[flang][FIR] add FirAliasAnalysisOpInterface (#68317)

This interface allows (HL)FIR passes to add TBAA information to fir.load
and fir.store. If present, these TBAA tags take precedence over those
added during CodeGen.

We can't reuse mlir::LLVMIR::AliasAnalysisOpInterface because that uses
the mlir::LLVMIR namespace so it tries to define methods for fir
operations in the wrong namespace. But I did re-use the tbaa tag type to
minimise boilerplate code.

The new builders are to preserve the old interface without the tbaa tag.

Author: tblah

flang/include/flang/Optimizer/Dialect/CMakeLists.txt

@@ -18,6 +18,10 @@ set(LLVM_TARGET_DEFINITIONS FortranVariableInterface.td)
 mlir_tablegen(FortranVariableInterface.h.inc -gen-op-interface-decls)
 mlir_tablegen(FortranVariableInterface.cpp.inc -gen-op-interface-defs)
 
+set(LLVM_TARGET_DEFINITIONS FirAliasTagOpInterface.td)
+mlir_tablegen(FirAliasTagOpInterface.h.inc -gen-op-interface-decls)
+mlir_tablegen(FirAliasTagOpInterface.cpp.inc -gen-op-interface-defs)
+
 set(LLVM_TARGET_DEFINITIONS CanonicalizationPatterns.td)
 mlir_tablegen(CanonicalizationPatterns.inc -gen-rewriters)
 add_public_tablegen_target(CanonicalizationPatternsIncGen)

flang/include/flang/Optimizer/Dialect/FIRDialect.td

@@ -30,7 +30,9 @@ def fir_Dialect : Dialect {
   let dependentDialects = [
     // Arith dialect provides FastMathFlagsAttr
     // supported by some FIR operations.
-    "arith::ArithDialect"
+    "arith::ArithDialect",
+    // TBAA Tag types
+    "LLVM::LLVMDialect"
   ];
 }
 

flang/include/flang/Optimizer/Dialect/FIROps.h

@@ -11,6 +11,7 @@
 
 #include "flang/Optimizer/Dialect/FIRAttr.h"
 #include "flang/Optimizer/Dialect/FIRType.h"
+#include "flang/Optimizer/Dialect/FirAliasTagOpInterface.h"
 #include "flang/Optimizer/Dialect/FortranVariableInterface.h"
 #include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"

flang/include/flang/Optimizer/Dialect/FIROps.td

@@ -16,10 +16,12 @@
 
 include "mlir/Dialect/Arith/IR/ArithBase.td"
 include "mlir/Dialect/Arith/IR/ArithOpsInterfaces.td"
+include "mlir/Dialect/LLVMIR/LLVMAttrDefs.td"
 include "flang/Optimizer/Dialect/FIRDialect.td"
 include "flang/Optimizer/Dialect/FIRTypes.td"
 include "flang/Optimizer/Dialect/FIRAttr.td"
 include "flang/Optimizer/Dialect/FortranVariableInterface.td"
+include "flang/Optimizer/Dialect/FirAliasTagOpInterface.td"
 include "mlir/IR/BuiltinAttributes.td"
 
 // Base class for FIR operations.
@@ -258,7 +260,7 @@ def fir_FreeMemOp : fir_Op<"freemem", [MemoryEffects<[MemFree]>]> {
   let assemblyFormat = "$heapref attr-dict `:` qualified(type($heapref))";
 }
 
-def fir_LoadOp : fir_OneResultOp<"load", []> {
+def fir_LoadOp : fir_OneResultOp<"load", [FirAliasTagOpInterface]> {
   let summary = "load a value from a memory reference";
   let description = [{
     Load a value from a memory reference into an ssa-value (virtual register).
@@ -274,9 +276,11 @@ def fir_LoadOp : fir_OneResultOp<"load", []> {
     or null.
   }];
 
-  let arguments = (ins Arg<AnyReferenceLike, "", [MemRead]>:$memref);
+  let arguments = (ins Arg<AnyReferenceLike, "", [MemRead]>:$memref,
+                  OptionalAttr<LLVM_TBAATagArrayAttr>:$tbaa);
 
-  let builders = [OpBuilder<(ins "mlir::Value":$refVal)>];
+  let builders = [OpBuilder<(ins "mlir::Value":$refVal)>,
+                  OpBuilder<(ins "mlir::Type":$resTy, "mlir::Value":$refVal)>];
 
   let hasCustomAssemblyFormat = 1;
 
@@ -285,7 +289,7 @@ def fir_LoadOp : fir_OneResultOp<"load", []> {
   }];
 }
 
-def fir_StoreOp : fir_Op<"store", []> {
+def fir_StoreOp : fir_Op<"store", [FirAliasTagOpInterface]> {
   let summary = "store an SSA-value to a memory location";
 
   let description = [{
@@ -305,7 +309,10 @@ def fir_StoreOp : fir_Op<"store", []> {
   }];
 
   let arguments = (ins AnyType:$value,
-                   Arg<AnyReferenceLike, "", [MemWrite]>:$memref);
+                   Arg<AnyReferenceLike, "", [MemWrite]>:$memref,
+                   OptionalAttr<LLVM_TBAATagArrayAttr>:$tbaa);
+
+  let builders = [OpBuilder<(ins "mlir::Value":$value, "mlir::Value":$memref)>];
 
   let hasCustomAssemblyFormat = 1;
   let hasVerifier = 1;

flang/include/flang/Optimizer/Dialect/FirAliasTagOpInterface.h

@@ -0,0 +1,27 @@
+//===- FirAliasTagOpInterface.h ---------------------------------*- 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 contains an interface for adding alias analysis information to
+// loads and stores
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_DIALECT_FIR_ALIAS_TAG_OP_INTERFACE_H
+#define FORTRAN_OPTIMIZER_DIALECT_FIR_ALIAS_TAG_OP_INTERFACE_H
+
+#include "mlir/IR/OpDefinition.h"
+#include "mlir/IR/Operation.h"
+#include "mlir/Support/LogicalResult.h"
+
+namespace fir::detail {
+mlir::LogicalResult verifyFirAliasTagOpInterface(mlir::Operation *op);
+} // namespace fir::detail
+
+#include "flang/Optimizer/Dialect/FirAliasTagOpInterface.h.inc"
+
+#endif // FORTRAN_OPTIMIZER_DIALECT_FIR_ALIAS_TAG_OP_INTERFACE_H

flang/include/flang/Optimizer/Dialect/FirAliasTagOpInterface.td

@@ -0,0 +1,59 @@
+//===-- FirAliasTagOpInterface.td --------------------------*- tablegen -*-===//
+//
+// 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/IR/Interfaces.td"
+
+def FirAliasTagOpInterface : OpInterface<"FirAliasTagOpInterface"> {
+  let description = [{
+    An interface for memory operations that can carry alias analysis metadata.
+    It provides setters and getters for the operation's alias analysis
+    attributes. The default implementations of the interface methods expect
+    the operation to have an attribute of type ArrayAttr named tbaa.
+    Unlike the mlir::LLVM::AliasAnalysisOpInterface, this only supports tbaa.
+  }];
+
+  let cppNamespace = "::fir";
+  let verify = [{ return detail::verifyFirAliasTagOpInterface($_op); }];
+
+  let methods = [
+    InterfaceMethod<
+      /*desc=*/        "Returns the tbaa attribute or nullptr",
+      /*returnType=*/  "mlir::ArrayAttr",
+      /*methodName=*/  "getTBAATagsOrNull",
+      /*args=*/        (ins),
+      /*methodBody=*/  [{}],
+      /*defaultImpl=*/ [{
+        auto op = mlir::cast<ConcreteOp>(this->getOperation());
+        return op.getTbaaAttr();
+      }]
+      >,
+    InterfaceMethod<
+      /*desc=*/        "Sets the tbaa attribute",
+      /*returnType=*/  "void",
+      /*methodName=*/  "setTBAATags",
+      /*args=*/        (ins "const mlir::ArrayAttr":$attr),
+      /*methodBody=*/  [{}],
+      /*defaultImpl=*/ [{
+        auto op = mlir::cast<ConcreteOp>(this->getOperation());
+        op.setTbaaAttr(attr);
+      }]
+      >,
+    InterfaceMethod<
+      /*desc=*/        "Returns a list of all pointer operands accessed by the "
+                       "operation",
+      /*returnType=*/  "::llvm::SmallVector<::mlir::Value>",
+      /*methodName=*/  "getAccessedOperands",
+      /*args=*/        (ins),
+      /*methodBody=*/  [{}],
+      /*defaultImpl=*/ [{
+        auto op = mlir::cast<ConcreteOp>(this->getOperation());
+        return {op.getMemref()};
+      }]
+      >
+  ];
+}

flang/lib/Optimizer/CodeGen/CodeGen.cpp

@@ -3086,7 +3086,10 @@ struct LoadOpConversion : public FIROpConversion<fir::LoadOp> {
       auto boxValue = rewriter.create<mlir::LLVM::LoadOp>(
           loc, boxPtrTy.cast<mlir::LLVM::LLVMPointerType>().getElementType(),
           inputBoxStorage);
-      attachTBAATag(boxValue, boxTy, boxTy, nullptr);
+      if (std::optional<mlir::ArrayAttr> optionalTag = load.getTbaa())
+        boxValue.setTBAATags(*optionalTag);
+      else
+        attachTBAATag(boxValue, boxTy, boxTy, nullptr);
       auto newBoxStorage =
           genAllocaWithType(loc, boxPtrTy, defaultAlign, rewriter);
       auto storeOp =
@@ -3097,7 +3100,10 @@ struct LoadOpConversion : public FIROpConversion<fir::LoadOp> {
       mlir::Type loadTy = convertType(load.getType());
       auto loadOp = rewriter.create<mlir::LLVM::LoadOp>(
           load.getLoc(), loadTy, adaptor.getOperands(), load->getAttrs());
-      attachTBAATag(loadOp, load.getType(), load.getType(), nullptr);
+      if (std::optional<mlir::ArrayAttr> optionalTag = load.getTbaa())
+        loadOp.setTBAATags(*optionalTag);
+      else
+        attachTBAATag(loadOp, load.getType(), load.getType(), nullptr);
       rewriter.replaceOp(load, loadOp.getResult());
     }
     return mlir::success();
@@ -3341,7 +3347,10 @@ struct StoreOpConversion : public FIROpConversion<fir::StoreOp> {
       newStoreOp = rewriter.create<mlir::LLVM::StoreOp>(
           loc, adaptor.getOperands()[0], adaptor.getOperands()[1]);
     }
-    attachTBAATag(newStoreOp, storeTy, storeTy, nullptr);
+    if (std::optional<mlir::ArrayAttr> optionalTag = store.getTbaa())
+      newStoreOp.setTBAATags(*optionalTag);
+    else
+      attachTBAATag(newStoreOp, storeTy, storeTy, nullptr);
     rewriter.eraseOp(store);
     return mlir::success();
   }

flang/lib/Optimizer/Dialect/CMakeLists.txt

@@ -6,6 +6,7 @@ add_flang_library(FIRDialect
   FIROps.cpp
   FIRType.cpp
   FortranVariableInterface.cpp
+  FirAliasTagOpInterface.cpp
   Inliner.cpp
 
   DEPENDS

flang/lib/Optimizer/Dialect/FIRDialect.cpp

@@ -14,6 +14,7 @@
 #include "flang/Optimizer/Dialect/FIRAttr.h"
 #include "flang/Optimizer/Dialect/FIROps.h"
 #include "flang/Optimizer/Dialect/FIRType.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Transforms/InliningUtils.h"
 
 using namespace fir;
@@ -58,6 +59,7 @@ struct FIRInlinerInterface : public mlir::DialectInlinerInterface {
 
 fir::FIROpsDialect::FIROpsDialect(mlir::MLIRContext *ctx)
     : mlir::Dialect("fir", ctx, mlir::TypeID::get<FIROpsDialect>()) {
+  getContext()->loadDialect<mlir::LLVM::LLVMDialect>();
   registerTypes();
   registerAttributes();
   addOperations<

flang/lib/Optimizer/Dialect/FIROps.cpp

@@ -1977,8 +1977,18 @@ void fir::LoadOp::build(mlir::OpBuilder &builder, mlir::OperationState &result,
     mlir::emitError(result.location, "not a memory reference type");
     return;
   }
+  build(builder, result, eleTy, refVal);
+}
+
+void fir::LoadOp::build(mlir::OpBuilder &builder, mlir::OperationState &result,
+                        mlir::Type resTy, mlir::Value refVal) {
+
+  if (!refVal) {
+    mlir::emitError(result.location, "LoadOp has null argument");
+    return;
+  }
   result.addOperands(refVal);
-  result.addTypes(eleTy);
+  result.addTypes(resTy);
 }
 
 mlir::ParseResult fir::LoadOp::getElementOf(mlir::Type &ele, mlir::Type ref) {
@@ -3249,6 +3259,11 @@ mlir::LogicalResult fir::StoreOp::verify() {
   return mlir::success();
 }
 
+void fir::StoreOp::build(mlir::OpBuilder &builder, mlir::OperationState &result,
+                         mlir::Value value, mlir::Value memref) {
+  build(builder, result, value, memref, {});
+}
+
 //===----------------------------------------------------------------------===//
 // StringLitOp
 //===----------------------------------------------------------------------===//

flang/lib/Optimizer/Dialect/FirAliasTagOpInterface.cpp

@@ -0,0 +1,31 @@
+//===-- FirAliasTagOpInterface.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
+//
+//===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Optimizer/Dialect/FirAliasTagOpInterface.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+
+#include "flang/Optimizer/Dialect/FirAliasTagOpInterface.cpp.inc"
+
+mlir::LogicalResult
+fir::detail::verifyFirAliasTagOpInterface(mlir::Operation *op) {
+  auto iface = mlir::cast<FirAliasTagOpInterface>(op);
+
+  mlir::ArrayAttr tags = iface.getTBAATagsOrNull();
+  if (!tags)
+    return mlir::success();
+
+  for (mlir::Attribute iter : tags)
+    if (!mlir::isa<mlir::LLVM::TBAATagAttr>(iter))
+      return op->emitOpError("expected op to return array of ")
+             << mlir::LLVM::TBAATagAttr::getMnemonic() << " attributes";
+  return mlir::success();
+}

flang/test/Fir/tbaa-codegen.fir

@@ -0,0 +1,47 @@
+// test that tbaa attributes can be added to fir.load and fir.store
+// and that these attributes are propagated to LLVMIR
+
+// RUN: tco %s | FileCheck %s
+
+// subroutine simple(a)
+//   integer, intent(inout) :: a(:)
+//   a(1) = a(2)
+// end subroutine
+#tbaa_root = #llvm.tbaa_root<id = "Flang function root _QPsimple">
+#tbaa_type_desc = #llvm.tbaa_type_desc<id = "any access", members = {<#tbaa_root, 0>}>
+#tbaa_type_desc1 = #llvm.tbaa_type_desc<id = "any data access", members = {<#tbaa_type_desc, 0>}>
+#tbaa_type_desc2 = #llvm.tbaa_type_desc<id = "dummy arg data", members = {<#tbaa_type_desc1, 0>}>
+#tbaa_type_desc3 = #llvm.tbaa_type_desc<id = "dummy arg data/a", members = {<#tbaa_type_desc2, 0>}>
+#tbaa_tag = #llvm.tbaa_tag<base_type = #tbaa_type_desc3, access_type = #tbaa_type_desc3, offset = 0>
+module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.target_triple = "aarch64-unknown-linux-gnu"} {
+  func.func @_QPsimple(%arg0: !fir.box<!fir.array<?xi32>> {fir.bindc_name = "a"}) {
+    %c1 = arith.constant 1 : index
+    %c2 = arith.constant 2 : index
+    %0 = fir.declare %arg0 {fortran_attrs = #fir.var_attrs<intent_inout>, uniq_name = "_QFfuncEa"} : (!fir.box<!fir.array<?xi32>>) -> !fir.box<!fir.array<?xi32>>
+    %1 = fir.rebox %0 : (!fir.box<!fir.array<?xi32>>) -> !fir.box<!fir.array<?xi32>>
+    %2 = fir.array_coor %1 %c2 : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+    %3 = fir.load %2 {tbaa = [#tbaa_tag]} : !fir.ref<i32>
+    %4 = fir.array_coor %1 %c1 : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+    fir.store %3 to %4 {tbaa = [#tbaa_tag]} : !fir.ref<i32>
+    return
+  }
+}
+
+// CHECK-LABEL: define void @_QPsimple(
+// CHECK-SAME:      ptr %[[ARG0:.*]]) {
+// [...]
+// load  a(2):
+// CHECK:  %[[VAL20:.*]] = getelementptr i8, ptr %{{.*}}, i64 %{{.*}}
+// CHECK:  %[[A2:.*]] = load i32, ptr %[[VAL20]], align 4, !tbaa ![[A_ACCESS_TAG:.*]]
+// [...]
+// store a(2) to a(1):
+// CHECK:  %[[A1:.*]] = getelementptr i8, ptr %{{.*}}, i64 %{{.*}}
+// CHECK:  store i32 %[[A2]], ptr %[[A1]], align 4, !tbaa ![[A_ACCESS_TAG]]
+// CHECK:  ret void
+// CHECK: }
+// CHECK: ![[A_ACCESS_TAG]] = !{![[A_ACCESS_TYPE:.*]], ![[A_ACCESS_TYPE]], i64 0}
+// CHECK: ![[A_ACCESS_TYPE]] = !{!"dummy arg data/a", ![[DUMMY_ARG_TYPE:.*]], i64 0}
+// CHECK: ![[DUMMY_ARG_TYPE]] = !{!"dummy arg data", ![[DATA_ACCESS_TYPE:.*]], i64 0}
+// CHECK: ![[DATA_ACCESS_TYPE]] = !{!"any data access", ![[ANY_ACCESS_TYPE:.*]], i64 0}
+// CHECK: ![[ANY_ACCESS_TYPE]] = !{!"any access", ![[ROOT:.*]], i64 0}
+// CHECK: ![[ROOT]] = !{!"Flang function root _QPsimple"}