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AssignIf: Detect mistake in such code: 'int x=y&4; if ((x==3)||..'

This commit is contained in:
Daniel Marjamäki 2012-09-26 20:15:46 +02:00
parent 9e297c95f2
commit 9f7a0146d0
3 changed files with 19 additions and 9 deletions
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18
lib/checkassignif.cpp
View File

@ -54,13 +54,17 @@ void CheckAssignIf::assignIf()
for (const Token *tok2 = tok->tokAt(4); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(" || tok2->str() == "}" || tok2->str() == "=")
break;
if (Token::Match(tok2,"if ( %varid% %any% %num% &&|%oror%|)", varid)) {
const std::string& op(tok2->strAt(3));
const MathLib::bigint num2 = MathLib::toLongNumber(tok2->strAt(4));
if (Token::Match(tok2,"if ( (| %varid% %any% %num% &&|%oror%|)", varid)) {
const Token *vartok = tok2->tokAt(tok2->strAt(2)=="(" ? 3 : 2);
const std::string& op(vartok->strAt(1));
const MathLib::bigint num2 = MathLib::toLongNumber(vartok->strAt(2));
std::string condition;
if (Token::simpleMatch(tok2, "if ( ("))
condition = "'" + vartok->str() + op + vartok->strAt(2) + "'";
if (op == "==" && (num & num2) != ((bitop=='&') ? num2 : num))
assignIfError(tok2, false);
assignIfError(tok2, condition, false);
else if (op == "!=" && (num & num2) != ((bitop=='&') ? num2 : num))
assignIfError(tok2, true);
assignIfError(tok2, condition, true);
break;
}
}
@ -68,11 +72,11 @@ void CheckAssignIf::assignIf()
}
}
void CheckAssignIf::assignIfError(const Token *tok, bool result)
void CheckAssignIf::assignIfError(const Token *tok, const std::string &condition, bool result)
{
reportError(tok, Severity::style,
"assignIfError",
"Mismatching assignment and comparison, comparison is always " + std::string(result ? "true" : "false") + ".");
"Mismatching assignment and comparison, comparison " + condition + (condition.empty()?"":" ") + "is always " + std::string(result ? "true" : "false") + ".");
}

4
lib/checkassignif.h
View File

@ -63,7 +63,7 @@ public:
private:
void assignIfError(const Token *tok, bool result);
void assignIfError(const Token *tok, const std::string &condition, bool result);
void comparisonError(const Token *tok,
const std::string &bitop,
@ -76,7 +76,7 @@ private:
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
CheckAssignIf c(0, settings, errorLogger);
c.assignIfError(0, false);
c.assignIfError(0, "", false);
c.comparisonError(0, "&", 6, "==", 1, false);
c.multiConditionError(0,1);
}

6
test/testassignif.cpp
View File

@ -74,6 +74,12 @@ private:
"}\n");
ASSERT_EQUALS("[test.cpp:4]: (style) Mismatching assignment and comparison, comparison is always true.\n", errout.str());
check("void foo(int x) {\n"
" int y = x & 4;\n"
" if ((y == 3) && (z == 1));\n"
"}\n");
ASSERT_EQUALS("[test.cpp:3]: (style) Mismatching assignment and comparison, comparison 'y==3' is always false.\n", errout.str());
// |
check("void foo(int x) {\n"
" int y = x | 0x14;\n"