Revert "[lld][LoongArch] Relax call36/tail36: R_LARCH_CALL36 (#123576)"

This reverts commit 6fbe491.
Broke check-lld, see the many bot comments on
llvm/llvm-project#123576

Author: nico

lld/ELF/Arch/LoongArch.cpp

@@ -58,8 +58,6 @@ enum Op {
   LD_W = 0x28800000,
   LD_D = 0x28c00000,
   JIRL = 0x4c000000,
-  B = 0x50000000,
-  BL = 0x54000000,
 };
 
 enum Reg {
@@ -832,37 +830,6 @@ static void relaxPCHi20Lo12(Ctx &ctx, const InputSection &sec, size_t i,
   remove = 4;
 }
 
-// Relax code sequence.
-// From:
-//   pcaddu18i $ra, %call36(foo)
-//   jirl $ra, $ra, 0
-// To:
-//   b/bl foo
-static void relaxCall36(Ctx &ctx, const InputSection &sec, size_t i,
-                        uint64_t loc, Relocation &r, uint32_t &remove) {
-  const uint64_t dest =
-      (r.expr == R_PLT_PC ? r.sym->getPltVA(ctx) : r.sym->getVA(ctx)) +
-      r.addend;
-
-  const int64_t displace = dest - loc;
-  // Check if the displace aligns 4 bytes or exceeds the range of b[l].
-  if ((displace & 0x3) != 0 || !isInt<28>(displace))
-    return;
-
-  const uint32_t nextInsn = read32le(sec.content().data() + r.offset + 4);
-  if (getD5(nextInsn) == R_RA) {
-    // convert jirl to bl
-    sec.relaxAux->relocTypes[i] = R_LARCH_B26;
-    sec.relaxAux->writes.push_back(insn(BL, 0, 0, 0));
-    remove = 4;
-  } else if (getD5(nextInsn) == R_ZERO) {
-    // convert jirl to b
-    sec.relaxAux->relocTypes[i] = R_LARCH_B26;
-    sec.relaxAux->writes.push_back(insn(B, 0, 0, 0));
-    remove = 4;
-  }
-}
-
 static bool relax(Ctx &ctx, InputSection &sec) {
   const uint64_t secAddr = sec.getVA();
   const MutableArrayRef<Relocation> relocs = sec.relocs();
@@ -907,10 +874,6 @@ static bool relax(Ctx &ctx, InputSection &sec) {
       if (isPairRelaxable(relocs, i))
         relaxPCHi20Lo12(ctx, sec, i, loc, r, relocs[i + 2], remove);
       break;
-    case R_LARCH_CALL36:
-      if (relaxable(relocs, i))
-        relaxCall36(ctx, sec, i, loc, r, remove);
-      break;
     }
 
     // For all anchors whose offsets are <= r.offset, they are preceded by
@@ -1014,10 +977,6 @@ void LoongArch::finalizeRelax(int passes) const {
             // RelExpr is needed for relocating.
             r.expr = r.sym->hasFlag(NEEDS_PLT) ? R_PLT_PC : R_PC;
             break;
-          case R_LARCH_B26:
-            skip = 4;
-            write32le(p, aux.writes[writesIdx++]);
-            break;
           default:
             llvm_unreachable("unsupported type");
           }

lld/test/ELF/loongarch-relax-call36-2.s

@@ -2,11 +2,11 @@
 ## Test that we can handle --emit-relocs while relaxing.
 
 # RUN: llvm-mc --filetype=obj --triple=loongarch32 --mattr=+relax %s -o %t.32.o
-# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax --defsym ELF64=1 %s -o %t.64.o
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.64.o
 # RUN: ld.lld -Ttext=0x10000 -section-start=.got=0x20000 --emit-relocs %t.32.o -o %t.32
 # RUN: ld.lld -Ttext=0x10000 -section-start=.got=0x20000 --emit-relocs %t.64.o -o %t.64
-# RUN: llvm-objdump -dr %t.32 | FileCheck %s --check-prefixes=RELAX,RELAX32
-# RUN: llvm-objdump -dr %t.64 | FileCheck %s --check-prefixes=RELAX,RELAX64
+# RUN: llvm-objdump -dr %t.32 | FileCheck %s --check-prefix=RELAX
+# RUN: llvm-objdump -dr %t.64 | FileCheck %s --check-prefix=RELAX
 
 ## -r should keep original relocations.
 # RUN: ld.lld -r %t.64.o -o %t.64.r
@@ -27,19 +27,10 @@
 # RELAX-NEXT:     R_LARCH_RELAX *ABS*
 # RELAX-NEXT:     R_LARCH_PCREL20_S2 _start
 # RELAX-NEXT:     R_LARCH_RELAX *ABS*
-# RELAX32-NEXT:  nop
-# RELAX32-NEXT:    R_LARCH_ALIGN *ABS*+0xc
-# RELAX32-NEXT:  nop
-# RELAX32-NEXT:  ret
-
-# RELAX64-NEXT:  bl  -8
-# RELAX64-NEXT:    R_LARCH_B26 _start
-# RELAX64-NEXT:    R_LARCH_RELAX *ABS*
-# RELAX64-NEXT:  b   -12
-# RELAX64-NEXT:    R_LARCH_B26 _start
-# RELAX64-NEXT:    R_LARCH_RELAX *ABS*
-# RELAX64-NEXT:  ret
-# RELAX64-NEXT:    R_LARCH_ALIGN *ABS*+0xc
+# RELAX-NEXT:   nop
+# RELAX-NEXT:     R_LARCH_ALIGN *ABS*+0xc
+# RELAX-NEXT:   nop
+# RELAX-NEXT:   ret
 
 # NORELAX:      <_start>:
 # NORELAX-NEXT:   pcalau12i $a0, 0
@@ -54,14 +45,6 @@
 # NORELAX-NEXT:   ld.d      $a0, $a0, 0
 # NORELAX-NEXT:     R_LARCH_GOT_PC_LO12 _start
 # NORELAX-NEXT:     R_LARCH_RELAX *ABS*
-# NORELAX-NEXT:   pcaddu18i $ra, 0
-# NORELAX-NEXT:     R_LARCH_CALL36 _start
-# NORELAX-NEXT:     R_LARCH_RELAX *ABS*
-# NORELAX-NEXT:   jirl   $ra, $ra, -16
-# NORELAX-NEXT:   pcaddu18i $a0, 0
-# NORELAX-NEXT:     R_LARCH_CALL36 _start
-# NORELAX-NEXT:     R_LARCH_RELAX *ABS*
-# NORELAX-NEXT:   jirl $zero, $a0, -24
 # NORELAX-NEXT:   ret
 # NORELAX-NEXT:     R_LARCH_ALIGN *ABS*+0xc
 
@@ -78,14 +61,6 @@
 # CHECKR-NEXT:   ld.d      $a0, $a0, 0
 # CHECKR-NEXT:     R_LARCH_GOT_PC_LO12 _start
 # CHECKR-NEXT:     R_LARCH_RELAX *ABS*
-# CHECKR-NEXT:   pcaddu18i $ra, 0
-# CHECKR-NEXT:     R_LARCH_CALL36 _start
-# CHECKR-NEXT:     R_LARCH_RELAX *ABS*
-# CHECKR-NEXT:   jirl   $ra, $ra, 0
-# CHECKR-NEXT:   pcaddu18i $a0, 0
-# CHECKR-NEXT:     R_LARCH_CALL36 _start
-# CHECKR-NEXT:     R_LARCH_RELAX *ABS*
-# CHECKR-NEXT:   jr     $a0
 # CHECKR-NEXT:   nop
 # CHECKR-NEXT:     R_LARCH_ALIGN *ABS*+0xc
 # CHECKR-NEXT:   nop
@@ -96,10 +71,5 @@
 _start:
   la.pcrel $a0, _start
   la.got   $a0, _start
-
-.ifdef ELF64
-  call36 _start
-  tail36 $a0, _start
-.endif
   .p2align 4
   ret