Reland "[Attr] Fix parameter indexing for several attributes"

Relands r326602 (reverted in r326862) with new test and fix for
PR36620.

Differential Revision: https://reviews.llvm.org/D43248

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@327405 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/AST/Attr.h

@@ -195,6 +195,128 @@ public:
    }
 };
 
+/// A single parameter index whose accessors require each use to make explicit
+/// the parameter index encoding needed.
+class ParamIdx {
+  // Idx is exposed only via accessors that specify specific encodings.
+  unsigned Idx : 30;
+  unsigned HasThis : 1;
+  unsigned IsValid : 1;
+
+  void assertComparable(const ParamIdx &I) const {
+    assert(isValid() && I.isValid() &&
+           "ParamIdx must be valid to be compared");
+    // It's possible to compare indices from separate functions, but so far
+    // it's not proven useful.  Moreover, it might be confusing because a
+    // comparison on the results of getASTIndex might be inconsistent with a
+    // comparison on the ParamIdx objects themselves.
+    assert(HasThis == I.HasThis &&
+           "ParamIdx must be for the same function to be compared");
+  }
+
+public:
+  /// Construct an invalid parameter index (\c isValid returns false and
+  /// accessors fail an assert).
+  ParamIdx() : Idx(0), HasThis(false), IsValid(false) {}
+
+  /// \param Idx is the parameter index as it is normally specified in
+  /// attributes in the source: one-origin including any C++ implicit this
+  /// parameter.
+  ///
+  /// \param D is the declaration containing the parameters.  It is used to
+  /// determine if there is a C++ implicit this parameter.
+  ParamIdx(unsigned Idx, const Decl *D)
+      : Idx(Idx), HasThis(false), IsValid(true) {
+    assert(Idx >= 1 && "Idx must be one-origin");
+    if (const auto *FD = dyn_cast<FunctionDecl>(D))
+      HasThis = FD->isCXXInstanceMember();
+  }
+
+  /// A type into which \c ParamIdx can be serialized.
+  ///
+  /// A static assertion that it's of the correct size follows the \c ParamIdx
+  /// class definition.
+  typedef uint32_t SerialType;
+
+  /// Produce a representation that can later be passed to \c deserialize to
+  /// construct an equivalent \c ParamIdx.
+  SerialType serialize() const {
+    return *reinterpret_cast<const SerialType *>(this);
+  }
+
+  /// Construct from a result from \c serialize.
+  static ParamIdx deserialize(SerialType S) {
+    ParamIdx P(*reinterpret_cast<ParamIdx *>(&S));
+    assert((!P.IsValid || P.Idx >= 1) && "valid Idx must be one-origin");
+    return P;
+  }
+
+  /// Is this parameter index valid?
+  bool isValid() const { return IsValid; }
+
+  /// Get the parameter index as it would normally be encoded for attributes at
+  /// the source level of representation: one-origin including any C++ implicit
+  /// this parameter.
+  ///
+  /// This encoding thus makes sense for diagnostics, pretty printing, and
+  /// constructing new attributes from a source-like specification.
+  unsigned getSourceIndex() const {
+    assert(isValid() && "ParamIdx must be valid");
+    return Idx;
+  }
+
+  /// Get the parameter index as it would normally be encoded at the AST level
+  /// of representation: zero-origin not including any C++ implicit this
+  /// parameter.
+  ///
+  /// This is the encoding primarily used in Sema.  However, in diagnostics,
+  /// Sema uses \c getSourceIndex instead.
+  unsigned getASTIndex() const {
+    assert(isValid() && "ParamIdx must be valid");
+    assert(Idx >= 1 + HasThis &&
+           "stored index must be base-1 and not specify C++ implicit this");
+    return Idx - 1 - HasThis;
+  }
+
+  /// Get the parameter index as it would normally be encoded at the LLVM level
+  /// of representation: zero-origin including any C++ implicit this parameter.
+  ///
+  /// This is the encoding primarily used in CodeGen.
+  unsigned getLLVMIndex() const {
+    assert(isValid() && "ParamIdx must be valid");
+    assert(Idx >= 1 && "stored index must be base-1");
+    return Idx - 1;
+  }
+
+  bool operator==(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx == I.Idx;
+  }
+  bool operator!=(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx != I.Idx;
+  }
+  bool operator<(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx < I.Idx;
+  }
+  bool operator>(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx > I.Idx;
+  }
+  bool operator<=(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx <= I.Idx;
+  }
+  bool operator>=(const ParamIdx &I) const {
+    assertComparable(I);
+    return Idx >= I.Idx;
+  }
+};
+
+static_assert(sizeof(ParamIdx) == sizeof(ParamIdx::SerialType),
+              "ParamIdx does not fit its serialization type");
+
 #include "clang/AST/Attrs.inc"
 
 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,

include/clang/Basic/Attr.td

@@ -169,6 +169,12 @@ class VariadicUnsignedArgument<string name> : Argument<name, 1>;
 class VariadicExprArgument<string name> : Argument<name, 1>;
 class VariadicStringArgument<string name> : Argument<name, 1>;
 
+// Like VariadicUnsignedArgument except values are ParamIdx.
+class VariadicParamIdxArgument<string name> : Argument<name, 1>;
+
+// Like VariadicParamIdxArgument but for a single function parameter index.
+class ParamIdxArgument<string name, bit opt = 0> : Argument<name, opt>;
+
 // A version of the form major.minor[.subminor].
 class VersionArgument<string name, bit opt = 0> : Argument<name, opt>;
 
@@ -614,6 +620,12 @@ def XRayInstrument : InheritableAttr {
 def XRayLogArgs : InheritableAttr {
   let Spellings = [Clang<"xray_log_args">];
   let Subjects = SubjectList<[Function, ObjCMethod]>;
+  // This argument is a count not an index, so it has the same encoding (base
+  // 1 including C++ implicit this parameter) at the source and LLVM levels of
+  // representation, so ParamIdxArgument is inappropriate.  It is never used
+  // at the AST level of representation, so it never needs to be adjusted not
+  // to include any C++ implicit this parameter.  Thus, we just store it and
+  // use it as an unsigned that never needs adjustment.
   let Args = [UnsignedArgument<"ArgumentCount">];
   let Documentation = [XRayDocs];
 }
@@ -1021,7 +1033,8 @@ def EmptyBases : InheritableAttr, TargetSpecificAttr<TargetMicrosoftCXXABI> {
 def AllocSize : InheritableAttr {
   let Spellings = [GCC<"alloc_size">];
   let Subjects = SubjectList<[Function]>;
-  let Args = [IntArgument<"ElemSizeParam">, IntArgument<"NumElemsParam", 1>];
+  let Args = [ParamIdxArgument<"ElemSizeParam">,
+              ParamIdxArgument<"NumElemsParam", /*opt*/ 1>];
   let TemplateDependent = 1;
   let Documentation = [AllocSizeDocs];
 }
@@ -1108,7 +1121,7 @@ def Format : InheritableAttr {
 
 def FormatArg : InheritableAttr {
   let Spellings = [GCC<"format_arg">];
-  let Args = [IntArgument<"FormatIdx">];
+  let Args = [ParamIdxArgument<"FormatIdx">];
   let Subjects = SubjectList<[ObjCMethod, HasFunctionProto]>;
   let Documentation = [Undocumented];
 }
@@ -1388,16 +1401,16 @@ def NonNull : InheritableParamAttr {
   let Spellings = [GCC<"nonnull">];
   let Subjects = SubjectList<[ObjCMethod, HasFunctionProto, ParmVar], WarnDiag,
                              "functions, methods, and parameters">;
-  let Args = [VariadicUnsignedArgument<"Args">];
+  let Args = [VariadicParamIdxArgument<"Args">];
-  let AdditionalMembers =
+  let AdditionalMembers = [{
-[{bool isNonNull(unsigned idx) const {
+    bool isNonNull(unsigned IdxAST) const {
-    if (!args_size())
+      if (!args_size())
-      return true;
-    for (const auto &V : args())
-      if (V == idx)
         return true;
-    return false;
+      return args_end() != std::find_if(
-  } }];
+          args_begin(), args_end(),
+          [=](const ParamIdx &Idx) { return Idx.getASTIndex() == IdxAST; });
+    }
+  }];
   // FIXME: We should merge duplicates into a single nonnull attribute.
   let InheritEvenIfAlreadyPresent = 1;
   let Documentation = [NonNullDocs];
@@ -1455,7 +1468,7 @@ def AssumeAligned : InheritableAttr {
 def AllocAlign : InheritableAttr {
   let Spellings = [GCC<"alloc_align">];
   let Subjects = SubjectList<[HasFunctionProto]>;
-  let Args = [IntArgument<"ParamIndex">];
+  let Args = [ParamIdxArgument<"ParamIndex">];
   let Documentation = [AllocAlignDocs];
 }
 
@@ -1664,7 +1677,8 @@ def Ownership : InheritableAttr {
              Returns;
     }
   }];
-  let Args = [IdentifierArgument<"Module">, VariadicUnsignedArgument<"Args">];
+  let Args = [IdentifierArgument<"Module">,
+              VariadicParamIdxArgument<"Args">];
   let Subjects = SubjectList<[HasFunctionProto]>;
   let Documentation = [Undocumented];
 }
@@ -2490,8 +2504,8 @@ def ArgumentWithTypeTag : InheritableAttr {
                    Clang<"pointer_with_type_tag">];
   let Subjects = SubjectList<[HasFunctionProto], ErrorDiag>;
   let Args = [IdentifierArgument<"ArgumentKind">,
-              UnsignedArgument<"ArgumentIdx">,
+              ParamIdxArgument<"ArgumentIdx">,
-              UnsignedArgument<"TypeTagIdx">,
+              ParamIdxArgument<"TypeTagIdx">,
               BoolArgument<"IsPointer", /*opt*/0, /*fake*/1>];
   let Documentation = [ArgumentWithTypeTagDocs, PointerWithTypeTagDocs];
 }

lib/AST/ExprConstant.cpp

@@ -5475,9 +5475,8 @@ static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
                                             llvm::APInt &Result) {
   const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
 
-  // alloc_size args are 1-indexed, 0 means not present.
+  assert(AllocSize && AllocSize->getElemSizeParam().isValid());
-  assert(AllocSize && AllocSize->getElemSizeParam() != 0);
+  unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
-  unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
   unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
   if (Call->getNumArgs() <= SizeArgNo)
     return false;
@@ -5495,14 +5494,13 @@ static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
   if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
     return false;
 
-  if (!AllocSize->getNumElemsParam()) {
+  if (!AllocSize->getNumElemsParam().isValid()) {
     Result = std::move(SizeOfElem);
     return true;
   }
 
   APSInt NumberOfElems;
-  // Argument numbers start at 1
+  unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
-  unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
   if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
     return false;
 

lib/CodeGen/CGCall.cpp

@@ -1847,10 +1847,9 @@ void CodeGenModule::ConstructAttributeList(
     HasOptnone = TargetDecl->hasAttr<OptimizeNoneAttr>();
     if (auto *AllocSize = TargetDecl->getAttr<AllocSizeAttr>()) {
       Optional<unsigned> NumElemsParam;
-      // alloc_size args are base-1, 0 means not present.
+      if (AllocSize->getNumElemsParam().isValid())
-      if (unsigned N = AllocSize->getNumElemsParam())
+        NumElemsParam = AllocSize->getNumElemsParam().getLLVMIndex();
-        NumElemsParam = N - 1;
+      FuncAttrs.addAllocSizeAttr(AllocSize->getElemSizeParam().getLLVMIndex(),
-      FuncAttrs.addAllocSizeAttr(AllocSize->getElemSizeParam() - 1,
                                  NumElemsParam);
     }
   }
@@ -4399,7 +4398,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
                               OffsetValue);
     } else if (const auto *AA = TargetDecl->getAttr<AllocAlignAttr>()) {
       llvm::Value *ParamVal =
-          CallArgs[AA->getParamIndex() - 1].RV.getScalarVal();
+          CallArgs[AA->getParamIndex().getLLVMIndex()].RV.getScalarVal();
       EmitAlignmentAssumption(Ret.getScalarVal(), ParamVal);
     }
   }

lib/Sema/SemaChecking.cpp

@@ -2619,12 +2619,13 @@ static void CheckNonNullArguments(Sema &S,
         return;
       }
 
-      for (unsigned Val : NonNull->args()) {
+      for (const ParamIdx &Idx : NonNull->args()) {
-        if (Val >= Args.size())
+        unsigned IdxAST = Idx.getASTIndex();
+        if (IdxAST >= Args.size())
           continue;
         if (NonNullArgs.empty())
           NonNullArgs.resize(Args.size());
-        NonNullArgs.set(Val);
+        NonNullArgs.set(IdxAST);
       }
     }
   }
@@ -5002,12 +5003,7 @@ checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args,
     const CallExpr *CE = cast<CallExpr>(E);
     if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
       if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
-        unsigned ArgIndex = FA->getFormatIdx();
+        const Expr *Arg = CE->getArg(FA->getFormatIdx().getASTIndex());
-        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
-          if (MD->isInstance())
-            --ArgIndex;
-        const Expr *Arg = CE->getArg(ArgIndex - 1);
-
         return checkFormatStringExpr(S, Arg, Args,
                                      HasVAListArg, format_idx, firstDataArg,
                                      Type, CallType, InFunctionCall,
@@ -5032,8 +5028,7 @@ checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args,
     const auto *ME = cast<ObjCMessageExpr>(E);
     if (const auto *ND = ME->getMethodDecl()) {
       if (const auto *FA = ND->getAttr<FormatArgAttr>()) {
-        unsigned ArgIndex = FA->getFormatIdx();
+        const Expr *Arg = ME->getArg(FA->getFormatIdx().getASTIndex());
-        const Expr *Arg = ME->getArg(ArgIndex - 1);
         return checkFormatStringExpr(
             S, Arg, Args, HasVAListArg, format_idx, firstDataArg, Type,
             CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, Offset);
@@ -10086,8 +10081,8 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
               return;
           }
 
-          for (unsigned ArgNo : NonNull->args()) {
+          for (const ParamIdx &ArgNo : NonNull->args()) {
-            if (ArgNo == ParamNo) {
+            if (ArgNo.getASTIndex() == ParamNo) {
               ComplainAboutNonnullParamOrCall(NonNull);
               return;
             }
@@ -12242,13 +12237,13 @@ void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
   bool IsPointerAttr = Attr->getIsPointer();
 
   // Retrieve the argument representing the 'type_tag'.
-  if (Attr->getTypeTagIdx() >= ExprArgs.size()) {
+  unsigned TypeTagIdxAST = Attr->getTypeTagIdx().getASTIndex();
-    // Add 1 to display the user's specified value.
+  if (TypeTagIdxAST >= ExprArgs.size()) {
     Diag(CallSiteLoc, diag::err_tag_index_out_of_range)
-        << 0 << Attr->getTypeTagIdx() + 1;
+        << 0 << Attr->getTypeTagIdx().getSourceIndex();
     return;
   }
-  const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
+  const Expr *TypeTagExpr = ExprArgs[TypeTagIdxAST];
   bool FoundWrongKind;
   TypeTagData TypeInfo;
   if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
@@ -12262,13 +12257,13 @@ void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
   }
 
   // Retrieve the argument representing the 'arg_idx'.
-  if (Attr->getArgumentIdx() >= ExprArgs.size()) {
+  unsigned ArgumentIdxAST = Attr->getArgumentIdx().getASTIndex();
-    // Add 1 to display the user's specified value.
+  if (ArgumentIdxAST >= ExprArgs.size()) {
     Diag(CallSiteLoc, diag::err_tag_index_out_of_range)
-        << 1 << Attr->getArgumentIdx() + 1;
+        << 1 << Attr->getArgumentIdx().getSourceIndex();
     return;
   }
-  const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
+  const Expr *ArgumentExpr = ExprArgs[ArgumentIdxAST];
   if (IsPointerAttr) {
     // Skip implicit cast of pointer to `void *' (as a function argument).
     if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))

lib/Sema/SemaDecl.cpp

@@ -13185,7 +13185,7 @@ void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
     // We already have a __builtin___CFStringMakeConstantString,
     // but builds that use -fno-constant-cfstrings don't go through that.
     if (!FD->hasAttr<FormatArgAttr>())
-      FD->addAttr(FormatArgAttr::CreateImplicit(Context, 1,
+      FD->addAttr(FormatArgAttr::CreateImplicit(Context, ParamIdx(1, FD),
                                                 FD->getLocation()));
   }
 }

lib/Sema/SemaDeclAttr.cpp

@@ -312,7 +312,7 @@ static bool checkAttrMutualExclusion(Sema &S, Decl *D, SourceRange Range,
 template <typename AttrInfo>
 static bool checkFunctionOrMethodParameterIndex(
     Sema &S, const Decl *D, const AttrInfo &AI, unsigned AttrArgNum,
-    const Expr *IdxExpr, uint64_t &Idx, bool AllowImplicitThis = false) {
+    const Expr *IdxExpr, ParamIdx &Idx, bool CanIndexImplicitThis = false) {
   assert(isFunctionOrMethodOrBlock(D));
 
   // In C++ the implicit 'this' function parameter also counts.
@@ -332,23 +332,22 @@ static bool checkFunctionOrMethodParameterIndex(
     return false;
   }
 
-  Idx = IdxInt.getLimitedValue();
+  unsigned IdxSource = IdxInt.getLimitedValue(UINT_MAX);
-  if (Idx < 1 || (!IV && Idx > NumParams)) {
+  if (IdxSource < 1 || (!IV && IdxSource > NumParams)) {
     S.Diag(getAttrLoc(AI), diag::err_attribute_argument_out_of_bounds)
-      << getAttrName(AI) << AttrArgNum << IdxExpr->getSourceRange();
+        << getAttrName(AI) << AttrArgNum << IdxExpr->getSourceRange();
     return false;
   }
-  Idx--; // Convert to zero-based.
+  if (HasImplicitThisParam && !CanIndexImplicitThis) {
-  if (HasImplicitThisParam && !AllowImplicitThis) {
+    if (IdxSource == 1) {
-    if (Idx == 0) {
       S.Diag(getAttrLoc(AI),
              diag::err_attribute_invalid_implicit_this_argument)
-        << getAttrName(AI) << IdxExpr->getSourceRange();
+          << getAttrName(AI) << IdxExpr->getSourceRange();
       return false;
     }
-    --Idx;
   }
 
+  Idx = ParamIdx(IdxSource, D);
   return true;
 }
 
@@ -773,18 +772,15 @@ static void handleAssertExclusiveLockAttr(Sema &S, Decl *D,
 /// AttrArgNo is used to actually retrieve the argument, so it's base-0.
 template <typename AttrInfo>
 static bool checkParamIsIntegerType(Sema &S, const FunctionDecl *FD,
-                                    const AttrInfo &AI, unsigned AttrArgNo,
+                                    const AttrInfo &AI, unsigned AttrArgNo) {
-                                    bool AllowDependentType = false) {
   assert(AI.isArgExpr(AttrArgNo) && "Expected expression argument");
   Expr *AttrArg = AI.getArgAsExpr(AttrArgNo);
-  uint64_t Idx;
+  ParamIdx Idx;
   if (!checkFunctionOrMethodParameterIndex(S, FD, AI, AttrArgNo + 1, AttrArg,
                                            Idx))
     return false;
 
-  const ParmVarDecl *Param = FD->getParamDecl(Idx);
+  const ParmVarDecl *Param = FD->getParamDecl(Idx.getASTIndex());
-  if (AllowDependentType && Param->getType()->isDependentType())
-    return true;
   if (!Param->getType()->isIntegerType() && !Param->getType()->isCharType()) {
     SourceLocation SrcLoc = AttrArg->getLocStart();
     S.Diag(SrcLoc, diag::err_attribute_integers_only)
@@ -807,25 +803,24 @@ static void handleAllocSizeAttr(Sema &S, Decl *D, const AttributeList &AL) {
   }
 
   const Expr *SizeExpr = AL.getArgAsExpr(0);
-  int SizeArgNo;
+  int SizeArgNoVal;
   // Parameter indices are 1-indexed, hence Index=1
-  if (!checkPositiveIntArgument(S, AL, SizeExpr, SizeArgNo, /*Index=*/1))
+  if (!checkPositiveIntArgument(S, AL, SizeExpr, SizeArgNoVal, /*Index=*/1))
     return;
-
   if (!checkParamIsIntegerType(S, FD, AL, /*AttrArgNo=*/0))
     return;
+  ParamIdx SizeArgNo(SizeArgNoVal, D);
 
-  // Args are 1-indexed, so 0 implies that the arg was not present
+  ParamIdx NumberArgNo;
-  int NumberArgNo = 0;
   if (AL.getNumArgs() == 2) {
     const Expr *NumberExpr = AL.getArgAsExpr(1);
+    int Val;
     // Parameter indices are 1-based, hence Index=2
-    if (!checkPositiveIntArgument(S, AL, NumberExpr, NumberArgNo,
+    if (!checkPositiveIntArgument(S, AL, NumberExpr, Val, /*Index=*/2))
-                                  /*Index=*/2))
       return;
-
     if (!checkParamIsIntegerType(S, FD, AL, /*AttrArgNo=*/1))
       return;
+    NumberArgNo = ParamIdx(Val, D);
   }
 
   D->addAttr(::new (S.Context)
@@ -1425,18 +1420,19 @@ static bool attrNonNullArgCheck(Sema &S, QualType T, const AttributeList &AL,
 }
 
 static void handleNonNullAttr(Sema &S, Decl *D, const AttributeList &AL) {
-  SmallVector<unsigned, 8> NonNullArgs;
+  SmallVector<ParamIdx, 8> NonNullArgs;
   for (unsigned I = 0; I < AL.getNumArgs(); ++I) {
     Expr *Ex = AL.getArgAsExpr(I);
-    uint64_t Idx;
+    ParamIdx Idx;
     if (!checkFunctionOrMethodParameterIndex(S, D, AL, I + 1, Ex, Idx))
       return;
 
     // Is the function argument a pointer type?
-    if (Idx < getFunctionOrMethodNumParams(D) &&
+    if (Idx.getASTIndex() < getFunctionOrMethodNumParams(D) &&
-        !attrNonNullArgCheck(S, getFunctionOrMethodParamType(D, Idx), AL,
+        !attrNonNullArgCheck(
-                             Ex->getSourceRange(),
+            S, getFunctionOrMethodParamType(D, Idx.getASTIndex()), AL,
-                             getFunctionOrMethodParamRange(D, Idx)))
+            Ex->getSourceRange(),
+            getFunctionOrMethodParamRange(D, Idx.getASTIndex())))
       continue;
 
     NonNullArgs.push_back(Idx);
@@ -1460,12 +1456,12 @@ static void handleNonNullAttr(Sema &S, Decl *D, const AttributeList &AL) {
       S.Diag(AL.getLoc(), diag::warn_attribute_nonnull_no_pointers);
   }
 
-  unsigned *Start = NonNullArgs.data();
+  ParamIdx *Start = NonNullArgs.data();
   unsigned Size = NonNullArgs.size();
   llvm::array_pod_sort(Start, Start + Size);
   D->addAttr(::new (S.Context)
-             NonNullAttr(AL.getRange(), S.Context, Start, Size,
+                 NonNullAttr(AL.getRange(), S.Context, Start, Size,
-                         AL.getAttributeSpellingListIndex()));
+                             AL.getAttributeSpellingListIndex()));
 }
 
 static void handleNonNullAttrParameter(Sema &S, ParmVarDecl *D,
@@ -1486,8 +1482,8 @@ static void handleNonNullAttrParameter(Sema &S, ParmVarDecl *D,
     return;
 
   D->addAttr(::new (S.Context)
-             NonNullAttr(AL.getRange(), S.Context, nullptr, 0,
+                 NonNullAttr(AL.getRange(), S.Context, nullptr, 0,
-                         AL.getAttributeSpellingListIndex()));
+                             AL.getAttributeSpellingListIndex()));
 }
 
 static void handleReturnsNonNullAttr(Sema &S, Decl *D,
@@ -1588,7 +1584,7 @@ void Sema::AddAllocAlignAttr(SourceRange AttrRange, Decl *D, Expr *ParamExpr,
                              unsigned SpellingListIndex) {
   QualType ResultType = getFunctionOrMethodResultType(D);
 
-  AllocAlignAttr TmpAttr(AttrRange, Context, 0, SpellingListIndex);
+  AllocAlignAttr TmpAttr(AttrRange, Context, ParamIdx(), SpellingListIndex);
   SourceLocation AttrLoc = AttrRange.getBegin();
 
   if (!ResultType->isDependentType() &&
@@ -1598,28 +1594,22 @@ void Sema::AddAllocAlignAttr(SourceRange AttrRange, Decl *D, Expr *ParamExpr,
     return;
   }
 
-  uint64_t IndexVal;
+  ParamIdx Idx;
   const auto *FuncDecl = cast<FunctionDecl>(D);
   if (!checkFunctionOrMethodParameterIndex(*this, FuncDecl, TmpAttr,
-                                           /*AttrArgNo=*/1, ParamExpr,
+                                           /*AttrArgNo=*/1, ParamExpr, Idx))
-                                           IndexVal))
     return;
 
-  QualType Ty = getFunctionOrMethodParamType(D, IndexVal);
+  QualType Ty = getFunctionOrMethodParamType(D, Idx.getASTIndex());
   if (!Ty->isDependentType() && !Ty->isIntegralType(Context)) {
     Diag(ParamExpr->getLocStart(), diag::err_attribute_integers_only)
-        << &TmpAttr << FuncDecl->getParamDecl(IndexVal)->getSourceRange();
+        << &TmpAttr
+        << FuncDecl->getParamDecl(Idx.getASTIndex())->getSourceRange();
     return;
   }
 
-  // We cannot use the Idx returned from checkFunctionOrMethodParameterIndex
+  D->addAttr(::new (Context)
-  // because that has corrected for the implicit this parameter, and is zero-
+                 AllocAlignAttr(AttrRange, Context, Idx, SpellingListIndex));
-  // based.  The attribute expects what the user wrote explicitly.
-  llvm::APSInt Val;
-  ParamExpr->EvaluateAsInt(Val, Context);
-
-  D->addAttr(::new (Context) AllocAlignAttr(
-      AttrRange, Context, Val.getZExtValue(), SpellingListIndex));
 }
 
 /// Normalize the attribute, __foo__ becomes foo.
@@ -1679,15 +1669,15 @@ static void handleOwnershipAttr(Sema &S, Decl *D, const AttributeList &AL) {
     Module = &S.PP.getIdentifierTable().get(ModuleName);
   }
 
-  SmallVector<unsigned, 8> OwnershipArgs;
+  SmallVector<ParamIdx, 8> OwnershipArgs;
   for (unsigned i = 1; i < AL.getNumArgs(); ++i) {
     Expr *Ex = AL.getArgAsExpr(i);
-    uint64_t Idx;
+    ParamIdx Idx;
     if (!checkFunctionOrMethodParameterIndex(S, D, AL, i, Ex, Idx))
       return;
 
     // Is the function argument a pointer type?
-    QualType T = getFunctionOrMethodParamType(D, Idx);
+    QualType T = getFunctionOrMethodParamType(D, Idx.getASTIndex());
     int Err = -1;  // No error
     switch (K) {
       case OwnershipAttr::Takes:
@@ -1718,14 +1708,13 @@ static void handleOwnershipAttr(Sema &S, Decl *D, const AttributeList &AL) {
       } else if (K == OwnershipAttr::Returns &&
                  I->getOwnKind() == OwnershipAttr::Returns) {
         // A returns attribute conflicts with any other returns attribute using
-        // a different index. Note, diagnostic reporting is 1-based, but stored
+        // a different index.
-        // argument indexes are 0-based.
         if (std::find(I->args_begin(), I->args_end(), Idx) == I->args_end()) {
           S.Diag(I->getLocation(), diag::err_ownership_returns_index_mismatch)
-              << *(I->args_begin()) + 1;
+              << I->args_begin()->getSourceIndex();
           if (I->args_size())
             S.Diag(AL.getLoc(), diag::note_ownership_returns_index_mismatch)
-                << (unsigned)Idx + 1 << Ex->getSourceRange();
+                << Idx.getSourceIndex() << Ex->getSourceRange();
           return;
         }
       }
@@ -1733,13 +1722,12 @@ static void handleOwnershipAttr(Sema &S, Decl *D, const AttributeList &AL) {
     OwnershipArgs.push_back(Idx);
   }
 
-  unsigned* start = OwnershipArgs.data();
+  ParamIdx *Start = OwnershipArgs.data();
-  unsigned size = OwnershipArgs.size();
+  unsigned Size = OwnershipArgs.size();
-  llvm::array_pod_sort(start, start + size);
+  llvm::array_pod_sort(Start, Start + Size);
-
   D->addAttr(::new (S.Context)
-             OwnershipAttr(AL.getLoc(), S.Context, Module, start, size,
+                 OwnershipAttr(AL.getLoc(), S.Context, Module, Start, Size,
-                           AL.getAttributeSpellingListIndex()));
+                               AL.getAttributeSpellingListIndex()));
 }
 
 static void handleWeakRefAttr(Sema &S, Decl *D, const AttributeList &AL) {
@@ -3057,12 +3045,12 @@ static void handleEnumExtensibilityAttr(Sema &S, Decl *D,
 /// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
 static void handleFormatArgAttr(Sema &S, Decl *D, const AttributeList &AL) {
   Expr *IdxExpr = AL.getArgAsExpr(0);
-  uint64_t Idx;
+  ParamIdx Idx;
   if (!checkFunctionOrMethodParameterIndex(S, D, AL, 1, IdxExpr, Idx))
     return;
 
   // Make sure the format string is really a string.
-  QualType Ty = getFunctionOrMethodParamType(D, Idx);
+  QualType Ty = getFunctionOrMethodParamType(D, Idx.getASTIndex());
 
   bool NotNSStringTy = !isNSStringType(Ty, S.Context);
   if (NotNSStringTy &&
@@ -3085,15 +3073,8 @@ static void handleFormatArgAttr(Sema &S, Decl *D, const AttributeList &AL) {
     return;
   }
 
-  // We cannot use the Idx returned from checkFunctionOrMethodParameterIndex
+  D->addAttr(::new (S.Context) FormatArgAttr(
-  // because that has corrected for the implicit this parameter, and is zero-
+      AL.getRange(), S.Context, Idx, AL.getAttributeSpellingListIndex()));
-  // based.  The attribute expects what the user wrote explicitly.
-  llvm::APSInt Val;
-  IdxExpr->EvaluateAsInt(Val, S.Context);
-
-  D->addAttr(::new (S.Context)
-             FormatArgAttr(AL.getRange(), S.Context, Val.getZExtValue(),
-                           AL.getAttributeSpellingListIndex()));
 }
 
 enum FormatAttrKind {
@@ -4487,13 +4468,13 @@ static void handleArgumentWithTypeTagAttr(Sema &S, Decl *D,
       << AL.getName() << /* arg num = */ 1 << AANT_ArgumentIdentifier;
     return;
   }
-  
+
-  uint64_t ArgumentIdx;
+  ParamIdx ArgumentIdx;
   if (!checkFunctionOrMethodParameterIndex(S, D, AL, 2, AL.getArgAsExpr(1),
                                            ArgumentIdx))
     return;
 
-  uint64_t TypeTagIdx;
+  ParamIdx TypeTagIdx;
   if (!checkFunctionOrMethodParameterIndex(S, D, AL, 3, AL.getArgAsExpr(2),
                                            TypeTagIdx))
     return;
@@ -4501,8 +4482,9 @@ static void handleArgumentWithTypeTagAttr(Sema &S, Decl *D,
   bool IsPointer = AL.getName()->getName() == "pointer_with_type_tag";
   if (IsPointer) {
     // Ensure that buffer has a pointer type.
-    if (ArgumentIdx >= getFunctionOrMethodNumParams(D) ||
+    unsigned ArgumentIdxAST = ArgumentIdx.getASTIndex();
-        !getFunctionOrMethodParamType(D, ArgumentIdx)->isPointerType())
+    if (ArgumentIdxAST >= getFunctionOrMethodNumParams(D) ||
+        !getFunctionOrMethodParamType(D, ArgumentIdxAST)->isPointerType())
       S.Diag(AL.getLoc(), diag::err_attribute_pointers_only)
           << AL.getName() << 0;
   }
@@ -4542,19 +4524,18 @@ static void handleTypeTagForDatatypeAttr(Sema &S, Decl *D,
                                     AL.getAttributeSpellingListIndex()));
 }
 
-static void handleXRayLogArgsAttr(Sema &S, Decl *D,
+static void handleXRayLogArgsAttr(Sema &S, Decl *D, const AttributeList &AL) {
-                                  const AttributeList &AL) {
+  ParamIdx ArgCount;
-  uint64_t ArgCount;
 
   if (!checkFunctionOrMethodParameterIndex(S, D, AL, 1, AL.getArgAsExpr(0),
                                            ArgCount,
-                                           true /* AllowImplicitThis*/))
+                                           true /* CanIndexImplicitThis */))
     return;
 
-  // ArgCount isn't a parameter index [0;n), it's a count [1;n] - hence + 1.
+  // ArgCount isn't a parameter index [0;n), it's a count [1;n]
-  D->addAttr(::new (S.Context)
+  D->addAttr(::new (S.Context) XRayLogArgsAttr(
-                 XRayLogArgsAttr(AL.getRange(), S.Context, ++ArgCount,
+      AL.getRange(), S.Context, ArgCount.getSourceIndex(),
-                                 AL.getAttributeSpellingListIndex()));
+      AL.getAttributeSpellingListIndex()));
 }
 
 //===----------------------------------------------------------------------===//

lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -176,7 +176,8 @@ static void instantiateDependentAllocAlignAttr(
     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
     const AllocAlignAttr *Align, Decl *New) {
   Expr *Param = IntegerLiteral::Create(
-      S.getASTContext(), llvm::APInt(64, Align->getParamIndex()),
+      S.getASTContext(),
+      llvm::APInt(64, Align->getParamIndex().getSourceIndex()),
       S.getASTContext().UnsignedLongLongTy, Align->getLocation());
   S.AddAllocAlignAttr(Align->getLocation(), New, Param,
                       Align->getSpellingListIndex());

lib/StaticAnalyzer/Checkers/MallocChecker.cpp

@@ -1231,9 +1231,10 @@ MallocChecker::MallocMemReturnsAttr(CheckerContext &C, const CallExpr *CE,
   if (Att->getModule() != II_malloc)
     return nullptr;
 
-  OwnershipAttr::args_iterator I = Att->args_begin(), E = Att->args_end();
+  ParamIdx *I = Att->args_begin(), *E = Att->args_end();
   if (I != E) {
-    return MallocMemAux(C, CE, CE->getArg(*I), UndefinedVal(), State);
+    return MallocMemAux(C, CE, CE->getArg(I->getASTIndex()), UndefinedVal(),
+                        State);
   }
   return MallocMemAux(C, CE, UnknownVal(), UndefinedVal(), State);
 }
@@ -1331,9 +1332,9 @@ ProgramStateRef MallocChecker::FreeMemAttr(CheckerContext &C,
   bool ReleasedAllocated = false;
 
   for (const auto &Arg : Att->args()) {
-    ProgramStateRef StateI = FreeMemAux(C, CE, State, Arg,
+    ProgramStateRef StateI = FreeMemAux(
-                               Att->getOwnKind() == OwnershipAttr::Holds,
+        C, CE, State, Arg.getASTIndex(),
-                               ReleasedAllocated);
+        Att->getOwnKind() == OwnershipAttr::Holds, ReleasedAllocated);
     if (StateI)
       State = StateI;
   }

lib/StaticAnalyzer/Checkers/NonNullParamChecker.cpp

@@ -54,10 +54,11 @@ static llvm::SmallBitVector getNonNullAttrs(const CallEvent &Call) {
       AttrNonNull.set(0, NumArgs);
       break;
     }
-    for (unsigned Val : NonNull->args()) {
+    for (const ParamIdx &Idx : NonNull->args()) {
-      if (Val >= NumArgs)
+      unsigned IdxAST = Idx.getASTIndex();
+      if (IdxAST >= NumArgs)
         continue;
-      AttrNonNull.set(Val);
+      AttrNonNull.set(IdxAST);
     }
   }
   return AttrNonNull;

test/CodeGenCXX/alloc-size.cpp

@@ -86,3 +86,21 @@ int testIt() {
   return __builtin_object_size(p, 0);
 }
 } // namespace alloc_size_with_cleanups
+
+class C {
+public:
+  void *my_malloc(int N) __attribute__((alloc_size(2)));
+  void *my_calloc(int N, int M) __attribute__((alloc_size(2, 3)));
+};
+
+// CHECK-LABEL: define i32 @_Z16callMemberMallocv
+int callMemberMalloc() {
+  // CHECK: ret i32 16
+  return __builtin_object_size(C().my_malloc(16), 0);
+}
+
+// CHECK-LABEL: define i32 @_Z16callMemberCallocv
+int callMemberCalloc() {
+  // CHECK: ret i32 32
+  return __builtin_object_size(C().my_calloc(16, 2), 0);
+}

test/Frontend/ast-attr.cpp

@@ -0,0 +1,5 @@
+// RUN: %clang -emit-ast -o %t.ast %S/../Sema/attr-print.cpp
+// RUN: %clang_cc1 %t.ast -ast-print | FileCheck %S/../Sema/attr-print.cpp
+
+// %S/../Sema/attr-print.cpp exercises many different attributes, so we reuse
+// it here to check -emit-ast for attributes.

test/Misc/ast-dump-attr.cpp

@@ -68,12 +68,12 @@ __attribute__((pointer_with_type_tag(ident1,1,2)));
 void TestBool(void *, int)
 __attribute__((pointer_with_type_tag(bool1,1,2)));
 // CHECK: FunctionDecl{{.*}}TestBool
-// CHECK:   ArgumentWithTypeTagAttr{{.*}}pointer_with_type_tag bool1 0 1 IsPointer
+// CHECK:   ArgumentWithTypeTagAttr{{.*}}pointer_with_type_tag bool1 1 2 IsPointer
 
 void TestUnsigned(void *, int)
 __attribute__((pointer_with_type_tag(unsigned1,1,2)));
 // CHECK: FunctionDecl{{.*}}TestUnsigned
-// CHECK:   ArgumentWithTypeTagAttr{{.*}} pointer_with_type_tag unsigned1 0 1
+// CHECK:   ArgumentWithTypeTagAttr{{.*}} pointer_with_type_tag unsigned1 1 2
 
 void TestInt(void) __attribute__((constructor(123)));
 // CHECK:      FunctionDecl{{.*}}TestInt

test/Sema/attr-ownership.cpp

@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only
+
+class C {
+  void f(int, int)
+      __attribute__((ownership_returns(foo, 2)))  // expected-note {{declared with index 2 here}}
+      __attribute__((ownership_returns(foo, 3))); // expected-error {{'ownership_returns' attribute index does not match; here it is 3}}
+};

test/Sema/attr-print.cpp

@@ -1,6 +1,69 @@
 // RUN: %clang_cc1 %s -ast-print | FileCheck %s
 
+// This file is also used as input for %S/../Frontend/ast-attr.cpp.
+
+// CHECK: void xla(int a) __attribute__((xray_log_args(1)));
+void xla(int a) __attribute__((xray_log_args(1)));
+
 // CHECK: void *as2(int, int) __attribute__((alloc_size(1, 2)));
 void *as2(int, int) __attribute__((alloc_size(1, 2)));
 // CHECK: void *as1(void *, int) __attribute__((alloc_size(2)));
 void *as1(void *, int) __attribute__((alloc_size(2)));
+
+// CHECK: void fmt(int, const char *, ...) __attribute__((format(printf, 2, 3)));
+void fmt(int, const char *, ...) __attribute__((format(printf, 2, 3)));
+
+// CHECK: char *fmta(int, const char *) __attribute__((format_arg(2)));
+char *fmta(int, const char *) __attribute__((format_arg(2)));
+
+// CHECK: void nn(int *, int *) __attribute__((nonnull(1, 2)));
+void nn(int *, int *) __attribute__((nonnull(1, 2)));
+
+// CHECK: int *aa(int i) __attribute__((alloc_align(1)));
+int *aa(int i) __attribute__((alloc_align(1)));
+
+// CHECK: void ownt(int *, int *) __attribute__((ownership_takes(foo, 1, 2)));
+void ownt(int *, int *) __attribute__((ownership_takes(foo, 1, 2)));
+// CHECK: void ownh(int *, int *) __attribute__((ownership_holds(foo, 1, 2)));
+void ownh(int *, int *) __attribute__((ownership_holds(foo, 1, 2)));
+// CHECK: void ownr(int) __attribute__((ownership_returns(foo, 1)));
+void ownr(int) __attribute__((ownership_returns(foo, 1)));
+
+// CHECK: void awtt(int, int, ...) __attribute__((argument_with_type_tag(foo, 3, 2)));
+void awtt(int, int, ...) __attribute__((argument_with_type_tag(foo, 3, 2)));
+// CHECK: void pwtt(void *, int) __attribute__((pointer_with_type_tag(foo, 1, 2)));
+void pwtt(void *, int) __attribute__((pointer_with_type_tag(foo, 1, 2)));
+
+class C {
+  // CHECK: void xla(int a) __attribute__((xray_log_args(2)));
+  void xla(int a) __attribute__((xray_log_args(2)));
+
+  // CHECK: void *as2(int, int) __attribute__((alloc_size(2, 3)));
+  void *as2(int, int) __attribute__((alloc_size(2, 3)));
+  // CHECK: void *as1(void *, int) __attribute__((alloc_size(3)));
+  void *as1(void *, int) __attribute__((alloc_size(3)));
+
+  // CHECK: void fmt(int, const char *, ...) __attribute__((format(printf, 3, 4)));
+  void fmt(int, const char *, ...) __attribute__((format(printf, 3, 4)));
+
+  // CHECK: char *fmta(int, const char *) __attribute__((format_arg(3)));
+  char *fmta(int, const char *) __attribute__((format_arg(3)));
+
+  // CHECK: void nn(int *, int *) __attribute__((nonnull(2, 3)));
+  void nn(int *, int *) __attribute__((nonnull(2, 3)));
+
+  // CHECK: int *aa(int i) __attribute__((alloc_align(2)));
+  int *aa(int i) __attribute__((alloc_align(2)));
+
+  // CHECK: void ownt(int *, int *) __attribute__((ownership_takes(foo, 2, 3)));
+  void ownt(int *, int *) __attribute__((ownership_takes(foo, 2, 3)));
+  // CHECK: void ownh(int *, int *) __attribute__((ownership_holds(foo, 2, 3)));
+  void ownh(int *, int *) __attribute__((ownership_holds(foo, 2, 3)));
+  // CHECK: void ownr(int) __attribute__((ownership_returns(foo, 2)));
+  void ownr(int) __attribute__((ownership_returns(foo, 2)));
+
+  // CHECK: void awtt(int, int, ...) __attribute__((argument_with_type_tag(foo, 4, 3)));
+  void awtt(int, int, ...) __attribute__((argument_with_type_tag(foo, 4, 3)));
+  // CHECK: void pwtt(void *, int) __attribute__((pointer_with_type_tag(foo, 2, 3)));
+  void pwtt(void *, int) __attribute__((pointer_with_type_tag(foo, 2, 3)));
+};

test/Sema/error-type-safety.cpp

@@ -3,21 +3,50 @@
 #define INT_TAG 42
 
 static const int test_in
-  __attribute__((type_tag_for_datatype(test, int))) = INT_TAG;
+    __attribute__((type_tag_for_datatype(test, int))) = INT_TAG;
 
 // Argument index: 1, Type tag index: 2
 void test_bounds_index(...)
-  __attribute__((argument_with_type_tag(test, 1, 2)));
+    __attribute__((argument_with_type_tag(test, 1, 2)));
+
+// Argument index: 1, Type tag index: 2
+void test_bounds_index_ptr(void *, ...)
+    __attribute__((pointer_with_type_tag(test, 1, 2)));
 
 // Argument index: 3, Type tag index: 1
 void test_bounds_arg_index(...)
-  __attribute__((argument_with_type_tag(test, 3, 1)));
+    __attribute__((argument_with_type_tag(test, 3, 1)));
+
+class C {
+public:
+  // Argument index: 2, Type tag index: 3
+  void test_bounds_index(...)
+      __attribute__((argument_with_type_tag(test, 2, 3)));
+
+  // Argument index: 2, Type tag index: 3
+  void test_bounds_index_ptr(void *, ...)
+      __attribute__((pointer_with_type_tag(test, 2, 3)));
+
+  // Argument index: 4, Type tag index: 2
+  void test_bounds_arg_index(...)
+      __attribute__((argument_with_type_tag(test, 4, 2)));
+};
 
 void test_bounds()
 {
+  C c;
+
   // Test the boundary edges (ensure no off-by-one) with argument indexing.
   test_bounds_index(1, INT_TAG);
+  c.test_bounds_index(1, INT_TAG);
+  test_bounds_index_ptr(0, INT_TAG);
+  c.test_bounds_index_ptr(0, INT_TAG);
 
-  test_bounds_index(1); // expected-error {{type tag index 2 is greater than the number of arguments specified}}
+  test_bounds_index(1);       // expected-error {{type tag index 2 is greater than the number of arguments specified}}
-  test_bounds_arg_index(INT_TAG, 1); // expected-error {{argument index 3 is greater than the number of arguments specified}}
+  c.test_bounds_index(1);     // expected-error {{type tag index 3 is greater than the number of arguments specified}}
+  test_bounds_index_ptr(0);   // expected-error {{type tag index 2 is greater than the number of arguments specified}}
+  c.test_bounds_index_ptr(0); // expected-error {{type tag index 3 is greater than the number of arguments specified}}
+
+  test_bounds_arg_index(INT_TAG, 1);   // expected-error {{argument index 3 is greater than the number of arguments specified}}
+  c.test_bounds_arg_index(INT_TAG, 1); // expected-error {{argument index 4 is greater than the number of arguments specified}}
 }

utils/TableGen/ClangAttrEmitter.cpp

@@ -104,6 +104,7 @@ static std::string ReadPCHRecord(StringRef type) {
     .Case("Expr *", "Record.readExpr()")
     .Case("IdentifierInfo *", "Record.getIdentifierInfo()")
     .Case("StringRef", "Record.readString()")
+    .Case("ParamIdx", "ParamIdx::deserialize(Record.readInt())")
     .Default("Record.readInt()");
 }
 
@@ -122,6 +123,7 @@ static std::string WritePCHRecord(StringRef type, StringRef name) {
     .Case("Expr *", "AddStmt(" + std::string(name) + ");\n")
     .Case("IdentifierInfo *", "AddIdentifierRef(" + std::string(name) + ");\n")
     .Case("StringRef", "AddString(" + std::string(name) + ");\n")
+    .Case("ParamIdx", "push_back(" + std::string(name) + ".serialize());\n")
     .Default("push_back(" + std::string(name) + ");\n");
 }
 
@@ -302,9 +304,8 @@ namespace {
     std::string getIsOmitted() const override {
       if (type == "IdentifierInfo *")
         return "!get" + getUpperName().str() + "()";
-      // FIXME: Do this declaratively in Attr.td.
+      if (type == "ParamIdx")
-      if (getAttrName() == "AllocSize")
+        return "!get" + getUpperName().str() + "().isValid()";
-        return "0 == get" + getUpperName().str() + "()";
       return "false";
     }
 
@@ -319,6 +320,8 @@ namespace {
            << "()->getName() : \"\") << \"";
       else if (type == "TypeSourceInfo *")
         OS << "\" << get" << getUpperName() << "().getAsString() << \"";
+      else if (type == "ParamIdx")
+        OS << "\" << get" << getUpperName() << "().getSourceIndex() << \"";
       else
         OS << "\" << get" << getUpperName() << "() << \"";
     }
@@ -341,6 +344,11 @@ namespace {
            << getUpperName() << "\";\n";
       } else if (type == "int" || type == "unsigned") {
         OS << "    OS << \" \" << SA->get" << getUpperName() << "();\n";
+      } else if (type == "ParamIdx") {
+        if (isOptional())
+          OS << "    if (SA->get" << getUpperName() << "().isValid())\n  ";
+        OS << "    OS << \" \" << SA->get" << getUpperName()
+           << "().getSourceIndex();\n";
       } else {
         llvm_unreachable("Unknown SimpleArgument type!");
       }
@@ -618,6 +626,10 @@ namespace {
     virtual void writeValueImpl(raw_ostream &OS) const {
       OS << "    OS << Val;\n";
     }
+    // Assumed to receive a parameter: raw_ostream OS.
+    virtual void writeDumpImpl(raw_ostream &OS) const {
+      OS << "      OS << \" \" << Val;\n";
+    }
 
   public:
     VariadicArgument(const Record &Arg, StringRef Attr, std::string T)
@@ -744,7 +756,22 @@ namespace {
 
     void writeDump(raw_ostream &OS) const override {
       OS << "    for (const auto &Val : SA->" << RangeName << "())\n";
-      OS << "      OS << \" \" << Val;\n";
+      writeDumpImpl(OS);
+    }
+  };
+
+  class VariadicParamIdxArgument : public VariadicArgument {
+  public:
+    VariadicParamIdxArgument(const Record &Arg, StringRef Attr)
+        : VariadicArgument(Arg, Attr, "ParamIdx") {}
+
+  public:
+    void writeValueImpl(raw_ostream &OS) const override {
+      OS << "    OS << Val.getSourceIndex();\n";
+    }
+
+    void writeDumpImpl(raw_ostream &OS) const override {
+      OS << "      OS << \" \" << Val.getSourceIndex();\n";
     }
   };
 
@@ -1247,6 +1274,10 @@ createArgument(const Record &Arg, StringRef Attr,
     Ptr = llvm::make_unique<VariadicEnumArgument>(Arg, Attr);
   else if (ArgName == "VariadicExprArgument")
     Ptr = llvm::make_unique<VariadicExprArgument>(Arg, Attr);
+  else if (ArgName == "VariadicParamIdxArgument")
+    Ptr = llvm::make_unique<VariadicParamIdxArgument>(Arg, Attr);
+  else if (ArgName == "ParamIdxArgument")
+    Ptr = llvm::make_unique<SimpleArgument>(Arg, Attr, "ParamIdx");
   else if (ArgName == "VersionArgument")
     Ptr = llvm::make_unique<VersionArgument>(Arg, Attr);