2016-12-01 Cary Coutant <ccoutant@gmail.com>
Igor Kudrin <ikudrin@accesssoftek.com>
PR gold/20717
* script-sections.cc (Script_sections): Set *keep to false when
no match.
2016-12-11 Igor Kudrin <ikudrin@accesssoftek.com>
PR gold/20717
* testsuite/Makefile.am (pr20717): New test.
* testsuite/Makefile.in: Regenerate.
* testsuite/pr20717.c: New test source file.
* testsuite/pr20717.sh: New test script.
* testsuite/pr20717.t: New test linker script.
PR 16711 noted that gold allocates file space for BSS sections when using
a linker script. I've fixed that by rewriting set_section_addresses and
set_section_list_addresses to track the file offset separate from the
current virtual address, so that BSS sections do not move the file offset.
Now, if a series of BSS sections come at the end of a segment, we do not
allocate file space; but if a script forces them into the middle of a
segment, we will still allocate file space (matching Gnu ld behavior).
I've also added a warning when that happens.
That exposed another problem where orphan .bss sections were sometimes
placed in the middle of a segment. For example, if the script mentions
the .got section, but both .data and .bss are orphans, gold would put
both .data and .bss in front of .got. I've fixed that by ensuring that
orphan BSS sections are always placed after all other allocated sections.
It also exposed a problem where the SUBALIGN property is not handled
properly. The ld manual clearly states that it should override input section
alignment, whether greater or less than the given alignment, but gold would
only increase an input section's alignment. Gold would also place the output
section based on its original alignment before the SUBALIGN property took
effect, leading to a misaligned output section (where the input section
was properly aligned in memory, but was not aligned relative to the start
of the section), in violation of the ELF/gABI spec. I've fixed that by
making sure that the SUBALIGN property overrides the internal alignment of
the input sections as well as the external alignment of the output section.
This affected the behavior of script_test_2, which was written to expect
a misaligned section.
The net effect is, I think, improved compatibility with the BFD linker.
There are still cases where orphan placement differs, but the differences
should be rarer and less important. ALIGN and SUBALIGN behavior is closer,
but still not an exact match -- I still found cases where ld would create
a misaligned output section, and where gold will properly align it.
gold/
PR gold/16711
* output.cc (Output_section::set_final_data_size): Calculate data size
based on relative offset rather than file offset.
(Output_segment::set_section_addresses): Track file offset separately
from address offset.
(Output_segment::set_section_list_addresses): Add pfoff parameter.
Track file offset separately. Don't move file offset for BSS
sections.
* output.h (Output_segment::set_section_list_addresses): Add pfoff
parameter.
* script-sections.cc (Orphan_section_placement): Add PLACE_LAST_ALLOC.
(Orphan_section_placement::Orphan_section_placement): Initialize it.
(Orphan_section_placement::output_section_init): Track last allocated
section.
(Orphan_section_placement::find_place): Place BSS after last allocated
section.
(Output_section_element_input::set_section_addresses): Always override
input section alignment when SUBALIGN is specified.
(Output_section_definition::set_section_addresses): Override alignment
of output section when SUBALIGN is specified.
* testsuite/Makefile.am (script_test_15a, script_test_15b)
(script_test_15c): New test cases.
* testsuite/Makefile.in: Regenerate.
* testsuite/script_test_2.cc: Adjust expected layout.
* testsuite/script_test_15.c: New source file.
* testsuite/script_test_15a.sh: New shell script.
* testsuite/script_test_15a.t: New linker script.
* testsuite/script_test_15b.sh: New shell script.
* testsuite/script_test_15b.t: New linker script.
* testsuite/script_test_15c.sh: New shell script.
* testsuite/script_test_15c.t: New linker script.
This code has never been used throughout the repository history, and
likely not before either, as due to the assymetry of MIPS16 instruction
set encoding there are no 32-bit shift operations having their immediate
shift count placed in the position of the usual `rx' instruction field.
gas/
* config/tc-mips.c (mips16_macro_build) <'>'>: Remove case.
include/
* opcode/mips.h: Remove references to `>' operand code.
opcodes/
* mips16-opc.c (decode_mips16_operand) <'>'>: Remove cases.
Make the `e' operand code used with raw EXTEND instructions use the
hexadecimal rather than decimal format, for consistency with what is
actually produced by code in `print_insn_mips16' dedicated to EXTEND
disassembly. Due to that special handling the operand code is only
interpreted for assembly however, which accepts either format either
way, so there is no functional change here.
opcodes/
* mips16-opc.c (decode_mips16_operand) <'e'>: Use HINT rather
than UINT.
gas/
* testsuite/gas/mips/mips16-extend.d: New test.
* testsuite/gas/mips/mips16-extend.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new test.
Use a tab rather than a space to separate `extend' and its uninterpreted
argument output, like with regular instructions. Separate hexadecimal
halves of undecoded extended instructions output with a space instead of
presenting them concatenated.
opcodes/
* mips-dis.c (print_insn_mips16): Use a tab rather than a space
to separate `extend' and its uninterpreted argument output.
Separate hexadecimal halves of undecoded extended instructions
output.
binutils/
* testsuite/binutils-all/mips/mips16-extend-noinsn.d: New test.
* testsuite/binutils-all/mips/mips16-extend-noinsn.s: New test
source.
* testsuite/binutils-all/mips/mips.exp: Run the new test.
I build GDB with all targets enabled, and "set architecture rx",
GDB crashes,
(gdb) set architecture rx
Program received signal SIGSEGV, Segmentation fault.
append_flags_type_flag (type=0x20cc360, bitpos=bitpos@entry=0, name=name@entry=0xd27529 "C") at ../../binutils-gdb/gdb/gdbtypes.c:4926
4926 name);
(gdb) bt 10
#0 append_flags_type_flag (type=0x20cc360, bitpos=bitpos@entry=0, name=name@entry=0xd27529 "C") at ../../binutils-gdb/gdb/gdbtypes.c:4926
#1 0x00000000004ce725 in rx_gdbarch_init (info=..., arches=<optimized out>) at ../../binutils-gdb/gdb/rx-tdep.c:1051
#2 0x00000000006b05a4 in gdbarch_find_by_info (info=...) at ../../binutils-gdb/gdb/gdbarch.c:5269
#3 0x000000000060eee4 in gdbarch_update_p (info=...) at ../../binutils-gdb/gdb/arch-utils.c:557
#4 0x000000000060f8a8 in set_architecture (ignore_args=<optimized out>, from_tty=1, c=<optimized out>) at ../../binutils-gdb/gdb/arch-utils.c:531
#5 0x0000000000593d0b in do_set_command (arg=<optimized out>, arg@entry=0x20bee81 "rx ", from_tty=from_tty@entry=1, c=c@entry=0x20b1540)
at ../../binutils-gdb/gdb/cli/cli-setshow.c:455
#6 0x00000000007665c3 in execute_command (p=<optimized out>, p@entry=0x20bee70 "set architecture rx ", from_tty=1) at ../../binutils-gdb/gdb/top.c:666
#7 0x00000000006935f4 in command_handler (command=0x20bee70 "set architecture rx ") at ../../binutils-gdb/gdb/event-top.c:577
#8 0x00000000006938d8 in command_line_handler (rl=<optimized out>) at ../../binutils-gdb/gdb/event-top.c:767
#9 0x0000000000692c2c in gdb_rl_callback_handler (rl=0x20be7f0 "") at ../../binutils-gdb/gdb/event-top.c:200
The cause is that we want to access some builtin types in gdbarch init, but
it is not initialized yet. I fix it by creating the type when it is to be
used. We've already done this in sparc, sparc64 and m68k.
gdb:
2016-12-09 Yao Qi <yao.qi@linaro.org>
PR tdep/20954
* rx-tdep.c (rx_psw_type): New function.
(rx_fpsw_type): New function.
(rx_register_type): Call rx_psw_type and rx_fpsw_type.
(rx_gdbarch_init): Move code to rx_psw_type and
rx_fpsw_type.
gdb/testsuite:
2016-12-09 Yao Qi <yao.qi@linaro.org>
* gdb.base/all-architectures.exp.in: Remove kfail for "rx".
I build GDB for all targets enabled. When I "set architecture rl78",
GDB crashes,
(gdb) set architecture rl78
Program received signal SIGSEGV, Segmentation fault.
append_flags_type_flag (type=0x20cc0e0, bitpos=bitpos@entry=0, name=name@entry=0x11dba3f "CY") at ../../binutils-gdb/gdb/gdbtypes.c:4926
4926 name);
(gdb) bt 10
#0 append_flags_type_flag (type=0x20cc0e0, bitpos=bitpos@entry=0, name=name@entry=0x11dba3f "CY") at ../../binutils-gdb/gdb/gdbtypes.c:4926
#1 0x00000000004aaca8 in rl78_gdbarch_init (info=..., arches=<optimized out>) at ../../binutils-gdb/gdb/rl78-tdep.c:1410
#2 0x00000000006b05a4 in gdbarch_find_by_info (info=...) at ../../binutils-gdb/gdb/gdbarch.c:5269
#3 0x000000000060eee4 in gdbarch_update_p (info=...) at ../../binutils-gdb/gdb/arch-utils.c:557
#4 0x000000000060f8a8 in set_architecture (ignore_args=<optimized out>, from_tty=1, c=<optimized out>) at ../../binutils-gdb/gdb/arch-utils.c:531
#5 0x0000000000593d0b in do_set_command (arg=<optimized out>, arg@entry=0x20be851 "rl78", from_tty=from_tty@entry=1, c=c@entry=0x20b1540)
at ../../binutils-gdb/gdb/cli/cli-setshow.c:455
#6 0x00000000007665c3 in execute_command (p=<optimized out>, p@entry=0x20be840 "set architecture rl78", from_tty=1) at ../../binutils-gdb/gdb/top.c:666
#7 0x00000000006935f4 in command_handler (command=0x20be840 "set architecture rl78") at ../../binutils-gdb/gdb/event-top.c:577
#8 0x00000000006938d8 in command_line_handler (rl=<optimized out>) at ../../binutils-gdb/gdb/event-top.c:767
#9 0x0000000000692c2c in gdb_rl_callback_handler (rl=0x20be890 "") at ../../binutils-gdb/gdb/event-top.c:200
The cause is that we want to access some builtin types in gdbarch init, but
it is not initialized yet. I fix it by creating the type when it is to be
used. We've already done this in sparc, sparc64 and m68k.
gdb:
2016-12-09 Yao Qi <yao.qi@linaro.org>
PR tdep/20953
* rl78-tdep.c (rl78_psw_type): New function.
(rl78_register_type): Call rl78_psw_type.
(rl78_gdbarch_init): Move code to rl78_psw_type.
gdb/testsuite:
2016-12-09 Yao Qi <yao.qi@linaro.org>
* gdb.base/all-architectures.exp.in: Remove kfail for rl78.
This adds a test that exposes several problems fixed by earlier
patches:
#1 - Buffer overrun when host/target formats match, but sizes don't.
https://sourceware.org/ml/gdb-patches/2016-03/msg00125.html#2 - Missing handling for FR-V FR300.
https://sourceware.org/ml/gdb-patches/2016-03/msg00117.html#3 - BFD architectures with spaces in their names (v850).
https://sourceware.org/ml/binutils/2016-03/msg00108.html#4 - The OS ABI names with spaces issue.
https://sourceware.org/ml/gdb-patches/2016-03/msg00116.html#5 - Bogus HP/PA long double format.
https://sourceware.org/ml/gdb-patches/2016-03/msg00122.html#6 - Cris big endian internal error.
https://sourceware.org/ml/gdb-patches/2016-03/msg00126.html#7 - Several PowerPC bfd archs/machines not handled by gdb.
https://sourceware.org/bugzilla/show_bug.cgi?id=19797
And hopefully helps catch others in the future.
This started out as a test that simply did,
gdb -ex "print 1.0L"
to exercise #1 above.
Then to cover both 32-bit target / 64-bit host and the converse, I
thought of having the testcase print the floats twice, once with the
architecture set to "i386" and then to "i386:x86-64". This way it
wouldn't matter whether gdb was built as 32-bit or a 64-bit program.
Then I thought that other archs might have similar host/target
floatformat conversion issues as well. Instead of hardcoding some
architectures in the test file, I thought we could just iterate over
all bfd architectures and OS ABIs supported by the gdb build being
tested. This is what then exposed all the other problems listed
above...
With an --enable-targets=all, this exercises over 14 thousand
combinations. If left in a single test file, it all consistenly runs
in under a minute on my machine (An Intel i7-4810MQ @ 2.8 MHZ running
Fedora 23). Split in 8 chunks, as in this commit, it runs in around
25 seconds, with make -j8.
To avoid flooding the gdb.sum file, it avoids calling "pass" on each
tested combination/iteration. I'm explicitly not implementing that by
passing an empty message to gdb_test / gdb_test_multiple, because I
still want a FAIL to be logged in gdb.sum. So instead this puts the
internal passes in the gdb.log file, only, prefixed "IPASS:", for
internal pass. TBC, if some iteration fails, it'll still show up as
FAIL in gdb.sum. If this is an approach that takes on, I can see us
extending the common bits to support it for all testcases.
gdb/testsuite/ChangeLog:
2016-12-09 Pedro Alves <palves@redhat.com>
* gdb.base/all-architectures-0.exp: New file.
* gdb.base/all-architectures-1.exp: New file.
* gdb.base/all-architectures-2.exp: New file.
* gdb.base/all-architectures-3.exp: New file.
* gdb.base/all-architectures-4.exp: New file.
* gdb.base/all-architectures-5.exp: New file.
* gdb.base/all-architectures-6.exp: New file.
* gdb.base/all-architectures-7.exp: New file.
* gdb.base/all-architectures.exp.in: New file.
This patch change aarch prologue analyzer using code cache, in order
to improve the performance of remote debugging.
gdb.perf/skip-prologue.exp (measured by wall-time) is improved when
the program is compiled without debug information.
Original Patched Original Patched
without dbg without dbg with dbg with dbg
/ 11.1635239124 9.99472999573 9.65339517593 9.66648793221
-fstack-protector-all 11.2560930252 9.338118 9.63896489143 9.59474396706
gdb:
2016-12-9 Yao Qi <yao.qi@linaro.org>
* aarch64-tdep.c (instruction_reader::read): Call
read_code_unsigned_integer instead of
read_memory_unsigned_integer.
This patch change arm prologue analyzer using code cache, in order
to improve the performance of remote debugging.
gdb.perf/skip-prologue.exp (measured by wall-time) is improved a lot,
Original Patched Original Patched
without dbg without dbg with dbg with dbg
-marm 14.166741848 9.32852292061 11.4908499718 9.16302204132
-marm 14.6705040932 9.34849786758 18.2788009644 9.14823913574
\-fstack-protector-all
-mthumb 34.4391930103 10.6062178612 13.7886838913 10.3094120026
-mthumb
\-fstack-protector-all 34.9310460091 10.6413481236 25.3875930309 10.6294929981
gdb:
2016-12-09 Yao Qi <yao.qi@linaro.org>
* arm-tdep.c (skip_prologue_function): Call
read_code_unsigned_integer instead of
read_memory_unsigned_integer.
(thumb_analyze_prologue): Likewise.
(arm_analyze_load_stack_chk_guard): Likewise.
(arm_skip_stack_protector): Likewise.
(arm_analyze_prologue):Likewise.
(extend_buffer_earlier): Call target_read_code instead
of target_read_memory.
(arm_adjust_breakpoint_address): Likewise.
gdb.perf/skip-prologue.exp is intended to measure the performance of
skipping prologue with prologue analysis by setting breakpoints.
However, if program is compiled with debug info, GDB is smart to
skip prologue by line table from debug info, so prologue analysis
is not exercised at all.
This patch adds a parameter COMPILE to specify compiling with
debug information, otherwise, it is compiled without debug
information.
gdb/testsuite:
2016-12-09 Yao Qi <yao.qi@linaro.org>
* gdb.perf/skip-prologue.exp: Add parameter COMPILE.
For "info threads", we currently run into:
$ gdb/gdb -q -nw -nx --batch -ex start -ex info\ threads bfd/doc/chew
Temporary breakpoint 1 at 0x80486e0: file ../../../W._C._Handy/bfd/doc/chew.c, line 1535.
[New Thread 10656.5]
Thread 4 hit Temporary breakpoint 1, main (ac=1, av=0x102cd84) at ../../../W._C._Handy/bfd/doc/chew.c:1535
1535 {
Id Target Id Frame
1 bogus thread id 1 Can't fetch registers from thread bogus thread id 1: No such thread
Before commit e8032dde10,
gdb/thread.c:update_thread_list used to call prune_threads, after that change
it doesn't anymore, and we don't implement the to_update_thread_list target
method where the prune_threads call got moved. For now, apply a fix, related
to commit c82f56d9d7 "Hurd: Adjust to
startup-with-shell changes", which restores the previous behavior:
Id Target Id Frame
* 4 Thread 10688.4 main (ac=1, av=0x102cd84) at ../../../W._C._Handy/bfd/doc/chew.c:1535
5 Thread 10688.5 0x0106096c in ?? () from /lib/i386-gnu/libc.so.0.3
Not perfect, but at least better.
gdb/
* gnu-nat.c (gnu_create_inferior): After startup_inferior, call
prune_threads.
Complement commit dd8b7c222e ("MIPS: mips16e jalrc/jrc opcodes"),
<https://sourceware.org/ml/binutils/2005-07/msg00349.html>, and stop the
disassembler making a delay-slot adjustment for PC-relative operations
following either MIPS16e compact jumps, or undefined RR/J(AL)R(C)
encodings that have the `l' (link) and `ra' (source register is `ra')
bits set both at a time. Adjust code description for accuracy. Add a
suitable test case.
opcodes/
* mips-dis.c (print_mips16_insn_arg): Avoid delay-slot
adjustment for PC-relative operations following MIPS16e compact
jumps or undefined RR/J(AL)R(C) encodings.
binutils/
* testsuite/binutils-all/mips/mips16-pcrel.d: New test.
* testsuite/binutils-all/mips/mips16-pcrel.s: New test source.
* testsuite/binutils-all/mips/mips.exp: Run the new test.
Fix a commit a9752fdf83 ("[ARC] Sync cpu names with the ones accepted
by GCC.") build regression:
cc1: warnings being treated as errors
.../gas/config/tc-arc.c: In function 'arc_show_cpu_list':
.../gas/config/tc-arc.c:3452: error: declaration of 'spaces' shadows a global declaration
.../gas/../include/libiberty.h:248: error: shadowed declaration is here
make[4]: *** [tc-arc.o] Error 1
in a way following commit 91d6fa6a03 ("Add -Wshadow to the gcc command
line options used when compiling the binutils.").
gas/
* config/tc-arc.c (arc_show_cpu_list): Rename `spaces' local
variable to `space_buf'.
Fix a commit 008a97eff0 ("[GAS][ARM]Generate unpredictable warning for
pc used in data processing instructions with register-shifted register
operand.") build regression:
cc1: warnings being treated as errors
.../gas/config/tc-arm.c: In function 'encode_arm_shift':
.../gas/config/tc-arm.c:7439: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
make[4]: *** [tc-arm.o] Error 1
in a way following commit 91d6fa6a03 ("Add -Wshadow to the gcc command
line options used when compiling the binutils.").
gas/
* config/tc-arm.c (encode_arm_shift): Rename `index' local
variable to `op_index'.
Fix a commit c2c4ff8d52 ("[AArch64] Add ARMv8.3 FCMLA and FCADD
instructions") build regression:
cc1: warnings being treated as errors
.../opcodes/aarch64-dis.c: In function 'aarch64_ext_sve_addr_rr_lsl':
.../opcodes/aarch64-dis.c:1324: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
make[4]: *** [aarch64-asm.lo] Error 1
in a way following commit 91d6fa6a03 ("Add -Wshadow to the gcc command
line options used when compiling the binutils.").
opcodes/
* aarch64-asm.c (aarch64_ins_reglane): Rename `index' local
variable to `reglane_index'.
I got a report of a gdb crash for vle and further investigation showed an
attempt to disassemble an invalid memory range. I tracked the crash down
to the code in get_powerpc_dialect, where we fail to make sure we have a
valid section pointer before dereferencing it.
There is no such problem for rs6000-based disassembling.
opcodes/ChangeLog:
2016-12-08 Luis Machado <lgustavo@codesourcery.com>
* ppc-dis.c (get_powerpc_dialect): Check NULL info->section.
A branch in a non-exec section that needs a stub can lead to this
assertion.
* powerpc.cc (Powerpc_relobj::stub_table): Return NULL rather
then asserting.
Follow-up to commit 14f6890677.
global_thread_id_to_ptid expects global thread numbers, which are nowadays only
used in MI, never presented to the user in the CLI. Since this is a CLI
command, it should accept the inferior-qualified format instead.
gdb/
* gnu-nat.c (set_sig_thread_cmd): Use parse_thread_id instead of
global_thread_id_to_ptid.
..., so handle these in "C" mode still:
gdb/
* config/i386/i386gnu.mh (%_S.o %_U.o): Add "-x c" to
"COMPILE.post".
* gnu-nat.c: #include Mach/Hurd headers before all others. Wrap
Mach/Hurd headers and MIG stubs' prototypes in 'extern "C"'.
* i386-gnu-nat.c: Likewise.
GNU/Hurd uses its own "typedef enum __error_t_codes error_t;"
([glibc]/sysdeps/mach/hurd/bits/errno.h), contrary to the default
"typedef int error_t;" ([glibc]/stdlib/errno.h).
The Mach/Hurd RPCs return kern_return_t values, for which, upon assigning them
to an error_t variable, GCC in C++ mode tells us "error: invalid conversion
from 'kern_return_t {aka int}' to 'error_t {aka __error_t_codes}'". Instead of
casting all these RPC return values to "error_t", just use "kern_return_t"
variables:
gdb/
* gnu-nat.c (proc_get_exception_port, proc_set_exception_port)
(INF_RESUME_MSGPORT_RPC, proc_get_state, _proc_get_exc_port)
(proc_steal_exc_port, proc_restore_exc_port, make_proc)
(inf_startup, inf_set_pid, inf_validate_procinfo)
(inf_validate_task_sc, inf_set_traced, inf_validate_procs)
(inf_signal, inf_continue, gnu_wait, S_exception_raise_request)
(do_mach_notify_dead_name, S_proc_wait_reply)
(S_msg_sig_post_untraced_reply, S_msg_sig_post_reply)
(port_msgs_queued, gnu_read_inferior, gnu_write_inferior)
(gnu_find_memory_regions, steal_exc_port, thread_takeover_sc_cmd)
(flush_inferior_icache): Instead of "error_t" use "kern_return_t".
* i386-gnu-nat.c (fetch_fpregs, store_fpregs, i386_gnu_dr_get)
(i386_gnu_dr_set): Likewise.
... by a bit of code refactoring:
gdb/
* gnu-nat.c (set_task_pause_cmd, set_signals_cmd)
(set_exceptions_cmd): Add variants taking an "int arg" instead of
a "char *". Make the "char *" variants use the former.
(set_noninvasive_cmd): Also use the "int arg" variants.
C++ doesn't do implicit type conversions from "void *", so we have to...
gdb/
* i386-gnu-nat.c (i386_gnu_dr_set_control_one)
(i386_gnu_dr_set_addr_one): Explicitly cast "void *".
Replace a global `mips_opts.isa' reference in `is_opcode_valid' and use
a local copy just made in `isa'. No functional change.
gas/
* config/tc-mips.c (is_opcode_valid): Use local `isa'
consistently.
Adds a new option, defaulting to off, that allows a group of stubs to
serve multiple output sections. Prior to this patch powerpc gold
allowed this unconditionally, which is a little unsafe with clever
code that discards/reuses sections at runtime.
* options.h (--stub-group-multi): New PowerPC option.
* powerpc.cc (Stub_control): Add multi_os_ var and param
to constructor. Sort start_ var later. Comment State.
(Stub_control::can_add_to_stub_group): Heed multi_os_.
(Target_powerpc::group_sections): Update.
Gold attaches stubs to an existing section in contrast to ld.bfd which
inserts a new section for stubs. If we want stubs before branches,
then the stubs must be added to the previous section. Adding to the
previous section is a disaster if there is a large gap between the
previous section and the group.
PR gold/20878
* powerpc.cc (Stub_control): Replace stubs_always_before_branch_
with stubs_always_after_branch_, group_end_addr_ with
group_start_addr_.
(Stub_control::can_add_to_stub_group): Rewrite to suit scanning
sections by increasing address.
(Target_powerpc::group_sections): Scan that way. Delete corner
case.
* options.h (--stub-group-size): Update help string.
Some more debug output, and a little hardening.
* powerpc.cc (Stub_table_owner): Provide constructor.
(Powerpc_relobj::set_stub_table): Resize fill with -1.
(Target_powerpc::Branch_info::make_stub): Provide target debug
output on returning false.
