mirror of
https://github.com/jart/cosmopolitan.git
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0e2b1bfeed
- 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
60 lines
2.8 KiB
ArmAsm
60 lines
2.8 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 tw=8 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/macros.internal.h"
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#include "libc/dce.h"
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#include "libc/notice.inc"
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nop
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// Invokes deferred function calls.
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//
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// This offers behavior similar to std::unique_ptr. Functions
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// overwrite their return addresses jumping here, and pushing
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// exactly one entry on the shadow stack below. Functions may
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// repeat that process multiple times, in which case the body
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// of this gadget loops and unwinds as a natural consequence.
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//
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// @param rax,rdx,xmm0,xmm1,st0,st1 is return value
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// @see test/libc/runtime/gc_test.c
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// @threadsafe
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__gc: mov %fs:0,%rcx # __get_tls()
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mov 0x18(%rcx),%rcx # cthread_t::garbages
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decl (%rcx) # ++g->i
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mov (%rcx),%r8d # r8 = g->i
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mov 8(%rcx),%r9 # r9 = g->p
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js 9f
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shl $5,%r8
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lea (%r9,%r8),%r8
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mov 8(%r8),%r9
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mov 16(%r8),%rdi
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push 24(%r8)
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push %rbp
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mov %rsp,%rbp
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sub $32,%rsp
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mov %rax,-8(%rbp)
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mov %rdx,-16(%rbp)
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movdqa %xmm0,-32(%rbp)
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call *%r9
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movdqa -32(%rbp),%xmm0
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mov -16(%rbp),%rdx
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mov -8(%rbp),%rax
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leave
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ret
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9: ud2
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.endfn __gc,globl,hidden
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