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thradams
Preprocessing SDL sources with cake
Hello!
Over at SDL, we're currently debating on how to support older platforms whose compilers do not support c99 and newer. Think about WatCom, Windows 95 , OS/2, ...
SDL's source code is currently c99, with a public c89 api.
The main issue with c89 is our use of declarations after statements (-Wdeclaration-after-statement gcc warning).
I was thinking about using cake as a source preprocessor to transform SDL sources on the fly into c89 code.
SDL uses CMake as build system, so I think -DCMAKE_C_COMPILER_LAUNCHER= might do the trick.
Using a wrapper, configuring SDL succeeds but building fails due to failing static_assert's. Is there something we can do about this?
`cake-wrapper.py`
#!/usr/bin/env python
# Cake wrapper for compiler
import os
from pathlib import Path
import shlex
import subprocess
import sys
import tempfile
DEBUG_WRAPPER = os.getenv("DEBUG_CAKE_WRAPPER") is not None
CAKE = os.getenv("CAKE") or "cake"
def main() -> int:
compiler_cmd = []
cake_args = []
for arg in sys.argv[1:]:
if arg.startswith("-I"):
cake_args.append(arg)
elif arg.startswith("-D"):
cake_args.append(arg)
elif arg.startswith("-U"):
cake_args.append(arg)
for arg in sys.argv[1:]:
if arg.endswith(".c"):
c = Path(arg)
cake_c = Path(tempfile.gettempdir()) / c.with_suffix(".cake.c").name
cake_cmd = [CAKE] + cake_args + [f"-I{c.parent}", str(c), "-o", str(cake_c)]
compiler_cmd.append(f"-I{c.parent}")
if DEBUG_WRAPPER:
print(f"Running cake: '{shlex.join(cake_cmd)}'", file=sys.stderr)
sys.stderr.flush()
result = subprocess.call(cake_cmd)
if result != 0:
print(f"Cake failed: {shlex.join(cake_cmd)}", file=sys.stderr)
sys.stderr.flush()
return result
arg = str(cake_c)
compiler_cmd.append(arg)
if DEBUG_WRAPPER:
print(f"Running compiler: '{shlex.join(compiler_cmd)}'", file=sys.stderr)
sys.stderr.flush()
return subprocess.call(compiler_cmd)
if __name__ == "__main__":
raise SystemExit(main())
Reproducer:
git clone https://github.com/libsdl-org/SDL /tmp/SDL --depth 1
cmake -S /tmp/SDL -B /tmp/SDL-build -DCMAKE_COMPILER=/usr/bin/gcc "-DCMAKE_C_COMPILERR_LAUNCHER=python;/path/to/cake-wrapper.py"
cmake --build /tmp/SDL-build
Is there something we can do about the errors?
cake errors of a single SDL soruce
Cake 0.12.35 (GCC)
/home/maarten/projects/SDL/src/libm/e_atan2.c
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1175:1: error C1060: static_assert failed "sizeof(bool) == 1"
1175 |SDL_COMPILE_TIME_ASSERT(bool_size, sizeof(bool) == 1)static_assert(sizeof(_Bool)==1,"sizeof(bool) == 1");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1176:1: error C1060: static_assert failed "sizeof(Uint8) == 1"
1176 |SDL_COMPILE_TIME_ASSERT(uint8_size, sizeof(Uint8) == 1)static_assert(sizeof(Uint8)==1,"sizeof(Uint8) == 1");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1177:1: error C1060: static_assert failed "sizeof(Sint8) == 1"
1177 |SDL_COMPILE_TIME_ASSERT(sint8_size, sizeof(Sint8) == 1)static_assert(sizeof(Sint8)==1,"sizeof(Sint8) == 1");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1178:1: error C1060: static_assert failed "sizeof(Uint16) == 2"
1178 |SDL_COMPILE_TIME_ASSERT(uint16_size, sizeof(Uint16) == 2)static_assert(sizeof(Uint16)==2,"sizeof(Uint16) == 2");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1179:1: error C1060: static_assert failed "sizeof(Sint16) == 2"
1179 |SDL_COMPILE_TIME_ASSERT(sint16_size, sizeof(Sint16) == 2)static_assert(sizeof(Sint16)==2,"sizeof(Sint16) == 2");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1180:1: error C1060: static_assert failed "sizeof(Uint32) == 4"
1180 |SDL_COMPILE_TIME_ASSERT(uint32_size, sizeof(Uint32) == 4)static_assert(sizeof(Uint32)==4,"sizeof(Uint32) == 4");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1181:1: error C1060: static_assert failed "sizeof(Sint32) == 4"
1181 |SDL_COMPILE_TIME_ASSERT(sint32_size, sizeof(Sint32) == 4)static_assert(sizeof(Sint32)==4,"sizeof(Sint32) == 4");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1182:1: error C1060: static_assert failed "sizeof(Uint64) == 8"
1182 |SDL_COMPILE_TIME_ASSERT(uint64_size, sizeof(Uint64) == 8)static_assert(sizeof(Uint64)==8,"sizeof(Uint64) == 8");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1183:1: error C1060: static_assert failed "sizeof(Sint64) == 8"
1183 |SDL_COMPILE_TIME_ASSERT(sint64_size, sizeof(Sint64) == 8)static_assert(sizeof(Sint64)==8,"sizeof(Sint64) == 8");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1185:1: error C1060: static_assert failed "sizeof(Uint64) <= sizeof(unsigned long long)"
1185 |SDL_COMPILE_TIME_ASSERT(uint64_longlong, sizeof(Uint64) <= sizeof(unsigned long long))static_assert(sizeof(Uint64)<=sizeof(unsignedlonglong),"sizeof(Uint64) <= sizeof(unsigned long long)");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1186:1: error C1060: static_assert failed "sizeof(size_t) <= sizeof(unsigned long long)"
1186 |SDL_COMPILE_TIME_ASSERT(size_t_longlong, sizeof(size_t) <= sizeof(unsigned long long))static_assert(sizeof(size_t)<=sizeof(unsignedlonglong),"sizeof(size_t) <= sizeof(unsigned long long)");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1193:1: error C1060: static_assert failed "sizeof(SDL_alignment_test) == (2 * sizeof(void *))"
1193 |SDL_COMPILE_TIME_ASSERT(struct_alignment, sizeof(SDL_alignment_test) == (2 * sizeof(void *)))static_assert(sizeof(SDL_alignment_test)==(2*sizeof(void*)),"sizeof(SDL_alignment_test) == (2 * sizeof(void *))");
| ~~~~~~~~~~~~~
/home/maarten/projects/SDL/include/SDL3/SDL_stdinc.h:1213:1: error C1060: static_assert failed "sizeof(SDL_DUMMY_ENUM) == sizeof(int)"
1213 |SDL_COMPILE_TIME_ASSERT(enum, sizeof(SDL_DUMMY_ENUM) == sizeof(int))static_assert(sizeof(SDL_DUMMY_ENUM)==sizeof(int),"sizeof(SDL_DUMMY_ENUM) == sizeof(int)");
| ~~~~~~~~~~~~~
/usr/include/signal.h:369:57: error C0970: expected token '{', got ';'
369 | ("Use the signal and sigprocmask functions instead");
| ~
14 errors 0 warnings 0 notes
1 files in 0.65 seconds
