[MLIR][ODS] Make dialect attribute helper member functions const (NFC)

[Dinistro]

This commit marks member functions of dialect attribute helpers as constant. This ensures that these helpers can be used as members of rewrite patterns, whose matchAndRewrite functions are marked as const as well.

[llvmbot]

@llvm/pr-subscribers-mlir

Author: Christian Ulmann (Dinistro)

Changes

This commit marks member functions of dialect attribute helpers as constant. This ensures that these helpers can be used as members of rewrite patterns, whose matchAndRewrite functions are marked as const as well.

---

Full diff: https://github.com/llvm/llvm-project/pull/181111.diff

1 Files Affected:

• (modified) mlir/tools/mlir-tblgen/DialectGen.cpp (+6-6)

diff --git a/mlir/tools/mlir-tblgen/DialectGen.cpp b/mlir/tools/mlir-tblgen/DialectGen.cpp
index c2c0c1f415254..8eecad39f49f3 100644
--- a/mlir/tools/mlir-tblgen/DialectGen.cpp
+++ b/mlir/tools/mlir-tblgen/DialectGen.cpp
@@ -207,23 +207,23 @@ static const char *const discardableAttrHelperDecl = R"(
       static constexpr ::llvm::StringLiteral getNameStr() {{
         return "{4}.{1}";
       }
-      constexpr ::mlir::StringAttr getName() {{
+      constexpr ::mlir::StringAttr getName() const {{
         return name;
       }
 
-      {0}AttrHelper(::mlir::MLIRContext *ctx)
+      explicit {0}AttrHelper(::mlir::MLIRContext *ctx)
         : name(::mlir::StringAttr::get(ctx, getNameStr())) {{}
 
-     {2} getAttr(::mlir::Operation *op) {{
+     {2} getAttr(::mlir::Operation *op) const {{
        return op->getAttrOfType<{2}>(name);
      }
-     void setAttr(::mlir::Operation *op, {2} val) {{
+     void setAttr(::mlir::Operation *op, {2} val) const {{
        op->setAttr(name, val);
      }
-     bool isAttrPresent(::mlir::Operation *op) {{
+     bool isAttrPresent(::mlir::Operation *op) const {{
        return op->hasAttrOfType<{2}>(name);
      }
-     void removeAttr(::mlir::Operation *op) {{
+     void removeAttr(::mlir::Operation *op) const {{
        assert(op->hasAttrOfType<{2}>(name));
        op->removeAttr(name);
      }

[llvmbot]

@llvm/pr-subscribers-mlir-core

Author: Christian Ulmann (Dinistro)

Changes

This commit marks member functions of dialect attribute helpers as constant. This ensures that these helpers can be used as members of rewrite patterns, whose matchAndRewrite functions are marked as const as well.

---

Full diff: https://github.com/llvm/llvm-project/pull/181111.diff

1 Files Affected:

• (modified) mlir/tools/mlir-tblgen/DialectGen.cpp (+6-6)

diff --git a/mlir/tools/mlir-tblgen/DialectGen.cpp b/mlir/tools/mlir-tblgen/DialectGen.cpp
index c2c0c1f415254..8eecad39f49f3 100644
--- a/mlir/tools/mlir-tblgen/DialectGen.cpp
+++ b/mlir/tools/mlir-tblgen/DialectGen.cpp
@@ -207,23 +207,23 @@ static const char *const discardableAttrHelperDecl = R"(
       static constexpr ::llvm::StringLiteral getNameStr() {{
         return "{4}.{1}";
       }
-      constexpr ::mlir::StringAttr getName() {{
+      constexpr ::mlir::StringAttr getName() const {{
         return name;
       }
 
-      {0}AttrHelper(::mlir::MLIRContext *ctx)
+      explicit {0}AttrHelper(::mlir::MLIRContext *ctx)
         : name(::mlir::StringAttr::get(ctx, getNameStr())) {{}
 
-     {2} getAttr(::mlir::Operation *op) {{
+     {2} getAttr(::mlir::Operation *op) const {{
        return op->getAttrOfType<{2}>(name);
      }
-     void setAttr(::mlir::Operation *op, {2} val) {{
+     void setAttr(::mlir::Operation *op, {2} val) const {{
        op->setAttr(name, val);
      }
-     bool isAttrPresent(::mlir::Operation *op) {{
+     bool isAttrPresent(::mlir::Operation *op) const {{
        return op->hasAttrOfType<{2}>(name);
      }
-     void removeAttr(::mlir::Operation *op) {{
+     void removeAttr(::mlir::Operation *op) const {{
        assert(op->hasAttrOfType<{2}>(name));
        op->removeAttr(name);
      }

[matthias-springer]

these helpers can be used as members of rewrite patterns

What does that mean? Can you post a small example of what does not compile?

[Dinistro]

these helpers can be used as members of rewrite patterns

What does that mean? Can you post a small example of what does not compile?

Sure, sorry for not adding it right away. Something like this does not work:

struct ExamplePattern : public OpConversionPattern<MyDialect::MyOp> {
  using Base::OpConversionPattern;

  ExamplePattern(MLIRContext *context) : Base(context), helper(context) {}

  LogicalResult
  matchAndRewrite(MyDialect::MyOpop, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    // Does not compile, because `setAttr` is not const.              
    helper.setAttr(op, rewriter.getUnitAttr());
    return success();
  }
  
  MyDialect::MyAttrHelper helper;
};