diff options
Diffstat (limited to 'sysdeps/x86_64/start.S')
| -rw-r--r-- | sysdeps/x86_64/start.S | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S index 1374974307..354d2e6ec7 100644 --- a/sysdeps/x86_64/start.S +++ b/sysdeps/x86_64/start.S @@ -1,5 +1,5 @@ /* Startup code compliant to the ELF x86-64 ABI. - Copyright (C) 2001-2016 Free Software Foundation, Inc. + Copyright (C) 2001-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Andreas Jaeger <aj@suse.de>, 2001. @@ -96,27 +96,28 @@ ENTRY (_start) which grow downwards). */ pushq %rsp -#ifdef SHARED +#ifdef PIC /* Pass address of our own entry points to .fini and .init. */ mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP mov main@GOTPCREL(%rip), %RDI_LP - - /* Call the user's main function, and exit with its value. - But let the libc call main. */ - call __libc_start_main@PLT #else /* Pass address of our own entry points to .fini and .init. */ mov $__libc_csu_fini, %R8_LP mov $__libc_csu_init, %RCX_LP mov $main, %RDI_LP +#endif /* Call the user's main function, and exit with its value. - But let the libc call main. */ - call __libc_start_main -#endif + But let the libc call main. Since __libc_start_main in + libc.so is called very early, lazy binding isn't relevant + here. Use indirect branch via GOT to avoid extra branch + to PLT slot. In case of static executable, ld in binutils + 2.26 or above can convert indirect branch into direct + branch. */ + call *__libc_start_main@GOTPCREL(%rip) hlt /* Crash if somehow `exit' does return. */ END (_start) |