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 ↗

(On Diff #52250)

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

lld/trunk/ELF/Driver.cpp

bool elf::link(ArrayRef<const char *> Args, raw_ostream &Error) {
   Config = &C;
   Driver = &D;
   Script = &LS;
   Driver->main(Args);
   return !HasError;
 }
 
 static std::pair<ELFKind, uint16_t> parseEmulation(StringRef S) {
+  if (S.endswith("_fbsd"))
+    S = S.drop_back(5);
   if (S == "elf32btsmip")
     return {ELF32BEKind, EM_MIPS};
   if (S == "elf32ltsmip")
     return {ELF32LEKind, EM_MIPS};
-  if (S == "elf32ppc" || S == "elf32ppc_fbsd")
+  if (S == "elf32ppc")
     return {ELF32BEKind, EM_PPC};
-  if (S == "elf64ppc" || S == "elf64ppc_fbsd")
+  if (S == "elf64ppc")
     return {ELF64BEKind, EM_PPC64};
   if (S == "elf_i386")
     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")

lld/trunk/test/ELF/emulation.s

 # X86-NEXT:   HeaderSize: 52
 # X86-NEXT:   ProgramHeaderEntrySize: 32
 # X86-NEXT:   ProgramHeaderCount:
 # X86-NEXT:   SectionHeaderEntrySize: 40
 # X86-NEXT:   SectionHeaderCount:
 # X86-NEXT:   StringTableSectionIndex:
 # X86-NEXT: }
 
+# RUN: llvm-mc -filetype=obj -triple=i686-unknown-freebsd %s -o %tx86fbsd
+# RUN: ld.lld -m elf_i386_fbsd %tx86fbsd -o %t2x86_fbsd
+# RUN: llvm-readobj -file-headers %t2x86_fbsd | FileCheck --check-prefix=X86FBSD %s
+# RUN: ld.lld %tx86fbsd -o %t3x86fbsd
+# RUN: llvm-readobj -file-headers %t3x86fbsd | FileCheck --check-prefix=X86FBSD %s
+# X86FBSD:      ElfHeader {
+# X86FBSD-NEXT:   Ident {
+# X86FBSD-NEXT:     Magic: (7F 45 4C 46)
+# X86FBSD-NEXT:     Class: 32-bit (0x1)
+# X86FBSD-NEXT:     DataEncoding: LittleEndian (0x1)
+# X86FBSD-NEXT:     FileVersion: 1
+# X86FBSD-NEXT:     OS/ABI: FreeBSD (0x9)
+# X86FBSD-NEXT:     ABIVersion: 0
+# X86FBSD-NEXT:     Unused: (00 00 00 00 00 00 00)
+# X86FBSD-NEXT:   }
+# X86FBSD-NEXT:   Type: Executable (0x2)
+# X86FBSD-NEXT:   Machine: EM_386 (0x3)
+# X86FBSD-NEXT:   Version: 1
+# X86FBSD-NEXT:   Entry:
+# X86FBSD-NEXT:   ProgramHeaderOffset: 0x34
+# X86FBSD-NEXT:   SectionHeaderOffset:
+# X86FBSD-NEXT:   Flags [ (0x0)
+# X86FBSD-NEXT:   ]
+# X86FBSD-NEXT:   HeaderSize: 52
+# X86FBSD-NEXT:   ProgramHeaderEntrySize: 32
+# X86FBSD-NEXT:   ProgramHeaderCount:
+# X86FBSD-NEXT:   SectionHeaderEntrySize: 40
+# X86FBSD-NEXT:   SectionHeaderCount:
+# X86FBSD-NEXT:   StringTableSectionIndex:
+# X86FBSD-NEXT: }
+
 # RUN: llvm-mc -filetype=obj -triple=powerpc64-unknown-linux %s -o %tppc64
 # RUN: ld.lld -m elf64ppc %tppc64 -o %t2ppc64
 # RUN: llvm-readobj -file-headers %t2ppc64 | FileCheck --check-prefix=PPC64 %s
 # RUN: ld.lld %tppc64 -o %t3ppc64
 # RUN: llvm-readobj -file-headers %t3ppc64 | FileCheck --check-prefix=PPC64 %s
 # PPC64:      ElfHeader {
 # PPC64-NEXT:   Ident {
 # PPC64-NEXT:     Magic: (7F 45 4C 46)