refactor: initcode generation (#3574)

move internal function generation to after ctor generation. prior to
this commit, the existing code relies on the fact that the code
generation of runtime internal functions properly sets the frame
information of the ctor's callees. if this precondition is not met in
the future, the compiler could panic because the memory allocation info
will not be available.

chainsec june 2023 review 6.2

vyper/codegen/module.py

@@ -442,6 +442,20 @@ def generate_ir_for_module(global_ctx: GlobalContext) -> tuple[IRnode, IRnode]:
     deploy_code: List[Any] = ["seq"]
     immutables_len = global_ctx.immutable_section_bytes
     if init_function:
+        # cleanly rerun codegen for internal functions with `is_ctor_ctx=True`
+        ctor_internal_func_irs = []
+        internal_functions = [f for f in runtime_functions if _is_internal(f)]
+        for f in internal_functions:
+            init_func_t = init_function._metadata["type"]
+            if f.name not in init_func_t.recursive_calls:
+                # unreachable code, delete it
+                continue
+
+            func_ir = _ir_for_internal_function(f, global_ctx, is_ctor_context=True)
+            ctor_internal_func_irs.append(func_ir)
+
+        # generate init_func_ir after callees to ensure they have analyzed
+        # memory usage.
         # TODO might be cleaner to separate this into an _init_ir helper func
         init_func_ir = _ir_for_fallback_or_ctor(init_function, global_ctx, is_ctor_context=True)
 
@@ -468,19 +482,9 @@ def generate_ir_for_module(global_ctx: GlobalContext) -> tuple[IRnode, IRnode]:
             deploy_code.append(["iload", max(0, immutables_len - 32)])
 
         deploy_code.append(init_func_ir)
-
         deploy_code.append(["deploy", init_mem_used, runtime, immutables_len])
-
-        # internal functions come after everything else
-        internal_functions = [f for f in runtime_functions if _is_internal(f)]
-        for f in internal_functions:
-            init_func_t = init_function._metadata["type"]
-            if f.name not in init_func_t.recursive_calls:
-                # unreachable code, delete it
-                continue
-
-            func_ir = _ir_for_internal_function(f, global_ctx, is_ctor_context=True)
-            deploy_code.append(func_ir)
+        # internal functions come at end of initcode
+        deploy_code.extend(ctor_internal_func_irs)
 
     else:
         if immutables_len != 0: