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Fix 10647: FN knownConditionTrueFalse for impossible Boolean value (#3968) 

* Add impossible values for bool

* Fix valueflow tests

* Fix assertion failure

* Add test

* Format
This commit is contained in:
Paul Fultz II 2022-04-03 13:04:05 -05:00 committed by GitHub
parent 7a7b3e40eb
commit 0547cbcd26
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 38 additions and 18 deletions
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16
lib/valueflow.cpp
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@ -374,7 +374,7 @@ static const Token *getCastTypeStartToken(const Token *parent)
// does the operation cause a loss of information?
static bool isNonInvertibleOperation(const Token* tok)
{
return tok->isComparisonOp() || Token::Match(tok, "%|/|&|%or%|<<|>>");
return tok->isComparisonOp() || Token::Match(tok, "%|/|&|%or%|<<|>>|%oror%|&&");
}
static bool isComputableValue(const Token* parent, const ValueFlow::Value& value)
@ -1549,7 +1549,19 @@ static void valueFlowImpossibleValues(TokenList* tokenList, const Settings* sett
for (Token* tok = tokenList->front(); tok; tok = tok->next()) {
if (tok->hasKnownIntValue())
continue;
if (astIsUnsigned(tok) && !astIsPointer(tok)) {
if (Token::Match(tok, "true|false"))
continue;
if (astIsBool(tok) || Token::Match(tok, "%comp%")) {
ValueFlow::Value lower{-1};
lower.bound = ValueFlow::Value::Bound::Upper;
lower.setImpossible();
setTokenValue(tok, lower, settings);
ValueFlow::Value upper{2};
upper.bound = ValueFlow::Value::Bound::Lower;
upper.setImpossible();
setTokenValue(tok, upper, settings);
} else if (astIsUnsigned(tok) && !astIsPointer(tok)) {
std::vector<MathLib::bigint> minvalue = minUnsignedValue(tok);
if (minvalue.empty())
continue;

9
test/testcondition.cpp
View File

@ -4008,6 +4008,15 @@ private:
" }\n"
"};\n");
ASSERT_EQUALS("", errout.str());
check("void f(const uint32_t u) {\n"
" const uint32_t v = u < 4;\n"
" if (v) {\n"
" const uint32_t w = v < 2;\n"
" if (w) {}\n"
" }\n"
"}\n");
ASSERT_EQUALS("[test.cpp:5]: (style) Condition 'w' is always true\n", errout.str());
}
void alwaysTrueSymbolic()

31
test/testvalueflow.cpp
View File

@ -526,7 +526,7 @@ private:
#define valueOfTok(code, tokstr) valueOfTok_(code, tokstr, __FILE__, __LINE__)
ValueFlow::Value valueOfTok_(const char code[], const char tokstr[], const char* file, int line) {
std::list<ValueFlow::Value> values = tokenValues_(file, line, code, tokstr);
std::list<ValueFlow::Value> values = removeImpossible(tokenValues_(file, line, code, tokstr));
return values.size() == 1U && !values.front().isTokValue() ? values.front() : ValueFlow::Value();
}
@ -552,8 +552,7 @@ private:
ASSERT_EQUALS(0, valueOfTok("x(NULL);", "NULL").intvalue);
ASSERT_EQUALS((int)('a'), valueOfTok("x='a';", "'a'").intvalue);
ASSERT_EQUALS((int)('\n'), valueOfTok("x='\\n';", "'\\n'").intvalue);
TODO_ASSERT_EQUALS(
0xFFFFFFFF00000000, -1, valueOfTok("x=0xFFFFFFFF00000000;", "0xFFFFFFFF00000000").intvalue); // #7701
TODO_ASSERT_EQUALS(0xFFFFFFFF00000000, 0, valueOfTok("x=0xFFFFFFFF00000000;", "0xFFFFFFFF00000000").intvalue); // #7701
ASSERT_EQUALS_DOUBLE(16, valueOfTok("x=(double)16;", "(").floatValue, 1e-5);
ASSERT_EQUALS_DOUBLE(0.0625, valueOfTok("x=1/(double)16;", "/").floatValue, 1e-5);
@ -977,7 +976,7 @@ private:
" a = !x;\n"
" if (x==0) {}\n"
"}";
values = tokenValues(code,"!");
values = removeImpossible(tokenValues(code, "!"));
ASSERT_EQUALS(1U, values.size());
ASSERT_EQUALS(1, values.back().intvalue);
@ -1077,22 +1076,22 @@ private:
}
// Comparison of string
values = tokenValues("f(\"xyz\" == \"xyz\");", "=="); // implementation defined
values = removeImpossible(tokenValues("f(\"xyz\" == \"xyz\");", "==")); // implementation defined
ASSERT_EQUALS(0U, values.size()); // <- no value
values = tokenValues("f(\"xyz\" == 0);", "==");
values = removeImpossible(tokenValues("f(\"xyz\" == 0);", "=="));
ASSERT_EQUALS(1U, values.size());
ASSERT_EQUALS(0, values.front().intvalue);
values = tokenValues("f(0 == \"xyz\");", "==");
values = removeImpossible(tokenValues("f(0 == \"xyz\");", "=="));
ASSERT_EQUALS(1U, values.size());
ASSERT_EQUALS(0, values.front().intvalue);
values = tokenValues("f(\"xyz\" != 0);", "!=");
values = removeImpossible(tokenValues("f(\"xyz\" != 0);", "!="));
ASSERT_EQUALS(1U, values.size());
ASSERT_EQUALS(1, values.front().intvalue);
values = tokenValues("f(0 != \"xyz\");", "!=");
values = removeImpossible(tokenValues("f(0 != \"xyz\");", "!="));
ASSERT_EQUALS(1U, values.size());
ASSERT_EQUALS(1, values.front().intvalue);
}
@ -3771,7 +3770,7 @@ private:
" while (s.x < y)\n" // s.x does not have known value
" s.x++;\n"
"}";
values = tokenValues(code, "<");
values = removeImpossible(tokenValues(code, "<"));
ASSERT_EQUALS(1, values.size());
ASSERT(values.front().isPossible());
ASSERT_EQUALS(1, values.front().intvalue);
@ -3811,7 +3810,7 @@ private:
" if (*b > 0) {\n" // *b does not have known value
" }\n"
"}";
values = tokenValues(code, ">");
values = removeImpossible(tokenValues(code, ">"));
ASSERT_EQUALS(1, values.size());
ASSERT(values.front().isPossible());
ASSERT_EQUALS(1, values.front().intvalue);
@ -3824,7 +3823,7 @@ private:
" dostuff(&pvd);\n"
" } while (condition)\n"
"}";
values = tokenValues(code, "==");
values = removeImpossible(tokenValues(code, "=="));
ASSERT_EQUALS(1, values.size());
ASSERT(values.front().isPossible());
ASSERT_EQUALS(1, values.front().intvalue);
@ -3834,7 +3833,7 @@ private:
"void foo(struct S s) {\n"
" for (s.x = 0; s.x < 127; s.x++) {}\n"
"}";
values = tokenValues(code, "<"); // TODO: comparison can be true or false
values = removeImpossible(tokenValues(code, "<")); // TODO: comparison can be true or false
ASSERT_EQUALS(true, values.empty());
}
@ -5128,7 +5127,7 @@ private:
" if (b && i == j) return;\n"
" if(i != j) {}\n"
"}\n";
ASSERT_EQUALS(true, tokenValues(code, "!=").empty());
ASSERT_EQUALS(true, removeImpossible(tokenValues(code, "!=")).empty());
code = "void f(int i, int j) {\n"
" if (i == j) {\n"
@ -5156,7 +5155,7 @@ private:
" if (i != j) {}\n"
" }\n"
"}\n";
ASSERT_EQUALS(true, tokenValues(code, "!=").empty());
ASSERT_EQUALS(true, removeImpossible(tokenValues(code, "!=")).empty());
code = "void f(bool b, int i, int j) {\n"
" if (b || i == j) {} else {\n"
@ -5170,7 +5169,7 @@ private:
" if (i != j) {}\n"
" }\n"
"}\n";
ASSERT_EQUALS(true, tokenValues(code, "!=").empty());
ASSERT_EQUALS(true, removeImpossible(tokenValues(code, "!=")).empty());
code = "void foo()\n" // #8924
"{\n"