See https://sourceware.org/ml/binutils/2016-07/msg00091.html
This patch stop --gc-sections elf_gc_sweep_symbol localizing symbols
that ought to remain global.
The difficulty with always descending into output section statements
is that symbols defined by the script in such statements don't have
a bfd section when lang_do_assignments runs early in the link process.
There are two approaches to curing this problem. Either we can
create the bfd section early, or we can use a special section. This
patch takes the latter approach and uses bfd_und_section. (Creating
bfd sections early results in changed output section order, and thus
lots of testsuite failures. You can't create all output sections
early to ensure proper ordering as KEEP then stops empty sections
from being stripped.)
The wrinkle with this approach is that some code that runs at
gc-sections time needs to be made aware of the odd defined symbols
using bfd_und_section.
bfd/
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Handle symbols
defined temporarily with bfd_und_section.
* elflink.c (_bfd_elf_gc_keep): Don't set SEC_KEEP for bfd_und_section.
* elfxx-mips.c (mips_elf_local_pic_function_p): Exclude defined
symbols with bfd_und_section.
ld/
* ldlang.c (lang_do_assignments_1): Descend into output section
statements that do not yet have bfd sections. Set symbol section
temporarily for symbols defined in such statements to the undefined
section. Don't error on data or reloc statements until final phase.
* ldexp.c (exp_fold_tree_1 <etree_assign>): Handle bfd_und_section
in expld.section.
* testsuite/ld-mmix/bpo-10.d: Adjust.
* testsuite/ld-mmix/bpo-11.d: Adjust.
For the case where a function which requires an LA25 stub is at the
beginning of a section we use a short sequence comprised of a LUI/ADDIU
instruction pair only and prepended to the associated function rather
than using a trailing jump to reach the function. This works by
checking for the offset into section of the function symbol being 0.
This is however never the case for microMIPS function symbols, which
have the ISA bit set. Consequently the short LA25 sequence is never
produced for microMIPS functions, like with the following example:
$ cat la25a.s
.abicalls
.global f1
.ent f1
f1:
.set noreorder
.cpload $25
.set reorder
.option pic0
jal f2
.option pic2
jr $31
.end f1
.global f2
.ent f2
f2:
jr $31
.end f2
$ cat la25b.s
.abicalls
.option pic0
.global __start
.ent __start
__start:
jal f1
jal f2
.end __start
$ as -mmicromips -32 -EB -o la25a.o la25a.s
$ as -mmicromips -32 -EB -o la25b.o la25b.s
$ ld -melf32btsmip -o la25 la25a.o la25b.o
$ objdump -d la25
la25: file format elf32-tradbigmips
Disassembly of section .text:
004000d0 <.pic.f2>:
4000d0: 41b9 0040 lui t9,0x40
4000d4: d420 0083 j 400106 <f2>
4000d8: 3339 0107 addiu t9,t9,263
4000dc: 0000 0000 nop
004000e0 <.pic.f1>:
4000e0: 41b9 0040 lui t9,0x40
4000e4: d420 0078 j 4000f0 <f1>
4000e8: 3339 00f1 addiu t9,t9,241
4000ec: 0000 0000 nop
004000f0 <f1>:
4000f0: 41bc 0002 lui gp,0x2
4000f4: 339c 801f addiu gp,gp,-32737
4000f8: 033c e150 addu gp,gp,t9
4000fc: f420 0083 jal 400106 <f2>
400100: 0000 0000 nop
400104: 45bf jrc ra
00400106 <f2>:
400106: 45bf jrc ra
...
00400110 <__start>:
400110: f420 0070 jal 4000e0 <.pic.f1>
400114: 0000 0000 nop
400118: f420 0068 jal 4000d0 <.pic.f2>
40011c: 0000 0000 nop
$
where `.pic.f1' could omit the trailing jump and the filler NOP and just
fall through to `f1'.
Correct the problem by masking out the ISA bit from microMIPS functions,
which fixes the earlier example:
$ objdump -d la25
la25: file format elf32-tradbigmips
Disassembly of section .text:
004000d0 <.pic.f2>:
4000d0: 41b9 0040 lui t9,0x40
4000d4: d420 0083 j 400106 <f2>
4000d8: 3339 0107 addiu t9,t9,263
...
004000e8 <.pic.f1>:
4000e8: 41b9 0040 lui t9,0x40
4000ec: 3339 00f1 addiu t9,t9,241
004000f0 <f1>:
4000f0: 41bc 0002 lui gp,0x2
4000f4: 339c 801f addiu gp,gp,-32737
4000f8: 033c e150 addu gp,gp,t9
4000fc: f420 0083 jal 400106 <f2>
400100: 0000 0000 nop
400104: 45bf jrc ra
00400106 <f2>:
400106: 45bf jrc ra
...
00400110 <__start>:
400110: f420 0074 jal 4000e8 <.pic.f1>
400114: 0000 0000 nop
400118: f420 0068 jal 4000d0 <.pic.f2>
40011c: 0000 0000 nop
$
There is no need to do anything for MIPS16 functions, because if any
LA25 stub has been generated for such a function, then it is only
required for an associated call thunk only, which is regular MIPS code
and the address of which, with the ISA bit clear, is returned by
`mips_elf_get_la25_target'.
This problem has been there since the beginning of microMIPS support:
commit df58fc944d
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date: Sun Jul 24 14:20:15 2011 +0000
<https://sourceware.org/ml/binutils/2011-07/msg00198.html>, ("MIPS:
microMIPS ASE support").
bfd/
* elfxx-mips.c (mips_elf_add_la25_stub): Clear the ISA bit of
the stub address retrieved if associated with a microMIPS
function.
Fix a problem with missing microMIPS symbol annotation with microMIPS
LA25 stub symbols. The consequence of the issue is these symbols appear
in the symbol table as regular MIPS symbols with the ISA bit set, as
shown with the example below:
$ cat la25a.s
.abicalls
.global f1
.ent f1
f1:
.set noreorder
.cpload $25
.set reorder
.option pic0
jal f2
.option pic2
jr $31
.end f1
.global f2
.ent f2
f2:
jr $31
.end f2
$ cat la25b.s
.abicalls
.option pic0
.global __start
.ent __start
__start:
jal f1
jal f2
.end __start
$ as -mmicromips -32 -EB -o la25a.o la25a.s
$ as -mmicromips -32 -EB -o la25b.o la25b.s
$ ld -melf32btsmip -o la25 la25a.o la25b.o
$ readelf -s la25
Symbol table '.symtab' contains 18 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00400098 0 SECTION LOCAL DEFAULT 1
2: 004000b0 0 SECTION LOCAL DEFAULT 2
3: 004000d0 0 SECTION LOCAL DEFAULT 3
4: 00000000 0 SECTION LOCAL DEFAULT 4
5: 00000000 0 SECTION LOCAL DEFAULT 5
6: 00418110 0 NOTYPE LOCAL DEFAULT 3 _gp
7: 004000e1 16 FUNC LOCAL DEFAULT 3 .pic.f1
8: 004000d1 16 FUNC LOCAL DEFAULT 3 .pic.f2
9: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _fdata
10: 00400110 16 FUNC GLOBAL DEFAULT [MICROMIPS] 3 __start
11: 00400106 2 FUNC GLOBAL DEFAULT [MICROMIPS] 3 f2
12: 004000d0 0 NOTYPE GLOBAL DEFAULT 3 _ftext
13: 00410120 0 NOTYPE GLOBAL DEFAULT 3 __bss_start
14: 004000f0 22 FUNC GLOBAL DEFAULT [MICROMIPS] 3 f1
15: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _edata
16: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _end
17: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _fbss
$
where microMIPS annotation is missing for `.pic.f1' and `.pic.f2' even
though these stubs are associated with microMIPS functions `f1' and `f2'
respectively.
Add the missing annotation then, by copying it from the function symbol
an LA25 stub is associated with, correcting the example above:
$ readelf -s la25
Symbol table '.symtab' contains 18 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00400098 0 SECTION LOCAL DEFAULT 1
2: 004000b0 0 SECTION LOCAL DEFAULT 2
3: 004000d0 0 SECTION LOCAL DEFAULT 3
4: 00000000 0 SECTION LOCAL DEFAULT 4
5: 00000000 0 SECTION LOCAL DEFAULT 5
6: 00418110 0 NOTYPE LOCAL DEFAULT 3 _gp
7: 004000e0 16 FUNC LOCAL DEFAULT [MICROMIPS] 3 .pic.f1
8: 004000d0 16 FUNC LOCAL DEFAULT [MICROMIPS] 3 .pic.f2
9: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _fdata
10: 00400110 16 FUNC GLOBAL DEFAULT [MICROMIPS] 3 __start
11: 00400106 2 FUNC GLOBAL DEFAULT [MICROMIPS] 3 f2
12: 004000d0 0 NOTYPE GLOBAL DEFAULT 3 _ftext
13: 00410120 0 NOTYPE GLOBAL DEFAULT 3 __bss_start
14: 004000f0 22 FUNC GLOBAL DEFAULT [MICROMIPS] 3 f1
15: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _edata
16: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _end
17: 00410120 0 NOTYPE GLOBAL DEFAULT 3 _fbss
$
This problem has been there since the beginning of microMIPS support:
commit df58fc944d
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date: Sun Jul 24 14:20:15 2011 +0000
<https://sourceware.org/ml/binutils/2011-07/msg00198.html>, ("MIPS:
microMIPS ASE support").
bfd/
* elfxx-mips.c (mips_elf_create_stub_symbol): For a microMIPS
stub also add STO_MICROMIPS annotation.
Fix a linker regression introduced with commit 9d862524f6 ("MIPS:
Verify the ISA mode and alignment of branch and jump targets") causing a
build failure in microMIPS glibc where the `zdump' tool fails to link:
.../timezone/zdump.o: In function `yeartot':
.../timezone/zdump.c:758:(.text+0x62): Jump to a non-instruction-aligned address
.../timezone/zdump.c:758:(.text+0x76): Jump to a non-instruction-aligned address
.../timezone/zdump.c:768:(.text+0x112): Jump to a non-instruction-aligned address
.../timezone/zdump.c:774:(.text+0x1b8): Jump to a non-instruction-aligned address
.../timezone/zdump.c:774:(.text+0x1cc): Jump to a non-instruction-aligned address
collect2: error: ld returned 1 exit status
make[2]: *** [.../timezone/zdump] Error 1
The cause of the failure is the stricter check introduced with the said
change for jump and branch targets tripping on the address of microMIPS
LA25 stubs. Despite being microMIPS code these stubs do not have the
ISA bit set throughout the relocation calculation process, because they
have their address set to the memory offset into the stub section they
are placed in.
The `mips_elf_la25_stub' structure does not carry ISA mode information,
but there is no need to extend it, because the ISA mode can be inferred
from the original symbol, which will have STO_MICROMIPS annotation, so
use that instead to set the ISA bit appropriately. Also only LA25 stubs
associated with microMIPS symbols need to have the ISA bit set, because
other LA25 stubs are made with regular MIPS code, even if associated
with a MIPS16 symbol (in which case they are needed by a call thunk only
rather than the MIPS16 function proper).
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation): Set the ISA bit
in microMIPS LA25 stub references.
Complement:
commit 1bbce13264
Author: Maciej W. Rozycki <macro@linux-mips.org>
Date: Mon Jun 24 23:55:46 2013 +0000
<https://sourceware.org/ml/binutils/2013-06/msg00077.html>, ("MIPS:
Compressed PLT/stubs support"), and also choose between regular and
compressed PLT entries as appropriate for any branches referring.
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation): Handle branches
in PLT compression selection.
(_bfd_mips_elf_check_relocs): Likewise.
ld/
* testsuite/ld-mips-elf/compressed-plt-1.s: Add branch support.
* testsuite/ld-mips-elf/compressed-plt-1a.s: Likewise.
* testsuite/ld-mips-elf/compressed-plt-1b.s: Likewise.
* testsuite/ld-mips-elf/compressed-plt-1-o32-branch.od: New
test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-branch.rd: New
test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-mips16-bronly.od:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-mips16-bronly.rd:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-mips16-branch.od:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-mips16-branch.rd:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-umips-bronly.od:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-umips-bronly.rd:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-umips-branch.od:
New test.
* testsuite/ld-mips-elf/compressed-plt-1-o32-umips-branch.rd:
New test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
Convert cross-mode regular MIPS and microMIPS BAL instructions to JALX,
similarly to how JAL instructions are converted.
bfd/
* elfxx-mips.c (mips_elf_perform_relocation): Convert cross-mode
BAL to JALX.
(_bfd_mips_elf_relocate_section) <bfd_reloc_outofrange>: Add a
corresponding error message.
gas/
* config/tc-mips.c (mips_force_relocation, mips_fix_adjustable):
Adjust comments for BAL to JALX linker conversion.
(fix_bad_cross_mode_branch_p): Accept cross-mode BAL.
* testsuite/gas/mips/unaligned-branch-1.l: Update error messages
expected.
* testsuite/gas/mips/unaligned-branch-micromips-1.l: Likewise.
* testsuite/gas/mips/branch-local-4.d: New test.
* testsuite/gas/mips/branch-local-n32-4.d: New test.
* testsuite/gas/mips/branch-local-n64-4.d: New test.
* testsuite/gas/mips/branch-addend.d: New test.
* testsuite/gas/mips/branch-addend-n32.d: New test.
* testsuite/gas/mips/branch-addend-n64.d: New test.
* testsuite/gas/mips/branch-local-4.s: New test source.
* testsuite/gas/mips/branch-addend.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.
ld/
* testsuite/ld-mips-elf/unaligned-branch-2.d: Update error
messages expected.
* testsuite/ld-mips-elf/unaligned-branch-r6-1.d: Likewise.
* testsuite/ld-mips-elf/unaligned-branch-mips16.d: Likewise.
* testsuite/ld-mips-elf/unaligned-branch-micromips.d: Likewise.
* testsuite/ld-mips-elf/bal-jalx-addend.d: New test.
* testsuite/ld-mips-elf/bal-jalx-local.d: New test.
* testsuite/ld-mips-elf/bal-jalx-pic.d: New test.
* testsuite/ld-mips-elf/bal-jalx-addend-n32.d: New test.
* testsuite/ld-mips-elf/bal-jalx-local-n32.d: New test.
* testsuite/ld-mips-elf/bal-jalx-pic-n32.d: New test.
* testsuite/ld-mips-elf/bal-jalx-addend-n64.d: New test.
* testsuite/ld-mips-elf/bal-jalx-local-n64.d: New test.
* testsuite/ld-mips-elf/bal-jalx-pic-n64.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-2.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-3.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-2.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-3.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-2.s: New test source.
* testsuite/ld-mips-elf/unaligned-jalx-3.s: New test source.
* testsuite/ld-mips-elf/unaligned-jalx-addend-2.s: New test
source.
* testsuite/ld-mips-elf/unaligned-jalx-addend-3.s: New test
source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
Verify that the ISA mode of branch targets is the same as the referring
relocation, so that an attempt to produce a branch between instructions
encoded in different ISA modes each causes an error rather than silently
producing non-functional code. Make sure that no symbol or addend bits
are silently truncated: terminate with an error if the relocation value
calculated cannot be encoded in the relocatable field of a branch; for
REL targets also applying to any intermediate addend.
Also make jump target's alignment verification consistent with that for
branches.
This change will require an update to some obscure handcoded assembly
sources which make branches to labels placed at data objects, however
for microMIPS code only. These labels will have to be updated with the
`.insn' directive for containing code to assemble and link successfully.
Such code is broken as any such labels have always been required by the
microMIPS architecture specification[1][2] to be annotated this way for
correct interpretation, and with our old code missing `.insn' directives
caused labels to present different semantics depending on whether they
were referred with branch (ISA bit ignored) or other relocations (ISA
bit respected).
Enforcing these checks however will ensure errors in building software,
like mixed regular MIPS and microMIPS code links with branches between,
will be diagnosed at the build time rather than causing odd run-time
errors such as intermittent crashes. It will also let cross-mode BAL
instructions be converted to JALX instructions, with a separate change.
References:
[1] "MIPS Architecture for Programmers, Volume II-B: The microMIPS32
Instruction Set", MIPS Technologies, Inc., Document Number: MD00582,
Revision 5.04, January 15, 2014, Section 7.1 "Assembly-Level
Compatibility", p. 533
[2] "MIPS Architecture for Programmers, Volume II-B: The microMIPS64
Instruction Set", MIPS Technologies, Inc., Document Number: MD00594,
Revision 5.04, January 15, 2014, Section 8.1 "Assembly-Level
Compatibility", p. 623
bfd/
* elfxx-mips.c (b_reloc_p): Add R_MICROMIPS_PC16_S1,
R_MICROMIPS_PC10_S1 and R_MICROMIPS_PC7_S1.
(branch_reloc_p): New function.
(mips_elf_calculate_relocation): Handle ISA mode determination
for relocations against section symbols, against absolute
symbols and absolute relocations. Also set `*cross_mode_jump_p'
for branches.
<R_MIPS16_26, R_MIPS_26, R_MICROMIPS_26_S1>: Suppress alignment
checks for weak undefined symbols. Also check target alignment
within the same ISA mode.
<R_MIPS_PC16, R_MIPS_GNU_REL16_S2>: Handle cross-mode branches
in the alignment check.
<R_MICROMIPS_PC7_S1>: Add an alignment check.
<R_MICROMIPS_PC10_S1>: Likewise.
<R_MICROMIPS_PC16_S1>: Likewise.
(mips_elf_perform_relocation): Report a failure for unsupported
same-mode JALX instructions and cross-mode branches.
(_bfd_mips_elf_relocate_section) <bfd_reloc_outofrange>: Add
error messages for jumps to misaligned addresses.
gas/
* config/tc-mips.c (mips_force_relocation): Also retain branch
relocations against MIPS16 and microMIPS symbols.
(fix_bad_cross_mode_jump_p): New function.
(fix_bad_same_mode_jalx_p): Likewise.
(fix_bad_misaligned_jump_p): Likewise.
(fix_bad_cross_mode_branch_p): Likewise.
(fix_bad_misaligned_branch_p): Likewise.
(fix_validate_branch): Likewise.
(md_apply_fix) <BFD_RELOC_MIPS_JMP, BFD_RELOC_MIPS16_JMP>
<BFD_RELOC_MICROMIPS_JMP>: Separate from BFD_RELOC_MIPS_SHIFT5,
etc. Verify the ISA mode and alignment of the jump target.
<BFD_RELOC_MIPS_21_PCREL_S2>: Replace the inline alignment check
with a call to `fix_validate_branch'.
<BFD_RELOC_MIPS_26_PCREL_S2>: Likewise.
<BFD_RELOC_16_PCREL_S2>: Likewise.
<BFD_RELOC_MICROMIPS_7_PCREL_S1, BFD_RELOC_MICROMIPS_10_PCREL_S1>
<BFD_RELOC_MICROMIPS_16_PCREL_S1>: Retain the original addend.
Verify the ISA mode and alignment of the branch target.
(md_convert_frag): Verify the ISA mode and alignment of resolved
MIPS16 branch targets.
* testsuite/gas/mips/branch-misc-1.s: Annotate non-instruction
branch targets with `.insn'.
* testsuite/gas/mips/branch-misc-5.s: Likewise.
* testsuite/gas/mips/micromips@branch-misc-5-64.d: Update
accordingly.
* testsuite/gas/mips/micromips@branch-misc-5pic-64.d: Likewise.
* testsuite/gas/mips/micromips-branch-relax.s: Annotate
non-instruction branch target with `.insn'.
* testsuite/gas/mips/micromips.s: Replace microMIPS JALX targets
with external symbols.
* testsuite/gas/mips/micromips-insn32.d: Update accordingly.
* testsuite/gas/mips/micromips-noinsn32.d: Likewise.
* testsuite/gas/mips/micromips-trap.d: Likewise.
* testsuite/gas/mips/micromips.d: Likewise.
* testsuite/gas/mips/mips16.s: Annotate non-instruction branch
targets with `.insn'.
* testsuite/gas/mips/mips16.d: Update accordingly.
* testsuite/gas/mips/mips16-64.d: Likewise.
* testsuite/gas/mips/mips16-dwarf2.s: Annotate non-instruction
branch target with `.insn'.
* testsuite/gas/mips/relax-swap3.s: Likewise.
* testsuite/gas/mips/branch-local-2.l: New list test.
* testsuite/gas/mips/branch-local-3.l: New list test.
* testsuite/gas/mips/branch-local-n32-2.l: New list test.
* testsuite/gas/mips/branch-local-n32-3.l: New list test.
* testsuite/gas/mips/branch-local-n64-2.l: New list test.
* testsuite/gas/mips/branch-local-n64-3.l: New list test.
* testsuite/gas/mips/unaligned-jump-1.l: New list test.
* testsuite/gas/mips/unaligned-jump-2.l: New list test.
* testsuite/gas/mips/unaligned-jump-3.d: New test.
* testsuite/gas/mips/unaligned-jump-mips16-1.l: New list test.
* testsuite/gas/mips/unaligned-jump-mips16-2.l: New list test.
* testsuite/gas/mips/unaligned-jump-mips16-3.d: New test.
* testsuite/gas/mips/unaligned-jump-micromips-1.l: New list
test.
* testsuite/gas/mips/unaligned-jump-micromips-2.l: New list
test.
* testsuite/gas/mips/unaligned-jump-micromips-3.d: New test.
* testsuite/gas/mips/unaligned-branch-1.l: New list test.
* testsuite/gas/mips/unaligned-branch-2.l: New list test.
* testsuite/gas/mips/unaligned-branch-3.d: New test.
* testsuite/gas/mips/unaligned-branch-r6-1.l: New list test.
* testsuite/gas/mips/unaligned-branch-r6-2.l: New list test.
* testsuite/gas/mips/unaligned-branch-r6-3.l: New list test.
* testsuite/gas/mips/unaligned-branch-r6-4.l: New list test.
* testsuite/gas/mips/unaligned-branch-r6-5.d: New test.
* testsuite/gas/mips/unaligned-branch-r6-6.d: New test.
* testsuite/gas/mips/unaligned-branch-mips16-1.l: New list test.
* testsuite/gas/mips/unaligned-branch-mips16-2.l: New list test.
* testsuite/gas/mips/unaligned-branch-mips16-3.d: New test.
* testsuite/gas/mips/unaligned-branch-micromips-1.l: New list
test.
* testsuite/gas/mips/unaligned-branch-micromips-2.l: New list
test.
* testsuite/gas/mips/unaligned-branch-micromips-3.d: New test.
* testsuite/gas/mips/branch-local-2.s: New test source.
* testsuite/gas/mips/branch-local-3.s: New test source.
* testsuite/gas/mips/branch-local-n32-2.s: New test source.
* testsuite/gas/mips/branch-local-n32-3.s: New test source.
* testsuite/gas/mips/branch-local-n64-2.s: New test source.
* testsuite/gas/mips/branch-local-n64-3.s: New test source.
* testsuite/gas/mips/unaligned-jump-1.s: New test source.
* testsuite/gas/mips/unaligned-jump-2.s: New test source.
* testsuite/gas/mips/unaligned-jump-mips16-1.s: New test source.
* testsuite/gas/mips/unaligned-jump-mips16-2.s: New test source.
* testsuite/gas/mips/unaligned-jump-micromips-1.s: New test
source.
* testsuite/gas/mips/unaligned-jump-micromips-2.s: New test
source.
* testsuite/gas/mips/unaligned-branch-1.s: New test source.
* testsuite/gas/mips/unaligned-branch-2.s: New test source.
* testsuite/gas/mips/unaligned-branch-r6-1.s: New test source.
* testsuite/gas/mips/unaligned-branch-r6-2.s: New test source.
* testsuite/gas/mips/unaligned-branch-r6-3.s: New test source.
* testsuite/gas/mips/unaligned-branch-r6-4.s: New test source.
* testsuite/gas/mips/unaligned-branch-mips16-1.s: New test
source.
* testsuite/gas/mips/unaligned-branch-mips16-2.s: New test
source.
* testsuite/gas/mips/unaligned-branch-micromips-1.s: New test
source.
* testsuite/gas/mips/unaligned-branch-micromips-2.s: New test
source.
* testsuite/gas/mips/mips.exp: Run the new tests.
ld/
* testsuite/ld-mips-elf/unaligned-jalx-1.d: Update error message
expected.
* testsuite/ld-mips-elf/unaligned-jalx-addend-1.d: Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-addend-mips16-1.d:
Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-addend-micromips-1.d:
Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-1.d: Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-1.d: Likewise.
* testsuite/ld-mips-elf/undefweak-overflow.s: Add jumps,
microMIPS BAL and MIPS16 instructions.
* testsuite/ld-mips-elf/undefweak-overflow.d: Update
accordingly.
* testsuite/ld-mips-elf/unaligned-branch-2.d: New test.
* testsuite/ld-mips-elf/unaligned-branch-r6-1.d: New test.
* testsuite/ld-mips-elf/unaligned-branch-r6-2.d: New test.
* testsuite/ld-mips-elf/unaligned-branch-mips16.d: New test.
* testsuite/ld-mips-elf/unaligned-branch-micromips.d: New test.
* testsuite/ld-mips-elf/unaligned-jump-mips16.d: New test.
* testsuite/ld-mips-elf/unaligned-jump-micromips.d: New test.
* testsuite/ld-mips-elf/unaligned-jump.d: New test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
As with commit ed53407eec ("MIPS/BFD: Don't stop processing on
`bfd_reloc_outofrange'") don't bail out right away and instead continue
processing on a cross-mode jump conversion error, so that any further
issues are also reported. Adjust message formatting accordingly, using
`%X' to abort processing at conclusion. Remove the full stop from the
end of the message, for consistency across error reporting.
Adjust the corresponding test case accordingly and make it trigger the
error twice.
bfd/
* elfxx-mips.c (mips_elf_perform_relocation): Call
`info->callbacks->einfo' rather than `*_bfd_error_handler' and
use the `%X%H' format for the cross-mode jump conversion error
message. Remove the full stop from the end of the message.
Continue processing rather than returning failure.
ld/
* testsuite/ld-mips-elf/mode-change-error-1a.s: Trigger an error
twice rather than once.
* testsuite/ld-mips-elf/mode-change-error-1.d: Adjust
accordingly. Remove the full stop from the end of the message.
Fix internal errors like:
ld: BFD (GNU Binutils) 2.26.51.20160526 internal error, aborting at .../bfd/elfxx-mips.c:10278 in _bfd_mips_elf_relocate_section
ld: Please report this bug.
triggered by the `bfd_reloc_outofrange' condition on branch relocations.
bfd/
* elfxx-mips.c (b_reloc_p): New function.
(_bfd_mips_elf_relocate_section) <bfd_reloc_outofrange>: Handle
branch relocations.
ld/
* testsuite/ld-mips-elf/unaligned-branch.d: New test.
* testsuite/ld-mips-elf/unaligned-branch.s: New test source.
* testsuite/ld-mips-elf/unaligned-text.s: New test source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
The original MIPS SVR4 psABI defines the calculation for the R_MIPS_26
relocation in a complex way, as follows[1]:
Name Value Field Symbol Calculation
R_MIPS_26 4 T-targ26 local (((A << 2) | \
(P & 0xf0000000)) + S) >> 2
4 T-targ26 external (sign-extend(A << 2) + S) >> 2
This is further clarified, by correcting typos (already applied in the
excerpt above) in the 64-bit psABI extension[2]. A note is included in
both documents to specify that for the purpose of relocation processing
a local symbol is one with binding STB_LOCAL and type STT_SECTION, and
otherwise, a symbol is external.
We have both calculations implemented for the R_MIPS_26 relocation, and
by extension also for the R_MIPS16_26 and R_MICROMIPS_26_S1 relocations,
from now on collectively called jump relocations. However our code uses
a different condition to tell local and external symbols apart, that is
it only checks for the STB_LOCAL binding and ignores the symbol type,
however for REL relocations only. The external calculation is used for
all RELA jump relocations.
In reality the difference matters for jump relocations referring local
MIPS16 and, as from recent commit 44d3da2338 ("MIPS/GAS: Treat local
jump relocs the same no matter if REL or RELA"), also local microMIPS
symbols. Such relocations are not converted to refer to corresponding
section symbols instead and retain the original local symbol reference.
It can be inferred from the relocation calculation definitions that the
addend is effectively unsigned for the local case and explicitly signed
for the external case. With the REL relocation format it makes sense
given the limited range provided for by the field being relocated: the
use of an unsigned addend expands the range by one bit for the local
case, because a negative offset from a section symbol makes no sense,
and any usable negative offset from the original local symbol will have
worked out positive if converted to a section-relative reference. In
the external case a signed addend gives more flexibility as offsets both
negative and positive can be used with a symbol. Any such offsets will
typically have a small value.
The inclusion of the (P & 0xf0000000) component, ORed in the calculation
in the local case, seems questionable as bits 31:28 are not included in
the relocatable field and are masked out as the relocation is applied.
Their value is therefore irrelevant for output processing, the relocated
field ends up the same regardless of their value. They could be used
for overflow detection, however this is precluded by adding them to bits
31:28 of the symbol referred, as the sum will not correspond to the
value calculated by the processor at run time whenever bits 31:28 of the
symbol referred are not all zeros, even though it is valid as long they
are the same as bits 31:28 of P.
We deal with this problem by ignoring any overflow resulting from the
local calculation. This however makes us miss genuine overflow cases,
where 31:28 of the symbol referred are different from bits 31:28 of P,
and non-functional code is produced.
Given the situation, for the purpose of overflow detection we can change
our code to follow the original psABI and only treat the in-place addend
as unsigned in the section symbol case, permitting jumps to offsets
128MiB and above into section. Sections so large may be uncommon, but
still a reasonable use case. On the other hand such large offsets from
regular local symbols are not expected and it makes sense to support
(possibly small) negative offsets instead, also in consistency with what
we do for global symbols.
Drop the (P & 0xf0000000) component then, treat the addend as signed
with local non-section symbols and also detect an overflow in the result
of such calculation with local symbols. NB it does not affect the value
computed for the relocatable field, it only affects overflow detection.
References:
[1] "SYSTEM V APPLICATION BINARY INTERFACE, MIPS RISC Processor
Supplement, 3rd Edition", Figure 4-11: "Relocation Types", p. 4-19
<http://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf>
[2] "64-bit ELF Object File Specification, Draft Version 2.5", Table 32
"Relocation Types", p. 45
<http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf>
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation): <R_MIPS16_26>
<R_MIPS_26, R_MICROMIPS_26_S1>: Drop the region bits of the
reloc location from calculation, treat the addend as signed with
local non-section symbols and enable overflow detection.
ld/
* testsuite/ld-mips-elf/jal-global-overflow-0.d: New test.
* testsuite/ld-mips-elf/jal-global-overflow-1.d: New test.
* testsuite/ld-mips-elf/jal-local-overflow-0.d: New test.
* testsuite/ld-mips-elf/jal-local-overflow-1.d: New test.
* testsuite/ld-mips-elf/jal-global-overflow.s: New test source.
* testsuite/ld-mips-elf/jal-local-overflow.s: New test source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
On RELA targets the addend can affect JALX target's alignment, so only
verify it once the whole relocation calculation has completed.
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation) <R_MIPS16_26>
<R_MIPS_26, R_MICROMIPS_26_S1>: Include the addend in JALX's
target alignment verification.
ld/
* testsuite/ld-mips-elf/unaligned-jalx-addend-0.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-1.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-mips16-0.d: New
test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-mips16-1.d: New
test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-micromips-0.d: New
test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-micromips-1.d: New
test.
* testsuite/ld-mips-elf/unaligned-jalx-addend-0.s: New test
source.
* testsuite/ld-mips-elf/unaligned-jalx-addend-1.s: New test
source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
Symbol table entries for section symbols are different between IRIX and
traditional MIPS ELF targets in that IRIX entries have their `st_name'
member pointing at the section's name in the string table section, while
traditional entries have 0 there and the section header string table has
to be referred via the relevant section header's `shn_name' member
instead.
This is chosen with the `elf_backend_name_local_section_symbols' backend
and can be observed with `readelf -s' output for an IRIX object:
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1 .text
2: 00000000 0 SECTION LOCAL DEFAULT 3 .data
3: 00000000 0 SECTION LOCAL DEFAULT 4 .bss
4: 00000000 0 SECTION LOCAL DEFAULT 5 .reginfo
5: 00000000 0 SECTION LOCAL DEFAULT 6 .MIPS.abiflags
6: 00000000 0 SECTION LOCAL DEFAULT 7 .pdr
7: 00000000 0 SECTION LOCAL DEFAULT 9 .gnu.attributes
8: 00002000 16 FUNC GLOBAL DEFAULT 1 foo
9: 00004008 0 FUNC LOCAL DEFAULT 1 abar
10: 00002008 0 FUNC LOCAL DEFAULT 1 afoo
11: 00004000 16 FUNC GLOBAL DEFAULT 1 bar
and a corresponding traditional object:
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1
2: 00000000 0 SECTION LOCAL DEFAULT 3
3: 00000000 0 SECTION LOCAL DEFAULT 4
4: 00004008 0 FUNC LOCAL DEFAULT 1 abar
5: 00002008 0 FUNC LOCAL DEFAULT 1 afoo
6: 00000000 0 SECTION LOCAL DEFAULT 5
7: 00000000 0 SECTION LOCAL DEFAULT 6
8: 00000000 0 SECTION LOCAL DEFAULT 7
9: 00000000 0 SECTION LOCAL DEFAULT 9
10: 00002000 16 FUNC GLOBAL DEFAULT 1 foo
11: 00004000 16 FUNC GLOBAL DEFAULT 1 bar
respectively. Consequently the right way to retrieve a section symbol's
name has to be chosen in `mips_elf_calculate_relocation' for the purpose
of error reporting.
Originally we produced symbol tables in the traditional object format
only and we handled it correctly until it was lost in a rewrite with:
commit 7403cb6305
Author: Mark Mitchell <mark@codesourcery.com>
Date: Wed Jun 30 20:13:43 1999 +0000
probably because of the extra pointer indirection added which made the
same expression have a different meaning.
With the addition of IRIX symbol table format with:
commit 174fd7f955
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date: Mon Feb 9 08:04:00 2004 +0000
the bug has been partially covered and now when a relocation error is
triggered with an IRIX object the offending section symbol is correctly
reported:
tmpdir/dump0.o: In function `foo':
(.text+0x2000): relocation truncated to fit: R_MIPS_26 against `.text'
tmpdir/dump0.o: In function `bar':
(.text+0x4000): relocation truncated to fit: R_MIPS_26 against `.text'
because `bfd_elf_string_from_elf_section' retrieves the name from the
string table section. With a traditional object however the function
returns an empty string and consequently `no symbol' is printed instead:
tmpdir/dump0.o: In function `foo':
(.text+0x2000): relocation truncated to fit: R_MIPS_26 against `no symbol'
tmpdir/dump0.o: In function `bar':
(.text+0x4000): relocation truncated to fit: R_MIPS_26 against `no symbol'
Restore the original semantics so that the section name is always
correctly retrieved.
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation): Also use the
section name if `bfd_elf_string_from_elf_section' returns an
empty string.
ld/
* testsuite/ld-mips-elf/reloc-local-overflow.d: New test.
* testsuite/ld-mips-elf/reloc-local-overflow.s: Source for the
new test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
Upon a `bfd_reloc_outofrange' error continue processing so that any
further issues are also reported, similarly to how `bfd_reloc_overflow'
is handled. Adjust message formatting accordingly, using `%X' to abort
processing at conclusion.
Reduce the number of test cases by grouping relocations the handling of
which can now be verified together with a single source and dump.
bfd/
* elfxx-mips.c (_bfd_mips_elf_relocate_section)
<bfd_reloc_outofrange>: Use the `%X%H' rather than `%C' format
for message. Continue processing rather than returning failure.
ld/
* testsuite/ld-mips-elf/unaligned-jalx-0.d: Fold
`unaligned-jalx-2' here.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-0.d: Fold
`unaligned-jalx-mips16-2' here.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-0.d: Fold
`unaligned-jalx-micromips-2' here.
* testsuite/ld-mips-elf/unaligned-jalx-0.s: Update accordingly.
* testsuite/ld-mips-elf/unaligned-jalx-1.d: Update error
message.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-1.d: Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-1.d: Likewise.
* testsuite/ld-mips-elf/unaligned-jalx-2.d: Remove test.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-2.d: Remove test.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-2.d: Remove
test.
* testsuite/ld-mips-elf/unaligned-jalx-2.s: Remove test source.
* testsuite/ld-mips-elf/unaligned-lwpc-0.d: Fold
`unaligned-lwpc-3' here.
* testsuite/ld-mips-elf/unaligned-lwpc-0.s: Update accordingly.
* testsuite/ld-mips-elf/unaligned-lwpc-1.d: Fold
`unaligned-lwpc-2' here.
* testsuite/ld-mips-elf/unaligned-lwpc-1.s: Update accordingly.
* testsuite/ld-mips-elf/unaligned-lwpc-2.d: Remove test.
* testsuite/ld-mips-elf/unaligned-lwpc-2.s: Remove test source.
* testsuite/ld-mips-elf/unaligned-lwpc-3.d: Remove test.
* testsuite/ld-mips-elf/unaligned-lwpc-3.s: Remove test source.
* testsuite/ld-mips-elf/unaligned-ldpc-0.d: Fold
`unaligned-ldpc-4' here.
* testsuite/ld-mips-elf/unaligned-ldpc-0.s: Update accordingly.
* testsuite/ld-mips-elf/unaligned-ldpc-1.d: Update error
message. Fold `unaligned-ldpc-2' and `unaligned-ldpc-3' here.
* testsuite/ld-mips-elf/unaligned-ldpc-1.s: Update accordingly.
* testsuite/ld-mips-elf/unaligned-ldpc-2.d: Remove test.
* testsuite/ld-mips-elf/unaligned-ldpc-2.s: Remove test source.
* testsuite/ld-mips-elf/unaligned-ldpc-3.d: Remove test.
* testsuite/ld-mips-elf/unaligned-ldpc-3.s: Remove test source.
* testsuite/ld-mips-elf/unaligned-ldpc-4.d: Remove test.
* testsuite/ld-mips-elf/unaligned-ldpc-4.s: Remove test source.
* testsuite/ld-mips-elf/mips-elf.exp: Delete removed tests.
A `bfd_reloc_outofrange' condition from `mips_elf_calculate_relocation'
currently triggers the warning callback, which in the case of LD prints
messages like:
foo.o: In function `foo':
(.text+0x0): warning: JALX to a non-word-aligned address
or:
foo.o: In function `foo':
(.text+0x0): warning: PC-relative load from unaligned address
and nothing else, which suggests this is a benign condition and link has
otherwise successfully run to completion. This is however not the case,
the link terminates right away with no further messages and no output
produced.
Use the general error or warning info callback then, preserving the
message format. Also set a BFD error condition so that a failure is
unambiguously reported. Complement the change with a set of suitable
test suite additions.
bfd/
* elfxx-mips.c (_bfd_mips_elf_relocate_section)
<bfd_reloc_outofrange>: Call `->einfo' rather than `->warning'.
Call `bfd_set_error'.
ld/
* testsuite/ld-mips-elf/unaligned-jalx-0.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-1.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-2.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-0.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-1.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-mips16-2.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-0.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-1.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-micromips-2.d: New test.
* testsuite/ld-mips-elf/unaligned-lwpc-0.d: New test.
* testsuite/ld-mips-elf/unaligned-lwpc-1.d: New test.
* testsuite/ld-mips-elf/unaligned-lwpc-2.d: New test.
* testsuite/ld-mips-elf/unaligned-lwpc-3.d: New test.
* testsuite/ld-mips-elf/unaligned-ldpc-0.d: New test.
* testsuite/ld-mips-elf/unaligned-ldpc-1.d: New test.
* testsuite/ld-mips-elf/unaligned-ldpc-2.d: New test.
* testsuite/ld-mips-elf/unaligned-ldpc-3.d: New test.
* testsuite/ld-mips-elf/unaligned-ldpc-4.d: New test.
* testsuite/ld-mips-elf/unaligned-jalx-0.s: New test source.
* testsuite/ld-mips-elf/unaligned-jalx-1.s: New test source.
* testsuite/ld-mips-elf/unaligned-jalx-2.s: New test source.
* testsuite/ld-mips-elf/unaligned-insn.s: New test source.
* testsuite/ld-mips-elf/unaligned-lwpc-0.s: New test source.
* testsuite/ld-mips-elf/unaligned-lwpc-1.s: New test source.
* testsuite/ld-mips-elf/unaligned-lwpc-2.s: New test source.
* testsuite/ld-mips-elf/unaligned-lwpc-3.s: New test source.
* testsuite/ld-mips-elf/unaligned-ldpc-0.s: New test source.
* testsuite/ld-mips-elf/unaligned-ldpc-1.s: New test source.
* testsuite/ld-mips-elf/unaligned-ldpc-2.s: New test source.
* testsuite/ld-mips-elf/unaligned-ldpc-3.s: New test source.
* testsuite/ld-mips-elf/unaligned-ldpc-4.s: New test source.
* testsuite/ld-mips-elf/unaligned-syms.s: New test source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
The microMIPS JALX instruction shares the R_MICROMIPS_26_S1 relocation
with microMIPS J/JAL/JALS instructions, however unlike the latters its
encoded immediate argument is unusually shifted left by 2 rather than 1
in calculating the value used for the operation requested.
We already handle this exception in `mips_elf_calculate_relocation' in
LD, in a scenario where JALX is produced as a result of relaxing JAL for
the purpose of making a cross-mode jump. We also get it right in the
disassembler in `decode_micromips_operand'.
What we don't correctly do however is processing microMIPS JALX produced
by GAS from an assembly source, where a non-zero constant argument or a
symbol reference with a non-zero in-place addend has been used. In this
case the same calculation is made as for microMIPS J/JAL/JALS, causing
the wrong encoding to be produced by GAS on making an object file, and
then again by LD in the final link. The latter in particular causes the
calculation, where the addend fits in the relocatable field, to produce
different final addresses for the same source code depending on whether
REL or RELA relocations are used.
Correct these issues by special-casing microMIPS JALX in the places that
have been previously missed.
bfd/
* elfxx-mips.c (mips_elf_read_rel_addend): Adjust the addend for
microMIPS JALX.
gas/
* config/tc-mips.c (append_insn): Correct the encoding of a
constant argument for microMIPS JALX.
(tc_gen_reloc): Correct the encoding of an in-place addend for
microMIPS JALX.
* testsuite/gas/mips/jalx-addend.d: New test.
* testsuite/gas/mips/jalx-addend-n32.d: New test.
* testsuite/gas/mips/jalx-addend-n64.d: New test.
* testsuite/gas/mips/jalx-imm.d: New test.
* testsuite/gas/mips/jalx-imm-n32.d: New test.
* testsuite/gas/mips/jalx-imm-n64.d: New test.
* testsuite/gas/mips/jalx-addend.s: New test source.
* testsuite/gas/mips/jalx-imm.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.
ld/
* testsuite/ld-mips-elf/jalx-addend.d: New test.
* testsuite/ld-mips-elf/jalx-addend-n32.d: New test.
* testsuite/ld-mips-elf/jalx-addend-n64.d: New test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
Just mask higher bits off, which returns the same set of 3-bit register
encodings of { 0, 1, 2, 3, 4, 5, 6, 7 } for the allowed 5-bit encodings
of { 16, 17, 2, 3, 4, 5, 6, 7 }. Input has already been validated with
OP16_VALID_REG.
bfd/
* elfxx-mips.c (BZ16_REG_FIELD): Simplify calculation.
Factor out the parts of `_bfd_mips_elf_merge_private_bfd_data'
responsible for ABI flag merging to `mips_elf_merge_obj_abiflags'. No
functional change.
bfd/
* elfxx-mips.c (mips_elf_merge_obj_abiflags): New function,
factored out from...
(_bfd_mips_elf_merge_private_bfd_data): ... here.
We have a problem in that in making compatibility checks while merging
private BFD data on the MIPS target we give priority to the attribute
check, which may fail and cause the function to abort early on. The
problem with this is the ABI compatibility aspect recorded in the
attributes is relatively minor compared to aspects recorded in the ELF
file header. However the premature exit causes any more important
compatibility aspect violated to be masked and not reported to the user
once a problem with attributes has been noticed.
So move the attribute check after the ELF file header flag check in
`_bfd_mips_elf_merge_private_bfd_data', and do not return prematurely
there. Take advantage of the resulting grouping of ELF file header
handling together and remove the premature success return point for the
first input object being handled, letting the code later on figure out
output ABI flags even for this object.
Update LD test cases according to messages from ELF file header checks
now preceding ones from attribute checks.
bfd/
* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Move
attribute check after ELF file header flag check.
ld/
* testsuite/ld-mips-elf/attr-gnu-4-14.d: Update the order of
messages expected according to MIPS BFD private data merge
changes.
* testsuite/ld-mips-elf/attr-gnu-4-24.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-34.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-41.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-42.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-43.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-45.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-46.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-47.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-48.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-49.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-54.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-64.d: Likewise.
* testsuite/ld-mips-elf/attr-gnu-4-74.d: Likewise.
Fix the issue of any failure from `_bfd_elf_merge_object_attributes' not
being propagated by `mips_elf_merge_obj_attributes'.
bfd/
* elfxx-mips.c (mips_elf_merge_obj_attributes): Propagate the
return status from `_bfd_elf_merge_object_attributes'.
Factor out the parts of `_bfd_mips_elf_merge_private_bfd_data'
responsible for ELF file header flag compatibility checks to
`mips_elf_merge_obj_e_flags'. As a side effect remove a premature
return point from `_bfd_mips_elf_merge_private_bfd_data'. No functional
change otherwise.
bfd/
* elfxx-mips.c (mips_elf_merge_obj_e_flags): New function,
factored out from...
(_bfd_mips_elf_merge_private_bfd_data): ... here.
Fold the handling of input MIPS ABI flags in private BFD data merging
together, moving the attribute check afterwards, and consequently making
input vs output compatibility checks only start once all input ABI flag
data has been gathered, checked for inconsistencies and put in order.
Consequently also address the issue of input ABI flag inconsistencies
being masked by a failing attribute check, which currently makes
`_bfd_mips_elf_merge_private_bfd_data' exit prematurely and therefore
prevent input ABI flag inconsistencies from being reported. Such
inconsistencies need to be reported as they may be the very cause of an
attribute check failure.
bfd/
* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Fold the
handling of input MIPS ABI flags together.
We currently special-case the handling of attribute checks on input
objects and make them even before we check a given input object actually
contains any sections. This does not add value as empty objects do not
cause a compatibility concern and we already make this observation for
other properties such as ELF file header flags. Moreover the attributes
themselves are stored in a `.gnu.attributes' section so the absence of
any section (except from a few special cases) implies there have been no
attributes provided either. Therefore it is safe to move the attribute
checks later on, after the null-section check has been made.
bfd/
* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Suppress
attribute checks for null input.
Use local pointers to target data to reduce the amount of indirection
and improve the readability of `_bfd_mips_elf_merge_private_bfd_data'.
bfd/
* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Use local
pointers to target data.
Correct a warning produced on any FP ABI mismatch observed. Unlike the
other settings, which in the presence of `.MIPS.abiflags' are duplicated
in the `e_flags' member of the ELF file header, information on the FP
ABI in use is duplicated in `.gnu.attributes' rather than in the former
place. Update the warning message accordingly.
bfd/
* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Correct
an FP ABI warning.
bfd/
* elfxx-mips.c (mips_elf_check_mips16_stubs): Set a stub's output
section to bfd_abs_section_ptr if the stub is discarded.
ld/testsuite/
* ld-mips-elf/mips16-fp-stub-1.s: New.
* ld-mips-elf/mips16-fp-stub-2.s: New.
* ld-mips-elf/mips16-fp-stub.d: New.
* ld-mips-elf/mips-elf.exp: Run new tests.
* ld-mips-elf/mips16-intermix.d: Update expected output.
https://sourceware.org/ml/binutils/2015-10/msg00137.html
bfd PR ld/18401
* elfxx-mips.c (bfd_mips_isa_ext_mach): New function: Converts an
ISA value to a bfd machine number.
(bfd_mips_isa_ext): Update the ISA level and revision if
necessary. Use mips_mach_extends_p to decide if the ISA extension
needs to be set.
(_bfd_mips_elf_merge_private_bfd_data): Allow the ISA extension to
be inferred from the ABI setting. Set the ISA level from the
maximum of the incoming and outgoing ISA levels.
tests
* ld-mips-elf/mips-elf-flags.exp: Add more ISA conflict tests.
For the case of MIPS n64 target and 32-bit host, the computation of
the DT_MIPS_RLD_MAP_REL tag involves sdyn->output_section->vma +
sdyn->output_offset (64-bit) being added to b (32-bit host pointer),
so losing the high part and resulting in an incorrect
DT_MIPS_RLD_MAP_REL tag, and all dynamically linked glibc tests
failing for n64. This patch fixes this (spot-tested with glibc tests;
however, I don't have a self-contained testcase for this bug).
* elfxx-mips.c (_bfd_mips_elf_finish_dynamic_sections)
<DT_MIPS_RLD_MAP_REL>: Add target address to host address
difference, not to host pointer.
Alan Modra
Maciej W. Rozycki
Nick Clifton
Matthew Fortune
Faraz Shahbazker
Catherine Moore
Rich Felker
H.J. Lu
Simon Dardis
Joseph Myers