From 578531395ecbabd8179e31520c2832ac7d6d3765 Mon Sep 17 00:00:00 2001
From: Matthew Sotoudeh <matthew@masot.net>
Date: Thu, 27 Jul 2023 12:06:17 -0700
Subject: add dynamic typing example

---
 python/examples/dynamic_typing/dietpass | 50 +++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100755 python/examples/dynamic_typing/dietpass

(limited to 'python/examples/dynamic_typing/dietpass')

diff --git a/python/examples/dynamic_typing/dietpass b/python/examples/dynamic_typing/dietpass
new file mode 100755
index 0000000..5d15e19
--- /dev/null
+++ b/python/examples/dynamic_typing/dietpass
@@ -0,0 +1,50 @@
+#!/bin/python3
+import os
+import sys
+from dietc import *
+
+def main():
+    prog = Program(open(sys.argv[1], "rb").read())
+    for function in prog.functions:
+        fn_locals = function.locals()
+        start_i = function.code_start()
+        new_body = []
+        for op in function.body:
+            new_body.append(op)
+            # only look for casts to void
+            if " = ( " not in op.line: continue
+            if op.lhs_type(prog) != PointerType(BasicType("void")): continue
+            # if one is found, construct & annotate its type
+            rhs_type = prog.object_types[op[-2]]
+            type_ptr = describe_type(prog, rhs_type, new_body)
+            new_body.append(Instruction(
+                f"annotate_type({op[0]}, {type_ptr});"))
+        function.body = new_body
+    prog.preamble.append("#include <stddef.h>")
+    prog.print()
+
+def describe_type(prog, type_, new_body):
+    name = f"type_{count()}"
+    if isinstance(type_, BasicType):
+        new_body.append(Instruction(
+            f"void *{name} = make_basic(\"{type_.name}\", sizeof({type_.name}));"))
+    elif isinstance(type_, ArrayType):
+        base = describe_type(prog, type_.base, new_body)
+        new_body.append(Instruction(
+            f"void *{name} = make_array({base}, {type_.length});"))
+    elif isinstance(type_, PointerType):
+        base = describe_type(prog, type_.base, new_body)
+        new_body.append(Instruction(
+            f"void *{name} = make_pointer({base});"))
+    elif isinstance(type_, AggregateType):
+        tname = prog.type_to_name[type_]
+        new_body.append(Instruction(
+            f"void *{name} = make_struct(sizeof({tname}));"))
+        for fn, ft in reversed(type_.fields):
+            field = describe_type(prog, ft, new_body)
+            new_body.append(Instruction(
+                f"prepend_member({name}, {field}, \"{fn}\", offsetof({tname}, {fn}));"))
+    else: raise NotImplementedError
+    return name
+
+main()
-- 
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