[Mlir-commits] [mlir] [mlir][EmitC]Expand the MemRefToEmitC pass - Lowering `AllocOp` (PR #148257)

[Jaden Angella]

================
@@ -77,6 +79,101 @@ struct ConvertAlloca final : public OpConversionPattern<memref::AllocaOp> {
   }
 };
 
+struct ConvertAlloc final : public OpConversionPattern<memref::AllocOp> {
+  using OpConversionPattern::OpConversionPattern;
+  LogicalResult
+  matchAndRewrite(memref::AllocOp allocOp, OpAdaptor operands,
+                  ConversionPatternRewriter &rewriter) const override {
+    mlir::Location loc = allocOp.getLoc();
+    auto memrefType = allocOp.getType();
+    if (!memrefType.hasStaticShape()) {
+      // TODO: Handle Dynamic shapes in the future. If the size
+      // of the allocation is the result of some function, we could
+      // potentially evaluate the function and use the result in the call to
+      // allocate.
+      return rewriter.notifyMatchFailure(
+          loc, "cannot transform alloc with dynamic shape");
+    }
+
+    Type elementType = memrefType.getElementType();
+    mlir::emitc::CallOpaqueOp sizeofElementOp =
+        rewriter.create<mlir::emitc::CallOpaqueOp>(
+            loc, mlir::emitc::SizeTType::get(rewriter.getContext()),
+            rewriter.getStringAttr("sizeof"), mlir::ValueRange{},
+            mlir::ArrayAttr::get(rewriter.getContext(),
+                                 {mlir::TypeAttr::get(elementType)}));
+    mlir::Value sizeofElement = sizeofElementOp.getResult(0);
+
+    unsigned int elementWidth = elementType.getIntOrFloatBitWidth();
+    auto indexAttr = rewriter.getIndexAttr(elementWidth);
+
+    mlir::Value numElements;
+    numElements = rewriter.create<emitc::ConstantOp>(
+        loc, rewriter.getIndexType(), indexAttr);
+    mlir::Value totalSizeBytes = rewriter.create<emitc::MulOp>(
+        loc, mlir::emitc::SizeTType::get(rewriter.getContext()), sizeofElement,
+        numElements);
+
+    auto mallocCall = rewriter.create<emitc::CallOpaqueOp>(
+        loc,
+        emitc::PointerType::get(
+            mlir::emitc::OpaqueType::get(rewriter.getContext(), "void")),
+        rewriter.getStringAttr("malloc"), mlir::ValueRange{totalSizeBytes});
+    auto targetPointerType = emitc::PointerType::get(elementType);
+    auto castOp = rewriter.create<emitc::CastOp>(loc, targetPointerType,
+                                                 mallocCall.getResult(0));
+
+    rewriter.replaceOp(allocOp, castOp);
+    return success();
+  }
+
+private:
+  std::string getCTypeName(mlir::Type type) const {
----------------
Jaddyen wrote:

Yeap! Thanks for pointing this out!

https://github.com/llvm/llvm-project/pull/148257