[clang] [CIR] Upstream TypeInfo attribute (PR #159426)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Amr Hesham (AmrDeveloper)

<details>
<summary>Changes</summary>

This change adds support for TypeInfoAttr which is needed later for RTTI in exceptions

Issue https://github.com/llvm/llvm-project/issues/154992

---
Full diff: https://github.com/llvm/llvm-project/pull/159426.diff


4 Files Affected:

- (modified) clang/include/clang/CIR/Dialect/IR/CIRAttrs.td (+48) 
- (modified) clang/lib/CIR/Dialect/IR/CIRDialect.cpp (+21-2) 
- (modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+15) 
- (added) clang/test/CIR/IR/invalid-type-info.cir (+17) 


``````````diff
diff --git a/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td b/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
index 16b818f851e1c..10afd7133eed3 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
@@ -779,4 +779,52 @@ def CIR_AddressPointAttr : CIR_Attr<"AddressPoint", "address_point"> {
   }];
 }
 
+//===----------------------------------------------------------------------===//
+// TypeInfoAttr
+//===----------------------------------------------------------------------===//
+
+def CIR_TypeInfoAttr : CIR_Attr<"TypeInfo", "typeinfo", [TypedAttrInterface]> {
+  let summary = "Represents a typeinfo used for RTTI";
+  let description = [{
+    The typeinfo data for a given class is stored into an ArrayAttr. The
+    layout is determined by the C++ ABI used (clang only implements
+    itanium on CIRGen).
+
+    The verifier enforces that the output type is always a `!cir.record`,
+    and that the ArrayAttr element types match the equivalent member type
+    for the resulting record, i.e, a GlobalViewAttr for symbol reference or
+    an IntAttr for flags.
+
+    Example:
+
+    ```
+    cir.global "private" external @_ZTVN10__cxxabiv120__si_class_type_infoE : !cir.ptr<i32>
+
+    !rec_anon_struct = !cir.record<struct  {!cir.ptr<!u8i>, !cir.ptr<!u8i>, !cir.ptr<!u8i>}>
+
+    cir.global constant external @type_info = #cir.typeinfo<{
+      #cir.global_view<@_ZTVN10__cxxabiv120__si_class_type_infoE, [2 : i32]>
+      : !cir.ptr<!u8i>, #cir.global_view<@_ZTS1B> : !cir.ptr<!u8i>, #cir.global_view<@_ZTI1A>
+      : !cir.ptr<!u8i>}> : !rec_anon_struct
+    ```
+  }];
+
+  let parameters = (ins AttributeSelfTypeParameter<"">:$type,
+                        "mlir::ArrayAttr":$data);
+
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "mlir::Type":$type,
+                                        "mlir::ArrayAttr":$data), [{
+      return $_get(type.getContext(), type, data);
+    }]>
+  ];
+
+  // Checks record element types should match the array for every equivalent
+  // element type.
+  let genVerifyDecl = 1;
+  let assemblyFormat = [{
+    `<` custom<RecordMembers>($data) `>`
+  }];
+}
+
 #endif // CLANG_CIR_DIALECT_IR_CIRATTRS_TD
diff --git a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
index 8918eb4cbb1ad..3fcc0aad9b11b 100644
--- a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
+++ b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
@@ -342,8 +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, cir::VTableAttr>(
-          attrType))
+                cir::GlobalViewAttr, cir::PoisonAttr, cir::TypeInfoAttr,
+                cir::VTableAttr>(attrType))
     return success();
 
   assert(isa<TypedAttr>(attrType) && "What else could we be looking at here?");
@@ -2741,6 +2741,25 @@ LogicalResult cir::AtomicCmpXchg::verify() {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// TypeInfoAttr
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::TypeInfoAttr::verify(
+    ::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError,
+    ::mlir::Type type, ::mlir::ArrayAttr typeinfoData) {
+
+  if (cir::ConstRecordAttr::verify(emitError, type, typeinfoData).failed())
+    return failure();
+
+  for (auto &member : typeinfoData) {
+    if (llvm::isa<GlobalViewAttr, IntAttr>(member))
+      continue;
+    return emitError() << "expected GlobalViewAttr or IntAttr attribute";
+  }
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // TableGen'd op method definitions
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 1d7e3df1430ac..0c0c28a5cc379 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -235,6 +235,7 @@ class CIRAttrToValue {
   mlir::Value visitCirAttr(cir::ConstRecordAttr attr);
   mlir::Value visitCirAttr(cir::ConstVectorAttr attr);
   mlir::Value visitCirAttr(cir::GlobalViewAttr attr);
+  mlir::Value visitCirAttr(cir::TypeInfoAttr attr);
   mlir::Value visitCirAttr(cir::VTableAttr attr);
   mlir::Value visitCirAttr(cir::ZeroAttr attr);
 
@@ -521,6 +522,20 @@ mlir::Value CIRAttrToValue::visitCirAttr(cir::GlobalViewAttr globalAttr) {
   llvm_unreachable("Expecting pointer or integer type for GlobalViewAttr");
 }
 
+// TypeInfoAttr visitor.
+mlir::Value CIRAttrToValue::visitCirAttr(cir::TypeInfoAttr typeinfoArr) {
+  mlir::Type llvmTy = converter->convertType(typeinfoArr.getType());
+  mlir::Location loc = parentOp->getLoc();
+  mlir::Value result = rewriter.create<mlir::LLVM::UndefOp>(loc, llvmTy);
+
+  for (auto [idx, elt] : llvm::enumerate(typeinfoArr.getData())) {
+    mlir::Value init = visit(elt);
+    result = rewriter.create<mlir::LLVM::InsertValueOp>(loc, result, init, idx);
+  }
+
+  return result;
+}
+
 // VTableAttr visitor.
 mlir::Value CIRAttrToValue::visitCirAttr(cir::VTableAttr vtableArr) {
   mlir::Type llvmTy = converter->convertType(vtableArr.getType());
diff --git a/clang/test/CIR/IR/invalid-type-info.cir b/clang/test/CIR/IR/invalid-type-info.cir
new file mode 100644
index 0000000000000..9a6c0d7234021
--- /dev/null
+++ b/clang/test/CIR/IR/invalid-type-info.cir
@@ -0,0 +1,17 @@
+// RUN: cir-opt %s -verify-diagnostics -split-input-file
+
+!u8i = !cir.int<u, 8>
+
+!rec_anon_struct = !cir.record<struct  {!cir.ptr<!u8i>, !cir.ptr<!u8i>, !cir.ptr<!u8i>}>
+
+// expected-error @below {{expected !cir.record type}}
+cir.global constant external @type_info = #cir.typeinfo<{#cir.global_view<@_ZTVN10__cxxabiv120__si_class_type_infoE, [2 : i32]> : !cir.ptr<!u8i>, #cir.global_view<@_ZTS1B> : !cir.ptr<!u8i>, #cir.global_view<@_ZTI1A> : !cir.ptr<!u8i>}> : !u8i
+
+// -----
+
+!u8i = !cir.int<u, 8>
+
+!rec_anon_struct = !cir.record<struct  {!u8i, !u8i, !u8i}>
+
+// expected-error @below {{expected GlobalViewAttr or IntAttr attribute}}
+cir.global constant external @type_info = #cir.typeinfo<{ #cir.undef : !u8i, #cir.int<1> : !u8i, #cir.int<1> : !u8i}> : !rec_anon_struct

``````````

</details>


https://github.com/llvm/llvm-project/pull/159426