Fix #14614: Optionally provide comments in preprocessor output (BuildCache)

cli/cmdlineparser.cpp

@@ -461,6 +461,11 @@ CmdLineParser::Result CmdLineParser::parseFromArgs(int argc, const char* const a
             mSettings.quiet = true;
         }
 
+        // -CC
+        else if (std::strcmp(argv[i], "-CC") == 0) {
+            mSettings.keepComments = true;
+        }
+
         // Include paths
         else if (std::strncmp(argv[i], "-I", 2) == 0) {
             std::string path;
@@ -1737,6 +1742,12 @@ CmdLineParser::Result CmdLineParser::parseFromArgs(int argc, const char* const a
     if (mSettings.basePaths.empty() && mSettings.relativePaths)
         mSettings.basePaths = mPathNames;
 
+    if (mSettings.keepComments && !mSettings.preprocessOnly) {
+        mLogger.printError("-CC may only be used on conjunciton with -E");
+        return Result::Fail;
+    }
+
+
     return Result::Success;
 }
 
@@ -1807,6 +1818,7 @@ void CmdLineParser::printHelp() const
         "                         Example: '-DDEBUG=1 -D__cplusplus'.\n"
         "    -E                   Print preprocessor output on stdout and don't do any\n"
         "                         further processing.\n"
+        "    -CC                  Do not remove comments during preprocessing (requires -E).\n"
         "    --enable=<severity>  Enable additional checks grouped by severity. The available\n"
         "                         severities are:\n"
         "                          * warning\n"

lib/cppcheck.cpp

@@ -1024,7 +1024,8 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
         // Parse comments and then remove them
         mLogger->addRemarkComments(preprocessor.getRemarkComments());
         preprocessor.inlineSuppressions(mSuppressions.nomsg);
-        preprocessor.removeComments();
+        if (!mSettings.keepComments)
+            preprocessor.removeComments();
 
         // Get directives
         std::list<Directive> directives;
@@ -1054,7 +1055,8 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
                 // Do preprocessing on included file
                 mLogger->addRemarkComments(preprocessor.getRemarkComments(data.tokens));
                 preprocessor.inlineSuppressions(data.tokens, mSuppressions.nomsg);
-                Preprocessor::removeComments(data.tokens);
+                if (!mSettings.keepComments)
+                    Preprocessor::removeComments(data.tokens);
                 Preprocessor::createDirectives(data.tokens, directives);
                 Preprocessor::simplifyPragmaAsm(data.tokens);
                 // Discover new configurations from included file

lib/preprocessor.cpp

@@ -890,7 +890,8 @@ simplecpp::TokenList Preprocessor::preprocess(const std::string &cfgStr, std::ve
     mMacroUsage = std::move(macroUsage);
     mIfCond = std::move(ifCond);
 
-    tokens2.removeComments();
+    if (!mSettings.keepComments)
+        tokens2.removeComments();
 
     return tokens2;
 }
@@ -919,6 +920,13 @@ std::string Preprocessor::getcode(const std::string &cfgStr, std::vector<std::st
         if (!tok->macro.empty())
             ret << Preprocessor::macroChar;
         ret << tok->str();
+
+        if (tok->comment)
+            line += std::count_if(tok->str().cbegin(),
+                                  tok->str().cend(),
+                                  [](char c) {
+                return c == '\n';
+            });
     }
 
     return ret.str();

lib/settings.h

@@ -372,6 +372,9 @@ class CPPCHECKLIB WARN_UNUSED Settings {
     /** @brief Using -E for debugging purposes */
     bool preprocessOnly{};
 
+    /** @brief Keep comments in preprocessed output */
+    bool keepComments{};
+
     /** @brief Is --quiet given? */
     bool quiet{};
 

man/cppcheck.1.xml

@@ -293,6 +293,22 @@ Example: -DDEBUG=1 -D__cplusplus</para>
 Example: '-UDEBUG'</para>
         </listitem>
       </varlistentry>
+      <varlistentry>
+        <term>
+          <option>-E</option>
+        </term>
+        <listitem>
+          <para>Print preprocessor output on stdout and don't do any further processing.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term>
+          <option>-CC</option>
+        </term>
+        <listitem>
+          <para>Do not remove comments during preprocessing (requires -E).</para>
+        </listitem>
+      </varlistentry>
       <varlistentry>
         <term>
           <option>--disable=&lt;id&gt;</option>

test/testcmdlineparser.cpp

@@ -550,6 +550,8 @@ class TestCmdlineParser : public TestFixture {
         TEST_CASE(reportTypeMisraCpp2023);
         TEST_CASE(invalidReportType);
         TEST_CASE(defaultReportType);
+        TEST_CASE(keepComments);
+        TEST_CASE(keepCommentsNoDashE);
     }
 
     void nooptions() {
@@ -3831,6 +3833,20 @@ class TestCmdlineParser : public TestFixture {
         ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parseFromArgs(argv));
         ASSERT_EQUALS_ENUM(ReportType::normal, settings->reportType);
     }
+
+    void keepComments() {
+        REDIRECT;
+        const char *const argv[] = { "cppcheck", "-E", "-CC", "file.cpp" };
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parseFromArgs(argv));
+        ASSERT(settings->keepComments);
+    }
+
+    void keepCommentsNoDashE() {
+        REDIRECT;
+        const char *const argv[] = { "cppcheck", "-CC", "file.cpp" };
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Fail, parseFromArgs(argv));
+        ASSERT_EQUALS("cppcheck: error: -CC may only be used on conjunciton with -E\n", logger->str());
+    }
 };
 
 REGISTER_TEST(TestCmdlineParser)

test/testpreprocessor.cpp

@@ -374,6 +374,8 @@ class TestPreprocessor : public TestFixture {
         TEST_CASE(testMissingIncludeCheckConfig);
 
         TEST_CASE(testLazyInclude);
+        TEST_CASE(testKeepComments);
+        TEST_CASE(testKeepCommentsMultiline);
 
         TEST_CASE(hasInclude);
 
@@ -3092,6 +3094,52 @@ class TestPreprocessor : public TestFixture {
         ASSERT_EQUALS(1, cache.size());
     }
 
+    void testKeepComments() {
+        const char *code = "#include \"header.h\"\n"
+                           "// source file comment\n"
+                           "/* source file comment */\n";
+        std::vector<std::string> files;
+        simplecpp::TokenList tokens(code, files, "test.c");
+
+        ScopedFile header("header.h",
+                          "// header comment\n"
+                          "/* header comment */\n");
+
+        Settings settings;
+        settings.keepComments = true;
+        Preprocessor preprocessor(tokens, settings, *this, Standards::Language::CPP);
+
+        simplecpp::OutputList outputList;
+        simplecpp::TokenList tokens2 = preprocessor.preprocess("", files, outputList);
+        std::string out = tokens2.stringify();
+
+        const char *expected = "\n"
+                               "#line 1 \"header.h\"\n"
+                               "// header comment\n"
+                               "/* header comment */\n"
+                               "#line 2 \"test.c\"\n"
+                               "// source file comment\n"
+                               "/* source file comment */";
+        ASSERT_EQUALS(expected, out);
+    }
+
+    void testKeepCommentsMultiline() {
+        const char *code = "/* multi...\n"
+                           "   ...line */\n"
+                           "int x;\n";
+        std::vector<std::string> files;
+        simplecpp::TokenList tokens(code, files, "test.c");
+
+        Settings settings;
+        settings.keepComments = true;
+        Preprocessor preprocessor(tokens, settings, *this, Standards::Language::C);
+
+        const char *expected = "/* multi...\n"
+                               "   ...line */\n"
+                               "int x ;";
+        ASSERT_EQUALS(expected, preprocessor.getcode("", files, false));
+    }
+
     void hasInclude() {
         const char code[] = "#if __has_include(<directory/non-existent-header.h>)\n123\n#endif\n";
         Settings settings;