction(FD, C.VoidTy, Fn, FI, args);
   
-  DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
+  DeclRefExpr SrcExpr(&SrcDecl, false, SrcTy,
                       VK_RValue, SourceLocation());
   
   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
@@ -3371,7 +3375,7 @@ CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
                              CXXConstExpr->getConstructionKind(),
                              SourceRange());
   
-  DeclRefExpr DstExpr(&dstDecl, false, DestTy,
+  DeclRefExpr DstExpr(&DstDecl, false, DestTy,
                       VK_RValue, SourceLocation());
   
   RValue DV = EmitAnyExpr(&DstExpr);
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index 63300e25d37..468838e56e3 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -747,9 +747,9 @@ emitCombinerOrInitializer(CodeGenModule &CGM, QualType Ty,
   QualType PtrTy = C.getPointerType(Ty).withRestrict();
   FunctionArgList Args;
   ImplicitParamDecl OmpOutParm(C, /*DC=*/nullptr, Out->getLocation(),
-                               /*Id=*/nullptr, PtrTy);
+                               /*Id=*/nullptr, PtrTy, ImplicitParamDecl::Other);
   ImplicitParamDecl OmpInParm(C, /*DC=*/nullptr, In->getLocation(),
-                              /*Id=*/nullptr, PtrTy);
+                              /*Id=*/nullptr, PtrTy, ImplicitParamDecl::Other);
   Args.push_back(&OmpOutParm);
   Args.push_back(&OmpInParm);
   auto &FnInfo =
@@ -1808,8 +1808,8 @@ llvm::Function *CGOpenMPRuntime::emitThreadPrivateVarDefinition(
       // threadprivate copy of the variable VD
       CodeGenFunction CtorCGF(CGM);
       FunctionArgList Args;
-      ImplicitParamDecl Dst(CGM.getContext(), /*DC=*/nullptr, SourceLocation(),
-                            /*Id=*/nullptr, CGM.getContext().VoidPtrTy);
+      ImplicitParamDecl Dst(CGM.getContext(), CGM.getContext().VoidPtrTy,
+                            ImplicitParamDecl::Other);
       Args.push_back(&Dst);
 
       auto &FI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(
@@ -1839,8 +1839,8 @@ llvm::Function *CGOpenMPRuntime::emitThreadPrivateVarDefinition(
       // of the variable VD
       CodeGenFunction DtorCGF(CGM);
       FunctionArgList Args;
-      ImplicitParamDecl Dst(CGM.getContext(), /*DC=*/nullptr, SourceLocation(),
-                            /*Id=*/nullptr, CGM.getContext().VoidPtrTy);
+      ImplicitParamDecl Dst(CGM.getContext(), CGM.getContext().VoidPtrTy,
+                            ImplicitParamDecl::Other);
       Args.push_back(&Dst);
 
       auto &FI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(
@@ -2191,10 +2191,8 @@ static llvm::Value *emitCopyprivateCopyFunction(
   auto &C = CGM.getContext();
   // void copy_func(void *LHSArg, void *RHSArg);
   FunctionArgList Args;
-  ImplicitParamDecl LHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
-                           C.VoidPtrTy);
-  ImplicitParamDecl RHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
-                           C.VoidPtrTy);
+  ImplicitParamDecl LHSArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
+  ImplicitParamDecl RHSArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   Args.push_back(&LHSArg);
   Args.push_back(&RHSArg);
   auto &CGFI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, Args);
@@ -2785,8 +2783,7 @@ createOffloadingBinaryDescriptorFunction(CodeGenModule &CGM, StringRef Name,
                                          const RegionCodeGenTy &Codegen) {
   auto &C = CGM.getContext();
   FunctionArgList Args;
-  ImplicitParamDecl DummyPtr(C, /*DC=*/nullptr, SourceLocation(),
-                             /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl DummyPtr(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   Args.push_back(&DummyPtr);
 
   CodeGenFunction CGF(CGM);
@@ -2889,7 +2886,7 @@ CGOpenMPRuntime::createOffloadingBinaryDescriptorRegistration() {
   // descriptor, so we can reuse the logic that emits Ctors and Dtors.
   auto *IdentInfo = &C.Idents.get(".omp_offloading.reg_unreg_var");
   ImplicitParamDecl RegUnregVar(C, C.getTranslationUnitDecl(), SourceLocation(),
-                                IdentInfo, C.CharTy);
+                                IdentInfo, C.CharTy, ImplicitParamDecl::Other);
 
   auto *UnRegFn = createOffloadingBinaryDescriptorFunction(
       CGM, ".omp_offloading.descriptor_unreg",
@@ -3319,10 +3316,11 @@ emitProxyTaskFunction(CodeGenModule &CGM, SourceLocation Loc,
                       llvm::Value *TaskPrivatesMap) {
   auto &C = CGM.getContext();
   FunctionArgList Args;
-  ImplicitParamDecl GtidArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr, KmpInt32Ty);
-  ImplicitParamDecl TaskTypeArg(C, /*DC=*/nullptr, Loc,
-                                /*Id=*/nullptr,
-                                KmpTaskTWithPrivatesPtrQTy.withRestrict());
+  ImplicitParamDecl GtidArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr, KmpInt32Ty,
+                            ImplicitParamDecl::Other);
+  ImplicitParamDecl TaskTypeArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+                                KmpTaskTWithPrivatesPtrQTy.withRestrict(),
+                                ImplicitParamDecl::Other);
   Args.push_back(&GtidArg);
   Args.push_back(&TaskTypeArg);
   auto &TaskEntryFnInfo =
@@ -3413,10 +3411,11 @@ static llvm::Value *emitDestructorsFunction(CodeGenModule &CGM,
                                             QualType KmpTaskTWithPrivatesQTy) {
   auto &C = CGM.getContext();
   FunctionArgList Args;
-  ImplicitParamDecl GtidArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr, KmpInt32Ty);
-  ImplicitParamDecl TaskTypeArg(C, /*DC=*/nullptr, Loc,
-                                /*Id=*/nullptr,
-                                KmpTaskTWithPrivatesPtrQTy.withRestrict());
+  ImplicitParamDecl GtidArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr, KmpInt32Ty,
+                            ImplicitParamDecl::Other);
+  ImplicitParamDecl TaskTypeArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+                                KmpTaskTWithPrivatesPtrQTy.withRestrict(),
+                                ImplicitParamDecl::Other);
   Args.push_back(&GtidArg);
   Args.push_back(&TaskTypeArg);
   FunctionType::ExtInfo Info;
@@ -3472,36 +3471,40 @@ emitTaskPrivateMappingFunction(CodeGenModule &CGM, SourceLocation Loc,
   FunctionArgList Args;
   ImplicitParamDecl TaskPrivatesArg(
       C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
-      C.getPointerType(PrivatesQTy).withConst().withRestrict());
+      C.getPointerType(PrivatesQTy).withConst().withRestrict(),
+      ImplicitParamDecl::Other);
   Args.push_back(&TaskPrivatesArg);
   llvm::DenseMap<const VarDecl *, unsigned> PrivateVarsPos;
   unsigned Counter = 1;
   for (auto *E: PrivateVars) {
     Args.push_back(ImplicitParamDecl::Create(
-        C, /*DC=*/nullptr, Loc,
-        /*Id=*/nullptr, C.getPointerType(C.getPointerType(E->getType()))
-                            .withConst()
-                            .withRestrict()));
+        C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+        C.getPointerType(C.getPointerType(E->getType()))
+            .withConst()
+            .withRestrict(),
+        ImplicitParamDecl::Other));
     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
     PrivateVarsPos[VD] = Counter;
     ++Counter;
   }
   for (auto *E : FirstprivateVars) {
     Args.push_back(ImplicitParamDecl::Create(
-        C, /*DC=*/nullptr, Loc,
-        /*Id=*/nullptr, C.getPointerType(C.getPointerType(E->getType()))
-                            .withConst()
-                            .withRestrict()));
+        C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+        C.getPointerType(C.getPointerType(E->getType()))
+            .withConst()
+            .withRestrict(),
+        ImplicitParamDecl::Other));
     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
     PrivateVarsPos[VD] = Counter;
     ++Counter;
   }
   for (auto *E: LastprivateVars) {
     Args.push_back(ImplicitParamDecl::Create(
-        C, /*DC=*/nullptr, Loc,
-        /*Id=*/nullptr, C.getPointerType(C.getPointerType(E->getType()))
-                            .withConst()
-                            .withRestrict()));
+        C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+        C.getPointerType(C.getPointerType(E->getType()))
+            .withConst()
+            .withRestrict(),
+        ImplicitParamDecl::Other));
     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
     PrivateVarsPos[VD] = Counter;
     ++Counter;
@@ -3661,12 +3664,14 @@ emitTaskDupFunction(CodeGenModule &CGM, SourceLocation Loc,
                     ArrayRef<PrivateDataTy> Privates, bool WithLastIter) {
   auto &C = CGM.getContext();
   FunctionArgList Args;
-  ImplicitParamDecl DstArg(C, /*DC=*/nullptr, Loc,
-                           /*Id=*/nullptr, KmpTaskTWithPrivatesPtrQTy);
-  ImplicitParamDecl SrcArg(C, /*DC=*/nullptr, Loc,
-                           /*Id=*/nullptr, KmpTaskTWithPrivatesPtrQTy);
-  ImplicitParamDecl LastprivArg(C, /*DC=*/nullptr, Loc,
-                                /*Id=*/nullptr, C.IntTy);
+  ImplicitParamDecl DstArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+                           KmpTaskTWithPrivatesPtrQTy,
+                           ImplicitParamDecl::Other);
+  ImplicitParamDecl SrcArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr,
+                           KmpTaskTWithPrivatesPtrQTy,
+                           ImplicitParamDecl::Other);
+  ImplicitParamDecl LastprivArg(C, /*DC=*/nullptr, Loc, /*Id=*/nullptr, C.IntTy,
+                                ImplicitParamDecl::Other);
   Args.push_back(&DstArg);
   Args.push_back(&SrcArg);
   Args.push_back(&LastprivArg);
@@ -4278,10 +4283,8 @@ llvm::Value *CGOpenMPRuntime::emitReductionFunction(
 
   // void reduction_func(void *LHSArg, void *RHSArg);
   FunctionArgList Args;
-  ImplicitParamDecl LHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
-                           C.VoidPtrTy);
-  ImplicitParamDecl RHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
-                           C.VoidPtrTy);
+  ImplicitParamDecl LHSArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
+  ImplicitParamDecl RHSArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   Args.push_back(&LHSArg);
   Args.push_back(&RHSArg);
   auto &CGFI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, Args);
diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index bbedac962d5..3ced05d08a4 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -1252,24 +1252,19 @@ emitReduceScratchpadFunction(CodeGenModule &CGM,
   auto Int32Ty = C.getIntTypeForBitwidth(32, /* Signed */ true);
 
   // Destination of the copy.
-  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ReduceListArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // Base address of the scratchpad array, with each element storing a
   // Reduce list per team.
-  ImplicitParamDecl ScratchPadArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ScratchPadArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // A source index into the scratchpad array.
-  ImplicitParamDecl IndexArg(C, /*DC=*/nullptr, SourceLocation(),
-                             /*Id=*/nullptr, Int32Ty);
+  ImplicitParamDecl IndexArg(C, Int32Ty, ImplicitParamDecl::Other);
   // Row width of an element in the scratchpad array, typically
   // the number of teams.
-  ImplicitParamDecl WidthArg(C, /*DC=*/nullptr, SourceLocation(),
-                             /*Id=*/nullptr, Int32Ty);
+  ImplicitParamDecl WidthArg(C, Int32Ty, ImplicitParamDecl::Other);
   // If should_reduce == 1, then it's load AND reduce,
   // If should_reduce == 0 (or otherwise), then it only loads (+ copy).
   // The latter case is used for initialization.
-  ImplicitParamDecl ShouldReduceArg(C, /*DC=*/nullptr, SourceLocation(),
-                                    /*Id=*/nullptr, Int32Ty);
+  ImplicitParamDecl ShouldReduceArg(C, Int32Ty, ImplicitParamDecl::Other);
 
   FunctionArgList Args;
   Args.push_back(&ReduceListArg);
@@ -1381,20 +1376,16 @@ static llvm::Value *emitCopyToScratchpad(CodeGenModule &CGM,
   auto Int32Ty = C.getIntTypeForBitwidth(32, /* Signed */ true);
 
   // Source of the copy.
-  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ReduceListArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // Base address of the scratchpad array, with each element storing a
   // Reduce list per team.
-  ImplicitParamDecl ScratchPadArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ScratchPadArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // A destination index into the scratchpad array, typically the team
   // identifier.
-  ImplicitParamDecl IndexArg(C, /*DC=*/nullptr, SourceLocation(),
-                             /*Id=*/nullptr, Int32Ty);
+  ImplicitParamDecl IndexArg(C, Int32Ty, ImplicitParamDecl::Other);
   // Row width of an element in the scratchpad array, typically
   // the number of teams.
-  ImplicitParamDecl WidthArg(C, /*DC=*/nullptr, SourceLocation(),
-                             /*Id=*/nullptr, Int32Ty);
+  ImplicitParamDecl WidthArg(C, Int32Ty, ImplicitParamDecl::Other);
 
   FunctionArgList Args;
   Args.push_back(&ReduceListArg);
@@ -1475,13 +1466,12 @@ static llvm::Value *emitInterWarpCopyFunction(CodeGenModule &CGM,
   // ReduceList: thread local Reduce list.
   // At the stage of the computation when this function is called, partially
   // aggregated values reside in the first lane of every active warp.
-  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ReduceListArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // NumWarps: number of warps active in the parallel region.  This could
   // be smaller than 32 (max warps in a CTA) for partial block reduction.
-  ImplicitParamDecl NumWarpsArg(C, /*DC=*/nullptr, SourceLocation(),
-                                /*Id=*/nullptr,
-                                C.getIntTypeForBitwidth(32, /* Signed */ true));
+  ImplicitParamDecl NumWarpsArg(C,
+                                C.getIntTypeForBitwidth(32, /* Signed */ true),
+                                ImplicitParamDecl::Other);
   FunctionArgList Args;
   Args.push_back(&ReduceListArg);
   Args.push_back(&NumWarpsArg);
@@ -1723,17 +1713,14 @@ emitShuffleAndReduceFunction(CodeGenModule &CGM,
   auto &C = CGM.getContext();
 
   // Thread local Reduce list used to host the values of data to be reduced.
-  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
-                                  /*Id=*/nullptr, C.VoidPtrTy);
+  ImplicitParamDecl ReduceListArg(C, C.VoidPtrTy, ImplicitParamDecl::Other);
   // Current lane id; could be logical.
-  ImplicitParamDecl LaneIDArg(C, /*DC=*/nullptr, SourceLocation(),
-                              /*Id=*/nullptr, C.ShortTy);
+  ImplicitParamDecl LaneIDArg(C, C.ShortTy, ImplicitParamDecl::Other);
   // Offset of the remote source lane relative to the current lane.
-  ImplicitParamDecl RemoteLaneOffsetArg(C, /*DC=*/nullptr, SourceLocation(),
-                                        /*Id=*/nullptr, C.ShortTy);
+  ImplicitParamDecl RemoteLaneOffsetArg(C, C.ShortTy,
+                                        ImplicitParamDecl::Other);
   // Algorithm version.  This is expected to be known at compile time.
-  ImplicitParamDecl AlgoVerArg(C, /*DC=*/nullptr, SourceLocation(),
-                               /*Id=*/nullptr, C.ShortTy);
+  ImplicitParamDecl AlgoVerArg(C, C.ShortTy, ImplicitParamDecl::Other);
   FunctionArgList Args;
   Args.push_back(&ReduceListArg);
   Args.push_back(&LaneIDArg);
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index c8c71dd83e9..77f3c332a12 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -281,8 +281,9 @@ CodeGenFunction::GenerateOpenMPCapturedStmtFunction(const CapturedStmt &S) {
       ArgType =
           getCanonicalParamType(getContext(), ArgType.getNonReferenceType());
     }
-    Args.push_back(ImplicitParamDecl::Create(getContext(), nullptr,
-                                             FD->getLocation(), II, ArgType));
+    Args.push_back(ImplicitParamDecl::Create(getContext(), /*DC=*/nullptr,
+                                             FD->getLocation(), II, ArgType,
+                                             ImplicitParamDecl::Other));
     ++I;
   }
   Args.append(
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index b6d7f025501..ac1a1334f10 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1083,10 +1083,9 @@ QualType CodeGenFunction::BuildFunctionArgList(GlobalDecl GD,
       if (!Param->hasAttr<PassObjectSizeAttr>())
         continue;
 
-      IdentifierInfo *NoID = nullptr;
       auto *Implicit = ImplicitParamDecl::Create(
-          getContext(), Param->getDeclContext(), Param->getLocation(), NoID,
-          getContext().getSizeType());
+          getContext(), Param->getDeclContext(), Param->getLocation(),
+          /*Id=*/nullptr, getContext().getSizeType(), ImplicitParamDecl::Other);
       SizeArguments[Param] = Implicit;
       Args.push_back(Implicit);
     }
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 62b0e6155f9..39efb9f4392 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -1408,9 +1408,9 @@ void ItaniumCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
 
     // FIXME: avoid the fake decl
     QualType T = Context.getPointerType(Context.VoidPtrTy);
-    ImplicitParamDecl *VTTDecl
-      = ImplicitParamDecl::Create(Context, nullptr, MD->getLocation(),
-                                  &Context.Idents.get("vtt"), T);
+    auto *VTTDecl = ImplicitParamDecl::Create(
+        Context, /*DC=*/nullptr, MD->getLocation(), &Context.Idents.get("vtt"),
+        T, ImplicitParamDecl::CXXVTT);
     Params.insert(Params.begin() + 1, VTTDecl);
     getStructorImplicitParamDecl(CGF) = VTTDecl;
   }
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index ff5aca88131..e68a16e0bd5 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -1413,11 +1413,10 @@ void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
   assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
   if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
-    ImplicitParamDecl *IsMostDerived
-      = ImplicitParamDecl::Create(Context, nullptr,
-                                  CGF.CurGD.getDecl()->getLocation(),
-                                  &Context.Idents.get("is_most_derived"),
-                                  Context.IntTy);
+    auto *IsMostDerived = ImplicitParamDecl::Create(
+        Context, /*DC=*/nullptr, CGF.CurGD.getDecl()->getLocation(),
+        &Context.Idents.get("is_most_derived"), Context.IntTy,
+        ImplicitParamDecl::Other);
     // The 'most_derived' parameter goes second if the ctor is variadic and last
     // if it's not.  Dtors can't be variadic.
     const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
@@ -1427,11 +1426,10 @@ void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
       Params.push_back(IsMostDerived);
     getStructorImplicitParamDecl(CGF) = IsMostDerived;
   } else if (isDeletingDtor(CGF.CurGD)) {
-    ImplicitParamDecl *ShouldDelete
-      = ImplicitParamDecl::Create(Context, nullptr,
-                                  CGF.CurGD.getDecl()->getLocation(),
-                                  &Context.Idents.get("should_call_delete"),
-                                  Context.IntTy);
+    auto *ShouldDelete = ImplicitParamDecl::Create(
+        Context, /*DC=*/nullptr, CGF.CurGD.getDecl()->getLocation(),
+        &Context.Idents.get("should_call_delete"), Context.IntTy,
+        ImplicitParamDecl::Other);
     Params.push_back(ShouldDelete);
     getStructorImplicitParamDecl(CGF) = ShouldDelete;
   }
@@ -3875,18 +3873,21 @@ MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
   // Following the 'this' pointer is a reference to the source object that we
   // are copying from.
   ImplicitParamDecl SrcParam(
-      getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
+      getContext(), /*DC=*/nullptr, SourceLocation(),
+      &getContext().Idents.get("src"),
       getContext().getLValueReferenceType(RecordTy,
-                                          /*SpelledAsLValue=*/true));
+                                          /*SpelledAsLValue=*/true),
+      ImplicitParamDecl::Other);
   if (IsCopy)
     FunctionArgs.push_back(&SrcParam);
 
   // Constructors for classes which utilize virtual bases have an additional
   // parameter which indicates whether or not it is being delegated to by a more
   // derived constructor.
-  ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
+  ImplicitParamDecl IsMostDerived(getContext(), /*DC=*/nullptr,
+                                  SourceLocation(),
                                   &getContext().Idents.get("is_most_derived"),
-                                  getContext().IntTy);
+                                  getContext().IntTy, ImplicitParamDecl::Other);
   // Only add the parameter to the list if thie class has virtual bases.
   if (RD->getNumVBases() > 0)
     FunctionArgs.push_back(&IsMostDerived);
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index dcb2c11c73c..151b89ab8d2 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3956,8 +3956,9 @@ void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
   DeclContext *DC = CapturedDecl::castToDeclContext(CD);
   IdentifierInfo *ParamName = &Context.Idents.get("__context");
   QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
-  ImplicitParamDecl *Param
-    = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
+  auto *Param =
+      ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
+                                ImplicitParamDecl::CapturedContext);
   DC->addDecl(Param);
 
   CD->setContextParam(0, Param);
@@ -3992,15 +3993,17 @@ void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
              "null type has been found already for '__context' parameter");
       IdentifierInfo *ParamName = &Context.Idents.get("__context");
       QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
-      ImplicitParamDecl *Param
-        = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
+      auto *Param =
+          ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
+                                    ImplicitParamDecl::CapturedContext);
       DC->addDecl(Param);
       CD->setContextParam(ParamNum, Param);
       ContextIsFound = true;
     } else {
       IdentifierInfo *ParamName = &Context.Idents.get(I->first);
-      ImplicitParamDecl *Param
-        = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second);
+      auto *Param =
+          ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
+                                    ImplicitParamDecl::CapturedContext);
       DC->addDecl(Param);
       CD->setParam(ParamNum, Param);
     }
@@ -4010,8 +4013,9 @@ void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
     // Add __context implicitly if it is not specified.
     IdentifierInfo *ParamName = &Context.Idents.get("__context");
     QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
-    ImplicitParamDecl *Param =
-        ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
+    auto *Param =
+        ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
+                                  ImplicitParamDecl::CapturedContext);
     DC->addDecl(Param);
     CD->setContextParam(ParamNum, Param);
   }
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index f3ee9078298..ed103e62921 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -1229,6 +1229,7 @@ ASTDeclReader::RedeclarableResult ASTDeclReader::VisitVarDeclImpl(VarDecl *VD) {
     VD->NonParmVarDeclBits.IsConstexpr = Record.readInt();
     VD->NonParmVarDeclBits.IsInitCapture = Record.readInt();
     VD->NonParmVarDeclBits.PreviousDeclInSameBlockScope = Record.readInt();
+    VD->NonParmVarDeclBits.ImplicitParamKind = Record.readInt();
   }
   Linkage VarLinkage = Linkage(Record.readInt());
   VD->setCachedLinkage(VarLinkage);
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 8fa64aa1b9d..2d648cb103c 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -915,6 +915,10 @@ void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
     Record.push_back(D->isConstexpr());
     Record.push_back(D->isInitCapture());
     Record.push_back(D->isPreviousDeclInSameBlockScope());
+    if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
+      Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
+    else
+      Record.push_back(0);
   }
   Record.push_back(D->getLinkageInternal());
 
@@ -1989,6 +1993,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
+  Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // IsInitICE (local)
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)