[mlir][tosa] Support DenseResourceElementsAttr in TOSA transpose folders (#124532)

Handle dense resource attributes in the transpose TOSA folder.
Currently their interface does not align with the rest of the
`ElementsAttr` when it comes to data accessing hence the special
handling.

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>

mlir/lib/Dialect/Tosa/Transforms/TosaFolders.cpp

@@ -18,6 +18,7 @@
 #include "mlir/Dialect/Utils/IndexingUtils.h"
 #include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/BuiltinTypes.h"
+#include "mlir/IR/DialectResourceBlobManager.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/Pass/Pass.h"
 #include "llvm/ADT/APFloat.h"
@@ -176,6 +177,28 @@ DenseElementsAttr transposeType(const RangeType &data, ShapedType inputType,
                                 llvm::ArrayRef<ElementType>(outputValues));
 }
 
+// Try to get the values of a DenseResourceElementsAttr construct
+template <typename T>
+std::optional<ArrayRef<T>> tryGetDenseResourceValues(ElementsAttr attr) {
+  if (auto denseResource = dyn_cast<DenseResourceElementsAttr>(attr)) {
+    // Check that the resource memory blob exists
+    AsmResourceBlob *blob = denseResource.getRawHandle().getBlob();
+    if (!blob)
+      return std::nullopt;
+
+    // Check that the data are in a valid form
+    bool isSplat = false;
+    if (!DenseElementsAttr::isValidRawBuffer(attr.getShapedType(),
+                                             blob->getData(), isSplat)) {
+      return std::nullopt;
+    }
+
+    return blob->template getDataAs<T>();
+  }
+
+  return std::nullopt;
+}
+
 // A type specialized transposition of an ElementsAttr.
 // This implementation tries to operate on the underlying data in its raw
 // representation when possible to avoid allocating a large number of Attribute
@@ -183,6 +206,7 @@ DenseElementsAttr transposeType(const RangeType &data, ShapedType inputType,
 DenseElementsAttr transpose(ElementsAttr attr, ShapedType inputType,
                             ShapedType outputType,
                             llvm::ArrayRef<int64_t> permValues) {
+  // Handle generic ElementsAttr
   if (auto data = attr.tryGetValues<bool>())
     return transposeType(*data, inputType, outputType, permValues);
 
@@ -204,6 +228,35 @@ DenseElementsAttr transpose(ElementsAttr attr, ShapedType inputType,
   if (auto data = attr.tryGetValues<APFloat>())
     return transposeType(*data, inputType, outputType, permValues);
 
+  // Handle DenseResourceElementsAttr
+  if (isa<DenseResourceElementsAttr>(attr)) {
+    auto elementTy = attr.getElementType();
+
+    if (auto data = tryGetDenseResourceValues<bool>(attr);
+        data && elementTy.isInteger(1))
+      return transposeType(*data, inputType, outputType, permValues);
+
+    if (auto data = tryGetDenseResourceValues<int8_t>(attr);
+        data && elementTy.isInteger(8))
+      return transposeType(*data, inputType, outputType, permValues);
+
+    if (auto data = tryGetDenseResourceValues<int16_t>(attr);
+        data && elementTy.isInteger(16))
+      return transposeType(*data, inputType, outputType, permValues);
+
+    if (auto data = tryGetDenseResourceValues<int32_t>(attr);
+        data && elementTy.isInteger(32))
+      return transposeType(*data, inputType, outputType, permValues);
+
+    if (auto data = tryGetDenseResourceValues<int64_t>(attr);
+        data && elementTy.isInteger(64))
+      return transposeType(*data, inputType, outputType, permValues);
+
+    if (auto data = tryGetDenseResourceValues<float>(attr);
+        data && elementTy.isF32())
+      return transposeType(*data, inputType, outputType, permValues);
+  }
+
   return nullptr;
 }
 

mlir/test/Dialect/Tosa/constant-op-fold.mlir

@@ -108,18 +108,18 @@ func.func @transpose_nofold_quantized_types() -> tensor<1x1x2x2x!quant.uniform<i
   return %0: tensor<1x1x2x2x!quant.uniform<i8<-127:127>:f32:3, {1.000000e-01,1.000000e-01}>>
 }
 
-// CHECK-LABEL: @transpose_nofold_dense_resource
-func.func @transpose_nofold_dense_resource() -> tensor<2x2xf32> {
+// CHECK-LABEL: @transpose_fold_dense_resource
+func.func @transpose_fold_dense_resource() -> tensor<2x2xf32> {
   %0 = "tosa.const"() <{values = dense_resource<resource> : tensor<2x2xf32>}> : () -> tensor<2x2xf32>
 
-  // CHECK: tosa.transpose
+  // CHECK-NOT: tosa.transpose
   %2 = tosa.transpose %0 { perms = array<i32: 1, 0> }: (tensor<2x2xf32>) -> tensor<2x2xf32>
   return %2 : tensor<2x2xf32>
 }
 {-#
   dialect_resources: {
     builtin: {
-      resource: "0x08000000010000000000000002000000000000000300000000000000"
+      resource: "0x040000003f800000400000004040000040800000"
     }
   }
 #-}