[mlir] use enum for C MlirLogicalResult

[ftynse]

Summary

Depends On D88736

mlir/include/mlir-c/Support.h

 MlirStringRef mlirStringRefCreateFromCString(const char *str);
 
 /*============================================================================*/
 /* MlirLogicalResult.                                                         */
 /*============================================================================*/
 
 /** A logical result value, essentially a boolean with named states. LLVM
  * convention for using boolean values to designate success or failure of an
- * operation is a moving target, so MLIR opted for an explicit class.
- * Instances of MlirLogicalResult must only be inspected using the associated
- * functions. */
-struct MlirLogicalResult {
-  int8_t value;
-};
-typedef struct MlirLogicalResult MlirLogicalResult;
-
-/** Checks if the given logical result represents a success. */
-inline int mlirLogicalResultIsSuccess(MlirLogicalResult res) {
-  return res.value != 0;
-}
-
-/** Checks if the given logical result represents a failure. */
-inline int mlirLogicalResultIsFailure(MlirLogicalResult res) {
-  return res.value == 0;
-}
-
-/** Creates a logical result representing a success. */
-inline static MlirLogicalResult mlirLogicalResultSuccess() {
-  MlirLogicalResult res = {1};
-  return res;
-}
-
-/** Creates a logical result representing a failure. */
-inline static MlirLogicalResult mlirLogicalResultFailure() {
-  MlirLogicalResult res = {0};
-  return res;
-}
+ * operation is a moving target, so MLIR opted for an explicit class. In C API,
+ * this is reflected as a two-element enum that is expected to be used in
+ * conjunction with explicit checks. */
+enum MlirLogicalResult { MlirLogicalResultFailure, MlirLogicalResultSuccess };
+typedef enum MlirLogicalResult MlirLogicalResult;
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // MLIR_C_SUPPORT_H

mlir/include/mlir/CAPI/Support.h

 
 /// Creates a StringRef out of its MLIR C API equivalent.
 inline llvm::StringRef unwrap(MlirStringRef ref) {
   return llvm::StringRef(ref.data, ref.length);
 }
 
 inline MlirLogicalResult wrap(mlir::LogicalResult res) {
   if (mlir::succeeded(res))
-    return mlirLogicalResultSuccess();
-  return mlirLogicalResultFailure();
+    return MlirLogicalResultSuccess;
+  return MlirLogicalResultFailure;
 }
 
 inline mlir::LogicalResult unwrap(MlirLogicalResult res) {
-  return mlir::success(mlirLogicalResultIsSuccess(res));
+  return mlir::success(res == MlirLogicalResultSuccess);
 }
 
 #endif // MLIR_CAPI_SUPPORT_H

mlir/test/CAPI/ir.c

 MlirLogicalResult errorHandler(MlirDiagnostic diagnostic) {
   fprintf(stderr, "processing diagnostic <<\n");
   mlirDiagnosticPrint(diagnostic, printToStderr, NULL);
   fprintf(stderr, "\n");
   MlirLocation loc = mlirDiagnosticGetLocation(diagnostic);
   mlirLocationPrint(loc, printToStderr, NULL);
   assert(mlirDiagnosticGetNumNotes(diagnostic) == 0);
   fprintf(stderr, ">> end of diagnostic\n");
-  return mlirLogicalResultSuccess();
+  return MlirLogicalResultSuccess;
 }
 
 void testDiagnostics() {
   MlirContext ctx = mlirContextCreate();
   MlirDiagnosticHandlerID id =
       mlirContextAttachDiagnosticHandler(ctx, errorHandler);
   MlirLocation loc = mlirLocationUnknownGet(ctx);
   mlirEmitError(loc, "test diagnostics");