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ValueFlow: Set values in else branch even when the first branch modifies the value (#1309) 

* Set values in else branch even when the first branch modifies the value

* Move tests

* Add check for goto

* Remvoe todo

* Also check scope is noreturn

* Use isEscapeScope when variables are changed
This commit is contained in:
Paul Fultz II 2018-07-25 15:59:54 -05:00 committed by Daniel Marjamäki
parent 01ceb9bae7
commit f093692551
2 changed files with 75 additions and 4 deletions
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15
lib/valueflow.cpp
View File

@ -1543,6 +1543,14 @@ static bool evalAssignment(ValueFlow::Value &lhsValue, const std::string &assign
return true;
}
static bool isEscapeScope(const Token* tok, TokenList * tokenlist)
{
if(!Token::simpleMatch(tok, "{"))
return false;
return Token::findmatch(tok, "return|continue|break|throw|goto", tok->link()) ||
(tokenlist && tokenlist->getSettings()->library.isScopeNoReturn(tok->link(), nullptr));
}
static bool valueFlowForward(Token * const startToken,
const Token * const endToken,
const Variable * const var,
@ -1848,8 +1856,8 @@ static bool valueFlowForward(Token * const startToken,
// noreturn scopes..
if ((number_of_if > 0 || Token::findmatch(tok2, "%varid%", start, varid)) &&
(Token::findmatch(start, "return|continue|break|throw", end) ||
(Token::simpleMatch(end,"} else {") && Token::findmatch(end, "return|continue|break|throw", end->linkAt(2))))) {
(isEscapeScope(start, tokenlist) ||
(Token::simpleMatch(end,"} else {") && isEscapeScope(end->tokAt(2), tokenlist)))) {
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + ". noreturn conditional scope.");
return false;
@ -1859,8 +1867,7 @@ static bool valueFlowForward(Token * const startToken,
if ((!read || number_of_if == 0) &&
Token::simpleMatch(tok2, "if (") &&
!(Token::simpleMatch(end, "} else {") &&
(Token::findmatch(end, "%varid%", end->linkAt(2), varid) ||
Token::findmatch(end, "return|continue|break|throw", end->linkAt(2))))) {
isEscapeScope(end->tokAt(2), tokenlist))) {
++number_of_if;
tok2 = end;
} else {

64
test/testvalueflow.cpp
View File

@ -1583,6 +1583,23 @@ private:
"}";
ASSERT_EQUALS(false, testValueOfX(code, 9U, 0));
code = "void f(int i) {\n"
" bool x = false;\n"
" if (i == 0) { x = true; }\n"
" else if (x && i == 1) {}\n"
"}\n";
ASSERT_EQUALS(true, testValueOfX(code, 4U, 0));
code = "void f(int i) {\n"
" bool x = false;\n"
" while(i > 0) {\n"
" i++;\n"
" if (i == 0) { x = true; }\n"
" else if (x && i == 1) {}\n"
" }\n"
"}\n";
ASSERT_EQUALS(false, testValueOfX(code, 6U, 0));
// multivariables
code = "void f(int a) {\n"
" int x = a;\n"
@ -3137,6 +3154,53 @@ private:
"}";
values = tokenValues(code, "x ; }");
ASSERT_EQUALS(true, values.empty());
code = "void b(bool d, bool e) {\n"
" int c;\n"
" if (d)\n"
" c = 0;\n"
" if (e)\n"
" goto;\n"
" c++;\n"
"}\n";
values = tokenValues(code, "c ++ ; }");
ASSERT_EQUALS(true, values.empty());
code = "void b(bool d, bool e) {\n"
" int c;\n"
" if (d)\n"
" c = 0;\n"
" if (e)\n"
" return;\n"
" c++;\n"
"}\n";
values = tokenValues(code, "c ++ ; }");
ASSERT_EQUALS(true, values.empty());
code = "void b(bool d, bool e) {\n"
" int c;\n"
" if (d)\n"
" c = 0;\n"
" if (e)\n"
" exit();\n"
" c++;\n"
"}\n";
values = tokenValues(code, "c ++ ; }");
ASSERT_EQUALS(true, values.empty());
code = "void b(bool d, bool e) {\n"
" int c;\n"
" if (d)\n"
" c = 0;\n"
" else if (!d)\n"
" c = 0;\n"
" c++;\n"
"}\n";
values = tokenValues(code, "c ++ ; }");
ASSERT_EQUALS(true, values.size() == 2);
ASSERT_EQUALS(true, values.front().isUninitValue() || values.back().isUninitValue());
ASSERT_EQUALS(true, values.front().isPossible() || values.back().isPossible());
ASSERT_EQUALS(true, values.front().intvalue == 0 || values.back().intvalue == 0);
}
};