From d55bb95d4d98277a2abcf5fbf07c622ea5472b09 Mon Sep 17 00:00:00 2001
From: Siu Kwan Lam <michael.lam.sk@gmail.com>
Date: Sun, 19 Aug 2012 21:27:28 -0700
Subject: [PATCH] Add translator to convert python code to llvm cbuilder
 construct

---
 translator.py | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 translator.py

diff --git a/translator.py b/translator.py
new file mode 100644
index 0000000..ac7338f
--- /dev/null
+++ b/translator.py
@@ -0,0 +1,91 @@
+# A handy translator that converts control flow into the appropriate
+# llvm_cbuilder constructs
+import inspect, functools, ast
+import pprint
+def translate(func):
+    # TODO use meta package
+    wrapper = functools.wraps(func)
+    source = inspect.getsource(func)
+    lines = list(source.splitlines())
+
+     # skip first two lines
+    first_line_len = len(lines[2])
+    indent = first_line_len - len(lines[2].lstrip())
+    source = '\n'.join(line[indent:] for line in lines[2:])
+
+    caller_frame = inspect.currentframe().f_back
+
+    tree = ast.parse(source)
+    tree = ExpandControlFlow().visit(tree)
+    tree = ast.fix_missing_locations(tree)
+
+    # prepare locals for execution
+    local_dict = locals()
+    local_dict.update(caller_frame.f_locals)
+    local_dict.update(caller_frame.f_globals)
+
+
+    return eval(compile(tree, '<string>', 'exec'))
+
+_if_else_template = '''
+with self.ifelse(__CONDITION__) as _ifelse_:
+    with _ifelse_.then():
+        __THEN__
+    with _ifelse_.otherwise():
+        __OTHERWISE__
+'''
+
+_return_template = 'self.ret(__RETURN__)'
+
+def load_template(string):
+    tree = ast.parse(string)  # return a Module
+    return tree.body[0]       # get the first item of body
+
+class ExpandControlFlow(ast.NodeTransformer):
+    def visit_If(self, node):
+        condition = node.test
+        mapping = {
+            '__CONDITION__' : node.test,
+            '__THEN__'      : node.body,
+            '__OTHERWISE__' : node.orelse,
+        }
+
+        ifelse = load_template(_if_else_template)
+        ifelse = NameReplacer(mapping).visit(ifelse)
+        newnode = ast.copy_location(ifelse, node)
+        return self.generic_visit(newnode)
+
+    def visit_Return(self, node):
+        mapping = {'__RETURN__' : node.value}
+        ret = load_template(_return_template)
+        repl = NameReplacer(mapping).visit(ret)
+        return ast.copy_location(repl, node)
+
+class NameReplacer(ast.NodeTransformer):
+    def __init__(self, mapping):
+        self.mapping = mapping
+
+    def visit_With(self, node):
+        if (len(node.body)==1
+          and isinstance(node.body[0], ast.Expr)
+          and isinstance(node.body[0].value, ast.Name)):
+            try:
+                repl = self.mapping.pop(node.body[0].value.id)
+            except KeyError:
+                pass
+            else:
+                old = node.body[0]
+                node.body = repl
+        return self.generic_visit(node)
+
+    def visit_Name(self, node):
+        if type(node.ctx) is ast.Load:
+            try:
+                repl = self.mapping.pop(node.id)
+            except KeyError:
+                pass
+            else:
+                if repl is not None and not isinstance(repl, list):
+                    return ast.copy_location(repl, node)
+        return node
+