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Interview with Mark Mitchel, GCC's Release Engineer
ICC-Rocks writes "In light of the imminent release of the first 'stable' version of GCC version 3, OSNews features an interview with Mark Mitchel, GCC's Release Engineer. They are talking about GCC 3.x, the future and the competition."
gcc 2.96 is actually more standards compliant than any other version
of gcc released at the time Red Hat made this decision (3.0 is even more compliant, but not as stable yet).
It may not be "standards compliant" as in "what most others
are shipping", but 2.96 is almost fully ISO C99 and ISO C++ 98
compliant, unlike any previous version of gcc.
gcc 2.96 has more complete support for C++. Older versions of gcc could
handle only a very limited subset of C++.
Earlier versions of g++ often had problems with templates and other
valid C++ constructs.
Most of gcc 2.96's perceived "bugs" are actually broken code
that older gccs accepted because they were not standards compliant - or, using
an alternative term to express the same thing, buggy.
A C or C++ compiler that doesn't speak the standardized C language is
a bug, not a feature.
In the initial version of gcc 2.96, there were a couple of other bugs.
All known ones have been fixed in the version from updates - and the version
that is in the current beta version of Red Hat Linux. The bugs in the initial
version don't make the whole compiler broken, though. There has never been
a 100% bug free compiler, or any other 100% bug free non-trivial program.
The current version can be taken from Red Hat Linux 7.2. It will work
without changes on prior 7.x releases of Red Hat Linux.
Since a lot of people claim 2.96 is buggy because of the accusations
found in MPlayer documentation, I have
included the facts that led them to incorrectly believe that 2.96 is buggy
here.
gcc 2.96 generates better, more optimized code.
gcc 2.96 supports all architectures Red Hat is currently supporting,
including ia64. No other compiler can do this. Having to maintain different
compilers for every different architecture is a development (find a bug, then
fix it 4 times), QA and support nightmare.
The binary incompatibility issues are not as bad as some people and
companies make you believe.
First of all, they affect dynamically linked C++ code only.
If you don't use C++, you aren't affected. If you use C++ and link statically,
you aren't affected.
If you don't mind depending on a current glibc, you might also want to
link statically to c++ libraries while linking dynamically to glibc and other
C libraries you're using:
g++ -o test test.cc -Wl,-Bstatic -lstdc++ -Wl,-Bdynamic
(Thanks to Pavel Roskin for pointing this
out)
Second, the same issues appear with every major release of gcc
so far. gcc 2.7.x C++ is not binary compatible with gcc 2.8.x. gcc 2.8.x C++
is not binary compatible with egcs 1.0.x. egcs 1.0.x C++ is not binary
compatible with egcs 1.1.x. egcs 1.1.x C++ is not binary compatible with
gcc 2.95. gcc 2.95 C++ is not binary compatible with gcc 3.0.
Besides, it can easily be circumvented. Either link statically, or
simply distribute libstdc++ with your program and install it if necessary.
Since it has a different soname, it can coexist with other libstdc++ versions
without causing any problems.
Red Hat Linux 7 also happens to be the first Linux distributions using
the current version of glibc, 2.2.x. This update is not binary compatible with
older distributions either (unless you update glibc - there's nothing that
prevents you from updating libstdc++ at the same time), so complaining about
gcc's new C++ ABI breaking binary compatibility is pointless. If you want
to distribute something binary-only, link it statically and it will run
everywhere.
Someone has to be the first to take a step like this. If nobody dared
to make a change because nobody else is doing it, we'd all still be using
gcc 1.0, COBOL or ALGOL. No wait, all of those were new at some point...
gcc 3.0, the current so-called "stable" release (released quite
some time after Red Hat released gcc 2.96-RH), fixes some problems, but
introduces many others - for example, gcc 3.0.1 can't compile KDE 2.2
correctly due to bugs in gcc 3.0.x's implementation in multiple inheritance
in C++.
Until another set of 3.0.x updates is released, I still claim 2.96 is
the best compiler yet.