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Expose public garbage collector API for C language

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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
Download patch file Download diff file Expand all files Collapse all files

34
libc/mem/defer.greg.c
View file

@ -31,23 +31,9 @@ forceinline bool PointerNotOwnedByParentStackFrame(struct StackFrame *frame,
((intptr_t)ptr < (intptr_t)parent));
}
/**
* Adds destructor to garbage shadow stack.
*
* @param frame is passed automatically by wrapper macro
* @param fn takes one argument
* @param arg is passed to fn(arg)
* @return arg
*/
void __defer(struct StackFrame *frame, void *fn, void *arg) {
void __deferer(struct StackFrame *frame, void *fn, void *arg) {
size_t n2;
struct Garbage *p2;
struct StackFrame *f2;
if (!arg) return;
f2 = __builtin_frame_address(0);
assert(__garbage.n);
assert(f2->next == frame);
assert(PointerNotOwnedByParentStackFrame(f2, frame, arg));
if (UNLIKELY(__garbage.i == __garbage.n)) {
n2 = __garbage.n + (__garbage.n >> 1);
p2 = malloc(n2 * sizeof(*__garbage.p));
@ -63,3 +49,21 @@ void __defer(struct StackFrame *frame, void *fn, void *arg) {
__garbage.i++;
frame->addr = (intptr_t)__gc;
}
/**
* Adds destructor to garbage shadow stack.
*
* @param frame is passed automatically by wrapper macro
* @param fn takes one argument
* @param arg is passed to fn(arg)
* @return arg
*/
void __defer(struct StackFrame *frame, void *fn, void *arg) {
struct StackFrame *f2;
if (!arg) return;
f2 = __builtin_frame_address(0);
assert(__garbage.n);
assert(f2->next == frame);
assert(PointerNotOwnedByParentStackFrame(f2, frame, arg));
__deferer(frame, fn, arg);
}