129 lines
5.3 KiB
C++
129 lines
5.3 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2015 Daniel Marjamäki and Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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// You should not write statements with side effects in assert()
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//---------------------------------------------------------------------------
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#include "checkassert.h"
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#include "symboldatabase.h"
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckAssert instance;
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}
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void CheckAssert::assertWithSideEffects()
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{
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if (!_settings->isEnabled("warning"))
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return;
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for (const Token* tok = _tokenizer->list.front(); tok; tok = tok->next()) {
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if (!Token::simpleMatch(tok, "assert ("))
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continue;
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const Token *endTok = tok->next()->link();
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for (const Token* tmp = tok->next(); tmp != endTok; tmp = tmp->next()) {
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checkVariableAssignment(tmp);
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if (tmp->type() == Token::eFunction) {
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const Function* f = tmp->function();
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if (f->nestedIn->isClassOrStruct() && !f->isStatic() && !f->isConst())
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sideEffectInAssertError(tmp, f->name()); // Non-const member function called
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else {
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const Scope* scope = f->functionScope;
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if (!scope) continue;
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for (const Token *tok2 = scope->classStart; tok2 != scope->classEnd; tok2 = tok2->next()) {
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if (tok2->type() != Token::eAssignmentOp && tok2->type() != Token::eIncDecOp)
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continue;
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const Variable* var = tok2->previous()->variable();
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if (!var || var->isLocal() || (var->isArgument() && !var->isReference() && !var->isPointer()))
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continue; // See ticket #4937. Assigning function arguments not passed by reference is ok.
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if (var->isArgument() && var->isPointer() && tok2->strAt(-2) != "*")
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continue; // Pointers need to be dereferenced, otherwise there is no error
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bool noReturnInScope = true;
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for (const Token *rt = scope->classStart; rt != scope->classEnd; rt = rt->next()) {
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if (rt->str() != "return") continue; // find all return statements
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if (inSameScope(rt, tok2)) {
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noReturnInScope = false;
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break;
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}
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}
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if (noReturnInScope) continue;
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sideEffectInAssertError(tmp, f->name());
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break;
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}
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}
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}
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}
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tok = endTok;
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}
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}
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//---------------------------------------------------------------------------
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void CheckAssert::sideEffectInAssertError(const Token *tok, const std::string& functionName)
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{
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reportError(tok, Severity::warning,
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"assertWithSideEffect", "Assert statement calls a function which may have desired side effects: '" + functionName + "'.\n"
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"Non-pure function: '" + functionName + "' is called inside assert statement. "
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"Assert statements are removed from release builds so the code inside "
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"assert statement is not executed. If the code is needed also in release "
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"builds, this is a bug.");
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}
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void CheckAssert::assignmentInAssertError(const Token *tok, const std::string& varname)
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{
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reportError(tok, Severity::warning,
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"assignmentInAssert", "Assert statement modifies '" + varname + "'.\n"
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"Variable '" + varname + "' is modified insert assert statement. "
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"Assert statements are removed from release builds so the code inside "
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"assert statement is not executed. If the code is needed also in release "
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"builds, this is a bug.");
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}
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// checks if side effects happen on the variable prior to tmp
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void CheckAssert::checkVariableAssignment(const Token* assignTok)
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{
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const Variable* v = assignTok->previous()->variable();
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if (!v) return;
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// assignment
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if (assignTok->isAssignmentOp() || assignTok->type() == Token::eIncDecOp) {
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if (v->isConst()) return;
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assignmentInAssertError(assignTok, v->name());
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}
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// TODO: function calls on v
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}
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bool CheckAssert::inSameScope(const Token* returnTok, const Token* assignTok)
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{
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// TODO: even if a return is in the same scope, the assignment might not affect it.
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return returnTok->scope() == assignTok->scope();
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}
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