readelf: Add support for RISC-V specific e_flags

[mhorne]

Summary

The RISC-V ELF header definitions can be found at: https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#file-header

Test Plan

Sample outputs from readelf -h:

ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            NONE
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           RISC-V
  Version:                           0x1
  Entry point address:               0x120aa
  Start of program headers:          64 (bytes into file)
  Start of section headers:          15976 (bytes into file)
  Flags:                             0x5, double-float ABI, RVC
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         7
  Size of section headers:           64 (bytes)
  Number of section headers:         26
  Section header string table index: 25

[mhorne]

Update the flag messages to match GNU's readelf.
Include a check for soft-float ABI.

[markj]

Approved.

[mhorne]

Use EF_RISCV_FLOAT_ABI_MASK instead of EF_RISCV_FLOAT_ABI_QUAD

[mhorne]

What is the process for committing changes to elftoolchain? Should I commit them to FreeBSD and make separate submissions for the upstream repo?

contrib/elftoolchain/common/elfdefinitions.h

431 ↗

(On Diff #59066)

I'm not sure if this file needs an EF_RISCV_FLOAT_ABI_SOFT as well. Honestly I'm not sure what uses these definitions since readelf uses sys/elf_common.h. Is this still worth keeping in the same commit?

[markj]

In D20767#449340, @mhorne wrote:

What is the process for committing changes to elftoolchain? Should I commit them to FreeBSD and make separate submissions for the upstream repo?

You can just commit to FreeBSD for now. @emaste asked me to submit my recent changes as commits against https://github.com/elftoolchain/elftoolchain so I guess you could do that too, but maybe see if he chimes in here first.

contrib/elftoolchain/common/elfdefinitions.h

431 ↗

(On Diff #59066)

I don't think it hurts to keep it.

I'm not sure what these are used for. They might be useful on other operating systems which don't have an equivalent system header.

[emaste]

Ideally we'd commit changes upstream and then import a new version with a latency of several days or a week or so but that process seems to be somewhat slow right now so I'm fine with just committing to FreeBSD and then having @markj or me work on upstreaming changes in batches.

That said if you do have changes in a GitHub fork (and submit pull requests or just point me at them) I can cherry pick and git-svn commit.

[jkoshy_users.sourceforge.net]

Patches sent to elftoolchain-developers and tickets filed on SF are
usually responded to within a few days (usually by the weekend).

Regards,
Joseph Koshy

[mhorne]

Add EF_RISCV_FLOAT_ABI_MASK to elfdefinitions.h.

[mhorne]

contrib/elftoolchain/common/elfdefinitions.h

431 ↗

(On Diff #59066)

You were right, it needs to be defined here to build the upstream elftoolchain, even on FreeBSD.

[markj]

Approved.