walkero
/
cppcheck
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

Fixed #5866 (False negative: useless condition or null pointer dereference (null object after while loop, method))

This commit is contained in:
Daniel Marjamäki 2014-08-16 18:32:25 +02:00
parent 76510e0006
commit 65f10edcb6
3 changed files with 63 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/tokenize.cpp
View File

@ -2202,6 +2202,8 @@ void Tokenizer::simplifyLabelsCaseDefault()
if (Token::Match(tok->next(),"[:{};]"))
break;
}
if (!tok)
break;
if (tok->str() != "case" && tok->next() && tok->next()->str() == ":") {
tok = tok->next();
if (tok->next()->str() != ";")

29
lib/valueflow.cpp
View File

@ -704,6 +704,17 @@ static bool valueFlowForward(Token * const startToken,
// TODO: don't check noreturn scopes
if (read && (number_of_if > 0U || Token::findmatch(tok2, "%varid%", start, varid))) {
// Set values in condition
const Token * const condend = tok2->linkAt(1);
for (Token *condtok = tok2; condtok != condend; condtok = condtok->next()) {
if (condtok->varId() == varid) {
std::list<ValueFlow::Value>::const_iterator it;
for (it = values.begin(); it != values.end(); ++it)
setTokenValue(condtok, *it);
}
if (Token::Match(condtok, "%oror%|&&"))
break;
}
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->nameToken()->str() + " is assigned in conditional code");
return false;
@ -896,13 +907,15 @@ static void valueFlowAfterCondition(TokenList *tokenlist, ErrorLogger *errorLogg
if (Token::Match(tok,"==|!=|>=|<=")) {
if (!tok->astOperand1() || !tok->astOperand2())
continue;
if (tok->astOperand1()->isName()) {
vartok = tok->astOperand1();
numtok = tok->astOperand2();
} else {
vartok = tok->astOperand2();
if (tok->astOperand1()->isNumber()) {
numtok = tok->astOperand1();
vartok = tok->astOperand2();
} else {
numtok = tok->astOperand2();
vartok = tok->astOperand1();
}
if (vartok->str() == "=" && vartok->astOperand1() && vartok->astOperand2())
vartok = vartok->astOperand1();
if (!vartok->isName() || !numtok->isNumber() || !MathLib::isInt(numtok->str()))
continue;
} else if (tok->str() == "!") {
@ -913,7 +926,7 @@ static void valueFlowAfterCondition(TokenList *tokenlist, ErrorLogger *errorLogg
} else if (tok->isName() &&
(Token::Match(tok->astParent(), "%oror%|&&") ||
Token::Match(tok->tokAt(-2), "if|while ( %var% )"))) {
Token::Match(tok->tokAt(-2), "if|while ( %var% [)=]"))) {
vartok = tok;
numtok = nullptr;
@ -964,7 +977,9 @@ static void valueFlowAfterCondition(TokenList *tokenlist, ErrorLogger *errorLogg
const Token *top = tok->astTop();
if (top && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) {
// does condition reassign variable?
if (isVariableChanged(top,top->link(),varid)) {
if (tok != top->astOperand2() &&
Token::Match(top->astOperand2(), "%oror%|&&") &&
isVariableChanged(top,top->link(),varid)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok, "assignment in condition");
continue;

39
test/testvalueflow.cpp
View File

@ -907,6 +907,45 @@ private:
"}";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 3));
code = "void f(int x) {\n"
" while (11 != (x = dostuff())) {}\n"
" a = x;\n"
"}";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 11));
code = "void f(int x) {\n"
" while (11 != (x = dostuff()) && y) {}\n"
" a = x;\n"
"}";
TODO_ASSERT_EQUALS(true, false, testValueOfX(code, 3U, 11));
code = "void f(int x) {\n"
" while (x = dostuff()) {}\n"
" a = x;\n"
"}";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 0));
code = "void f(const Token *x) {\n" // #5866
" x = x->next();\n"
" while (x) { x = x->next(); }\n"
" if (x->str()) {}\n"
"}";
ASSERT_EQUALS(true, testValueOfX(code, 4U, 0));
code = "void f(const Token *x) {\n"
" while (0 != (x = x->next)) {}\n"
" x->ab = 0;\n"
"}\n";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 0));
code = "void f(const Token* x) {\n"
" while (0 != (x = x->next)) {}\n"
" if (x->str) {\n" // <- possible value 0
" x = y;\n" // <- this caused some problem
" }\n"
"}\n";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 0));
// conditional code after if/else/while
code = "void f(int x) {\n"
" if (x == 2) {}\n"