[flang][NFC] Use tablegen to reduce MemoryAllocationOpt boilerplate

flang/include/flang/Optimizer/Transforms/Passes.h

@@ -59,13 +59,10 @@ std::unique_ptr<mlir::Pass>
 createExternalNameConversionPass(bool appendUnderscore);
 std::unique_ptr<mlir::Pass> createMemDataFlowOptPass();
 std::unique_ptr<mlir::Pass> createPromoteToAffinePass();
-std::unique_ptr<mlir::Pass> createMemoryAllocationPass();
 std::unique_ptr<mlir::Pass> createAliasTagsPass();
 std::unique_ptr<mlir::Pass>
 createAddDebugInfoPass(fir::AddDebugInfoOptions options = {});
 
-std::unique_ptr<mlir::Pass>
-createMemoryAllocationPass(bool dynOnHeap, std::size_t maxStackSize);
 std::unique_ptr<mlir::Pass> createAnnotateConstantOperandsPass();
 std::unique_ptr<mlir::Pass> createAlgebraicSimplificationPass();
 std::unique_ptr<mlir::Pass>

flang/include/flang/Optimizer/Transforms/Passes.td

@@ -247,7 +247,6 @@ def MemoryAllocationOpt : Pass<"memory-allocation-opt", "mlir::func::FuncOp"> {
            "std::size_t", /*default=*/"~static_cast<std::size_t>(0)",
            "Set maximum number of elements of an array allocated on the stack.">
   ];
-  let constructor = "::fir::createMemoryAllocationPass()";
 }
 
 def StackArrays : Pass<"stack-arrays", "mlir::ModuleOp"> {

flang/include/flang/Tools/CLOptions.inc

@@ -163,8 +163,8 @@ inline void addAVC(
 
 inline void addMemoryAllocationOpt(mlir::PassManager &pm) {
   addNestedPassConditionally<mlir::func::FuncOp>(pm, disableFirMao, [&]() {
-    return fir::createMemoryAllocationPass(
-        dynamicArrayStackToHeapAllocation, arrayStackAllocationThreshold);
+    return fir::createMemoryAllocationOpt(
+        {dynamicArrayStackToHeapAllocation, arrayStackAllocationThreshold});
   });
 }
 

flang/lib/Optimizer/Transforms/MemoryAllocation.cpp

@@ -28,17 +28,6 @@ namespace fir {
 static constexpr std::size_t unlimitedArraySize = ~static_cast<std::size_t>(0);
 
 namespace {
-struct MemoryAllocationOptions {
-  // Always move dynamic array allocations to the heap. This may result in more
-  // heap fragmentation, so may impact performance negatively.
-  bool dynamicArrayOnHeap = false;
-
-  // Number of elements in array threshold for moving to heap. In environments
-  // with limited stack size, moving large arrays to the heap can avoid running
-  // out of stack space.
-  std::size_t maxStackArraySize = unlimitedArraySize;
-};
-
 class ReturnAnalysis {
 public:
   MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(ReturnAnalysis)
@@ -68,8 +57,9 @@ class ReturnAnalysis {
 
 /// Return `true` if this allocation is to remain on the stack (`fir.alloca`).
 /// Otherwise the allocation should be moved to the heap (`fir.allocmem`).
-static inline bool keepStackAllocation(fir::AllocaOp alloca, mlir::Block *entry,
-                                       const MemoryAllocationOptions &options) {
+static inline bool
+keepStackAllocation(fir::AllocaOp alloca, mlir::Block *entry,
+                    const fir::MemoryAllocationOptOptions &options) {
   // Limitation: only arrays allocated on the stack in the entry block are
   // considered for now.
   // TODO: Generalize the algorithm and placement of the freemem nodes.
@@ -168,6 +158,9 @@ class MemoryAllocationOpt
     options = {dynOnHeap, maxStackSize};
   }
 
+  MemoryAllocationOpt(const fir::MemoryAllocationOptOptions &options)
+      : options{options} {}
+
   /// Override `options` if command-line options have been set.
   inline void useCommandLineOptions() {
     if (dynamicArrayOnHeap)
@@ -211,15 +204,6 @@ class MemoryAllocationOpt
   }
 
 private:
-  MemoryAllocationOptions options;
+  fir::MemoryAllocationOptOptions options;
 };
 } // namespace
-
-std::unique_ptr<mlir::Pass> fir::createMemoryAllocationPass() {
-  return std::make_unique<MemoryAllocationOpt>();
-}
-
-std::unique_ptr<mlir::Pass>
-fir::createMemoryAllocationPass(bool dynOnHeap, std::size_t maxStackSize) {
-  return std::make_unique<MemoryAllocationOpt>(dynOnHeap, maxStackSize);
-}