[ELF][MIPS] Remove support for linking microMIPS 64-bit code

[atanasyan]

Summary

Remove support for linking microMIPS 64-bit code because this kind of ISA is rarely used and unsupported by LLVM.

[grimar]

LGTM.

ELF/Arch/MipsArchTree.cpp

79

This seems to be easier just to check all the files and inline, maybe?

 for (const FileFlags &F : Files) {
     if (Config->Is64 && F.Flags & EF_MIPS_MICROMIPS)
       error("linking microMIPS 64-bit files is unsupported: " + toString(F.File));
...

Up to you, though.

[atanasyan]

ELF/Arch/MipsArchTree.cpp

79

The loop iterates through all input files except the first one because initial purpose of the loop was to to check compatibility between files and the first file used as a reference. That's why I have to write the checking code before and inside the loop. But I think we can iterate through all the files including the first one. In that case we check compatibility between the first file and itself, but it's not a problem.

I'm going to commit this patch as is (thanks for review) and after that refactor this code.

[grimar]

ELF/Arch/MipsArchTree.cpp

79

Yes, that is what I meant. Checking the first file with itself should not be a problem.

ELF/Arch/Mips.cpp

RelExpr MIPS<ELFT>::getRelExpr(RelType Type, const Symbol &S,
   case R_MICROMIPS_PC26_S1:
     return R_PLT_PC;
   case R_MIPS_HI16:
   case R_MIPS_LO16:
   case R_MIPS_HIGHER:
   case R_MIPS_HIGHEST:
   case R_MICROMIPS_HI16:
   case R_MICROMIPS_LO16:
-  case R_MICROMIPS_HIGHER:
-  case R_MICROMIPS_HIGHEST:
     // R_MIPS_HI16/R_MIPS_LO16 relocations against _gp_disp calculate
     // offset between start of function and 'gp' value which by default
     // equal to the start of .got section. In that case we consider these
     // relocations as relative.
     if (&S == ElfSym::MipsGpDisp)
       return R_MIPS_GOT_GP_PC;
     if (&S == ElfSym::MipsLocalGp)
       return R_MIPS_GOT_GP;
     LLVM_FALLTHROUGH;
   case R_MIPS_32:
   case R_MIPS_64:
   case R_MIPS_GOT_OFST:
   case R_MIPS_SUB:
   case R_MIPS_TLS_DTPREL_HI16:
   case R_MIPS_TLS_DTPREL_LO16:
   case R_MIPS_TLS_DTPREL32:
   case R_MIPS_TLS_DTPREL64:
   case R_MIPS_TLS_TPREL_HI16:
   case R_MIPS_TLS_TPREL_LO16:
   case R_MIPS_TLS_TPREL32:
   case R_MIPS_TLS_TPREL64:
-  case R_MICROMIPS_GOT_OFST:
-  case R_MICROMIPS_SUB:
   case R_MICROMIPS_TLS_DTPREL_HI16:
   case R_MICROMIPS_TLS_DTPREL_LO16:
   case R_MICROMIPS_TLS_TPREL_HI16:
   case R_MICROMIPS_TLS_TPREL_LO16:
     return R_ABS;
   case R_MIPS_PC32:
   case R_MIPS_PC16:
   case R_MIPS_PC19_S2:
RelExpr MIPS<ELFT>::getRelExpr(RelType Type, const Symbol &S,
   case R_MICROMIPS_GOT16:
     if (S.isLocal())
       return R_MIPS_GOT_LOCAL_PAGE;
     LLVM_FALLTHROUGH;
   case R_MIPS_CALL16:
   case R_MIPS_GOT_DISP:
   case R_MIPS_TLS_GOTTPREL:
   case R_MICROMIPS_CALL16:
-  case R_MICROMIPS_GOT_DISP:
   case R_MICROMIPS_TLS_GOTTPREL:
     return R_MIPS_GOT_OFF;
   case R_MIPS_CALL_HI16:
   case R_MIPS_CALL_LO16:
   case R_MIPS_GOT_HI16:
   case R_MIPS_GOT_LO16:
   case R_MICROMIPS_CALL_HI16:
   case R_MICROMIPS_CALL_LO16:
   case R_MICROMIPS_GOT_HI16:
   case R_MICROMIPS_GOT_LO16:
     return R_MIPS_GOT_OFF32;
   case R_MIPS_GOT_PAGE:
-  case R_MICROMIPS_GOT_PAGE:
     return R_MIPS_GOT_LOCAL_PAGE;
   case R_MIPS_TLS_GD:
   case R_MICROMIPS_TLS_GD:
     return R_MIPS_TLSGD;
   case R_MIPS_TLS_LDM:
   case R_MICROMIPS_TLS_LDM:
     return R_MIPS_TLSLD;
   case R_MIPS_NONE:
calculateMipsRelChain(uint8_t *Loc, RelType Type, uint64_t Val) {
   RelType Type2 = (Type >> 8) & 0xff;
   RelType Type3 = (Type >> 16) & 0xff;
   if (Type2 == R_MIPS_NONE && Type3 == R_MIPS_NONE)
     return std::make_pair(Type, Val);
   if (Type2 == R_MIPS_64 && Type3 == R_MIPS_NONE)
     return std::make_pair(Type2, Val);
   if (Type2 == R_MIPS_SUB && (Type3 == R_MIPS_HI16 || Type3 == R_MIPS_LO16))
     return std::make_pair(Type3, -Val);
-  if (Type2 == R_MICROMIPS_SUB &&
-      (Type3 == R_MICROMIPS_HI16 || Type3 == R_MICROMIPS_LO16))
-    return std::make_pair(Type3, -Val);
   error(getErrorLocation(Loc) + "unsupported relocations combination " +
         Twine(Type));
   return std::make_pair(Type & 0xff, Val);
 }
 
 template <class ELFT>
 void MIPS<ELFT>::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
   const endianness E = ELFT::TargetEndianness;
void MIPS<ELFT>::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
   case R_MIPS_GOT_LO16:
   case R_MIPS_GOT_OFST:
   case R_MIPS_LO16:
   case R_MIPS_PCLO16:
   case R_MIPS_TLS_DTPREL_LO16:
   case R_MIPS_TLS_TPREL_LO16:
     writeValue<E>(Loc, Val, 16, 0);
     break;
-  case R_MICROMIPS_GOT_DISP:
-  case R_MICROMIPS_GOT_PAGE:
   case R_MICROMIPS_GPREL16:
   case R_MICROMIPS_TLS_GD:
   case R_MICROMIPS_TLS_LDM:
     checkInt(Loc, Val, 16, Type);
     writeShuffleValue<E>(Loc, Val, 16, 0);
     break;
   case R_MICROMIPS_CALL16:
   case R_MICROMIPS_CALL_LO16:
-  case R_MICROMIPS_GOT_OFST:
   case R_MICROMIPS_LO16:
   case R_MICROMIPS_TLS_DTPREL_LO16:
   case R_MICROMIPS_TLS_GOTTPREL:
   case R_MICROMIPS_TLS_TPREL_LO16:
     writeShuffleValue<E>(Loc, Val, 16, 0);
     break;
   case R_MICROMIPS_GPREL7_S2:
     checkInt(Loc, Val, 7, Type);
case R_MICROMIPS_TLS_TPREL_HI16:
     writeShuffleValue<E>(Loc, Val + 0x8000, 16, 16);
     break;
   case R_MIPS_HIGHER:
     writeValue<E>(Loc, Val + 0x80008000, 16, 32);
     break;
   case R_MIPS_HIGHEST:
     writeValue<E>(Loc, Val + 0x800080008000, 16, 48);
     break;
-  case R_MICROMIPS_HIGHER:
-    writeShuffleValue<E>(Loc, Val + 0x80008000, 16, 32);
-    break;
-  case R_MICROMIPS_HIGHEST:
-    writeShuffleValue<E>(Loc, Val + 0x800080008000, 16, 48);
-    break;
   case R_MIPS_JALR:
   case R_MICROMIPS_JALR:
     // Ignore this optimization relocation for now
     break;
   case R_MIPS_PC16:
     checkAlignment(Loc, Val, 4, Type);
     checkInt(Loc, Val, 18, Type);
     writeValue<E>(Loc, Val, 16, 2);
case R_MICROMIPS_PC23_S2:
     break;
   default:
     error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
   }
 }
 
 template <class ELFT> bool MIPS<ELFT>::usesOnlyLowPageBits(RelType Type) const {
   return Type == R_MIPS_LO16 || Type == R_MIPS_GOT_OFST ||
-         Type == R_MICROMIPS_LO16 || Type == R_MICROMIPS_GOT_OFST;
+         Type == R_MICROMIPS_LO16;
 }
 
 // Return true if the symbol is a PIC function.
 template <class ELFT> bool elf::isMipsPIC(const Defined *Sym) {
   if (!Sym->isFunc())
     return false;
 
   if (Sym->StOther & STO_MIPS_PIC)

ELF/Arch/MipsArchTree.cpp

 }
 
 static StringRef getNanName(bool IsNan2008) {
   return IsNan2008 ? "2008" : "legacy";
 }
 
 static StringRef getFpName(bool IsFp64) { return IsFp64 ? "64" : "32"; }
 
+static void rejectMicroMips64(const FileFlags &F) {
+  if (Config->Is64 && F.Flags & EF_MIPS_MICROMIPS)
+    error("linking microMIPS 64-bit files is unsupported: " + toString(F.File));
+}
+
 static void checkFlags(ArrayRef<FileFlags> Files) {
   uint32_t ABI = Files[0].Flags & (EF_MIPS_ABI | EF_MIPS_ABI2);
   bool Nan = Files[0].Flags & EF_MIPS_NAN2008;
   bool Fp = Files[0].Flags & EF_MIPS_FP64;
 
+  rejectMicroMips64(Files[0]);
+
   for (const FileFlags &F : Files.slice(1)) {
+    rejectMicroMips64(F);
+
     uint32_t ABI2 = F.Flags & (EF_MIPS_ABI | EF_MIPS_ABI2);
     if (ABI != ABI2)
       error("target ABI '" + getAbiName(ABI) + "' is incompatible with '" +
             getAbiName(ABI2) + "': " + toString(F.File));
 
     bool Nan2 = F.Flags & EF_MIPS_NAN2008;
     if (Nan != Nan2)
       error("target -mnan=" + getNanName(Nan) + " is incompatible with -mnan=" +

test/ELF/mips-micro-got64.s

-# REQUIRES: mips
-# Check microMIPS GOT relocations for N64 ABI.
-
-# microMIPS 64-bit is unsupported by LLVM starting from r335057.
-# But such code can be generated by GCC. Mark this test as XFAIL
-# while decide to drop microMIPS 64-bit support from LLD too or
-# use binary inputs for the test.
-# XFAIL: *
-
-# RUN: llvm-mc -filetype=obj -triple=mips64-unknown-linux -mattr=micromips \
-# RUN:         %s -o %t1.o
-# RUN: llvm-mc -filetype=obj -triple=mips64-unknown-linux -mattr=micromips \
-# RUN:         %S/Inputs/mips-dynamic.s -o %t2.o
-# RUN: ld.lld %t2.o -shared -o %t.so
-# RUN: ld.lld %t1.o %t.so -o %t.exe
-# RUN: llvm-readobj -mips-plt-got %t.exe | FileCheck %s
-
-# CHECK:      Local entries [
-# CHECK-NEXT:   Entry {
-# CHECK-NEXT:     Address:
-# CHECK-NEXT:     Access: -32736
-# CHECK-NEXT:     Initial: 0x30000
-# CHECK-NEXT:   }
-# CHECK-NEXT:   Entry {
-# CHECK-NEXT:     Address:
-# CHECK-NEXT:     Access: -32728
-# CHECK-NEXT:     Initial: 0x40000
-# CHECK-NEXT:   }
-# CHECK-NEXT: ]
-# CHECK-NEXT: Global entries [
-# CHECK-NEXT:   Entry {
-# CHECK-NEXT:     Address:
-# CHECK-NEXT:     Access: -32720
-# CHECK-NEXT:     Initial: 0x0
-# CHECK-NEXT:     Value: 0x0
-# CHECK-NEXT:     Type: Function
-# CHECK-NEXT:     Section: Undefined
-# CHECK-NEXT:     Name: foo0
-# CHECK-NEXT:   }
-# CHECK-NEXT: ]
-
-  .text
-  .global __start
-__start:
-  lui     $28, %hi(%neg(%gp_rel(foo0)))
-  addiu   $28, $28, %lo(%neg(%gp_rel(foo0)))
-  lw       $4, %got_page(data)($28)
-  addiu    $4, $4, %got_ofst(data)
-  lw      $25, %call16(foo0)($28)
-
-  .data
-data:
-  .word 0

test/ELF/mips-micro64-reject.test

+# REQUIRES: mips
+#
+# Check that the linker rejects microMIPS64 input files.
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld %t.o -shared -o %t.so 2>&1 | FileCheck %s
+
+# CHECK: linking microMIPS 64-bit files is unsupported: {{.*}}mips-micro64-reject.test
+
+!ELF
+FileHeader:
+  Class:    ELFCLASS64
+  Data:     ELFDATA2MSB
+  Type:     ET_REL
+  Machine:  EM_MIPS
+  Flags:    [ EF_MIPS_MICROMIPS, EF_MIPS_ARCH_64 ]
+
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Content:         00000000
+

test/ELF/mips-micro64-relocs.s

-# REQUIRES: mips
-
-# microMIPS 64-bit is unsupported by LLVM starting from r335057.
-# But such code can be generated by GCC. Mark this test as XFAIL
-# while decide to drop microMIPS 64-bit support from LLD too or
-# use binary inputs for the test.
-# XFAIL: *
-
-# Check handling of some microMIPS relocations in 64-bit mode.
-
-# RUN: llvm-mc -filetype=obj -triple=mips64el-unknown-linux \
-# RUN:         -mattr=micromips %s -o %t1.o
-# RUN: llvm-mc -filetype=obj -triple=mips64el-unknown-linux \
-# RUN:         -mattr=micromips %S/Inputs/mips-dynamic.s -o %t2.o
-# RUN: ld.lld %t1.o %t2.o -o %t.exe
-# RUN: llvm-objdump -d %t.exe | FileCheck %s
-
-  .global  __start
-__start:
-  lui     $7,  %highest(_foo+0x300047FFF7FF8)
-  lui     $7,  %higher (_foo+0x300047FFF7FF8)
-  lui     $gp, %hi(%neg(%gp_rel(__start)))
-  lui     $gp, %lo(%neg(%gp_rel(__start)))
-
-# CHECK:      20000:  a7 41 03 00  lui $7, 3
-# CHECK-NEXT: 20004:  a7 41 05 00  lui $7, 5
-# CHECK-NEXT: 20008:  bc 41 02 00  lui $gp, 2
-# CHECK-NEXT: 2000c:  bc 41 00 80  lui $gp, 32768

test/ELF/mips-non-zero-gp0.s

 # REQUIRES: mips
 
 # Check addend adjustment in case of generating a relocatable object
 # if some input files have non-zero GP0 value.
 
 # We have to use GNU as and ld.bfd 2.28 to generate relocatable object
 # files with non-zero GP0 value using the following command lines:
 #
 # as -mips32 -o test.o \
 #   && ld.bfd -m elf32btsmip -r test.o -o mips-gp0-non-zero.o
-# as -mips64 -mmicromips -o test.o \
-#   && ld.bfd -m elf64btsmip -r test.o -o mips-micro-gp0-non-zero.o
 # as -mips64 -o test.o \
 #   && ld.bfd -m elf64btsmip -r test.o -o mips-n64-gp0-non-zero.o
 
 # Source code for mips-gp0-non-zero.o:
 #   .text
 #   .global  __start
 # __start:
 #   lw      $t0,%call16(__start)($gp)

 # RUN: llvm-readobj -mips-reginfo %t-32.r | FileCheck --check-prefix=GPVAL %s
 # RUN: llvm-objdump -s %t-32.r | FileCheck --check-prefix=ADDEND32 %s
 
 # RUN: ld.lld -r -o %t-64.r %S/Inputs/mips-n64-gp0-non-zero.o
 # RUN: llvm-readobj -mips-options %t-64.r | FileCheck --check-prefix=GPVAL %s
 # RUN: llvm-readobj -r %S/Inputs/mips-n64-gp0-non-zero.o %t-64.r \
 # RUN:   | FileCheck --check-prefix=ADDEND64 %s
 
-# RUN: ld.lld -r -o %t-micro.r %S/Inputs/mips-micro-gp0-non-zero.o
-# RUN: llvm-readobj -mips-options %t-micro.r | FileCheck --check-prefix=GPVAL %s
-# RUN: llvm-readobj -r %S/Inputs/mips-micro-gp0-non-zero.o %t-micro.r \
-# RUN:   | FileCheck --check-prefix=ADDENDMM %s
-
 # GPVAL: GP: 0x0
 
 # ADDEND32:      Contents of section .rodata:
 # ADDEND32-NEXT:  0000 00007ff4 00007ff8
 #                      ^ 4+GP0  ^ 8+GP0
 
 # ADDEND64: File: {{.*}}{{/|\\}}mips-n64-gp0-non-zero.o
 # ADDEND64: .text 0xFFFFFFFFFFFF8011
 # ADDEND64: File: {{.*}}{{/|\\}}mips-non-zero-gp0.s.tmp-64.r
 # ADDEND64: .text 0x0
-
-# ADDENDMM: File: {{.*}}{{/|\\}}mips-micro-gp0-non-zero.o
-# ADDENDMM: .text 0xFFFFFFFFFFFF8012
-# ADDENDMM: File: {{.*}}{{/|\\}}mips-non-zero-gp0.s.tmp-micro.r
-# ADDENDMM: .text 0x1