add characterize function for ICD source build caching

pyopencl/__init__.py

@@ -508,16 +508,14 @@ def build(self, options=None, devices=None, cache_dir=None):
             cache_dir = getattr(self._context, "cache_dir", None)
 
         build_descr = None
-        no_cache = _PYOPENCL_NO_CACHE
-        # Turn off caching when using pocl to avoid extra compile from
-        # get_info(BINARIES). See https://github.com/inducer/pyopencl/issues/731.
-        from pyopencl.characterize import get_pocl_version
-        no_cache |= get_pocl_version(self._context.devices[0].platform) is not None
-        if no_cache and self._prg is None:
+        from pyopencl.characterize import has_src_build_cache
+        if (
+                (_PYOPENCL_NO_CACHE or has_src_build_cache(self._context.devices[0]))
+                and self._prg is None):
             if _PYOPENCL_NO_CACHE:
                 build_descr = "uncached source build (cache disabled by user)"
             else:
-                build_descr = "uncached source build (cache disabled for pocl)"
+                build_descr = "source build via ICD cache"
             self._prg = _cl._Program(self._context, self._source)
 
         from time import time

pyopencl/characterize/__init__.py

@@ -429,3 +429,13 @@ def has_fine_grain_buffer_svm_atomics(dev):
 def has_fine_grain_system_svm_atomics(dev):
     return has_fine_grain_system_svm(dev) and bool(dev.svm_capabilities
                 & cl.device_svm_capabilities.ATOMICS)
+
+
+def has_src_build_cache(dev):
+    """
+    Return *True* if *dev* has internal support for caching builds from source,
+    *False* if it doesn't, and *None* if unknown.
+    """
+    if get_pocl_version(dev.platform) is not None:
+        return True
+    return None