[Bug c++/52817] g++ do not call a method with same name on some platforms(see small example source attached)

["nospamname at web dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52817

--- Comment #6 from bernd_afa <nospamname at web dot de> 2012-04-01 13:26:40 UTC ---
>Not a bug.  An ellipses conversion sequence is worse than a standard conversion
>sequence, thus readdata(int,void*) is preferred over readdata(int,...) when the
>actual arguments are (int,long*).

The bad cast i only do to avoid extern include files. normaly it use SDL.
The problem happen because the address of the SDL_RWops structure is transfer
wrong. Same in the SDL program, because the 1. method "Wsafile::readdata(int
NumFiles, ...)" is not call on amigaos target. 

Wsafile::Wsafile(SDL_RWops* RWop)
{
    readdata(1,RWop);
}

I attach complete preprocessed file, va-list is used with
__builtin_va_list.currently i have test with 4.5.0 now but other compiler have
same include.

The include for stdarg.h come from the compiler build.

command line was this:
m68k-amigaos-g++ eh-vararg-3.cpp -Wall -Wextra -E > preproc

the result

# 1 "eh-vararg-3.cpp"

# 1 "<built-in>"
# 1 "<command-line>"

# 1 "eh-vararg-3.cpp"

# 1 "/usr/local/amiga/lib/gcc/m68k-amigaos/4.5.0/include/stdarg.h" 1 3 4

# 43 "/usr/local/amiga/lib/gcc/m68k-amigaos/4.5.0/include/stdarg.h" 3 4

typedef __builtin_va_list __gnuc_va_list;

# 105 "/usr/local/amiga/lib/gcc/m68k-amigaos/4.5.0/include/stdarg.h" 3 4

typedef __gnuc_va_list va_list;

# 2 "eh-vararg-3.cpp" 2

...

this is the mail i write to GCC ML. This show more code about the real program
that fail

hello

there is a C++ game called dunelegacy which work on other GCC architecture ok
On G++ 68k it compile ok, but produce wrong code, because there seem something
diffrent in
va_list. The value of
SDL_RWops is transfer wrong.

I do not understand what backend problem is possible to cause this. Please
help.va_list use the
builtin GCC functions

this happen on all 68k compilers i test. (3.x and some 4.x)

See also the source attached of this class

the program flow of the critical part begin here. 

Wsafile::Wsafile(SDL_RWops* RWop)
{
    readdata(1,RWop);
}

......


now there are 2 Methods named readdata, and gcc call the 2. one. This work
wrong. Only when called
the first is ok.

.....

void Wsafile::readdata(int NumFiles, ...) {
    va_list args;
    va_start(args,NumFiles);
    readdata(NumFiles,args);
    va_end(args);
}

/// Helper method for reading and concatinating various WSA-Files.
/**
    This methods reads from the RWops all data and concatinates all the frames
to one animation. The
SDL_RWops
    can be readonly but must support seeking.
    \param  NumFiles    Number of SDL_RWops
    \param  args        SDL_RWops for each wsa-File should be in this va_list.
(can be readonly)
*/
void Wsafile::readdata(int NumFiles, va_list args) {
    unsigned char** Filedata;
    Uint32** Index;
    Uint16* NumberOfFrames;
    bool* extended;

    if((Filedata = (unsigned char**) malloc(sizeof(unsigned char*) * NumFiles))
== NULL) {
        fprintf(stderr, "Wsafile::readdata(): Unable to allocate memory!\n");
        exit(EXIT_FAILURE);
    }


.....................


when i change code to this and rename the first readdata method to
readdata_first then it work

Wsafile::Wsafile(SDL_RWops* RWop)
{
    readdata_first(1,RWop);   <---- I change that line
}

now there is called this method before and all work ok


void Wsafile::readdata_frist(int NumFiles, ...) {   <---- I rename readdata to
readdata_first.
    va_list args;
    va_start(args,NumFiles);
    readdata(NumFiles,args);
    va_end(args);
}

/// Helper method for reading and concatinating various WSA-Files.
/**
    This methods reads from the RWops all data and concatinates all the frames
to one animation. The
SDL_RWops
    can be readonly but must support seeking.
    \param  NumFiles    Number of SDL_RWops
    \param  args        SDL_RWops for each wsa-File should be in this va_list.
(can be readonly)
*/
void Wsafile::readdata(int NumFiles, va_list args) {
    unsigned char** Filedata;
    Uint32** Index;
    Uint16* NumberOfFrames;
    bool* extended;

    if((Filedata = (unsigned char**) malloc(sizeof(unsigned char*) * NumFiles))
== NULL) {
        fprintf(stderr, "Wsafile::readdata(): Unable to allocate memory!\n");
        exit(EXIT_FAILURE);
    }

    ..........

       int WsaFilesize;
        RWop = va_arg(args,SDL_RWops*);   
        Filedata[i] = readfile(RWop,&WsaFilesize); <--- here crash, when not
the 1. method is called
before

Bye