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

value flow: bailout when variable is used in assignment to itself

This commit is contained in:
Daniel Marjamäki 2014-01-11 15:36:09 +01:00
parent 1fc2c9fe79
commit 75f9111775
2 changed files with 33 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
lib/valueflow.cpp
View File

@ -82,6 +82,24 @@ static const Token * skipValueInConditionalExpression(const Token *tok)
return tok;
}
static bool bailoutSelfAssignment(const Token * const tok)
{
const Token *parent = tok;
while (parent) {
const Token *op = parent;
parent = parent->astParent();
// Assignment where lhs variable exists in rhs => return true
if (parent != NULL &&
parent->astOperand2() == op &&
parent->astOperand1() != NULL &&
parent->str() == "=" &&
parent->astOperand1()->str() == tok->str())
return true;
}
return false;
}
static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
{
for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
@ -152,6 +170,13 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
break;
}
// bailout: variable is used in rhs in assignment to itself
if (bailoutSelfAssignment(tok2)) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + tok2->str() + " is used in rhs in assignment to itself");
break;
}
// assigned by subfunction?
if (bailoutFunctionPar(tok2)) {
if (settings->debugwarnings)

8
test/testvalueflow.cpp
View File

@ -104,6 +104,14 @@ private:
"}";
ASSERT_EQUALS(true, testValueOfX(code, 3U, 123));
// assignment
code = "void f(int x) {\n"
" x = 2 + x;\n"
" if (x == 65);\n"
"}";
ASSERT_EQUALS(false, testValueOfX(code, 2U, 65));
// guarding by &&
code = "void f(int x) {\n"
" if (!x || \n" // <- x can be 0