mirror of
https://github.com/jart/cosmopolitan.git
synced 2024-05-12 16:42:41 +00:00
a4b455185b
Renaming gc() to _gc() was a mistake since the better thing to do is put it behind the _COSMO_SOURCE macro. We need this change because I haven't wanted to use my amazing garbage collector ever since we renamed it. You now need to define _COSMO_SOURCE yourself when using amalgamation header and cosmocc users need to pass the -mcosmo flag to get the gc() function Some other issues relating to cancelation have been fixed along the way. We're also now putting cosmocc in a folder named `.cosmocc` so it can be more safely excluded by grep --exclude-dir=.cosmocc --exclude-dir=o etc.
99 lines
4 KiB
C
99 lines
4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/mem/gc.h"
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#include "libc/assert.h"
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#include "libc/intrin/likely.h"
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#include "libc/mem/mem.h"
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#include "libc/nexgen32e/gc.internal.h"
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#include "libc/nexgen32e/stackframe.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/thread/tls.h"
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forceinline bool PointerNotOwnedByParentStackFrame(struct StackFrame *frame,
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struct StackFrame *parent,
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void *ptr) {
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return !(((intptr_t)ptr > (intptr_t)frame) &&
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((intptr_t)ptr < (intptr_t)parent));
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}
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static void TeardownGc(void) {
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struct Garbages *g;
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struct CosmoTib *t;
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if (__tls_enabled) {
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t = __get_tls();
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if ((g = t->tib_garbages)) {
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// exit() currently doesn't use gclongjmp() like pthread_exit()
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// so we need to run the deferred functions manually.
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while (g->i) {
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--g->i;
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((void (*)(intptr_t))g->p[g->i].fn)(g->p[g->i].arg);
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}
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free(g->p);
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free(g);
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}
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}
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}
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__attribute__((__constructor__)) static void InitializeGc(void) {
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atexit(TeardownGc);
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}
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// add item to garbage shadow stack.
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// then rewrite caller's return address on stack.
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static void DeferFunction(struct StackFrame *frame, void *fn, void *arg) {
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int n2;
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struct Garbage *p2;
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struct Garbages *g;
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struct CosmoTib *t;
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t = __get_tls();
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g = t->tib_garbages;
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if (UNLIKELY(!g)) {
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if (!(g = malloc(sizeof(struct Garbages)))) notpossible;
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g->i = 0;
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g->n = 4;
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if (!(g->p = malloc(g->n * sizeof(struct Garbage)))) notpossible;
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t->tib_garbages = g;
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} else if (UNLIKELY(g->i == g->n)) {
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p2 = g->p;
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n2 = g->n + (g->n >> 1);
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if ((p2 = realloc(p2, n2 * sizeof(*p2)))) {
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g->p = p2;
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g->n = n2;
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} else {
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notpossible;
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}
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}
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g->p[g->i].frame = frame;
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g->p[g->i].fn = (intptr_t)fn;
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g->p[g->i].arg = (intptr_t)arg;
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g->p[g->i].ret = frame->addr;
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g->i++;
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frame->addr = (intptr_t)__gc;
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}
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// the gnu extension macros for gc / defer point here
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void __defer(void *rbp, void *fn, void *arg) {
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struct StackFrame *f, *frame = rbp;
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f = __builtin_frame_address(0);
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unassert(f->next == frame);
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unassert(PointerNotOwnedByParentStackFrame(f, frame, arg));
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DeferFunction(frame, fn, arg);
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}
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