[lld] [lld][ELF] Support relax R_LARCH_{ALIGN, PCALA_{HI20,LO12}, GOT_PC_{HI20,LO12}} (PR #78692)

[Jinyang He via llvm-commits]

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@@ -0,0 +1,137 @@
+# REQUIRES: loongarch
+
+# RUN: llvm-mc --filetype=obj --triple=loongarch32 --mattr=+relax %s -o %t.32.o
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.64.o
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.32.o -o %t.32
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.64.o -o %t.64
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.32.o --no-relax -o %t.32n
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.64.o --no-relax -o %t.64n
+# RUN: llvm-objdump -td --no-show-raw-insn %t.32 | FileCheck %s --check-prefixes=CHECK,RELAX
+# RUN: llvm-objdump -td --no-show-raw-insn %t.64 | FileCheck %s --check-prefixes=CHECK,RELAX
+# RUN: llvm-objdump -td --no-show-raw-insn %t.32n | FileCheck %s --check-prefixes=CHECK,NOREL
+# RUN: llvm-objdump -td --no-show-raw-insn %t.64n | FileCheck %s --check-prefixes=CHECK,NOREL
+
+## Test the R_LARCH_ALIGN without symbol index.
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.o64.o --defsym=old=1
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.o64.o -o %t.o64
+# RUN: ld.lld --section-start=.text=0x10000 --section-start=.text2=0x20000 -e 0 %t.o64.o --no-relax -o %t.o64n
+# RUN: llvm-objdump -td --no-show-raw-insn %t.o64 | FileCheck %s --check-prefixes=CHECK,RELAX
+# RUN: llvm-objdump -td --no-show-raw-insn %t.o64n | FileCheck %s --check-prefixes=CHECK,NOREL
+
+## -r keeps section contents unchanged.
+# RUN: ld.lld -r %t.64.o -o %t.64.r
+# RUN: llvm-objdump -dr --no-show-raw-insn %t.64.r | FileCheck %s --check-prefix=CHECKR
+
+# RELAX-DAG: {{0*}}10000 l .text  {{0*}}34 .Ltext_start
+# RELAX-DAG: {{0*}}1002c l .text  {{0*}}08 .L1
+# RELAX-DAG: {{0*}}10030 l .text  {{0*}}04 .L2
+# RELAX-DAG: {{0*}}20000 l .text2 {{0*}}14 .Ltext2_start
+# NOREL-DAG: {{0*}}10000 l .text  {{0*}}44 .Ltext_start
+# NOREL-DAG: {{0*}}10038 l .text  {{0*}}0c .L1
+# NOREL-DAG: {{0*}}10040 l .text  {{0*}}04 .L2
+# NOREL-DAG: {{0*}}20000 l .text2 {{0*}}14 .Ltext2_start
+
+# CHECK:      <.Ltext_start>:
+# CHECK-NEXT:    10000:      break 1
+# CHECK-NEXT:    10004:      break 2
+# CHECK-NEXT:    10008:      nop
+# CHECK-NEXT:    1000c:      nop
+# CHECK-NEXT:    10010:      break 3
+# CHECK-NEXT:    10014:      break 4
+# CHECK-NEXT:    10018:      nop
+# CHECK-NEXT:    1001c:      nop
+# RELAX-NEXT:    10020:      pcaddi $zero, -8
+# RELAX-NEXT:    10024:      pcaddi $zero, 2
+# RELAX-NEXT:    10028:      pcaddi $zero, 2
+# NOREL-NEXT:    10020:      pcalau12i     $zero, 0
+# NOREL-NEXT:    10024:      addi.{{[dw]}} $zero, $zero, 0
+# NOREL-NEXT:    10028:      pcalau12i     $zero, 0
+# NOREL-NEXT:    1002c:      addi.{{[dw]}} $zero, $zero, 56
+# NOREL-NEXT:    10030:      pcalau12i     $zero, 0
+# NOREL-NEXT:    10034:      addi.{{[dw]}} $zero, $zero, 64
+# CHECK-EMPTY:
+# CHECK-NEXT: <.L1>:
+# RELAX-NEXT:    1002c:      nop
+# NOREL-NEXT:    10038:      nop
+# NOREL-NEXT:    1003c:      nop
+# CHECK-EMPTY:
+# CHECK-NEXT: <.L2>:
+# CHECK-NEXT:    break 5
+
+# CHECK:      <.Ltext2_start>:
+# RELAX-NEXT:    20000:     pcaddi $zero, 0
+# RELAX-NEXT:    20004:     nop
+# NOREL-NEXT:    20000:     pcalau12i     $zero, 0
+# NOREL-NEXT:    20004:     addi.{{[dw]}} $zero, $zero, 0
+# CHECK-NEXT:    20008:     nop
+# CHECK-NEXT:    2000c:     nop
+# CHECK-NEXT:    20010:     break 6
+
+# CHECKR:      <.Ltext2_start>:
+# CHECKR-NEXT:  0:     pcalau12i $zero, 0
+# CHECKR-NEXT:         {{0*}}00: R_LARCH_PCALA_HI20 .Ltext2_start
+# CHECKR-NEXT:         {{0*}}00: R_LARCH_RELAX      *ABS*
+# CHECKR-NEXT:  4:     addi.d    $zero, $zero, 0
+# CHECKR-NEXT:         {{0*}}04: R_LARCH_PCALA_LO12 .Ltext2_start
+# CHECKR-NEXT:         {{0*}}04: R_LARCH_RELAX      *ABS*
+# CHECKR-NEXT:  8:     nop
+# CHECKR-NEXT:         {{0*}}08: R_LARCH_ALIGN      .Lalign_symbol+0x4
+# CHECKR-NEXT:  c:     nop
+# CHECKR-NEXT: 10:     nop
+# CHECKR-NEXT: 14:     break 6
+
+.macro .fake_p2align_4 max=0
+  .ifdef old
+    .ifeq \max!=0
----------------
MQ-mengqing wrote:

```
.ifeq absolute expression
Assembles the following section of code if the argument is zero.
```
It's counter-intuitive. I may miss `.if` in `Using as`, it should be more intuitive. I'll correct it.

https://github.com/llvm/llvm-project/pull/78692