Define mAttr in terms of AttrConstraint.

* Matching an attribute and specifying a attribute constraint is the same thing executionally, so represent it such.
* Extract AttrConstraint helper to match TypeConstraint and use that where mAttr was previously used in RewriterGen.

PiperOrigin-RevId: 231213580

mlir/include/mlir/IR/op_base.td

@@ -221,7 +221,7 @@ def FloatLike : TypeConstraint<AnyOf<[Float.predicate,
 // A constraint on attributes. This can be used to check the validity of
 // instruction attributes.
 class AttrConstraint<Pred condition> {
-  // The predicates that this type satisfies.
+  // The predicates that this attribute satisfies.
   // Format: {0} will be expanded to the attribute.
   Pred predicate = condition;
 }
@@ -443,11 +443,7 @@ class Pat<dag pattern, dag result> : Pattern<pattern, [result]>;
 
 // Attribute matcher. This is the base class to specify a predicate
 // that has to match. Used on the input attributes of a rewrite rule.
-class mAttr<CPred pred> {
-  // Code to match the attribute.
-  // Format: {0} represents the attribute.
-  CPred predicate = pred;
-}
+class mAttr<Pred pred> : AttrConstraint<pred>;
 
 // Attribute transforms. This is the base class to specify a
 // transformation of a matched attribute. Used on the output of a rewrite

mlir/include/mlir/TableGen/Attribute.h

@@ -35,13 +35,37 @@ class Record;
 namespace mlir {
 namespace tblgen {
 
+// Wrapper class with helper methods for accessing Attribute constraints defined
+// in TableGen.
+class AttrConstraint {
+public:
+  explicit AttrConstraint(const llvm::Record *record);
+  explicit AttrConstraint(const llvm::DefInit *init);
+
+  // Returns the predicate that can be used to check if a attribute satisfies
+  // this attribute constraint.
+  Pred getPredicate() const;
+
+  // Returns the condition template that can be used to check if a attribute
+  // satisfies this attribute constraint.  The template may contain "{0}" that
+  // must be substituted with an expression returning an mlir::Attribute.
+  std::string getConditionTemplate() const;
+
+  // Returns the user-readable description of the constraint.  If the
+  // description is not provided, returns an empty string.
+  StringRef getDescription() const;
+
+protected:
+  // The TableGen definition of this attribute.
+  const llvm::Record *def;
+};
+
 // Wrapper class providing helper methods for accessing MLIR Attribute defined
 // in TableGen. This class should closely reflect what is defined as class
 // `Attr` in TableGen.
-class Attribute {
+class Attribute : public AttrConstraint {
 public:
-  explicit Attribute(const llvm::Record &def);
-  explicit Attribute(const llvm::Record *def);
+  explicit Attribute(const llvm::Record *record);
   explicit Attribute(const llvm::DefInit *init);
 
   // Returns true if this attribute is a derived attribute (i.e., a subclass
@@ -85,19 +109,6 @@ public:
   // Returns the code body for derived attribute. Aborts if this is not a
   // derived attribute.
   StringRef getDerivedCodeBody() const;
-
-  // Returns the predicate that can be used to check if a attribute satisfies
-  // this attribute's constraint.
-  Pred getPredicate() const;
-
-  // Returns the template that can be used to verify that an attribute satisfies
-  // the constraints for its declared attribute type.
-  // Syntax: {0} should be replaced with the attribute.
-  std::string getConditionTemplate() const;
-
-private:
-  // The TableGen definition of this attribute.
-  const llvm::Record *def;
 };
 
 } // end namespace tblgen

mlir/lib/TableGen/Attribute.cpp

@@ -36,15 +36,38 @@ static StringRef getValueAsString(const llvm::Init *init) {
   return {};
 }
 
-tblgen::Attribute::Attribute(const llvm::Record *def) : def(def) {
-  assert(def->isSubClassOf("Attr") &&
+tblgen::AttrConstraint::AttrConstraint(const llvm::Record *record)
+    : def(record) {
+  assert(def->isSubClassOf("AttrConstraint") &&
+         "must be subclass of TableGen 'AttrConstraint' class");
+}
+
+tblgen::AttrConstraint::AttrConstraint(const llvm::DefInit *init)
+    : AttrConstraint(init->getDef()) {}
+
+tblgen::Pred tblgen::AttrConstraint::getPredicate() const {
+  auto *val = def->getValue("predicate");
+  // If no predicate is specified, then return the null predicate (which
+  // corresponds to true).
+  if (!val)
+    return Pred();
+
+  const auto *pred = dyn_cast<llvm::DefInit>(val->getValue());
+  return Pred(pred);
+}
+
+std::string tblgen::AttrConstraint::getConditionTemplate() const {
+  return getPredicate().getCondition();
+}
+
+tblgen::Attribute::Attribute(const llvm::Record *record)
+    : AttrConstraint(record) {
+  assert(record->isSubClassOf("Attr") &&
          "must be subclass of TableGen 'Attr' class");
 }
 
-tblgen::Attribute::Attribute(const llvm::Record &def) : Attribute(&def) {}
-
 tblgen::Attribute::Attribute(const llvm::DefInit *init)
-    : Attribute(*init->getDef()) {}
+    : AttrConstraint(init->getDef()) {}
 
 bool tblgen::Attribute::isDerivedAttr() const {
   return def->isSubClassOf("DerivedAttr");
@@ -103,18 +126,3 @@ StringRef tblgen::Attribute::getDerivedCodeBody() const {
   assert(isDerivedAttr() && "only derived attribute has 'body' field");
   return def->getValueAsString("body");
 }
-
-tblgen::Pred tblgen::Attribute::getPredicate() const {
-  auto *val = def->getValue("predicate");
-  // If no predicate is specified, then return the null predicate (which
-  // corresponds to true).
-  if (!val)
-    return Pred();
-
-  const auto *pred = dyn_cast<llvm::DefInit>(val->getValue());
-  return Pred(pred);
-}
-
-std::string tblgen::Attribute::getConditionTemplate() const {
-  return getPredicate().getCondition();
-}

mlir/lib/TableGen/Type.cpp

@@ -53,7 +53,7 @@ llvm::StringRef tblgen::TypeConstraint::getDescription() const {
 }
 
 tblgen::TypeConstraint::TypeConstraint(const llvm::DefInit &init)
-    : def(*init.getDef()) {}
+    : TypeConstraint(*init.getDef()) {}
 
 tblgen::Type::Type(const llvm::Record &record) : TypeConstraint(record) {
   assert(def.isSubClassOf("Type") &&

mlir/tools/mlir-tblgen/RewriterGen.cpp

@@ -208,20 +208,15 @@ void Pattern::matchOp(DagInit *tree, int depth) {
 
       // TODO(jpienaar): Verify attributes.
       if (auto *namedAttr = opArg.dyn_cast<NamedAttribute *>()) {
-        // TODO(jpienaar): move to helper class.
-        if (defInit->getDef()->isSubClassOf("mAttr")) {
-          auto pred =
-              tblgen::Pred(defInit->getDef()->getValueInit("predicate"));
-          os.indent(indent)
-              << "if (!("
-              << formatv(pred.getCondition().c_str(),
+        auto constraint = tblgen::AttrConstraint(defInit);
+        std::string condition = formatv(
+            constraint.getConditionTemplate().c_str(),
             formatv("op{0}->getAttrOfType<{1}>(\"{2}\")", depth,
-                                 namedAttr->attr.getStorageType(),
-                                 namedAttr->getName()))
+                    namedAttr->attr.getStorageType(), namedAttr->getName()));
+        os.indent(indent) << "if (!(" << condition
                           << ")) return matchFailure();\n";
       }
     }
-    }
 
   StateCapture:
     auto name = tree->getArgNameStr(i);