Fixed #5697 (Check for throw in __attribute__((nothrow)) function)

lib/checkexceptionsafety.cpp

@@ -178,44 +178,48 @@ void CheckExceptionSafety::checkCatchExceptionByValue()
 }
 
 
-//--------------------------------------------------------------------------
+static const Token * functionThrowsRecursive(const Function * function, std::set<const Function *> & recursive)
-//    void func() noexcept { throw x; }
-//--------------------------------------------------------------------------
-void CheckExceptionSafety::noexceptThrows()
 {
-    const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
+    // check for recursion and bail if found
+    if (recursive.find(function) != recursive.end())
+        return nullptr;
 
-    const std::size_t functions = symbolDatabase->functionScopes.size();
+    for (const Token *tok = function->functionScope->classStart->next();
-    for (std::size_t i = 0; i < functions; ++i) {
+         tok != function->functionScope->classEnd; tok = tok->next()) {
-        const Scope * scope = symbolDatabase->functionScopes[i];
-        // only check noexcept functions
-        if (scope->function && scope->function->isNoExcept &&
-            (!scope->function->noexceptArg || scope->function->noexceptArg->str() == "true")) {
-            for (const Token *tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
         if (tok->str() == "try") {
+            // just bail for now
             break;
-                } else if (tok->str() == "throw") {
+        }
-                    noexceptThrowError(tok);
+        if (tok->str() == "throw") {
-                    break;
+            return tok;
         } else if (tok->function()) {
             const Function * called = tok->function();
             // check if called function has an exception specification
             if (called->isThrow && called->throwArg) {
-                        noexceptThrowError(tok);
+                return tok;
-                        break;
             } else if (called->isNoExcept && called->noexceptArg &&
                        called->noexceptArg->str() != "true") {
-                        noexceptThrowError(tok);
+                return tok;
-                        break;
+            } else if (functionThrowsRecursive(called, recursive)) {
-                    }
+                return tok;
-                }
-            }
             }
         }
     }
 
+    return nullptr;
+}
+
+static const Token * functionThrows(const Function * function)
+{
+    std::set<const Function *>  recursive;
+
+    return functionThrowsRecursive(function, recursive);
+}
+
 //--------------------------------------------------------------------------
+//    void func() noexcept { throw x; }
 //    void func() throw() { throw x; }
+//    void func() __attribute__((nothrow)); void func() { throw x; }
 //--------------------------------------------------------------------------
 void CheckExceptionSafety::nothrowThrows()
 {
@@ -224,27 +228,27 @@ void CheckExceptionSafety::nothrowThrows()
     const std::size_t functions = symbolDatabase->functionScopes.size();
     for (std::size_t i = 0; i < functions; ++i) {
         const Scope * scope = symbolDatabase->functionScopes[i];
-        // only check throw() functions
+
-        if (scope->function && scope->function->isThrow && !scope->function->throwArg) {
+        // check noexcept functions
-            for (const Token *tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
+        if (scope->function && scope->function->isNoExcept &&
-                if (tok->str() == "try") {
+            (!scope->function->noexceptArg || scope->function->noexceptArg->str() == "true")) {
-                    break;
+            const Token *throws = functionThrows(scope->function);
-                } else if (tok->str() == "throw") {
+            if (throws)
-                    nothrowThrowError(tok);
+                noexceptThrowError(throws);
-                    break;
-                } else if (tok->function()) {
-                    const Function * called = tok->function();
-                    // check if called function has an exception specification
-                    if (called->isThrow && called->throwArg) {
-                        nothrowThrowError(tok);
-                        break;
-                    } else if (called->isNoExcept && called->noexceptArg &&
-                               called->noexceptArg->str() != "true") {
-                        nothrowThrowError(tok);
-                        break;
-                    }
         }
+
+        // check throw() functions
+        else if (scope->function && scope->function->isThrow && !scope->function->throwArg) {
+            const Token *throws = functionThrows(scope->function);
+            if (throws)
+                nothrowThrowError(throws);
         }
+
+        // check __attribute__((nothrow)) functions
+        else if (scope->function && scope->function->isAttributeNothrow()) {
+            const Token *throws = functionThrows(scope->function);
+            if (throws)
+                nothrowAttributeThrowError(throws);
         }
     }
 }

lib/checkexceptionsafety.h

@@ -61,7 +61,6 @@ public:
         checkExceptionSafety.deallocThrow();
         checkExceptionSafety.checkRethrowCopy();
         checkExceptionSafety.checkCatchExceptionByValue();
-        checkExceptionSafety.noexceptThrows();
         checkExceptionSafety.nothrowThrows();
         checkExceptionSafety.unhandledExceptionSpecification();
     }
@@ -78,10 +77,7 @@ public:
     /** @brief %Check for exceptions that are caught by value instead of by reference */
     void checkCatchExceptionByValue();
 
-    /** @brief %Check for noexcept functions that throw */
+    /** @brief %Check for functions that throw that shouldn't */
-    void noexceptThrows();
-
-    /** @brief %Check for throw() functions that throw */
     void nothrowThrows();
 
     /** @brief %Check for unhandled exception specification */
@@ -122,6 +118,11 @@ private:
         reportError(tok, Severity::error, "exceptThrowInNoThrowFunction", "Exception thrown in throw() function.");
     }
 
+    /** Don't throw exceptions in __attribute__((nothrow))  functions */
+    void nothrowAttributeThrowError(const Token * const tok) {
+        reportError(tok, Severity::error, "exceptThrowInAttributeNoThrowFunction", "Exception thrown in __attribute__((nothrow)) function.");
+    }
+
     /** Missing exception specification */
     void unhandledExceptionSpecificationError(const Token * const tok1, const Token * const tok2, const std::string & funcname) {
         std::string str1(tok1 ? tok1->str() : "foo");
@@ -143,6 +144,7 @@ private:
         c.catchExceptionByValueError(0);
         c.noexceptThrowError(0);
         c.nothrowThrowError(0);
+        c.nothrowAttributeThrowError(0);
         c.unhandledExceptionSpecificationError(0, 0, "funcname");
     }
 
@@ -160,6 +162,7 @@ private:
                "* Exception caught by value instead of by reference\n"
                "* Throwing exception in noexcept function\n"
                "* Throwing exception in nothrow() function\n"
+               "* Throwing exception in __attribute__((nothrow)) function\n"
                "* Unhandled exception specification when calling function foo()\n";
     }
 };

lib/symboldatabase.cpp

@@ -657,6 +657,7 @@ SymbolDatabase::SymbolDatabase(const Tokenizer *tokenizer, const Settings *setti
                         // regular function
                         else {
                             Function* function = addGlobalFunction(scope, tok, argStart, funcStart);
+
                             if (!function)
                                 _tokenizer->syntaxError(tok);
 
@@ -1363,6 +1364,7 @@ Function* SymbolDatabase::addGlobalFunction(Scope*& scope, const Token*& tok, co
             const_cast<Token *>(tok)->isAttributeDestructor(i->tokenDef->isAttributeDestructor());
             const_cast<Token *>(tok)->isAttributePure(i->tokenDef->isAttributePure());
             const_cast<Token *>(tok)->isAttributeConst(i->tokenDef->isAttributeConst());
+            const_cast<Token *>(tok)->isAttributeNothrow(i->tokenDef->isAttributeNothrow());
             break;
         }
     }
@@ -1911,6 +1913,9 @@ void SymbolDatabase::printOut(const char *title) const
             std::cout << "        isNoExcept: " << (func->isNoExcept ? "true" : "false") << std::endl;
             std::cout << "        isThrow: " << (func->isThrow ? "true" : "false") << std::endl;
             std::cout << "        isOperator: " << (func->isOperator ? "true" : "false") << std::endl;
+            std::cerr << "        isAttributeConst: " << (func->isAttributeConst() ? "true" : "false") << std::endl;
+            std::cerr << "        isAttributePure: " << (func->isAttributePure() ? "true" : "false") << std::endl;
+            std::cerr << "        isAttributeNothrow: " << (func->isAttributeNothrow() ? "true" : "false") << std::endl;
             std::cout << "        noexceptArg: " << (func->noexceptArg ? func->noexceptArg->str() : "none") << std::endl;
             std::cout << "        throwArg: " << (func->throwArg ? func->throwArg->str() : "none") << std::endl;
             std::cout << "        tokenDef: " << func->tokenDef->str() << " " <<_tokenizer->list.fileLine(func->tokenDef) << std::endl;

lib/symboldatabase.h

@@ -590,6 +590,9 @@ public:
     bool isAttributeConst() const {
         return tokenDef->isAttributeConst();
     }
+    bool isAttributeNothrow() const {
+        return tokenDef->isAttributeNothrow();
+    }
 
     const Token *tokenDef; // function name token in class definition
     const Token *argDef;   // function argument start '(' in class definition

lib/token.cpp

@@ -56,6 +56,7 @@ Token::Token(Token **t) :
     _isAttributeUnused(false),
     _isAttributePure(false),
     _isAttributeConst(false),
+    _isAttributeNothrow(false),
     _astOperand1(nullptr),
     _astOperand2(nullptr),
     _astParent(nullptr)
@@ -196,6 +197,7 @@ void Token::deleteThis()
         _isAttributeUnused = _next->_isAttributeUnused;
         _isAttributePure = _next->_isAttributePure;
         _isAttributeConst = _next->_isAttributeConst;
+        _isAttributeNothrow = _next->_isAttributeNothrow;
         _varId = _next->_varId;
         _fileIndex = _next->_fileIndex;
         _linenr = _next->_linenr;
@@ -223,6 +225,7 @@ void Token::deleteThis()
         _isAttributeUnused = _previous->_isAttributeUnused;
         _isAttributePure = _previous->_isAttributePure;
         _isAttributeConst = _previous->_isAttributeConst;
+        _isAttributeNothrow = _previous->_isAttributeNothrow;
         _varId = _previous->_varId;
         _fileIndex = _previous->_fileIndex;
         _linenr = _previous->_linenr;

lib/token.h

@@ -312,6 +312,12 @@ public:
     void isAttributeConst(bool value) {
         _isAttributeConst = value;
     }
+    bool isAttributeNothrow() const {
+        return _isAttributeNothrow;
+    }
+    void isAttributeNothrow(bool value) {
+        _isAttributeNothrow = value;
+    }
 
     static const Token *findsimplematch(const Token *tok, const char pattern[]);
     static const Token *findsimplematch(const Token *tok, const char pattern[], const Token *end);
@@ -695,6 +701,7 @@ private:
     bool _isAttributeUnused;       // __attribute__((unused))
     bool _isAttributePure;         // __attribute__((pure))
     bool _isAttributeConst;        // __attribute__((const))
+    bool _isAttributeNothrow;      // __attribute__((nothrow))
 
     /** Updates internal property cache like _isName or _isBoolean.
         Called after any _str() modification. */

lib/tokenize.cpp

@@ -120,6 +120,7 @@ Token *Tokenizer::copyTokens(Token *dest, const Token *first, const Token *last,
         tok2->isAttributeUnused(tok->isAttributeUnused());
         tok2->isAttributePure(tok->isAttributePure());
         tok2->isAttributeConst(tok->isAttributeConst());
+        tok2->isAttributeNothrow(tok->isAttributeNothrow());
         tok2->varId(tok->varId());
 
         // Check for links and fix them up
@@ -9057,7 +9058,7 @@ void Tokenizer::simplifyAttribute()
 {
     for (Token *tok = list.front(); tok; tok = tok->next()) {
         while (Token::Match(tok, "__attribute__|__attribute (") && tok->next()->link() && tok->next()->link()->next()) {
-            if (Token::simpleMatch(tok->tokAt(2), "( constructor")) {
+            if (Token::Match(tok->tokAt(2), "( constructor|__constructor__")) {
                 // prototype for constructor is: void func(void);
                 if (tok->next()->link()->next()->str() == "void") // __attribute__((constructor)) void func() {}
                     tok->next()->link()->next()->next()->isAttributeConstructor(true);
@@ -9067,7 +9068,7 @@ void Tokenizer::simplifyAttribute()
                     tok->next()->link()->next()->isAttributeConstructor(true);
             }
 
-            if (Token::simpleMatch(tok->tokAt(2), "( destructor")) {
+            else if (Token::Match(tok->tokAt(2), "( destructor|__destructor__")) {
                 // prototype for destructor is: void func(void);
                 if (tok->next()->link()->next()->str() == "void") // __attribute__((destructor)) void func() {}
                     tok->next()->link()->next()->next()->isAttributeDestructor(true);
@@ -9077,7 +9078,7 @@ void Tokenizer::simplifyAttribute()
                     tok->next()->link()->next()->isAttributeDestructor(true);
             }
 
-            if (Token::simpleMatch(tok->tokAt(2), "( unused )")) {
+            else if (Token::Match(tok->tokAt(2), "( unused|__unused__ )")) {
                 // check if after variable name
                 if (Token::Match(tok->next()->link()->next(), ";|=")) {
                     if (Token::Match(tok->previous(), "%type%"))
@@ -9089,26 +9090,57 @@ void Tokenizer::simplifyAttribute()
                     tok->next()->link()->next()->isAttributeUnused(true);
             }
 
-            if (Token::simpleMatch(tok->tokAt(2), "( pure )")) {
+            else if (Token::Match(tok->tokAt(2), "( pure|__pure__ )")) {
                 // type func(...) __attribute__((pure));
                 if (tok->previous() && tok->previous()->link() && Token::Match(tok->previous()->link()->previous(), "%var% ("))
                     tok->previous()->link()->previous()->isAttributePure(true);
 
                 // type __attribute__((pure)) func() { }
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2)->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->linkAt(2)->next()->isAttributePure(true);
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->next()->isAttributePure(true);
                 else if (Token::Match(tok->next()->link(), ") %var% ("))
                     tok->next()->link()->next()->isAttributePure(true);
             }
 
-            if (Token::simpleMatch(tok->tokAt(2), "( const )")) {
+            else if (Token::Match(tok->tokAt(2), "( const|__const__ )")) {
                 // type func(...) __attribute__((const));
                 if (tok->previous() && tok->previous()->link() && Token::Match(tok->previous()->link()->previous(), "%var% ("))
                     tok->previous()->link()->previous()->isAttributeConst(true);
 
                 // type __attribute__((const)) func() { }
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2)->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->linkAt(2)->next()->isAttributeConst(true);
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->next()->isAttributeConst(true);
                 else if (Token::Match(tok->next()->link(), ") %var% ("))
                     tok->next()->link()->next()->isAttributeConst(true);
             }
 
+            else if (Token::Match(tok->tokAt(2), "( nothrow|__nothrow__")) {
+                // type func(...) __attribute__((nothrow));
+                if (tok->previous() && tok->previous()->link() && Token::Match(tok->previous()->link()->previous(), "%var% ("))
+                    tok->previous()->link()->previous()->isAttributeNothrow(true);
+
+                // type __attribute__((nothrow)) func() { }
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2)->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->linkAt(2)->next()->isAttributeNothrow(true);
+                else if (Token::Match(tok->next()->link(), ") __attribute__|__attribute (") &&
+                         Token::Match(tok->next()->link()->linkAt(2), ") %var% ("))
+                    tok->next()->link()->linkAt(2)->next()->isAttributeNothrow(true);
+                else if (Token::Match(tok->next()->link(), ") %var% ("))
+                    tok->next()->link()->next()->isAttributeNothrow(true);
+            }
+
             Token::eraseTokens(tok, tok->next()->link()->next());
             tok->deleteThis();
         }

lib/tokenlist.cpp

@@ -153,6 +153,7 @@ void TokenList::addtoken(const Token * tok, const unsigned int lineno, const uns
     _back->isAttributeUnused(tok->isAttributeUnused());
     _back->isAttributePure(tok->isAttributePure());
     _back->isAttributeConst(tok->isAttributeConst());
+    _back->isAttributeNothrow(tok->isAttributeNothrow());
 }
 //---------------------------------------------------------------------------
 // InsertTokens - Copy and insert tokens
@@ -187,6 +188,7 @@ void TokenList::insertTokens(Token *dest, const Token *src, unsigned int n)
         dest->isAttributeUnused(src->isAttributeUnused());
         dest->isAttributePure(src->isAttributePure());
         dest->isAttributeConst(src->isAttributeConst());
+        dest->isAttributeNothrow(src->isAttributeNothrow());
         src  = src->next();
         --n;
     }

test/testexceptionsafety.cpp

@@ -356,6 +356,19 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:1]: (warning) Unhandled exception specification when calling function myThrowingFoo().\n", errout.str());
     }
+
+    void nothrowAttributeThrow() {
+        check("void func1() throw(int) { throw 1; }\n"
+              "void func2() __attribute((nothrow)); void func1() { throw 1; }\n"
+              "void func3() __attribute((nothrow)); void func1() { func1(); }\n");
+        ASSERT_EQUALS("[test.cpp:2]: (error) Exception thrown in __attribute__((nothrow)) function.\n"
+                      "[test.cpp:3]: (error) Exception thrown in __attribute__((nothrow)) function.\n", errout.str());
+
+        // avoid false positives
+        check("const char *func() __attribute((nothrow)); void func1() { return 0; }\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
 };
 
 REGISTER_TEST(TestExceptionSafety)

test/testsymboldatabase.cpp

@@ -234,6 +234,8 @@ private:
         TEST_CASE(noexceptFunction2);
         TEST_CASE(noexceptFunction3);
         TEST_CASE(noexceptFunction4);
+
+        TEST_CASE(nothrowAttributeFunction);
     }
 
     void array() const {
@@ -2144,6 +2146,20 @@ private:
         }
     }
 
+    void nothrowAttributeFunction() {
+        GET_SYMBOL_DB("void func() __attribute__((nothrow));\n"
+                      "void func() { }\n");
+        ASSERT_EQUALS("", errout.str());
+        ASSERT_EQUALS(true,  db != nullptr); // not null
+
+        if (db) {
+            const Function *func = findFunctionByName("func", &db->scopeList.front());
+            ASSERT_EQUALS(true, func != nullptr);
+            if (func)
+                ASSERT_EQUALS(true, func->isAttributeNothrow());
+        }
+    }
+
 };
 
 REGISTER_TEST(TestSymbolDatabase)

test/testtokenize.cpp

@@ -444,6 +444,8 @@ private:
 
         TEST_CASE(removedeclspec);
         TEST_CASE(removeattribute);
+        TEST_CASE(functionAttributeBefore);
+        TEST_CASE(functionAttributeAfter);
         TEST_CASE(cpp0xtemplate1);
         TEST_CASE(cpp0xtemplate2);
         TEST_CASE(cpp0xtemplate3);
@@ -7089,6 +7091,66 @@ private:
         ASSERT_EQUALS("int vecint ;", tokenizeAndStringify("int __attribute((mode(SI))) __attribute((vector_size (16))) vecint;"));
     }
 
+    void functionAttributeBefore() {
+        const char code[] = "void __attribute__((pure)) __attribute__((nothrow)) __attribute__((const)) func1();\n"
+                            "void __attribute__((__pure__)) __attribute__((__nothrow__)) __attribute__((__const__)) func2();\n"
+                            "void __attribute__((nothrow)) __attribute__((pure)) __attribute__((const)) func3();\n"
+                            "void __attribute__((__nothrow__)) __attribute__((__pure__)) __attribute__((__const__)) func4();";
+        const char expected[] = "void func1 ( ) ; void func2 ( ) ; void func3 ( ) ; void func4 ( ) ;";
+
+        errout.str("");
+
+        Settings settings;
+
+        // tokenize..
+        Tokenizer tokenizer(&settings, this);
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+
+        // Expected result..
+        ASSERT_EQUALS(expected, tokenizer.tokens()->stringifyList(0, false));
+
+        const Token * func1 = Token::findsimplematch(tokenizer.tokens(), "func1");
+        const Token * func2 = Token::findsimplematch(tokenizer.tokens(), "func2");
+        const Token * func3 = Token::findsimplematch(tokenizer.tokens(), "func3");
+        const Token * func4 = Token::findsimplematch(tokenizer.tokens(), "func4");
+
+        ASSERT(func1 && func1->isAttributePure() && func1->isAttributeNothrow() && func1->isAttributeConst());
+        ASSERT(func2 && func2->isAttributePure() && func2->isAttributeNothrow() && func2->isAttributeConst());
+        ASSERT(func3 && func3->isAttributePure() && func3->isAttributeNothrow() && func3->isAttributeConst());
+        ASSERT(func4 && func4->isAttributePure() && func4->isAttributeNothrow() && func4->isAttributeConst());
+    }
+
+    void functionAttributeAfter() {
+        const char code[] = "void func1() __attribute__((pure)) __attribute__((nothrow)) __attribute__((const));\n"
+                            "void func2() __attribute__((__pure__)) __attribute__((__nothrow__)) __attribute__((__const__));\n"
+                            "void func3() __attribute__((nothrow)) __attribute__((pure)) __attribute__((const));\n"
+                            "void func4() __attribute__((__nothrow__)) __attribute__((__pure__)) __attribute__((__const__));";
+        const char expected[] = "void func1 ( ) ; void func2 ( ) ; void func3 ( ) ; void func4 ( ) ;";
+
+        errout.str("");
+
+        Settings settings;
+
+        // tokenize..
+        Tokenizer tokenizer(&settings, this);
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+
+        // Expected result..
+        ASSERT_EQUALS(expected, tokenizer.tokens()->stringifyList(0, false));
+
+        const Token * func1 = Token::findsimplematch(tokenizer.tokens(), "func1");
+        const Token * func2 = Token::findsimplematch(tokenizer.tokens(), "func2");
+        const Token * func3 = Token::findsimplematch(tokenizer.tokens(), "func3");
+        const Token * func4 = Token::findsimplematch(tokenizer.tokens(), "func4");
+
+        ASSERT(func1 && func1->isAttributePure() && func1->isAttributeNothrow() && func1->isAttributeConst());
+        ASSERT(func2 && func2->isAttributePure() && func2->isAttributeNothrow() && func2->isAttributeConst());
+        ASSERT(func3 && func3->isAttributePure() && func3->isAttributeNothrow() && func3->isAttributeConst());
+        ASSERT(func4 && func4->isAttributePure() && func4->isAttributeNothrow() && func4->isAttributeConst());
+    }
+
     void cpp0xtemplate1() {
         const char *code = "template <class T>\n"
                            "void fn2 (T t = []{return 1;}())\n"