1414
1515namespace torch_xla {
1616
17- // Creates a new Status instance, appending the current location (e.g. file and
18- // line information) to the status message.
17+ // If `XLA_SHOW_CPP_ERROR_CONTEXT` is set, creates a new Status instance,
18+ // appending the current location (e.g. file and line information) to the
19+ // status message.
20+ //
21+ // This should be used whenever we are returning new error status.
22+ //
23+ // Example:
24+ //
25+ // XLA_ERROR_WITH_LOCATION(
26+ // absl::InvalidArgumentError("Error message.")
27+ // );
28+ //
29+ // If `XLA_SHOW_CPP_ERROR_CONTEXT` is set, the error shown will be:
30+ //
31+ // Error message. (at <cpp-source-file>:<line>)
1932//
20- // This should be used whenever we are returning new error status, instead of
21- // propagating. Then, if `XLA_SHOW_CPP_ERROR_CONTEXT` environment variable is
22- // set, the location information will be shown.
2333#define XLA_ERROR_WITH_LOCATION (status ) \
2434 ::torch_xla::MaybeWithLocation (status, __FILE__, __LINE__)
2535
26- #define XLA_CONCAT (a, b ) XLA_CONCAT_IMPL (a, b)
27- #define XLA_CONCAT_IMPL (a, b ) a##b
36+ #define XLA_CONCAT_ (a, b ) XLA_CONCAT_IMPL_ (a, b)
37+ #define XLA_CONCAT_IMPL_ (a, b ) a##b
2838
2939// Unique identifier for the status variable for the current line.
30- #define XLA_STATUS_VAR XLA_CONCAT (status__ , __LINE__)
40+ #define XLA_STATUS_VAR_ XLA_CONCAT_ (status_ , __LINE__)
3141
3242// Provides a flexible way to handle error checking with optional message
3343// modification. It evaluates `expr`, checks if it's OK, and either:
3444// 1. Returns early with an error status (potentially modified by the provided
3545// additional messages)
3646// 2. Proceeds with the given `then` block if successful
37- #define XLA_RETURN_IF_ERROR_IMPL (expr, var, then, ...) \
47+ #define XLA_RETURN_IF_ERROR_IMPL_ (expr, var, then, ...) \
3848 auto var = (expr); \
3949 if (!var.ok()) { \
4050 return ::torch_xla::MaybeWithNewMessage ( \
4151 ::torch_xla::GetStatus (var), __FILE__, __LINE__, ##__VA_ARGS__); \
4252 } \
43- then;
53+ then
4454
4555// Propagates `rexpr`, in case it's a non-ok status.
46- #define XLA_RETURN_IF_ERROR (rexpr, ...) \
47- do { \
48- XLA_RETURN_IF_ERROR_IMPL (rexpr, XLA_STATUS_VAR, {}, ##__VA_ARGS__) \
56+ //
57+ // Example:
58+ //
59+ // XLA_RETURN_IF_ERROR(
60+ // FnThatReturnsStatus(),
61+ // "New error message."
62+ // );
63+ //
64+ // If the function call results in an ok status, execution continues. Otherwise,
65+ // we early return a non-ok status. Then, if `XLA_SHOW_CPP_ERROR_CONTEXT` is
66+ // set, the error shown will be:
67+ //
68+ // New error message. (at <cpp-source-file>:<line>)
69+ // Previous error message. (at <cpp-source-file>:<line>)
70+ // ...
71+ //
72+ #define XLA_RETURN_IF_ERROR (rexpr, ...) \
73+ do { \
74+ XLA_RETURN_IF_ERROR_IMPL_ (rexpr, XLA_STATUS_VAR, {}, ##__VA_ARGS__) \
4975 } while (false )
5076
5177// Propagates `rexpr`, in case it's a non-ok status. Otherwise, assign
5278// its result to `lhs`.
5379//
5480// Note 1: `lhs` might be a variable declarate, e.g:
5581//
56- // XLA_ASSIGN_OR_RETURN(int value, FnThatReturnsStatus(), ...);
57- //
5882// Note 2: this macro will be replaced by multiple statements that live on
5983// the scope it was called (see XLA_RETURN_IF_ERROR_IMPL).
6084//
61- #define XLA_ASSIGN_OR_RETURN (lhs, rexpr, ...) \
62- XLA_RETURN_IF_ERROR_IMPL (rexpr, XLA_STATUS_VAR, \
63- lhs = std::move(XLA_STATUS_VAR).value(); \
64- , ##__VA_ARGS__)
85+ // Example:
86+ //
87+ // XLA_ASSIGN_OR_RETURN(
88+ // int result,
89+ // FnThatReturnsStatus(),
90+ // "New error message."
91+ // );
92+ //
93+ // If the function call results in an ok status, execution continues with
94+ // `result` set to `ret.value()`, where `ret` is the returned value of the
95+ // function. Otherwise, we early return a non-ok status. Then, if
96+ // `XLA_SHOW_CPP_ERROR_CONTEXT` is set, the error shown will be:
97+ //
98+ // New error message. (at <cpp-source-file>:<line>)
99+ // Previous error message. (at <cpp-source-file>:<line>)
100+ // ...
101+ //
102+ #define XLA_ASSIGN_OR_RETURN (lhs, rexpr, ...) \
103+ XLA_RETURN_IF_ERROR_IMPL_ (rexpr, XLA_STATUS_VAR, \
104+ lhs = std::move(XLA_STATUS_VAR).value(), \
105+ ##__VA_ARGS__)
65106
66107// Maybe shows location information in the status message.
67108//
@@ -73,8 +114,13 @@ namespace torch_xla {
73114absl::Status MaybeWithLocation (const absl::Status& status, const char * file,
74115 int32_t line);
75116
76- const absl::Status& GetStatus (const absl::Status& status);
117+ // Returns an `absl::Status` from an `absl::Status`.
118+ // In this case, this function is a no-op. It simply returns the argument.
119+ inline const absl::Status& GetStatus (const absl::Status& status) {
120+ return status;
121+ }
77122
123+ // Returns an `absl::Status` from an `absl::StatusOr<T>`.
78124template <class T >
79125const absl::Status& GetStatus (const absl::StatusOr<T>& status) {
80126 return status.status ();
@@ -97,27 +143,32 @@ absl::Status MaybeWithNewMessage(const absl::Status& status, const char* file,
97143 int32_t line,
98144 std::string_view new_message = " "
99145
100- // Consumes the `status` and maybe throws an exception if `status` has
101- // a non-ok code.
146+ // Maybe throws an exception if `status` has a non-ok code.
102147//
103148// Ideally, this function should be used only used in the project's
104149// boundary, e.g. when we need to throw an exception for the user to see.
105- void ConsumeAndMaybeThrow (const absl::Status& status);
150+ void MaybeThrow (const absl::Status& status);
106151
107- // Consumes the `status`, either returning the value it holds (for
108- // ok status), or throwing an exception .
152+ // Either returns the value `status` holds, if it's an ok-status, or throw an
153+ // exception from its error status .
109154template <class T >
110- T ConsumeAndMaybeThrow (absl::StatusOr<T>& & status) {
111- ConsumeAndMaybeThrow (status.status ());
112- return std::move ( status) .value ();
155+ T& GetValueOrThrow (absl::StatusOr<T>& status) {
156+ MaybeThrow (status.status ());
157+ return status.value ();
113158}
114159
115160template <class T >
116- T ConsumeAndMaybeThrow (const absl::StatusOr<T>& status) {
117- ConsumeAndMaybeThrow (status.status ());
161+ const T& GetValueOrThrow (const absl::StatusOr<T>& status) {
162+ MaybeThrow (status.status ());
118163 return status.value ();
119164}
120165
166+ template <class T >
167+ T GetValueOrThrow (absl::StatusOr<T>&& status) {
168+ MaybeThrow (status.status ());
169+ return std::move (status).value ();
170+ }
171+
121172} // namespace torch_xla
122173
123174#endif // XLA_TORCH_XLA_CSRC_STATUS_H_
0 commit comments