enhance(compiler): JitCompilerEngine: Add support for arbitrary int result tensors

Add support for result tensors composed of uint8_t, uint16_t, uint32_t
and uint64_t elements, replacing the current implementation, which
only supports uint64_t tensors.

compiler/include/zamalang/Support/JitCompilerEngine.h

@@ -32,18 +32,15 @@ inline llvm::Expected<uint64_t> typedResult(JITLambda::Argument &arguments) {
   return res;
 }
 
-// Specialization of `typedResult()` for vector results, initializing
-// an `std::vector` of the right size with the results and forwarding
-// it to the caller with move semantics.
-template <>
-inline llvm::Expected<std::vector<uint64_t>>
-typedResult(JITLambda::Argument &arguments) {
+template <typename T>
+inline llvm::Expected<std::vector<T>>
+typedVectorResult(JITLambda::Argument &arguments) {
   llvm::Expected<size_t> n = arguments.getResultVectorSize(0);
 
   if (auto err = n.takeError())
     return std::move(err);
 
-  std::vector<uint64_t> res(*n);
+  std::vector<T> res(*n);
 
   if (auto err = arguments.getResult(0, res.data(), res.size()))
     return StreamStringError() << "Cannot retrieve result:" << err;
@@ -51,6 +48,54 @@ typedResult(JITLambda::Argument &arguments) {
   return std::move(res);
 }
 
+// Specializations of `typedResult()` for vector results, initializing
+// an `std::vector` of the right size with the results and forwarding
+// it to the caller with move semantics.
+//
+// Cannot factor out into a template template <typename T> inline
+// llvm::Expected<std::vector<uint8_t>>
+// typedResult(JITLambda::Argument &arguments); due to ambiguity with
+// scalar template
+template <>
+inline llvm::Expected<std::vector<uint8_t>>
+typedResult(JITLambda::Argument &arguments) {
+  return std::move(typedVectorResult<uint8_t>(arguments));
+}
+template <>
+inline llvm::Expected<std::vector<uint16_t>>
+typedResult(JITLambda::Argument &arguments) {
+  return std::move(typedVectorResult<uint16_t>(arguments));
+}
+template <>
+inline llvm::Expected<std::vector<uint32_t>>
+typedResult(JITLambda::Argument &arguments) {
+  return std::move(typedVectorResult<uint32_t>(arguments));
+}
+template <>
+inline llvm::Expected<std::vector<uint64_t>>
+typedResult(JITLambda::Argument &arguments) {
+  return std::move(typedVectorResult<uint64_t>(arguments));
+}
+
+template <typename T>
+llvm::Expected<std::unique_ptr<LambdaArgument>>
+buildTensorLambdaResult(JITLambda::Argument &arguments) {
+  llvm::Expected<std::vector<T>> tensorOrError =
+      typedResult<std::vector<T>>(arguments);
+
+  if (!tensorOrError)
+    return std::move(tensorOrError.takeError());
+
+  llvm::Expected<std::vector<int64_t>> tensorDimOrError =
+      arguments.getResultDimensions(0);
+
+  if (!tensorDimOrError)
+    return std::move(tensorDimOrError.takeError());
+
+  return std::move(std::make_unique<TensorLambdaArgument<IntLambdaArgument<T>>>(
+      *tensorOrError, *tensorDimOrError));
+}
+
 // Specialization of `typedResult()` for a single result wrapped into
 // a `LambdaArgument`.
 template <>
@@ -73,25 +118,26 @@ typedResult(JITLambda::Argument &arguments) {
   }
 
   case JITLambda::Argument::ResultType::TENSOR: {
-    llvm::Expected<std::vector<uint64_t>> tensorOrError =
-        typedResult<std::vector<uint64_t>>(arguments);
+    llvm::Expected<size_t> width = arguments.getResultWidth(0);
 
-    if (!tensorOrError)
-      return std::move(tensorOrError.takeError());
+    if (!width)
+      return std::move(width.takeError());
 
-    llvm::Expected<std::vector<int64_t>> tensorDimOrError =
-        arguments.getResultDimensions(0);
-    if (!tensorDimOrError)
-      return std::move(tensorDimOrError.takeError());
-
-    return std::move(
-        std::make_unique<TensorLambdaArgument<IntLambdaArgument<uint64_t>>>(
-            *tensorOrError, *tensorDimOrError));
+    if (*width > 64)
+      return StreamStringError("Cannot handle scalars with more than 64 bits");
+    if (*width > 32)
+      return buildTensorLambdaResult<uint64_t>(arguments);
+    else if (*width > 16)
+      return buildTensorLambdaResult<uint32_t>(arguments);
+    else if (*width > 8)
+      return buildTensorLambdaResult<uint16_t>(arguments);
+    else if (*width <= 8)
+      return buildTensorLambdaResult<uint8_t>(arguments);
   }
   }
 
   return StreamStringError("Unknown result type");
-}
+} // namespace
 
 // Adaptor class that adds arguments specified as instances of
 // `LambdaArgument` to `JitLambda::Argument`.