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This patch is glibc support for a PowerPC TLS optimization, inspired by Alexandre Oliva's TLS optimization for other processors, http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt In essence, this optimization uses a zero module id in the tls_index GOT entry to indicate that a TLS variable is allocated space in the static TLS area. A special plt call linker stub for __tls_get_addr checks for such a tls_index and if found, returns the offset immediately. The linker communicates the fact that the special __tls_get_addr stub is used by setting a bit in the dynamic tag DT_PPC64_OPT/DT_PPC_OPT. glibc communicates to the linker that this optimization is available by the presence of __tls_get_addr_opt. tst-tlsmod2.so is built with -Wl,--no-tls-get-addr-optimize for tst-tls-dlinfo, which otherwise would fail since it tests that no static tls is allocated. The ld option --no-tls-get-addr-optimize has been available since binutils-2.20 so doesn't need a configure test. * NEWS: Advertise TLS optimization. * elf/elf.h (R_PPC_TLSGD, R_PPC_TLSLD, DT_PPC_OPT, PPC_OPT_TLS): Define. (DT_PPC_NUM): Increment. * elf/dynamic-link.h (HAVE_STATIC_TLS): Define. (CHECK_STATIC_TLS): Use here. * sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_rela): Optimize TLS descriptors. * sysdeps/powerpc/powerpc64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/powerpc/dl-tls.c: New file. * sysdeps/powerpc/Versions: Add __tls_get_addr_opt. * sysdeps/powerpc/tst-tlsopt-powerpc.c: New tls test. * sysdeps/unix/sysv/linux/powerpc/Makefile: Add new test. Build tst-tlsmod2.so with --no-tls-get-addr-optimize. * sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist: Update. * sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist: Likewise.
53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
/* glibc test for __tls_get_addr optimization. */
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#include <stdio.h>
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#include "../../elf/tls-macros.h"
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#include "dl-tls.h"
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/* common 'int' variable in TLS. */
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COMMON_INT_DEF(foo);
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#define TEST_FUNCTION do_test ()
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static int
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do_test (void)
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{
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int result = 0;
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/* Get variable using general dynamic model. */
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int *ap = TLS_GD (foo);
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if (*ap != 0)
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{
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printf ("foo = %d\n", *ap);
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result = 1;
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}
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tls_index *tls_arg;
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#ifdef __powerpc64__
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register unsigned long thread_pointer __asm__ ("r13");
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asm ("addi %0,2,foo@got@tlsgd" : "=r" (tls_arg));
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#else
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register unsigned long thread_pointer __asm__ ("r2");
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asm ("bcl 20,31,1f\n1:\t"
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"mflr %0\n\t"
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"addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n\t"
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"addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n\t"
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"addi %0,%0,foo@got@tlsgd" : "=b" (tls_arg));
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#endif
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if (tls_arg->ti_module != 0)
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{
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printf ("tls_index not optimized, binutils too old?\n");
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result = 1;
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}
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else if (tls_arg->ti_offset + thread_pointer != (unsigned long) ap)
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{
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printf ("tls_index->ti_offset wrong value\n");
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result = 1;
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}
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return result;
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}
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#include "../../test-skeleton.c"
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