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.

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;

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:

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

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

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

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

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