x86: Skip __[start|stop]_SECNAME for --gc-sections -z start-stop-gc

Don't convert memory load to immediate load on __start_SECNAME and
__stop_SECNAME for --gc-sections -z start-stop-gc if all SECNAME
sections been garbage collected.

bfd/

	PR ld/27491
	* elf32-i386.c (elf_i386_convert_load_reloc): Skip __start_SECNAME
	and __stop_SECNAME for --gc-sections -z start-stop-gc if the input
	section been garbage collected.
	* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Likewise.
	* elfxx-x86.h (elf_x86_start_stop_gc_p): New function.

ld/
	PR ld/27491
	* testsuite/ld-i386/i386.exp: Run PR ld/27491 tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr27491-1.s: New file.
	* testsuite/ld-i386/pr27491-1a.d: Likewise.
	* testsuite/ld-i386/pr27491-1b.d: Likewise.
	* testsuite/ld-i386/pr27491-1c.d: Likewise.
	* testsuite/ld-i386/pr27491-2.d: Likewise.
	* testsuite/ld-i386/pr27491-2.s: Likewise.
	* testsuite/ld-i386/pr27491-3.d: Likewise.
	* testsuite/ld-i386/pr27491-3.s: Likewise.
	* testsuite/ld-i386/pr27491-4.d: Likewise.
	* testsuite/ld-i386/pr27491-4a.s: Likewise.
	* testsuite/ld-i386/pr27491-4b.s: Likewise.
	* testsuite/ld-x86-64/pr27491-1.s: Likewise.
	* testsuite/ld-x86-64/pr27491-1a.d: Likewise.
	* testsuite/ld-x86-64/pr27491-1b.d: Likewise.
	* testsuite/ld-x86-64/pr27491-1c.d: Likewise.
	* testsuite/ld-x86-64/pr27491-2.d: Likewise.
	* testsuite/ld-x86-64/pr27491-2.s: Likewise.
	* testsuite/ld-x86-64/pr27491-3.d: Likewise.
	* testsuite/ld-x86-64/pr27491-3.s: Likewise.
	* testsuite/ld-x86-64/pr27491-4.d: Likewise.
	* testsuite/ld-x86-64/pr27491-4a.s: Likewise.
	* testsuite/ld-x86-64/pr27491-4b.s: Likewise.

12 files changed, 180 insertions, 0 deletions

diff --git a/ld/testsuite/ld-x86-64/pr27491-1.s b/ld/testsuite/ld-x86-64/pr27491-1.s
new file mode 100644
index 0000000..0d5b771
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-1.s
@@ -0,0 +1,14 @@
+	.weak __start_xx
+	.weak __stop_xx
+
+	.text
+	.global foo
+foo:
+	movq	__start_xx@gotpcrel(%rip), %rax
+	movq	__stop_xx@gotpcrel(%rip), %rax
+
+	.section xx,"a",unique,0
+	.byte 0
+
+	.section xx,"a",unique,1
+	.byte 1
diff --git a/ld/testsuite/ld-x86-64/pr27491-1a.d b/ld/testsuite/ld-x86-64/pr27491-1a.d
new file mode 100644
index 0000000..ade5c6f
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-1a.d
@@ -0,0 +1,14 @@
+#source: pr27491-1.s
+#as: --64
+#ld: --gc-sections -melf_x86_64 -z start-stop-gc -shared
+#objdump: -dw
+
+.*: +file format elf64-x86-64
+
+
+Disassembly of section .text:
+
+[a-f0-9]+ <foo>:
+ +[a-f0-9]+:	48 8b 05 ([0-9a-f]{2} ){4}[ \t]+mov +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
+ +[a-f0-9]+:	48 8b 05 ([0-9a-f]{2} ){4}[ \t]+mov +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-1b.d b/ld/testsuite/ld-x86-64/pr27491-1b.d
new file mode 100644
index 0000000..a6e21da
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-1b.d
@@ -0,0 +1,11 @@
+#source: pr27491-1.s
+#as: --64
+#ld: --gc-sections -melf_x86_64 -z start-stop-gc -shared
+#nm: -n
+
+#failif
+#...
+[a-f0-9]+ R __start_xx
+#...
+[a-f0-9]+ R __stop_xx
+#...
diff --git a/ld/testsuite/ld-x86-64/pr27491-1c.d b/ld/testsuite/ld-x86-64/pr27491-1c.d
new file mode 100644
index 0000000..1288361
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-1c.d
@@ -0,0 +1,21 @@
+#source: pr27491-1.s
+#as: --64
+#ld: --gc-sections -melf_x86_64 -shared
+#objdump: --syms -dw
+
+.*: +file format elf64-x86-64
+
+SYMBOL TABLE:
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __stop_xx
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __start_xx
+#...
+
+
+Disassembly of section .text:
+
+[a-f0-9]+ <foo>:
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__start_xx>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__stop_xx>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-2.d b/ld/testsuite/ld-x86-64/pr27491-2.d
new file mode 100644
index 0000000..753ebb6
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-2.d
@@ -0,0 +1,23 @@
+#as: --64
+#ld: --gc-sections -melf_x86_64 -z start-stop-gc -shared
+#objdump: --syms -dw
+
+.*: +file format elf64-x86-64
+
+
+SYMBOL TABLE:
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __stop_xx
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __start_xx
+#...
+
+
+Disassembly of section .text:
+
+[a-f0-9]+ <foo>:
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__start_xx>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__stop_xx>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <bar1>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <bar2>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-2.s b/ld/testsuite/ld-x86-64/pr27491-2.s
new file mode 100644
index 0000000..a0975ff
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-2.s
@@ -0,0 +1,20 @@
+	.weak __start_xx
+	.weak __stop_xx
+
+	.text
+	.global foo
+foo:
+	movq	__start_xx@gotpcrel(%rip), %rax
+	movq	__stop_xx@gotpcrel(%rip), %rax
+	leaq	bar1(%rip), %rax
+	leaq	bar2(%rip), %rax
+
+	.section xx,"a",unique,0
+	.byte 0
+bar1:
+	.byte 0
+bar2:
+	.byte 0
+
+	.section xx,"a",unique,1
+	.byte 1
diff --git a/ld/testsuite/ld-x86-64/pr27491-3.d b/ld/testsuite/ld-x86-64/pr27491-3.d
new file mode 100644
index 0000000..6dda542
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-3.d
@@ -0,0 +1,21 @@
+#as: --64
+#ld: --gc-sections -melf_x86_64 -z start-stop-gc -shared
+#objdump: --syms -dw
+
+.*: +file format elf64-x86-64
+
+
+SYMBOL TABLE:
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __stop_xx
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __start_xx
+#...
+
+
+Disassembly of section .text:
+
+[a-f0-9]+ <foo>:
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__start_xx>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__stop_xx>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-3.s b/ld/testsuite/ld-x86-64/pr27491-3.s
new file mode 100644
index 0000000..efdcba4
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-3.s
@@ -0,0 +1,14 @@
+	.weak __start_xx
+	.weak __stop_xx
+
+	.text
+	.global foo
+foo:
+	movq	__start_xx@gotpcrel(%rip), %rax
+	movq	__stop_xx@gotpcrel(%rip), %rax
+
+	.section xx,"a",unique,1
+	.byte 0
+
+	.section xx,"aR",unique,0
+	.byte 1
diff --git a/ld/testsuite/ld-x86-64/pr27491-4.d b/ld/testsuite/ld-x86-64/pr27491-4.d
new file mode 100644
index 0000000..54542fd
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-4.d
@@ -0,0 +1,23 @@
+#source: pr27491-4a.s
+#source: pr27491-4b.s
+#as: --64
+#ld: --gc-sections -melf_x86_64 -z start-stop-gc -shared
+#objdump: --syms -dw
+
+.*: +file format elf64-x86-64
+
+
+SYMBOL TABLE:
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __stop_xx
+#...
+[a-f0-9]+ g       xx	[a-f0-9]+ \.protected __start_xx
+#...
+
+
+Disassembly of section .text:
+
+[a-f0-9]+ <foo>:
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__start_xx>
+ +[a-f0-9]+:	48 8d 05 ([0-9a-f]{2} ){4}[ \t]+lea +0x[a-f0-9]+\(%rip\),%rax[ \t]+# [a-f0-9]+ <__stop_xx>
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr27491-4a.s b/ld/testsuite/ld-x86-64/pr27491-4a.s
new file mode 100644
index 0000000..3b17a81
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-4a.s
@@ -0,0 +1,11 @@
+	.weak __start_xx
+	.weak __stop_xx
+
+	.text
+	.global foo
+foo:
+	movq	__start_xx@gotpcrel(%rip), %rax
+	movq	__stop_xx@gotpcrel(%rip), %rax
+
+	.section xx,"a",unique,1
+	.byte 0
diff --git a/ld/testsuite/ld-x86-64/pr27491-4b.s b/ld/testsuite/ld-x86-64/pr27491-4b.s
new file mode 100644
index 0000000..2b46b21
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr27491-4b.s
@@ -0,0 +1,2 @@
+	.section xx,"aR",unique,0
+	.byte 1
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 064438a..ba065c0 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -480,6 +480,12 @@ run_dump_test "property-x86-isa3-x32"
 run_dump_test "property-x86-isa4"
 run_dump_test "property-x86-isa4-x32"
 run_dump_test "code16"
+run_dump_test "pr27491-1a"
+run_dump_test "pr27491-1b"
+run_dump_test "pr27491-1c"
+run_dump_test "pr27491-2"
+run_dump_test "pr27491-3"
+run_dump_test "pr27491-4"
 
 if ![istarget "x86_64-*-linux*"] {
     return