llvm-project

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# REQUIRES: x86
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# RUN: rm -rf %t; split-file %s %t
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## Test that we correctly handle the sdata4 DWARF pointer encoding. llvm-mc's
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## CFI directives always generate EH frames using the absptr (i.e. system
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## pointer size) encoding, but it is possible to hand-roll your own EH frames
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## that use the sdata4 encoding. For instance, libffi does this.
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos10.15 %t/sdata4.s -o %t/sdata4.o
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# RUN: %lld -lSystem %t/sdata4.o -o %t/sdata4
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# RUN: llvm-objdump --macho --syms --dwarf=frames %t/sdata4 | FileCheck %s
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# CHECK: SYMBOL TABLE:
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# CHECK: [[#%.16x,MAIN:]] g     F __TEXT,__text _main
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# CHECK: .eh_frame contents:
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# CHECK: 00000000 00000010 00000000 CIE
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# CHECK:   Format:                DWARF32
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# CHECK:   Version:               1
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# CHECK:   Augmentation:          "zR"
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# CHECK:   Code alignment factor: 1
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# CHECK:   Data alignment factor: 1
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# CHECK:   Return address column: 1
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# CHECK:   Augmentation data:     1B
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# CHECK:   DW_CFA_def_cfa: reg7 +8
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# CHECK:   CFA=reg7+8
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# CHECK: 00000014 00000010 00000018 FDE cie=00000000 pc=[[#%x,MAIN]]...[[#%x,MAIN+1]]
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# CHECK:   Format:       DWARF32
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# CHECK:   DW_CFA_GNU_args_size: +16
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# CHECK:   DW_CFA_nop:
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# CHECK:   0x[[#%x,MAIN]]: CFA=reg7+8
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#--- sdata4.s
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.globl  _main
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_main:
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  retq
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LmainEnd:
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.balign 4
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.section __TEXT,__eh_frame
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# Although we don't reference this EhFrame symbol directly, we must have at
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# least one non-local symbol in this section, otherwise llvm-mc generates bogus
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# subtractor relocations.
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EhFrame:
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LCieHdr:
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  .long LCieEnd - LCieStart
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LCieStart:
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  .long 0           # CIE ID
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  .byte 1           # CIE version
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  .ascii "zR\0"
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  .byte 1           # Code alignment
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  .byte 1           # Data alignment
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  .byte 1           # RA column
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  .byte 1           # Augmentation size
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  .byte 0x1b        # FDE pointer encoding (pcrel | sdata4)
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  .byte 0xc, 7, 8   # DW_CFA_def_cfa reg7 +8
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  .balign 4
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LCieEnd:
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LFdeHdr:
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  .long LFdeEnd - LFdeStart
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LFdeStart:
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  .long LFdeStart - LCieHdr
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  # The next two fields are longs instead of quads because of the sdata4
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  # encoding.
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  .long _main - .        # Function address
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  .long LmainEnd - _main # Function length
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  .byte 0
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  ## Insert DW_CFA_GNU_args_size to prevent ld64 from creating a compact unwind
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  ## entry to replace this FDE. Makes it easier for us to cross-check behavior
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  ## across the two linkers (LLD never bothers trying to synthesize compact
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  ## unwind if it is not already present).
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  .byte 0x2e, 0x10       # DW_CFA_GNU_args_size
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  .balign 4
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LFdeEnd:
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  .long 0 # terminator
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.subsections_via_symbols 
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