Re: 2.0.11 on OS X 10.9 / Xcode 5.1

[Taylan Ulrich Bayirli/Kammer <taylanbayirli@gmail.com>]

Mark H Weaver <mhw@netris.org> writes:

> Are you passing any optimization flags?  There are some, such as -Ofast,
> -ffast-math, -funsafe-math-optimizations, -fno-signed-zeros,
> -fassociative-math, and maybe some others that might result in this bug.

I don't pass any flags to ./configure or make, other than --prefix to
./configure.

I have several *PATH environment variables exported, but I guess that
wouldn't be relevant.

> Otherwise, I suspect that there's some optimization bug in the compiler
> you're using.  What exact version of GCC are you using?  These problems
> don't seem to be happening with GCC 4.8.2 on GNU/Linux systems.

bash-3.2$ gcc-mp-4.8 --version
gcc-mp-4.8 (MacPorts gcc48 4.8.2_0) 4.8.2


That aside, I noticed that passing CFLAGS+="-g" to make ends up
inhibiting the passing of -O2 to gcc-mp-4.8, so surely the issue lies
somewhere in there.  The -g flag is passed by default anyway, so the
only effect of the CFLAGS+="-g" on make is to inhibit -O2 after all.

I also figured out the problem with debug symbols: apparently the ld on
OS X doesn't carry over debug info from .o files to a generated .dylib
file.  Instead, one later runs dsymutil(1) on the .dylib file, which
gathers the debug info from the .o files and puts them into a .dSYM
directory; gdb even loads this automatically when it's in the standard
location.

The next roadblock I hit is that when I run gdb on the guile executable,
it doesn't seem to realize that the libguile dylib is loaded, so still
lacks the debug symbols from it.  (When I enter "info sharedlibrary" it
says "No shared libraries loaded at this time" although the Guile REPL
and all runs, so libguile is obviously loaded.)  I'll continue tomorrow
if I have time again at work.

Taylan