Alias Analysis infra in Flang

Differential revision: https://reviews.llvm.org/D136889

flang/CMakeLists.txt

@@ -411,6 +411,9 @@ endif()
 include(CMakeParseArguments)
 include(AddFlang)
 
+if (FLANG_INCLUDE_TESTS)
+  add_compile_definitions(FLANG_INCLUDE_TESTS=1)
+endif()
 
 add_subdirectory(include)
 add_subdirectory(lib)

flang/include/flang/Optimizer/Analysis/AliasAnalysis.h

@@ -0,0 +1,29 @@
+//===- AliasAnalysis.h - Alias Analysis in FIR -----------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FIR_ANALYSIS_ALIASANALYSIS_H_
+#define FIR_ANALYSIS_ALIASANALYSIS_H_
+
+#include "mlir/Analysis/AliasAnalysis.h"
+
+namespace fir {
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis
+//===----------------------------------------------------------------------===//
+class AliasAnalysis {
+public:
+  /// Given two values, return their aliasing behavior.
+  mlir::AliasResult alias(mlir::Value lhs, mlir::Value rhs);
+
+  /// Return the modify-reference behavior of `op` on `location`.
+  mlir::ModRefResult getModRef(mlir::Operation *op, mlir::Value location);
+};
+} // namespace fir
+
+#endif // FIR_ANALYSIS_ALIASANALYSIS_H_

flang/lib/Lower/IntrinsicCall.cpp

@@ -5004,7 +5004,7 @@ Fortran::lower::getIntrinsicArgumentLowering(llvm::StringRef specificName) {
 /// intrinsic function.
 Fortran::lower::ArgLoweringRule Fortran::lower::lowerIntrinsicArgumentAs(
     const IntrinsicArgumentLoweringRules &rules, unsigned position) {
-  assert(position < sizeof(rules.args) / sizeof(decltype(*rules.args)) &&
+  assert(position < sizeof(rules.args) / (sizeof(decltype(*rules.args))) &&
          "invalid argument");
   return {rules.args[position].lowerAs,
           rules.args[position].handleDynamicOptional};

flang/lib/Optimizer/Analysis/AliasAnalysis.cpp

@@ -0,0 +1,67 @@
+//===- AliasAnalysis.cpp - Alias Analysis for FIR  ------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Optimizer/Analysis/AliasAnalysis.h"
+#include "mlir/Interfaces/SideEffectInterfaces.h"
+
+using namespace mlir;
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis: alias
+//===----------------------------------------------------------------------===//
+
+namespace fir {
+AliasResult AliasAnalysis::alias(Value lhs, Value rhs) {
+  // This is for now a mock analysis
+  if (lhs == rhs) {
+    return AliasResult::MustAlias;
+  }
+  return AliasResult::MayAlias;
+}
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis: getModRef
+//===----------------------------------------------------------------------===//
+
+/// This is mostly inspired by MLIR::LocalAliasAnalysis with 2 notable
+/// differences 1) Regions are not handled here but will be handled by a data
+/// flow analysis to come 2) Allocate and Free effects are considered modifying
+ModRefResult AliasAnalysis::getModRef(Operation *op, Value location) {
+  MemoryEffectOpInterface interface = dyn_cast<MemoryEffectOpInterface>(op);
+  if (!interface)
+    return ModRefResult::getModAndRef();
+
+  // Build a ModRefResult by merging the behavior of the effects of this
+  // operation.
+  SmallVector<MemoryEffects::EffectInstance> effects;
+  interface.getEffects(effects);
+
+  ModRefResult result = ModRefResult::getNoModRef();
+  for (const MemoryEffects::EffectInstance &effect : effects) {
+
+    // Check for an alias between the effect and our memory location.
+    AliasResult aliasResult = AliasResult::MayAlias;
+    if (Value effectValue = effect.getValue())
+      aliasResult = alias(effectValue, location);
+
+    // If we don't alias, ignore this effect.
+    if (aliasResult.isNo())
+      continue;
+
+    // Merge in the corresponding mod or ref for this effect.
+    if (isa<MemoryEffects::Read>(effect.getEffect())) {
+      result = result.merge(ModRefResult::getRef());
+    } else {
+      result = result.merge(ModRefResult::getMod());
+    }
+    if (result.isModAndRef())
+      break;
+  }
+  return result;
+}
+} // namespace fir

flang/lib/Optimizer/Analysis/CMakeLists.txt

@@ -0,0 +1,16 @@
+add_flang_library(FIRAnalysis
+  AliasAnalysis.cpp
+
+  DEPENDS
+  FIRBuilder
+  FIRDialect
+  FIRSupport
+
+  LINK_LIBS
+  FIRBuilder
+  FIRDialect
+  MLIRFuncDialect
+  MLIRLLVMDialect
+  MLIRMathTransforms
+  FIRSupport
+)

flang/lib/Optimizer/CMakeLists.txt

@@ -4,3 +4,4 @@ add_subdirectory(Dialect)
 add_subdirectory(HLFIR)
 add_subdirectory(Support)
 add_subdirectory(Transforms)
+add_subdirectory(Analysis)

flang/test/CMakeLists.txt

@@ -1,5 +1,6 @@
 # Test runner infrastructure for Flang. This configures the Flang test trees
 # for use by Lit, and delegates to LLVM's lit test handlers.
+add_subdirectory(lib)
 
 llvm_canonicalize_cmake_booleans(
   FLANG_BUILD_EXAMPLES

flang/test/lib/Analysis/AliasAnalysis/CMakeLists.txt

@@ -0,0 +1,29 @@
+# Exclude tests from libMLIR.so
+add_flang_library(FIRTestAnalysis
+  TestAliasAnalysis.cpp
+
+  DEPENDS
+  FIRDialect
+  FIRBuilder
+  FIRSupport
+  FIRTransforms
+  FIRAnalysis
+  ${dialect_libs}
+
+  LINK_LIBS
+  FIRDialect
+  FIRBuilder
+  FIRSupport
+  FIRTransforms
+  FIRAnalysis
+  ${dialect_libs}
+  MLIRFuncDialect
+  MLIRLLVMDialect
+  MLIRAnalysis
+  MLIRTestAnalysis
+  )
+
+target_include_directories(FIRTestAnalysis
+  PRIVATE
+  ${MLIR_MAIN_SRC_DIR}/..
+  )

flang/test/lib/Analysis/AliasAnalysis/TestAliasAnalysis.cpp

@@ -0,0 +1,72 @@
+//===- TestAliasAnalysis.cpp - Test FIR lias 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/test/lib/Analysis/TestAliasAnalysis.h"
+#include "mlir/Analysis/AliasAnalysis.h"
+#include "mlir/Pass/Pass.h"
+#include "flang/Optimizer/Analysis/AliasAnalysis.h"
+
+using namespace mlir;
+
+namespace {
+
+//===----------------------------------------------------------------------===//
+// Testing AliasResult
+//===----------------------------------------------------------------------===//
+
+struct TestFIRAliasAnalysisPass
+    : public test::TestAliasAnalysisBase,
+      PassWrapper<TestFIRAliasAnalysisPass, OperationPass<>> {
+  MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestFIRAliasAnalysisPass)
+
+  StringRef getArgument() const final { return "test-fir-alias-analysis"; }
+  StringRef getDescription() const final {
+    return "Test alias analysis results.";
+  }
+  void runOnOperation() override {
+    mlir::AliasAnalysis aliasAnalysis(getOperation());
+    aliasAnalysis.addAnalysisImplementation(fir::AliasAnalysis());
+    runAliasAnalysisOnOperation(getOperation(), aliasAnalysis);
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// Testing ModRefResult
+//===----------------------------------------------------------------------===//
+
+struct TestFIRAliasAnalysisModRefPass
+    : public test::TestAliasAnalysisModRefBase,
+      PassWrapper<TestFIRAliasAnalysisModRefPass, OperationPass<>> {
+  MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestFIRAliasAnalysisModRefPass)
+
+  StringRef getArgument() const final {
+    return "test-fir-alias-analysis-modref";
+  }
+  StringRef getDescription() const final {
+    return "Test alias analysis ModRef results.";
+  }
+  void runOnOperation() override {
+    mlir::AliasAnalysis aliasAnalysis(getOperation());
+    aliasAnalysis.addAnalysisImplementation(fir::AliasAnalysis());
+    runAliasAnalysisOnOperation(getOperation(), aliasAnalysis);
+  }
+};
+} // namespace
+
+//===----------------------------------------------------------------------===//
+// Pass Registration
+//===----------------------------------------------------------------------===//
+
+namespace fir {
+namespace test {
+void registerTestFIRAliasAnalysisPass() {
+  PassRegistration<TestFIRAliasAnalysisPass>();
+  PassRegistration<TestFIRAliasAnalysisModRefPass>();
+}
+} // namespace test
+} // namespace fir

flang/test/lib/Analysis/AliasAnalysis/alias-analysis-1.fir

@@ -0,0 +1,21 @@
+// RUN: fir-opt %s -pass-pipeline='builtin.module(func.func(test-fir-alias-analysis))' -split-input-file 2>&1 | FileCheck %s
+
+// CHECK-LABEL: Testing : "_QPtest"
+// CHECK-DAG: alloca_1#0 <-> address_of#0: MayAlias
+func.func @_QPtest(%arg1: !fir.ref<i32>) {
+  %c1_i32 = arith.constant 1 : i32
+  %0 = fir.alloca () -> () {test.ptr = "alloca_1"}
+  %1 = fir.address_of(@_QPf) {test.ptr = "address_of"} : () -> i32 
+  %2 = fir.convert %1 : (() -> i32) -> (() -> ())
+  %4 = fir.convert %0 : (!fir.ref<() -> ()>) -> !fir.llvm_ptr<() -> ()>
+  fir.store %2 to %4 : !fir.llvm_ptr<() -> ()>
+  %6 = fir.load %0 : !fir.ref<() -> ()>
+  fir.call @_QPs(%6) : (() -> ()) -> ()
+  return
+}
+
+// -----
+func.func private @_QPs(%arg0: () -> ()) 
+
+// -----
+func.func private @_QPf() -> i32

flang/test/lib/Analysis/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(AliasAnalysis)

flang/test/lib/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(Analysis)

flang/test/lib/lit.local.cfg

@@ -0,0 +1,7 @@
+
+# Excluding .cpp file from the extensions since from this level down they are used for the development 
+config.suffixes = ['.c', '.f', '.F', '.ff', '.FOR', '.for', '.f77', '.f90', '.F90',
+                   '.ff90', '.f95', '.F95', '.ff95', '.fpp', '.FPP', '.cuf'
+                   '.CUF', '.f18', '.F18', '.f03', '.F03', '.f08', '.F08',
+                   '.ll', '.fir', '.mlir']
+

flang/tools/fir-opt/CMakeLists.txt

@@ -2,12 +2,20 @@ add_flang_tool(fir-opt fir-opt.cpp)
 llvm_update_compile_flags(fir-opt)
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
 
+if(FLANG_INCLUDE_TESTS)
+  set(test_libs
+    FIRTestAnalysis
+    )
+endif()
+
 target_link_libraries(fir-opt PRIVATE
   FIRDialect
   FIRSupport
   FIRTransforms
   FIRCodeGen
   HLFIRDialect
+  FIRAnalysis
+  ${test_libs}
   ${dialect_libs}
 
   # TODO: these should be transitive dependencies from a target providing

flang/tools/fir-opt/fir-opt.cpp

@@ -17,11 +17,19 @@
 #include "flang/Optimizer/Transforms/Passes.h"
 
 using namespace mlir;
+namespace fir {
+namespace test {
+void registerTestFIRAliasAnalysisPass();
+} // namespace test
+} // namespace fir
 
 int main(int argc, char **argv) {
   fir::support::registerMLIRPassesForFortranTools();
   fir::registerOptCodeGenPasses();
   fir::registerOptTransformPasses();
+#ifdef FLANG_INCLUDE_TESTS
+  fir::test::registerTestFIRAliasAnalysisPass();
+#endif
   DialectRegistry registry;
   fir::support::registerDialects(registry);
   return failed(MlirOptMain(argc, argv, "FIR modular optimizer driver\n",