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Improve check: check for known empty containers passed to algorithms (#2768)

This commit is contained in:
Paul Fultz II 2020-09-02 00:11:23 -05:00 committed by GitHub
parent 8e79b0c8bc
commit dea5a23c34
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 92 additions and 60 deletions
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65
lib/checkstl.cpp
View File

@ -2501,24 +2501,50 @@ void CheckStl::useStlAlgorithm()
}
}
void CheckStl::knownEmptyContainerLoopError(const Token *tok)
void CheckStl::knownEmptyContainerError(const Token *tok, const std::string& algo)
{
const std::string cont = tok ? tok->expressionString() : std::string("var");
const std::string var = tok ? tok->expressionString() : std::string("var");
reportError(tok, Severity::style,
"knownEmptyContainerLoop",
"Iterating over container '" + cont + "' that is always empty.", CWE398, false);
std::string msg;
if (astIsIterator(tok)) {
msg = "Using " + algo + " with iterator '" + var + "' that is always empty.";
} else {
msg = "Iterating over container '" + var + "' that is always empty.";
}
void CheckStl::knownEmptyContainerLoop()
reportError(tok, Severity::style,
"knownEmptyContainer",
msg, CWE398, false);
}
static bool isKnownEmptyContainer(const Token* tok)
{
if (!tok)
return false;
for (const ValueFlow::Value& v:tok->values()) {
if (!v.isKnown())
continue;
if (!v.isContainerSizeValue())
continue;
if (v.intvalue != 0)
continue;
return true;
}
return false;
}
void CheckStl::knownEmptyContainer()
{
if (!mSettings->isEnabled(Settings::STYLE))
return;
for (const Scope *function : mTokenizer->getSymbolDatabase()->functionScopes) {
for (const Token *tok = function->bodyStart; tok != function->bodyEnd; tok = tok->next()) {
// Parse range-based for loop
if (!Token::simpleMatch(tok, "for ("))
if (!Token::Match(tok, "%name% ( !!)"))
continue;
// Parse range-based for loop
if (tok->str() == "for") {
if (!Token::simpleMatch(tok->next()->link(), ") {"))
continue;
const Token *bodyTok = tok->next()->link()->next();
@ -2526,19 +2552,26 @@ void CheckStl::knownEmptyContainerLoop()
if (!Token::simpleMatch(splitTok, ":"))
continue;
const Token* contTok = splitTok->astOperand2();
if (!contTok)
if (!isKnownEmptyContainer(contTok))
continue;
for (const ValueFlow::Value& v:contTok->values()) {
if (!v.isKnown())
knownEmptyContainerError(contTok, "");
} else {
const std::vector<const Token *> args = getArguments(tok);
if (args.empty())
continue;
if (!v.isContainerSizeValue())
for (int argnr = 1; argnr <= args.size(); ++argnr) {
const Library::ArgumentChecks::IteratorInfo *i = mSettings->library.getArgIteratorInfo(tok, argnr);
if (!i)
continue;
if (v.intvalue != 0)
const Token * const argTok = args[argnr - 1];
if (!isKnownEmptyContainer(argTok))
continue;
knownEmptyContainerLoopError(contTok);
knownEmptyContainerError(argTok, tok->str());
break;
}
}
}
}
}

8
lib/checkstl.h
View File

@ -81,7 +81,7 @@ public:
checkStl.invalidContainerLoop();
checkStl.mismatchingContainers();
checkStl.mismatchingContainerIterator();
checkStl.knownEmptyContainerLoop();
checkStl.knownEmptyContainer();
checkStl.stlBoundaries();
checkStl.checkDereferenceInvalidIterator();
@ -190,7 +190,7 @@ public:
/** @brief Look for loops that can replaced with std algorithms */
void useStlAlgorithm();
void knownEmptyContainerLoop();
void knownEmptyContainer();
void checkMutexes();
@ -238,7 +238,7 @@ private:
void useStlAlgorithmError(const Token *tok, const std::string &algoName);
void knownEmptyContainerLoopError(const Token *tok);
void knownEmptyContainerError(const Token *tok, const std::string& algo);
void globalLockGuardError(const Token *tok);
void localMutexError(const Token *tok);
@ -279,7 +279,7 @@ private:
c.dereferenceInvalidIteratorError(nullptr, "i");
c.readingEmptyStlContainerError(nullptr);
c.useStlAlgorithmError(nullptr, "");
c.knownEmptyContainerLoopError(nullptr);
c.knownEmptyContainerError(nullptr, "");
c.globalLockGuardError(nullptr);
c.localMutexError(nullptr);
}

65
test/teststl.cpp
View File

@ -167,7 +167,7 @@ private:
TEST_CASE(invalidContainerLoop);
TEST_CASE(findInsert);
TEST_CASE(checkKnownEmptyContainerLoop);
TEST_CASE(checkKnownEmptyContainer);
TEST_CASE(checkMutexes);
}
@ -547,13 +547,11 @@ private:
}
void iterator5() {
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::find(ints1.begin(), ints2.end(), 22);\n"
"}");
ASSERT_EQUALS("[test.cpp:5]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
ASSERT_EQUALS("[test.cpp:3]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
errout.str());
}
@ -579,56 +577,44 @@ private:
}
void iterator7() {
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::inplace_merge(ints1.begin(), std::advance(ints1.rbegin(), 5), ints2.end());\n"
"}");
ASSERT_EQUALS("[test.cpp:5]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
ASSERT_EQUALS("[test.cpp:3]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
errout.str());
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::inplace_merge(ints1.begin(), std::advance(ints2.rbegin(), 5), ints1.end());\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void iterator8() {
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::find_first_of(ints1.begin(), ints2.end(), ints1.begin(), ints1.end());\n"
"}");
ASSERT_EQUALS("[test.cpp:5]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
ASSERT_EQUALS("[test.cpp:3]: (error) Iterators of different containers 'ints1' and 'ints2' are used together.\n",
errout.str());
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::find_first_of(ints1.begin(), ints1.end(), ints2.begin(), ints1.end());\n"
"}");
ASSERT_EQUALS("[test.cpp:5]: (error) Iterators of different containers 'ints2' and 'ints1' are used together.\n",
ASSERT_EQUALS("[test.cpp:3]: (error) Iterators of different containers 'ints2' and 'ints1' are used together.\n",
errout.str());
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::find_first_of(foo.bar.begin(), foo.bar.end()-6, ints2.begin(), ints1.end());\n"
"}");
ASSERT_EQUALS("[test.cpp:5]: (error) Iterators of different containers 'ints2' and 'ints1' are used together.\n",
ASSERT_EQUALS("[test.cpp:3]: (error) Iterators of different containers 'ints2' and 'ints1' are used together.\n",
errout.str());
check("void foo()\n"
check("void foo(std::vector<int> ints1, std::vector<int> ints2)\n"
"{\n"
" std::vector<int> ints1;\n"
" std::vector<int> ints2;\n"
" std::vector<int>::iterator it = std::find_first_of(ints1.begin(), ints1.end(), ints2.begin(), ints2.end());\n"
"}");
ASSERT_EQUALS("", errout.str());
@ -3397,8 +3383,7 @@ private:
"}");
ASSERT_EQUALS("", errout.str());
check("void f() {\n"
" std::vector<int> a;\n"
check("void f(std::vector<int> a) {\n"
" std::remove(a.begin(), a.end(), val);\n"
" std::remove_if(a.begin(), a.end(), val);\n"
" std::unique(a.begin(), a.end(), val);\n"
@ -3406,9 +3391,9 @@ private:
" a.erase(std::remove(a.begin(), a.end(), val));\n"
" std::remove(\"foo.txt\");\n"
"}");
ASSERT_EQUALS("[test.cpp:3]: (warning) Return value of std::remove() ignored. Elements remain in container.\n"
"[test.cpp:4]: (warning) Return value of std::remove_if() ignored. Elements remain in container.\n"
"[test.cpp:5]: (warning) Return value of std::unique() ignored. Elements remain in container.\n", errout.str());
ASSERT_EQUALS("[test.cpp:2]: (warning) Return value of std::remove() ignored. Elements remain in container.\n"
"[test.cpp:3]: (warning) Return value of std::remove_if() ignored. Elements remain in container.\n"
"[test.cpp:4]: (warning) Return value of std::unique() ignored. Elements remain in container.\n", errout.str());
// #4431 - fp
check("bool f() {\n"
@ -4648,7 +4633,7 @@ private:
ASSERT_EQUALS("", errout.str());
}
void checkKnownEmptyContainerLoop() {
void checkKnownEmptyContainer() {
check("void f() {\n"
" std::vector<int> v;\n"
" for(auto x:v) {}\n"
@ -4676,6 +4661,20 @@ private:
"}\n",
true);
ASSERT_EQUALS("", errout.str());
check("void f() {\n"
" std::vector<int> v;\n"
" std::sort(v.begin(), v.end());\n"
"}\n",
true);
ASSERT_EQUALS("[test.cpp:3]: (style) Using sort with iterator 'v.begin()' that is always empty.\n", errout.str());
check("void f() {\n"
" std::vector<int> v;\n"
" v.insert(v.end(), 1);\n"
"}\n",
true);
ASSERT_EQUALS("", errout.str());
}
void checkMutexes() {