LoongArch: Add relaxation for R_LARCH_CALL36

This relaxation is effective for both macro instructions (call36, tail36)
and explicit relocation instructions (pcaddu18i + jirl).

call36 f	  ->	bl f
  R_LARCH_CALL36  ->	  R_LARCH_B26

tail36 $t0, f	  ->	b f
  R_LARCH_CALL36  ->	  R_LARCH_B26

5 files changed, 122 insertions, 0 deletions

diff --git a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
index 507b244..759acab 100644
--- a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
+++ b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
@@ -52,6 +52,8 @@ if [istarget "loongarch64-*-*"] {
     run_dump_test "underflow_s_5_20"
     run_dump_test "tls-le-norelax"
     run_dump_test "tls-le-relax"
+    run_dump_test "relax-medium-call"
+    run_dump_test "relax-medium-call-1"
 }
 
 if [istarget "loongarch32-*-*"] {
diff --git a/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.d b/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.d
new file mode 100644
index 0000000..c8ee933
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.d
@@ -0,0 +1,21 @@
+#ld: -e0 -Ttext=0x120000000 --section-start=ta=0x118000000 --section-start=tb=0x127fffffc
+#objdump: -d -j .text
+
+.*:[    ]+file format .*
+
+
+Disassembly of section .text:
+
+[ 	]*0000000120000000 <__bss_start-0x4030>:
+[ 	]+120000000:[ 	]+54000200[ 	]+bl[ 	]+-134217728[ 	]+# 118000000 <a>
+[ 	]+120000004:[ 	]+1fffc001[ 	]+pcaddu18i[ 	]+\$ra, -512
+[ 	]+120000008:[ 	]+4ffffc21[ 	]+jirl[ 	]+\$ra, \$ra, -4
+[ 	]+12000000c:[ 	]+50000200[ 	]+b[ 	]+-134217728[ 	]+# 11800000c <b>
+[ 	]+120000010:[ 	]+1fffc00c[ 	]+pcaddu18i[ 	]+\$t0, -512
+[ 	]+120000014:[ 	]+4ffffd80[ 	]+jirl[ 	]+\$zero, \$t0, -4
+[ 	]+120000018:[ 	]+1e004001[ 	]+pcaddu18i[ 	]+\$ra, 512
+[ 	]+12000001c:[ 	]+4c000421[ 	]+jirl[ 	]+\$ra, \$ra, 4
+[ 	]+120000020:[ 	]+57fffdff[ 	]+bl[ 	]+134217724[ 	]+# 12800001c <c>
+[ 	]+120000024:[ 	]+1e00400c[ 	]+pcaddu18i[ 	]+\$t0, 512
+[ 	]+120000028:[ 	]+4c000580[ 	]+jirl[ 	]+\$zero, \$t0, 4
+[ 	]+12000002c:[ 	]+53fffdff[ 	]+b[ 	]+134217724[ 	]+# 128000028 <d>
diff --git a/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.s b/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.s
new file mode 100644
index 0000000..5266fda
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-medium-call-1.s
@@ -0,0 +1,43 @@
+.section "ta", "ax"
+a:
+  ret
+  ret
+  ret
+b:
+  ret
+
+.text
+  pcaddu18i $ra, %call36(a) # min offset, can relax
+  jirl	    $ra, $ra, 0
+  pcaddu18i $ra, %call36(a) # overflow, not relax
+  jirl	    $ra, $ra, 0
+  pcaddu18i $t0, %call36(b) # min offset, can relax
+  jirl	    $zero, $t0, 0
+  pcaddu18i $t0, %call36(b) # overflow, not relax
+  jirl	    $zero, $t0, 0
+
+  pcaddu18i $ra, %call36(c) # overflow, not relax
+  jirl	    $ra, $ra, 0
+  pcaddu18i $ra, %call36(c) # max offset, can relax
+  jirl	    $ra, $ra, 0
+  pcaddu18i $t0, %call36(d) # overflow, no relax
+  jirl	    $zero, $t0, 0
+  pcaddu18i $t0, %call36(d) # max offset, can relax
+  jirl	    $zero, $t0, 0
+
+.section "tb", "ax"
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+c:
+  ret
+  ret
+  ret
+d:
+  ret
+
diff --git a/ld/testsuite/ld-loongarch-elf/relax-medium-call.d b/ld/testsuite/ld-loongarch-elf/relax-medium-call.d
new file mode 100644
index 0000000..c8ee933
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-medium-call.d
@@ -0,0 +1,21 @@
+#ld: -e0 -Ttext=0x120000000 --section-start=ta=0x118000000 --section-start=tb=0x127fffffc
+#objdump: -d -j .text
+
+.*:[    ]+file format .*
+
+
+Disassembly of section .text:
+
+[ 	]*0000000120000000 <__bss_start-0x4030>:
+[ 	]+120000000:[ 	]+54000200[ 	]+bl[ 	]+-134217728[ 	]+# 118000000 <a>
+[ 	]+120000004:[ 	]+1fffc001[ 	]+pcaddu18i[ 	]+\$ra, -512
+[ 	]+120000008:[ 	]+4ffffc21[ 	]+jirl[ 	]+\$ra, \$ra, -4
+[ 	]+12000000c:[ 	]+50000200[ 	]+b[ 	]+-134217728[ 	]+# 11800000c <b>
+[ 	]+120000010:[ 	]+1fffc00c[ 	]+pcaddu18i[ 	]+\$t0, -512
+[ 	]+120000014:[ 	]+4ffffd80[ 	]+jirl[ 	]+\$zero, \$t0, -4
+[ 	]+120000018:[ 	]+1e004001[ 	]+pcaddu18i[ 	]+\$ra, 512
+[ 	]+12000001c:[ 	]+4c000421[ 	]+jirl[ 	]+\$ra, \$ra, 4
+[ 	]+120000020:[ 	]+57fffdff[ 	]+bl[ 	]+134217724[ 	]+# 12800001c <c>
+[ 	]+120000024:[ 	]+1e00400c[ 	]+pcaddu18i[ 	]+\$t0, 512
+[ 	]+120000028:[ 	]+4c000580[ 	]+jirl[ 	]+\$zero, \$t0, 4
+[ 	]+12000002c:[ 	]+53fffdff[ 	]+b[ 	]+134217724[ 	]+# 128000028 <d>
diff --git a/ld/testsuite/ld-loongarch-elf/relax-medium-call.s b/ld/testsuite/ld-loongarch-elf/relax-medium-call.s
new file mode 100644
index 0000000..c0521b6
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/relax-medium-call.s
@@ -0,0 +1,35 @@
+.section "ta", "ax"
+a:
+  ret
+  ret
+  ret
+b:
+  ret
+
+.text
+  call36 a	# min offset, can relax
+  call36 a	# overflow, not relax
+  tail36 $t0, b	# min offset, can relax
+  tail36 $t0, b	# overflow, not relax
+
+  call36 c	# overflow, not relax
+  call36 c	# max offset, can relax
+  tail36 $t0, d	# overflow, no relax
+  tail36 $t0, d # max offset, can relax
+
+.section "tb", "ax"
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+  ret
+c:
+  ret
+  ret
+  ret
+d:
+  ret
+