i386/x86-64: Add unwind info for .plt.got section

When there are both PLT and GOT references to the same function symbol,
linker combines GOTPLT and GOT slots into a single GOT slot and create
an entry in .plt.got section for PLT access via the GOT slot.  This
patch adds unwind info for .plt.got section.

bfd/

	PR ld/20830
	* elf32-i386.c (elf_i386_eh_frame_plt_got): New.
	(PLT_GOT_FDE_LENGTH): Likewise.
	(elf_i386_plt_layout): Add eh_frame_plt_got and
	eh_frame_plt_got_size.
	(elf_i386_plt): Updated.
	(elf_i386_link_hash_table): Add plt_got_eh_frame.
	(elf_i386_check_relocs): Create .eh_frame section for .plt.got.
	(elf_i386_size_dynamic_sections): Allocate and initialize
	.eh_frame section for .plt.got.
	(elf_i386_finish_dynamic_sections): Adjust .eh_frame section for
	.plt.got.
	(elf_i386_nacl_plt): Add FIXME for eh_frame_plt_got and
	eh_frame_plt_got_size.
	* elf64-x86-64.c (elf_x86_64_eh_frame_plt_got): New.
	(PLT_GOT_FDE_LENGTH): Likewise.
	(elf_x86_64_backend_data): Add eh_frame_plt_got and
	eh_frame_plt_got_size.
	(elf_x86_64_arch_bed): Updated.
	(elf_x86_64_bnd_arch_bed): Add FIXME for eh_frame_plt_got and
	eh_frame_plt_got_size.
	(elf_x86_64_nacl_arch_bed): Likewise.
	(elf_x86_64_link_hash_table): Add plt_got_eh_frame.
	(elf_x86_64_check_relocs): Create .eh_frame section for .plt.got.
	(elf_x86_64_size_dynamic_sections): Allocate and initialize
	.eh_frame section for .plt.got.
	(elf_x86_64_finish_dynamic_sections): Adjust .eh_frame section
	for .plt.got.

ld/

	PR ld/20830
	* testsuite/ld-i386/i386.exp: Run pr20830.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr20830.d: New file.
	* testsuite/ld-i386/pr20830.s: Likewise.
	* testsuite/ld-x86-64/pr20830.d: Likewise.
	* testsuite/ld-x86-64/pr20830.s: Likewise.

3 files changed, 80 insertions, 0 deletions

diff --git a/ld/testsuite/ld-x86-64/pr20830.d b/ld/testsuite/ld-x86-64/pr20830.d
new file mode 100644
index 0000000..2dc0f30
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr20830.d
@@ -0,0 +1,71 @@
+#name: PR ld/20830 (.plt.got)
+#as: --64
+#ld: -melf_x86_64 -shared -z relro --ld-generated-unwind-info
+#objdump: -dw -Wf
+
+.*: +file format .*
+
+Contents of the .eh_frame section:
+
+0+ 0000000000000014 00000000 CIE
+  Version:               1
+  Augmentation:          "zR"
+  Code alignment factor: 1
+  Data alignment factor: -8
+  Return address column: 16
+  Augmentation data:     1b
+
+  DW_CFA_def_cfa: r7 \(rsp\) ofs 8
+  DW_CFA_offset: r16 \(rip\) at cfa-8
+  DW_CFA_nop
+  DW_CFA_nop
+
+0+18 0000000000000014 0000001c FDE cie=00000000 pc=0000000000000238..0000000000000244
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+
+0+30 0000000000000024 00000034 FDE cie=00000000 pc=0000000000000220..0000000000000230
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_advance_loc: 6 to 0000000000000226
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_advance_loc: 10 to 0000000000000230
+  DW_CFA_def_cfa_expression \(DW_OP_breg7 \(rsp\): 8; DW_OP_breg16 \(rip\): 0; DW_OP_lit15; DW_OP_and; DW_OP_lit11; DW_OP_ge; DW_OP_lit3; DW_OP_shl; DW_OP_plus\)
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+
+0+58 0000000000000014 0000005c FDE cie=00000000 pc=0000000000000230..0000000000000238
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+  DW_CFA_nop
+
+
+Disassembly of section .plt:
+
+0+220 <.plt>:
+ +[a-f0-9]+:	ff 35 e2 0d 20 00    	pushq  0x200de2\(%rip\)        # 201008 <_GLOBAL_OFFSET_TABLE_\+0x8>
+ +[a-f0-9]+:	ff 25 e4 0d 20 00    	jmpq   \*0x200de4\(%rip\)        # 201010 <_GLOBAL_OFFSET_TABLE_\+0x10>
+ +[a-f0-9]+:	0f 1f 40 00          	nopl   0x0\(%rax\)
+
+Disassembly of section .plt.got:
+
+0+230 <.plt.got>:
+ +[a-f0-9]+:	ff 25 c2 0d 20 00    	jmpq   \*0x200dc2\(%rip\)        # 200ff8 <func>
+ +[a-f0-9]+:	66 90                	xchg   %ax,%ax
+
+Disassembly of section .text:
+
+0+238 <foo>:
+ +[a-f0-9]+:	e8 f3 ff ff ff       	callq  230 <.plt.got>
+ +[a-f0-9]+:	48 8b 05 b4 0d 20 00 	mov    0x200db4\(%rip\),%rax        # 200ff8 <func>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr20830.s b/ld/testsuite/ld-x86-64/pr20830.s
new file mode 100644
index 0000000..d9a1b4c
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr20830.s
@@ -0,0 +1,8 @@
+	.text
+	.globl foo
+	.type foo, @function
+foo:
+	.cfi_startproc
+	call	func@plt
+	movq	func@GOTPCREL(%rip), %rax
+	.cfi_endproc
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 26d739e..878e28e 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -1019,3 +1019,4 @@ if { ![istarget "x86_64-*-linux*"]} {
 run_dump_test "pr17618"
 run_dump_test "pltgot-1"
 run_dump_test "pltgot-2"
+run_dump_test "pr20830"