lld/test/ELF/gc-sections-startstop.s

   1 ## Check that group members are retained or discarded as a unit.
   2
   3 # REQUIRES: x86
   4
   5 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
   6 # RUN: ld.lld %t.o --gc-sections -o %t
   7 # RUN: llvm-readelf -s %t | FileCheck %s
   8
   9 # RUN: echo ".global __start___data; __start___data:" > %t2.s
  10 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %t2.s -o %t2.o
  11 # RUN: ld.lld -shared %t2.o --soname=t2 -o %t2.so
  12 # RUN: ld.lld %t.o --gc-sections -o %t2 %t2.so
  13 # RUN: llvm-readelf -s %t2 | FileCheck %s
  14
  15 ## The referenced __data is retained.
  16 # CHECK:     [[#%x,ADDR:]] {{.*}} __start___data
  17 # CHECK:     [[#ADDR + 8]] {{.*}} __stop___data
  18 ## __libc_atexit is retained even if there is no reference, as a workaround for
  19 ## glibc<2.34 (BZ #27492).
  20 # CHECK:     [[#%x,ADDR:]] {{.*}} __start___libc_atexit
  21 # CHECK:     [[#ADDR + 8]] {{.*}} __stop___libc_atexit
  22 # CHECK:     _start
  23 # CHECK:     f
  24 # CHECK-NOT: g
  25
  26 ## If -z nostart-stop-gc, sections whose names are C identifiers are retained by
  27 ## __start_/__stop_ references.
  28 # RUN: ld.lld %t.o %t2.so --gc-sections -z nostart-stop-gc -o %t3
  29 # RUN: llvm-readelf -s %t3 | FileCheck %s --check-prefix=NOGC
  30 # NOGC:     [[#%x,ADDR:]] {{.*}} __start___data
  31 # NOGC:     [[#ADDR + 16]] {{.*}} __stop___data
  32
  33 .weak __start___data
  34 .weak __stop___data
  35 .weak __start___libc_atexit
  36 .weak __stop___libc_atexit
  37
  38 .section .text,"ax",@progbits
  39 .global _start
  40 _start:
  41   .quad __start___data - .
  42   .quad __stop___data - .
  43   .quad __start___libc_atexit - .
  44   .quad __stop___libc_atexit - .
  45   call f
  46
  47 .section __data,"axG",@progbits,f
  48 .quad 0
  49
  50 .section .text.f,"axG",@progbits,f
  51 .global f
  52 f:
  53   nop
  54
  55 .section __data,"axG",@progbits,g
  56 .quad 0
  57
  58 .section .text.g,"axG",@progbits,g
  59 .global g
  60 g:
  61   nop
  62
  63 .section __libc_atexit,"a",@progbits
  64 .quad 0