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Fix issue 8737: FP with identical inner condition due to followVar (#1371)

This commit is contained in:
Paul Fultz II 2018-09-07 13:16:38 -05:00 committed by Daniel Marjamäki
parent 7fdd039bee
commit cb03b9883f
2 changed files with 29 additions and 4 deletions
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21
lib/astutils.cpp
View File

@ -147,14 +147,26 @@ static bool isInLoopCondition(const Token * tok)
return Token::Match(tok->astTop()->previous(), "for|while (");
}
/// If tok2 comes after tok1
static bool precedes(const Token * tok1, const Token * tok2)
{
if(!tok1)
return false;
if(!tok2)
return false;
return tok1->progressValue() < tok2->progressValue();
}
/// This takes a token that refers to a variable and it will return the token
/// to the expression that the variable is assigned to. If its not valid to
/// make such substitution then it will return the original token.
static const Token * followVariableExpression(const Token * tok, bool cpp)
static const Token * followVariableExpression(const Token * tok, bool cpp, const Token * end = nullptr)
{
if (!tok)
return tok;
// Skip following variables that is across multiple files
if(end && end->fileIndex() != tok->fileIndex())
return tok;
// Skip array access
if (Token::Match(tok, "%var% ["))
return tok;
@ -182,8 +194,9 @@ static const Token * followVariableExpression(const Token * tok, bool cpp)
return tok;
if (var->isArgument())
return tok;
const Token * lastTok = precedes(tok, end) ? end : tok;
// If this is in a loop then check if variables are modified in the entire scope
const Token * endToken = (isInLoopCondition(tok) || isInLoopCondition(varTok) || var->scope() != tok->scope()) ? var->scope()->bodyEnd : tok;
const Token * endToken = (isInLoopCondition(tok) || isInLoopCondition(varTok) || var->scope() != tok->scope()) ? var->scope()->bodyEnd : lastTok;
if (!var->isConst() && isVariableChanged(varTok, endToken, tok->varId(), false, nullptr, cpp))
return tok;
// Start at beginning of initialization
@ -254,12 +267,12 @@ bool isSameExpression(bool cpp, bool macro, const Token *tok1, const Token *tok2
return isSameExpression(cpp, macro, tok1, tok2->astOperand1()->astOperand1(), library, pure, errors);
}
if (tok1->str() != tok2->str() && (Token::Match(tok1, "%var%") || Token::Match(tok2, "%var%"))) {
const Token * varTok1 = followVariableExpression(tok1, cpp);
const Token * varTok1 = followVariableExpression(tok1, cpp, tok2);
if (varTok1->str() == tok2->str()) {
followVariableExpressionError(tok1, varTok1, errors);
return isSameExpression(cpp, macro, varTok1, tok2, library, pure, errors);
}
const Token * varTok2 = followVariableExpression(tok2, cpp);
const Token * varTok2 = followVariableExpression(tok2, cpp, tok1);
if (tok1->str() == varTok2->str()) {
followVariableExpressionError(tok2, varTok2, errors);
return isSameExpression(cpp, macro, tok1, varTok2, library, pure, errors);

12
test/testcondition.cpp
View File

@ -2032,6 +2032,18 @@ private:
" }\n"
"}\n");
ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (warning) Identical inner 'if' condition is always true.\n", errout.str());
check("void f() {\n"
" uint32_t value;\n"
" get_value(&value);\n"
" int opt_function_capable = (value >> 28) & 1;\n"
" if (opt_function_capable) {\n"
" value = 0;\n"
" get_value (&value);\n"
" if ((value >> 28) & 1) {}\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void identicalConditionAfterEarlyExit() {