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[lld][LoongArch] Relax TLSDESC code sequence #123677

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Mar 31, 2025
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[lld][LoongArch] Relax TLSDESC code sequence #123677

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9d29d9b
Relax TLSDESC code sequence.
ylzsx Dec 31, 2024
49f1b5c
fix typo error
ylzsx Mar 20, 2025
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19 changes: 17 additions & 2 deletions lld/ELF/Arch/LoongArch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -766,9 +766,12 @@ static bool isPairRelaxable(ArrayRef<Relocation> relocs, size_t i) {
// Relax code sequence.
// From:
// pcalau12i $a0, %pc_hi20(sym) | %ld_pc_hi20(sym) | %gd_pc_hi20(sym)
// | %desc_pc_hi20(sym)
// addi.w/d $a0, $a0, %pc_lo12(sym) | %got_pc_lo12(sym) | %got_pc_lo12(sym)
// | %desc_pc_lo12(sym)
// To:
// pcaddi $a0, %pc_lo12(sym) | %got_pc_lo12(sym) | %got_pc_lo12(sym)
// pcaddi $a0, %pc_lo12(sym) | %got_pc_lo12(sym) | %got_pc_lo12(sym)
// | %desc_pcrel_20(sym)
//
// From:
// pcalau12i $a0, %got_pc_hi20(sym_got)
Expand All @@ -786,7 +789,9 @@ static void relaxPCHi20Lo12(Ctx &ctx, const InputSection &sec, size_t i,
(rHi20.type == R_LARCH_TLS_GD_PC_HI20 &&
rLo12.type == R_LARCH_GOT_PC_LO12) ||
(rHi20.type == R_LARCH_TLS_LD_PC_HI20 &&
rLo12.type == R_LARCH_GOT_PC_LO12)))
rLo12.type == R_LARCH_GOT_PC_LO12) ||
(rHi20.type == R_LARCH_TLS_DESC_PC_HI20 &&
rLo12.type == R_LARCH_TLS_DESC_PC_LO12)))
return;

// GOT references to absolute symbols can't be relaxed to use pcaddi in
Expand All @@ -808,6 +813,8 @@ static void relaxPCHi20Lo12(Ctx &ctx, const InputSection &sec, size_t i,
dest = rHi20.sym->getVA(ctx);
else if (rHi20.expr == RE_LOONGARCH_TLSGD_PAGE_PC)
dest = ctx.in.got->getGlobalDynAddr(*rHi20.sym);
else if (rHi20.expr == RE_LOONGARCH_TLSDESC_PAGE_PC)
dest = ctx.in.got->getTlsDescAddr(*rHi20.sym);
else {
Err(ctx) << getErrorLoc(ctx, (const uint8_t *)loc) << "unknown expr ("
<< rHi20.expr << ") against symbol " << rHi20.sym
Expand Down Expand Up @@ -841,6 +848,8 @@ static void relaxPCHi20Lo12(Ctx &ctx, const InputSection &sec, size_t i,
sec.relaxAux->relocTypes[i + 2] = R_LARCH_TLS_GD_PCREL20_S2;
else if (rHi20.type == R_LARCH_TLS_LD_PC_HI20)
sec.relaxAux->relocTypes[i + 2] = R_LARCH_TLS_LD_PCREL20_S2;
else if (rHi20.type == R_LARCH_TLS_DESC_PC_HI20)
sec.relaxAux->relocTypes[i + 2] = R_LARCH_TLS_DESC_PCREL20_S2;
else
sec.relaxAux->relocTypes[i + 2] = R_LARCH_PCREL20_S2;
sec.relaxAux->writes.push_back(insn(PCADDI, getD5(nextInsn), 0, 0));
Expand Down Expand Up @@ -947,6 +956,7 @@ static bool relax(Ctx &ctx, InputSection &sec) {
case R_LARCH_GOT_PC_HI20:
case R_LARCH_TLS_GD_PC_HI20:
case R_LARCH_TLS_LD_PC_HI20:
case R_LARCH_TLS_DESC_PC_HI20:
// The overflow check for i+2 will be carried out in isPairRelaxable.
if (isPairRelaxable(relocs, i))
relaxPCHi20Lo12(ctx, sec, i, loc, r, relocs[i + 2], remove);
Expand Down Expand Up @@ -1081,6 +1091,11 @@ void LoongArch::finalizeRelax(int passes) const {
write32le(p, aux.writes[writesIdx++]);
r.expr = R_TLSGD_PC;
break;
case R_LARCH_TLS_DESC_PCREL20_S2:
skip = 4;
write32le(p, aux.writes[writesIdx++]);
r.expr = R_TLSDESC_PC;
break;
default:
llvm_unreachable("unsupported type");
}
Expand Down
280 changes: 280 additions & 0 deletions lld/test/ELF/loongarch-relax-tlsdesc.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,280 @@
# REQUIRES: loongarch
# RUN: rm -rf %t && split-file %s %t && cd %t
# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax a.s -o a.64.o
# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax c.s -o c.64.o
# RUN: ld.lld --relax -shared -soname=c.64.so c.64.o -o c.64.so

## Test the TLSDESC relaxation.
# RUN: ld.lld --relax -shared -z now a.64.o c.64.o -o a.64.so
# RUN: llvm-readobj -r -x .got a.64.so | FileCheck --check-prefix=GD64-RELA %s
# RUN: llvm-objdump --no-show-raw-insn -dr -h a.64.so | FileCheck %s --check-prefix=GD64

## FIXME: The transition from TLSDESC to IE/LE has not yet been implemented.
## Keep the dynamic relocations and hand them over to dynamic linker.

# RUN: ld.lld --relax -e 0 -z now a.64.o c.64.o -o a.64.le
# RUN: llvm-readobj -r -x .got a.64.le | FileCheck --check-prefix=LE64-RELA %s
# RUN: llvm-objdump --no-show-raw-insn -d -h a.64.le | FileCheck %s --check-prefix=LE64

# RUN: ld.lld --no-relax -e 0 -z now a.64.o c.64.o -o a.64.le.norelax
# RUN: llvm-objdump --no-show-raw-insn -d -h a.64.le.norelax | FileCheck %s --check-prefix=LE64-NORELAX

# RUN: ld.lld --relax -e 0 -z now a.64.o c.64.so -o a.64.ie
# RUN: llvm-readobj -r -x .got a.64.ie | FileCheck --check-prefix=IE64-RELA %s
# RUN: llvm-objdump --no-show-raw-insn -d -h a.64.ie | FileCheck %s --check-prefix=IE64

# RUN: ld.lld --no-relax -e 0 -z now a.64.o c.64.so -o a.64.ie.norelax
# RUN: llvm-objdump --no-show-raw-insn -d -h a.64.ie.norelax | FileCheck %s --check-prefix=IE64-NORELAX

# GD64-RELA: .rela.dyn {
# GD64-RELA-NEXT: 0x20460 R_LARCH_TLS_DESC64 - 0x7FF
# GD64-RELA-NEXT: 0x20430 R_LARCH_TLS_DESC64 a 0x0
# GD64-RELA-NEXT: 0x20440 R_LARCH_TLS_DESC64 c 0x0
# GD64-RELA-NEXT: 0x20450 R_LARCH_TLS_DESC64 d 0x0
# GD64-RELA-NEXT: }
# GD64-RELA: Hex dump of section '.got':
# GD64-RELA-NEXT: 0x00020430 00000000 00000000 00000000 00000000 .
# GD64-RELA-NEXT: 0x00020440 00000000 00000000 00000000 00000000 .
# GD64-RELA-NEXT: 0x00020450 00000000 00000000 00000000 00000000 .
# GD64-RELA-NEXT: 0x00020460 00000000 00000000 00000000 00000000 .

# GD64: .got 00000040 0000000000020430

## &.got[a]-. = 0x20430 - 0x10318 = 16454<<2
# GD64: 10318: pcaddi $a0, 16454
# GD64-NEXT: ld.d $ra, $a0, 0
# GD64-NEXT: jirl $ra, $ra, 0
# GD64-NEXT: add.d $a1, $a0, $tp

## &.got[b]-. = 0x20430+48 - 0x10328: 0x10 pages, page offset 0x460
## R_LARCH_RELAX does not appear in pairs. No relaxation.
# GD64: 10328: pcalau12i $a0, 16
# GD64-NEXT: addi.d $a0, $a0, 1120
# GD64-NEXT: ld.d $ra, $a0, 0
# GD64-NEXT: jirl $ra, $ra, 0
# GD64-NEXT: add.d $a2, $a0, $tp

## &.got[c]-. = 0x20430+16 - 0x1033c: 0x10 pages, page offset 0x440
## Without R_LARCH_RELAX relocation. No relaxation.
# GD64: 1033c: pcalau12i $a0, 16
# GD64-NEXT: addi.d $t0, $zero, 0
# GD64-NEXT: addi.d $a0, $a0, 1088
# GD64-NEXT: addi.d $t0, $t0, 1
# GD64-NEXT: ld.d $ra, $a0, 0
# GD64-NEXT: addi.d $t0, $t0, 1
# GD64-NEXT: jirl $ra, $ra, 0
# GD64-NEXT: add.d $a3, $a0, $tp

## &.got[d]-. = 0x20430+32 - 0x1035c = 16445<<2
# GD64: 1035c: pcaddi $a0, 16445
# GD64-NEXT: ld.d $ra, $a0, 0
# GD64-NEXT: jirl $ra, $ra, 0
# GD64-NEXT: add.d $a4, $a0, $tp

# LE64-RELA: .rela.dyn {
# LE64-RELA-NEXT: 0x30280 R_LARCH_TLS_DESC64 - 0x8
# LE64-RELA-NEXT: 0x30290 R_LARCH_TLS_DESC64 - 0x800
# LE64-RELA-NEXT: 0x302A0 R_LARCH_TLS_DESC64 - 0x1000
# LE64-RELA-NEXT: 0x302B0 R_LARCH_TLS_DESC64 - 0x7FF
# LE64-RELA-NEXT: }
# LE64-RELA: Hex dump of section '.got':
# LE64-RELA-NEXT: 0x00030280 00000000 00000000 00000000 00000000 .
# LE64-RELA-NEXT: 0x00030290 00000000 00000000 00000000 00000000 .
# LE64-RELA-NEXT: 0x000302a0 00000000 00000000 00000000 00000000 .
# LE64-RELA-NEXT: 0x000302b0 00000000 00000000 00000000 00000000 .

# LE64: .got 00000040 0000000000030280

## &.got[a]-. = 0x30280 - 0x20228 = 16406<<2
# LE64: 20228: pcaddi $a0, 16406
# LE64-NEXT: ld.d $ra, $a0, 0
# LE64-NEXT: jirl $ra, $ra, 0
# LE64-NEXT: add.d $a1, $a0, $tp

## &.got[b]-. = 0x30280+48 - 0x20238: 0x10 pages, page offset 0x2b0
## R_LARCH_RELAX does not appear in pairs. No relaxation.
# LE64: 20238: pcalau12i $a0, 16
# LE64-NEXT: addi.d $a0, $a0, 688
# LE64-NEXT: ld.d $ra, $a0, 0
# LE64-NEXT: jirl $ra, $ra, 0
# LE64-NEXT: add.d $a2, $a0, $tp

## &.got[c]-. = 0x30280+16 - 0x2024c: 0x10 pages, page offset 0x290
## Without R_LARCH_RELAX relocation. No relaxation.
# LE64: 2024c: pcalau12i $a0, 16
# LE64-NEXT: addi.d $t0, $zero, 0
# LE64-NEXT: addi.d $a0, $a0, 656
# LE64-NEXT: addi.d $t0, $t0, 1
# LE64-NEXT: ld.d $ra, $a0, 0
# LE64-NEXT: addi.d $t0, $t0, 1
# LE64-NEXT: jirl $ra, $ra, 0
# LE64-NEXT: add.d $a3, $a0, $tp

## &.got[d]-. = 0x30280+32 - 0x2026c = 16397<<2
# LE64: 2026c: pcaddi $a0, 16397
# LE64-NEXT: ld.d $ra, $a0, 0
# LE64-NEXT: jirl $ra, $ra, 0
# LE64-NEXT: add.d $a4, $a0, $tp

# LE64-NORELAX: .got 00000040 0000000000030288

## &.got[a]-. = 0x30288 - 0x20228 = 0x10 pages, page offset 0x288
# LE64-NORELAX: 20228: pcalau12i $a0, 16
# LE64-NORELAX-NEXT: addi.d $a0, $a0, 648
# LE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# LE64-NORELAX-NEXT: jirl $ra, $ra, 0
# LE64-NORELAX-NEXT: add.d $a1, $a0, $tp

## &.got[b]-. = 0x30288+48 - 0x2023c: 0x10 pages, page offset 0x2b8
## R_LARCH_RELAX does not appear in pairs. No relaxation.
# LE64-NORELAX: 2023c: pcalau12i $a0, 16
# LE64-NORELAX-NEXT: addi.d $a0, $a0, 696
# LE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# LE64-NORELAX-NEXT: jirl $ra, $ra, 0
# LE64-NORELAX-NEXT: add.d $a2, $a0, $tp

## &.got[c]-. = 0x30288+16 - 0x20250: 0x10 pages, page offset 0x298
## Without R_LARCH_RELAX relocation. No relaxation.
# LE64-NORELAX: 20250: pcalau12i $a0, 16
# LE64-NORELAX-NEXT: addi.d $t0, $zero, 0
# LE64-NORELAX-NEXT: addi.d $a0, $a0, 664
# LE64-NORELAX-NEXT: addi.d $t0, $t0, 1
# LE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# LE64-NORELAX-NEXT: addi.d $t0, $t0, 1
# LE64-NORELAX-NEXT: jirl $ra, $ra, 0
# LE64-NORELAX-NEXT: add.d $a3, $a0, $tp

## &.got[d]-. = 0x30288+32 - 0x20270: 0x10 pages, page offset 0x2a8
# LE64-NORELAX: 20270: pcalau12i $a0, 16
# LE64-NORELAX-NEXT: addi.d $a0, $a0, 680
# LE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# LE64-NORELAX-NEXT: jirl $ra, $ra, 0
# LE64-NORELAX-NEXT: add.d $a4, $a0, $tp

# IE64-RELA: .rela.dyn {
# IE64-RELA-NEXT: 0x30430 R_LARCH_TLS_DESC64 - 0x8
# IE64-RELA-NEXT: 0x30460 R_LARCH_TLS_DESC64 - 0x7FF
# IE64-RELA-NEXT: 0x30440 R_LARCH_TLS_DESC64 c 0x0
# IE64-RELA-NEXT: 0x30450 R_LARCH_TLS_DESC64 d 0x0
# IE64-RELA-NEXT: }
# IE64-RELA: Hex dump of section '.got':
# IE64-RELA-NEXT: 0x00030430 00000000 00000000 00000000 00000000 .
# IE64-RELA-NEXT: 0x00030440 00000000 00000000 00000000 00000000 .
# IE64-RELA-NEXT: 0x00030450 00000000 00000000 00000000 00000000 .
# IE64-RELA-NEXT: 0x00030460 00000000 00000000 00000000 00000000 .

# IE64: .got 00000040 0000000000030430

## a and b are optimized to use LE. c and d are optimized to IE.
## &.got[a]-. = 0x30430 - 0x202f8 = 16462<<2
# IE64: 202f8: pcaddi $a0, 16462
# IE64-NEXT: ld.d $ra, $a0, 0
# IE64-NEXT: jirl $ra, $ra, 0
# IE64-NEXT: add.d $a1, $a0, $tp

## &.got[b]-. = 0x30430+48 - 0x20308: 0x10 pages, page offset 0x460
## R_LARCH_RELAX does not appear in pairs. No relaxation.
# IE64: 20308: pcalau12i $a0, 16
# IE64-NEXT: addi.d $a0, $a0, 1120
# IE64-NEXT: ld.d $ra, $a0, 0
# IE64-NEXT: jirl $ra, $ra, 0
# IE64-NEXT: add.d $a2, $a0, $tp

## &.got[c]-. = 0x30430+16 - 0x2031c: 0x10 pages, page offset 0x440
## Without R_LARCH_RELAX relocation. No relaxation.
# IE64: 2031c: pcalau12i $a0, 16
# IE64-NEXT: addi.d $t0, $zero, 0
# IE64-NEXT: addi.d $a0, $a0, 1088
# IE64-NEXT: addi.d $t0, $t0, 1
# IE64-NEXT: ld.d $ra, $a0, 0
# IE64-NEXT: addi.d $t0, $t0, 1
# IE64-NEXT: jirl $ra, $ra, 0
# IE64-NEXT: add.d $a3, $a0, $tp

## &.got[d]-. = 0x30430+32 - 0x2033c = 16453<<2
# IE64: 2033c: pcaddi $a0, 16453
# IE64-NEXT: ld.d $ra, $a0, 0
# IE64-NEXT: jirl $ra, $ra, 0
# IE64-NEXT: add.d $a4, $a0, $tp

# IE64-NORELAX: .got 00000040 0000000000030438

## &.got[a]-. = 0x30438 - 0x202f8 = 0x10 pages, page offset 0x438
# IE64-NORELAX: 202f8: pcalau12i $a0, 16
# IE64-NORELAX-NEXT: addi.d $a0, $a0, 1080
# IE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# IE64-NORELAX-NEXT: jirl $ra, $ra, 0
# IE64-NORELAX-NEXT: add.d $a1, $a0, $tp

## &.got[b]-. = 0x30438+48 - 0x2030c: 0x10 pages, page offset 0x468
## R_LARCH_RELAX does not appear in pairs. No relaxation.
# IE64-NORELAX: 2030c: pcalau12i $a0, 16
# IE64-NORELAX-NEXT: addi.d $a0, $a0, 1128
# IE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# IE64-NORELAX-NEXT: jirl $ra, $ra, 0
# IE64-NORELAX-NEXT: add.d $a2, $a0, $tp

## &.got[c]-. = 0x30438+16 - 0x20320: 0x10 pages, page offset 0x448
## Without R_LARCH_RELAX relocation. No relaxation.
# IE64-NORELAX: 20320: pcalau12i $a0, 16
# IE64-NORELAX-NEXT: addi.d $t0, $zero, 0
# IE64-NORELAX-NEXT: addi.d $a0, $a0, 1096
# IE64-NORELAX-NEXT: addi.d $t0, $t0, 1
# IE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# IE64-NORELAX-NEXT: addi.d $t0, $t0, 1
# IE64-NORELAX-NEXT: jirl $ra, $ra, 0
# IE64-NORELAX-NEXT: add.d $a3, $a0, $tp

## &.got[d]-. = 0x30438+32 - 0x20340: 0x10 pages, page offset 0x458
# IE64-NORELAX: 20340: pcalau12i $a0, 16
# IE64-NORELAX-NEXT: addi.d $a0, $a0, 1112
# IE64-NORELAX-NEXT: ld.d $ra, $a0, 0
# IE64-NORELAX-NEXT: jirl $ra, $ra, 0
# IE64-NORELAX-NEXT: add.d $a4, $a0, $tp

#--- a.s
la.tls.desc $a0, a
add.d $a1, $a0, $tp

# ADDI.D does not have R_LARCH_RELAX. No relaxation.
pcalau12i $a0, %desc_pc_hi20(b)
.reloc .-4, R_LARCH_RELAX, 0
addi.d $a0, $a0, %desc_pc_lo12(b)
ld.d $ra, $a0, %desc_ld(b)
jirl $ra, $ra, %desc_call(b)
add.d $a2, $a0, $tp

# TLSDESC to LE. No relaxation.
pcalau12i $a0, %desc_pc_hi20(c)
addi.d $t0, $zero, 0
addi.d $a0, $a0, %desc_pc_lo12(c)
addi.d $t0, $t0, 1
ld.d $ra, $a0, %desc_ld(c)
addi.d $t0, $t0, 1
jirl $ra, $ra, %desc_call(c)
add.d $a3, $a0, $tp

# PCALAU12I and ADDI.D have R_LARCH_RELAX. We perform relaxation.
pcalau12i $a0, %desc_pc_hi20(d)
.reloc .-4, R_LARCH_RELAX, 0
addi.d $a0, $a0, %desc_pc_lo12(d)
.reloc .-4, R_LARCH_RELAX, 0
ld.d $ra, $a0, %desc_ld(d)
jirl $ra, $ra, %desc_call(d)
add.d $a4, $a0, $tp

.section .tbss,"awT",@nobits
.globl a
.zero 8
a:
.zero 2039 ## Place b at 0x7ff
b:
.zero 1

#--- c.s
.section .tbss,"awT",@nobits
.globl c, d
c:
.zero 2048 ## Place d at 0x1000
d:
.zero 4