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Improved Check: Warn about number and char literals in boolean expressions (#7750)

This commit is contained in:
Harald Scheidl 2016-10-08 01:57:09 +02:00 committed by PKEuS
parent 0e785e435e
commit 58eb644003
4 changed files with 28 additions and 11 deletions
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9
lib/checkcondition.cpp
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@ -975,7 +975,12 @@ void CheckCondition::alwaysTrueFalse()
for (std::size_t i = 0; i < functions; ++i) {
const Scope * scope = symbolDatabase->functionScopes[i];
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (!Token::Match(tok, "%comp%|!"))
const bool constValCond = Token::Match(tok->tokAt(-2), "if|while ( %num%|%char% )"); // just one number or char inside if|while
const bool constValExpr = Token::Match(tok, "%num%|%char%") && tok->astParent() && Token::Match(tok->astParent(),"&&|%oror%|?"); // just one number or char in boolean expression
const bool compExpr = Token::Match(tok, "%comp%|!"); // a compare expression
if (!(constValCond || constValExpr || compExpr))
continue;
if (tok->link()) // don't write false positives when templates are used
continue;
@ -983,8 +988,6 @@ void CheckCondition::alwaysTrueFalse()
continue;
if (!tok->values.front().isKnown())
continue;
if (!tok->astParent() || !Token::Match(tok->astParent()->previous(), "%name% ("))
continue;
// Don't warn in assertions. Condition is often 'always true' by intention.
// If platform,defines,etc cause 'always false' then that is not dangerous neither.

12
lib/tokenize.cpp
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@ -1859,14 +1859,14 @@ void Tokenizer::combineOperators()
}
}
void Tokenizer::combineStrings()
void Tokenizer::combineStringAndCharLiterals()
{
// Combine wide strings
// Combine wide strings and wide characters
for (Token *tok = list.front();
tok;
tok = tok->next()) {
while (tok->str() == "L" && tok->next() && tok->next()->tokType() == Token::eString) {
// Combine 'L "string"'
if (tok->str() == "L" && tok->next() && (tok->next()->tokType() == Token::eString || tok->next()->tokType() == Token::eChar)) {
// Combine 'L "string"' and 'L 'c''
tok->str(tok->next()->str());
tok->deleteNext();
tok->isLong(true);
@ -3326,8 +3326,8 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
// remove MACRO in variable declaration: MACRO int x;
removeMacroInVarDecl();
// Combine strings
combineStrings();
// Combine strings and character literals, e.g. L"string", L'c', "string1" "string2"
combineStringAndCharLiterals();
// replace inline SQL with "asm()" (Oracle PRO*C). Ticket: #1959
simplifySQL();

2
lib/tokenize.h
View File

@ -466,7 +466,7 @@ public:
void combineOperators();
void combineStrings();
void combineStringAndCharLiterals();
void simplifyNull();

16
test/testcondition.cpp
View File

@ -1552,7 +1552,8 @@ private:
check("void f() {\n"
" if (x & 3 == 2) {}\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (style) Suspicious condition (bitwise operator + comparison); Clarify expression with parentheses.\n", errout.str());
ASSERT_EQUALS("[test.cpp:2]: (style) Suspicious condition (bitwise operator + comparison); Clarify expression with parentheses.\n"
"[test.cpp:2]: (style) Condition '3==2' is always false\n", errout.str());
check("void f() {\n"
" if (a & fred1.x == fred2.y) {}\n"
@ -1726,6 +1727,19 @@ private:
" assert(x == 0);\n"
"}");
ASSERT_EQUALS("", errout.str());
// #7750 warn about number and char literals in boolean expressions
check("void f() {\n"
" if('a'){}\n"
" if(L'b'){}\n"
" if(1 && 'c'){}\n"
" int x = 'd' ? 1 : 2;\n"
"}");
ASSERT_EQUALS("[test.cpp:2]: (style) Condition ''a'' is always true\n"
"[test.cpp:3]: (style) Condition ''b'' is always true\n"
"[test.cpp:4]: (style) Condition '1' is always true\n"
"[test.cpp:4]: (style) Condition ''c'' is always true\n"
"[test.cpp:5]: (style) Condition ''d'' is always true\n", errout.str());
}
void checkInvalidTestForOverflow() {