NetBSD/external/bsd/elftoolchain
riastradh ad49149131 elftoolchain: Be consistent about which ELF header files we use.
1. For tools that use elftoolchain: always use elftoolchain's
   elfdefinitions.h.  Don't even think about looking at the host's
   sys/exec_elf.h, which makes no sense and should never happen.

   (ELF tools that don't use elftoolchain, like m68k-elf2coff,
   continue to use nbincludes/sys/exec_elf.h.  But no more nbincludes
   hacks in elftoolchain.)

2. For kernel components (solaris, zfs, dtrace): always use
   sys/exec_elf.h, even in Solaris components via sys/elf.h.
   elfdefinitions.h is not wired up in the kernel build at all.

3. For most userland components that involve libelf: use
   elfdefinitions.h via libelf header files (libelf.h, gelf.h).

   libdtrace in particular requires _all_ R_* reloc type definitions,
   but sys/exec_elf.h brings in only the _current machine's_ R_*
   reloc type definitions.  (While here: Use uintptr_t instead of
   Elf_Addr for pointer-to-integer cast, since Elf_Addr is MD and
   provided only by sys/exec_elf.h, not by elfdefinitions.h.)

   And most userland components using libelf don't rely on any
   properties of the current machine from sys/exec_elf.h, so they can
   use libelf's elfdefinition.h.

   Exceptions:

   - dtrace drti.c relies on link.h -> link_elf.h -> sys/exec_elf.h,
     but it also relies on sys/dtrace.h -> sys/elf.h ->
     elfdefinitions.h like other userland components using sys/elf.h.

   - kdump-ioctl.c uses sys/exec_elf.h directly and sys/dtrace.h ->
     sys/elf.h -> elfdefinitions like other userland components using
     sys/elf.h.

   - t_ptrace_wait.c (via t_ptrace_core_wait.h) uses libelf to parse
     core files, but relies on sys/exec_elf.h for struct
     netbsd_elfcore_procinfo.

   None of these exceptions needs all R_* reloc type definitions, so
   as a workaround, we can just suppress libelf's elfdefinitions.h by
   defining _SYS_ELFDEFINITIONS_H_ and use sys/exec_elf.h in these
   exceptions.

And undo the whole BUILTIN_ELF_HEADERS mistake.  This was:

- half bogus workarounds for missing build_install dependencies in
  tools/Makefile, which are no longer missing now, and
- half futile attempt to use src/sys/sys/exec_elf.h via nbincludes in
  tools involving libelf instead of libelf's elfdefinitions.h, which
  collides.

Longer-term, we may wish to unify sys/exec_elf.h and libelf's
elfdefinitions.h, so we don't have to play these games.

But at least now the games are limited to three .c files (one of
which is generated by Makefile.ioctl-c), rather than haphazardly
applied tree-wide by monstrous kludges in widely used .h files with
broken hackarounds to get the tools build lurching to completion.
2024-04-01 18:33:22 +00:00
..
common Add ${_MKTARGET_CREATE} 2024-03-27 21:55:08 +00:00
dist elftoolchain: Be consistent about which ELF header files we use. 2024-04-01 18:33:22 +00:00
lib elftoolchain: Be consistent about which ELF header files we use. 2024-04-01 18:33:22 +00:00
Makefile Traverse the Elftoolchain 'common' module before 2021-04-07 20:32:54 +00:00
README Use README to import 2024-03-03 17:41:48 +00:00

README

#!/bin/sh
$ svn checkout https://svn.code.sf.net/p/elftoolchain/code/trunk elftoolchain-code
$ mkdir dist.new
$ dist/tools/netbsd-base-system-import.sh -m common -m libdwarf -m libelf -s elftoolchain-code -d dist.new
$ cd dist.new
cvs -d cvs.netbsd.org import src/external/bsd/elftoolchain FreeBSD rXXXX