Make ProgramOptions._as_bytes() public with backend support

cuda_core/cuda/core/experimental/_program.py

@@ -422,7 +422,26 @@ def __post_init__(self):
         if self.numba_debug:
             self._formatted_options.append("--numba-debug")
 
-    def _as_bytes(self):
+    def as_bytes(self) -> list[bytes]:
+        """Convert the formatted program options to a list of byte strings.
+
+        This method encodes each of the formatted options stored in this
+        `ProgramOptions` instance into byte strings, suitable for passing
+        to C libraries that calls the underlying compiler library.
+
+        Returns
+        -------
+        list[bytes]
+            A list of byte-encoded option strings. Each element represents
+            a single compilation option in the format expected by the underlying compiler library.
+
+        Examples
+        --------
+        >>> options = ProgramOptions(arch="sm_80", debug=True)
+        >>> byte_options = options.as_bytes()
+        >>> print(byte_options)
+        [b'-arch=sm_80', b'--device-debug']
+        """
         # TODO: allow tuples once NVIDIA/cuda-python#72 is resolved
         return list(o.encode() for o in self._formatted_options)
 
@@ -609,7 +628,7 @@ def compile(self, target_type, name_expressions=(), logs=None):
                         nvrtc.nvrtcAddNameExpression(self._mnff.handle, n.encode()),
                         handle=self._mnff.handle,
                     )
-            options = self._options._as_bytes()
+            options = self._options.as_bytes()
             handle_return(
                 nvrtc.nvrtcCompileProgram(self._mnff.handle, len(options), options),
                 handle=self._mnff.handle,

cuda_core/tests/test_program.py

@@ -411,3 +411,45 @@ def test_nvvm_program_options(init_cuda, nvvm_ir, options):
     assert ".visible .entry simple(" in ptx_text
 
     program.close()
+
+
+def test_program_options_as_bytes():
+    """Test that ProgramOptions.as_bytes() returns correct byte strings"""
+    # Test with various options
+    options = ProgramOptions(
+        arch="sm_80",
+        debug=True,
+        lineinfo=True,
+        max_register_count=32,
+        ftz=True,
+        use_fast_math=True,
+    )
+
+    byte_options = options.as_bytes()
+
+    # Verify the return type
+    assert isinstance(byte_options, list)
+    assert all(isinstance(opt, bytes) for opt in byte_options)
+
+    # Verify specific options are present in byte format
+    assert b"-arch=sm_80" in byte_options
+    assert b"--device-debug" in byte_options
+    assert b"--generate-line-info" in byte_options
+    assert b"--maxrregcount=32" in byte_options
+    assert b"--ftz=true" in byte_options
+    assert b"--use_fast_math" in byte_options
+
+
+def test_program_options_as_bytes_empty():
+    """Test that ProgramOptions.as_bytes() works with minimal options"""
+    # Test with minimal options (only defaults)
+    options = ProgramOptions()
+
+    byte_options = options.as_bytes()
+
+    # Should at least have arch option (automatically set based on Device if not provided)
+    assert isinstance(byte_options, list)
+    assert len(byte_options) > 0
+    assert all(isinstance(opt, bytes) for opt in byte_options)
+    # The arch option should be present (automatically determined from current device)
+    assert any(b"-arch=" in opt for opt in byte_options)