I mean come on, it's a free high-quality C compiler for almost any platform you can dig up! That's just awesome! C hasn't died or gone away since the 1980s, and being able to compile C for such a wide range of processors and platforms is great, in my opinion.
I agree with you that gcc is much less pleasant than LLVM+Clang, but to say that LLVM is better becauses it uses C++ everywhere is simply incorrect. In fact, using this kind of DSL for backend definitions is good design.
A large part of any LLVM backend is actually custom C++ code for matching and expanding patterns which the pattern matcher either can't or is unwilling to do (e.g. custom backend-specific DAG nodes). I direct you at this file:
https://github.com/llvm-mirror/llvm/blob/master/lib/Target/X...
github will give you a warning before loading it because that single C++ source file is over a megabyte...
Note that I am not complaining about the DSL, just how things are quite difficult to figure out (and untyped macros, as stated above).
But the simple fact remains that they did intentionally create hard to maintain code and spent several years rejecting patches that would clean up the monstrosity as a defense against people using GCC code in nonfree programs.
It's hard to trust their judgment now.
By way of example: I'm interested in the Broadcom Videocore IV processor, also known as the main processor on the Raspberry Pi. I bounced off both gcc and LLVM, and for much the same reason --- after getting the port about 75% complete I ran into blocking issues that I couldn't fix on my own and couldn't get enough assistance on the mailing lists to fix. Which is a shame. (I should point out that prior to that I did do a VC4 backend for the ACK compiler. It generates terrible, terrible but working code.)
I have run into commercial compilers which were easy to port, and generated good code, to boot. Volker Barthelman's vbcc even has a VC4 backend, which produces amazing code, and his compiler is a tiny fraction of the size of either gcc or LLVM! But it's not open source. Maybe one day we'll get a similarly good open source small compiler...
https://github.com/hermanhermitage/videocoreiv
(It's a beautiful processor. 32 registers, built in DSP, built in vector processing, some really elegant instruction design, dual core, and enough weirdness that writing good code is satisfying without being frustrating. No double precision float, alas, although it's got single precision, and for some bizarre reason there's no adc or sbc instruction which makes 64 bit arithmetic annoying.)
If you're interested in playing with it, you might also like a look at my half-finished pure-VC4-code boot loader here:
Stick it on an SD card, hook up a serial terminal, and it'll boot directly on the VC4 without even starting up the ARM.
I originally wanted to get Prex (a Minix-like microkernel OS with a Unix interface which doesn't need an MMU) running on the VC4, but I need an actual working compiler for that.
The only thing they changed was the arm cores and the memory subsystem.
It's certainly better to have an intermediate language and a modular design to compile to it and from it, but I thought this was introduced by LLVM and not gcc because (1.) compiler performance mattered more at the time, so it was better to couple everything to save some performance with dirty tricks, and (2.) people just hadn't realized that this was the right design. (The same way that it took time for the relational database abstraction to come around and replace the tendency for each program to use its custom internal database.)
Is there any specific reason to believe that gcc's design was influenced by licensing reasons?
I'm just as weird as you.
I am hoping to be able to devote some time this year to cross-pollinate with David Malcolm's work to get libgccjit working on GNU Octave:
It's possible to do autoconf-style checks in other build systems, but not as easily. I don't know why most build systems seem to ignore the wisdom of autoconf.
On a more serious note, the whole "I feel <x> about GCC" has a certain challenge about it as GCC isn't a compiler so much as it is a very long story. I think I have pretty much had every emotion you can have with respect to GCC, whether it was admiration for supporting an obscure platform, hatred for a gratuitous interdependency on a library, or respect for a particularly clean compilation. But over its life it has gone in many directions and gone through many theories of how a compiler should be written, and some of those chapters are very dark indeed.
I was also amused that there is a link chain to the 'kissed a girl' email that Bryan Cantrill (CTO of Joyent) wrote back in 1996. Proof that the Internet really really doesn't like sarcasm.