[Mlir-commits] [mlir] [MLIR][Python] Support Python-defined rewrite patterns (PR #162699)

[llvmlistbot at llvm.org]

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@@ -165,13 +175,116 @@ class PyFrozenRewritePatternSet {
   MlirFrozenRewritePatternSet set;
 };
 
+class PyRewritePatternSet {
+public:
+  PyRewritePatternSet(MlirContext ctx)
+      : set(mlirRewritePatternSetCreate(ctx)), ctx(ctx) {}
+  ~PyRewritePatternSet() {
+    if (set.ptr)
+      mlirRewritePatternSetDestroy(set);
+  }
+
+  void add(MlirStringRef rootName, unsigned benefit,
+           const nb::callable &matchAndRewrite) {
+    MlirRewritePatternCallbacks callbacks;
+    callbacks.construct = [](void *userData) {
+      nb::handle(static_cast<PyObject *>(userData)).inc_ref();
+    };
+    callbacks.destruct = [](void *userData) {
+      nb::handle(static_cast<PyObject *>(userData)).dec_ref();
+    };
+    callbacks.matchAndRewrite = [](MlirRewritePattern pattern, MlirOperation op,
+                                   MlirPatternRewriter rewriter,
+                                   void *userData) -> MlirLogicalResult {
+      nb::handle f(static_cast<PyObject *>(userData));
+      nb::object res = f(op, PyPatternRewriter(rewriter), pattern);
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PragmaTwice wrote:

Currently it is useless. There is no attribute/method defined inside `pattern` so we cannot use it in Python. I just thought that, if in the future we add some method to make it useful, we don't need to add a new argument to the callback to break users' code.  So it is to mainly avoid breaking changes. And yeah I also don't know if there is some case that these Pattern APIs are necessary. 🤣 

https://github.com/llvm/llvm-project/pull/162699