[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 ↗

(On Diff #154144)

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 ↗

(On Diff #154144)

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 ↗

(On Diff #154144)

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

lld/trunk/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)

lld/trunk/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=" +

lld/trunk/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

lld/trunk/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
+

lld/trunk/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

lld/trunk/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