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

[Gil Rapaport]

================
@@ -77,6 +81,75 @@ 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();
+    MemRefType 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");
+    }
+
+    mlir::Type sizeTType = mlir::emitc::SizeTType::get(rewriter.getContext());
+    Type elementType = memrefType.getElementType();
+    mlir::emitc::CallOpaqueOp sizeofElementOp =
+        rewriter.create<mlir::emitc::CallOpaqueOp>(
+            loc, sizeTType, rewriter.getStringAttr("sizeof"),
+            mlir::ValueRange{},
+            mlir::ArrayAttr::get(rewriter.getContext(),
+                                 {mlir::TypeAttr::get(elementType)}));
+    mlir::Value sizeofElement = sizeofElementOp.getResult(0);
+
+    long val = memrefType.getShape().front();
+    IntegerAttr valAttr = rewriter.getIntegerAttr(rewriter.getIndexType(), val);
+
+    mlir::Value numElements = rewriter.create<emitc::ConstantOp>(
+        loc, rewriter.getIndexType(), valAttr);
+    mlir::Value totalSizeBytes = rewriter.create<emitc::MulOp>(
+        loc, sizeTType, sizeofElement, numElements);
+
+    emitc::CallOpaqueOp allocCall;
+    StringAttr allocFunctionName;
+    mlir::Value alignmentValue;
+    SmallVector<mlir::Value, 2> argsVec;
+    if (allocOp.getAlignment()) {
+      allocFunctionName = rewriter.getStringAttr(kAlignedAllocFunctionName);
+      alignmentValue = rewriter.create<emitc::ConstantOp>(
+          loc, sizeTType,
+          rewriter.getIntegerAttr(rewriter.getIndexType(),
+                                  allocOp.getAlignment().value_or(0)));
+      argsVec.push_back(alignmentValue);
+    } else {
+      allocFunctionName = rewriter.getStringAttr(kMallocFunctionName);
+    }
+
+    argsVec.push_back(totalSizeBytes);
+    mlir::ValueRange args(argsVec);
+
+    allocCall = rewriter.create<emitc::CallOpaqueOp>(
+        loc,
+        emitc::PointerType::get(
+            mlir::emitc::OpaqueType::get(rewriter.getContext(), "void")),
+        allocFunctionName, args);
+
+    emitc::PointerType targetPointerType = emitc::PointerType::get(elementType);
+    emitc::CastOp castOp = rewriter.create<emitc::CastOp>(
+        loc, targetPointerType, allocCall.getResult(0));
+
+    rewriter.replaceOp(allocOp, castOp);
+    return success();
+  }
+  static constexpr const char *kAlignedAllocFunctionName = "aligned_alloc";
+  static constexpr const char *kMallocFunctionName = "malloc";
----------------
aniragil wrote:

[Multiple occurrences] The `k` prefix is not LLVM coding style.

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