cosmopolitan/libc/runtime/defer.greg.c

64 lines
3.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/arraylist.h"
#include "libc/assert.h"
#include "libc/bits/bits.h"
#include "libc/calls/calls.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/gc.h"
#include "libc/runtime/gc.h"
#include "libc/runtime/runtime.h"
forceinline bool PointerNotOwnedByParentStackFrame(struct StackFrame *frame,
struct StackFrame *parent,
void *ptr) {
return !(((intptr_t)ptr > (intptr_t)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) {
struct StackFrame *frame2;
/*
* To avoid an API requiring dlmalloc dependency, say:
* defer(free_s, &ptr_not_owned_by_current_frame)
* Rather than:
* defer(weak(free), ptr)
*/
if (!arg) return;
frame2 = __builtin_frame_address(0);
assert(frame2->next == frame);
assert(PointerNotOwnedByParentStackFrame(frame2, frame, arg));
if (append(&g_garbage,
(&(const struct Garbage){frame->next, (intptr_t)fn, (intptr_t)arg,
frame->addr})) != -1) {
atomic_store(&frame->addr, (intptr_t)&CollectGarbage);
} else {
abort();
}
}