[MLIR] Fix circular dependency by moving StateStack to IR folder

This commit resolves a circular dependency issue between mlir/Support and mlir/IR:

- Move StateStack.h and StateStack.cpp from Support to IR folder
- Update CMakeLists.txt files to reflect the new locations
- Update Bazel BUILD file to maintain correct dependencies
- Update includes in affected files (flang, Target/LLVMIR)

The circular dependency was caused by StateStack.h depending on IR/Visitors.h
while other IR files depended on Support. Moving StateStack to IR eliminates
this cycle while maintaining proper separation of concerns.

This change improves build performance and reduces compilation issues.

Author: wang2yn84

flang/lib/Lower/Bridge.cpp

@@ -68,8 +68,8 @@
 #include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/IR/PatternMatch.h"
+#include "mlir/IR/StateStack.h"
 #include "mlir/Parser/Parser.h"
-#include "mlir/Support/StateStack.h"
 #include "mlir/Transforms/RegionUtils.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringSet.h"

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -39,7 +39,7 @@
 #include "flang/Support/OpenMP-utils.h"
 #include "mlir/Dialect/ControlFlow/IR/ControlFlowOps.h"
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
-#include "mlir/Support/StateStack.h"
+#include "mlir/IR/StateStack.h"
 #include "mlir/Transforms/RegionUtils.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Frontend/OpenMP/OMPConstants.h"

mlir/include/mlir/Support/StateStack.h renamed to mlir/include/mlir/IR/StateStack.h

@@ -12,8 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef MLIR_SUPPORT_STACKFRAME_H
-#define MLIR_SUPPORT_STACKFRAME_H
+#ifndef MLIR_IR_STACKFRAME_H
+#define MLIR_IR_STACKFRAME_H
 
 #include "mlir/IR/Visitors.h"
 #include "mlir/Support/TypeID.h"
@@ -125,4 +125,4 @@ struct isa_impl<T, ::mlir::StateStackFrame> {
 };
 } // namespace llvm
 
-#endif // MLIR_SUPPORT_STACKFRAME_H
+#endif // MLIR_IR_STACKFRAME_H

mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h

@@ -16,9 +16,9 @@
 
 #include "mlir/Dialect/LLVMIR/LLVMInterfaces.h"
 #include "mlir/IR/Operation.h"
+#include "mlir/IR/StateStack.h"
 #include "mlir/IR/SymbolTable.h"
 #include "mlir/IR/Value.h"
-#include "mlir/Support/StateStack.h"
 #include "mlir/Target/LLVMIR/Export.h"
 #include "mlir/Target/LLVMIR/LLVMTranslationInterface.h"
 #include "mlir/Target/LLVMIR/TypeToLLVM.h"

mlir/lib/IR/CMakeLists.txt

@@ -32,6 +32,7 @@ add_mlir_library(MLIRIR
   PatternMatch.cpp
   Region.cpp
   RegionKindInterface.cpp
+  StateStack.cpp
   SymbolTable.cpp
   TensorEncoding.cpp
   Types.cpp

mlir/lib/Support/StateStack.cpp renamed to mlir/lib/IR/StateStack.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "mlir/Support/StateStack.h"
+#include "mlir/IR/StateStack.h"
 
 namespace mlir {
 

mlir/lib/Support/CMakeLists.txt

@@ -11,7 +11,6 @@ add_mlir_library(MLIRSupport
   FileUtilities.cpp
   InterfaceSupport.cpp
   RawOstreamExtras.cpp
-  StateStack.cpp
   StorageUniquer.cpp
   Timing.cpp
   ToolUtilities.cpp

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

@@ -4845,11 +4845,7 @@ cc_library(
     ]),
     hdrs = glob(["include/mlir/Support/*.h"]),
     includes = ["include"],
-    deps = [
-        "//llvm:Support",
-        "//mlir:IR",
-    ],
-)
+    deps = ["//llvm:Support"],)
 
 cc_library(
     name = "Debug",