[CIR] Add CIR vtable attribute

clang/include/clang/CIR/Dialect/IR/CIRAttrs.td

@@ -496,6 +496,46 @@ def CIR_GlobalViewAttr : CIR_Attr<"GlobalView", "global_view", [
   }];
 }
 
+//===----------------------------------------------------------------------===//
+// VTableAttr
+//===----------------------------------------------------------------------===//
+
+def VTableAttr : CIR_Attr<"VTable", "vtable", [TypedAttrInterface]> {
+  let summary = "Represents a C++ vtable";
+  let description = [{
+    Wraps a #cir.const_record containing vtable data.
+
+    Example:
+    ```
+    cir.global linkonce_odr @_ZTV1B = #cir.vtable<<
+        {#cir.const_array<[#cir.null : !cir.ptr<i8>,
+         #cir.global_view<@_ZTI1B> : !cir.ptr<i8>,
+         #cir.global_view<@_ZN1BD1Ev> : !cir.ptr<i8>,
+         #cir.global_view<@_ZN1BD0Ev> : !cir.ptr<i8>,
+         #cir.global_view<@_ZNK1A5quackEv> : !cir.ptr<i8>]>
+         : !cir.array<!cir.ptr<i8> x 5>}>>
+      : !cir.record<"", !cir.array<!cir.ptr<i8> x 5>>
+    ```
+  }];
+
+  // `vtable_data` is a const record with one element, containing an array of
+  // vtable information.
+  let parameters = (ins AttributeSelfTypeParameter<"">:$type,
+                        "mlir::ArrayAttr":$vtable_data);
+
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "mlir::Type":$type,
+                                        "mlir::ArrayAttr":$vtable_data), [{
+      return $_get(type.getContext(), type, vtable_data);
+    }]>
+  ];
+
+  let genVerifyDecl = 1;
+  let assemblyFormat = [{
+    `<` custom<RecordMembers>($vtable_data) `>`
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // ConstComplexAttr
 //===----------------------------------------------------------------------===//

clang/lib/CIR/Dialect/IR/CIRAttrs.cpp

@@ -424,6 +424,44 @@ cir::ConstVectorAttr::verify(function_ref<InFlightDiagnostic()> emitError,
   return elementTypeCheck;
 }
 
+//===----------------------------------------------------------------------===//
+// CIR VTableAttr
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::VTableAttr::verify(
+    llvm::function_ref<mlir::InFlightDiagnostic()> emitError, mlir::Type type,
+    mlir::ArrayAttr vtableData) {
+  auto sTy = mlir::dyn_cast_if_present<cir::RecordType>(type);
+  if (!sTy)
+    return emitError() << "expected !cir.record type result";
+  if (sTy.getMembers().empty() || vtableData.empty())
+    return emitError() << "expected record type with one or more subtype";
+
+  for (size_t i = 0; i < sTy.getMembers().size(); ++i) {
+    auto constArrayAttr = mlir::dyn_cast<cir::ConstArrayAttr>(vtableData[i]);
+    if (!constArrayAttr)
+      return emitError() << "expected constant array subtype";
+
+    if (cir::ConstRecordAttr::verify(emitError, type, vtableData).failed())
+      return failure();
+
+    LogicalResult eltTypeCheck = success();
+    auto arrayElts = mlir::cast<ArrayAttr>(constArrayAttr.getElts());
+    arrayElts.walkImmediateSubElements(
+        [&](Attribute attr) {
+          if (mlir::isa<ConstPtrAttr, GlobalViewAttr>(attr))
+            return;
+
+          eltTypeCheck = emitError()
+                         << "expected GlobalViewAttr or ConstPtrAttr";
+        },
+        [&](Type type) {});
+    if (eltTypeCheck.failed())
+      return eltTypeCheck;
+  }
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // CIR Dialect
 //===----------------------------------------------------------------------===//

clang/lib/CIR/Dialect/IR/CIRDialect.cpp

@@ -342,7 +342,8 @@ static LogicalResult checkConstantTypes(mlir::Operation *op, mlir::Type opType,
 
   if (mlir::isa<cir::ConstArrayAttr, cir::ConstVectorAttr,
                 cir::ConstComplexAttr, cir::ConstRecordAttr,
-                cir::GlobalViewAttr, cir::PoisonAttr>(attrType))
+                cir::GlobalViewAttr, cir::PoisonAttr, cir::VTableAttr>(
+          attrType))
     return success();
 
   assert(isa<TypedAttr>(attrType) && "What else could we be looking at here?");

clang/test/CIR/IR/invalid-vtable.cir

@@ -1,4 +1,4 @@
-// RUN: cir-opt %s -verify-diagnostics
+// RUN: cir-opt %s -verify-diagnostics -split-input-file
 
 !s8i = !cir.int<s, 8>
 !u32i = !cir.int<u, 32>
@@ -7,3 +7,51 @@ cir.func @reference_unknown_vtable() {
   %0 = cir.vtable.address_point(@some_vtable, address_point = <index = 0, offset = 2>) : !cir.vptr
   cir.return
 }
+
+// -----
+
+!rec_S = !cir.record<struct "S" {!cir.vptr}>
+!u8i = !cir.int<u, 8>
+!rec_anon_struct = !cir.record<struct {!cir.array<!cir.ptr<!u8i> x 4>}>
+module {
+  // expected-error @below {{expected !cir.record type result}}
+  cir.global external @_ZTV1S = #cir.vtable<{#cir.const_array<[#cir.ptr<null> : !cir.ptr<!u8i>, #cir.ptr<null> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S3keyEv> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S6nonKeyEv> : !cir.ptr<!u8i>]> : !cir.array<!cir.ptr<!u8i> x 4>}> : !cir.ptr<!rec_anon_struct>
+  cir.func private dso_local @_ZN1S3keyEv(%arg0: !cir.ptr<!rec_S>)
+  cir.func private dso_local @_ZN1S6nonKeyEv(%arg0: !cir.ptr<!rec_S>)
+}
+
+// -----
+
+!rec_S = !cir.record<struct "S" {!cir.vptr}>
+!u8i = !cir.int<u, 8>
+!rec_anon_struct = !cir.record<struct  {}>
+module {
+  // expected-error @below {{expected record type with one or more subtype}}
+  cir.global external @_ZTV1S = #cir.vtable<{}> : !rec_anon_struct {alignment = 8 : i64}
+  cir.func private dso_local @_ZN1S3keyEv(%arg0: !cir.ptr<!rec_S>)
+  cir.func private dso_local @_ZN1S6nonKeyEv(%arg0: !cir.ptr<!rec_S>)
+}
+
+// -----
+
+!rec_S = !cir.record<struct "S" {!cir.vptr}>
+!u8i = !cir.int<u, 8>
+!rec_anon_struct = !cir.record<struct  {!cir.ptr<!u8i>}>
+module {
+  // expected-error @below {{expected constant array subtype}}
+  cir.global external @_ZTV1S = #cir.vtable<{#cir.ptr<null> : !cir.ptr<!u8i>}> : !rec_anon_struct {alignment = 8 : i64}
+  cir.func private dso_local @_ZN1S3keyEv(%arg0: !cir.ptr<!rec_S>)
+  cir.func private dso_local @_ZN1S6nonKeyEv(%arg0: !cir.ptr<!rec_S>)
+}
+
+// -----
+
+!rec_S = !cir.record<struct "S" {!cir.vptr}>
+!u64i = !cir.int<u, 64>
+!rec_anon_struct = !cir.record<struct  {!cir.array<!u64i x 4>}>
+module {
+  // expected-error @below {{expected GlobalViewAttr or ConstPtrAttr}}
+  cir.global external @_ZTV1S = #cir.vtable<{#cir.const_array<[#cir.int<1> : !u64i, #cir.int<1> : !u64i, #cir.int<3> : !u64i, #cir.int<4> : !u64i]> : !cir.array<!u64i x 4>}> : !rec_anon_struct {alignment = 8 : i64}
+  cir.func private dso_local @_ZN1S3keyEv(%arg0: !cir.ptr<!rec_S>)
+  cir.func private dso_local @_ZN1S6nonKeyEv(%arg0: !cir.ptr<!rec_S>)
+}

clang/test/CIR/IR/vtable-attr.cir

@@ -0,0 +1,12 @@
+// RUN: cir-opt %s | FileCheck %s
+
+!rec_S = !cir.record<struct "S" {!cir.vptr}>
+!u8i = !cir.int<u, 8>
+!rec_anon_struct = !cir.record<struct  {!cir.array<!cir.ptr<!u8i> x 4>}>
+module {
+  cir.global external @_ZTV1S = #cir.vtable<{#cir.const_array<[#cir.ptr<null> : !cir.ptr<!u8i>, #cir.ptr<null> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S3keyEv> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S6nonKeyEv> : !cir.ptr<!u8i>]> : !cir.array<!cir.ptr<!u8i> x 4>}> : !rec_anon_struct {alignment = 8 : i64}
+  // CHECK: cir.global external @_ZTV1S = #cir.vtable<{#cir.const_array<[#cir.ptr<null> : !cir.ptr<!u8i>, #cir.ptr<null> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S3keyEv> : !cir.ptr<!u8i>, #cir.global_view<@_ZN1S6nonKeyEv> : !cir.ptr<!u8i>]> : !cir.array<!cir.ptr<!u8i> x 4>}> : !rec_anon_struct {alignment = 8 : i64}
+
+  cir.func private dso_local @_ZN1S3keyEv(%arg0: !cir.ptr<!rec_S>)
+  cir.func private dso_local @_ZN1S6nonKeyEv(%arg0: !cir.ptr<!rec_S>)
+}