updated CI to Clang 21

.clang-tidy

@@ -50,10 +50,12 @@ Checks: >
         -modernize-type-traits,
         -modernize-use-designated-initializers,
         -modernize-use-nodiscard,
+        -modernize-use-scoped-lock,
         -modernize-use-trailing-return-type,
         -performance-avoid-endl,
         -performance-inefficient-string-concatenation,
         -performance-no-automatic-move,
+        -portability-avoid-pragma-once,
         -portability-simd-intrinsics,
         -portability-std-allocator-const,
         -readability-avoid-nested-conditional-operator,
@@ -68,7 +70,8 @@ Checks: >
         -readability-isolate-declaration,
         -readability-magic-numbers,
         -readability-suspicious-call-argument,
-        -readability-uppercase-literal-suffix
+        -readability-uppercase-literal-suffix,
+        -readability-use-concise-preprocessor-directives
 WarningsAsErrors: '*'
 HeaderFilterRegex: '(cli|gui|frontend|lib|oss-fuzz|test|triage)\/[a-z_]+\.h'
 ExcludeHeaderFilterRegex: 'ui_.*.h'
@@ -77,3 +80,5 @@ CheckOptions:
     value:           '1'
   - key:             readability-simplify-boolean-expr.SimplifyDeMorgan
     value:           '0'
+  - key:             modernize-use-trailing-return-type.TransformFunctions
+    value:           false

.github/workflows/asan.yml

@@ -53,7 +53,7 @@ jobs:
           sudo apt-get purge --auto-remove llvm python3-lldb-14 llvm-14
           wget https://apt.llvm.org/llvm.sh
           chmod +x llvm.sh
-          sudo ./llvm.sh 20
+          sudo ./llvm.sh 21
 
       - name: Install Qt ${{ env.QT_VERSION }}
         uses: jurplel/install-qt-action@v4
@@ -76,8 +76,8 @@ jobs:
         run: |
           cmake -S . -B cmake.output -DCMAKE_BUILD_TYPE=RelWithDebInfo -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DUSE_QT6=On -DWITH_QCHART=On -DBUILD_TRIAGE=On -DUSE_MATCHCOMPILER=Verify -DANALYZE_ADDRESS=On -DENABLE_CHECK_INTERNAL=On -DUSE_BOOST=On -DCPPCHK_GLIBCXX_DEBUG=Off -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DDISABLE_DMAKE=On -DFILESDIR= -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
         env:
-          CC: clang-20
-          CXX: clang++-20
+          CC: clang-21
+          CXX: clang++-21
 
       - name: Build cppcheck
         run: |

.github/workflows/clang-tidy.yml

@@ -43,8 +43,8 @@ jobs:
           sudo apt-get purge --auto-remove llvm python3-lldb-14 llvm-14
           wget https://apt.llvm.org/llvm.sh
           chmod +x llvm.sh
-          sudo ./llvm.sh 20
-          sudo apt-get install -y clang-tidy-20
+          sudo ./llvm.sh 21
+          sudo apt-get install -y clang-tidy-21
 
       - name: Install Qt ${{ env.QT_VERSION }}
         uses: jurplel/install-qt-action@v4
@@ -57,14 +57,14 @@ jobs:
 
       - name: Verify clang-tidy configuration
         run: |
-          clang-tidy-20 --verify-config
+          clang-tidy-21 --verify-config
 
       - name: Prepare CMake
         run: |
           cmake -S . -B cmake.output -G "Unix Makefiles" -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DWITH_QCHART=On -DBUILD_TRIAGE=On -DENABLE_CHECK_INTERNAL=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DCPPCHK_GLIBCXX_DEBUG=Off -DWARNINGS_ARE_ERRORS=On
         env:
-          CC: clang-20
-          CXX: clang++-20
+          CC: clang-21
+          CXX: clang++-21
 
       - name: Prepare CMake dependencies
         run: |

.github/workflows/iwyu.yml

@@ -215,13 +215,13 @@ jobs:
           sudo apt-get purge --auto-remove llvm python3-lldb-14 llvm-14
           wget https://apt.llvm.org/llvm.sh
           chmod +x llvm.sh
-          sudo ./llvm.sh 20
-          sudo apt-get install -y clang-tools-20
+          sudo ./llvm.sh 21
+          sudo apt-get install -y clang-tools-21
 
       - name: Install libc++
         if: matrix.stdlib == 'libc++'
         run: |
-          sudo apt-get install -y libc++-20-dev
+          sudo apt-get install -y libc++-21-dev
 
       - name: Install Qt ${{ env.QT_VERSION }}
         uses: jurplel/install-qt-action@v4
@@ -237,8 +237,8 @@ jobs:
           # TODO: why does it build dmake in the next step?
           cmake -S . -B cmake.output -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DWITH_QCHART=On -DBUILD_TRIAGE=On -DENABLE_CHECK_INTERNAL=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCPPCHK_GLIBCXX_DEBUG=Off -DUSE_MATCHCOMPILER=Off -DEXTERNALS_AS_SYSTEM=On -DUSE_LIBCXX=${{ matrix.use_libcxx }}
         env:
-          CC: clang-20
-          CXX: clang++-20
+          CC: clang-21
+          CXX: clang++-21
 
       - name: Prepare CMake dependencies
         run: |
@@ -255,7 +255,7 @@ jobs:
       - name: clang-include-cleaner
         run: |
           # TODO: run multi-threaded
-          find $PWD/cli $PWD/lib $PWD/test $PWD/gui -maxdepth 1 -name "*.cpp" | xargs -t -n 1 clang-include-cleaner-20 --print=changes --extra-arg=-w --extra-arg=-stdlib=${{ matrix.stdlib }} -p cmake.output > clang-include-cleaner.log 2>&1
+          find $PWD/cli $PWD/lib $PWD/test $PWD/gui -maxdepth 1 -name "*.cpp" | xargs -t -n 1 clang-include-cleaner-21 --print=changes --extra-arg=-w --extra-arg=-stdlib=${{ matrix.stdlib }} -p cmake.output > clang-include-cleaner.log 2>&1
 
       - uses: actions/upload-artifact@v4
         if: success() || failure()

.github/workflows/tsan.yml

@@ -53,7 +53,7 @@ jobs:
           sudo apt-get purge --auto-remove llvm python3-lldb-14 llvm-14
           wget https://apt.llvm.org/llvm.sh
           chmod +x llvm.sh
-          sudo ./llvm.sh 20
+          sudo ./llvm.sh 21
 
       - name: Install Qt ${{ env.QT_VERSION }}
         uses: jurplel/install-qt-action@v4
@@ -75,8 +75,8 @@ jobs:
         run: |
           cmake -S . -B cmake.output -DCMAKE_BUILD_TYPE=RelWithDebInfo -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DUSE_QT6=On -DWITH_QCHART=On -DBUILD_TRIAGE=On -DUSE_MATCHCOMPILER=Verify -DANALYZE_THREAD=On -DENABLE_CHECK_INTERNAL=On -DUSE_BOOST=On -DCPPCHK_GLIBCXX_DEBUG=Off -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=Off -DDISABLE_DMAKE=On -DFILESDIR= -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
         env:
-          CC: clang-20
-          CXX: clang++-20
+          CC: clang-21
+          CXX: clang++-21
 
       - name: Build cppcheck
         run: |

.github/workflows/ubsan.yml

@@ -53,7 +53,7 @@ jobs:
           sudo apt-get purge --auto-remove llvm python3-lldb-14 llvm-14
           wget https://apt.llvm.org/llvm.sh
           chmod +x llvm.sh
-          sudo ./llvm.sh 20
+          sudo ./llvm.sh 21
 
       - name: Install Qt ${{ env.QT_VERSION }}
         uses: jurplel/install-qt-action@v4
@@ -76,8 +76,8 @@ jobs:
         run: |
           cmake -S . -B cmake.output -DCMAKE_BUILD_TYPE=RelWithDebInfo -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=On -DUSE_QT6=On -DWITH_QCHART=On -DBUILD_TRIAGE=On -DUSE_MATCHCOMPILER=Verify -DANALYZE_UNDEFINED=On -DENABLE_CHECK_INTERNAL=On -DUSE_BOOST=On -DCPPCHK_GLIBCXX_DEBUG=Off -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DDISABLE_DMAKE=On -DFILESDIR= -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
         env:
-          CC: clang-20
-          CXX: clang++-20
+          CC: clang-21
+          CXX: clang++-21
 
       - name: Build cppcheck
         run: |

clang-tidy.md

@@ -33,7 +33,6 @@ These are coding guidelines we do not follow. Some of the checks might be explic
 
 `readability-braces-around-statements`<br/>
 `readability-isolate-declaration`<br/>
-`modernize-use-trailing-return-type`<br/>
 `readability-uppercase-literal-suffix`<br/>
 `readability-identifier-length`<br/>
 
@@ -112,7 +111,11 @@ Also reports a false positive about templates which deduce the array length: htt
 
 `misc-include-cleaner`<br/>
 
-We run this separately via `clang-include-cleaner` in the `iwyu.yml` workflow as the findings of the include checkers still need to be reviewed manually before applying them. 
+We run this separately via `clang-include-cleaner` in the `iwyu.yml` workflow as the findings of the include checkers still need to be reviewed manually before applying them.
+
+`readability-use-concise-preprocessor-directives`<br/>
+
+Does not improve the readability.
 
 `bugprone-branch-clone`<br/>
 `modernize-return-braced-init-list`<br/>
@@ -126,6 +129,7 @@ We run this separately via `clang-include-cleaner` in the `iwyu.yml` workflow as
 `readability-avoid-nested-conditional-operator`<br/>
 `modernize-use-designated-initializers`<br/>
 `readability-enum-initial-value`<br/>
+`modernize-use-trailing-return-type`<br/>
 
 To be evaluated (need to remove exclusion).
 
@@ -144,9 +148,14 @@ To be evaluated (need to enable explicitly).
 
 `modernize-type-traits`<br/>
 `modernize-use-nodiscard`<br/>
+`modernize-use-scoped-lock`<br/>
 
 These apply to codebases which use later standards then C++11 (C++17 is used when building with Qt6) so we cannot simply apply them.
 
+`portability-avoid-pragma-once`<br/>
+
+We are not interested in this.
+
 ### Disabled for performance reasons
 
 `portability-std-allocator-const`<br/>

cli/processexecutor.cpp

@@ -127,12 +127,12 @@ namespace {
             const ssize_t bytes_written = write(mWpipe, data, to_write);
             if (bytes_written <= 0) {
                 const int err = errno;
-                std::cerr << "#### ThreadExecutor::writeToPipeInternal() error for type " << type << ": " << std::strerror(err) << std::endl;
+                std::cerr << "#### ThreadExecutor::writeToPipeInternal() error for type " << static_cast<unsigned char>(type) << ": " << std::strerror(err) << std::endl;
                 std::exit(EXIT_FAILURE);
             }
             // TODO: write until everything is written
             if (bytes_written != to_write) {
-                std::cerr << "#### ThreadExecutor::writeToPipeInternal() error for type " << type << ": insufficient data written (expected: " << to_write << " / got: " << bytes_written << ")" << std::endl;
+                std::cerr << "#### ThreadExecutor::writeToPipeInternal() error for type " << static_cast<unsigned char>(type) << ": insufficient data written (expected: " << to_write << " / got: " << bytes_written << ")" << std::endl;
                 std::exit(EXIT_FAILURE);
             }
         }

cli/signalhandler.cpp

@@ -58,7 +58,7 @@
 #ifdef __USE_DYNAMIC_STACK_SIZE
 static constexpr size_t MYSTACKSIZE = (16*1024)+32768; // wild guess about a reasonable buffer
 #else
-static constexpr size_t MYSTACKSIZE = 16*1024+SIGSTKSZ; // wild guess about a reasonable buffer
+static constexpr size_t MYSTACKSIZE = (16*1024)+SIGSTKSZ; // wild guess about a reasonable buffer
 #endif
 static char mytstack[MYSTACKSIZE]= {0}; // alternative stack for signal handler
 static bool bStackBelowHeap=false; // lame attempt to locate heap vs. stack address space. See CppCheckExecutor::check_wrapper()

cmake/clang_tidy.cmake

@@ -11,7 +11,7 @@ if(NOT CMAKE_DISABLE_PRECOMPILE_HEADERS)
         message(STATUS "Cannot use non-Clang compiler with clang-tidy when precompiled headers are enabled - skipping 'run-clang-tidy'/'run-clang-tidy-csa' target generation")
     endif()
 else()
-    set(RUN_CLANG_TIDY_NAMES run-clang-tidy run-clang-tidy-20 run-clang-tidy-19 run-clang-tidy-18 run-clang-tidy-17 run-clang-tidy-16 run-clang-tidy-15 run-clang-tidy-14 run-clang-tidy-13 run-clang-tidy-12 run-clang-tidy-11 run-clang-tidy-10 run-clang-tidy-9 run-clang-tidy-8)
+    set(RUN_CLANG_TIDY_NAMES run-clang-tidy run-clang-tidy-21 run-clang-tidy-20 run-clang-tidy-19 run-clang-tidy-18 run-clang-tidy-17 run-clang-tidy-16 run-clang-tidy-15 run-clang-tidy-14 run-clang-tidy-13 run-clang-tidy-12 run-clang-tidy-11 run-clang-tidy-10 run-clang-tidy-9 run-clang-tidy-8)
 endif()
 
 if(RUN_CLANG_TIDY_NAMES)
@@ -32,10 +32,9 @@ if(RUN_CLANG_TIDY_NAMES)
         # clang-analyzer-cplusplus.NewDelete
         # clang-analyzer-core.NullDereference
         # clang-analyzer-unix.Stream
-        # clang-analyzer-optin.cplusplus.UninitializedObject - false positives with unnamed fields - see https://github.com/llvm/llvm-project/issues/132001
         # clang-analyzer-alpha.clone.CloneChecker
         # clang-analyzer-alpha.webkit.* - we are not interested in these
-        set(CLANG_TIDY_CSA_CONFIG "-config={InheritParentConfig: true, Checks: '-*,clang-analyzer-*,-clang-analyzer-core.CallAndMessage,-clang-analyzer-core.NonNullParamChecker,-clang-analyzer-cplusplus.NewDeleteLeaks,-clang-analyzer-cplusplus.NewDelete,-clang-analyzer-core.NullDereference,-clang-analyzer-unix.Stream,-clang-analyzer-optin.cplusplus.UninitializedObject,-clang-analyzer-alpha.clone.CloneChecker,-clang-analyzer-alpha.webkit.*'}")
+        set(CLANG_TIDY_CSA_CONFIG "-config={InheritParentConfig: true, Checks: '-*,clang-analyzer-*,-clang-analyzer-core.CallAndMessage,-clang-analyzer-core.NonNullParamChecker,-clang-analyzer-cplusplus.NewDeleteLeaks,-clang-analyzer-cplusplus.NewDelete,-clang-analyzer-core.NullDereference,-clang-analyzer-unix.Stream,-clang-analyzer-alpha.clone.CloneChecker,-clang-analyzer-alpha.webkit.*'}")
         if (ENABLE_CSA_ALPHA)
             set(CLANG_TIDY_CSA_ALPHA_OPTS "-allow-enabling-alpha-checkers" "-extra-arg=-Xclang" "-extra-arg=-analyzer-config" "-extra-arg=-Xclang" "-extra-arg=aggressive-binary-operation-simplification=true")
         endif()

cmake/compileroptions.cmake

@@ -122,6 +122,7 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     add_compile_options(-Wno-disabled-macro-expansion)
     add_compile_options_safe(-Wno-bitwise-instead-of-logical)
     add_compile_options(-Wno-sign-compare)
+    add_compile_options_safe(-Wno-ms-bitfield-padding) # TODO: fix this
 
     # these cannot be fixed properly without adopting later C++ standards
     add_compile_options_safe(-Wno-unsafe-buffer-usage)
@@ -130,6 +131,7 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 
     # can only be partially addressed
     add_compile_options(-Wno-padded)
+    add_compile_options_safe(-Wno-nrvo)
 
     # no need for C++98 compatibility
     add_compile_options(-Wno-c++98-compat)

gui/cppchecklibrarydata.cpp

@@ -33,12 +33,12 @@
 const unsigned int CppcheckLibraryData::Function::Arg::ANY = ~0U;
 const unsigned int CppcheckLibraryData::Function::Arg::VARIADIC = ~1U;
 
-static std::string unhandledElement(const QXmlStreamReader &xmlReader)
+NORETURN static void unhandledElement(const QXmlStreamReader &xmlReader)
 {
     throw std::runtime_error(QObject::tr("line %1: Unhandled element %2").arg(xmlReader.lineNumber()).arg(xmlReader.name().toString()).toStdString());
 }
 
-static std::string mandatoryAttibuteMissing(const QXmlStreamReader &xmlReader, const QString& attributeName)
+NORETURN static void mandatoryAttibuteMissing(const QXmlStreamReader &xmlReader, const QString& attributeName)
 {
     throw std::runtime_error(QObject::tr("line %1: Mandatory attribute '%2' missing in '%3'")
                              .arg(xmlReader.lineNumber())

gui/mainwindow.cpp

@@ -2244,12 +2244,12 @@ static int getVersion(const QString& nameWithVersion) {
         }
         else if (c == '.') {
             ++dot;
-            ret = ret * 1000 + v;
+            ret = (ret * 1000) + v;
             v = 0;
         } else if (c >= '0' && c <= '9')
-            v = v * 10 + (c.toLatin1() - '0');
+            v = (v * 10) + (c.toLatin1() - '0');
     }
-    ret = ret * 1000 + v;
+    ret = (ret * 1000) + v;
     while (dot < 2) {
         ++dot;
         ret *= 1000;

lib/clangimport.cpp

@@ -997,7 +997,7 @@ Token *clangimport::AstNode::createTokens(TokenList &tokenList)
             --addrIndex;
         const std::string addr = mExtTokens[addrIndex];
         std::string name = unquote(getSpelling());
-        Token *reftok = addtoken(tokenList, name.empty() ? "<NoName>" : std::move(name));
+        Token *reftok = addtoken(tokenList, name.empty() ? "<NoName>" : name);
         mData->ref(addr, reftok);
         return reftok;
     }

lib/valueflow.cpp

@@ -547,7 +547,7 @@ size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings &settings, Accur
                 if (currentBitfieldAlloc == 0) {
                     bits = n * charBit;
                 } else {
-                    bits = currentBitfieldAlloc * charBit - currentBitCount;
+                    bits = (currentBitfieldAlloc * charBit) - currentBitCount;
                 }
             }
             if (bits > 0) {
@@ -570,7 +570,7 @@ size_t ValueFlow::getSizeOf(const ValueType &vt, const Settings &settings, Accur
             n *= dim;
             size_t padding = (a - (total % a)) % a;
             if (currentBitCount > 0) {
-                bool fitsInBitfield = currentBitCount + n * charBit <= currentBitfieldAlloc * charBit;
+                bool fitsInBitfield = currentBitCount + (n * charBit) <= currentBitfieldAlloc * charBit;
                 bool isAligned = currentBitCount % (charBit * a) == 0;
                 if (vt2.isIntegral() && fitsInBitfield && isAligned) {
                     currentBitCount += charBit * n;
@@ -5857,7 +5857,7 @@ static void valueFlowSubFunction(const TokenList& tokenlist,
                     v.errorPath.emplace_back(argtok,
                                              "Calling function '" + calledFunction->name() + "', " + nr + " argument '" +
                                              argtok->expressionString() + "' value is " + v.infoString());
-                    v.path = 256 * v.path + id % 256;
+                    v.path = (256 * v.path) + (id % 256);
                     // Change scope of lifetime values
                     if (v.isLifetimeValue())
                         v.lifetimeScope = ValueFlow::Value::LifetimeScope::SubFunction;

test/fixture.h

@@ -79,8 +79,10 @@ class TestFixture : public ErrorLogger {
     void assertEquals(const char* const filename, const unsigned int linenr, const T& expected, const T& actual, const std::string& msg = "") const {
         if (expected != actual) {
             std::ostringstream expectedStr;
+            // NOLINTNEXTLINE(bugprone-unintended-char-ostream-output) - chars being treated as integers is acceptable here
             expectedStr << expected;
             std::ostringstream actualStr;
+            // NOLINTNEXTLINE(bugprone-unintended-char-ostream-output) - chars being treated as integers is acceptable here
             actualStr << actual;
 
             assertFailure(filename, linenr, expectedStr.str(), actualStr.str(), msg);

test/testexecutor.cpp

@@ -38,7 +38,7 @@ class DummyExecutor : public Executor
         : Executor(files, fileSettings, settings, suppressions, errorLogger)
     {}
 
-    unsigned int check() override
+    NORETURN unsigned int check() override
     {
         throw std::runtime_error("not implemented");
     }