[mips][ias] Handle N64 compound relocations and R_MIPS_SUB in needsRelocateWithSymbol()

[dsanders]

Summary

This eliminates the default case for N64 that was left out of r269047.

The change to R_MIPS_SUB is needed in this patch to make this testable since
%lo(%neg(%gp_rel(foo))) and %hi(%neg(%gp_rel(foo))) remain the only ways to get
a compound relocation from the assembler.

[• rafael]

LGTM. Thanks

lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp

void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
   // them in reverse order.
   unsigned CopyTo = 0;
   for (const auto &R : reverse(Sorted))
     Relocs[CopyTo++] = R.R;
 }
 
 bool MipsELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
                                                   unsigned Type) const {
-  // This must be a compound relocation from the N64 ABI.
-  // FIXME: Return false iff all sub-relocations return false.
+  // If it's a compound relocation for N64 then we need the relocation if any
+  // sub-relocation needs it.
   if (!isUInt<8>(Type))
-    return true;
+    return needsRelocateWithSymbol(Sym, Type & 0xff) ||
+           needsRelocateWithSymbol(Sym, (Type >> 8) & 0xff) ||
+           needsRelocateWithSymbol(Sym, (Type >> 16) & 0xff);
 
   switch (Type) {
   default:
     errs() << Type << "\n";
     llvm_unreachable("Unexpected relocation");
     return true;
 
   // This relocation doesn't affect the section data.
case ELF::R_MIPS_32:
     if (cast<MCSymbolELF>(Sym).getOther() & ELF::STO_MIPS_MICROMIPS)
       return true;
     // fallthrough
   case ELF::R_MIPS_26:
   case ELF::R_MIPS_64:
   case ELF::R_MIPS_GPREL16:
   case ELF::R_MIPS_GPREL32:
   case ELF::R_MIPS_PC16:
+  case ELF::R_MIPS_SUB:
     return false;
 
   // FIXME: Many of these relocations should probably return false but this
   //        hasn't been confirmed to be safe yet.
   case ELF::R_MIPS_REL32:
   case ELF::R_MIPS_LITERAL:
   case ELF::R_MIPS_CALL16:
   case ELF::R_MIPS_SHIFT5:
   case ELF::R_MIPS_SHIFT6:
   case ELF::R_MIPS_GOT_DISP:
   case ELF::R_MIPS_GOT_PAGE:
   case ELF::R_MIPS_GOT_OFST:
   case ELF::R_MIPS_GOT_HI16:
   case ELF::R_MIPS_GOT_LO16:
-  case ELF::R_MIPS_SUB:
   case ELF::R_MIPS_INSERT_A:
   case ELF::R_MIPS_INSERT_B:
   case ELF::R_MIPS_DELETE:
   case ELF::R_MIPS_HIGHER:
   case ELF::R_MIPS_HIGHEST:
   case ELF::R_MIPS_CALL_HI16:
   case ELF::R_MIPS_CALL_LO16:
   case ELF::R_MIPS_SCN_DISP:
bool MipsELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
   case ELF::R_MIPS16_TLS_LDM:
   case ELF::R_MIPS16_TLS_DTPREL_HI16:
   case ELF::R_MIPS16_TLS_DTPREL_LO16:
   case ELF::R_MIPS16_TLS_GOTTPREL:
   case ELF::R_MIPS16_TLS_TPREL_HI16:
   case ELF::R_MIPS16_TLS_TPREL_LO16:
     llvm_unreachable("Unsupported MIPS16 relocation");
     return true;
-
   }
 }
 
 MCObjectWriter *llvm::createMipsELFObjectWriter(raw_pwrite_stream &OS,
                                                 uint8_t OSABI,
                                                 bool IsLittleEndian,
                                                 bool Is64Bit) {
   MCELFObjectTargetWriter *MOTW =
       new MipsELFObjectWriter(Is64Bit, OSABI, Is64Bit, IsLittleEndian);
   return createELFObjectWriter(MOTW, OS, IsLittleEndian);
 }

test/MC/Mips/cpsetup.s

 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi o32 -filetype=obj -o - %s | \
 # RUN:   llvm-objdump -d -r -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=ALL -check-prefix=O32 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi o32 %s | \
 # RUN:   FileCheck -check-prefix=ALL -check-prefix=ASM %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi n32 -filetype=obj -o - %s | \
-# RUN:   llvm-objdump -d -r -t -arch=mips64 - | \
+# RUN:   llvm-objdump -d -r -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=ALL -check-prefix=NXX -check-prefix=N32 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi n32 %s | \
 # RUN:   FileCheck -check-prefix=ALL -check-prefix=ASM %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown %s -filetype=obj -o - | \
-# RUN:   llvm-objdump -d -r -t -arch=mips64 - | \
+# RUN:   llvm-objdump -d -r -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=ALL -check-prefix=NXX -check-prefix=N64 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown %s | \
 # RUN:   FileCheck -check-prefix=ALL -check-prefix=ASM %s
 
         .text
         .option pic2
 t1:

 
 # O32-NEXT:   nop
 # O32-NEXT:   sub $3, $3, $2
 
 # FIXME: Direct object emission for N32 is still under development.
 # N32 doesn't allow 3 operations to be specified in the same relocation
 # record like N64 does.
 
-# NXX: $tmp0:
 # NXX-NEXT: move     $2, $gp
 # NXX-NEXT: lui      $gp, 0
-# NXX-NEXT: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16  $tmp0
+# NXX-NEXT: {{^ *0+}}40: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16 .text
 # NXX-NEXT: addiu    $gp, $gp, 0
-# NXX-NEXT: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  $tmp0
+# NXX-NEXT: {{^ *0+}}44: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16 .text
 # N32-NEXT: addu     $gp, $gp, $25
 # N64-NEXT: daddu    $gp, $gp, $25
 # NXX-NEXT: nop
 # NXX-NEXT: sub $3, $3, $2
 
 # ASM: $tmp0:
 # ASM-NEXT: .cpsetup $25, $2, $tmp0
 

 # NXX-NEXT: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  __cerror
 # N32-NEXT: addu     $gp, $gp, $25
 # N64-NEXT: daddu    $gp, $gp, $25
 
 # ASM-NEXT: .cpsetup $25, 8, __cerror
 
 # ALL-NEXT: nop
 
-# NXX-LABEL: SYMBOL TABLE:
-
-# For .cpsetup with local labels, we need to check if $tmp0 is in the symbol
-# table:
-# NXX: .text  00000000 $tmp0

test/MC/Mips/relocation-n64.s

+// RUN: llvm-mc -triple mips64-unknown-linux < %s -show-encoding \
+// RUN:     | FileCheck -check-prefix=ENCBE -check-prefix=FIXUP %s
+// RUN: llvm-mc -triple mips64el-unknown-linux < %s -show-encoding \
+// RUN:     | FileCheck -check-prefix=ENCLE -check-prefix=FIXUP %s
+// RUN: llvm-mc -filetype=obj -triple mips64el-unknown-linux < %s \
+// RUN:     | llvm-readobj -r | FileCheck -check-prefix=RELOC %s
+// RUN: llvm-mc -filetype=obj -triple mips64-unknown-linux < %s \
+// RUN:     | llvm-readobj -sections -section-data \
+// RUN:     | FileCheck -check-prefix=DATA %s
+
+// Test that we produce the correct relocation.
+// FIXME: move more relocation only tests here.
+
+// Check prefixes:
+// RELOC - Check the relocation in the object.
+// FIXUP - Check the fixup on the instruction.
+// ENCBE - Check the big-endian encoding on the instruction.
+// ENCLE - Check the little-endian encoding on the instruction.
+// ????? - Placeholder. Relocation is defined but the way of generating it is
+//         unknown.
+// FIXME - Placeholder. Generation method is known but doesn't work.
+
+// DATA-LABEL: Name: .text
+// DATA:       SectionData (
+
+// DATA-NEXT:  0000: 24620000 24620000
+        addiu $2, $3, %lo(%neg(%gp_rel(foo))) // RELOC: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16 foo
+                                              // ENCBE: addiu $2, $3, %lo(%neg(%gp_rel(foo))) # encoding: [0x24,0x62,A,A]
+                                              // ENCLE: addiu $2, $3, %lo(%neg(%gp_rel(foo))) # encoding: [A,A,0x62,0x24]
+                                              // FIXUP: # fixup A - offset: 0, value: %lo(%neg(%gp_rel(foo))), kind: fixup_Mips_GPOFF_LO
+
+        addiu $2, $3, %lo(%neg(%gp_rel(bar))) // RELOC: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16 .data
+                                              // ENCBE: addiu $2, $3, %lo(%neg(%gp_rel(bar))) # encoding: [0x24,0x62,A,A]
+                                              // ENCLE: addiu $2, $3, %lo(%neg(%gp_rel(bar))) # encoding: [A,A,0x62,0x24]
+                                              // FIXUP: # fixup A - offset: 0, value: %lo(%neg(%gp_rel(bar))), kind: fixup_Mips_GPOFF_LO
+
+        .data
+        .word 0
+bar:
+        .word 1
+// DATA-LABEL: Section {