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, 2 insertions, 1 deletions

diff --git a/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp b/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
index d70d51feee7..bfd094d6203 100644
--- a/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
+++ b/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
@@ -533,7 +533,8 @@ unsigned LaunchFuncOp::getNumKernelOperands() {
 }
 
 StringRef LaunchFuncOp::getKernelModuleName() {
-  return getAttrOfType<SymbolRefAttr>(getKernelModuleAttrName()).getValue();
+  return getAttrOfType<SymbolRefAttr>(getKernelModuleAttrName())
+      .getRootReference();
 }
 
 Value *LaunchFuncOp::getKernelOperand(unsigned i) {