[X86][MC,LLD][NFC] Rename R_X86_64_REX2_GOTPCRELX (llvm#116737)

Rename R_X86_64_REX2_GOTPCRELX to R_X86_64_CODE_4_GOTPCRELX, to align
with GCC/binutils and ABI.

GCC/binutils:
bminor/binutils-gdb@3d5a60d
and
bminor/binutils-gdb@4a54cb0
ABI:
https://gitlab.com/x86-psABIs/x86-64-ABI/-/commit/357de358ba68eb779822dfcbb45f7ee2d9d09193

Author: fzou1

clang/test/Driver/relax.s

@@ -8,7 +8,7 @@
 // RUN: llvm-readobj -r %t | FileCheck --check-prefix=REL %s
 
 // REL: R_X86_64_REX_GOTPCRELX foo
-// REL: R_X86_64_REX2_GOTPCRELX foo
+// REL: R_X86_64_CODE_4_GOTPCRELX foo
 
         movq	foo@GOTPCREL(%rip), %rax
         movq	foo@GOTPCREL(%rip), %r16

lld/ELF/Arch/X86_64.cpp

@@ -394,7 +394,7 @@ RelExpr X86_64::getRelExpr(RelType type, const Symbol &s,
   case R_X86_64_GOTPCREL:
   case R_X86_64_GOTPCRELX:
   case R_X86_64_REX_GOTPCRELX:
-  case R_X86_64_REX2_GOTPCRELX:
+  case R_X86_64_CODE_4_GOTPCRELX:
   case R_X86_64_GOTTPOFF:
     return R_GOT_PC;
   case R_X86_64_GOTOFF64:
@@ -738,7 +738,7 @@ int64_t X86_64::getImplicitAddend(const uint8_t *buf, RelType type) const {
   case R_X86_64_GOTPCREL:
   case R_X86_64_GOTPCRELX:
   case R_X86_64_REX_GOTPCRELX:
-  case R_X86_64_REX2_GOTPCRELX:
+  case R_X86_64_CODE_4_GOTPCRELX:
   case R_X86_64_PC32:
   case R_X86_64_GOTTPOFF:
   case R_X86_64_PLT32:
@@ -821,7 +821,7 @@ void X86_64::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
     break;
   case R_X86_64_GOTPCRELX:
   case R_X86_64_REX_GOTPCRELX:
-  case R_X86_64_REX2_GOTPCRELX:
+  case R_X86_64_CODE_4_GOTPCRELX:
     if (rel.expr != R_GOT_PC) {
       relaxGot(loc, rel, val);
     } else {
@@ -873,13 +873,13 @@ void X86_64::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
 
 RelExpr X86_64::adjustGotPcExpr(RelType type, int64_t addend,
                                 const uint8_t *loc) const {
-  // Only R_X86_64_[REX_]|[REX2_]GOTPCRELX can be relaxed. GNU as may emit
+  // Only R_X86_64_[REX_]|[CODE_4_]GOTPCRELX can be relaxed. GNU as may emit
   // GOTPCRELX with addend != -4. Such an instruction does not load the full GOT
   // entry, so we cannot relax the relocation. E.g. movl x@GOTPCREL+4(%rip),
   // %rax (addend=0) loads the high 32 bits of the GOT entry.
   if (!ctx.arg.relax || addend != -4 ||
       (type != R_X86_64_GOTPCRELX && type != R_X86_64_REX_GOTPCRELX &&
-       type != R_X86_64_REX2_GOTPCRELX))
+       type != R_X86_64_CODE_4_GOTPCRELX))
     return R_GOT_PC;
   const uint8_t op = loc[-2];
   const uint8_t modRm = loc[-1];
@@ -1002,7 +1002,8 @@ static void relaxGot(uint8_t *loc, const Relocation &rel, uint64_t val) {
     // We are relaxing a rip relative to an absolute, so compensate
     // for the old -4 addend.
     assert(!rel.sym->file || !rel.sym->file->ctx.arg.isPic);
-    relaxGotNoPic(loc, val + 4, op, modRm, rel.type == R_X86_64_REX2_GOTPCRELX);
+    relaxGotNoPic(loc, val + 4, op, modRm,
+                  rel.type == R_X86_64_CODE_4_GOTPCRELX);
     return;
   }
 

lld/test/ELF/x86-64-gotpc-no-relax-err.s

@@ -13,7 +13,7 @@
 # CHECK-NEXT: error: {{.*}}:(.text+0x9): relocation R_X86_64_REX_GOTPCRELX out of range: 2147483659 is not in [-2147483648, 2147483647]; references '__stop_data'
 # CHECK-NEXT: >>> defined in <internal>
 # CHECK-EMPTY:
-# CHECK-NEXT: error: {{.*}}:(.text+0x11): relocation R_X86_64_REX2_GOTPCRELX out of range: 2147483651 is not in [-2147483648, 2147483647]; references '__stop_data'
+# CHECK-NEXT: error: {{.*}}:(.text+0x11): relocation R_X86_64_CODE_4_GOTPCRELX out of range: 2147483651 is not in [-2147483648, 2147483647]; references '__stop_data'
 # CHECK-NEXT: >>> defined in <internal>
 
 #--- a.s

lld/test/ELF/x86-64-gotpc-relax-nopic.s

@@ -134,7 +134,7 @@ _start:
   xorq    bar@GOTPCREL(%rip), %r8
   testq   %r15, bar@GOTPCREL(%rip)
 
-## R_X86_64_REX2_GOTPCRELX
+## R_X86_64_CODE_4_GOTPCRELX
   adcq    bar@GOTPCREL(%rip), %r16
   addq    bar@GOTPCREL(%rip), %r17
   andq    bar@GOTPCREL(%rip), %r18

lld/test/ELF/x86-64-gotpc-relax.s

@@ -1,5 +1,5 @@
 # REQUIRES: x86
-## Test R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX/R_X86_64_REX2_GOTPCRELX GOT optimization.
+## Test R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX/R_X86_64_CODE_4_GOTPCRELX GOT optimization.
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 # RUN: ld.lld %t.o -o %t1 --no-apply-dynamic-relocs

llvm/include/llvm/BinaryFormat/ELFRelocs/x86_64.def

@@ -43,4 +43,4 @@ ELF_RELOC(R_X86_64_TLSDESC,     36)
 ELF_RELOC(R_X86_64_IRELATIVE,   37)
 ELF_RELOC(R_X86_64_GOTPCRELX,   41)
 ELF_RELOC(R_X86_64_REX_GOTPCRELX,    42)
-ELF_RELOC(R_X86_64_REX2_GOTPCRELX,    43)
+ELF_RELOC(R_X86_64_CODE_4_GOTPCRELX,    43)

llvm/lib/MC/MCTargetOptionsCommandFlags.cpp

@@ -145,7 +145,7 @@ llvm::mc::RegisterMCTargetOptionsFlags::RegisterMCTargetOptionsFlags() {
 
   static cl::opt<bool> X86RelaxRelocations(
       "x86-relax-relocations",
-      cl::desc("Emit GOTPCRELX/REX_GOTPCRELX/REX2_GOTPCRELX instead of "
+      cl::desc("Emit GOTPCRELX/REX_GOTPCRELX/CODE_4_GOTPCRELX instead of "
                "GOTPCREL on x86-64 ELF"),
       cl::init(true));
   MCBINDOPT(X86RelaxRelocations);

llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp

@@ -207,7 +207,7 @@ static unsigned getRelocType64(MCContext &Ctx, SMLoc Loc,
   case MCSymbolRefExpr::VK_GOTPCREL:
     checkIs32(Ctx, Loc, Type);
     // Older versions of ld.bfd/ld.gold/lld
-    // do not support GOTPCRELX/REX_GOTPCRELX/REX2_GOTPCRELX,
+    // do not support GOTPCRELX/REX_GOTPCRELX/CODE_4_GOTPCRELX,
     // and we want to keep back-compatibility.
     if (!Ctx.getTargetOptions()->X86RelaxRelocations)
       return ELF::R_X86_64_GOTPCREL;
@@ -221,7 +221,7 @@ static unsigned getRelocType64(MCContext &Ctx, SMLoc Loc,
       return ELF::R_X86_64_REX_GOTPCRELX;
     case X86::reloc_riprel_4byte_relax_rex2:
     case X86::reloc_riprel_4byte_movq_load_rex2:
-      return ELF::R_X86_64_REX2_GOTPCRELX;
+      return ELF::R_X86_64_CODE_4_GOTPCRELX;
     }
     llvm_unreachable("unexpected relocation type!");
   case MCSymbolRefExpr::VK_GOTPCREL_NORELAX:

llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp

@@ -641,7 +641,7 @@ void X86MCCodeEmitter::emitMemModRMByte(
       case X86::MOV64rm:
         // movq loads is a subset of reloc_riprel_4byte_relax_rex/rex2. It is a
         // special case because COFF and Mach-O don't support ELF's more
-        // flexible R_X86_64_REX_GOTPCRELX/R_X86_64_REX2_GOTPCRELX relaxation.
+        // flexible R_X86_64_REX_GOTPCRELX/R_X86_64_CODE_4_GOTPCRELX relaxation.
         return Kind == REX2 ? X86::reloc_riprel_4byte_movq_load_rex2
                             : X86::reloc_riprel_4byte_movq_load;
       case X86::ADC32rm:

llvm/test/MC/ELF/relocation-alias.s

@@ -17,7 +17,7 @@ movabsq $memcpy+2, %rax
 # CHECK:      movq (%rip), %rax
 # CHECK-NEXT:   R_X86_64_REX_GOTPCRELX  abs-0x4
 # CHECK:      movq (%rip), %r16
-# CHECK-NEXT:   R_X86_64_REX2_GOTPCRELX abs-0x4
+# CHECK-NEXT:   R_X86_64_CODE_4_GOTPCRELX abs-0x4
 movq abs@GOTPCREL(%rip), %rax
 movq abs@GOTPCREL(%rip), %r16
 abs = 42