[lld] [llvm] [LoongArch] Use R_LARCH_ALIGN with section symbol (PR #84741)
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Mon Mar 11 03:26:43 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lld
@llvm/pr-subscribers-lld-elf
@llvm/pr-subscribers-mc
@llvm/pr-subscribers-backend-loongarch
Author: Jinyang He (MQ-mengqing)
<details>
<summary>Changes</summary>
In LoongArch psABI v2.30, the R_LARCH_ALIGN requires symbol index to support the third parameter of alignment directive. Create symbol for each section is redundant because they have section symbol which can also be used as symbol index. So use section symbol directly for R_LARCH_ALIGN.
---
Full diff: https://github.com/llvm/llvm-project/pull/84741.diff
6 Files Affected:
- (modified) lld/ELF/InputSection.cpp (+5-1)
- (added) lld/test/ELF/loongarch-relax-align-ldr.s (+27)
- (modified) lld/test/ELF/loongarch-relax-emit-relocs.s (+3-2)
- (modified) llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp (+2-5)
- (modified) llvm/test/MC/LoongArch/Relocations/relax-addsub.s (+1-1)
- (modified) llvm/test/MC/LoongArch/Relocations/relax-align.s (+8-6)
``````````diff
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index e033a715b59214..313a19426a5e20 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -462,7 +462,11 @@ void InputSection::copyRelocations(uint8_t *buf,
addend += sec->getFile<ELFT>()->mipsGp0;
}
- if (RelTy::IsRela)
+ if (config->emachine == EM_LOONGARCH && type == R_LARCH_ALIGN)
+ // LoongArch psABI v2.30, the R_LARCH_ALIGN requires symbol index.
+ // If it use the section symbol, the addend should not be changed.
+ p->r_addend = addend;
+ else if (RelTy::IsRela)
p->r_addend = sym.getVA(addend) - section->getOutputSection()->addr;
// For SHF_ALLOC sections relocated by REL, append a relocation to
// sec->relocations so that relocateAlloc transitively called by
diff --git a/lld/test/ELF/loongarch-relax-align-ldr.s b/lld/test/ELF/loongarch-relax-align-ldr.s
new file mode 100644
index 00000000000000..da4685579b72e5
--- /dev/null
+++ b/lld/test/ELF/loongarch-relax-align-ldr.s
@@ -0,0 +1,27 @@
+# REQUIRES: loongarch
+
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.64.o
+# RUN: ld.lld -r %t.64.o %t.64.o -o %t.64.r
+# RUN: llvm-objdump -dr --no-show-raw-insn %t.64.r | FileCheck %s
+
+# CHECK: <.text>:
+# CHECK-NEXT: break 1
+# CHECK-NEXT: nop
+# CHECK-NEXT: {{0*}}04: R_LARCH_ALIGN .text+0x804
+# CHECK-NEXT: nop
+# CHECK-NEXT: nop
+# CHECK-NEXT: break 2
+# CHECK-NEXT: break 0
+# CHECK-NEXT: break 0
+# CHECK-NEXT: break 0
+# CHECK-NEXT: break 1
+# CHECK-NEXT: nop
+# CHECK-NEXT: {{0*}}24: R_LARCH_ALIGN .text+0x804
+# CHECK-NEXT: nop
+# CHECK-NEXT: nop
+# CHECK-NEXT: break 2
+
+.text
+break 1
+.p2align 4, , 8
+break 2
diff --git a/lld/test/ELF/loongarch-relax-emit-relocs.s b/lld/test/ELF/loongarch-relax-emit-relocs.s
index 581fce8c95caa4..9007f8fcc114f0 100644
--- a/lld/test/ELF/loongarch-relax-emit-relocs.s
+++ b/lld/test/ELF/loongarch-relax-emit-relocs.s
@@ -25,7 +25,7 @@
# CHECK-NEXT: R_LARCH_PCALA_LO12 _start
# CHECK-NEXT: R_LARCH_RELAX *ABS*
# CHECK-NEXT: nop
-# CHECK-NEXT: R_LARCH_ALIGN .Lla-relax-align0+0x4
+# CHECK-NEXT: R_LARCH_ALIGN .text+0x4
# CHECK-NEXT: nop
# CHECK-NEXT: ret
@@ -37,11 +37,12 @@
# CHECKR-NEXT: R_LARCH_PCALA_LO12 _start
# CHECKR-NEXT: R_LARCH_RELAX *ABS*
# CHECKR-NEXT: nop
-# CHECKR-NEXT: R_LARCH_ALIGN .Lla-relax-align0+0x4
+# CHECKR-NEXT: R_LARCH_ALIGN .text+0x4
# CHECKR-NEXT: nop
# CHECKR-NEXT: nop
# CHECKR-NEXT: ret
+.text
.global _start
_start:
la.pcrel $a0, _start
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
index de492f2b1f0a4f..98f5014a34b1de 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
@@ -226,11 +226,8 @@ bool LoongArchAsmBackend::shouldInsertFixupForCodeAlign(
MCFixup::create(0, Dummy, MCFixupKind(LoongArch::fixup_loongarch_align));
const MCSymbolRefExpr *MCSym = getSecToAlignSym()[Sec];
if (MCSym == nullptr) {
- // Create a symbol and make the value of symbol is zero.
- MCSymbol *Sym = Ctx.createNamedTempSymbol("la-relax-align");
- Sym->setFragment(&*Sec->getBeginSymbol()->getFragment());
- Asm.registerSymbol(*Sym);
- MCSym = MCSymbolRefExpr::create(Sym, Ctx);
+ // Use section symbol directly.
+ MCSym = MCSymbolRefExpr::create(Sec->getBeginSymbol(), Ctx);
getSecToAlignSym()[Sec] = MCSym;
}
diff --git a/llvm/test/MC/LoongArch/Relocations/relax-addsub.s b/llvm/test/MC/LoongArch/Relocations/relax-addsub.s
index 18e0ede5e29375..0e27d6301bb3cd 100644
--- a/llvm/test/MC/LoongArch/Relocations/relax-addsub.s
+++ b/llvm/test/MC/LoongArch/Relocations/relax-addsub.s
@@ -28,7 +28,7 @@
# RELAX: Relocations [
# RELAX-NEXT: Section ({{.*}}) .rela.text {
-# RELAX-NEXT: 0x4 R_LARCH_ALIGN {{.*}} 0x4
+# RELAX-NEXT: 0x4 R_LARCH_ALIGN .text 0x4
# RELAX-NEXT: 0x10 R_LARCH_PCALA_HI20 .L1 0x0
# RELAX-NEXT: 0x10 R_LARCH_RELAX - 0x0
# RELAX-NEXT: 0x14 R_LARCH_PCALA_LO12 .L1 0x0
diff --git a/llvm/test/MC/LoongArch/Relocations/relax-align.s b/llvm/test/MC/LoongArch/Relocations/relax-align.s
index 294fd9fb916c75..0246d5b46431c9 100644
--- a/llvm/test/MC/LoongArch/Relocations/relax-align.s
+++ b/llvm/test/MC/LoongArch/Relocations/relax-align.s
@@ -63,17 +63,19 @@ ret
## Test the symbol index is different from .text.
.section .text2, "ax"
.p2align 4
+.p2align 4, , 4
break 7
# RELOC: Relocations [
# RELAX-RELOC-NEXT: Section ({{.*}}) .rela.text {
-# RELAX-RELOC-NEXT: 0x24 R_LARCH_ALIGN .Lla-relax-align0 0x4
-# RELAX-RELOC-NEXT: 0x34 R_LARCH_ALIGN .Lla-relax-align0 0x5
-# RELAX-RELOC-NEXT: 0x50 R_LARCH_ALIGN .Lla-relax-align0 0x4
-# RELAX-RELOC-NEXT: 0x60 R_LARCH_ALIGN .Lla-relax-align0 0xB04
-# RELAX-RELOC-NEXT: 0x70 R_LARCH_ALIGN .Lla-relax-align0 0x4
+# RELAX-RELOC-NEXT: 0x24 R_LARCH_ALIGN .text 0x4
+# RELAX-RELOC-NEXT: 0x34 R_LARCH_ALIGN .text 0x5
+# RELAX-RELOC-NEXT: 0x50 R_LARCH_ALIGN .text 0x4
+# RELAX-RELOC-NEXT: 0x60 R_LARCH_ALIGN .text 0xB04
+# RELAX-RELOC-NEXT: 0x70 R_LARCH_ALIGN .text 0x4
# RELAX-RELOC-NEXT: }
# RELAX-RELOC-NEXT: Section ({{.*}}) .rela.text2 {
-# RELAX-RELOC-NEXT: 0x0 R_LARCH_ALIGN .Lla-relax-align1 0x4
+# RELAX-RELOC-NEXT: 0x0 R_LARCH_ALIGN .text2 0x4
+# RELAX-RELOC-NEXT: 0xC R_LARCH_ALIGN .text2 0x404
# RELAX-RELOC-NEXT: }
# RELOC-NEXT: ]
``````````
</details>
https://github.com/llvm/llvm-project/pull/84741
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