Fixed #3536 (Preprocessor #if fails to correctly compare two #defined values)

lib/preprocessor.cpp

@@ -876,7 +876,25 @@ std::string Preprocessor::getdef(std::string line, bool def)
     return line;
 }
 
+/**
+ * Simplifies the variable map. For example if the map contains A=>B, B=>1, then A=>B is simplified to A=>1.
+ * @param [in,out] variables - a map of variable name to variable value. This map will be modified.
+ */
+static void simplifyVarMap(std::map<std::string, std::string> &variables)
+{
+    for (std::map<std::string, std::string>::iterator i = variables.begin(); i != variables.end(); ++i) {
+        std::string& varValue = i->second;
 
+        // TODO: 1. tokenize the value, replace each token like this.
+        // TODO: 2. handle function-macros too.
+
+        std::map<std::string, std::string>::iterator it = variables.find(varValue);
+        while (it != variables.end() && it != i) {
+            varValue = it->second;
+            it = variables.find(varValue);
+        }
+    }
+}
 
 std::list<std::string> Preprocessor::getcfgs(const std::string &filedata, const std::string &filename)
 {
@@ -998,6 +1016,7 @@ std::list<std::string> Preprocessor::getcfgs(const std::string &filedata, const
                     varmap[varname] = value;
                 }
 
+                simplifyVarMap(varmap);
                 simplifyCondition(varmap, def, false);
             }
 
@@ -1386,7 +1405,7 @@ void Preprocessor::simplifyCondition(const std::map<std::string, std::string> &c
         condition = "0";
 }
 
-bool Preprocessor::match_cfg_def(const std::map<std::string, std::string> &cfg, std::string def)
+bool Preprocessor::match_cfg_def(std::map<std::string, std::string> cfg, std::string def)
 {
     /*
         std::cout << "cfg: \"";
@@ -1401,6 +1420,7 @@ bool Preprocessor::match_cfg_def(const std::map<std::string, std::string> &cfg,
         std::cout << "def: \"" << def << "\"\n";
     */
 
+    simplifyVarMap(cfg);
     simplifyCondition(cfg, def, true);
 
     if (cfg.find(def) != cfg.end())

lib/preprocessor.h

@@ -206,7 +206,7 @@ public:
      * @param def condition
      * @return result when evaluating the condition
      */
-    bool match_cfg_def(const std::map<std::string, std::string> &cfg, std::string def);
+    bool match_cfg_def(std::map<std::string, std::string> cfg, std::string def);
 
     static void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings);
 

test/testpreprocessor.cpp

@@ -128,6 +128,8 @@ private:
         TEST_CASE(if_or_1);
         TEST_CASE(if_or_2);
 
+        TEST_CASE(if_macro_eq_macro); // #3536
+
         TEST_CASE(multiline1);
         TEST_CASE(multiline2);
         TEST_CASE(multiline3);
@@ -1501,6 +1503,23 @@ private:
         ASSERT_EQUALS("\na1;\n\n", preprocessor.getcode(code, "Y", "test.c"));
     }
 
+    void if_macro_eq_macro() {
+        const std::string code("#define A B\n"
+                               "#define B 1\n"
+                               "#define C 1\n"
+                               "#if A == C\n"
+                               "Wilma\n"
+                               "#else\n"
+                               "Betty\n"
+                               "#endif\n");
+        Settings settings;
+        Preprocessor preprocessor(&settings, this);
+        std::istringstream istr(code);
+        std::map<std::string, std::string> actual;
+        preprocessor.preprocess(istr, actual, "file.c");
+
+        ASSERT_EQUALS("\n\n\n\nWilma\n\n\n\n", actual[""]);
+    }
 
     void multiline1() {
         const char filedata[] = "#define str \"abc\"     \\\n"