[llvm] [mlir] [mlir][core] Add an MLIR "pattern catalog" generator (PR #146228)

[Jeremy Kun via llvm-commits]

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@@ -206,14 +227,38 @@ LogicalResult PatternApplicator::matchAndRewrite(
           } else {
             LLVM_DEBUG(llvm::dbgs() << "Trying to match \""
                                     << bestPattern->getDebugName() << "\"\n");
-
             const auto *pattern =
                 static_cast<const RewritePattern *>(bestPattern);
-            result = pattern->matchAndRewrite(op, rewriter);
 
+#ifdef MLIR_ENABLE_CATALOG_GENERATOR
+            OpBuilder::Listener *oldListener = rewriter.getListener();
+            int status;
+            const char *mangledPatternName = typeid(*pattern).name();
+            char *demangled = abi::__cxa_demangle(mangledPatternName, nullptr,
+                                                  nullptr, &status);
+            std::string demangledPatternName;
+            if (status == 0 && demangled) {
+              demangledPatternName = demangled;
+              free(demangled);
+            } else {
+              // Fallback in case demangling fails.
+              demangledPatternName = mangledPatternName;
+            }
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j2kun wrote:

It looks like the demangling differences are pretty significant in the two implementations. For example, RTTI can get this one:

`:mlir::RewritePatternSet::add<mlir::acc::AtomicUpdateOp>(llvm::LogicalResult (*)(mlir::acc::AtomicUpdateOp, mlir::PatternRewriter&), mlir::PatternBenefit, llvm::ArrayRef<llvm::StringRef>)::FnPattern | notifyOperationErased | acc.atomic.update`

But that corresponds to an empty debugName. I _think_ this corresponds to canonicalization patterns that are automatically added during mlir-tablegen via [this code path](https://github.com/llvm/llvm-project/blob/68d83fae70b2fa136b6c4a8c91af9e615eeedf95/mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp#L3548-L3560)

https://github.com/llvm/llvm-project/pull/146228