compiler: Implement len() for ndarrays

artiq/compiler/transforms/llvm_ir_generator.py

@@ -1170,6 +1170,10 @@ class LLVMIRGenerator:
             return get_outer(self.map(env), env.type)
         elif insn.op == "len":
             collection, = insn.operands
+            if builtins.is_array(collection.type):
+                # Return length of outermost dimension.
+                shape = self.llbuilder.extract_value(self.map(collection), 0)
+                return self.llbuilder.load(self.llbuilder.extract_value(shape, 0))
             return self.llbuilder.extract_value(self.map(collection), 1)
         elif insn.op in ("printf", "rtio_log"):
             # We only get integers, floats, pointers and strings here.

artiq/test/lit/integration/array.py

@@ -2,7 +2,9 @@
 # REQUIRES: exceptions
 
 ary = array([1, 2, 3])
+assert len(ary) == 3
 # FIXME: Implement ndarray indexing
 # assert [x*x for x in ary] == [1, 4, 9]
 
 matrix = array([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
+assert len(matrix) == 2