lld/test/ELF/linkerscript/symbol-assign-type.s

   1 # REQUIRES: x86
   2 ## Keep st_type for simple assignment (`alias = aliasee`). This property is
   3 ## desired on some targets, where symbol types can affect relocation processing
   4 ## (e.g. Thumb interworking). However, the st_size field should not be retained
   5 ## because some tools use st_size=0 as a heuristic to detect aliases. With any
   6 ## operation, it can be argued that the new symbol may not be of the same type,
   7 ## so reset st_type to STT_NOTYPE.
   8
   9 ## NOTE: GNU ld retains st_type for many operations.
  10
  11 # RUN: split-file %s %t
  12 # RUN: llvm-mc -filetype=obj -triple=x86_64 %t/main.s -o %t.o
  13 # RUN: ld.lld -T %t/a.lds %t.o -o %t1
  14 # RUN: llvm-readelf -s %t1 | FileCheck %s
  15
  16 # CHECK:      Size Type   Bind   Vis     Ndx Name
  17 # CHECK:         1 FUNC   GLOBAL DEFAULT   1 _start
  18 # CHECK:         0 FUNC   GLOBAL DEFAULT   1 retain1
  19 # CHECK-NEXT:    0 FUNC   GLOBAL DEFAULT   1 retain2
  20 # CHECK-NEXT:    0 NOTYPE GLOBAL DEFAULT   1 drop1
  21 # CHECK-NEXT:    0 NOTYPE GLOBAL DEFAULT ABS drop2
  22 # CHECK-NEXT:    0 NOTYPE GLOBAL DEFAULT ABS drop3
  23
  24 # RUN: ld.lld --defsym 'retain=_start' --defsym 'drop=_start+0' %t.o -o %t2
  25 # RUN: llvm-readelf -s %t2 | FileCheck %s --check-prefix=DEFSYM
  26
  27 # DEFSYM:        0 FUNC   GLOBAL DEFAULT   1 retain
  28 # DEFSYM-NEXT:   0 NOTYPE GLOBAL DEFAULT   1 drop
  29
  30 #--- a.lds
  31 retain1 = _start;
  32 retain2 = 1 ? _start : 0;
  33
  34 ## Reset to STT_NOTYPE if any operation is performed,
  35 ## even if the operation is an identity function.
  36 drop1 = _start + 0;
  37 drop2 = 0 ? _start : 1;
  38 drop3 = -_start;
  39
  40 #--- main.s
  41 .globl _start
  42 .type _start, @function
  43 _start:
  44   ret
  45 .size _start, 1