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Forward values after assignment in valueFlowReverse #2226

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Merged
danmar merged 3 commits into from
Oct 3, 2019
Merged

Forward values after assignment in valueFlowReverse #2226

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50ed4db
Forward values after assignment in valueFlowReverse
pfultz2 Sep 29, 2019
d496c4c
Rename variables
pfultz2 Sep 29, 2019
4cf3ae2
Format
pfultz2 Sep 29, 2019
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3 changes: 2 additions & 1 deletion lib/astutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1614,7 +1614,8 @@ static bool isUnchanged(const Token *startToken, const Token *endToken, const st
struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set<int> &exprVarIds, bool local, bool inInnerClass)
{
// Parse the given tokens
for (const Token *tok = startToken; tok != endToken; tok = tok->next()) {

for (const Token* tok = startToken; precedes(tok, endToken); tok = tok->next()) {
if (Token::simpleMatch(tok, "try {")) {
// TODO: handle try
return Result(Result::Type::BAILOUT);
Expand Down
54 changes: 43 additions & 11 deletions lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1841,6 +1841,16 @@ static void valueFlowGlobalStaticVar(TokenList *tokenList, const Settings *setti
}
}

static void valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
const bool constValue,
const bool subFunction,
TokenList* const tokenlist,
ErrorLogger* const errorLogger,
const Settings* settings);

static void valueFlowReverse(TokenList *tokenlist,
Token *tok,
const Token * const varToken,
Expand All @@ -1865,8 +1875,30 @@ static void valueFlowReverse(TokenList *tokenlist,
}

if (tok2->varId() == varid) {
if (tok2->hasKnownValue())
break;
// bailout: assignment
if (Token::Match(tok2->previous(), "!!* %name% =")) {
Token* assignTok = const_cast<Token*>(tok2->next()->astOperand2());
if (!assignTok->hasKnownValue()) {
std::list<ValueFlow::Value> values = {val};
setTokenValue(assignTok, val, settings);
if (val2.condition) {
setTokenValue(assignTok, val2, settings);
values.push_back(val2);
}
const Token* startForwardToken = nextAfterAstRightmostLeaf(tok2->next());
const Token* endForwardToken = tok->scope() ? tok->scope()->bodyEnd : tok;
valueFlowForward(const_cast<Token*>(startForwardToken),
endForwardToken,
assignTok,
values,
false,
false,
tokenlist,
errorLogger,
settings);
}
if (settings->debugwarnings)
bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
break;
Expand Down Expand Up @@ -2062,6 +2094,17 @@ static void valueFlowReverse(TokenList *tokenlist,
}
}

static bool isConditionKnown(const Token* tok, bool then)
{
const char* op = "||";
if (then)
op = "&&";
const Token* parent = tok->astParent();
while (parent && parent->str() == op)
parent = parent->astParent();
return (parent && parent->str() == "(");
}

static void valueFlowBeforeCondition(TokenList *tokenlist, SymbolDatabase *symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
{
for (const Scope * scope : symboldatabase->functionScopes) {
Expand Down Expand Up @@ -4338,17 +4381,6 @@ static void valueFlowAfterAssign(TokenList *tokenlist, SymbolDatabase* symboldat
}
}

static bool isConditionKnown(const Token* tok, bool then)
{
const char * op = "||";
if (then)
op = "&&";
const Token* parent = tok->astParent();
while (parent && parent->str() == op)
parent = parent->astParent();
return (parent && parent->str() == "(");
}

static void valueFlowSetConditionToKnown(const Token* tok, std::list<ValueFlow::Value>& values, bool then)
{
if (values.empty())
Expand Down
20 changes: 20 additions & 0 deletions test/testvalueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,7 @@ class TestValueFlow : public TestFixture {
TEST_CASE(valueFlowBeforeConditionSizeof);
TEST_CASE(valueFlowBeforeConditionSwitch);
TEST_CASE(valueFlowBeforeConditionTernaryOp);
TEST_CASE(valueFlowBeforeConditionForward);

TEST_CASE(valueFlowAfterAssign);
TEST_CASE(valueFlowAfterCondition);
Expand Down Expand Up @@ -1410,6 +1411,25 @@ class TestValueFlow : public TestFixture {
errout.str());
}

void valueFlowBeforeConditionForward()
{
const char* code;

code = "void f(int a) {\n"
" int x = a;\n"
" if (a == 123) {}\n"
" int b = x;\n"
"}";
ASSERT_EQUALS(true, testValueOfX(code, 4U, 123));

code = "void f(int a) {\n"
" int x = a;\n"
" if (a != 123) {}\n"
" int b = x;\n"
"}";
ASSERT_EQUALS(true, testValueOfX(code, 4U, 123));
}

void valueFlowAfterAssign() {
const char *code;

Expand Down