[mlir:PDL] Expand how native constraint/rewrite functions can be defined

This commit refactors the expected form of native constraint and rewrite
functions, and greatly reduces the necessary user complexity required when
defining a native function. Namely, this commit adds in automatic processing
of the necessary PDLValue glue code, and allows for users to define
constraint/rewrite functions using the C++ types that they actually want to
use.

As an example, lets see a simple example rewrite defined today:

```
static void rewriteFn(PatternRewriter &rewriter, PDLResultList &results,
                      ArrayRef<PDLValue> args) {
  ValueRange operandValues = args[0].cast<ValueRange>();
  TypeRange typeValues = args[1].cast<TypeRange>();
  ...
  // Create an operation at some point and pass it back to PDL.
  Operation *op = rewriter.create<SomeOp>(...);
  results.push_back(op);
}
```

After this commit, that same rewrite could be defined as:

```
static Operation *rewriteFn(PatternRewriter &rewriter ValueRange operandValues,
                            TypeRange typeValues) {
  ...
  // Create an operation at some point and pass it back to PDL.
  return rewriter.create<SomeOp>(...);
}
```

Differential Revision: https://reviews.llvm.org/D122086

1 files changed, 2 insertions, 2 deletions

diff --git a/mlir/lib/Rewrite/ByteCode.cpp b/mlir/lib/Rewrite/ByteCode.cpp
index 367f51a..c2dc41a 100644
--- a/mlir/lib/Rewrite/ByteCode.cpp
+++ b/mlir/lib/Rewrite/ByteCode.cpp
@@ -1340,7 +1340,7 @@ void ByteCodeExecutor::executeApplyConstraint(PatternRewriter &rewriter) {
   });
 
   // Invoke the constraint and jump to the proper destination.
-  selectJump(succeeded(constraintFn(args, rewriter)));
+  selectJump(succeeded(constraintFn(rewriter, args)));
 }
 
 void ByteCodeExecutor::executeApplyRewrite(PatternRewriter &rewriter) {
@@ -1357,7 +1357,7 @@ void ByteCodeExecutor::executeApplyRewrite(PatternRewriter &rewriter) {
   // Execute the rewrite function.
   ByteCodeField numResults = read();
   ByteCodeRewriteResultList results(numResults);
-  rewriteFn(args, rewriter, results);
+  rewriteFn(rewriter, results, args);
 
   assert(results.getResults().size() == numResults &&
          "native PDL rewrite function returned unexpected number of results");