x86: Count PLT for GOTOFF relocation against IFUNC symbol

Message ID 20210620031119.818920-1-hjl.tools@gmail.com
State New
Headers show
Series
  • x86: Count PLT for GOTOFF relocation against IFUNC symbol
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Commit Message

Alan Modra via Binutils June 20, 2021, 3:11 a.m.
Since GOTOFF relocations against IFUNC symbols must go through PLT,
set PLT reference count to 1 for GOTOFF relocation.

bfd/

	PR ld/27998
	* elfxx-x86.c (elf_x86_allocate_dynrelocs): Count PLT for GOTOFF
	relocation against IFUNC symbols.
	(_bfd_x86_elf_adjust_dynamic_symbol): Likewise.

ld/

	PR ld/27998
	* testsuite/ld-i386/i386.exp: Run PR ld/27998 tests.
	* testsuite/ld-i386/pr27998a.d: New file.
	* testsuite/ld-i386/pr27998a.s: Likewise.
	* testsuite/ld-i386/pr27998b.d: Likewise.
	* testsuite/ld-i386/pr27998b.s: Likewise.
---
 bfd/elfxx-x86.c                 | 12 ++++++++++--
 ld/testsuite/ld-i386/i386.exp   |  2 ++
 ld/testsuite/ld-i386/pr27998a.d |  7 +++++++
 ld/testsuite/ld-i386/pr27998a.s | 22 ++++++++++++++++++++++
 ld/testsuite/ld-i386/pr27998b.d |  7 +++++++
 ld/testsuite/ld-i386/pr27998b.s | 20 ++++++++++++++++++++
 6 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 ld/testsuite/ld-i386/pr27998a.d
 create mode 100644 ld/testsuite/ld-i386/pr27998a.s
 create mode 100644 ld/testsuite/ld-i386/pr27998b.d
 create mode 100644 ld/testsuite/ld-i386/pr27998b.s

-- 
2.31.1

Patch

diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index 62d516aab8d..088f6e5c536 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -131,6 +131,10 @@  elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
   if (h->type == STT_GNU_IFUNC
       && h->def_regular)
     {
+      /* GOTOFF relocation needs PLT.  */
+      if (eh->gotoff_ref)
+	h->plt.refcount = 1;
+
       if (_bfd_elf_allocate_ifunc_dyn_relocs (info, h, &h->dyn_relocs,
 					      plt_entry_size,
 					      (htab->plt.has_plt0
@@ -1818,6 +1822,8 @@  _bfd_x86_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
   const struct elf_backend_data *bed
     = get_elf_backend_data (info->output_bfd);
 
+  eh = (struct elf_x86_link_hash_entry *) h;
+
   /* STT_GNU_IFUNC symbol must go through PLT. */
   if (h->type == STT_GNU_IFUNC)
     {
@@ -1856,6 +1862,10 @@  _bfd_x86_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
 		    h->plt.refcount += 1;
 		}
 	    }
+
+	  /* GOTOFF relocation needs PLT.  */
+	  if (eh->gotoff_ref)
+	    h->plt.refcount = 1;
 	}
 
       if (h->plt.refcount <= 0)
@@ -1896,8 +1906,6 @@  _bfd_x86_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
        the link may change h->type.  So fix it now.  */
     h->plt.offset = (bfd_vma) -1;
 
-  eh = (struct elf_x86_link_hash_entry *) h;
-
   /* If this is a weak symbol, and there is a real definition, the
      processor independent code will have arranged for us to see the
      real definition first, and we can just use the same value.  */
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 3d6047b790d..ceb60002d13 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -519,6 +519,8 @@  run_dump_test "pr19939a"
 run_dump_test "pr19939b"
 run_dump_test "tlsdesc2"
 run_dump_test "report-reloc-1"
+run_dump_test "pr27998a"
+run_dump_test "pr27998b"
 
 proc undefined_weak {cflags ldflags} {
     set testname "Undefined weak symbol"
diff --git a/ld/testsuite/ld-i386/pr27998a.d b/ld/testsuite/ld-i386/pr27998a.d
new file mode 100644
index 00000000000..ca3c9205fa6
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27998a.d
@@ -0,0 +1,7 @@ 
+#as: --32
+#ld: -shared -melf_i386
+#readelf: -r --wide
+
+Relocation section '.rel.plt' at offset 0x[0-9a-f]+ contains 1 entry:
+ Offset     Info    Type                Sym. Value  Symbol's Name
+[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
diff --git a/ld/testsuite/ld-i386/pr27998a.s b/ld/testsuite/ld-i386/pr27998a.s
new file mode 100644
index 00000000000..ec55cd6948a
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27998a.s
@@ -0,0 +1,22 @@ 
+	.text
+	.p2align 4
+	.type	my_foo, @function
+my_foo:
+	ret
+	.size	my_foo, .-my_foo
+	.p2align 4
+	.type	resolve_foo, @function
+resolve_foo:
+	leal	my_foo@GOTOFF(%eax), %eax
+	ret
+	.size	resolve_foo, .-resolve_foo
+	.globl	foo
+	.hidden	foo
+	.type	foo, @gnu_indirect_function
+	.set	foo,resolve_foo
+	.p2align 4
+	.globl	bar
+	.type	bar, @function
+bar:
+	leal	foo@GOTOFF(%eax), %eax
+	ret
diff --git a/ld/testsuite/ld-i386/pr27998b.d b/ld/testsuite/ld-i386/pr27998b.d
new file mode 100644
index 00000000000..ca3c9205fa6
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27998b.d
@@ -0,0 +1,7 @@ 
+#as: --32
+#ld: -shared -melf_i386
+#readelf: -r --wide
+
+Relocation section '.rel.plt' at offset 0x[0-9a-f]+ contains 1 entry:
+ Offset     Info    Type                Sym. Value  Symbol's Name
+[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
diff --git a/ld/testsuite/ld-i386/pr27998b.s b/ld/testsuite/ld-i386/pr27998b.s
new file mode 100644
index 00000000000..8b023e9b12d
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27998b.s
@@ -0,0 +1,20 @@ 
+	.text
+	.p2align 4
+	.type	my_foo, @function
+my_foo:
+	ret
+	.size	my_foo, .-my_foo
+	.p2align 4
+	.type	resolve_foo, @function
+resolve_foo:
+	leal	my_foo@GOTOFF(%eax), %eax
+	ret
+	.size	resolve_foo, .-resolve_foo
+	.type	foo, @gnu_indirect_function
+	.set	foo,resolve_foo
+	.p2align 4
+	.globl	bar
+	.type	bar, @function
+bar:
+	leal	foo@GOTOFF(%eax), %eax
+	ret