Add support for nested symbol references.

This change allows for adding additional nested references to a SymbolRefAttr to allow for further resolving a symbol if that symbol also defines a SymbolTable. If a referenced symbol also defines a symbol table, a nested reference can be used to refer to a symbol within that table. Nested references are printed after the main reference in the following form:

  symbol-ref-attribute ::= symbol-ref-id (`::` symbol-ref-id)*

Example:

  module @reference {
    func @nested_reference()
  }

  my_reference_op @reference::@nested_reference

Given that SymbolRefAttr is now more general, the existing functionality centered around a single reference is moved to a derived class FlatSymbolRefAttr. Followup commits will add support to lookups, rauw, etc. for scoped references.

PiperOrigin-RevId: 279860501

1 files changed, 3 insertions, 3 deletions

diff --git a/mlir/test/lib/TestDialect/TestOps.td b/mlir/test/lib/TestDialect/TestOps.td
index 4071f7e232f..2972793bf02 100644
--- a/mlir/test/lib/TestDialect/TestOps.td
+++ b/mlir/test/lib/TestDialect/TestOps.td
@@ -206,7 +206,7 @@ def UpdateFloatElementsAttr : Pat<
 
 def SymbolRefOp : TEST_Op<"symbol_ref_attr"> {
   let arguments = (ins
-    Confined<SymbolRefAttr, [ReferToOp<"FuncOp">]>:$symbol
+    Confined<FlatSymbolRefAttr, [ReferToOp<"FuncOp">]>:$symbol
   );
 }
 
@@ -232,7 +232,7 @@ def SizedRegionOp : TEST_Op<"sized_region_op", []> {
 
 def ConversionCallOp : TEST_Op<"conversion_call_op",
     [CallOpInterface]> {
-  let arguments = (ins Variadic<AnyType>:$inputs, SymbolRefAttr:$callee);
+  let arguments = (ins Variadic<AnyType>:$inputs, FlatSymbolRefAttr:$callee);
   let results = (outs Variadic<AnyType>);
 
   let extraClassDeclaration = [{
@@ -241,7 +241,7 @@ def ConversionCallOp : TEST_Op<"conversion_call_op",
 
     /// Return the callee of this operation.
     CallInterfaceCallable getCallableForCallee() {
-      return getAttrOfType<SymbolRefAttr>("callee");
+      return getAttrOfType<FlatSymbolRefAttr>("callee");
     }
   }];
 }