tcc: update tcc to latest version, fix stdatomic

[kbkpbot]

As the v/thirdparty/tcc/README.md said, "This is a prebuild tcc (git://repo.or.cz/tinycc.git), cut at commit:
806b3f9 from 2021-03-17
which is the last good commit found by bisecting, that does not cause vlib/sync/channel_close_test.v to wait indefinitely ."

It seems that the atomic_load/atomic_store of TCC do not include memory barriers. (Windows version have MemoryBarrier() )
By adding atomic_thread_fence(memory_order_acquire)/atomic_thread_fence(memory_order_release) before/after atomic_load/atomic_store, it can be solved.
And, latest TCC stdatomic.h already support a generic interface like gcc/clang.

NOTE, to use this PR, tcc should update to latest version.

[spytheman]

Wow, that will be very nice indeed!
Thank you for investigating 🙇🏻‍♂️ .

[medvednikov]

Thanks @kbkpbot! This is some great work you did.

[spytheman]

I've rebuilt thirdparty/tcc's thirdparty-linux-amd64 branch, so that it has
tcc version 0.9.28rc 2024-02-05 HEAD@105d70f7 (x86_64 Linux) (your latest commit in tcc's mob branch).
I'm still testing it, but so far, it works very well.
I'll push the changes to the thirdparty-linux-amd64 branch soon, then I will update the other prebuilt branches too.

[spytheman]

>          OK: STBI load does not leak with GC on, when loading images multiple times (use < 10MB)
>          OK: V can crun a script, that lacks a .vsh extension
>          OK: V can run a script, that lacks a .vsh extension
Tue Feb  6 13:15:32 EET 2024
all tests done
CPU: 1159.63s   Real: 691.84s   Elapsed: 11:31.84       RAM: 474564KB   v_fast_all_tests

VFLAGS="-cc tcc" ./v test-all passed locally.

I've pushed the branch to https://github.com/vlang/tccbin .

[spytheman]

As a bonus, with the new tcc build, the executable sizes are now significantly smaller 🥳, while the compile speed is ~ the same, or even slightly better:

Before:

#0 13:26:16 ᛋ master /v/oo❱thirdparty/tcc/tcc.exe --version
tcc version 0.9.27 (x86_64 Linux)
#0 13:26:24 ᛋ master /v/oo❱
#0 13:26:25 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.10s      Real: 0.12s     Elapsed: 0:00.12        RAM: 40832KB    ./v examples/hello_world.v
#0 13:26:29 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.10s      Real: 0.11s     Elapsed: 0:00.11        RAM: 40900KB    ./v examples/hello_world.v
#0 13:26:29 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.10s      Real: 0.11s     Elapsed: 0:00.11        RAM: 40876KB    ./v examples/hello_world.v
#0 13:26:30 ᛋ master /v/oo❱xtime ./v examples/2048/
CPU: 0.34s      Real: 0.36s     Elapsed: 0:00.36        RAM: 102784KB   ./v examples/2048/
#0 13:26:33 ᛋ master /v/oo❱xtime ./v examples/2048/
CPU: 0.34s      Real: 0.36s     Elapsed: 0:00.36        RAM: 102840KB   ./v examples/2048/
#0 13:26:34 ᛋ master /v/oo❱xtime ./v examples/2048/
CPU: 0.34s      Real: 0.35s     Elapsed: 0:00.35        RAM: 102812KB   ./v examples/2048/
#0 13:26:34 ᛋ master /v/oo❱
#0 13:26:35 ᛋ master /v/oo❱
#0 13:26:35 ᛋ master /v/oo❱ls -la examples/hello_world examples/2048/2048
-rwxrwxr-x 1 delian delian 3632932 Feb  6 13:26 examples/2048/2048
-rwxrwxr-x 1 delian delian  794988 Feb  6 13:26 examples/hello_world
#0 13:26:38 ᛋ master /v/oo❱

After:

#0 13:27:01 ᛋ master /v/oo❱thirdparty/tcc/tcc.exe --version
tcc version 0.9.28rc 2024-02-05 HEAD@105d70f7 (x86_64 Linux)
#0 13:27:04 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.11s      Real: 0.12s     Elapsed: 0:00.12        RAM: 40860KB    ./v examples/hello_world.v
#0 13:27:09 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.11s      Real: 0.12s     Elapsed: 0:00.12        RAM: 40884KB    ./v examples/hello_world.v
#0 13:27:10 ᛋ master /v/oo❱xtime ./v examples/hello_world.v
CPU: 0.10s      Real: 0.11s     Elapsed: 0:00.11        RAM: 40884KB    ./v examples/hello_world.v
#0 13:27:10 ᛋ master /v/oo❱xtime ./v examples/2048/
^[[ACPU: 0.31s  Real: 0.33s     Elapsed: 0:00.33        RAM: 102756KB   ./v examples/2048/
#0 13:27:18 ᛋ master /v/oo❱xtime ./v examples/2048/
CPU: 0.32s      Real: 0.34s     Elapsed: 0:00.34        RAM: 102788KB   ./v examples/2048/
#0 13:27:19 ᛋ master /v/oo❱xtime ./v examples/2048/
CPU: 0.31s      Real: 0.32s     Elapsed: 0:00.32        RAM: 102804KB   ./v examples/2048/
#0 13:27:19 ᛋ master /v/oo❱
#0 13:27:20 ᛋ master /v/oo❱ls -la examples/hello_world examples/2048/2048
-rwxrwxr-x 1 delian delian 2804512 Feb  6 13:27 examples/2048/2048
-rwxrwxr-x 1 delian delian  686584 Feb  6 13:27 examples/hello_world
#0 13:27:23 ᛋ master /v/oo❱

[kbkpbot]

Something interesting, after apply this PR, v self compile time become 8x slower.....
(just overwrite the v/thirdparty/stdatomic/nix/atomic.h)
Before apply PR:

~/github/kbkpbot/v/thirdparty/stdatomic/nix$ time v self
V self compiling ...
V built successfully as executable "v".

real    0m1.169s
user    0m1.321s
sys     0m0.127s

After apply PR:

~/github/kbkpbot/v/thirdparty/stdatomic/nix$ time v self
V self compiling ...
V built successfully as executable "v".

real    0m9.105s
user    0m8.566s
sys     0m0.401s

Sorry, I found that is because TCC compile fail, and try CC instead.
I will find out what was happened.

[medvednikov]

Yes, exactly. When tcc fails, V falls back to gcc/clang.

It's the same error as before:

./v1.exe -no-parallel -o v2.exe -cc tcc -no-retry-compilation cmd/v
vlib/v/gen/c/cheaders.v:849:69: error: this number has unsuitable digit `u`
  847 | #ifndef __vinix__
  848 | // convert any 64 bit pseudo random numbers to uniform distribution [0,1). It can be combined with wyrand, wyhash64 or wyhash.
  849 | static inline double wy2u01(uint64_t r){ const double _wynorm=1.0/(1ull<<52); return (r>>12)*_wynorm;}
      |                                                                     ^
  850 | 
  851 | // convert any 64 bit pseudo random numbers to APPROXIMATE Gaussian distribution. It can be combined with wyrand, wyhash64 or wyhash.
make: *** [GNUmakefile:114: all] Error 1