[binutils-gdb] LoongArch: Fix linker generate PLT entry for data symbol

[binutils-gdb] LoongArch: Fix linker generate PLT entry for data symbol

[liu & zhensong]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e493ba6255aec08885affbb68ddc0a025583d528

commit e493ba6255aec08885affbb68ddc0a025583d528
Author: mengqinggang <mengqinggang@loongson.cn>
Date:   Thu Dec 1 17:23:14 2022 +0800

    LoongArch: Fix linker generate PLT entry for data symbol
    
    With old "medium" code model, we call a function with a pair of PCALAU12I
    and JIRL instructions. The assembler produces something like:
    
       8:   1a00000c        pcalau12i       $t0, 0
                            8: R_LARCH_PCALA_HI20   g
       c:   4c000181        jirl            $ra, $t0, 0
                            c: R_LARCH_PCALA_LO12   g
    
    The linker generates a "PLT entry" for data without any diagnostic.
    If "g" is a data symbol and ld with -shared option, it may load two
    instructions in the PLT.
    
    Without -shared option, loongarch_elf_adjust_dynamic_symbol can delete PLT
    entry.
    
    For R_LARCH_PCALA_HI20 relocation, linker only generate PLT entry for STT_FUNC
    and STT_GNU_IFUNC symbols.

Diff:
---
 bfd/elfnn-loongarch.c                              |  6 +++++-
 ld/testsuite/ld-loongarch-elf/data-plt.s           | 20 ++++++++++++++++++
 ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp | 24 ++++++++++++++++++++++
 ld/testsuite/ld-loongarch-elf/libjirl.s            |  1 +
 4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index add916e02f5..2a79e00a12c 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -891,8 +891,12 @@ loongarch_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
 	    h->non_got_ref = 1;
 	  break;
 
+	/* For normal cmodel, pcalau12i + addi.d/w used to data.
+	   For first version medium cmodel, pcalau12i + jirl are used to
+	   function call, it need to creat PLT entry for STT_FUNC and
+	   STT_GNU_IFUNC type symbol.  */
 	case R_LARCH_PCALA_HI20:
-	  if (h != NULL)
+	  if (h != NULL && (STT_FUNC == h->type || STT_GNU_IFUNC == h->type))
 	    {
 	      /* For pcalau12i + jirl.  */
 	      h->needs_plt = 1;
diff --git a/ld/testsuite/ld-loongarch-elf/data-plt.s b/ld/testsuite/ld-loongarch-elf/data-plt.s
new file mode 100644
index 00000000000..faff052c628
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/data-plt.s
@@ -0,0 +1,20 @@
+# The first version medium codel model function call is: pcalau12i + jirl.
+# R_LARCH_PCALA_HI20 only need to generate PLT entry for function symbols.
+	.text
+	.globl	a
+
+	.data
+	.align	2
+	.type	a, @object
+	.size	a, 4
+a:
+	.word	1
+
+	.text
+	.align	2
+	.globl	test
+	.type	test, @function
+test:
+	pcalau12i	$r12,%pc_hi20(a)
+	ld.w	$r12,$r12,%pc_lo12(a)
+	.size	test, .-test
diff --git a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
index 8dc04fea707..64e644d3079 100644
--- a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
+++ b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
@@ -59,6 +59,30 @@ if [istarget "loongarch64-*-*"] {
 	]
   }
 
+  # loongarch*-elf target do not support -shared option
+  if [check_shared_lib_support] {
+    run_ld_link_tests \
+	[list \
+	     [list \
+		  "data plt" \
+		  "-shared" "" \
+		  "" \
+		  {data-plt.s} \
+		  {} \
+		  "data-plt.so" \
+	     ] \
+	]
+
+    if [file exist "tmpdir/data-plt.so"] {
+      set objdump_output [run_host_cmd "objdump" "-d tmpdir/data-plt.so"]
+      if { [ regexp "<a@plt>" $objdump_output] } {
+	fail "data plt"
+      } {
+	pass "data plt"
+      }
+    }
+  }
+
   run_ld_link_tests \
       [list \
 	  [list \
diff --git a/ld/testsuite/ld-loongarch-elf/libjirl.s b/ld/testsuite/ld-loongarch-elf/libjirl.s
index 4d963870df0..de028c5a44b 100644
--- a/ld/testsuite/ld-loongarch-elf/libjirl.s
+++ b/ld/testsuite/ld-loongarch-elf/libjirl.s
@@ -1,2 +1,3 @@
+.type func @function
 pcalau12i $r12, %pc_hi20(func)
 jirl $r1,$r12, %pc_lo12(func)