[flang-commits] [flang] [flang] Pass to add frame pointer attribute (PR #74598)

[Tom Eccles via flang-commits]

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@@ -0,0 +1,100 @@
+//===- FunctionAttr.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+/// \file
+/// This pass adds a `vscale_range` attribute to function definitions.
+/// The attribute is used for scalable vector operations on Arm processors
+/// and should only be run on processors that support this feature. [It is
+/// likely harmless to run it on something else, but it is also not valuable].
+//===----------------------------------------------------------------------===//
+
+#include "flang/ISO_Fortran_binding_wrapper.h"
+#include "flang/Optimizer/Builder/BoxValue.h"
+#include "flang/Optimizer/Builder/FIRBuilder.h"
+#include "flang/Optimizer/Builder/Runtime/Inquiry.h"
+#include "flang/Optimizer/Dialect/FIRDialect.h"
+#include "flang/Optimizer/Dialect/FIROps.h"
+#include "flang/Optimizer/Dialect/FIRType.h"
+#include "flang/Optimizer/Dialect/Support/FIRContext.h"
+#include "flang/Optimizer/Dialect/Support/KindMapping.h"
+#include "flang/Optimizer/Transforms/Passes.h"
+#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/IR/Matchers.h"
+#include "mlir/IR/TypeUtilities.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/DialectConversion.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+#include "mlir/Transforms/RegionUtils.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <algorithm>
+
+namespace fir {
+#define GEN_PASS_DECL_FUNCTIONATTR
+#define GEN_PASS_DEF_FUNCTIONATTR
+#include "flang/Optimizer/Transforms/Passes.h.inc"
+} // namespace fir
+
+#define DEBUG_TYPE "func-attr"
+
+namespace {
+
+class FunctionAttrPass : public fir::impl::FunctionAttrBase<FunctionAttrPass> {
+public:
+  FunctionAttrPass(const fir::FunctionAttrOptions &options) {
+    framePointerKind = options.framePointerKind;
+  }
+  FunctionAttrPass() {}
+  void runOnOperation() override;
+};
+
+} // namespace
+
+void FunctionAttrPass::runOnOperation() {
+  LLVM_DEBUG(llvm::dbgs() << "=== Begin " DEBUG_TYPE " ===\n");
+  mlir::func::FuncOp func = getOperation();
+
+  LLVM_DEBUG(llvm::dbgs() << "Func-name:" << func.getSymName() << "\n");
+
+  auto context = &getContext();
----------------
tblah wrote:

Please spell out `auto`.

In general, we only use `auto` in contexts where the type is obvious from the rest of the line. For example
```
auto attr = mlir::LLVM::FramePointerKindAttr::get(...); // type is obviously an mlir::LLVM::FramePointerKindAttr
auto func = dyn_cast<mlir::func::FuncOp>(op); // type is obviously an mlir::func::FuncOp
```

Here it is not obvious what the type is, and that makes the `&` especially hard to reason about.

https://github.com/llvm/llvm-project/pull/74598