Don't complain about -fPIC for undefined symbol

When building executable, undefined symbol is a fatal error.  We don't
complain about -fPIC if the symbol is undefined.

bfd/

	PR ld/17847
	* elf64-x86-64.c (elf_x86_64_relocate_section): Don't complain
	about -fPIC if the symbol is undefined when building executable.

ld/testsuite/

	PR ld/17847
	* ld-x86-64/pie1.d: New file.
	* ld-x86-64/pie1.s: Likwise.
	* ld-x86-64/x86-64.exp: Run pie1.

bfd/ChangeLog

@@ -1,3 +1,9 @@
+2015-01-15  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/17847
+	* elf64-x86-64.c (elf_x86_64_relocate_section): Don't complain
+	about -fPIC if the symbol is undefined when building executable.
+
 2015-01-15  Nick Clifton  <nickc@redhat.com>
 
 	PR binutils/17512

bfd/elf64-x86-64.c

@@ -4063,10 +4063,14 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 	case R_X86_64_PC16:
 	case R_X86_64_PC32:
 	case R_X86_64_PC32_BND:
+	  /* Don't complain about -fPIC if the symbol is undefined when
+	     building executable.  */
 	  if (info->shared
 	      && (input_section->flags & SEC_ALLOC) != 0
 	      && (input_section->flags & SEC_READONLY) != 0
-	      && h != NULL)
+	      && h != NULL
+	      && !(info->executable
+		   && h->root.type == bfd_link_hash_undefined))
 	    {
 	      bfd_boolean fail = FALSE;
 	      bfd_boolean branch
@@ -4140,11 +4144,14 @@ direct:
 	    break;
 
 	   /* Don't copy a pc-relative relocation into the output file
-	      if the symbol needs copy reloc.  */
+	      if the symbol needs copy reloc or the symbol is undefined
+	      when building executable.  */
 	  if ((info->shared
 	       && !(info->executable
 		    && h != NULL
-		    && (h->needs_copy || eh->needs_copy)
+		    && (h->needs_copy
+			|| eh->needs_copy
+			|| h->root.type == bfd_link_hash_undefined)
 		    && IS_X86_64_PCREL_TYPE (r_type))
 	       && (h == NULL
 		   || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT

ld/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2015-01-15  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/17847
+	* ld-x86-64/pie1.d: New file.
+	* ld-x86-64/pie1.s: Likwise.
+	* ld-x86-64/x86-64.exp: Run pie1.
+
 2015-01-13  Thomas Preud'homme <thomas.preudhomme@arm.com>
 
 	* ld-aarch64/aarch64-elf.exp: Added relocs-257-symbolic-func test.

ld/testsuite/ld-x86-64/pie1.d

@@ -0,0 +1,9 @@
+#name: PIE with undefined symbol
+#as: --64
+#ld: -pie -melf_x86_64 --noinhibit-exec
+#readelf: -s --wide
+#warning: \A[^\n]*\.o[^\n]*In function `_start':\n[^\n]*: undefined reference to `foo'\Z
+
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +NOTYPE +GLOBAL +DEFAULT +UND foo
+#pass

ld/testsuite/ld-x86-64/pie1.s

@@ -0,0 +1,4 @@
+	.text
+	.global _start
+_start:
+	movl	foo(%rip), %eax

ld/testsuite/ld-x86-64/x86-64.exp

@@ -228,6 +228,7 @@ run_dump_test "pr12570b"
 run_dump_test "pr14215"
 run_dump_test "pr14207"
 run_dump_test "gotplt1"
+run_dump_test "pie1"
 
 if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
     return