Fixed #982 (Preprocessor: detects and remove conditions which always true)

lib/preprocessor.cpp

@@ -832,6 +832,22 @@ std::list<std::string> Preprocessor::getcfgs(const std::string &filedata, const
                 return ret;
             }
 
+            // Replace defined constants
+            {
+                std::map<std::string, std::string> varmap;
+                for (std::set<std::string>::const_iterator it = defines.begin(); it != defines.end(); ++it)
+                {
+                    std::string::size_type pos = (*it).find("=");
+                    if (pos == std::string::npos)
+                        continue;
+                    const std::string varname((*it).substr(0, pos));
+                    const std::string value((*it).substr(pos + 1));
+                    varmap[varname] = value;
+                }
+
+                simplifyCondition(varmap, def);
+            }
+
             if (! deflist.empty() && line.find("#elif ") == 0)
                 deflist.pop_back();
             deflist.push_back(def);
@@ -999,12 +1015,53 @@ std::list<std::string> Preprocessor::getcfgs(const std::string &filedata, const
 }
 
 
+void Preprocessor::simplifyCondition(const std::map<std::string, std::string> &variables, std::string &condition)
+{
+    Tokenizer tokenizer;
+    std::istringstream istr(condition.c_str());
+    tokenizer.tokenize(istr, "");
+
+    // replace variable names with values..
+    for (Token *tok = const_cast<Token *>(tokenizer.tokens()); tok; tok = tok->next())
+    {
+        const std::map<std::string, std::string>::const_iterator it = variables.find(tok->str());
+        if (it != variables.end())
+            tok->str(it->second);
+    }
+
+    // simplify calculations..
+    tokenizer.simplifyCalculations();
+
+    if (!tokenizer.tokens()->tokAt(3) && Token::Match(tokenizer.tokens(), "%num% ==|!=|<=|>=|<|> %num%"))
+    {
+        const std::string op1(tokenizer.tokens()->str());
+        const std::string cmp(tokenizer.tokens()->strAt(1));
+        const std::string op2(tokenizer.tokens()->strAt(2));
+        if (cmp == "==")
+            condition = (op1 == op2) ? "1" : "0";
+        else if (cmp == "!=")
+            condition = (op1 != op2) ? "1" : "0";
+        else if (cmp == "<=")
+            condition = (op1 <= op2) ? "1" : "0";
+        else if (cmp == ">=")
+            condition = (op1 >= op2) ? "1" : "0";
+        else if (cmp == "<")
+            condition = (op1 < op2) ? "1" : "0";
+        else if (cmp == ">")
+            condition = (op1 > op2) ? "1" : "0";
+        return;
+    }
+}
+
+
 
 bool Preprocessor::match_cfg_def(const std::map<std::string, std::string> &cfg, std::string def)
 {
     //std::cout << "cfg: \"" << cfg << "\"  ";
     //std::cout << "def: \"" << def << "\"";
 
+    simplifyCondition(cfg, def);
+
     if (cfg.find(def) != cfg.end())
         return true;
 

lib/preprocessor.h

@@ -77,6 +77,13 @@ public:
      */
     static std::string getcode(const std::string &filedata, std::string cfg, const std::string &filename, ErrorLogger *errorLogger);
 
+    /**
+     * simplify condition
+     * @param variables Variable values
+     * @param condition The condition to simplify
+     */
+    static void simplifyCondition(const std::map<std::string, std::string> &variables, std::string &condition);
+
 protected:
 
     static void writeError(const std::string &fileName, const std::string &code, size_t pos, ErrorLogger *errorLogger, const std::string &errorType, const std::string &errorText);

lib/tokenize.h

@@ -126,6 +126,13 @@ public:
      */
     std::map<std::string, ClassInfo> _classInfoList;
 
+    /**
+     * Simplify constant calculations such as "1+2" => "3"
+     * @return true if modifications to token-list are done.
+     *         false if no modifications are done.
+     */
+    bool simplifyCalculations();
+
 #ifndef _MSC_VER
 private:
 #endif
@@ -272,13 +279,6 @@ private:
      */
     bool simplifyRedundantParanthesis();
 
-    /**
-     * Simplify constant calculations such as "1+2" => "3"
-     * @return true if modifications to token-list are done.
-     *         false if no modifications are done.
-     */
-    bool simplifyCalculations();
-
     /**
      * Simplify functions like "void f(x) int x; {"
      * into "void f(int x) {"

test/testpreprocessor.cpp

@@ -99,6 +99,7 @@ private:
         TEST_CASE(if_cond4);
         TEST_CASE(if_cond5);
         TEST_CASE(if_cond6);
+        TEST_CASE(if_cond7);
 
         TEST_CASE(multiline1);
         TEST_CASE(multiline2);
@@ -606,8 +607,8 @@ private:
             cfg["A"] = "1";
             cfg["B"] = "2";
 
-            TODO_ASSERT_EQUALS(true, Preprocessor::match_cfg_def(cfg, "A==1"));
+            ASSERT_EQUALS(true, Preprocessor::match_cfg_def(cfg, "A==1"));
-            TODO_ASSERT_EQUALS(true, Preprocessor::match_cfg_def(cfg, "A<2"));
+            ASSERT_EQUALS(true, Preprocessor::match_cfg_def(cfg, "A<2"));
             ASSERT_EQUALS(false, Preprocessor::match_cfg_def(cfg, "A==2"));
             ASSERT_EQUALS(false, Preprocessor::match_cfg_def(cfg, "A<1"));
             TODO_ASSERT_EQUALS(true, Preprocessor::match_cfg_def(cfg, "A>=1&&B<=A"));
@@ -798,6 +799,25 @@ private:
         ASSERT_EQUALS("[file.c:2]: (error) mismatching number of '(' and ')' in this line: defined(A)&&defined(B))\n", errout.str());
     }
 
+    void if_cond7()
+    {
+        const char filedata[] = "#define A 1\n"
+                                "#if A==1\n"
+                                "a1;\n"
+                                "#endif\n";
+
+        // Preprocess => actual result..
+        std::istringstream istr(filedata);
+        std::map<std::string, std::string> actual;
+        const Settings settings;
+        Preprocessor preprocessor(&settings, this);
+        preprocessor.preprocess(istr, actual, "file.c");
+
+        // Compare results..
+        ASSERT_EQUALS(1, actual.size());
+        ASSERT_EQUALS("\n\na1;\n\n", actual[""]);
+    }
+
 
     void multiline1()
     {
@@ -1657,8 +1677,8 @@ private:
             preprocessor.preprocess(istr, actual, "file.c");
 
             // Compare results..
-            TODO_ASSERT_EQUALS("\n\n1\n\n", actual[""]);
+            ASSERT_EQUALS("\n\n1\n\n", actual[""]);
-            TODO_ASSERT_EQUALS(1, actual.size());
+            ASSERT_EQUALS(1, actual.size());
         }
 
         {
@@ -1674,8 +1694,8 @@ private:
             preprocessor.preprocess(istr, actual, "file.c");
 
             // Compare results..
-            TODO_ASSERT_EQUALS("\n\n1\n\n", actual[""]);
+            ASSERT_EQUALS("\n\n1\n\n", actual[""]);
-            TODO_ASSERT_EQUALS(1, actual.size());
+            ASSERT_EQUALS(1, actual.size());
         }
     }