[mlir][acc] Add OpenACCSupport for extensible dialect handling #164510

razvanlupusoru · 2025-10-21T22:35:17Z

The OpenACC dialect must coexist with source language dialects (FIR, CIR, etc.) to enable offloading. While type interfaces (PointerLikeType and MappableType) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone.

This commit introduces the OpenACCSupport analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's AliasAnalysis and is never invalidated, persisting throughout the pass pipeline.

The initial API, getVariableName(Value) -> string, retrieves variable names from MLIR values by:

Checking for acc.var_name attributes
Extracting names from ACC data clause operations (e.g., acc.copyin)
Walking through ViewLikeOpInterface operations to find the source

This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names.

Usage: Passes call getAnalysis<OpenACCSupport>() to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling setImplementation() before the consumer pass runs.

The OpenACC dialect must coexist with source language dialects (FIR, LLVM, etc.) to enable offloading. While type interfaces (`PointerLikeType` and `MappableType`) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone. This commit introduces the `OpenACCSupport` analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's `AliasAnalysis` and is never invalidated, persisting throughout the pass pipeline. The initial API, `getVariableName(Value) -> string`, retrieves variable names from MLIR values by: - Checking for `acc.var_name` attributes - Extracting names from ACC data clause operations (e.g., `acc.copyin`) - Walking through `ViewLikeOpInterface` operations to find the source This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names. Usage: Passes call `getAnalysis<OpenACCSupport>()` to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling `setImplementation()` before the consumer pass runs.

llvmbot · 2025-10-21T22:36:02Z

@llvm/pr-subscribers-openacc

@llvm/pr-subscribers-mlir-openacc

Author: Razvan Lupusoru (razvanlupusoru)

Changes

The OpenACC dialect must coexist with source language dialects (FIR, LLVM, etc.) to enable offloading. While type interfaces (PointerLikeType and MappableType) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone.

This commit introduces the OpenACCSupport analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's AliasAnalysis and is never invalidated, persisting throughout the pass pipeline.

The initial API, getVariableName(Value) -> string, retrieves variable names from MLIR values by:

Checking for acc.var_name attributes
Extracting names from ACC data clause operations (e.g., acc.copyin)
Walking through ViewLikeOpInterface operations to find the source

This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names.

Usage: Passes call getAnalysis<OpenACCSupport>() to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling setImplementation() before the consumer pass runs.

Full diff: https://github.com/llvm/llvm-project/pull/164510.diff

11 Files Affected:

(added) mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h (+134)
(modified) mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h (+5)
(added) mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt (+13)
(added) mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp (+26)
(modified) mlir/lib/Dialect/OpenACC/CMakeLists.txt (+1)
(modified) mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp (+28)
(added) mlir/test/Dialect/OpenACC/support-analysis-varname.mlir (+88)
(modified) mlir/test/lib/Dialect/OpenACC/CMakeLists.txt (+2)
(modified) mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp (+2)
(added) mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp (+73)
(modified) mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp (+75)

diff --git a/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h b/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h
new file mode 100644
index 0000000000000..c1723cb033d42
--- /dev/null
+++ b/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h
@@ -0,0 +1,134 @@
+//===- OpenACCSupport.h - OpenACC Support Interface -------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the OpenACCSupport analysis interface, which provides
+// extensible support for OpenACC passes. Custom implementations
+// can be registered to provide pipeline and dialect-specific information
+// that cannot be adequately expressed through type or operation interfaces
+// alone.
+//
+// Usage Pattern:
+// ==============
+//
+// A pass that needs this functionality should call getAnalysis<OpenACCSupport>(),
+// which will provide either:
+// - A cached version if previously initialized, OR
+// - A default implementation if not previously initialized
+//
+// This analysis is never invalidated (isInvalidated returns false), so it only
+// needs to be initialized once and will persist throughout the pass pipeline.
+//
+// Registering a Custom Implementation:
+// =====================================
+//
+// If a custom implementation is needed, create a pass that runs BEFORE the pass
+// that needs the analysis. In this setup pass, use getAnalysis<OpenACCSupport>()
+// followed by setImplementation() to register your custom implementation. The
+// custom implementation will need to provide implementation for all methods
+// defined in the `OpenACCSupportTraits::Concept` class.
+//
+// Example:
+//   void MySetupPass::runOnOperation() {
+//     OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+//     support.setImplementation(MyCustomImpl());
+//   }
+//
+//   void MyAnalysisConsumerPass::runOnOperation() {
+//     OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+//     std::string name = support.getVariableName(someValue);
+//     // ... use the analysis results
+//   }
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
+#define MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
+
+#include "mlir/IR/Value.h"
+#include "mlir/Pass/AnalysisManager.h"
+#include <memory>
+#include <string>
+
+namespace mlir {
+namespace acc {
+
+namespace detail {
+/// This class contains internal trait classes used by OpenACCSupport.
+/// It follows the Concept-Model pattern used throughout MLIR (e.g., in
+/// AliasAnalysis and interface definitions).
+struct OpenACCSupportTraits {
+  class Concept {
+  public:
+    virtual ~Concept() = default;
+
+    /// Get the variable name for a given MLIR value.
+    virtual std::string getVariableName(Value v) = 0;
+  };
+
+  /// This class wraps a concrete OpenACCSupport implementation and forwards
+  /// interface calls to it. This provides type erasure, allowing different
+  /// implementation types to be used interchangeably without inheritance.
+  template <typename ImplT>
+  class Model final : public Concept {
+  public:
+    explicit Model(ImplT &&impl) : impl(std::forward<ImplT>(impl)) {}
+    ~Model() override = default;
+
+    std::string getVariableName(Value v) final {
+      return impl.getVariableName(v);
+    }
+
+  private:
+    ImplT impl;
+  };
+};
+} // namespace detail
+
+//===----------------------------------------------------------------------===//
+// OpenACCSupport
+//===----------------------------------------------------------------------===//
+
+class OpenACCSupport {
+  using Concept = detail::OpenACCSupportTraits::Concept;
+  template <typename ImplT>
+  using Model = detail::OpenACCSupportTraits::Model<ImplT>;
+
+public:
+  OpenACCSupport() = default;
+  OpenACCSupport(Operation *op) {}
+
+  /// Register a custom OpenACCSupport implementation. Only one implementation
+  /// can be registered at a time; calling this replaces any existing
+  /// implementation.
+  template <typename AnalysisT>
+  void setImplementation(AnalysisT &&analysis) {
+    impl =
+        std::make_unique<Model<AnalysisT>>(std::forward<AnalysisT>(analysis));
+  }
+
+  /// Get the variable name for a given value.
+  ///
+  /// \param v The MLIR value to get the variable name for.
+  /// \return The variable name, or an empty string if unavailable.
+  std::string getVariableName(Value v);
+
+  /// Signal that this analysis should always be preserved so that
+  /// underlying implementation registration is not lost.
+  bool isInvalidated(const AnalysisManager::PreservedAnalyses &pa) {
+    return false;
+  }
+
+private:
+  /// The registered custom implementation (if any).
+  std::unique_ptr<Concept> impl;
+};
+
+} // namespace acc
+} // namespace mlir
+
+#endif // MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
diff --git a/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h b/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
index 378f4348f2cf1..0ee88c6f47b67 100644
--- a/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
+++ b/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
@@ -38,6 +38,11 @@ std::optional<ClauseDefaultValue> getDefaultAttr(mlir::Operation *op);
 /// Get the type category of an OpenACC variable.
 mlir::acc::VariableTypeCategory getTypeCategory(mlir::Value var);
 
+/// Attempts to extract the variable name from a value by walking through
+/// view-like operations until an `acc.var_name` attribute is found. Returns
+/// empty string if no name is found.
+std::string getVariableName(mlir::Value v);
+
 } // namespace acc
 } // namespace mlir
 
diff --git a/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt b/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt
new file mode 100644
index 0000000000000..f305068e1b3bc
--- /dev/null
+++ b/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_mlir_dialect_library(MLIROpenACCAnalysis
+  OpenACCSupport.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/OpenACC
+
+  LINK_LIBS PUBLIC
+  MLIRIR
+  MLIROpenACCDialect
+  MLIROpenACCUtils
+  MLIRSupport
+)
+
diff --git a/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp b/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp
new file mode 100644
index 0000000000000..f6b4534794eaf
--- /dev/null
+++ b/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp
@@ -0,0 +1,26 @@
+//===- OpenACCSupport.cpp - OpenACCSupport Implementation -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the OpenACCSupport analysis interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h"
+#include "mlir/Dialect/OpenACC/OpenACCUtils.h"
+
+namespace mlir {
+namespace acc {
+
+std::string OpenACCSupport::getVariableName(Value v) {
+  if (impl)
+    return impl->getVariableName(v);
+  return acc::getVariableName(v);
+}
+
+} // namespace acc
+} // namespace mlir
diff --git a/mlir/lib/Dialect/OpenACC/CMakeLists.txt b/mlir/lib/Dialect/OpenACC/CMakeLists.txt
index 7117520599fa6..e8a916e824d71 100644
--- a/mlir/lib/Dialect/OpenACC/CMakeLists.txt
+++ b/mlir/lib/Dialect/OpenACC/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory(Analysis)
 add_subdirectory(IR)
 add_subdirectory(Utils)
 add_subdirectory(Transforms)
diff --git a/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp b/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
index 12233254f3fb4..89adda82646e6 100644
--- a/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
+++ b/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
@@ -9,6 +9,7 @@
 #include "mlir/Dialect/OpenACC/OpenACCUtils.h"
 
 #include "mlir/Dialect/OpenACC/OpenACC.h"
+#include "mlir/Interfaces/ViewLikeInterface.h"
 #include "llvm/ADT/TypeSwitch.h"
 
 mlir::Operation *mlir::acc::getEnclosingComputeOp(mlir::Region &region) {
@@ -78,3 +79,30 @@ mlir::acc::VariableTypeCategory mlir::acc::getTypeCategory(mlir::Value var) {
         pointerLikeTy.getElementType());
   return typeCategory;
 }
+
+std::string mlir::acc::getVariableName(mlir::Value v) {
+  Value current = v;
+
+  // Walk through view operations until a name is found or can't go further
+  while (Operation *definingOp = current.getDefiningOp()) {
+    // Check for `acc.var_name` attribute
+    if (auto varNameAttr =
+            definingOp->getAttrOfType<VarNameAttr>(getVarNameAttrName()))
+      return varNameAttr.getName().str();
+
+    // If it is a data entry operation, get name via getVarName
+    if (isa<ACC_DATA_ENTRY_OPS>(definingOp))
+      if (auto name = acc::getVarName(definingOp))
+        return name->str();
+
+    // If it's a view operation, continue to the source
+    if (auto viewOp = dyn_cast<ViewLikeOpInterface>(definingOp)) {
+      current = viewOp.getViewSource();
+      continue;
+    }
+
+    break;
+  }
+
+  return "";
+}
diff --git a/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir b/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir
new file mode 100644
index 0000000000000..af52befb156e4
--- /dev/null
+++ b/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir
@@ -0,0 +1,88 @@
+// RUN: mlir-opt %s -split-input-file -test-acc-support | FileCheck %s
+
+// Test with direct variable names
+func.func @test_direct_var_name() {
+  // Create a memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"my_variable">} : memref<10xi32>
+
+  %1 = memref.cast %0 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName="my_variable"
+
+  return
+}
+
+// -----
+
+// Test through memref.cast
+func.func @test_through_cast() {
+  // Create a 5x2 memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"casted_variable">} : memref<5x2xi32>
+
+  // Cast to dynamic dimensions
+  %1 = memref.cast %0 : memref<5x2xi32> to memref<?x?xi32>
+
+  // Mark with test attribute - should find name through cast
+  %2 = memref.cast %1 {test.var_name} : memref<?x?xi32> to memref<5x2xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<?x?xi32> to memref<5x2xi32>
+  // CHECK-NEXT: getVariableName="casted_variable"
+
+  return
+}
+
+// -----
+
+// Test with no variable name
+func.func @test_no_var_name() {
+  // Create a memref without acc.var_name attribute
+  %0 = memref.alloca() : memref<10xi32>
+
+  // Mark with test attribute - should find empty string
+  %1 = memref.cast %0 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName=""
+
+  return
+}
+
+// -----
+
+// Test through multiple casts
+func.func @test_multiple_casts() {
+  // Create a memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"multi_cast">} : memref<10xi32>
+
+  // Multiple casts
+  %1 = memref.cast %0 : memref<10xi32> to memref<?xi32>
+  %2 = memref.cast %1 : memref<?xi32> to memref<10xi32>
+
+  // Mark with test attribute - should find name through multiple casts
+  %3 = memref.cast %2 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName="multi_cast"
+
+  return
+}
+
+// -----
+
+// Test with acc.copyin operation
+func.func @test_copyin_name() {
+  // Create a memref
+  %0 = memref.alloca() : memref<10xf32>
+
+  // Create an acc.copyin operation with a name
+  %1 = acc.copyin varPtr(%0 : memref<10xf32>) -> memref<10xf32> {name = "input_data"}
+
+  // Mark with test attribute - should find name from copyin operation
+  %2 = memref.cast %1 {test.var_name} : memref<10xf32> to memref<?xf32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xf32> to memref<?xf32>
+  // CHECK-NEXT: getVariableName="input_data"
+
+  return
+}
diff --git a/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt b/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
index 1e593389ec683..a54b642d4db42 100644
--- a/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
+++ b/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
@@ -2,6 +2,7 @@ add_mlir_library(MLIROpenACCTestPasses
   TestOpenACC.cpp
   TestPointerLikeTypeInterface.cpp
   TestRecipePopulate.cpp
+  TestOpenACCSupport.cpp
   
   EXCLUDE_FROM_LIBMLIR
 )
@@ -11,6 +12,7 @@ mlir_target_link_libraries(MLIROpenACCTestPasses PUBLIC
   MLIRFuncDialect
   MLIRMemRefDialect
   MLIROpenACCDialect
+  MLIROpenACCAnalysis
   MLIRPass
   MLIRSupport
 )
diff --git a/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp b/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
index bea21b9827f7e..e59d77777ee40 100644
--- a/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
+++ b/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
@@ -16,11 +16,13 @@ namespace test {
 // Forward declarations of individual test pass registration functions
 void registerTestPointerLikeTypeInterfacePass();
 void registerTestRecipePopulatePass();
+void registerTestOpenACCSupportPass();
 
 // Unified registration function for all OpenACC tests
 void registerTestOpenACC() {
   registerTestPointerLikeTypeInterfacePass();
   registerTestRecipePopulatePass();
+  registerTestOpenACCSupportPass();
 }
 
 } // namespace test
diff --git a/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp b/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp
new file mode 100644
index 0000000000000..8bf984bdc2632
--- /dev/null
+++ b/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp
@@ -0,0 +1,73 @@
+//===- TestOpenACCSupport.cpp - Test OpenACCSupport Analysis -------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains test passes for testing the OpenACCSupport analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/MemRef/IR/MemRef.h"
+#include "mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h"
+#include "mlir/Dialect/OpenACC/OpenACC.h"
+#include "mlir/Pass/Pass.h"
+
+using namespace mlir;
+using namespace mlir::acc;
+
+namespace {
+
+struct TestOpenACCSupportPass
+    : public PassWrapper<TestOpenACCSupportPass, OperationPass<func::FuncOp>> {
+  MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestOpenACCSupportPass)
+
+  StringRef getArgument() const override { return "test-acc-support"; }
+
+  StringRef getDescription() const override {
+    return "Test OpenACCSupport analysis";
+  }
+
+  void runOnOperation() override;
+
+  void getDependentDialects(DialectRegistry &registry) const override {
+    registry.insert<acc::OpenACCDialect>();
+    registry.insert<memref::MemRefDialect>();
+  }
+};
+
+void TestOpenACCSupportPass::runOnOperation() {
+  auto func = getOperation();
+
+  // Get the OpenACCSupport analysis
+  OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+
+  // Walk through operations looking for test attributes
+  func.walk([&](Operation *op) {
+    // Check for test.var_name attribute. This is the marker used to identify
+    // the operations that need to be tested for getVariableName.
+    if (op->hasAttr("test.var_name")) {
+      // For each result of this operation, try to get the variable name
+      for (auto result : op->getResults()) {
+        std::string foundName = support.getVariableName(result);
+        llvm::outs() << "op=" << *op << "\n\tgetVariableName=\"" << foundName
+                     << "\"\n";
+      }
+    }
+  });
+}
+
+} // namespace
+
+namespace mlir {
+namespace test {
+
+void registerTestOpenACCSupportPass() {
+  PassRegistration<TestOpenACCSupportPass>();
+}
+
+} // namespace test
+} // namespace mlir
diff --git a/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp b/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
index ab817b640edb3..3fbbcc90a67c9 100644
--- a/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
+++ b/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
@@ -410,3 +410,78 @@ TEST_F(OpenACCUtilsTest, getTypeCategoryArray) {
   VariableTypeCategory category = getTypeCategory(varPtr);
   EXPECT_EQ(category, VariableTypeCategory::array);
 }
+
+//===----------------------------------------------------------------------===//
+// getVariableName Tests
+//===----------------------------------------------------------------------===//
+
+TEST_F(OpenACCUtilsTest, getVariableNameDirect) {
+  // Create a memref with acc.var_name attribute
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  // Set the acc.var_name attribute
+  auto varNameAttr = VarNameAttr::get(&context, "my_variable");
+  allocOp.get()->setAttr(getVarNameAttrName(), varNameAttr);
+
+  Value varPtr = allocOp->getResult();
+
+  // Test that getVariableName returns the variable name
+  std::string varName = getVariableName(varPtr);
+  EXPECT_EQ(varName, "my_variable");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameThroughCast) {
+  // Create a 5x2 memref with acc.var_name attribute
+  auto memrefTy = MemRefType::get({5, 2}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  // Set the acc.var_name attribute on the alloca
+  auto varNameAttr = VarNameAttr::get(&context, "casted_variable");
+  allocOp.get()->setAttr(getVarNameAttrName(), varNameAttr);
+
+  Value allocResult = allocOp->getResult();
+
+  // Create a memref.cast operation to a flattened 10-element array
+  auto castedMemrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::CastOp> castOp =
+      memref::CastOp::create(b, loc, castedMemrefTy, allocResult);
+
+  Value castedPtr = castOp->getResult();
+
+  // Test that getVariableName walks through the cast to find the variable name
+  std::string varName = getVariableName(castedPtr);
+  EXPECT_EQ(varName, "casted_variable");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameNotFound) {
+  // Create a memref without acc.var_name attribute
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  Value varPtr = allocOp->getResult();
+
+  // Test that getVariableName returns empty string when no name is found
+  std::string varName = getVariableName(varPtr);
+  EXPECT_EQ(varName, "");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameFromCopyin) {
+  // Create a memref
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  Value varPtr = allocOp->getResult();
+  StringRef name = "data_array";
+  OwningOpRef<CopyinOp> copyinOp =
+      CopyinOp::create(b, loc, varPtr, /*structured=*/true, /*implicit=*/true,
+                       /*name=*/name);
+
+  // Test that getVariableName extracts the name from the copyin operation
+  std::string varName = getVariableName(copyinOp->getAccVar());
+  EXPECT_EQ(varName, name);
+}

llvmbot · 2025-10-21T22:36:03Z

@llvm/pr-subscribers-mlir

Author: Razvan Lupusoru (razvanlupusoru)

Changes

The OpenACC dialect must coexist with source language dialects (FIR, LLVM, etc.) to enable offloading. While type interfaces (PointerLikeType and MappableType) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone.

This commit introduces the OpenACCSupport analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's AliasAnalysis and is never invalidated, persisting throughout the pass pipeline.

The initial API, getVariableName(Value) -> string, retrieves variable names from MLIR values by:

Checking for acc.var_name attributes
Extracting names from ACC data clause operations (e.g., acc.copyin)
Walking through ViewLikeOpInterface operations to find the source

This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names.

Usage: Passes call getAnalysis<OpenACCSupport>() to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling setImplementation() before the consumer pass runs.

Full diff: https://github.com/llvm/llvm-project/pull/164510.diff

11 Files Affected:

(added) mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h (+134)
(modified) mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h (+5)
(added) mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt (+13)
(added) mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp (+26)
(modified) mlir/lib/Dialect/OpenACC/CMakeLists.txt (+1)
(modified) mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp (+28)
(added) mlir/test/Dialect/OpenACC/support-analysis-varname.mlir (+88)
(modified) mlir/test/lib/Dialect/OpenACC/CMakeLists.txt (+2)
(modified) mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp (+2)
(added) mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp (+73)
(modified) mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp (+75)

diff --git a/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h b/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h
new file mode 100644
index 0000000000000..c1723cb033d42
--- /dev/null
+++ b/mlir/include/mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h
@@ -0,0 +1,134 @@
+//===- OpenACCSupport.h - OpenACC Support Interface -------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the OpenACCSupport analysis interface, which provides
+// extensible support for OpenACC passes. Custom implementations
+// can be registered to provide pipeline and dialect-specific information
+// that cannot be adequately expressed through type or operation interfaces
+// alone.
+//
+// Usage Pattern:
+// ==============
+//
+// A pass that needs this functionality should call getAnalysis<OpenACCSupport>(),
+// which will provide either:
+// - A cached version if previously initialized, OR
+// - A default implementation if not previously initialized
+//
+// This analysis is never invalidated (isInvalidated returns false), so it only
+// needs to be initialized once and will persist throughout the pass pipeline.
+//
+// Registering a Custom Implementation:
+// =====================================
+//
+// If a custom implementation is needed, create a pass that runs BEFORE the pass
+// that needs the analysis. In this setup pass, use getAnalysis<OpenACCSupport>()
+// followed by setImplementation() to register your custom implementation. The
+// custom implementation will need to provide implementation for all methods
+// defined in the `OpenACCSupportTraits::Concept` class.
+//
+// Example:
+//   void MySetupPass::runOnOperation() {
+//     OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+//     support.setImplementation(MyCustomImpl());
+//   }
+//
+//   void MyAnalysisConsumerPass::runOnOperation() {
+//     OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+//     std::string name = support.getVariableName(someValue);
+//     // ... use the analysis results
+//   }
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
+#define MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
+
+#include "mlir/IR/Value.h"
+#include "mlir/Pass/AnalysisManager.h"
+#include <memory>
+#include <string>
+
+namespace mlir {
+namespace acc {
+
+namespace detail {
+/// This class contains internal trait classes used by OpenACCSupport.
+/// It follows the Concept-Model pattern used throughout MLIR (e.g., in
+/// AliasAnalysis and interface definitions).
+struct OpenACCSupportTraits {
+  class Concept {
+  public:
+    virtual ~Concept() = default;
+
+    /// Get the variable name for a given MLIR value.
+    virtual std::string getVariableName(Value v) = 0;
+  };
+
+  /// This class wraps a concrete OpenACCSupport implementation and forwards
+  /// interface calls to it. This provides type erasure, allowing different
+  /// implementation types to be used interchangeably without inheritance.
+  template <typename ImplT>
+  class Model final : public Concept {
+  public:
+    explicit Model(ImplT &&impl) : impl(std::forward<ImplT>(impl)) {}
+    ~Model() override = default;
+
+    std::string getVariableName(Value v) final {
+      return impl.getVariableName(v);
+    }
+
+  private:
+    ImplT impl;
+  };
+};
+} // namespace detail
+
+//===----------------------------------------------------------------------===//
+// OpenACCSupport
+//===----------------------------------------------------------------------===//
+
+class OpenACCSupport {
+  using Concept = detail::OpenACCSupportTraits::Concept;
+  template <typename ImplT>
+  using Model = detail::OpenACCSupportTraits::Model<ImplT>;
+
+public:
+  OpenACCSupport() = default;
+  OpenACCSupport(Operation *op) {}
+
+  /// Register a custom OpenACCSupport implementation. Only one implementation
+  /// can be registered at a time; calling this replaces any existing
+  /// implementation.
+  template <typename AnalysisT>
+  void setImplementation(AnalysisT &&analysis) {
+    impl =
+        std::make_unique<Model<AnalysisT>>(std::forward<AnalysisT>(analysis));
+  }
+
+  /// Get the variable name for a given value.
+  ///
+  /// \param v The MLIR value to get the variable name for.
+  /// \return The variable name, or an empty string if unavailable.
+  std::string getVariableName(Value v);
+
+  /// Signal that this analysis should always be preserved so that
+  /// underlying implementation registration is not lost.
+  bool isInvalidated(const AnalysisManager::PreservedAnalyses &pa) {
+    return false;
+  }
+
+private:
+  /// The registered custom implementation (if any).
+  std::unique_ptr<Concept> impl;
+};
+
+} // namespace acc
+} // namespace mlir
+
+#endif // MLIR_DIALECT_OPENACC_ANALYSIS_OPENACCSUPPORT_H
diff --git a/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h b/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
index 378f4348f2cf1..0ee88c6f47b67 100644
--- a/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
+++ b/mlir/include/mlir/Dialect/OpenACC/OpenACCUtils.h
@@ -38,6 +38,11 @@ std::optional<ClauseDefaultValue> getDefaultAttr(mlir::Operation *op);
 /// Get the type category of an OpenACC variable.
 mlir::acc::VariableTypeCategory getTypeCategory(mlir::Value var);
 
+/// Attempts to extract the variable name from a value by walking through
+/// view-like operations until an `acc.var_name` attribute is found. Returns
+/// empty string if no name is found.
+std::string getVariableName(mlir::Value v);
+
 } // namespace acc
 } // namespace mlir
 
diff --git a/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt b/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt
new file mode 100644
index 0000000000000..f305068e1b3bc
--- /dev/null
+++ b/mlir/lib/Dialect/OpenACC/Analysis/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_mlir_dialect_library(MLIROpenACCAnalysis
+  OpenACCSupport.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/OpenACC
+
+  LINK_LIBS PUBLIC
+  MLIRIR
+  MLIROpenACCDialect
+  MLIROpenACCUtils
+  MLIRSupport
+)
+
diff --git a/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp b/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp
new file mode 100644
index 0000000000000..f6b4534794eaf
--- /dev/null
+++ b/mlir/lib/Dialect/OpenACC/Analysis/OpenACCSupport.cpp
@@ -0,0 +1,26 @@
+//===- OpenACCSupport.cpp - OpenACCSupport Implementation -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the OpenACCSupport analysis interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h"
+#include "mlir/Dialect/OpenACC/OpenACCUtils.h"
+
+namespace mlir {
+namespace acc {
+
+std::string OpenACCSupport::getVariableName(Value v) {
+  if (impl)
+    return impl->getVariableName(v);
+  return acc::getVariableName(v);
+}
+
+} // namespace acc
+} // namespace mlir
diff --git a/mlir/lib/Dialect/OpenACC/CMakeLists.txt b/mlir/lib/Dialect/OpenACC/CMakeLists.txt
index 7117520599fa6..e8a916e824d71 100644
--- a/mlir/lib/Dialect/OpenACC/CMakeLists.txt
+++ b/mlir/lib/Dialect/OpenACC/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory(Analysis)
 add_subdirectory(IR)
 add_subdirectory(Utils)
 add_subdirectory(Transforms)
diff --git a/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp b/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
index 12233254f3fb4..89adda82646e6 100644
--- a/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
+++ b/mlir/lib/Dialect/OpenACC/Utils/OpenACCUtils.cpp
@@ -9,6 +9,7 @@
 #include "mlir/Dialect/OpenACC/OpenACCUtils.h"
 
 #include "mlir/Dialect/OpenACC/OpenACC.h"
+#include "mlir/Interfaces/ViewLikeInterface.h"
 #include "llvm/ADT/TypeSwitch.h"
 
 mlir::Operation *mlir::acc::getEnclosingComputeOp(mlir::Region &region) {
@@ -78,3 +79,30 @@ mlir::acc::VariableTypeCategory mlir::acc::getTypeCategory(mlir::Value var) {
         pointerLikeTy.getElementType());
   return typeCategory;
 }
+
+std::string mlir::acc::getVariableName(mlir::Value v) {
+  Value current = v;
+
+  // Walk through view operations until a name is found or can't go further
+  while (Operation *definingOp = current.getDefiningOp()) {
+    // Check for `acc.var_name` attribute
+    if (auto varNameAttr =
+            definingOp->getAttrOfType<VarNameAttr>(getVarNameAttrName()))
+      return varNameAttr.getName().str();
+
+    // If it is a data entry operation, get name via getVarName
+    if (isa<ACC_DATA_ENTRY_OPS>(definingOp))
+      if (auto name = acc::getVarName(definingOp))
+        return name->str();
+
+    // If it's a view operation, continue to the source
+    if (auto viewOp = dyn_cast<ViewLikeOpInterface>(definingOp)) {
+      current = viewOp.getViewSource();
+      continue;
+    }
+
+    break;
+  }
+
+  return "";
+}
diff --git a/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir b/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir
new file mode 100644
index 0000000000000..af52befb156e4
--- /dev/null
+++ b/mlir/test/Dialect/OpenACC/support-analysis-varname.mlir
@@ -0,0 +1,88 @@
+// RUN: mlir-opt %s -split-input-file -test-acc-support | FileCheck %s
+
+// Test with direct variable names
+func.func @test_direct_var_name() {
+  // Create a memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"my_variable">} : memref<10xi32>
+
+  %1 = memref.cast %0 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName="my_variable"
+
+  return
+}
+
+// -----
+
+// Test through memref.cast
+func.func @test_through_cast() {
+  // Create a 5x2 memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"casted_variable">} : memref<5x2xi32>
+
+  // Cast to dynamic dimensions
+  %1 = memref.cast %0 : memref<5x2xi32> to memref<?x?xi32>
+
+  // Mark with test attribute - should find name through cast
+  %2 = memref.cast %1 {test.var_name} : memref<?x?xi32> to memref<5x2xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<?x?xi32> to memref<5x2xi32>
+  // CHECK-NEXT: getVariableName="casted_variable"
+
+  return
+}
+
+// -----
+
+// Test with no variable name
+func.func @test_no_var_name() {
+  // Create a memref without acc.var_name attribute
+  %0 = memref.alloca() : memref<10xi32>
+
+  // Mark with test attribute - should find empty string
+  %1 = memref.cast %0 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName=""
+
+  return
+}
+
+// -----
+
+// Test through multiple casts
+func.func @test_multiple_casts() {
+  // Create a memref with acc.var_name attribute
+  %0 = memref.alloca() {acc.var_name = #acc.var_name<"multi_cast">} : memref<10xi32>
+
+  // Multiple casts
+  %1 = memref.cast %0 : memref<10xi32> to memref<?xi32>
+  %2 = memref.cast %1 : memref<?xi32> to memref<10xi32>
+
+  // Mark with test attribute - should find name through multiple casts
+  %3 = memref.cast %2 {test.var_name} : memref<10xi32> to memref<10xi32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xi32> to memref<10xi32>
+  // CHECK-NEXT: getVariableName="multi_cast"
+
+  return
+}
+
+// -----
+
+// Test with acc.copyin operation
+func.func @test_copyin_name() {
+  // Create a memref
+  %0 = memref.alloca() : memref<10xf32>
+
+  // Create an acc.copyin operation with a name
+  %1 = acc.copyin varPtr(%0 : memref<10xf32>) -> memref<10xf32> {name = "input_data"}
+
+  // Mark with test attribute - should find name from copyin operation
+  %2 = memref.cast %1 {test.var_name} : memref<10xf32> to memref<?xf32>
+
+  // CHECK: op=%{{.*}} = memref.cast %{{.*}} {test.var_name} : memref<10xf32> to memref<?xf32>
+  // CHECK-NEXT: getVariableName="input_data"
+
+  return
+}
diff --git a/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt b/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
index 1e593389ec683..a54b642d4db42 100644
--- a/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
+++ b/mlir/test/lib/Dialect/OpenACC/CMakeLists.txt
@@ -2,6 +2,7 @@ add_mlir_library(MLIROpenACCTestPasses
   TestOpenACC.cpp
   TestPointerLikeTypeInterface.cpp
   TestRecipePopulate.cpp
+  TestOpenACCSupport.cpp
   
   EXCLUDE_FROM_LIBMLIR
 )
@@ -11,6 +12,7 @@ mlir_target_link_libraries(MLIROpenACCTestPasses PUBLIC
   MLIRFuncDialect
   MLIRMemRefDialect
   MLIROpenACCDialect
+  MLIROpenACCAnalysis
   MLIRPass
   MLIRSupport
 )
diff --git a/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp b/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
index bea21b9827f7e..e59d77777ee40 100644
--- a/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
+++ b/mlir/test/lib/Dialect/OpenACC/TestOpenACC.cpp
@@ -16,11 +16,13 @@ namespace test {
 // Forward declarations of individual test pass registration functions
 void registerTestPointerLikeTypeInterfacePass();
 void registerTestRecipePopulatePass();
+void registerTestOpenACCSupportPass();
 
 // Unified registration function for all OpenACC tests
 void registerTestOpenACC() {
   registerTestPointerLikeTypeInterfacePass();
   registerTestRecipePopulatePass();
+  registerTestOpenACCSupportPass();
 }
 
 } // namespace test
diff --git a/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp b/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp
new file mode 100644
index 0000000000000..8bf984bdc2632
--- /dev/null
+++ b/mlir/test/lib/Dialect/OpenACC/TestOpenACCSupport.cpp
@@ -0,0 +1,73 @@
+//===- TestOpenACCSupport.cpp - Test OpenACCSupport Analysis -------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains test passes for testing the OpenACCSupport analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/MemRef/IR/MemRef.h"
+#include "mlir/Dialect/OpenACC/Analysis/OpenACCSupport.h"
+#include "mlir/Dialect/OpenACC/OpenACC.h"
+#include "mlir/Pass/Pass.h"
+
+using namespace mlir;
+using namespace mlir::acc;
+
+namespace {
+
+struct TestOpenACCSupportPass
+    : public PassWrapper<TestOpenACCSupportPass, OperationPass<func::FuncOp>> {
+  MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestOpenACCSupportPass)
+
+  StringRef getArgument() const override { return "test-acc-support"; }
+
+  StringRef getDescription() const override {
+    return "Test OpenACCSupport analysis";
+  }
+
+  void runOnOperation() override;
+
+  void getDependentDialects(DialectRegistry &registry) const override {
+    registry.insert<acc::OpenACCDialect>();
+    registry.insert<memref::MemRefDialect>();
+  }
+};
+
+void TestOpenACCSupportPass::runOnOperation() {
+  auto func = getOperation();
+
+  // Get the OpenACCSupport analysis
+  OpenACCSupport &support = getAnalysis<OpenACCSupport>();
+
+  // Walk through operations looking for test attributes
+  func.walk([&](Operation *op) {
+    // Check for test.var_name attribute. This is the marker used to identify
+    // the operations that need to be tested for getVariableName.
+    if (op->hasAttr("test.var_name")) {
+      // For each result of this operation, try to get the variable name
+      for (auto result : op->getResults()) {
+        std::string foundName = support.getVariableName(result);
+        llvm::outs() << "op=" << *op << "\n\tgetVariableName=\"" << foundName
+                     << "\"\n";
+      }
+    }
+  });
+}
+
+} // namespace
+
+namespace mlir {
+namespace test {
+
+void registerTestOpenACCSupportPass() {
+  PassRegistration<TestOpenACCSupportPass>();
+}
+
+} // namespace test
+} // namespace mlir
diff --git a/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp b/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
index ab817b640edb3..3fbbcc90a67c9 100644
--- a/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
+++ b/mlir/unittests/Dialect/OpenACC/OpenACCUtilsTest.cpp
@@ -410,3 +410,78 @@ TEST_F(OpenACCUtilsTest, getTypeCategoryArray) {
   VariableTypeCategory category = getTypeCategory(varPtr);
   EXPECT_EQ(category, VariableTypeCategory::array);
 }
+
+//===----------------------------------------------------------------------===//
+// getVariableName Tests
+//===----------------------------------------------------------------------===//
+
+TEST_F(OpenACCUtilsTest, getVariableNameDirect) {
+  // Create a memref with acc.var_name attribute
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  // Set the acc.var_name attribute
+  auto varNameAttr = VarNameAttr::get(&context, "my_variable");
+  allocOp.get()->setAttr(getVarNameAttrName(), varNameAttr);
+
+  Value varPtr = allocOp->getResult();
+
+  // Test that getVariableName returns the variable name
+  std::string varName = getVariableName(varPtr);
+  EXPECT_EQ(varName, "my_variable");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameThroughCast) {
+  // Create a 5x2 memref with acc.var_name attribute
+  auto memrefTy = MemRefType::get({5, 2}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  // Set the acc.var_name attribute on the alloca
+  auto varNameAttr = VarNameAttr::get(&context, "casted_variable");
+  allocOp.get()->setAttr(getVarNameAttrName(), varNameAttr);
+
+  Value allocResult = allocOp->getResult();
+
+  // Create a memref.cast operation to a flattened 10-element array
+  auto castedMemrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::CastOp> castOp =
+      memref::CastOp::create(b, loc, castedMemrefTy, allocResult);
+
+  Value castedPtr = castOp->getResult();
+
+  // Test that getVariableName walks through the cast to find the variable name
+  std::string varName = getVariableName(castedPtr);
+  EXPECT_EQ(varName, "casted_variable");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameNotFound) {
+  // Create a memref without acc.var_name attribute
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  Value varPtr = allocOp->getResult();
+
+  // Test that getVariableName returns empty string when no name is found
+  std::string varName = getVariableName(varPtr);
+  EXPECT_EQ(varName, "");
+}
+
+TEST_F(OpenACCUtilsTest, getVariableNameFromCopyin) {
+  // Create a memref
+  auto memrefTy = MemRefType::get({10}, b.getI32Type());
+  OwningOpRef<memref::AllocaOp> allocOp =
+      memref::AllocaOp::create(b, loc, memrefTy);
+
+  Value varPtr = allocOp->getResult();
+  StringRef name = "data_array";
+  OwningOpRef<CopyinOp> copyinOp =
+      CopyinOp::create(b, loc, varPtr, /*structured=*/true, /*implicit=*/true,
+                       /*name=*/name);
+
+  // Test that getVariableName extracts the name from the copyin operation
+  std::string varName = getVariableName(copyinOp->getAccVar());
+  EXPECT_EQ(varName, name);
+}

github-actions · 2025-10-21T22:37:05Z

✅ With the latest revision this PR passed the C/C++ code formatter.

vzakhari

Looks great! Thank you, Razvan!

clementval

LGTM

…#164729)

…164510) The OpenACC dialect must coexist with source language dialects (FIR, CIR, etc.) to enable offloading. While type interfaces (`PointerLikeType` and `MappableType`) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone. This commit introduces the `OpenACCSupport` analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's `AliasAnalysis` and is never invalidated, persisting throughout the pass pipeline. The initial API, `getVariableName(Value) -> string`, retrieves variable names from MLIR values by: - Checking for `acc.var_name` attributes - Extracting names from ACC data clause operations (e.g., `acc.copyin`) - Walking through `ViewLikeOpInterface` operations to find the source This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names. Usage: Passes call `getAnalysis<OpenACCSupport>()` to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling `setImplementation()` before the consumer pass runs.

…#164729)

…164510) The OpenACC dialect must coexist with source language dialects (FIR, CIR, etc.) to enable offloading. While type interfaces (`PointerLikeType` and `MappableType`) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone. This commit introduces the `OpenACCSupport` analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's `AliasAnalysis` and is never invalidated, persisting throughout the pass pipeline. The initial API, `getVariableName(Value) -> string`, retrieves variable names from MLIR values by: - Checking for `acc.var_name` attributes - Extracting names from ACC data clause operations (e.g., `acc.copyin`) - Walking through `ViewLikeOpInterface` operations to find the source This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names. Usage: Passes call `getAnalysis<OpenACCSupport>()` to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling `setImplementation()` before the consumer pass runs.

…#164729)

…164510) The OpenACC dialect must coexist with source language dialects (FIR, CIR, etc.) to enable offloading. While type interfaces (`PointerLikeType` and `MappableType`) provide the primary contract for variable mapping, some scenarios require pipeline-specific customization or need to express information that cannot be adequately captured through operation and type interfaces alone. This commit introduces the `OpenACCSupport` analysis, which provides extensible support APIs that can be customized per-pipeline. The analysis follows the Concept-Model pattern used in MLIR's `AliasAnalysis` and is never invalidated, persisting throughout the pass pipeline. The initial API, `getVariableName(Value) -> string`, retrieves variable names from MLIR values by: - Checking for `acc.var_name` attributes - Extracting names from ACC data clause operations (e.g., `acc.copyin`) - Walking through `ViewLikeOpInterface` operations to find the source This will be used in the implicit data mapping pass to automatically generate device mappings with correct user-visible variable names. Usage: Passes call `getAnalysis<OpenACCSupport>()` to get a cached instance with either the default or a previously- registered custom implementation. Custom implementations can be registered in a setup pass by calling `setImplementation()` before the consumer pass runs.

…#164729)

razvanlupusoru requested review from clementval, jeanPerier, rscottmanley and vzakhari October 21, 2025 22:35

llvmbot added mlir mlir:openacc openacc labels Oct 21, 2025

Fix formatting

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vzakhari approved these changes Oct 21, 2025

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clementval approved these changes Oct 21, 2025

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jeanPerier approved these changes Oct 22, 2025

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razvanlupusoru merged commit f3599e5 into llvm:main Oct 22, 2025
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googlewalt added a commit to googlewalt/llvm-project that referenced this pull request Oct 22, 2025

[bazel][mlir][acc] Port llvm#164510 to bazel

e5c3631

googlewalt added a commit that referenced this pull request Oct 22, 2025

[bazel][mlir][acc] Port #164510 to bazel (#164717)

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rnk added a commit to rnk/llvm-project that referenced this pull request Oct 22, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510

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rnk added a commit to rnk/llvm-project that referenced this pull request Oct 22, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510

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rnk added a commit that referenced this pull request Oct 22, 2025

[bazel] Add OpenACCUtils library, follow-up fix for #164510 (#164729)

6939b36

mikolaj-pirog pushed a commit to mikolaj-pirog/llvm-project that referenced this pull request Oct 23, 2025

[bazel][mlir][acc] Port llvm#164510 to bazel (llvm#164717)

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mikolaj-pirog pushed a commit to mikolaj-pirog/llvm-project that referenced this pull request Oct 23, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510 (llvm…

040e0a5

…#164729)

dvbuka pushed a commit to dvbuka/llvm-project that referenced this pull request Oct 27, 2025

[bazel][mlir][acc] Port llvm#164510 to bazel (llvm#164717)

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dvbuka pushed a commit to dvbuka/llvm-project that referenced this pull request Oct 27, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510 (llvm…

948e83d

…#164729)

Lukacma pushed a commit to Lukacma/llvm-project that referenced this pull request Oct 29, 2025

[bazel][mlir][acc] Port llvm#164510 to bazel (llvm#164717)

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Lukacma pushed a commit to Lukacma/llvm-project that referenced this pull request Oct 29, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510 (llvm…

6664256

…#164729)

aokblast pushed a commit to aokblast/llvm-project that referenced this pull request Oct 30, 2025

[bazel][mlir][acc] Port llvm#164510 to bazel (llvm#164717)

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aokblast pushed a commit to aokblast/llvm-project that referenced this pull request Oct 30, 2025

[bazel] Add OpenACCUtils library, follow-up fix for llvm#164510 (llvm…

0fdd382

…#164729)

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