lld: accept and ignore _fbsd suffix in emulation name

[emaste]

Summary

elf_i386_fbsd is used in the FreeBSD/amd64 build for the 32-bit compat libs.

[davide]

This is good. Is it possible to add a testcase?

[ruiu]

LGTM

ELF/Driver.cpp

59

This patch makes me wonder if we need "elf_x86_64_fbsd".

[ruiu]

Or you can drop "_fbsd" by adding this piece of code at beginning of this function.

if (S.endswith("_fbsd"))
  S = S.drop_back(5);

[emaste]

just ignore _fbsd suffix as suggested by @ruiu

[ruiu]

Just curious. Do you know the meaining of "_fbsd" suffix in other linkers?

[emaste]

In D18661#388529, @ruiu wrote:

Just curious. Do you know the meaining of "_fbsd" suffix in other linkers?

As far as I can tell it just sets the OS/ABI to FreeBSD. In practice all input ELF objects I've seen have the OS/ABI set already and lld just passes it through, so no special treatment is necessary.

[ruiu]

LGTM

ELF/Driver.cpp

static std::pair<ELFKind, uint16_t> parseEmulation(StringRef S) {
   if (S == "elf32btsmip")
     return {ELF32BEKind, EM_MIPS};
   if (S == "elf32ltsmip")
     return {ELF32LEKind, EM_MIPS};
   if (S == "elf32ppc" || S == "elf32ppc_fbsd")
     return {ELF32BEKind, EM_PPC};
   if (S == "elf64ppc" || S == "elf64ppc_fbsd")
     return {ELF64BEKind, EM_PPC64};
-  if (S == "elf_i386")
+  if (S == "elf_i386" || S == "elf_i386_fbsd")
     return {ELF32LEKind, EM_386};
   if (S == "elf_x86_64")
     return {ELF64LEKind, EM_X86_64};
   if (S == "aarch64linux")
     return {ELF64LEKind, EM_AARCH64};
   if (S == "i386pe" || S == "i386pep" || S == "thumb2pe")
     error("Windows targets are not supported on the ELF frontend: " + S);
   else
     error("unknown emulation: " + S);
   return {ELFNoneKind, 0};