chore: import upstream snapshot with attribution

third_party/tf_runtime/f16_attr.patch

@@ -0,0 +1,21 @@
+diff --git a/include/tfrt/basic_kernels/opdefs/basic_kernels.td b/include/tfrt/basic_kernels/opdefs/basic_kernels.td
+index 80dacbf2..b42004a9 100644
+--- a/include/tfrt/basic_kernels/opdefs/basic_kernels.td
++++ b/include/tfrt/basic_kernels/opdefs/basic_kernels.td
+@@ -85,16 +85,6 @@ class ConstantOp<string suffix, Type baseType, Attr attr>
+   let hasVerifier = 0;
+ }
+ 
+-// MLIR's OpBase.td defines F32Attr and F64Attr, but no F16Attr or BF16Attr
+-def F16Attr : FloatAttrBase<F16, "16-bit float attribute">;
+-def BF16Attr : TypedAttrBase<
+-  BF16, "FloatAttr",
+-  And<[CPred<"llvm::isa<::mlir::FloatAttr>($_self)">,
+-       CPred<"llvm::cast<::mlir::FloatAttr>($_self).getType().isBF16()">]>,
+-  "bfloat16 attribute"> {
+-  let returnType = [{ ::llvm::APFloat }];
+-}
+-
+ def ConstantI1Op  : ConstantOp<"i1", I1, I1Attr>;
+ def ConstantI32Op : ConstantOp<"i32", I32, I32Attr>;
+ def ConstantI64Op : ConstantOp<"i64", I64, I64Attr>;

third_party/tf_runtime/workspace.bzl

@@ -0,0 +1,20 @@
+"""Provides the repository macro to import TFRT."""
+
+load("//third_party:repo.bzl", "tf_http_archive", "tf_mirror_urls")
+
+def repo():
+    """Imports TFRT."""
+
+    # Attention: tools parse and update these lines.
+    TFRT_COMMIT = "4ecc3a44a32c832b748328bed3f9a599f795ca8d"
+    TFRT_SHA256 = "5e81d70f9534340f7ef8e63ec43bdd5971135e48183079be50ecb3f74b1fed66"
+
+    tf_http_archive(
+        name = "tf_runtime",
+        sha256 = TFRT_SHA256,
+        strip_prefix = "runtime-{commit}".format(commit = TFRT_COMMIT),
+        urls = tf_mirror_urls("https://github.com/tensorflow/runtime/archive/{commit}.tar.gz".format(commit = TFRT_COMMIT)),
+        # A patch file can be provided for atomic commits to both TF and TFRT.
+        # The job that bumps the TFRT_COMMIT also resets patch_file to 'None'.
+        patch_file = ["//third_party/tf_runtime:f16_attr.patch"],
+    )