artiq_compile: actually disable attribute writeback.

I wrote both halves of this condition but forgot to hook
them together.

Fixes #586.

artiq/compiler/module.py

@@ -40,7 +40,8 @@ class Source:
             return cls(source.Buffer(f.read(), filename, 1), engine=engine)
 
 class Module:
-    def __init__(self, src, ref_period=1e-6):
+    def __init__(self, src, ref_period=1e-6, attribute_writeback=True):
+        self.attribute_writeback = attribute_writeback
         self.engine = src.engine
         self.embedding_map = src.embedding_map
         self.name = src.name
@@ -79,7 +80,8 @@ class Module:
         llvm_ir_generator = transforms.LLVMIRGenerator(
             engine=self.engine, module_name=self.name, target=target,
             embedding_map=self.embedding_map)
-        return llvm_ir_generator.process(self.artiq_ir, attribute_writeback=True)
+        return llvm_ir_generator.process(self.artiq_ir,
+            attribute_writeback=self.attribute_writeback)
 
     def __repr__(self):
         printer = types.TypePrinter()

artiq/coredevice/core.py

@@ -81,7 +81,7 @@ class Core:
         self.core = self
         self.comm.core = self
 
-    def compile(self, function, args, kwargs, set_result=None, with_attr_writeback=True):
+    def compile(self, function, args, kwargs, set_result=None, attribute_writeback=True):
         try:
             engine = _DiagnosticEngine(all_errors_are_fatal=True)
 
@@ -89,7 +89,9 @@ class Core:
             stitcher.stitch_call(function, args, kwargs, set_result)
             stitcher.finalize()
 
-            module = Module(stitcher, ref_period=self.ref_period)
+            module = Module(stitcher,
+                ref_period=self.ref_period,
+                attribute_writeback=attribute_writeback)
             target = OR1KTarget()
 
             library = target.compile_and_link([module])

artiq/frontend/artiq_compile.py

@@ -55,7 +55,7 @@ def main():
 
         object_map, kernel_library, _, _ = \
             core.compile(exp.run, [exp_inst], {},
-                         with_attr_writeback=False)
+                         attribute_writeback=False)
     except CompileError as error:
         return
     finally: