[CIR] Start printing/parsing func 'attributes' (#169674)

This patch adds a print and parse ability for the func to have
MLIR-standard 'attributes' printed along side the standard function.

This patch also seeds the initial "disallowed" list so that we don't
print things that we have custom printing for, AND will disallow them
from being parsed. I believe this list to be complete, and it passes all
tests.

This printing of attributes is necessary for testing some OpenACC things
that putting into the normal func-printing seems unnecessary.

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

@@ -1920,6 +1920,20 @@ ParseResult cir::FuncOp::parse(OpAsmParser &parser, OperationState &state) {
       return failure();
   }
 
+  // Parse the rest of the attributes.
+  NamedAttrList parsedAttrs;
+  if (parser.parseOptionalAttrDictWithKeyword(parsedAttrs))
+    return failure();
+
+  for (StringRef disallowed : cir::FuncOp::getAttributeNames()) {
+    if (parsedAttrs.get(disallowed))
+      return parser.emitError(loc, "attribute '")
+             << disallowed
+             << "' should not be specified in the explicit attribute list";
+  }
+
+  state.attributes.append(parsedAttrs);
+
   // Parse the optional function body.
   auto *body = state.addRegion();
   OptionalParseResult parseResult = parser.parseOptionalRegion(
@@ -2073,6 +2087,9 @@ void cir::FuncOp::print(OpAsmPrinter &p) {
     p << " inline(" << cir::stringifyInlineKind(inlineAttr.getValue()) << ")";
   }
 
+  function_interface_impl::printFunctionAttributes(
+      p, *this, cir::FuncOp::getAttributeNames());
+
   // Print the body if this is not an external function.
   Region &body = getOperation()->getRegion(0);
   if (!body.empty()) {

clang/test/CIR/IR/func.cir

@@ -186,3 +186,11 @@ cir.func @Foo_move_assign() special_member<#cir.cxx_assign<!rec_Foo, move>> {
 // CHECK: cir.func @Foo_move_assign() special_member<#cir.cxx_assign<!rec_Foo, move>> {
 // CHECK:   cir.return
 // CHECK: }
+
+cir.func @has_attrs() attributes {foo, baz = 5, floof = "flop"} {
+  cir.return
+}
+
+// CHECK: cir.func @has_attrs() attributes {baz = 5 : i64{{.*}}, floof = "flop", foo} {
+// CHECK:   cir.return
+// CHECK: }

clang/test/CIR/IR/invalid-func-attr.cir

@@ -0,0 +1,11 @@
+// RUN: cir-opt %s -verify-diagnostics
+
+module {
+  cir.func @l0() {
+    cir.return
+  }
+
+  cir.func @disallowedAttr() attributes {comdat} { // expected-error{{custom op 'cir.func' attribute 'comdat' should not be specified in the explicit attribute list}}
+    cir.return
+  }
+}