[CIR] Make AST attributes accessible via interfaces. (#250)

- Introduces `CIR/Interfaces/ASTAttrInterfaces` which model API of clang
AST nodes, but allows to plugin custom attribute, making `CIR` dialect
AST independent.

- Extends hierarchy of `DeclAttr`s to model `Decl` attributes more
faithfully.
- Notably all `CIRASTAttr`s are now created uniformly using
`makeAstDeclAttr` which builds corresponding Attribute based on
`clang::Decl`.

Author: xlauko

clang/include/clang/CIR/CMakeLists.txt

@@ -1,6 +1,8 @@
+set(MLIR_MAIN_SRC_DIR ${LLVM_MAIN_SRC_DIR}/../mlir/include ) # --src-root
 set(MLIR_INCLUDE_DIR ${LLVM_MAIN_SRC_DIR}/../mlir/include ) # --includedir
 set(MLIR_TABLEGEN_OUTPUT_DIR ${CMAKE_BINARY_DIR}/tools/mlir/include)
-include_directories(${MLIR_INCLUDE_DIR})
-include_directories(${MLIR_TABLEGEN_OUTPUT_DIR})
+include_directories(SYSTEM ${MLIR_INCLUDE_DIR})
+include_directories(SYSTEM ${MLIR_TABLEGEN_OUTPUT_DIR})
 
 add_subdirectory(Dialect)
+add_subdirectory(Interfaces)

clang/include/clang/CIR/Dialect/CMakeLists.txt

@@ -1,9 +1,3 @@
-set(MLIR_MAIN_SRC_DIR ${LLVM_MAIN_SRC_DIR}/../mlir/include ) # --src-root
-set(MLIR_INCLUDE_DIR ${LLVM_MAIN_SRC_DIR}/../mlir/include ) # --includedir
-set(MLIR_TABLEGEN_OUTPUT_DIR ${CMAKE_BINARY_DIR}/tools/mlir/include)
-include_directories(SYSTEM ${MLIR_INCLUDE_DIR})
-include_directories(SYSTEM ${MLIR_TABLEGEN_OUTPUT_DIR})
-
 add_custom_target(clang-cir-doc)
 
 # This replicates part of the add_mlir_doc cmake function from MLIR that cannot

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

@@ -19,8 +19,12 @@
 #include "mlir/IR/Attributes.h"
 #include "mlir/IR/BuiltinAttributeInterfaces.h"
 
+#include "llvm/ADT/SmallVector.h"
+
 #include "clang/CIR/Dialect/IR/CIROpsEnums.h"
 
+#include "clang/CIR/Interfaces/ASTAttrInterfaces.h"
+
 //===----------------------------------------------------------------------===//
 // CIR Dialect Attrs
 //===----------------------------------------------------------------------===//

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

@@ -15,8 +15,11 @@
 
 include "mlir/IR/BuiltinAttributeInterfaces.td"
 include "mlir/IR/EnumAttr.td"
+
 include "clang/CIR/Dialect/IR/CIRDialect.td"
 
+include "clang/CIR/Interfaces/ASTAttrInterfaces.td"
+
 //===----------------------------------------------------------------------===//
 // CIR Attrs
 //===----------------------------------------------------------------------===//
@@ -394,12 +397,55 @@ class ASTDecl<string name, string prefix, list<Trait> traits = []>
 
   // Enable verifier.
   let genVerifyDecl = 1;
+
+  let extraClassDefinition = [{
+    ::mlir::Attribute $cppClass::parse(::mlir::AsmParser &parser,
+                                       ::mlir::Type type) {
+      // We cannot really parse anything AST related at this point
+      // since we have no serialization/JSON story.
+      return $cppClass::get(parser.getContext(), nullptr);
+    }
+
+    void $cppClass::print(::mlir::AsmPrinter &printer) const {
+      // Nothing to print besides the mnemonics.
+    }
+
+    LogicalResult $cppClass::verify(
+        ::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError,
+        }] # clang_name # [{ decl) {
+      return success();
+    }
+  }];
 }
 
-def ASTFunctionDeclAttr : ASTDecl<"FunctionDecl", "fndecl">;
-def ASTVarDeclAttr : ASTDecl<"VarDecl", "vardecl">;
-def ASTRecordDeclAttr : ASTDecl<"RecordDecl", "recdecl">;
+def ASTDeclAttr : ASTDecl<"Decl", "decl", [ASTDeclInterface]>;
+
+def ASTFunctionDeclAttr : ASTDecl<"FunctionDecl", "function.decl",
+  [ASTFunctionDeclInterface]>;
+
+def ASTCXXMethodDeclAttr : ASTDecl<"CXXMethodDecl", "cxxmethod.decl",
+  [ASTCXXMethodDeclInterface]>;
+
+def ASTCXXConstructorDeclAttr : ASTDecl<"CXXConstructorDecl",
+  "cxxconstructor.decl", [ASTCXXConstructorDeclInterface]>;
+
+def ASTCXXConversionDeclAttr : ASTDecl<"CXXConversionDecl",
+  "cxxconversion.decl", [ASTCXXConversionDeclInterface]>;
+
+def ASTCXXDestructorDeclAttr : ASTDecl<"CXXDestructorDecl",
+  "cxxdestructor.decl", [ASTCXXDestructorDeclInterface]>;
+
+def ASTVarDeclAttr : ASTDecl<"VarDecl", "var.decl",
+  [ASTVarDeclInterface]>;
+
+def ASTTypeDeclAttr: ASTDecl<"TypeDecl", "type.decl",
+  [ASTTypeDeclInterface]>;
+
+def ASTTagDeclAttr : ASTDecl<"TagDecl", "tag.decl",
+  [ASTTagDeclInterface]>;
 
+def ASTRecordDeclAttr : ASTDecl<"RecordDecl", "record.decl",
+  [ASTRecordDeclInterface]>;
 
 //===----------------------------------------------------------------------===//
 // ExtraFuncAttr

clang/include/clang/CIR/Dialect/IR/CIRDialect.h

@@ -31,6 +31,8 @@
 #include "clang/CIR/Dialect/IR/CIROpsStructs.h.inc"
 #include "clang/CIR/Dialect/IR/CIRTypes.h"
 
+#include "clang/CIR/Interfaces/ASTAttrInterfaces.h"
+
 namespace mlir {
 namespace OpTrait {
 

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

@@ -18,6 +18,8 @@ include "clang/CIR/Dialect/IR/CIRDialect.td"
 include "clang/CIR/Dialect/IR/CIRTypes.td"
 include "clang/CIR/Dialect/IR/CIRAttrs.td"
 
+include "clang/CIR/Interfaces/ASTAttrInterfaces.td"
+
 include "mlir/Interfaces/CallInterfaces.td"
 include "mlir/Interfaces/ControlFlowInterfaces.td"
 include "mlir/Interfaces/FunctionInterfaces.td"
@@ -300,7 +302,7 @@ def AllocaOp : CIR_Op<"alloca", [
     StrAttr:$name,
     UnitAttr:$init,
     ConfinedAttr<OptionalAttr<I64Attr>, [IntMinValue<0>]>:$alignment,
-    OptionalAttr<ASTVarDeclAttr>:$ast
+    OptionalAttr<ASTVarDeclInterface>:$ast
   );
 
   let results = (outs Res<CIR_PointerType, "",
@@ -1283,7 +1285,7 @@ def GlobalOp : CIR_Op<"global", [Symbol, DeclareOpInterfaceMethods<RegionBranchO
                        OptionalAttr<AnyAttr>:$initial_value,
                        UnitAttr:$constant,
                        OptionalAttr<I64Attr>:$alignment,
-                       OptionalAttr<ASTVarDeclAttr>:$ast
+                       OptionalAttr<ASTVarDeclInterface>:$ast
                        );
   let regions = (region AnyRegion:$ctorRegion, AnyRegion:$dtorRegion);
   let assemblyFormat = [{
@@ -1596,7 +1598,7 @@ def FuncOp : CIR_Op<"func", [
                        OptionalAttr<DictArrayAttr>:$arg_attrs,
                        OptionalAttr<DictArrayAttr>:$res_attrs,
                        OptionalAttr<FlatSymbolRefAttr>:$aliasee,
-                       OptionalAttr<ASTFunctionDeclAttr>:$ast);
+                       OptionalAttr<AnyASTFunctionDeclAttr>:$ast);
   let regions = (region AnyRegion:$body);
   let skipDefaultBuilders = 1;
 

clang/include/clang/CIR/Dialect/IR/CIRTypes.h

@@ -17,16 +17,12 @@
 #include "mlir/IR/Types.h"
 #include "mlir/Interfaces/DataLayoutInterfaces.h"
 
+#include "clang/CIR/Interfaces/ASTAttrInterfaces.h"
+
 //===----------------------------------------------------------------------===//
 // CIR Dialect Types
 //===----------------------------------------------------------------------===//
 
-namespace mlir {
-namespace cir {
-class ASTRecordDeclAttr;
-} // namespace cir
-} // namespace mlir
-
 #define GET_TYPEDEF_CLASSES
 #include "clang/CIR/Dialect/IR/CIROpsTypes.h.inc"
 

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

@@ -14,6 +14,7 @@
 #define MLIR_CIR_DIALECT_CIR_TYPES
 
 include "clang/CIR/Dialect/IR/CIRDialect.td"
+include "clang/CIR/Interfaces/ASTAttrInterfaces.td"
 include "mlir/Interfaces/DataLayoutInterfaces.td"
 include "mlir/IR/AttrTypeBase.td"
 
@@ -111,7 +112,7 @@ def CIR_StructType : CIR_Type<"Struct", "struct",
     "bool":$body,
     "bool":$packed,
     "mlir::cir::StructType::RecordKind":$kind,
-    "std::optional<::mlir::cir::ASTRecordDeclAttr>":$ast
+    "std::optional<ASTRecordDeclInterface>":$ast
   );
 
   let hasCustomAssemblyFormat = 1;

clang/include/clang/CIR/Interfaces/ASTAttrInterfaces.h

@@ -0,0 +1,45 @@
+//===- ASTAttrInterfaces.h - CIR AST Interfaces -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_INTERFACES_CIR_AST_ATTR_INTERFACES_H_
+#define MLIR_INTERFACES_CIR_AST_ATTR_INTERFACES_H_
+
+#include "mlir/IR/Attributes.h"
+
+#include "clang/AST/Attr.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/Mangle.h"
+
+namespace mlir {
+namespace cir {
+
+mlir::Attribute makeFuncDeclAttr(const clang::Decl *decl,
+                                 mlir::MLIRContext *ctx);
+
+} // namespace cir
+} // namespace mlir
+
+/// Include the generated interface declarations.
+#include "clang/CIR/Interfaces/ASTAttrInterfaces.h.inc"
+
+namespace mlir {
+namespace cir {
+
+template <typename T> bool hasAttr(ASTDeclInterface decl) {
+  if constexpr (std::is_same_v<T, clang::OwnerAttr>)
+    return decl.hasOwnerAttr();
+  if constexpr (std::is_same_v<T, clang::PointerAttr>)
+    return decl.hasPointerAttr();
+  if constexpr (std::is_same_v<T, clang::InitPriorityAttr>)
+    return decl.hasInitPriorityAttr();
+}
+
+} // namespace cir
+} // namespace mlir
+
+#endif // MLIR_INTERFACES_CIR_AST_ATAR_INTERFACES_H_