gold: Support 386 TLS code sequences without PLT

There are extensions to 386 psABI:

https://groups.google.com/forum/#!topic/ia32-abi/awsRSvJOJfs

to call tls_get_addr via GOT:

call *___tls_get_addr@GOT(%reg)

where EBX register isn't required as GOT base.

Since direct call is 4-byte long and indirect call, is 5-byte long, the
extra one byte must be handled properly.

For general dynamic model, 7-byte lea instruction before call
instruction is replaced by 6-byte one to make room for indirect call.
For local dynamic model, we simply use 5-byte indirect call.

TLS linker optimization is updated to recognize new instruction
patterns.  For local dynamic model to local exec model transition,
we generate a 6-byte lea instruction as nop, instead of a 1-byte nop
plus a 4-byte lea instruction.

	PR gold/20308
	* i386.cc (Target_i386::Relocate::relocate): Allow
	R_386_GOT32X relocation against ___tls_get_addr.
	(Target_i386::Relocate::tls_gd_to_ie): Support indirect
	call to __tls_get_addr.
	(Target_i386::Relocate::tls_gd_to_le): Likewise.
	(Target_i386::Relocate::tls_ld_to_le): Likewise.
	* testsuite/Makefile.am (check_PROGRAMS): Add pr20308a_test,
	pr20308b_test, pr20308c_test, pr20308d_test, pr20308e_test.
	(pr20308a_test_SOURCES): New.
	(pr20308a_test_DEPENDENCIES): Likewise.
	(pr20308a_test_CFLAGS): Likewise.
	(pr20308a_test_LDFLAGS): Likewise.
	(pr20308a_test_LDADD): Likewise.
	(pr20308b_test_SOURCES): Likewise.
	(pr20308b_test_DEPENDENCIES): Likewise.
	(pr20308b_test_CFLAGS): Likewise.
	(pr20308b_test_LDFLAGS): Likewise.
	(pr20308b_test_LDADD): Likewise.
	(pr20308c_test_SOURCES): Likewise.
	(pr20308c_test_DEPENDENCIES): Likewise.
	(pr20308c_test_CFLAGS): Likewise.
	(pr20308c_test_LDFLAGS): Likewise.
	(pr20308c_test_LDADD): Likewise.
	(pr20308d_test_SOURCES): Likewise.
	(pr20308d_test_DEPENDENCIES): Likewise.
	(pr20308d_test_CFLAGS): Likewise.
	(pr20308d_test_LDFLAGS): Likewise.
	(pr20308d_test_LDADD): Likewise.
	(pr20308e_test_SOURCES): Likewise.
	(pr20308e_test_DEPENDENCIES): Likewise.
	(pr20308e_test_CFLAGS): Likewise.
	(pr20308e_test_LDFLAGS): Likewise.
	(pr20308e_test_LDADD): Likewise.
	(pr20308a.so): Likewise.
	(pr20308b.so): Likewise.
	(pr20308_gd.o): Likewise.
	(pr20308_ld.o): Likewise.
	(MOSTLYCLEANFILES): Add pr20308a.so pr20308b.so.
	* testsuite/Makefile.in: Regenerated.
	* testsuite/pr20308_def.c: New file.
	* testsuite/pr20308_gd.S: Likewise.
	* testsuite/pr20308_ld.S: Likewise.
	* testsuite/pr20308_main.c: Likewise.

1 files changed, 71 insertions, 0 deletions

diff --git a/gold/testsuite/pr20308_ld.S b/gold/testsuite/pr20308_ld.S
new file mode 100644
index 0000000..f1295cf
--- /dev/null
+++ b/gold/testsuite/pr20308_ld.S
@@ -0,0 +1,71 @@
+	.text
+	.p2align 4,,15
+	.globl	get_ld
+	.type	get_ld, @function
+get_ld:
+	pushl	%ebx
+	call	__x86.get_pc_thunk.bx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
+	subl	$8, %esp
+	leal	ld@tlsldm(%ebx), %eax
+	call	___tls_get_addr@PLT
+	leal	ld@dtpoff(%eax), %eax
+	addl	$8, %esp
+	popl	%ebx
+	ret
+	.size	get_ld, .-get_ld
+	.p2align 4,,15
+	.globl	set_ld
+	.type	set_ld, @function
+set_ld:
+	pushl	%ebx
+	call	__x86.get_pc_thunk.bx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
+	subl	$8, %esp
+	leal	ld@tlsldm(%ebx), %eax
+	call	___tls_get_addr@PLT
+	movl	16(%esp), %edx
+	leal	ld@dtpoff(%eax), %eax
+	movl	%edx, (%eax)
+	addl	$8, %esp
+	popl	%ebx
+	ret
+	.size	set_ld, .-set_ld
+	.p2align 4,,15
+	.globl	test_ld
+	.type	test_ld, @function
+test_ld:
+	call	__x86.get_pc_thunk.cx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ecx
+	subl	$12, %esp
+	leal	ld@tlsldm(%ecx), %eax
+	call	*___tls_get_addr@GOT(%ecx)
+	movl	16(%esp), %ecx
+	leal	ld@dtpoff(%eax), %eax
+	cmpl	%ecx, (%eax)
+	sete	%al
+	addl	$12, %esp
+	movzbl	%al, %eax
+	ret
+	.size	test_ld, .-test_ld
+	.section	.tbss,"awT",@nobits
+	.align 4
+	.type	ld, @object
+	.size	ld, 4
+ld:
+	.zero	4
+	.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
+	.section	.text.__x86.get_pc_thunk.cx,"axG",@progbits,__x86.get_pc_thunk.cx,comdat
+	.globl	__x86.get_pc_thunk.cx
+	.hidden	__x86.get_pc_thunk.cx
+	.type	__x86.get_pc_thunk.cx, @function
+__x86.get_pc_thunk.cx:
+	movl	(%esp), %ecx
+	ret
+	.section	.note.GNU-stack,"",@progbits