[PATCH] D65374: [llvm-nm] Use same symbol types as gnu nm when --format=sysv

[Mike Pozulp via Phabricator via llvm-commits]

mmpozulp added a comment.

Should we match gnu nm exactly or is this enough? 
If we check all 16 possible bit-patterns of the 4-bit-wide symbol type (as in `format-sysv-type.test`) we can see that gnu nm prints the symbol_section and symbol_common symbols differently than we do. See (4) below for the differences.

(1) llvm-nm output **before** applying this patch

  Name                  Value           Class        Type         Size             Line  Section
  symbol_notype       |                |   U  |            NOTYPE|                |     |*UND*
  symbol_obj          |                |   U  |            OBJECT|                |     |*UND*
  symbol_function     |                |   U  |              FUNC|                |     |*UND*
  symbol_section      |                |   U  |           SECTION|                |     |*UND*
  symbol_file         |                |   U  |              FILE|                |     |*UND*
  symbol_common       |                |   U  |            COMMON|                |     |*COM*
  symbol_tls          |                |   U  |               TLS|                |     |*UND*
  symbol_unknown7     |                |   U  |                  |                |     |*UND*
  symbol_unknown8     |                |   U  |                  |                |     |*UND*
  symbol_unknown9     |                |   U  |                  |                |     |*UND*
  symbol_ifunc        |                |   U  |             IFUNC|                |     |*UND*
  os_specific10       |                |   U  |             IFUNC|                |     |*UND*
  os_specific11       |                |   U  |                  |                |     |*UND*
  os_specific12       |                |   U  |                  |                |     |*UND*
  proc_specific13     |                |   U  |                  |                |     |*UND*
  proc_specific14     |                |   U  |                  |                |     |*UND*
  proc_specific15     |                |   U  |                  |                |     |*UND*

(2) llvm-nm output **after** applying this patch

  Name                  Value           Class        Type         Size             Line  Section
  symbol_notype       |                |   U  |            NOTYPE|                |     |*UND*
  symbol_obj          |                |   U  |            OBJECT|                |     |*UND*
  symbol_function     |                |   U  |              FUNC|                |     |*UND*
  symbol_section      |                |   U  |           SECTION|                |     |*UND*
  symbol_file         |                |   U  |              FILE|                |     |*UND*
  symbol_common       |                |   U  |            COMMON|                |     |*COM*
  symbol_tls          |                |   U  |               TLS|                |     |*UND*
  symbol_unknown7     |                |   U  |      <unknown>: 7|                |     |*UND*
  symbol_unknown8     |                |   U  |      <unknown>: 8|                |     |*UND*
  symbol_unknown9     |                |   U  |      <unknown>: 9|                |     |*UND*
  symbol_ifunc        |                |   U  | <OS specific>: 10|                |     |*UND*
  os_specific10       |                |   U  | <OS specific>: 10|                |     |*UND*
  os_specific11       |                |   U  | <OS specific>: 11|                |     |*UND*
  os_specific12       |                |   U  | <OS specific>: 12|                |     |*UND*
  proc_specific13     |                |   U  |<processor specific>: 13|                |     |*UND*
  proc_specific14     |                |   U  |<processor specific>: 14|                |     |*UND*
  proc_specific15     |                |   U  |<processor specific>: 15|                |     |*UND*

(3) **gnu nm** (version 2.32) output

  Name                  Value           Class        Type         Size             Line  Section
  
  symbol_notype       |                |   U  |            NOTYPE|                |     |*UND*
  symbol_obj          |                |   U  |            OBJECT|                |     |*UND*
  symbol_function     |                |   U  |              FUNC|                |     |*UND*
  symbol_section      |                |   U  |                  |                |     |
  symbol_file         |                |   U  |              FILE|                |     |*UND*
  symbol_common       |                |   U  |            COMMON|                |     |*UND*
  symbol_tls          |                |   U  |               TLS|                |     |*UND*
  symbol_unknown7     |                |   U  |      <unknown>: 7|                |     |*UND*
  symbol_unknown8     |                |   U  |      <unknown>: 8|                |     |*UND*
  symbol_unknown9     |                |   U  |      <unknown>: 9|                |     |*UND*
  symbol_ifunc        |                |   U  | <OS specific>: 10|                |     |*UND*
  os_specific10       |                |   U  | <OS specific>: 10|                |     |*UND*
  os_specific11       |                |   U  | <OS specific>: 11|                |     |*UND*
  os_specific12       |                |   U  | <OS specific>: 12|                |     |*UND*
  proc_specific13     |                |   U  |<processor specific>: 13|                |     |*UND*
  proc_specific14     |                |   U  |<processor specific>: 14|                |     |*UND*
  proc_specific15     |                |   U  |<processor specific>: 15|                |     |*UND*

(4) diff llvm-nm gnu-nm

  $ diff llvmnm.out gnunm.out 
  5a6
  > 
  9c10
  < symbol_section      |                |   U  |           SECTION|                |     |*UND*
  ---
  > symbol_section      |                |   U  |                  |                |     |
  11c12
  < symbol_common       |                |   U  |            COMMON|                |     |*COM*
  ---
  > symbol_common       |                |   U  |            COMMON|                |     |*UND*


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D65374/new/

https://reviews.llvm.org/D65374