From 66ae66b09c3300df2b306987b678cb209621b0f2 Mon Sep 17 00:00:00 2001
From: samczsun <github@samczsun.com>
Date: Tue, 23 Jun 2020 17:52:42 -0400
Subject: [PATCH] translate signed operations

---
 slither/slithir/operations/binary.py          | 26 ------------
 .../visitors/slithir/expression_to_slithir.py | 40 +++++++++++++++----
 2 files changed, 32 insertions(+), 34 deletions(-)

diff --git a/slither/slithir/operations/binary.py b/slither/slithir/operations/binary.py
index fce83aa6d..cd886197f 100644
--- a/slither/slithir/operations/binary.py
+++ b/slither/slithir/operations/binary.py
@@ -31,12 +31,6 @@ class BinaryType(Enum):
     ANDAND = 17  # &&
     OROR = 18  # ||
 
-    DIVISION_SIGNED = 19
-    MODULO_SIGNED = 20
-    LESS_SIGNED = 21
-    GREATER_SIGNED = 22
-    RIGHT_SHIFT_ARITHMETIC = 23
-
     @staticmethod
     def return_bool(operation_type):
         return operation_type in [BinaryType.OROR,
@@ -88,16 +82,6 @@ class BinaryType(Enum):
             return BinaryType.ANDAND
         if operation_type == '||':
             return BinaryType.OROR
-        if operation_type == "/'":
-            return BinaryType.DIVISION_SIGNED
-        if operation_type == "%'":
-            return BinaryType.MODULO_SIGNED
-        if operation_type == "<'":
-            return BinaryType.LESS_SIGNED
-        if operation_type == ">'":
-            return BinaryType.GREATER_SIGNED
-        if operation_type == ">>'":
-            return BinaryType.RIGHT_SHIFT_ARITHMETIC
 
         raise SlithIRError('get_type: Unknown operation type {})'.format(operation_type))
 
@@ -140,16 +124,6 @@ class BinaryType(Enum):
             return "&&"
         if self == BinaryType.OROR:
             return "||"
-        if self == BinaryType.DIVISION_SIGNED:
-            return "/'"
-        if self == BinaryType.MODULO_SIGNED:
-            return "%'"
-        if self == BinaryType.LESS_SIGNED:
-            return "<'"
-        if self == BinaryType.GREATER_SIGNED:
-            return ">'"
-        if self == BinaryType.RIGHT_SHIFT_ARITHMETIC:
-            return ">>'"
         raise SlithIRError("str: Unknown operation type {} {})".format(self, type(self)))
 
 
diff --git a/slither/visitors/slithir/expression_to_slithir.py b/slither/visitors/slithir/expression_to_slithir.py
index 1fea831a9..99d41d3e5 100644
--- a/slither/visitors/slithir/expression_to_slithir.py
+++ b/slither/visitors/slithir/expression_to_slithir.py
@@ -55,13 +55,17 @@ _binary_to_binary = {
     BinaryOperationType.NOT_EQUAL: BinaryType.NOT_EQUAL,
     BinaryOperationType.ANDAND: BinaryType.ANDAND,
     BinaryOperationType.OROR: BinaryType.OROR,
-    BinaryOperationType.DIVISION_SIGNED: BinaryType.DIVISION_SIGNED,
-    BinaryOperationType.MODULO_SIGNED: BinaryType.MODULO_SIGNED,
-    BinaryOperationType.LESS_SIGNED: BinaryType.LESS_SIGNED,
-    BinaryOperationType.GREATER_SIGNED: BinaryType.GREATER_SIGNED,
-    BinaryOperationType.RIGHT_SHIFT_ARITHMETIC: BinaryType.RIGHT_SHIFT_ARITHMETIC,
 }
 
+_signed_to_unsigned = {
+    BinaryOperationType.DIVISION_SIGNED: BinaryType.DIVISION,
+    BinaryOperationType.MODULO_SIGNED: BinaryType.MODULO,
+    BinaryOperationType.LESS_SIGNED: BinaryType.LESS,
+    BinaryOperationType.GREATER_SIGNED: BinaryType.GREATER,
+    BinaryOperationType.RIGHT_SHIFT_ARITHMETIC: BinaryType.RIGHT_SHIFT,
+}
+
+
 def convert_assignment(left, right, t, return_type):
     if t == AssignmentOperationType.ASSIGN:
         return Assignment(left, right, return_type)
@@ -147,9 +151,29 @@ class ExpressionToSlithIR(ExpressionVisitor):
         right = get(expression.expression_right)
         val = TemporaryVariable(self._node)
 
-        operation = Binary(val, left, right, _binary_to_binary[expression.type])
-        operation.set_expression(expression)
-        self._result.append(operation)
+        if expression.type in _signed_to_unsigned:
+            new_left = TemporaryVariable(self._node)
+            conv_left = TypeConversion(new_left, left, ElementaryType('int256'))
+            conv_left.set_expression(expression)
+            self._result.append(conv_left)
+
+            if expression.type != BinaryOperationType.RIGHT_SHIFT_ARITHMETIC:
+                new_right = TemporaryVariable(self._node)
+                conv_right = TypeConversion(new_right, right, ElementaryType('int256'))
+                conv_right.set_expression(expression)
+                self._result.append(conv_right)
+            else:
+                new_right = right
+
+            operation = Binary(val, new_left, new_right, _signed_to_unsigned[expression.type])
+            operation.set_expression(expression)
+            val.set_type(ElementaryType('uint256')) # overwrite the result from Binary() for now
+            self._result.append(operation)
+        else:
+            operation = Binary(val, left, right, _binary_to_binary[expression.type])
+            operation.set_expression(expression)
+            self._result.append(operation)
+
         set_val(expression, val)
 
     def _post_call_expression(self, expression):