x86-64: Use PLT address for PC-relative reloc

Since PLT in PDE and PC-relative PLT in PIE can be used as function
address, there is no need for dynamic PC-relative relocation against
a dynamic function definition in PIE.  Linker should resolve PC-relative
reference to its PLT address.

NB: i386 has non-PIC PLT and PIC PLT.  Only non-PIC PLT in PDE can
be used as function address.  PIC PLT in PIE can't be used as
function address.

bfd/

	PR ld/22842
	* elf32-i386.c (elf_i386_check_relocs): Pass FALSE for non
	PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
	* elf64-x86-64.c (elf_x86_64_check_relocs): Create PLT for
	R_X86_64_PC32 reloc against dynamic function in data section.
	Pass TRUE for PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
	(elf_x86_64_relocate_section): Use PLT for R_X86_64_PC32 reloc
	against dynamic function in data section.
	* elfxx-x86.c (elf_x86_allocate_dynrelocs): Use PLT in PIE as
	function address only if pcrel_plt is true.
	(_bfd_x86_elf_link_hash_table_create): Set pcrel_plt.
	* elfxx-x86.h (NEED_DYNAMIC_RELOCATION_P): Add PCREL_PLT for
	PC-relative PLT.  If PLT is PC-relative, don't generate dynamic
	PC-relative relocation against a function definition in data
	secton in PIE.  Remove the obsolete comments.
	(elf_x86_link_hash_table): Add pcrel_plt.

ld/

	PR ld/22842
	* testsuite/ld-i386/i386.exp: Run PR ld/22842 tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr22842a.c: New file.
	* testsuite/ld-i386/pr22842b.S: Likewise.
	* testsuite/ld-x86-64/pr22842a.c: Likewise.
	* testsuite/ld-x86-64/pr22842a.rd: Likewise.
	* testsuite/ld-x86-64/pr22842b.S: Likewise.
	* testsuite/ld-x86-64/pr22842b.rd: Likewise.

9 files changed, 162 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 42ddf8b..c8a967a 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,15 @@
+2018-02-14  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/22842
+	* testsuite/ld-i386/i386.exp: Run PR ld/22842 tests.
+	* testsuite/ld-x86-64/x86-64.exp: Likewise.
+	* testsuite/ld-i386/pr22842a.c: New file.
+	* testsuite/ld-i386/pr22842b.S: Likewise.
+	* testsuite/ld-x86-64/pr22842a.c: Likewise.
+	* testsuite/ld-x86-64/pr22842a.rd: Likewise.
+	* testsuite/ld-x86-64/pr22842b.S: Likewise.
+	* testsuite/ld-x86-64/pr22842b.rd: Likewise.
+
 2018-02-14  Maciej W. Rozycki  <macro@mips.com>
 
 	* ldlex.h (ldlex_command): Remove prototype.
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index e4ec07d..ba2cce8 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -1273,6 +1273,14 @@ if { [isnative]
 	    {} \
 	    "pr21997-1.so" \
 	] \
+	[list \
+	    "Build pr22842.so" \
+	    "-shared" \
+	    "-fPIC" \
+	    { pr22842a.c } \
+	    {} \
+	    "pr22842.so" \
+	] \
     ]
 
     run_ld_link_exec_tests [list \
@@ -1371,6 +1379,14 @@ if { [isnative]
 	    "pr21997-1-pie-2" \
 	    "pass.out" \
 	] \
+	[list \
+	    "Build pr22842" \
+	    "-pie -Wl,--no-as-needed tmpdir/pr22842.so" \
+	    "" \
+	    { pr22842b.S } \
+	    "pr22842" \
+	    "pass.out" \
+	] \
     ]
 
     if { [at_least_gcc_version 5 0] } {
diff --git a/ld/testsuite/ld-i386/pr22842a.c b/ld/testsuite/ld-i386/pr22842a.c
new file mode 100644
index 0000000..52489bb
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr22842a.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void
+test (void)
+{
+  static int count;
+  if (count)
+    printf("PASS\n");
+  count++;
+}
+
+void
+foo (void (*bar) (void))
+{
+  if (bar != test)
+    abort ();
+  bar ();
+  test ();
+}
diff --git a/ld/testsuite/ld-i386/pr22842b.S b/ld/testsuite/ld-i386/pr22842b.S
new file mode 100644
index 0000000..d959a5f
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr22842b.S
@@ -0,0 +1,41 @@
+	.text
+	.globl	main
+	.type	main, @function
+main:
+	leal	4(%esp), %ecx
+	andl	$-16, %esp
+	pushl	-4(%ecx)
+	pushl	%ebp
+	movl	%esp, %ebp
+	pushl	%ebx
+	pushl	%ecx
+	call	__x86.get_pc_thunk.bx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
+	subl	$12, %esp
+	movl	bar@GOT(%ebx), %eax
+	addl	(%eax), %eax
+	pushl	%eax
+	call	foo@PLT
+	addl	$16, %esp
+	leal	-8(%ebp), %esp
+	xorl	%eax, %eax
+	popl	%ecx
+	popl	%ebx
+	popl	%ebp
+	leal	-4(%ecx), %esp
+	ret
+	.size	main, .-main
+	.section	.text.__x86.get_pc_thunk.bx,"axG",@progbits,__x86.get_pc_thunk.bx,comdat
+	.globl	__x86.get_pc_thunk.bx
+	.hidden	__x86.get_pc_thunk.bx
+	.type	__x86.get_pc_thunk.bx, @function
+__x86.get_pc_thunk.bx:
+	movl	(%esp), %ebx
+	ret
+
+	.data
+	.p2align 2
+bar:
+	.long	test - .
+
+	.section	.note.GNU-stack,"",@progbits
diff --git a/ld/testsuite/ld-x86-64/pr22842a.c b/ld/testsuite/ld-x86-64/pr22842a.c
new file mode 100644
index 0000000..52489bb
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr22842a.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void
+test (void)
+{
+  static int count;
+  if (count)
+    printf("PASS\n");
+  count++;
+}
+
+void
+foo (void (*bar) (void))
+{
+  if (bar != test)
+    abort ();
+  bar ();
+  test ();
+}
diff --git a/ld/testsuite/ld-x86-64/pr22842a.rd b/ld/testsuite/ld-x86-64/pr22842a.rd
new file mode 100644
index 0000000..d78ea2f
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr22842a.rd
@@ -0,0 +1,4 @@
+#failif
+#...
+[0-9a-f ]+R_X86_64_NONE.*
+#...
diff --git a/ld/testsuite/ld-x86-64/pr22842b.S b/ld/testsuite/ld-x86-64/pr22842b.S
new file mode 100644
index 0000000..f0659cd
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr22842b.S
@@ -0,0 +1,20 @@
+	.text
+	.globl	main
+	.type	main,@function
+main:
+	pushq	%rax
+        movslq  bar(%rip), %rax
+        leaq    bar(%rip), %rdi
+	addq	%rax, %rdi
+
+	callq	foo
+	xorl	%eax, %eax
+	popq	%rcx
+	retq
+
+	.data
+	.p2align 2
+bar:
+	.long	test - .
+
+	.section	.note.GNU-stack,"",@progbits
diff --git a/ld/testsuite/ld-x86-64/pr22842b.rd b/ld/testsuite/ld-x86-64/pr22842b.rd
new file mode 100644
index 0000000..f1036d5
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr22842b.rd
@@ -0,0 +1,4 @@
+#failif
+#...
+[0-9a-f ]+R_X86_64_PC32 +[0-9a-f]+ +test \+ 0
+#...
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 8442663..2a46266 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -1190,6 +1190,23 @@ if { [isnative] && [which $CC] != 0 } {
 	    {{readelf -drW pr22791-2.rd}} \
 	    "pr22791-2" \
 	] \
+	[list \
+	    "Build pr22842.so" \
+	    "-shared" \
+	    "-fPIC" \
+	    { pr22842a.c } \
+	    {} \
+	    "pr22842.so" \
+	] \
+	[list \
+	    "Build pr22842" \
+	    "-pie -Wl,--no-as-needed tmpdir/pr22842.so" \
+	    "" \
+	    { pr22842b.S } \
+	    {{readelf -rW pr22842a.rd} \
+	     {readelf -rW pr22842b.rd}} \
+	    "pr22842" \
+	] \
     ]
 
     if  {[istarget "x86_64-*-linux*-gnux32"]} {
@@ -1524,6 +1541,14 @@ if { [isnative] && [which $CC] != 0 } {
 	    "pass.out" \
 	    "$NOPIE_CFLAGS" \
 	] \
+	[list \
+	    "Build pr22842" \
+	    "-pie -Wl,--no-as-needed tmpdir/pr22842.so" \
+	    "" \
+	    { pr22842b.S } \
+	    "pr22842" \
+	    "pass.out" \
+	] \
     ]
 
     # Run-time tests which require working ifunc attribute support.