[binutils-gdb] i386: Don't allow GOTOFF relocation against IFUNC symbol for PIC

[binutils-gdb] i386: Don't allow GOTOFF relocation against IFUNC symbol for PIC

[H.J. Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=8f29211c3f0a6335c17e0a90396c146facf6dba4

commit 8f29211c3f0a6335c17e0a90396c146facf6dba4
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Jul 21 10:35:58 2022 -0700

    i386: Don't allow GOTOFF relocation against IFUNC symbol for PIC
    
    We can't use the PLT entry as the function address for PIC since the PIC
    register may not be set up properly for indirect call.
    
    bfd/
    
            PR ld/27998
            * elf32-i386.c (elf_i386_relocate_section): Don't allow GOTOFF
            relocation against IFUNC symbol for PIC.
    
    ld/
    
            PR ld/27998
            * testsuite/ld-i386/pr27998a.d: Replace -shared with -e bar.
            * testsuite/ld-i386/pr27998b.d: Expect a linker error.
            * testsuite/ld-ifunc/ifunc-2-i386-now.d: Updated.
            * testsuite/ld-ifunc/ifunc-2-local-i386-now.d: Likewise.
            * testsuite/ld-ifunc/ifunc-2-i386.s: Replace @GOTOFF with @GOT.
            * testsuite/ld-ifunc/ifunc-2-local-i386.s: Likewise.

Diff:
---
 bfd/elf32-i386.c                               | 5 +++++
 ld/testsuite/ld-i386/pr27998a.d                | 2 +-
 ld/testsuite/ld-i386/pr27998b.d                | 6 +-----
 ld/testsuite/ld-ifunc/ifunc-2-i386-now.d       | 2 +-
 ld/testsuite/ld-ifunc/ifunc-2-i386.s           | 2 +-
 ld/testsuite/ld-ifunc/ifunc-2-local-i386-now.d | 2 +-
 ld/testsuite/ld-ifunc/ifunc-2-local-i386.s     | 2 +-
 7 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index cfb0085b245..52b1db44546 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -2460,6 +2460,11 @@ elf_i386_relocate_section (bfd *output_bfd,
 	      goto do_relocation;
 
 	    case R_386_GOTOFF:
+	      /* NB: We can't use the PLT entry as the function address
+		 for PIC since the PIC register may not be set up
+		 properly for indirect call. */
+	      if (bfd_link_pic (info))
+		goto bad_ifunc_reloc;
 	      relocation -= (gotplt->output_section->vma
 			     + gotplt->output_offset);
 	      goto do_relocation;
diff --git a/ld/testsuite/ld-i386/pr27998a.d b/ld/testsuite/ld-i386/pr27998a.d
index ca3c9205fa6..a8019730ec1 100644
--- a/ld/testsuite/ld-i386/pr27998a.d
+++ b/ld/testsuite/ld-i386/pr27998a.d
@@ -1,5 +1,5 @@
 #as: --32
-#ld: -shared -melf_i386
+#ld: -e bar -melf_i386
 #readelf: -r --wide
 
 Relocation section '.rel.plt' at offset 0x[0-9a-f]+ contains 1 entry:
diff --git a/ld/testsuite/ld-i386/pr27998b.d b/ld/testsuite/ld-i386/pr27998b.d
index ca3c9205fa6..8f81edbe8df 100644
--- a/ld/testsuite/ld-i386/pr27998b.d
+++ b/ld/testsuite/ld-i386/pr27998b.d
@@ -1,7 +1,3 @@
 #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 +
+#error: relocation R_386_GOTOFF against STT_GNU_IFUNC symbol `foo' isn't supported
diff --git a/ld/testsuite/ld-ifunc/ifunc-2-i386-now.d b/ld/testsuite/ld-ifunc/ifunc-2-i386-now.d
index a5c56b5a8e3..8d9e8dc988f 100644
--- a/ld/testsuite/ld-ifunc/ifunc-2-i386-now.d
+++ b/ld/testsuite/ld-ifunc/ifunc-2-i386-now.d
@@ -31,6 +31,6 @@ Disassembly of section .text:
  +[a-f0-9]+:	5b                   	pop    %ebx
  +[a-f0-9]+:	81 c3 9e 10 00 00    	add    \$0x109e,%ebx
  +[a-f0-9]+:	e8 de ff ff ff       	call   100 <\*ABS\*@plt>
- +[a-f0-9]+:	8d 83 4c ef ff ff    	lea    -0x10b4\(%ebx\),%eax
+ +[a-f0-9]+:	8b 83 0c 00 00 00    	mov    0xc\(%ebx\),%eax
  +[a-f0-9]+:	c3                   	ret
 #pass
diff --git a/ld/testsuite/ld-ifunc/ifunc-2-i386.s b/ld/testsuite/ld-ifunc/ifunc-2-i386.s
index e84d6b7b5cc..1acf6847e0b 100644
--- a/ld/testsuite/ld-ifunc/ifunc-2-i386.s
+++ b/ld/testsuite/ld-ifunc/ifunc-2-i386.s
@@ -16,6 +16,6 @@ bar:
 	popl	%ebx
 	addl	$_GLOBAL_OFFSET_TABLE_+[.-.L6], %ebx
 	call	__GI_foo@PLT
-	leal	__GI_foo@GOTOFF(%ebx), %eax
+	movl	__GI_foo@GOT(%ebx), %eax
 	ret
 	.size	bar, .-bar
diff --git a/ld/testsuite/ld-ifunc/ifunc-2-local-i386-now.d b/ld/testsuite/ld-ifunc/ifunc-2-local-i386-now.d
index ff494decbdd..9da37e51db7 100644
--- a/ld/testsuite/ld-ifunc/ifunc-2-local-i386-now.d
+++ b/ld/testsuite/ld-ifunc/ifunc-2-local-i386-now.d
@@ -31,6 +31,6 @@ Disassembly of section .text:
  +[a-f0-9]+:	5b                   	pop    %ebx
  +[a-f0-9]+:	81 c3 9e 10 00 00    	add    \$0x109e,%ebx
  +[a-f0-9]+:	e8 de ff ff ff       	call   f0 <\*ABS\*@plt>
- +[a-f0-9]+:	8d 83 4c ef ff ff    	lea    -0x10b4\(%ebx\),%eax
+ +[a-f0-9]+:	8b 83 0c 00 00 00    	mov    0xc\(%ebx\),%eax
  +[a-f0-9]+:	c3                   	ret
 #pass
diff --git a/ld/testsuite/ld-ifunc/ifunc-2-local-i386.s b/ld/testsuite/ld-ifunc/ifunc-2-local-i386.s
index a69e060ddc0..54e0e179551 100644
--- a/ld/testsuite/ld-ifunc/ifunc-2-local-i386.s
+++ b/ld/testsuite/ld-ifunc/ifunc-2-local-i386.s
@@ -13,6 +13,6 @@ bar:
 	popl	%ebx
 	addl	$_GLOBAL_OFFSET_TABLE_+[.-.L6], %ebx
 	call	__GI_foo@PLT
-	leal	__GI_foo@GOTOFF(%ebx), %eax
+	movl	__GI_foo@GOT(%ebx), %eax
 	ret
 	.size	bar, .-bar