Implement store.

stepper.py

@@ -64,7 +64,18 @@ def step(insns, terminator, blocks, stack_frames, ssa_env, global_env, heap,
     elif isinstance(next_insn, ll.Load):
         TODO('Load')
     elif isinstance(next_insn, ll.Store):
-        TODO('Store')
+        ty = next_insn.ty
+        value = next_insn.value
+        location = next_insn.location
+
+        value_v = eval_oper(value, ssa_env, global_env)
+        location_v = eval_oper(location, ssa_env, global_env)
+
+        # TODO
+        print('heap[{}] <- {}'
+              .format(location_v, value_v))
+
+        heap[location_v] = value_v
     elif isinstance(next_insn, ll.Icmp):
         cnd = next_insn.cnd
         left = next_insn.left
@@ -333,7 +344,7 @@ def gogo():
     data = r'''
 define i64 @tigermain (i64 %U_mainSL_8, i64 %U_mainDummy_9) {
     %a = alloca i64
-    %b = alloca i64
+    store i64 9, i64* %a
     ret i64 77
 }
 '''