Re: [wgcc-dev] BUG - POSIX build

[Duft M. <Mar...@sa...>]

Cool! ;o)

It just came into my mind, that the environment stuff additionally uses =
a fixed buffer (4096 chars) somewhere. This is fixed in the next version =
of wgcc, but you should have the old sources...

So wgcc now works fine with a cc build?

Cheers, Markus=20

-----Original Message-----
From: Jerker B=E4ck [mailto:jer...@ho...]=20
Sent: Thursday, October 19, 2006 1:44 PM
To: int...@li...
Cc: Duft Markus
Subject: BUG - POSIX build

I finally got the posix debugger working - yess!

And finally found the bug in wgcc preventing the MS build.

The current wgcc posix build will not even make it to main(). It throws =
an exception during construction of the context instance of class =
Context located in  Context.cpp(700):

    Context::Context()
    ...
more exactly here:
      paths.c =3D Environment::getPaths(COMPILER_C);
=3D> stop - stack buffer overrun.

The output looks like this:

---------------------------------------------------

  *** A stack buffer overrun occurred in ?=01:

This is usually the result of a memory copy to a local buffer or =
structure where the size is not properly calculated/checked.
If this bug ends up in the shipping product, it could be a severe =
security hole.
The stack trace should show the guilty function (the function directly =
above __report_gsfailure).
 *** enter .exr 49ACA2A0 for the exception record
 *** then kb to get the faulting stack

Windows has triggered a breakpoint in wgcc.SUA.exe.

This may be due to a corruption of the heap, and indicates a bug in =
wgcc.SUA.exe or any of the DLLs it has loaded.

The output window may have more diagnostic information

---------------------------------------------------

At this point _mainCRTStartup have not been started yet:

Program flow =3D>
>wgcc.SUA.exe!__PosixProcessStartup(int calledFromldso=3D0, _startupData =
*
incomingStartup=3D0x00000000)
>wgcc.SUA.exe!_init(int argc=3D1, char * * argv=3D0x00010640, char * *
environ=3D0x00010648)
>wgcc.SUA.exe!_cinit()
>wgcc.SUA.exe!_initterm(void (void)* * pfbegin=3D0x00462094, void =
(void)*=20
>*
pfend=3D0x004620f0)
>wgcc.SUA.exe!wgcc::`dynamic initializer for 'context''()  Line 703	C++
>wgcc.SUA.exe!wgcc::Context::Context()  Line 35	C++

code in Environment.cpp is executed  =3D> exception, stack buffer =
overrun.

>wgcc.SUA.exe!_mainCRTStartup()
>wgcc.SUA.exe!main(int argc=3D1, char * * argv=3D0x00010640)  Line 100	=
C++
 =09
The construction and memory allocation done in Environment.cpp should be =
delayed until we enter main()

I suggest a Context::init() function from main() like this:

extern "C"
int __cdecl main(int argc, char ** argv) {
    wgcc::CommandLine::OptionManager manager(wgcc::options, false);
    if(!wgcc::context.init()) return ERROR_CODE;
   ...

and

bool Environment::getPaths(Destination dest, std::list<std::string>& =
paths); bool Context::init() {
   // Supply existing list by reference
   if(!Environment::getPaths(COMPILER_C, paths.c)) return false;
   if(!Environment::getPaths(COMPILER_CPP, paths.cpp)) return false;
   if(!Environment::getPaths(LINKER, paths.linker)) return false;
   return true;
}

When I applied this fix I got a working build from cc and VS2005

I attach a code analysis build log FYI

Note: The dynamic_cast's mentioned earlier is still turned into =
static_cast's

regards Jerker