Less pointer indirection for TFE_OpAttrs, add TFE_OpGetAttrs

We'll want this for implementing copy for `TF_AbstractOp`s backed by `TFE_Op`s (since we want to copy the type/attributes but not the inputs).

PiperOrigin-RevId: 309756974
Change-Id: I07a8c48f50ab6d3c8a7d7db972fb60202b86434d

tensorflow/c/BUILD

@@ -58,6 +58,7 @@ filegroup(
     name = "pywrap_required_hdrs",
     srcs = [
         "c_api_internal.h",
+        "conversion_macros.h",
         "python_api.h",
         "tensor_interface.h",
         "tf_status_helper.h",

tensorflow/c/conversion_macros.h

@@ -25,6 +25,9 @@ limitations under the License.
     return reinterpret_cast<const cpp_impl *>(w);                              \
   }                                                                            \
                                                                                \
-  inline wrapper *wrap(cpp_impl *i) { return reinterpret_cast<wrapper *>(i); }
+  inline wrapper *wrap(cpp_impl *i) { return reinterpret_cast<wrapper *>(i); } \
+  inline const wrapper *wrap(const cpp_impl *i) {                              \
+    return reinterpret_cast<const wrapper *>(i);                               \
+  }
 
 #endif  // TENSORFLOW_C_CONVERSION_MACROS_H_

tensorflow/c/eager/BUILD

@@ -247,6 +247,7 @@ cc_library(
         "//tensorflow:internal",
     ],
     deps = [
+        "//tensorflow/c:conversion_macros",
         "//tensorflow/c:tf_status",
         "//tensorflow/core:protos_all_cc",
         "//tensorflow/core/common_runtime/eager:attr_builder",

tensorflow/c/eager/c_api.cc

@@ -1483,9 +1483,14 @@ void TFE_ContextEndStep(TFE_Context* ctx) {
   context->EndStep();
 }
 
+const TFE_OpAttrs* TFE_OpGetAttrs(TFE_Op* op) {
+  return tensorflow::wrap(
+      &OperationFromInterface(tensorflow::unwrap(op))->Attrs());
+}
+
 void TFE_OpAddAttrs(TFE_Op* op, const TFE_OpAttrs* attrs) {
   tensorflow::AttrValueMap m;
-  attrs->attributes->FillAttrValueMap(&m);
+  tensorflow::unwrap(attrs)->FillAttrValueMap(&m);
   tensorflow::EagerOperation* operation =
       OperationFromInterface(tensorflow::unwrap(op));
   tensorflow::AttrBuilder* destination = operation->MutableAttrs();
@@ -1497,8 +1502,8 @@ void TFE_OpAddAttrs(TFE_Op* op, const TFE_OpAttrs* attrs) {
 void TFE_OpAttrsSerialize(const TFE_OpAttrs* attrs, TF_Buffer* buf,
                           TF_Status* status) {
   tensorflow::NameAttrList name_and_attrs;
-  attrs->attributes->FillAttrValueMap(name_and_attrs.mutable_attr());
+  tensorflow::unwrap(attrs)->FillAttrValueMap(name_and_attrs.mutable_attr());
-  name_and_attrs.set_name(attrs->attributes->op_name());
+  name_and_attrs.set_name(tensorflow::unwrap(attrs)->op_name());
   status->status = MessageToBuffer(name_and_attrs, buf);
 }
 
@@ -1619,9 +1624,9 @@ class CustomDeviceAPI : public tensorflow::CustomDevice {
     }
     std::vector<TFE_TensorHandle*> outputs(*num_retvals);
     TF_Status status;
-    TFE_OpAttrs attributes(&op->Attrs());
     device_.execute(context_, inputs.size(), inputs.data(), op->Name().c_str(),
-                    &attributes, num_retvals, outputs.data(), &status, info_);
+                    wrap(&op->Attrs()), num_retvals, outputs.data(), &status,
+                    info_);
     if (status.status.ok()) {
       for (int i = 0; i < *num_retvals; ++i) {
         retvals[i] = tensorflow::TensorHandleFromInterface(

tensorflow/c/eager/c_api_experimental.h

@@ -431,6 +431,9 @@ TF_CAPI_EXPORT extern void TFE_HostAddressSpace(TFE_Context* ctx,
 // A reference to an op's name -> attribute mapping
 typedef struct TFE_OpAttrs TFE_OpAttrs;
 
+// Fetch a reference to `op`'s attributes. The returned reference is only valid
+// while `op` is alive.
+const TFE_OpAttrs* TFE_OpGetAttrs(TFE_Op* op);
 // Add attributes in `attrs` to `op`.
 //
 // Does not overwrite or update existing attributes, but adds new ones.

tensorflow/c/eager/c_api_test.cc

@@ -1591,15 +1591,11 @@ TEST(CAPI, TestTFE_OpAddAttrs) {
   TFE_Op* var_op = TFE_NewOp(ctx, "VarHandleOp", status);
   TFE_OpSetAttrType(var_op, "dtype", TF_INT64);
   TFE_OpSetAttrShape(var_op, "shape", {}, 0, status);
-  // There is currently no API to fetch attributes from an operation, fetching
+  const TFE_OpAttrs* attributes = TFE_OpGetAttrs(var_op);
-  // happens only as an implementation detail of custom devices.
-  tensorflow::EagerOperation* operation =
-      OperationFromInterface(tensorflow::unwrap(var_op));
-  TFE_OpAttrs attributes{&operation->Attrs()};
 
   TFE_Op* copy_op = TFE_NewOp(ctx, "VarHandleOp", status);
   TFE_OpSetAttrType(copy_op, "dtype", TF_FLOAT);
-  TFE_OpAddAttrs(copy_op, &attributes);
+  TFE_OpAddAttrs(copy_op, attributes);
   unsigned char is_list = 0;
   ASSERT_EQ(TF_ATTR_TYPE,
             TFE_OpGetAttrType(copy_op, "dtype", &is_list, status));
@@ -1631,14 +1627,10 @@ TEST(CAPI, TestTFE_OpAttrsSerialize) {
   CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
   TFE_OpSetAttrType(var_op, "dtype", TF_INT64);
   TFE_OpSetAttrShape(var_op, "shape", {}, 0, status);
-  // There is currently no API to fetch attributes from an operation, fetching
+  const TFE_OpAttrs* attributes = TFE_OpGetAttrs(var_op);
-  // happens only as an implementation detail of custom devices.
-  tensorflow::EagerOperation* operation =
-      OperationFromInterface(tensorflow::unwrap(var_op));
-  TFE_OpAttrs attributes{&operation->Attrs()};
 
   TF_Buffer* serialized_attr_values = TF_NewBuffer();
-  TFE_OpAttrsSerialize(&attributes, serialized_attr_values, status);
+  TFE_OpAttrsSerialize(attributes, serialized_attr_values, status);
   CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
   tensorflow::NameAttrList name_and_attrs;
   ASSERT_TRUE(name_and_attrs.ParseFromArray(serialized_attr_values->data,

tensorflow/c/eager/tfe_op_attrs_internal.h

@@ -15,33 +15,21 @@ limitations under the License.
 #ifndef TENSORFLOW_C_EAGER_TFE_OP_ATTRS_INTERNAL_H_
 #define TENSORFLOW_C_EAGER_TFE_OP_ATTRS_INTERNAL_H_
 
-#include <algorithm>
+#include "tensorflow/c/conversion_macros.h"
-#include <cstddef>
-#include <map>
-#include <memory>
-#include <queue>
-#include <string>
-#include <vector>
-
 #include "tensorflow/c/tf_status.h"
 #include "tensorflow/core/common_runtime/eager/attr_builder.h"
 #include "tensorflow/core/framework/attr_value.pb.h"
 
 // An equivalent of a tensorflow::NameAttrList protocol buffer, but used in ways
 // that sometimes do not require serialization.
+typedef struct TFE_OpAttrs TFE_OpAttrs;
+
 typedef struct TFE_Context TFE_Context;
 typedef struct TFE_Op TFE_Op;
 
-struct TFE_OpAttrs {
-  explicit TFE_OpAttrs() : attributes(nullptr) {}
-
-  explicit TFE_OpAttrs(const tensorflow::AttrBuilder* value)
-      : attributes(value) {}
-
-  const tensorflow::AttrBuilder* attributes;
-};
-
 namespace tensorflow {
+DEFINE_CONVERSION_FUNCTIONS(tensorflow::AttrBuilder, TFE_OpAttrs);
+
 // Set an AttrValue on the op. Doesn't handle the list types.
 void SetOpAttrValueScalar(TFE_Context* ctx, TFE_Op* op,
                           const tensorflow::AttrValue& default_value,