Revert "[FIRRTL] Don't enforce owning module for local ref in LowerCl…

…asses. (llvm#6811)"

This reverts commit c12c68d.

This was a quick workaround, but a better solution is being developed.

lib/Dialect/FIRRTL/Transforms/LowerClasses.cpp

@@ -269,17 +269,8 @@ LogicalResult LowerClassesPass::processPaths(
         if (node->getModule() == owningModule)
           break;
         // If there are no more parents, then the path op lives in a different
-        // hierarchy than the HW object it references, which is an error if the
-        // reference is hierarchical. We allow local targets in this case
-        // because we intentionally extract some things out of the owning module
-        // for legacy reasons, and expect to target them with local targets.
-        // Once that is fixed, we can restore the invariant that the path op
-        // lives in the same hierarchy as the HW object it references.
+        // hierarchy than the HW object it references, which is an error.
         if (node->noUses()) {
-          // Local target temporary special case.
-          if (!hierPathOp)
-            break;
-
           op->emitError() << "unable to resolve path relative to owning module "
                           << owningModule.getModuleNameAttr();
           error = true;

test/Dialect/FIRRTL/lower-classes.mlir

@@ -154,18 +154,13 @@ firrtl.circuit "Component" {
 
 // CHECK-LABEL: firrtl.circuit "PathModule"
 firrtl.circuit "PathModule" {
-  // CHECK: hw.hierpath private [[LOCAL_PATH_NOT_OWNED:@.+]] [@NotOwned::@wire]
   // CHECK: hw.hierpath private [[PORT_PATH:@.+]] [@PathModule::[[PORT_SYM:@.+]]]
   // CHECK: hw.hierpath private [[WIRE_PATH:@.+]] [@PathModule::[[WIRE_SYM:@.+]]]
   // CHECK: hw.hierpath private [[VECTOR_PATH:@.+]] [@PathModule::[[VECTOR_SYM:@.+]]]
   // CHECK: hw.hierpath private [[INST_PATH:@.+]] [@PathModule::@child]
   // CHECK: hw.hierpath private [[MODULE_PATH:@.+]] [@Child]
   // CHECK: hw.hierpath private [[NONLOCAL_PATH:@.+]] [@PathModule::@child, @Child::[[NONLOCAL_SYM:@.+]]]
 
-  firrtl.module @NotOwned() {
-    %wire = firrtl.wire sym @wire {annotations = [{class = "circt.tracker", id = distinct[6]<>}]} : !firrtl.uint<1>
-  }
-
   // CHECK: firrtl.module @PathModule(in %in: !firrtl.uint<1> sym [[PORT_SYM]]) {
   firrtl.module @PathModule(in %in : !firrtl.uint<1> [{class = "circt.tracker", id = distinct[0]<>}]) {
     // CHECK: %wire = firrtl.wire sym [[WIRE_SYM]] : !firrtl.uint<8>
@@ -216,9 +211,6 @@ firrtl.circuit "PathModule" {
 
     // CHECK: om.path_create reference %basepath [[MODULE_PATH]]
     %module_path = firrtl.path reference distinct[5]<>
-
-    // CHECK: om.path_create reference %basepath [[LOCAL_PATH_NOT_OWNED]]
-    %local_path_not_owned = firrtl.path reference distinct[6]<>
   }
   firrtl.module @ListCreate(in %propIn: !firrtl.integer, out %propOut: !firrtl.list<integer>) attributes {convention = #firrtl<convention scalarized>} {
     %0 = firrtl.integer 123