compiler: Fix crash on multiple types with the same name

The original fix in 21574bdfa9
was incomplete, as it only addressed the TInstance types, but
not their linked (typ.constructor) TConstructor instances.

This would (potentially among other issues) cause assertion
errors in llvm_ir_generator due to the wrong associated globals
being referenced; see added test case for an example that
previously caused such a crash.

Also modified the name collision detection from O(len(type_map))
(so quadratic overall in the number of custom types) to cache
names in sets for O(1) lookup.

artiq/compiler/embedding.py

@@ -52,7 +52,14 @@ class EmbeddingMap:
         self.object_forward_map = {}
         self.object_reverse_map = {}
         self.module_map = {}
+
+        # type_map connects the host Python `type` to the pair of associated
+        # `(TInstance, TConstructor)`s. The `used_…_names` sets cache the
+        # respective `.name`s for O(1) collision avoidance.
         self.type_map = {}
+        self.used_instance_type_names = set()
+        self.used_constructor_type_names = set()
+
         self.function_map = {}
         self.str_forward_map = {}
         self.str_reverse_map = {}
@@ -98,16 +105,6 @@ class EmbeddingMap:
 
     # Types
     def store_type(self, host_type, instance_type, constructor_type):
-        self._rename_type(instance_type)
-        self.type_map[host_type] = (instance_type, constructor_type)
-
-    def retrieve_type(self, host_type):
-        return self.type_map[host_type]
-
-    def has_type(self, host_type):
-        return host_type in self.type_map
-
-    def _rename_type(self, new_instance_type):
         # Generally, user-defined types that have exact same name (which is to say, classes
         # defined inside functions) do not pose a problem to the compiler. The two places which
         # cannot handle this are:
@@ -116,12 +113,29 @@ class EmbeddingMap:
         # Since handling #2 requires renaming on ARTIQ side anyway, it's more straightforward
         # to do it once when embedding (since non-embedded code cannot define classes in
         # functions). Also, easier to debug.
-        n = 0
-        for host_type in self.type_map:
-            instance_type, constructor_type = self.type_map[host_type]
-            if instance_type.name == new_instance_type.name:
-                n += 1
-                new_instance_type.name = "{}.{}".format(new_instance_type.name, n)
+        suffix = 0
+        new_instance_name = instance_type.name
+        new_constructor_name = constructor_type.name
+        while True:
+            if (new_instance_name not in self.used_instance_type_names
+                    and new_constructor_name not in self.used_constructor_type_names):
+                break
+            suffix += 1
+            new_instance_name = f"{instance_type.name}.{suffix}"
+            new_constructor_name = f"{constructor_type.name}.{suffix}"
+
+        self.used_instance_type_names.add(new_instance_name)
+        instance_type.name = new_instance_name
+        self.used_constructor_type_names.add(new_constructor_name)
+        constructor_type.name = new_constructor_name
+
+        self.type_map[host_type] = (instance_type, constructor_type)
+
+    def retrieve_type(self, host_type):
+        return self.type_map[host_type]
+
+    def has_type(self, host_type):
+        return host_type in self.type_map
 
     def attribute_count(self):
         count = 0

artiq/test/lit/embedding/class_same_name.py

@@ -0,0 +1,51 @@
+# RUN: %python -m artiq.compiler.testbench.embedding %s
+
+from artiq.language.core import *
+
+
+class InnerA:
+    def __init__(self, val):
+        self.val = val
+
+    @kernel
+    def run_once(self):
+        return self.val
+
+
+class InnerB:
+    def __init__(self, val):
+        self.val = val
+
+    @kernel
+    def run_once(self):
+        return self.val
+
+
+def make_runner(InnerCls, val):
+    class Runner:
+        def __init__(self):
+            self.inner = InnerCls(val)
+
+        @kernel
+        def run_once(self):
+            return self.inner.run_once()
+
+    return Runner()
+
+
+class Parent:
+    def __init__(self):
+        self.a = make_runner(InnerA, 1)
+        self.b = make_runner(InnerB, 42.0)
+
+    @kernel
+    def run_once(self):
+        return self.a.run_once() + self.b.run_once()
+
+
+parent = Parent()
+
+
+@kernel
+def entrypoint():
+    parent.run_once()