compiler: Introduce operator lookup hook

devito/arch/archinfo.py

@@ -16,7 +16,7 @@
 from packaging.version import InvalidVersion, parse
 
 from devito.logger import warning
-from devito.tools import all_equal, as_tuple, memoized_func
+from devito.tools import all_equal, as_tuple, frozendict, memoized_func
 
 __all__ = [  # noqa: RUF022
     'platform_registry', 'get_cpu_info', 'get_gpu_info', 'get_visible_devices',
@@ -855,6 +855,13 @@ def supports(self, query, language=None):
         """
         return False
 
+    @cached_property
+    def digest(self):
+        fields = ('brand', 'logical', 'physical')
+        cpuinfo = get_cpu_info()
+        # TODO: Is it necessary to homogenise brand info?
+        return frozendict({k: cpuinfo[k] for k in fields})
+
 
 class Cpu64(Platform):
 
@@ -1093,6 +1100,15 @@ def limits(self, compiler=None, language=None):
             'max-block-dims': 3,
         }
 
+    @cached_property
+    def digest(self):
+        fields = ('architecture', 'product', 'vendor')
+        gpuinfo = get_gpu_info()
+        mapper = {k: gpuinfo[k] for k in fields}
+        mapper['mem.total'] = gpuinfo['mem.total']()
+
+        return frozendict(mapper)
+
 
 class IntelDevice(Device):
 

devito/operator/operator.py

@@ -182,6 +182,12 @@ def __new__(cls, expressions, **kwargs):
         cls._check_kwargs(**kwargs)
         expressions = cls._sanitize_exprs(expressions, **kwargs)
 
+        # Hook for retrieval of preexisting operators
+        # TODO: should this emit timing info if an operator is retrieved
+        maybe_op = cls._retrieve_op(expressions, **kwargs)
+        if maybe_op:
+            return maybe_op
+
         # Lower to a JIT-compilable object
         with timed_region('op-compile') as r:
             try:
@@ -215,6 +221,10 @@ def _sanitize_exprs(cls, expressions, **kwargs):
 
         return expressions
 
+    @classmethod
+    def _retrieve_op(cls, expressions, **kwargs):
+        return
+
     @classmethod
     def _build(cls, expressions, **kwargs):
         # Python- (i.e., compile-) and C-level (i.e., run-time) performance

devito/types/equation.py

@@ -183,6 +183,9 @@ def xreplace(self, rules):
         return self.func(self.lhs.xreplace(rules), self.rhs.xreplace(rules))
 
     def __str__(self):
+        if self._subdomain is not None:
+            return (f"{self.__class__.__name__}({self.lhs}, {self.rhs},"
+                    f" subdomain={self._subdomain})")
         return f"{self.__class__.__name__}({self.lhs}, {self.rhs})"
 
     __repr__ = __str__