[cfe-dev] [clang-tidy] clang-analyzer-core.CallAndMessage and clang-analyzer-alpha.deadcode.UnreachableCode

[Piotr Padlewski via cfe-dev]

Hi guys,
So I was running clang-tidy on some larger code base recently, and I got
warning like this:



warning: optimization flag '-fno-inline-functions-called-once' is not
supported [clang-diagnostic-ignored-optimization-argument]
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:18:26: warning:
Called C++ object pointer is uninitialized
[clang-analyzer-core.CallAndMessage]
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))
                         ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:13:8: note:
Assuming 'pos' is not equal to 'npos'
    if(pos == std::string::npos)
       ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:13:5: note:
Taking false branch
    if(pos == std::string::npos)
    ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:18:28: note:
'__range' initialized to a garbage value
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))
                           ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:18:26: note:
Called C++ object pointer is uninitialized
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))
                         ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:18:26: warning:
This statement is never executed
[clang-analyzer-alpha.deadcode.UnreachableCode]
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))
                         ^
/home/ppadlewski/fast-clang/Components/Stats/Aggregate.cc:18:26: note: This
statement is never executed
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))



Code looks like this:
void parseAggregate(std::string& key, std::vector<std::string>& values,
const std::string& aggregate)
{
    std::string::size_type pos = aggregate.find('=');
    if(pos == std::string::npos)
        throw FastException("Expected \"key=value,value...\" format.");
    key = aggregate.substr(0, pos);
    values.clear();
    typedef boost::tokenizer<boost::char_separator<char>> tokenizer;
    for(const auto& token: tokenizer(aggregate.begin()+pos+1,
aggregate.end(), boost::char_separator<char>(",")))
        values.push_back(token);
}

Is it bug in the analyzer, or boost::tokenizer is broken? (1.55)

Best
Piotr Padlewski
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