Fix control flow for sequences of conditional assignments (#337)

CHANGES.md

+0.7-dev
+====
+
 0.6 (2022-06)
 ====
 

Cargo.lock

@@ -128,7 +128,7 @@ dependencies = [
 
 [[package]]
 name = "cwe_checker"
-version = "0.6.0"
+version = "0.7.0-dev"
 dependencies = [
  "cwe_checker_lib",
  "directories",
@@ -151,7 +151,7 @@ dependencies = [
 
 [[package]]
 name = "cwe_checker_lib"
-version = "0.6.0"
+version = "0.7.0-dev"
 dependencies = [
  "anyhow",
  "apint",

src/caller/Cargo.toml

 [package]
 name = "cwe_checker"
-version = "0.6.0"
+version = "0.7.0-dev"
 authors = ["Nils-Edvin Enkelmann <nils-edvin.enkelmann@fkie.fraunhofer.de>"]
 edition = "2021"
 

src/cwe_checker_lib/Cargo.toml

 [package]
 name = "cwe_checker_lib"
-version = "0.6.0"
+version = "0.7.0-dev"
 authors = ["Nils-Edvin Enkelmann <nils-edvin.enkelmann@fkie.fraunhofer.de>"]
 edition = "2021"
 

src/cwe_checker_lib/src/intermediate_representation/project.rs

 use super::*;
+use crate::utils::log::LogMessage;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
+
+/// Contains implementation of the block duplication normalization pass.
 mod block_duplication_normalization;
-use crate::utils::log::LogMessage;
 use block_duplication_normalization::*;
+/// Contains implementation of the propagate control flow normalization pass.
+mod propagate_control_flow;
+use propagate_control_flow::*;
 
 /// The `Project` struct is the main data structure representing a binary.
 ///
@@ -225,7 +230,10 @@ impl Project {
     /// - Duplicate blocks so that if a block is contained in several functions, each function gets its own unique copy.
     /// - Propagate input expressions along variable assignments.
     /// - Replace trivial expressions like `a XOR a` with their result.
-    /// - Remove dead register assignments
+    /// - Remove dead register assignments.
+    /// - Propagate the control flow along chains of conditionals with the same condition.
+    /// - Substitute bitwise `AND` and `OR` operations with the stack pointer
+    /// in cases where the result is known due to known stack pointer alignment.
     #[must_use]
     pub fn normalize(&mut self) -> Vec<LogMessage> {
         let mut logs =
@@ -234,6 +242,7 @@ impl Project {
         self.propagate_input_expressions();
         self.substitute_trivial_expressions();
         crate::analysis::dead_variable_elimination::remove_dead_var_assignments(self);
+        propagate_control_flow(self);
         logs.append(
             crate::analysis::stack_alignment_substitution::substitute_and_on_stackpointer(self)
                 .unwrap_or_default()