[MLIR][Test] Avoid buffer overflow for `test.verifiers`

[rikhuijzer]

Summary

Fixes buffer overflows which occurred anytime a "test.verifiers" op was used.

Fixes #61378, fixes #61379, fixes #61381.

mlir/test/IR/test-verifiers-op.mlir

+// RUN: mlir-opt %s | FileCheck %s
+
+// CHECK-LABEL: func @no_overflow_on_test_verifiers_op
+func.func @no_overflow_on_test_verifiers_op() {
+  %0 = arith.constant 1 : i32
+  "test.verifiers"(%0) ({
+    %1 = arith.constant 2 : i32
+    "test.verifiers"(%1) ({
+      %2 = arith.constant 3 : index
+    }) : (i32) -> ()
+  }) : (i32) -> ()
+  return
+}

mlir/test/lib/Dialect/Test/TestDialect.cpp

 void PrettyPrintedRegionOp::print(OpAsmPrinter &p) {
   p << ' ';
   p.printOperands(getOperands());
 
   Operation &innerOp = getRegion().front().front();
   // Assuming that region has a single non-terminator inner-op, if the inner-op
   // meets some criteria (which in this case is a simple one  based on the name
   // of inner-op), then we can print the entire region in a succinct way.
-  // Here we assume that the prototype of "test.special.op" can be trivially derived
-  // while parsing it back.
+  // Here we assume that the prototype of "test.special.op" can be trivially
+  // derived while parsing it back.
   if (innerOp.getName().getStringRef().equals("test.special.op")) {
     p << " start test.special.op end";
   } else {
     p << " (";
     p.printRegion(getRegion());
     p << ")";
   }
 

 LogicalResult TestVerifiersOp::verify() {
   if (!getRegion().hasOneBlock())
     return emitOpError("`hasOneBlock` trait hasn't been verified");
 
   Operation *definingOp = getInput().getDefiningOp();
   if (definingOp && failed(mlir::verify(definingOp)))
     return emitOpError("operand hasn't been verified");
 
-  emitRemark("success run of verifier");
+  // Avoid using `emitRemark(msg)` since that will trigger an infinite verifier
+  // loop.
+  mlir::emitRemark(getLoc(), "success run of verifier");
 
   return success();
 }
 
 LogicalResult TestVerifiersOp::verifyRegions() {
   if (!getRegion().hasOneBlock())
     return emitOpError("`hasOneBlock` trait hasn't been verified");
 
   for (Block &block : getRegion())
     for (Operation &op : block)
       if (failed(mlir::verify(&op)))
         return emitOpError("nested op hasn't been verified");
 
-  emitRemark("success run of region verifier");
+  // Avoid using `emitRemark(msg)` since that will trigger an infinite verifier
+  // loop.
+  mlir::emitRemark(getLoc(), "success run of region verifier");
 
   return success();
 }
 
 //===----------------------------------------------------------------------===//
 // Test InferIntRangeInterface
 //===----------------------------------------------------------------------===//