[LoongArch] Add relax relocations for tls_le code sequence (#121329)

This commit add relax relocations for `tls_le` code sequence.
Handwritten assembly and generating source code by clang are both
affected.

Scheduled `tls_le` code sequence can be relaxed normally and we can add
relax relocs when code emitting according to their relocs. Other
relaxable macros' code sequence cannot simply add relax relocs according
to their relocs, such as `PCALA_{HI20/LO12}`, we do not want to add
relax relocs when code model is large. This will be implemented in later
commit.

Author: zhaoqi5

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCCodeEmitter.cpp

@@ -282,9 +282,11 @@ LoongArchMCCodeEmitter::getExprOpValue(const MCInst &MI, const MCOperand &MO,
       break;
     case LoongArchMCExpr::VK_LoongArch_TLS_LE_HI20_R:
       FixupKind = LoongArch::fixup_loongarch_tls_le_hi20_r;
+      RelaxCandidate = true;
       break;
     case LoongArchMCExpr::VK_LoongArch_TLS_LE_LO12_R:
       FixupKind = LoongArch::fixup_loongarch_tls_le_lo12_r;
+      RelaxCandidate = true;
       break;
     case LoongArchMCExpr::VK_LoongArch_PCREL20_S2:
       FixupKind = LoongArch::fixup_loongarch_pcrel20_s2;
@@ -387,11 +389,17 @@ void LoongArchMCCodeEmitter::expandAddTPRel(const MCInst &MI,
          "Expected %le_add_r relocation on TP-relative symbol");
 
   // Emit the correct %le_add_r relocation for the symbol.
-  // TODO: Emit R_LARCH_RELAX for %le_add_r where the relax feature is enabled.
   Fixups.push_back(MCFixup::create(
       0, Expr, MCFixupKind(LoongArch::fixup_loongarch_tls_le_add_r),
       MI.getLoc()));
 
+  // Emit R_LARCH_RELAX for %le_add_r when the relax feature is enabled.
+  if (STI.hasFeature(LoongArch::FeatureRelax)) {
+    const MCConstantExpr *Dummy = MCConstantExpr::create(0, Ctx);
+    Fixups.push_back(MCFixup::create(
+        0, Dummy, MCFixupKind(LoongArch::fixup_loongarch_relax), MI.getLoc()));
+  }
+
   // Emit a normal ADD instruction with the given operands.
   unsigned ADD = MI.getOpcode() == LoongArch::PseudoAddTPRel_D
                      ? LoongArch::ADD_D

llvm/test/MC/LoongArch/Relocations/relax-tls-le.s

@@ -0,0 +1,70 @@
+# RUN: llvm-mc --filetype=obj --triple=loongarch32 --mattr=+relax < %s \
+# RUN:     | llvm-readobj -r - | FileCheck --check-prefix=LA32-RELAX-RELOC %s
+# RUN: llvm-mc --filetype=obj --triple=loongarch32 --mattr=-relax < %s \
+# RUN:     | llvm-readobj -r - | FileCheck --check-prefix=LA32-NORELAX-RELOC %s
+# RUN: llvm-mc --triple=loongarch32 --mattr=+relax < %s --show-encoding \
+# RUN:     | FileCheck --check-prefix=LA32-RELAX-FIXUP %s
+
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax --defsym=LA64=1 < %s \
+# RUN:     | llvm-readobj -r - | FileCheck --check-prefix=LA64-RELAX-RELOC %s
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=-relax --defsym=LA64=1 < %s \
+# RUN:     | llvm-readobj -r - | FileCheck --check-prefix=LA64-NORELAX-RELOC %s
+# RUN: llvm-mc --triple=loongarch64 --mattr=+relax --defsym=LA64=1 < %s --show-encoding \
+# RUN:     | FileCheck --check-prefix=LA64-RELAX-FIXUP %s
+
+.long foo
+
+.ifndef LA64
+
+lu12i.w $a0, %le_hi20_r(foo)
+# LA32-NORELAX-RELOC: R_LARCH_TLS_LE_HI20_R foo 0x0
+# LA32-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA32-RELAX-RELOC: R_LARCH_TLS_LE_HI20_R foo 0x0
+# LA32-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA32-RELAX-FIXUP: fixup A - offset: 0, value: %le_hi20_r(foo), kind: FK_NONE
+# LA32-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+add.w $a0, $a0, $tp, %le_add_r(foo)
+# LA32-NORELAX-RELOC: R_LARCH_TLS_LE_ADD_R foo 0x0
+# LA32-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA32-RELAX-RELOC: R_LARCH_TLS_LE_ADD_R foo 0x0
+# LA32-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA32-RELAX-FIXUP: fixup A - offset: 0, value: %le_add_r(foo), kind: FK_NONE
+# LA32-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+addi.w $a0, $a0, %le_lo12_r(foo)
+# LA32-NORELAX-RELOC: R_LARCH_TLS_LE_LO12_R foo 0x0
+# LA32-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA32-RELAX-RELOC: R_LARCH_TLS_LE_LO12_R foo 0x0
+# LA32-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA32-RELAX-FIXUP: fixup A - offset: 0, value: %le_lo12_r(foo), kind: FK_NONE
+# LA32-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+.else
+
+lu12i.w $a0, %le_hi20_r(foo)
+# LA64-NORELAX-RELOC: R_LARCH_TLS_LE_HI20_R foo 0x0
+# LA64-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA64-RELAX-RELOC: R_LARCH_TLS_LE_HI20_R foo 0x0
+# LA64-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA64-RELAX-FIXUP: fixup A - offset: 0, value: %le_hi20_r(foo), kind: FK_NONE
+# LA64-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+add.d $a0, $a0, $tp, %le_add_r(foo)
+# LA64-NORELAX-RELOC: R_LARCH_TLS_LE_ADD_R foo 0x0
+# LA64-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA64-RELAX-RELOC: R_LARCH_TLS_LE_ADD_R foo 0x0
+# LA64-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA64-RELAX-FIXUP: fixup A - offset: 0, value: %le_add_r(foo), kind: FK_NONE
+# LA64-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+addi.d $a0, $a0, %le_lo12_r(foo)
+# LA64-NORELAX-RELOC: R_LARCH_TLS_LE_LO12_R foo 0x0
+# LA64-NORELAX-RELOC-NOT: R_LARCH_RELAX - 0x0
+# LA64-RELAX-RELOC: R_LARCH_TLS_LE_LO12_R foo 0x0
+# LA64-RELAX-RELOC: R_LARCH_RELAX - 0x0
+# LA64-RELAX-FIXUP: fixup A - offset: 0, value: %le_lo12_r(foo), kind: FK_NONE
+# LA64-RELAX-FIXUP: fixup B - offset: 0, value: 0, kind: FK_NONE
+
+.endif
+