lld/test/MachO/eh-frame-sdata4.s

   1 # REQUIRES: x86
   2 # RUN: rm -rf %t; split-file %s %t
   3
   4 ## Test that we correctly handle the sdata4 DWARF pointer encoding. llvm-mc's
   5 ## CFI directives always generate EH frames using the absptr (i.e. system
   6 ## pointer size) encoding, but it is possible to hand-roll your own EH frames
   7 ## that use the sdata4 encoding. For instance, libffi does this.
   8
   9 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos10.15 %t/sdata4.s -o %t/sdata4.o
  10 # RUN: %lld -lSystem %t/sdata4.o -o %t/sdata4
  11 # RUN: llvm-objdump --macho --syms --dwarf=frames %t/sdata4 | FileCheck %s
  12
  13 # CHECK: SYMBOL TABLE:
  14 # CHECK: [[#%.16x,MAIN:]] g     F __TEXT,__text _main
  15
  16 # CHECK: .eh_frame contents:
  17 # CHECK: 00000000 00000010 00000000 CIE
  18 # CHECK:   Format:                DWARF32
  19 # CHECK:   Version:               1
  20 # CHECK:   Augmentation:          "zR"
  21 # CHECK:   Code alignment factor: 1
  22 # CHECK:   Data alignment factor: 1
  23 # CHECK:   Return address column: 1
  24 # CHECK:   Augmentation data:     1B
  25 # CHECK:   DW_CFA_def_cfa: reg7 +8
  26 # CHECK:   CFA=reg7+8
  27
  28 # CHECK: 00000014 00000010 00000018 FDE cie=00000000 pc=[[#%x,MAIN]]...[[#%x,MAIN+1]]
  29 # CHECK:   Format:       DWARF32
  30 # CHECK:   DW_CFA_GNU_args_size: +16
  31 # CHECK:   DW_CFA_nop:
  32 # CHECK:   0x[[#%x,MAIN]]: CFA=reg7+8
  33
  34 #--- sdata4.s
  35 .globl  _main
  36 _main:
  37   retq
  38 LmainEnd:
  39
  40 .balign 4
  41 .section __TEXT,__eh_frame
  42 # Although we don't reference this EhFrame symbol directly, we must have at
  43 # least one non-local symbol in this section, otherwise llvm-mc generates bogus
  44 # subtractor relocations.
  45 EhFrame:
  46 LCieHdr:
  47   .long LCieEnd - LCieStart
  48 LCieStart:
  49   .long 0           # CIE ID
  50   .byte 1           # CIE version
  51   .ascii "zR\0"
  52   .byte 1           # Code alignment
  53   .byte 1           # Data alignment
  54   .byte 1           # RA column
  55   .byte 1           # Augmentation size
  56   .byte 0x1b        # FDE pointer encoding (pcrel | sdata4)
  57   .byte 0xc, 7, 8   # DW_CFA_def_cfa reg7 +8
  58   .balign 4
  59 LCieEnd:
  60
  61 LFdeHdr:
  62   .long LFdeEnd - LFdeStart
  63 LFdeStart:
  64   .long LFdeStart - LCieHdr
  65   # The next two fields are longs instead of quads because of the sdata4
  66   # encoding.
  67   .long _main - .        # Function address
  68   .long LmainEnd - _main # Function length
  69   .byte 0
  70   ## Insert DW_CFA_GNU_args_size to prevent ld64 from creating a compact unwind
  71   ## entry to replace this FDE. Makes it easier for us to cross-check behavior
  72   ## across the two linkers (LLD never bothers trying to synthesize compact
  73   ## unwind if it is not already present).
  74   .byte 0x2e, 0x10       # DW_CFA_GNU_args_size
  75   .balign 4
  76 LFdeEnd:
  77
  78   .long 0 # terminator
  79
  80 .subsections_via_symbols