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https://github.com/jart/cosmopolitan.git
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fad1279c61
If cosmo_dlopen() is linked on AMD64 then the runtime will switch to using %gs for thread-local storage. This eliminates the need for the imported symbol trampoline. It's now safer to pass function pointers back and forth with imported libraries. Your program gets recompiled at runtime to make it happen and the overhead is a few milliseconds.
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
#ifndef COSMOPOLITAN_LIBC_THREAD_TLS2_H_
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#define COSMOPOLITAN_LIBC_THREAD_TLS2_H_
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#include "libc/dce.h"
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#include "libc/thread/tls.h"
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COSMOPOLITAN_C_START_
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#if defined(__GNUC__) && defined(__x86_64__) && !defined(__STRICT_ANSI__)
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/**
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* Returns location of thread information block.
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*
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* This should be favored over __get_tls() for .privileged code that
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* can't be self-modified by __enable_tls().
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*/
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__funline struct CosmoTib *__get_tls_privileged(void) {
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char *tib, *lin = (char *)0x30;
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if (IsLinux() || IsFreebsd() || IsNetbsd() || IsOpenbsd() || IsMetal()) {
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if (!__tls_morphed) {
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asm("mov\t%%fs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
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} else {
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asm("mov\t%%gs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
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}
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} else {
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asm("mov\t%%gs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
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if (IsWindows()) {
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tib = *(char **)(tib + 0x1480 + __tls_index * 8);
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}
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}
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return (struct CosmoTib *)tib;
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}
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__funline struct CosmoTib *__get_tls_win32(void) {
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char *tib, *lin = (char *)0x30;
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asm("mov\t%%gs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
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tib = *(char **)(tib + 0x1480 + __tls_index * 8);
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return (struct CosmoTib *)tib;
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}
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__funline void __set_tls_win32(void *tls) {
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asm("mov\t%1,%%gs:%0" : "=m"(*((long *)0x1480 + __tls_index)) : "r"(tls));
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}
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#elif defined(__aarch64__)
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#define __get_tls_privileged() __get_tls()
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#define __get_tls_win32() ((struct CosmoTib *)0)
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#define __set_tls_win32(tls) (void)0
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#endif /* GNU x86-64 */
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COSMOPOLITAN_C_END_
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#endif /* COSMOPOLITAN_LIBC_THREAD_TLS2_H_ */
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