PDLL: Allow to define builtin native calls

mlir/include/mlir/Dialect/PDL/IR/Builtins.h

@@ -0,0 +1,36 @@
+//===- Builtins.h - Builtin functions of the PDL dialect --------*- 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 builtin functions of the PDL dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_PDL_IR_BUILTINS_H_
+#define MLIR_DIALECT_PDL_IR_BUILTINS_H_
+
+namespace mlir {
+class PDLPatternModule;
+class Attribute;
+class PatternRewriter;
+
+namespace pdl {
+void registerBuiltins(PDLPatternModule &pdlPattern);
+
+namespace builtin {
+Attribute createDictionaryAttr(PatternRewriter &rewriter);
+Attribute addEntryToDictionaryAttr(PatternRewriter &rewriter,
+                                   Attribute dictAttr, Attribute attrName,
+                                   Attribute attrEntry);
+Attribute createArrayAttr(PatternRewriter &rewriter);
+Attribute addElemToArrayAttr(PatternRewriter &rewriter, Attribute attr,
+                             Attribute element);
+} // namespace builtin
+} // namespace pdl
+} // namespace mlir
+
+#endif // MLIR_DIALECT_PDL_IR_BUILTINS_H_

mlir/lib/Dialect/PDL/IR/Builtins.cpp

@@ -0,0 +1,56 @@
+#include <mlir/Dialect/PDL/IR/Builtins.h>
+#include <mlir/IR/PatternMatch.h>
+
+using namespace mlir;
+
+namespace mlir::pdl {
+namespace builtin {
+mlir::Attribute createDictionaryAttr(mlir::PatternRewriter &rewriter) {
+  return rewriter.getDictionaryAttr({});
+}
+
+mlir::Attribute addEntryToDictionaryAttr(mlir::PatternRewriter &rewriter,
+                                         mlir::Attribute dictAttr,
+                                         mlir::Attribute attrName,
+                                         mlir::Attribute attrEntry) {
+  assert(isa<DictionaryAttr>(dictAttr));
+  auto attr = dictAttr.cast<DictionaryAttr>();
+  auto name = attrName.cast<StringAttr>();
+  std::vector<NamedAttribute> values = attr.getValue().vec();
+
+  // Remove entry if it exists in the dictionary.
+  llvm::erase_if(values, [&](NamedAttribute &namedAttr) {
+    return namedAttr.getName() == name.getValue();
+  });
+
+  values.push_back(rewriter.getNamedAttr(name, attrEntry));
+  return rewriter.getDictionaryAttr(values);
+}
+
+mlir::Attribute createArrayAttr(mlir::PatternRewriter &rewriter) {
+  return rewriter.getArrayAttr({});
+}
+
+mlir::Attribute addElemToArrayAttr(mlir::PatternRewriter &rewriter,
+                                   mlir::Attribute attr,
+                                   mlir::Attribute element) {
+  assert(isa<ArrayAttr>(attr));
+  auto values = cast<ArrayAttr>(attr).getValue().vec();
+  values.push_back(element);
+  return rewriter.getArrayAttr(values);
+}
+} // namespace builtin
+
+void registerBuiltins(PDLPatternModule &pdlPattern) {
+  using namespace builtin;
+  // See Parser::defineBuiltins()
+  pdlPattern.registerRewriteFunction("__builtin_createDictionaryAttr",
+                                     createDictionaryAttr);
+  pdlPattern.registerRewriteFunction("__builtin_addEntryToDictionaryAttr",
+                                     addEntryToDictionaryAttr);
+  pdlPattern.registerRewriteFunction("__builtin_createArrayAttr",
+                                     createArrayAttr);
+  pdlPattern.registerRewriteFunction("__builtin_addElemToArrayAttr",
+                                     addElemToArrayAttr);
+}
+} // namespace mlir::pdl

mlir/lib/Dialect/PDL/IR/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_mlir_dialect_library(MLIRPDLDialect
+  Builtins.cpp
   PDL.cpp
   PDLTypes.cpp
 

mlir/lib/Rewrite/FrozenRewritePatternSet.cpp

@@ -13,6 +13,7 @@
 #include "mlir/Interfaces/SideEffectInterfaces.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassManager.h"
+#include <mlir/Dialect/PDL/IR/Builtins.h>
 #include <optional>
 
 using namespace mlir;
@@ -132,6 +133,8 @@ FrozenRewritePatternSet::FrozenRewritePatternSet(
     llvm::report_fatal_error(
         "failed to lower PDL pattern module to the PDL Interpreter");
 
+  pdl::registerBuiltins(pdlPatterns);
+
   // Generate the pdl bytecode.
   impl->pdlByteCode = std::make_unique<detail::PDLByteCode>(
       pdlModule, pdlPatterns.takeConfigs(), configMap,

mlir/lib/Tools/PDLL/Parser/Parser.cpp

@@ -106,6 +106,17 @@ class Parser {
   /// Pop the last decl scope from the lexer.
   void popDeclScope() { curDeclScope = curDeclScope->getParentScope(); }
 
+  /// Creates a native constraint taking a set of Attr as arguments.
+  /// The number of arguments and their names is given by argNames.
+  /// The native returns an Attr when returnsAttr is true, otherwise returns
+  /// nothing.
+  template <class T>
+  T *declareBuiltin(StringRef name, ArrayRef<StringRef> argNames,
+                    bool returnsAttr);
+
+  /// Register all builtin natives.
+  void declareBuiltins();
+
   /// Parse the body of an AST module.
   LogicalResult parseModuleBody(SmallVectorImpl<ast::Decl *> &decls);
 
@@ -418,12 +429,12 @@ class Parser {
   FailureOr<ast::MemberAccessExpr *>
   createMemberAccessExpr(ast::Expr *parentExpr, StringRef name, SMRange loc);
 
-  // Create a native call with \p nativeFuncName and \p arguments.
+  // Create a native call with \p function and \p arguments.
   // This should be accompanied by a C++ implementation of the function that
   // needs to be linked and registered in passes that process PDLL files.
-  FailureOr<ast::DeclRefExpr *>
-  createNativeCall(SMRange loc, StringRef nativeFuncName,
-                   MutableArrayRef<ast::Expr *> arguments);
+  FailureOr<ast::Expr *>
+  createBuiltinCall(SMRange loc, ast::Decl *function,
+                    MutableArrayRef<ast::Expr *> arguments);
 
   /// Validate the member access `name` into the given parent expression. On
   /// success, this also returns the type of the member accessed.
@@ -578,13 +589,64 @@ class Parser {
 
   /// The optional code completion context.
   CodeCompleteContext *codeCompleteContext;
+
+  struct {
+    ast::UserRewriteDecl *createDictionaryAttr;
+    ast::UserRewriteDecl *addEntryToDictionaryAttr;
+    ast::UserRewriteDecl *createArrayAttr;
+    ast::UserRewriteDecl *addElemToArrayAttr;
+  } builtins{};
 };
 } // namespace
 
+template <class T>
+T *Parser::declareBuiltin(StringRef name, ArrayRef<StringRef> argNames,
+                          bool returnsAttr) {
+  SMRange loc;
+  auto attrConstr = ast::ConstraintRef(
+      ast::AttrConstraintDecl::create(ctx, loc, nullptr), loc);
+
+  pushDeclScope();
+  SmallVector<ast::VariableDecl *> args;
+  for (auto argName : argNames) {
+    FailureOr<ast::VariableDecl *> arg =
+        createArgOrResultVariableDecl(argName, loc, attrConstr);
+    assert(succeeded(arg));
+    args.push_back(*arg);
+  }
+  SmallVector<ast::VariableDecl *> results;
+  if (returnsAttr) {
+    auto result = createArgOrResultVariableDecl("", loc, attrConstr);
+    assert(succeeded(result));
+    results.push_back(*result);
+  }
+  popDeclScope();
+
+  auto *constraintDecl = T::createNative(ctx, ast::Name::create(ctx, name, loc),
+                                         args, results, {}, attrTy);
+  curDeclScope->add(constraintDecl);
+  return constraintDecl;
+}
+
+void Parser::declareBuiltins() {
+  builtins.createDictionaryAttr = declareBuiltin<ast::UserRewriteDecl>(
+      "__builtin_createDictionaryAttr", {}, /*returnsAttr=*/true);
+  builtins.addEntryToDictionaryAttr = declareBuiltin<ast::UserRewriteDecl>(
+      "__builtin_addEntryToDictionaryAttr", {"attr", "attrName", "attrEntry"},
+      /*returnsAttr=*/true);
+  builtins.createArrayAttr = declareBuiltin<ast::UserRewriteDecl>(
+      "__builtin_createArrayAttr", {}, /*returnsAttr=*/true);
+  builtins.addElemToArrayAttr = declareBuiltin<ast::UserRewriteDecl>(
+      "__builtin_addElemToArrayAttr", {"attr", "element"},
+      /*returnsAttr=*/true);
+}
+
 FailureOr<ast::Module *> Parser::parseModule() {
   SMLoc moduleLoc = curToken.getStartLoc();
   pushDeclScope();
 
+  declareBuiltins();
+
   // Parse the top-level decls of the module.
   SmallVector<ast::Decl *> decls;
   if (failed(parseModuleBody(decls)))
@@ -1874,7 +1936,7 @@ FailureOr<ast::Expr *> Parser::parseArrayAttrExpr() {
         "Parsing of array attributes as constraint not supported!");
 
   auto arrayAttrCall =
-      createNativeCall(curToken.getLoc(), "createArrayAttr", {});
+      createBuiltinCall(curToken.getLoc(), builtins.createArrayAttr, {});
   if (failed(arrayAttrCall))
     return failure();
 
@@ -1884,8 +1946,8 @@ FailureOr<ast::Expr *> Parser::parseArrayAttrExpr() {
       return failure();
 
     SmallVector<ast::Expr *> arrayAttrArgs{*arrayAttrCall, *attr};
-    auto elemToArrayCall = createNativeCall(
-        curToken.getLoc(), "addElemToArrayAttr", arrayAttrArgs);
+    auto elemToArrayCall = createBuiltinCall(
+        curToken.getLoc(), builtins.addElemToArrayAttr, arrayAttrArgs);
     if (failed(elemToArrayCall))
       return failure();
 
@@ -1966,7 +2028,7 @@ FailureOr<ast::Expr *> Parser::parseDictAttrExpr() {
     return emitError(
         "Parsing of dictionary attributes as constraint not supported!");
 
-  auto dictAttrCall = createNativeCall(loc, "createDictionaryAttr", {});
+  auto dictAttrCall = createBuiltinCall(loc, builtins.createDictionaryAttr, {});
   if (failed(dictAttrCall))
     return failure();
 
@@ -2000,8 +2062,8 @@ FailureOr<ast::Expr *> Parser::parseDictAttrExpr() {
     // Create addEntryToDictionaryAttr native call.
     SmallVector<ast::Expr *> arrayAttrArgs{*dictAttrCall, *stringAttrRef,
                                            namedDecl->getValue()};
-    auto entryToDictionaryCall =
-        createNativeCall(loc, "addEntryToDictionaryAttr", arrayAttrArgs);
+    auto entryToDictionaryCall = createBuiltinCall(
+        loc, builtins.addEntryToDictionaryAttr, arrayAttrArgs);
     if (failed(entryToDictionaryCall))
       return failure();
 
@@ -2923,33 +2985,20 @@ Parser::createMemberAccessExpr(ast::Expr *parentExpr, StringRef name,
   return ast::MemberAccessExpr::create(ctx, loc, parentExpr, name, *memberType);
 }
 
-FailureOr<ast::DeclRefExpr *>
-Parser::createNativeCall(SMRange loc, StringRef nativeFuncName,
-                         MutableArrayRef<ast::Expr *> arguments) {
+FailureOr<ast::Expr *>
+Parser::createBuiltinCall(SMRange loc, ast::Decl *function,
+                          MutableArrayRef<ast::Expr *> arguments) {
 
-  FailureOr<ast::Expr *> nativeFuncExpr = parseDeclRefExpr(nativeFuncName, loc);
+  FailureOr<ast::Expr *> nativeFuncExpr = createDeclRefExpr(loc, function);
   if (failed(nativeFuncExpr))
     return failure();
 
-  if (!(*nativeFuncExpr)->getType().isa<ast::RewriteType>())
-    return emitError(nativeFuncName + " should be defined as a rewriter.");
-
   FailureOr<ast::CallExpr *> nativeCall =
       createCallExpr(loc, *nativeFuncExpr, arguments);
   if (failed(nativeCall))
     return failure();
 
-  // Create a unique anonymous name declaration to use, as its name is not
-  // important.
-  std::string anonName =
-      llvm::formatv("{0}_{1}", nativeFuncName, anonymousDeclNameCounter++)
-          .str();
-  FailureOr<ast::VariableDecl *> varDecl = defineVariableDecl(
-      anonName, loc, (*nativeCall)->getType(), *nativeCall, {});
-  if (failed(varDecl))
-    return failure();
-
-  return createDeclRefExpr(loc, *varDecl);
+  return *nativeCall;
 }
 
 FailureOr<ast::Type> Parser::validateMemberAccess(ast::Expr *parentExpr,