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https://github.com/jart/cosmopolitan.git
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Make garbage collection thread safe
- You can now use _gc(malloc()) in multithreaded programs - This change fixes a bug where fork() on NT disabled TLS - Fixed TLS code morphing on XNU/NT, for R8-R15 registers
This commit is contained in:
Justine Tunney
parent
571c2c3c69
commit
0e2b1bfeed
37 changed files with 310 additions and 189 deletions
24
libc/mem/_gc_free.c
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24
libc/mem/_gc_free.c
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@ -0,0 +1,24 @@
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 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/mem.h"
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#include "libc/runtime/gc.h"
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void _gc_free(void *p) {
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free(p);
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}
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@ -1,85 +0,0 @@
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 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/assert.h"
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#include "libc/intrin/likely.h"
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#include "libc/intrin/weaken.h"
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#include "libc/calls/calls.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/runtime/gc.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.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 __garbage_destroy(void) {
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if (weaken(free)) {
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weaken(free)(__garbage.p);
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}
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bzero(&__garbage, sizeof(__garbage));
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}
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void __deferer(struct StackFrame *frame, void *fn, void *arg) {
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size_t n2;
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struct Garbage *p2;
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if (UNLIKELY(__garbage.i == __garbage.n)) {
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p2 = __garbage.p;
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n2 = __garbage.n + (__garbage.n >> 1);
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if (__garbage.p != __garbage.initmem) {
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if (!weaken(realloc)) return;
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if (!(p2 = weaken(realloc)(p2, n2 * sizeof(*p2)))) return;
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} else {
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if (!weaken(malloc)) return;
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if (!(p2 = weaken(malloc)(n2 * sizeof(*p2)))) return;
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memcpy(p2, __garbage.p, __garbage.n * sizeof(*p2));
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atexit(__garbage_destroy);
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}
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__garbage.p = p2;
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__garbage.n = n2;
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}
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__garbage.p[__garbage.i].frame = frame;
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__garbage.p[__garbage.i].fn = (intptr_t)fn;
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__garbage.p[__garbage.i].arg = (intptr_t)arg;
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__garbage.p[__garbage.i].ret = frame->addr;
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__garbage.i++;
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frame->addr = (intptr_t)__gc;
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}
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/**
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* Adds destructor to garbage shadow stack.
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*
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* @param frame is passed automatically by wrapper macro
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* @param fn takes one argument
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* @param arg is passed to fn(arg)
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* @return arg
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*/
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void __defer(struct StackFrame *frame, void *fn, void *arg) {
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struct StackFrame *f;
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if (!arg) return;
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f = __builtin_frame_address(0);
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assert(__garbage.n);
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assert(f->next == frame);
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assert(PointerNotOwnedByParentStackFrame(f, frame, arg));
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__deferer(frame, fn, arg);
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}
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@ -16,9 +16,93 @@
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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/assert.h"
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#include "libc/intrin/kprintf.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/gettls.h"
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#include "libc/nexgen32e/stackframe.h"
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#include "libc/runtime/gc.h"
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#include "libc/nexgen32e/threaded.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/thread.h"
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static inline 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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int i;
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cthread_t tls;
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struct Garbages *g;
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if (__tls_enabled) {
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tls = (cthread_t)__get_tls();
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if ((g = tls->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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cthread_t tls;
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struct Garbage *p2;
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struct Garbages *g;
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TlsIsRequired();
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tls = (cthread_t)__get_tls();
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g = tls->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)))) {
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kprintf("malloc failed\n");
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notpossible;
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}
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tls->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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assert(f->next == frame);
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assert(PointerNotOwnedByParentStackFrame(f, frame, arg));
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DeferFunction(frame, fn, arg);
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}
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/**
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* Frees memory when function returns.
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* @warning do not realloc() with gc()'d pointer
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* @warning be careful about static keyword due to impact of inlining
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* @note you should use -fno-omit-frame-pointer
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* @threadsafe
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*/
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void *(_gc)(void *thing) {
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struct StackFrame *frame;
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frame = __builtin_frame_address(0);
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__deferer(frame->next, _weakfree, thing);
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DeferFunction(frame->next, _weakfree, thing);
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return thing;
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}
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* @warning do not realloc() with gc()'d pointer
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* @warning be careful about static keyword due to impact of inlining
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* @note you should use -fno-omit-frame-pointer
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* @threadsafe
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*/
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void *(_defer)(void *fn, void *arg) {
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struct StackFrame *frame;
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frame = __builtin_frame_address(0);
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__deferer(frame->next, fn, arg);
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DeferFunction(frame->next, fn, arg);
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return arg;
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}
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