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https://github.com/jart/cosmopolitan.git
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01fd655097
Garbage collection will now happen on arm64 when a function returns, rather than kicking the can down the road to when the process exits. This change also does some code cleanup and incorporates suggestions
106 lines
3.6 KiB
ArmAsm
106 lines
3.6 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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.ftrace1
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__gc: .ftrace2
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#ifdef __x86_64__
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mov %fs:0,%rcx // __get_tls()
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mov 0x18(%rcx),%rcx // tls::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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nop
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#elif defined(__aarch64__)
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sub x8,x28,#1152 // __get_tls()
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ldr x9,[x8,0x18] // tib::garbages
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ldr x10,[x9] // g->i
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ldr x8,[x9,8] // g->p
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sub x10,x10,#1 //
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str x10,[x9] //
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sbfiz x10,x10,5,32 //
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add x8,x8,x10 // g->p+i
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ldr x9,[x8,#8] // g->p[i].fn
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ldr x10,[x8,#16] // g->p[i].arg
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ldr x11,[x8,#24] // g->p[i].ret
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stp x29,x11,[sp,-208]!
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mov x29,sp
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stp x0,x1,[sp,16]
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stp x2,x3,[sp,32]
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stp x4,x5,[sp,48]
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stp x6,x7,[sp,64]
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stp q0,q1,[sp,80]
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stp q2,q3,[sp,112]
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stp q4,q5,[sp,144]
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stp q6,q7,[sp,176]
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mov x1,x10
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bl CheckStackIsAligned
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blr x9
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ldp q6,q7,[sp,176]
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ldp q4,q5,[sp,144]
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ldp q2,q3,[sp,112]
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ldp q0,q1,[sp,80]
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ldp x6,x7,[sp,64]
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ldp x4,x5,[sp,48]
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ldp x2,x3,[sp,32]
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ldp x0,x1,[sp,16]
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ldp x29,x30,[sp],208
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ret
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#endif /* __x86_64__ */
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.endfn __gc,globl,hidden
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