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Fixed #3228 (false positive: possible null pointer dereference)

This commit is contained in:
Daniel Marjamäki 2011-10-30 17:59:38 +01:00
parent 7035d4cdd2
commit 63937f592e
2 changed files with 20 additions and 8 deletions
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9
lib/checknullpointer.cpp
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@ -436,6 +436,8 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
continue; continue;
} }
bool inconclusive = false;
/** /**
* @todo There are lots of false negatives here. A dereference * @todo There are lots of false negatives here. A dereference
* is only investigated if a few specific conditions are met. * is only investigated if a few specific conditions are met.
@ -444,6 +446,11 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
// dereference in assignment // dereference in assignment
if (Token::Match(tok1, "[;{}] %var% . %var%")) { if (Token::Match(tok1, "[;{}] %var% . %var%")) {
tok1 = tok1->next(); tok1 = tok1->next();
if (tok1->strAt(3) == "(") {
if (!_settings->inconclusive)
continue;
inconclusive = true;
}
} }
// dereference in assignment // dereference in assignment
@ -559,7 +566,7 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
else if (Token::Match(tok2, "if ( !| %varid% )|&&", varid1)) { else if (Token::Match(tok2, "if ( !| %varid% )|&&", varid1)) {
// Is this variable a pointer? // Is this variable a pointer?
if (isPointer(varid1)) if (isPointer(varid1))
nullPointerError(tok1, varname, tok2->linenr()); nullPointerError(tok1, varname, tok2->linenr(), inconclusive);
break; break;
} }
} }

19
test/testnullpointer.cpp
View File

@ -256,13 +256,6 @@ private:
"}\n"); "}\n");
ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 3\n", errout.str()); ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 3\n", errout.str());
check("void foo(ABC *abc) {\n"
" abc->do_something();\n"
" if (abc)\n"
" ;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 3\n", errout.str());
check("void foo(ABC *abc) {\n" check("void foo(ABC *abc) {\n"
" if (abc->a == 3) {\n" " if (abc->a == 3) {\n"
" return;\n" " return;\n"
@ -432,6 +425,18 @@ private:
" if (abc) {}\n" " if (abc) {}\n"
"}"); "}");
ASSERT_EQUALS("", errout.str()); ASSERT_EQUALS("", errout.str());
// #3228 - calling function with null object
{
const char code[] = "void f(Fred *fred) {\n"
" fred->x();\n"
" if (fred) { }\n"
"}";
check(code);
ASSERT_EQUALS("", errout.str());
check(code, true);
ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: fred - otherwise it is redundant to check if fred is null at line 3\n", errout.str());
}
} }
// Dereferencing a pointer and then checking if it is null // Dereferencing a pointer and then checking if it is null