Expose public garbage collector API for C language

You can now do epic things like this:

    puts(_gc(xasprintf("%d", 123)));

The _gc() API is shorthand for _defer() which works like Go's keyword:

    const char *s = xasprintf("%d", 123);
    _defer(free, s);
    puts(s);

Be sure to always use -fno-omit-frame-pointer which makes code fast too.

Enjoy! See also #114
This commit is contained in:
Justine Tunney 2021-03-08 10:56:09 -08:00
parent 0ad609268f
commit 33e8fc8687
26 changed files with 192 additions and 182 deletions

30
libc/runtime/gc.h Normal file
View file

@ -0,0 +1,30 @@
#ifndef COSMOPOLITAN_LIBC_RUNTIME_GC_H_
#define COSMOPOLITAN_LIBC_RUNTIME_GC_H_
#include "libc/calls/calls.h"
#include "libc/nexgen32e/stackframe.h"
#include "libc/runtime/runtime.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
void *_gc(void *) hidden;
void *_defer(void *, void *) hidden;
void __defer(struct StackFrame *, void *, void *) hidden;
void __deferer(struct StackFrame *, void *, void *) hidden;
void _gclongjmp(jmp_buf, int) nothrow wontreturn;
#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
#define _gc(THING) _defer((void *)_weakfree, (void *)(THING))
#define _defer(FN, ARG) \
({ \
autotype(ARG) Arg = (ARG); \
/* prevent weird opts like tail call */ \
asm volatile("" : "+g"(Arg) : : "memory"); \
__defer((struct StackFrame *)__builtin_frame_address(0), FN, Arg); \
asm volatile("" : "+g"(Arg) : : "memory"); \
Arg; \
})
#endif /* defined(__GNUC__) && !defined(__STRICT_ANSI__) */
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_RUNTIME_GC_H_ */