[cfe-dev] Sudden warnings

[Csaba Raduly]

Hi all,

Compiling the following snippet:

typedef unsigned long size_t; // line 1

template<class K, class T>
class map {
private:

  size_t num_m;
  size_t max_m;

  static const size_t start_size = 1, factor = 2; // 10

  map(const map&);
  map& operator=(const map&);
public:
  static const size_t max_length = -1; // 15

  map() : num_m(0), max_m(0) { }

  ~map() {
  }

  void add(const K& , T ) {
    if (num_m > 0) {
      if (num_m >= max_m) {
        if (max_m <= max_length / factor) // 25
          max_m *= factor;
        else if (max_m < max_length)
          max_m = max_length;
      }
    } else {
      max_m = start_size; // 31
    }
    num_m++;
  }
};

class Type;

namespace { // no warnings without it

  enum state { PROCESSING = -1, ANSWER_NO, ANSWER_YES };

  struct memoizer : private map<Type*, state> {
    memoizer() : map<Type*, state>() {}

    void remember (Type *t, state s) {
        add(t, s);
    }
  };
}

with

clang version 2.9 (trunk 126116)
Target: x86_64-unknown-linux-gnu
Thread model: posix"

results in the following warnings (errors due to -Werror)

TypeI.cc:15:23: error: variable 'map<Type *,
<anonymous>::state>::max_length' has internal linkage but is not
defined
  static const size_t max_length = -1;
                      ^
TypeI.cc:25:22: note: used here
        if (max_m <= max_length / factor)
                     ^
TypeI.cc:10:39: error: variable 'map<Type *,
<anonymous>::state>::factor' has internal linkage but is not defined
  static const size_t start_size = 1, factor = 2;
                                      ^
TypeI.cc:25:35: note: used here
        if (max_m <= max_length / factor)
                                  ^
TypeI.cc:10:23: error: variable 'map<Type *,
<anonymous>::state>::start_size' has internal linkage but is not
defined
  static const size_t start_size = 1, factor = 2;
                      ^
TypeI.cc:31:15: note: used here
      max_m = start_size;
              ^

These warnings were not emitted from clang version 2.9 (trunk 125566).

I think clang is too trigger-happy here. Neither G++ nor Comeau online
reproduced these warnings (Comeau complained about the sign change in
line 15 and some functions being defined but not used).

Csaba
-- 
GCS a+ e++ d- C++ ULS$ L+$ !E- W++ P+++$ w++$ tv+ b++ DI D++ 5++
Life is complex, with real and imaginary parts.
"Ok, it boots. Which means it must be bug-free and perfect. " -- Linus Torvalds
"People disagree with me. I just ignore them." -- Linus Torvalds