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Fixed false positive #6663: Better support for loops in CheckStl::readingEmptyStlContainer()

This commit is contained in:
PKEuS 2015-05-02 13:54:13 +02:00
parent dc54676289
commit 4cbbd44d49
3 changed files with 62 additions and 37 deletions
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89
lib/checkstl.cpp
View File

@ -1514,6 +1514,36 @@ void CheckStl::dereferenceInvalidIteratorError(const Token* deref, const std::st
void CheckStl::readingEmptyStlContainer_parseUsage(const Token* tok, bool map, std::set<unsigned int>& empty, bool noerror)
{
// Check for various conditions for the way stl containers and variables can be used
if (tok->strAt(1) == "=" || (tok->strAt(1) == "[" && Token::simpleMatch(tok->linkAt(1), "] ="))) {
// Assignment (LHS)
empty.erase(tok->varId());
} else if (Token::Match(tok, "%name% [")) {
// Access through operator[]
if (map) { // operator[] inserts an element, if used on a std::map
if (!noerror && tok->strAt(-1) == "=")
readingEmptyStlContainerError(tok);
empty.erase(tok->varId());
} else if (!noerror)
readingEmptyStlContainerError(tok);
} else if (Token::Match(tok, "%name% . %type% (")) {
// Member function call
if (Token::Match(tok->tokAt(2), "find|at|data|c_str|back|front|empty|top|size|count")) { // These functions read from the container
if (!noerror)
readingEmptyStlContainerError(tok);
} else
empty.erase(tok->varId());
} else if (tok->strAt(-1) == "=") {
// Assignment (RHS)
if (!noerror)
readingEmptyStlContainerError(tok);
} else {
// Unknown usage. Assume it is initialized.
empty.erase(tok->varId());
}
}
void CheckStl::readingEmptyStlContainer()
{
@ -1535,14 +1565,28 @@ void CheckStl::readingEmptyStlContainer()
if (i->type != Scope::eFunction)
continue;
const Token* restartTok = nullptr;
for (const Token *tok = i->classStart->next(); tok != i->classEnd; tok = tok->next()) {
if (Token::Match(tok, "for|while")) { // Loops and end of scope clear the sets.
restartTok = tok->linkAt(1); // Check condition to catch looping over empty containers
} else if (tok == restartTok || Token::Match(tok, "do|}")) {
const Token* tok2 = tok->linkAt(1);
if (!tok2)
continue;
tok2 = tok2->next();
for (const Token* end2 = tok2->link(); tok2 && tok2 != end2; tok2 = tok2->next()) {
if (!tok2->varId())
continue;
const bool map = empty_map.find(tok2->varId()) != empty_map.end();
if (!map && empty_nonmap.find(tok2->varId()) == empty_nonmap.end())
continue;
if (map)
readingEmptyStlContainer_parseUsage(tok2, true, empty_map, true);
else
readingEmptyStlContainer_parseUsage(tok2, false, empty_nonmap, true);
}
} else if (Token::Match(tok, "do|}")) {
empty_map.clear();
empty_nonmap.clear();
restartTok = nullptr;
}
if (!tok->varId())
@ -1571,39 +1615,10 @@ void CheckStl::readingEmptyStlContainer()
if (!map && empty_nonmap.find(tok->varId()) == empty_nonmap.end())
continue;
// Check for various conditions for the way stl containers and variables can be used
if (tok->strAt(1) == "=" || (tok->strAt(1) == "[" && Token::simpleMatch(tok->linkAt(1), "] ="))) {
// Assignment (LHS)
if (map)
empty_map.erase(tok->varId());
else
empty_nonmap.erase(tok->varId());
} else if (Token::Match(tok, "%name% [")) {
// Access through operator[]
if (map) { // operator[] inserts an element, if used on a std::map
if (tok->strAt(-1) == "=")
readingEmptyStlContainerError(tok);
empty_map.erase(tok->varId());
} else
readingEmptyStlContainerError(tok);
} else if (Token::Match(tok, "%name% . %type% (")) {
// Member function call
if (Token::Match(tok->tokAt(2), "find|at|data|c_str|back|front|empty|top|size|count")) // These functions read from the container
readingEmptyStlContainerError(tok);
else if (map)
empty_map.erase(tok->varId());
else
empty_nonmap.erase(tok->varId());
} else if (tok->strAt(-1) == "=") {
// Assignment (RHS)
readingEmptyStlContainerError(tok);
} else {
// Unknown usage. Assume it is initialized.
if (map)
empty_map.erase(tok->varId());
else
empty_nonmap.erase(tok->varId());
}
if (map)
readingEmptyStlContainer_parseUsage(tok, true, empty_map, false);
else
readingEmptyStlContainer_parseUsage(tok, false, empty_nonmap, false);
}
empty_map.clear();
empty_nonmap.clear();

2
lib/checkstl.h
View File

@ -158,6 +158,8 @@ private:
*/
void eraseCheckLoop(const Token *it);
void readingEmptyStlContainer_parseUsage(const Token* tok, bool map, std::set<unsigned int>& empty, bool noerror);
void missingComparisonError(const Token *incrementToken1, const Token *incrementToken2);
void string_c_strThrowError(const Token *tok);
void string_c_strError(const Token *tok);

8
test/teststl.cpp
View File

@ -2671,6 +2671,14 @@ private:
" for(int i = 0; i < v.size(); i++) { cout << v[i]; }\n"
"}", true);
ASSERT_EQUALS("[test.cpp:3]: (style, inconclusive) Reading from empty STL container\n", errout.str());
// #6663
check("void foo() {\n"
" std::set<int> container;\n"
" while (container.size() < 5)\n"
" container.insert(22);\n"
"}");
ASSERT_EQUALS("", errout.str());
}
};