[Mlir-commits] [mlir] [mlir][mpi] Lowering Mpi To LLVM (PR #127053)

[Christian Ulmann]

================
@@ -0,0 +1,501 @@
+//===- MPIToLLVM.cpp - MPI to LLVM dialect conversion ---------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+//
+// Copyright (C) by Argonne National Laboratory
+//    See COPYRIGHT in top-level directory
+//    of MPICH source repository.
+//
+
+#include "mlir/Conversion/MPIToLLVM/MPIToLLVM.h"
+#include "mlir/Conversion/ConvertToLLVM/ToLLVMInterface.h"
+#include "mlir/Conversion/LLVMCommon/Pattern.h"
+#include "mlir/Dialect/DLTI/DLTI.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/Dialect/MPI/IR/MPI.h"
+#include "mlir/Transforms/DialectConversion.h"
+#include <memory>
+
+using namespace mlir;
+
+namespace {
+
+template <typename Op, typename... Args>
+static Op getOrDefineGlobal(ModuleOp &moduleOp, const Location loc,
+                            ConversionPatternRewriter &rewriter, StringRef name,
+                            Args &&...args) {
+  Op ret;
+  if (!(ret = moduleOp.lookupSymbol<Op>(name))) {
+    ConversionPatternRewriter::InsertionGuard guard(rewriter);
+    rewriter.setInsertionPointToStart(moduleOp.getBody());
+    ret = rewriter.template create<Op>(loc, std::forward<Args>(args)...);
+  }
+  return ret;
+}
+
+static LLVM::LLVMFuncOp getOrDefineFunction(ModuleOp &moduleOp,
+                                            const Location loc,
+                                            ConversionPatternRewriter &rewriter,
+                                            StringRef name,
+                                            LLVM::LLVMFunctionType type) {
+  return getOrDefineGlobal<LLVM::LLVMFuncOp>(
+      moduleOp, loc, rewriter, name, name, type, LLVM::Linkage::External);
+}
+
+/// When lowering the mpi dialect to functions calls certain details
+/// differ between various MPI implementations. This class will provide
+/// these in a generic way, depending on the MPI implementation that got
+/// selected by the DLTI attribute on the module.
+class MPIImplTraits {
+  ModuleOp &moduleOp;
+
+public:
+  /// Instantiate a new MPIImplTraits object according to the DLTI attribute
+  /// on the given module.
+  static std::unique_ptr<MPIImplTraits> get(ModuleOp &moduleOp);
+
+  MPIImplTraits(ModuleOp &moduleOp) : moduleOp(moduleOp) {}
+
+  ModuleOp &getModuleOp() { return moduleOp; }
+
+  /// Gets or creates MPI_COMM_WORLD as a Value.
+  virtual Value getCommWorld(const Location loc,
+                             ConversionPatternRewriter &rewriter) = 0;
+
+  /// Get the MPI_STATUS_IGNORE value (typically a pointer type).
+  virtual intptr_t getStatusIgnore() = 0;
+
+  /// get/create MPI datatype as a Value which corresponds to the given
+  /// Type
+  virtual Value getDataType(const Location loc,
+                            ConversionPatternRewriter &rewriter, Type type) = 0;
+};
+
+//===----------------------------------------------------------------------===//
+// Implementation details for MPICH ABI compatible MPI implementations
+//===----------------------------------------------------------------------===//
+
+class MPICHImplTraits : public MPIImplTraits {
+  static constexpr int MPI_FLOAT = 0x4c00040a;
+  static constexpr int MPI_DOUBLE = 0x4c00080b;
+  static constexpr int MPI_INT8_T = 0x4c000137;
+  static constexpr int MPI_INT16_T = 0x4c000238;
+  static constexpr int MPI_INT32_T = 0x4c000439;
+  static constexpr int MPI_INT64_T = 0x4c00083a;
+  static constexpr int MPI_UINT8_T = 0x4c00013b;
+  static constexpr int MPI_UINT16_T = 0x4c00023c;
+  static constexpr int MPI_UINT32_T = 0x4c00043d;
+  static constexpr int MPI_UINT64_T = 0x4c00083e;
+
+public:
+  using MPIImplTraits::MPIImplTraits;
+
+  Value getCommWorld(const Location loc,
+                     ConversionPatternRewriter &rewriter) override {
+    static const int MPI_COMM_WORLD = 0x44000000;
----------------
Dinistro wrote:

```suggestion
    static constexpr int MPI_COMM_WORLD = 0x44000000;
```

https://github.com/llvm/llvm-project/pull/127053