aix: implement TLS relocation for gas and ld

Add support for TLS in XCOFF. Amongst the things done by this commit:
 - Update XCOFF auxialiary header to match new version and allow TLS
   sections.
 - Add TLS sections (.tdata and .tbss) support in gas and ld.
 - Add support for the TLS relocations in gas and ld.
   Two different types BFD_RELOC are created for PPC and PPC64 as
   the size is a pointer, thus distinct in 32 or 64bit.

The addresses given by ld to .tdata and .tbss is a bit special. In
XCOFF, these addresses are actually offsets from the TLS pointer
computed at runtime. AIX assembly and linker does the same. In
top of that, the .tdata must be before .data (this is mandatory for AIX
loader). Thus, the aix ld script is recomputing "." before .data to restore
its original value. There might be a simpler way, but this one is working.

Optimisation linked to TLS relocations aren't yet implemented.

bfd/
	* reloc.c (BFD_RELOC_PPC_TLS_LE, BFD_RELOC_PPC_TLS_IE,
	BFD_RELOC_PPC_TLS_M, BFD_RELOC_PPC_TLS_ML, BFD_RELOC_PPC64_TLS_GD,
	BFD_RELOC_PPC64_TLS_LD, BFD_RELOC_PPC64_TLS_LE,
	BFD_RELOC_PPC64_TLS_IE, BFD_RELOC_PPC64_TLS_M,
	BFD_RELOC_PPC64_TLS_ML): New relocations.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.
	* coff-rs6000.c (xcoff_calculate_relocation): Call
	xcoff_reloc_type_tls for TLS relocations.
	(xcoff_howto_table): Implement TLS relocations.
	(_bfd_xcoff_reloc_type_lookup): Add cases TLS relocations.
	(xcoff_reloc_type_tls): New function.
	* coff64-rs6000.c (xcoff_calculate_relocation): Likewise.
	(xcoff_howto_table): Likewise.
	(_bfd_xcoff_reloc_type_lookup): Likewise.
	* coffcode.h (sec_to_styp_flags): Handle TLS sections.
	(styp_to_sec_flags): Likewise.
	(coff_compute_section_file_positions): Avoid file offset
	optimisation for .data when the previous section is .tdata.
	(coff_write_object_contents): Handle TLS sections.
	* coffswap.h (coff_swap_aouthdr_out): Add support for
	new fields in aouthdr.
	* libxcoff.h (xcoff_reloc_type_tls): Add prototype.
	* xcofflink.c (xcoff_link_add_symbols): Handle XMC_UL.
	(xcoff_need_ldrel_p): Add cases for TLS relocations.
	(xcoff_create_ldrel): Add l_symndx for TLS sections.
gas/
	* config/tc-ppc.c (ppc_xcoff_text_section, ppc_xcoff_data_section,
	(ppc_xcoff_bss_section, ppc_xcoff_tdata_section,
	(ppc_xcoff_tbss_section): New variables.
	(ppc_text_subsegment, ppc_text_csects, ppc_data_subgments,
	(ppc_data_csects): Removed.
	(ppc_xcoff_section_is_initialized, ppc_init_xcoff_section,
	ppc_xcoff_parse_cons): New functions.
	(md_being): Initialize XCOFF sections.
	(ppc_xcoff_suffix): Add support for TLS relocations
	(fixup_size, md_apply_fix): Add support for new BFD_RELOC.
	(ppc_change_csect): Handle XMC_TL, XMC_UL.  Correctly, add XMC_BS
	to .bss section.  Handle new XCOFF section variables.
	(ppc_comm): Likewise.
	(ppc_toc): Likewise.
	(ppc_symbol_new_hook): Likewise.
	(ppc_frob_symbol): Likewise.
	(ppc_fix_adjustable): Add tbss support.
	* config/tc-ppc.h (TC_PARSE_CONS_EXPRESSION): New define.
	(ppc_xcoff_parse_cons): Add prototype.
	(struct ppc_xcoff_section): New structure.
ld/
	* emultempl/aix.em: Ensure .tdata section is removed
	if empty, even with -r flag.
	* scripttempl/aix.sc: Handle TLS sections.
	* testsuite/ld-powerpc/aix52.exp: Add new tests.
	* testsuite/ld-powerpc/aix-tls-reloc-32.d: New test.
	* testsuite/ld-powerpc/aix-tls-reloc-64.d: New test.
	* testsuite/ld-powerpc/aix-tls-reloc.ex: New test.
	* testsuite/ld-powerpc/aix-tls-reloc.s: New test.
	* testsuite/ld-powerpc/aix-tls-section-32.d: New test.
	* testsuite/ld-powerpc/aix-tls-section-64.d: New test.
	* testsuite/ld-powerpc/aix-tls-section.ex: New test.
	* testsuite/ld-powerpc/aix-tls-section.s: New test.
include/
	* coff/internal.h (struct internal_aouthdr): Add new fields.
	* coff/rs6000.h (AOUTHDRÃ): Add new fields.
	* coff/rs6k64.h (struct external_filehdr): Likewise.
	* coff/xcoff.h (_TDATA), _TBSS): New defines
	(RS6K_AOUTHDR_TLS_LE, RS6K_AOUTHDR_RAS, RS6K_AOUTHDR_ALGNTDATA,
	RS6K_AOUTHDR_SHR_SYMTAB, RS6K_AOUTHDR_FORK_POLICY,
	RS6K_AOUTHDR_FORK_COR): New defines.
	(XMC_TU): Removed.
	(XMC_UL): New define.

12 files changed, 264 insertions, 1 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 024ea0d..35c5e20 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,20 @@
 2021-03-12  Clément Chigot  <clement.chigot@atos.net>
 
+	* emultempl/aix.em: Ensure .tdata section is removed
+	if empty, even with -r flag.
+	* scripttempl/aix.sc: Handle TLS sections.
+	* testsuite/ld-powerpc/aix52.exp: Add new tests.
+	* testsuite/ld-powerpc/aix-tls-reloc-32.d: New test.
+	* testsuite/ld-powerpc/aix-tls-reloc-64.d: New test.
+	* testsuite/ld-powerpc/aix-tls-reloc.ex: New test.
+	* testsuite/ld-powerpc/aix-tls-reloc.s: New test.
+	* testsuite/ld-powerpc/aix-tls-section-32.d: New test.
+	* testsuite/ld-powerpc/aix-tls-section-64.d: New test.
+	* testsuite/ld-powerpc/aix-tls-section.ex: New test.
+	* testsuite/ld-powerpc/aix-tls-section.s: New test.
+
+2021-03-12  Clément Chigot  <clement.chigot@atos.net>
+
 	* scripttempl/aix.sc: Add .te to .data section.
 	* testsuite/ld-powerpc/aix52.exp: Add test structure for AIX7+.
 	Add aix-largetoc-1 test.
diff --git a/ld/emultempl/aix.em b/ld/emultempl/aix.em
index d578b6e..e098f2a 100644
--- a/ld/emultempl/aix.em
+++ b/ld/emultempl/aix.em
@@ -969,6 +969,44 @@ gld${EMULATION_NAME}_before_allocation (void)
 	  sec->flags |= SEC_KEEP;
       }
 
+  /* Make sure .tdata is removed if empty, even with -r flag.
+     .tdata is always being generated because its size is needed
+     to cumpute .data address.  */
+  if (bfd_link_relocatable (&link_info))
+    {
+      static const char *const thread_sections[] = {
+	".tdata",
+	".tbss"
+      };
+
+      /* Run lang_size_sections (if not already done).  */
+      if (expld.phase != lang_mark_phase_enum)
+	{
+	  expld.phase = lang_mark_phase_enum;
+	  expld.dataseg.phase = exp_seg_none;
+	  one_lang_size_sections_pass (NULL, FALSE);
+	  lang_reset_memory_regions ();
+	}
+
+      for (i = 0; i < ARRAY_SIZE (thread_sections); i++)
+	{
+	  asection *sec;
+
+	  sec = bfd_get_section_by_name (link_info.output_bfd,
+					 thread_sections[i]);
+
+	  if (sec != NULL && sec->rawsize == 0
+	      && (sec->flags & SEC_KEEP) == 0
+	      && !bfd_section_removed_from_list (link_info.output_bfd,
+						 sec))
+	    {
+	      sec->flags |= SEC_EXCLUDE;
+	      bfd_section_list_remove (link_info.output_bfd, sec);
+	      link_info.output_bfd->section_count--;
+	    }
+	}
+    }
+
   before_allocation_default ();
 }
 
diff --git a/ld/scripttempl/aix.sc b/ld/scripttempl/aix.sc
index aa129d9..3e4d7c0 100644
--- a/ld/scripttempl/aix.sc
+++ b/ld/scripttempl/aix.sc
@@ -37,7 +37,35 @@ SECTIONS
     ${RELOCATING+PROVIDE (_etext = .);}
   }
 
-  . = ALIGN (ALIGN (0x10000000) + (. & 0xfff), 32);
+  /* .tdata and .tbss addresses are representing the offset from
+     the TLS pointer. It starts at -0x7800 for 64bit and -0x7c00
+     for 32bit.
+     TODO: 32bit should have -0x7c00 but it works like this for
+     now.
+     The other particularity is that they must be before .data
+     sections. But .data must be aligned correctly as if the
+     addresses were contiguous. This means that the correct
+     address must be restored, taking into account: the size of
+     .text, its alignment 2^5, the size of .tdata and its
+     aligment 2^4.  */
+  .tdata -0x7800 : {
+    *(.tdata)
+    *(.tl)
+  }
+
+  .tbss : {
+    *(.tbss)
+    *(.ul)
+  }
+
+  . = ${RELOCATING+(ALIGN (0x10000000 + SIZEOF_HEADERS, 32)) + }SIZEOF(.text);
+  . = ALIGN (.,32);
+  . = . + SIZEOF(.tdata);
+  . = ALIGN (.,16);
+
+  /* .data starting address must be in a different segment than
+     the .text addresses. Thus, 0x10000000 is added.  */
+  . = ALIGN (0x10000000) + (. & 0xfff);
   .data . : {
     ${RELOCATING+PROVIDE (_data = .);}
     *(.data)
diff --git a/ld/testsuite/ld-powerpc/aix-tls-reloc-32.d b/ld/testsuite/ld-powerpc/aix-tls-reloc-32.d
new file mode 100644
index 0000000..5103de5
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-reloc-32.d
@@ -0,0 +1,35 @@
+#source: aix-tls-reloc.s
+#as: -a32
+#ld: -b32 -shared -bE:aix-tls-reloc.ex
+#objdump: -dr
+#target: [is_xcoff_format]
+
+.*
+
+Disassembly of section \.text:
+
+.* <\.foo>:
+.*:	80 82 00 00 	l       r4,0\(r2\)
+.*: R_TOC	gd-.*
+.*:	80 62 00 04 	l       r3,4\(r2\)
+.*: R_TOC	.gd-.*
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__tls_get_addr
+.*:	80 62 00 0c 	l       r3,12\(r2\)
+.*: R_TOC	_\$TLSML-.*
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__tls_get_mod
+.*:	80 82 00 08 	l       r4,8\(r2\)
+.*: R_TOC	ld-.*
+.*:	7c a3 22 14 	cax     r5,r3,r4
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__get_tpointer
+.*:	80 82 00 10 	l       r4,16\(r2\)
+.*: R_TOC	ie-.*
+.*:	7c a3 22 14 	cax     r5,r3,r4
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__get_tpointer
+.*:	80 82 00 14 	l       r4,20\(r2\)
+.*: R_TOC	le-.*
+.*:	7c a3 22 14 	cax     r5,r3,r4
+.*
diff --git a/ld/testsuite/ld-powerpc/aix-tls-reloc-64.d b/ld/testsuite/ld-powerpc/aix-tls-reloc-64.d
new file mode 100644
index 0000000..71f6302
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-reloc-64.d
@@ -0,0 +1,31 @@
+#source: aix-tls-reloc.s
+#as: -a32
+#ld: -b32 -shared -bE:aix-tls-reloc.ex
+#objdump: -dr
+#target: [is_xcoff_format]
+
+.*
+
+Disassembly of section \.text:
+
+.* <\.foo>:
+.*:	e8 82 00 00 	ld      r4,0\(r2\)
+.*: R_TOC	gd-.*
+.*:	e8 62 00 08 	ld      r3,8\(r2\)
+.*: R_TOC	.gd-.*
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__tls_get_addr
+.*:	e8 62 00 18 	ld      r3,24\(r2\)
+.*: R_TOC	_\$TLSML-.*
+.*:	48 00 00 03 	bla     0 <\.foo-.*>
+.*: R_BA_26	__tls_get_mod
+.*:	80 82 00 10 	lwz     r4,16\(r2\)
+.*: R_TOC	ld-.*
+.*:	7c a3 22 14 	add     r5,r3,r4
+.*:	e8 82 00 20 	ld      r4,32\(r2\)
+.*: R_TOC	ie-.*
+.*:	7c a4 6a 14 	add     r5,r4,r13
+.*:	e8 82 00 28 	ld      r4,40\(r2\)
+.*: R_TOC	le-.*
+.*:	7c a3 6a 14 	add     r5,r3,r13
+.*
diff --git a/ld/testsuite/ld-powerpc/aix-tls-reloc.ex b/ld/testsuite/ld-powerpc/aix-tls-reloc.ex
new file mode 100644
index 0000000..257cc56
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-reloc.ex
@@ -0,0 +1 @@
+foo
diff --git a/ld/testsuite/ld-powerpc/aix-tls-reloc.s b/ld/testsuite/ld-powerpc/aix-tls-reloc.s
new file mode 100644
index 0000000..62ef73c
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-reloc.s
@@ -0,0 +1,65 @@
+  .globl bar[TL]
+  .csect bar[TL]
+  .long 1
+
+  .toc
+  .tc gd[TC],bar[TL]
+  .tc .gd[TC],bar[TL]@m
+  .tc ld[TC],bar[TL]@ld
+  .tc mh[TC],mh[TC]@ml
+  .tc ie[TC],bar[TL]@ie
+  .tc le[TC],bar[TL]@le
+
+  .globl foo
+  .globl .foo
+  .csect foo[DS],3
+foo:
+  .if size == 32
+  .long	.foo, TOC[tc0], 0
+  .else
+  .llong .foo, TOC[tc0], 0
+  .endif
+
+  .csect foo[PR]
+.foo:
+  #GD
+  .if size == 32
+  lwz 4, gd[TC](2)
+  lwz 3, .gd[TC](2)
+  .else
+  ld 4, gd[TC](2)
+  ld 3, .gd[TC](2)
+  .endif
+  bla __tls_get_addr
+
+  #LD
+  .if size == 32
+  lwz 3, mh[TC](2)
+  .else
+  ld 3, mh[TC](2)
+  .endif
+  bla __tls_get_mod
+  lwz 4, ld[TC](2)
+  add 5,3,4
+
+  #IE
+  .if size == 32
+  bla __get_tpointer
+  lwz 4, ie[TC](2)
+  add 5,3,4
+  .else
+  ld 4, ie[TC](2)
+  add 5,4,13
+  .endif
+
+  #LE
+  .if size == 32
+  bla __get_tpointer
+  lwz 4, le[TC](2)
+  add 5,3,4
+  .else
+  ld 4, le[TC](2)
+  add 5,3,13
+  .endif
+
+.rename mh[TC], "_$TLSML" # Symbol for the module handle
diff --git a/ld/testsuite/ld-powerpc/aix-tls-section-32.d b/ld/testsuite/ld-powerpc/aix-tls-section-32.d
new file mode 100644
index 0000000..16b9686
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-section-32.d
@@ -0,0 +1,15 @@
+#source: aix-tls-section.s
+#as: -a32
+#ld: -b32 -shared -bE:aix-tls-section.ex
+#objdump: -hw
+#target: [is_xcoff_format]
+
+.*
+
+Sections:
+.*
+  0 \.text         .*  .*  .*  .*  .*  ALLOC, LOAD, CODE
+  1 \.tdata        00000008  ffff8800  ffff8800  .*  .*  CONTENTS, ALLOC, LOAD, DATA, THREAD_LOCAL
+  2 \.tbss         00000008  ffff8808  ffff8808  .*  .*  ALLOC, THREAD_LOCAL
+  3 \.data         .*  .*  .*  .*  .*  ALLOC, LOAD, DATA
+#...
diff --git a/ld/testsuite/ld-powerpc/aix-tls-section-64.d b/ld/testsuite/ld-powerpc/aix-tls-section-64.d
new file mode 100644
index 0000000..dceeaaf
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-section-64.d
@@ -0,0 +1,15 @@
+#source: aix-tls-section.s
+#as: -a64
+#ld: -b64 -shared -bE:aix-tls-section.ex
+#objdump: -hw
+#target: [is_xcoff_format]
+
+.*
+
+Sections\:
+.*
+  0 \.text         .*  .*  .*  .*  .*  ALLOC, LOAD, CODE
+  1 \.tdata        00000008  ffffffffffff8800  ffffffffffff8800  .*  .*  CONTENTS, ALLOC, LOAD, DATA, THREAD_LOCAL
+  2 \.tbss         00000008  ffffffffffff8808  ffffffffffff8808  .*  .*  ALLOC, THREAD_LOCAL
+  3 \.data         .* .* .*  .*  .*  ALLOC, LOAD, DATA
+#...
diff --git a/ld/testsuite/ld-powerpc/aix-tls-section.ex b/ld/testsuite/ld-powerpc/aix-tls-section.ex
new file mode 100644
index 0000000..3bd1f0e
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-section.ex
@@ -0,0 +1,2 @@
+foo
+bar
diff --git a/ld/testsuite/ld-powerpc/aix-tls-section.s b/ld/testsuite/ld-powerpc/aix-tls-section.s
new file mode 100644
index 0000000..30c328f
--- /dev/null
+++ b/ld/testsuite/ld-powerpc/aix-tls-section.s
@@ -0,0 +1,8 @@
+  /* .tbss */
+  .comm foo[UL],8
+  .lcomm foo2_l,8,foo2[UL]
+
+  /* .tdata */
+  .globl bar[TL]
+  .csect bar[TL]
+  .long 1
diff --git a/ld/testsuite/ld-powerpc/aix52.exp b/ld/testsuite/ld-powerpc/aix52.exp
index 3dfbae0..0e68b6a 100644
--- a/ld/testsuite/ld-powerpc/aix52.exp
+++ b/ld/testsuite/ld-powerpc/aix52.exp
@@ -275,6 +275,16 @@ set aix7tests {
 	"" {aix-largetoc-1.s}
 	{{objdump -dr aix-largetoc-1-SIZE.d}}
 	"aix-largetoc-1.so"}
+
+    {"TLS relocations" "-shared -bE:aix-tls-reloc.ex"
+	"" {aix-tls-reloc.s}
+	{{objdump -dr aix-tls-reloc-SIZE.d}}
+	"aix-tls-reloc.so"}
+
+    {"TLS section" "-shared -bE:aix-tls-section.ex"
+	"" {aix-tls-section.s}
+	{{objdump -hw aix-tls-section-SIZE.d}}
+	"aix-tls-section.so"}
 }
 
 foreach test $aix7tests {