[TableGen] Allow intrinsics to have up to 8 return values.

[tra]

Summary

The change is needed for my upcoming changes to NVPTX back-end that implement an intrinsic that has up to 8 output values.

[jlebar]

llvm/lib/IR/Function.cpp

655

Is there a reason not to put these consecutive with struct5?

[tra]

llvm/lib/IR/Function.cpp

655

Caution mostly. If enum has explicitly assigned values, I assume that someone somewhere relies on them being exactly those values and it's prudent to extend the range rather than change existing order.

[tra]

Fixed another place where we're checking the number of fields in a struct.

[tra]

Ugh. Make sure static array to keep per-field info is also sized properly.

[tra]

Replaced fixed-size array with SmallVector<>. One less place for making potential buffer overflow error when struct encoding changes.

[rnk]

Looks good!

llvm/lib/IR/Function.cpp

enum IIT_Info {
   IIT_VARARG = 29,
   IIT_HALF_VEC_ARG = 30,
   IIT_SAME_VEC_WIDTH_ARG = 31,
   IIT_PTR_TO_ARG = 32,
   IIT_PTR_TO_ELT = 33,
   IIT_VEC_OF_ANYPTRS_TO_ELT = 34,
   IIT_I128 = 35,
   IIT_V512 = 36,
-  IIT_V1024 = 37
+  IIT_V1024 = 37,
+  IIT_STRUCT6 = 38,
+  IIT_STRUCT7 = 39,
+  IIT_STRUCT8 = 40
 };
 
 static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
                       SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
   using namespace Intrinsic;
 
   IIT_Info Info = IIT_Info(Infos[NextElt++]);
   unsigned StructElts = 2;
case IIT_VEC_OF_ANYPTRS_TO_ELT: {
     unsigned short RefNo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
     OutputTable.push_back(
         IITDescriptor::get(IITDescriptor::VecOfAnyPtrsToElt, ArgNo, RefNo));
     return;
   }
   case IIT_EMPTYSTRUCT:
     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
     return;
+  case IIT_STRUCT8: ++StructElts; LLVM_FALLTHROUGH;
+  case IIT_STRUCT7: ++StructElts; LLVM_FALLTHROUGH;
+  case IIT_STRUCT6: ++StructElts; LLVM_FALLTHROUGH;
   case IIT_STRUCT5: ++StructElts; LLVM_FALLTHROUGH;
   case IIT_STRUCT4: ++StructElts; LLVM_FALLTHROUGH;
   case IIT_STRUCT3: ++StructElts; LLVM_FALLTHROUGH;
   case IIT_STRUCT2: {
     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
 
     for (unsigned i = 0; i != StructElts; ++i)
       DecodeIITType(NextElt, Infos, OutputTable);
case IITDescriptor::Integer:
     return IntegerType::get(Context, D.Integer_Width);
   case IITDescriptor::Vector:
     return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
   case IITDescriptor::Pointer:
     return PointerType::get(DecodeFixedType(Infos, Tys, Context),
                             D.Pointer_AddressSpace);
   case IITDescriptor::Struct: {
     Type *Elts[5];
-    assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
+    assert(D.Struct_NumElements <= 8 && "Can't handle this yet");
     for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
       Elts[i] = DecodeFixedType(Infos, Tys, Context);
     return StructType::get(Context, makeArrayRef(Elts,D.Struct_NumElements));
   }
   case IITDescriptor::Argument:
     return Tys[D.getArgumentNumber()];
   case IITDescriptor::ExtendArgument: {
     Type *Ty = Tys[D.getArgumentNumber()];

llvm/test/TableGen/intrinsic-struct.td

+// RUN: llvm-tblgen -gen-intrinsic %s | FileCheck %s
+// XFAIL: vg_leak
+
+class IntrinsicProperty;
+
+class ValueType<int size, int value> {
+  string Namespace = "MVT";
+  int Size = size;
+  int Value = value;
+}
+
+class LLVMType<ValueType vt> {
+  ValueType VT = vt;
+}
+
+class Intrinsic<string name, list<LLVMType> ret_types = []> {
+  string LLVMName = name;
+  bit isTarget = 0;
+  string TargetPrefix = "";
+  list<LLVMType> RetTypes = ret_types;
+  list<LLVMType> ParamTypes = [];
+  list<IntrinsicProperty> IntrProperties = [];
+}
+
+def iAny : ValueType<0, 253>;
+def llvm_anyint_ty : LLVMType<iAny>;
+
+// Make sure we can return up to 8 values
+// CHECK: returns_8_results // llvm.returns.8.results
+def int_returns_8_results : Intrinsic<"llvm.returns.8.results",
+    [llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty,
+     llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty, llvm_anyint_ty]>;

llvm/utils/TableGen/IntrinsicEmitter.cpp

enum IIT_Info {
   IIT_VARARG = 29,
   IIT_HALF_VEC_ARG = 30,
   IIT_SAME_VEC_WIDTH_ARG = 31,
   IIT_PTR_TO_ARG = 32,
   IIT_PTR_TO_ELT = 33,
   IIT_VEC_OF_ANYPTRS_TO_ELT = 34,
   IIT_I128 = 35,
   IIT_V512 = 36,
-  IIT_V1024 = 37
+  IIT_V1024 = 37,
+  IIT_STRUCT6 = 38,
+  IIT_STRUCT7 = 39,
+  IIT_STRUCT8 = 40
 };
 
 static void EncodeFixedValueType(MVT::SimpleValueType VT,
                                  std::vector<unsigned char> &Sig) {
   if (MVT(VT).isInteger()) {
     unsigned BitWidth = MVT(VT).getSizeInBits();
     switch (BitWidth) {
     default: PrintFatalError("unhandled integer type width in intrinsic!");
else if (Int.IS.RetVTs.size() == 1 &&
     TypeSig.push_back(IIT_Done);
   else {
     switch (Int.IS.RetVTs.size()) {
       case 1: break;
       case 2: TypeSig.push_back(IIT_STRUCT2); break;
       case 3: TypeSig.push_back(IIT_STRUCT3); break;
       case 4: TypeSig.push_back(IIT_STRUCT4); break;
       case 5: TypeSig.push_back(IIT_STRUCT5); break;
+      case 6: TypeSig.push_back(IIT_STRUCT6); break;
+      case 7: TypeSig.push_back(IIT_STRUCT7); break;
+      case 8: TypeSig.push_back(IIT_STRUCT8); break;
       default: llvm_unreachable("Unhandled case in struct");
     }
 
     for (unsigned i = 0, e = Int.IS.RetVTs.size(); i != e; ++i)
       EncodeFixedType(Int.IS.RetTypeDefs[i], ArgCodes, TypeSig);
   }
 
   for (unsigned i = 0, e = Int.IS.ParamTypeDefs.size(); i != e; ++i)