ARMv8 supports tagged address, that is, the top one byte in address
is ignored. It is always enabled on aarch64-linux. See
https://www.kernel.org/doc/Documentation/arm64/tagged-pointers.txt
The tag in the tagged address is modeled as non-significant bits in
address, so this patch adds a new gdbarch method significant_addr_bit and
clear the non-significant bits (the top byte in ARMv8) of the virtual
address at the point before passing address to target cache layer. IOW,
the address used in the target cache layer is already cleared.
Before this patch,
(gdb) x/x 0x0000000000411030
0x411030 <global>: 0x00000000
(gdb) x/x 0xf000000000411030
0xf000000000411030: Cannot access memory at address 0xf000000000411030
After this patch,
(gdb) x/x 0x0000000000411030
0x411030 <global>: 0x00000000
(gdb) x/x 0xf000000000411030
0xf000000000411030: 0x00000000
Note that I used address_significant in paddress, but it causes a
regression gdb.base/long_long.exp, because gdb clears the non-significant
bits in address, but test still expects them.
p/a val.oct^M
$24 = 0x2ee53977053977^M
(gdb) FAIL: gdb.base/long_long.exp: p/a val.oct
so I defer the change there.
gdb:
2017-12-08 Yao Qi <yao.qi@linaro.org>
* aarch64-tdep.c (aarch64_gdbarch_init): Install gdbarch
significant_addr_bit.
* gdbarch.sh (significant_addr_bit): New.
* gdbarch.c, gdbarch.h: Re-generated.
* target.c (memory_xfer_partial): Call address_significant.
* utils.c (address_significant): New function.
* utils.h (address_significant): Declare.
2017-12-08 Yao Qi <yao.qi@linaro.org>
gdb/testsuite:
* gdb.arch/aarch64-tagged-pointer.c: New file.
* gdb.arch/aarch64-tagged-pointer.exp: New file.
Revert parts of commit b3ac9c7756 ("Put more info in NT_PRPSINFO Linux
notes"), <https://sourceware.org/ml/binutils/2013-02/msg00024.html>, and
remove support for a Linux core PRPSINFO note writer override, now that
all variants are handled automatically within BFD itself.
gdb/
* linux-tdep.c (linux_make_corefile_notes): Remove call to
`gdbarch_elfcore_write_linux_prpsinfo'.
* gdbarch.sh (elfcore_write_linux_prpsinfo): Remove architecture
method.
(elf_internal_linux_prpsinfo): Remove declaration.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
Remove a duplicate `struct objfile' declaration mistakenly added with
commit 3e29f34a4e ("MIPS: Keep the ISA bit in compressed code
addresses").
gdb/
* gdbarch.sh (objfile): Remove duplicate declaration.
* gdbarch.h: Regenerate.
As an update to commit ede5f15146 ("gdbarch.h: Change
gdbarch_info::tdep_info's type to void *") replace the definition of the
`tdep_info' member in `struct gdbarch_info' with an anonymous union,
comprising the original member, with its type reverted to `struct
gdbarch_tdep_info *', a `tdesc_data' member of a `struct tdesc_arch_data
*' type and an `id' member of an `int *' type. Remove now unnecessary
casts throughout use places then, making code easier to read an less
prone to errors, which may happen with casting.
gdb/
* gdbarch.sh (gdbarch_info): Replace the `tdep_info' member with
a union of `tdep_info', `tdesc_data' and `id'.
* aarch64-tdep.c (aarch64_gdbarch_init): Use `info.tdesc_data'
rather than `info.tdep_info'.
* amd64-linux-tdep.c (amd64_linux_init_abi): Likewise.
* i386-linux-tdep.c (i386_linux_init_abi): Likewise.
* i386-tdep.c (i386_gdbarch_init): Likewise.
* mips-linux-tdep.c (mips_linux_init_abi): Likewise.
* mips-tdep.c (mips_gdbarch_init): Likewise.
* nds32-tdep.c (nds32_gdbarch_init): Likewise.
* rs6000-tdep.c (rs6000_gdbarch_init): Likewise.
* ppc-linux-tdep.c (ppu2spu_sniffer): Use `info.id' rather than
`info.tdep_info'.
(ppc_linux_init_abi): Use `info.tdesc_data' rather than
`info.tdep_info'.
* sparc-tdep.c (sparc32_gdbarch_init): Likewise.
* spu-multiarch.c (spu_gdbarch): Use `info.id' rather than
`info.tdep_info'.
* spu-tdep.c (spu_gdbarch_init): Likewise.
* gdbarch.h: Regenerate.
Previously the core_xfer_partial method used core_get_siginfo to handle
TARGET_OBJECT_SIGNAL_INFO requests. However, core_get_siginfo looked for
Linux-specific sections in the core file. To support fetching siginfo
from cores on other systems, add a new gdbarch method (`core_xfer_siginfo`)
and move the body of the existing core_get_siginfo into a
linux_core_xfer_siginfo implementation of this method in linux-tdep.c.
gdb/ChangeLog:
* corelow.c (get_core_siginfo): Remove.
(core_xfer_partial): Use the gdbarch "core_xfer_siginfo" method
instead of get_core_siginfo.
* gdbarch.sh (core_xfer_siginfo): New gdbarch callback.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
* linux-tdep.c (linux_core_xfer_siginfo): New.
(linux_init_abi): Install gdbarch "core_xfer_siginfo" method.
The displaced_step_free_closure gdbarch hook allows architectures to
free data they might have allocated to complete a displaced step.
However, all architectures using that hook use the
simple_displaced_step_free_closure provided in arch-utils.{c,h}, which
does a simple xfree. We can remove it and do an xfree directly instead
of calling the hook.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_free_closure): Remove.
* gdbarch.h, gdbarch.c: Re-generate.
* aarch64-linux-tdep.c (aarch64_linux_init_abi): Don't set
displaced_step_free_closure.
* amd64-linux-tdep.c (amd64_linux_init_abi_common): Likewise.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* i386-linux-tdep.c (i386_linux_init_abi): Likewise.
* rs6000-aix-tdep.c (rs6000_aix_init_osabi): Likewise.
* rs6000-tdep.c (rs6000_gdbarch_init): Likewise.
* s390-linux-tdep.c (s390_gdbarch_init): Likewise.
* arch-utils.h (simple_displaced_step_free_closure): Remove.
* arch-utils.c (simple_displaced_step_free_closure): Remove.
* infrun.c (displaced_step_clear): Call xfree instead of
gdbarch_displaced_step_free_closure.
As Pedro commented on the patch "Change field separator in gdbarch.sh",
this commented out definition is probably not useful and should be
removed. It has been commented out for basically forever, and it
probably serves the same intent as addressable_memory_unit_size.
gdb/ChangeLog:
* gdbarch.sh: Remove commented out definition of
TARGET_CHAR_BIT.
* gdbarch.h: Re-generate.
The fields in the description of the gdbarch interface are separated
using colons. That becomes a problem if we want to use things like
std::vector in it. This patch changes the field separator to use
semicolons instead.
I think there's very little chance we'll ever want to use a semicolon in
one of the fields, but if you think another character would be more
appropriate, let me know.
gdb/ChangeLog:
* gdbarch.sh: Use semi-colon as field separator instead of colon.
* gdbarch.h: Re-generate.
Recently a feature called "return address signing" has been added to GCC to
prevent stack smash stack on AArch64. For details please refer:
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00376.html
GDB needs to be aware of this feature so it can restore the original return
address which is critical for unwinding.
On compiler side, whenever return address, i.e. LR register, is mangled or
restored by hardware instruction, compiler is expected to generate a
DW_CFA_AARCH64_negate_ra_state to toggle return address signing status.
DW_CFA_AARCH64_negate_ra_state is using the same CFI number and
therefore need to be multiplexed with DW_CFA_GNU_window_save which was designed
for SPARC.
A new gdbarch method "execute_dwarf_cfa_vendor_op" is introduced by this patch.
It's parameters has been restricted to those only needed by SPARC and AArch64
for multiplexing DW_CFA_GNU_window_save which is a CFI operation takes none
operand. Should any further DWARF CFI operation want to be multiplexed in the
future, the parameter list can be extended. Below is the current function
prototype.
typedef int (gdbarch_execute_dwarf_cfa_vendor_op_ftype)
(struct gdbarch *gdbarch, gdb_byte op, struct dwarf2_frame_state *fs);
DW_CFA_GNU_window_save support for SPARC is migrated to this new gdbarch
method by this patch.
gdb/
* gdbarch.sh: New gdbarch method execute_dwarf_cfa_vendor_op.
* gdbarch.c: Regenerated.
* gdbarch.h: Regenerated.
* dwarf2-frame.c (dwarf2_frame_state_alloc_regs): Made the
visibility external.
(execute_cfa_program): Call execute_dwarf_cfa_vendor_op for CFI
between DW_CFA_lo_user and DW_CFA_high_user inclusive.
(enum cfa_how_kind): Move to ...
(struct dwarf2_frame_state_reg_info): Likewise.
(struct dwarf2_frame_state): Likewise.
* dwarf2-frame.h: ... here.
(dwarf2_frame_state_alloc_regs): New declaration.
* sparc-tdep.c (sparc_execute_dwarf_cfa_vendor_op): New function.
(sparc32_gdbarch_init): Register execute_dwarf_cfa_vendor_op hook.
GDB is currently not aware that wchar_t is a built-in type in C++
mode. This is usually not a problem because the debug info describes
the type, so when you have a program loaded, you don't notice this.
However, if you try expressions involving wchar_t before a program is
loaded, gdb errors out:
(gdb) p (wchar_t)-1
No symbol table is loaded. Use the "file" command.
(gdb) p L"hello"
No type named wchar_t.
(gdb) ptype L"hello"
No type named wchar_t.
This commit teaches gdb about the type. After:
(gdb) p (wchar_t)-1
$1 = -1 L'\xffffffff'
(gdb) p L"hello"
$2 = L"hello"
(gdb) ptype L"hello"
type = wchar_t [6]
Unlike char16_t/char32_t, unfortunately, the underlying type of
wchar_t is implementation dependent, both size and signness. So this
requires adding a couple new gdbarch hooks.
I grepped the GCC code base for WCHAR_TYPE and WCHAR_TYPE_SIZE, and it
seems to me that the majority of the ABIs have a 4-byte signed
wchar_t, so that's what I made the default for GDB too. And then I
looked for which ports have a 16-bit and/or unsigned wchar_t, and made
GDB follow suit.
gdb/ChangeLog:
2017-04-12 Pedro Alves <palves@redhat.com>
PR gdb/21323
* c-lang.c (cplus_primitive_types) <cplus_primitive_type_wchar_t>:
New enum value.
(cplus_language_arch_info): Register cplus_primitive_type_wchar_t.
* gdbtypes.h (struct builtin_type) <builtin_wchar>: New field.
* gdbtypes.c (gdbtypes_post_init): Create the "wchar_t" type.
* gdbarch.sh (wchar_bit, wchar_signed): New per-arch values.
* gdbarch.h, gdbarch.c: Regenerate.
* aarch64-tdep.c (aarch64_gdbarch_init): Override
gdbarch_wchar_bit and gdbarch_wchar_signed.
* alpha-tdep.c (alpha_gdbarch_init): Likewise.
* arm-tdep.c (arm_gdbarch_init): Likewise.
* avr-tdep.c (avr_gdbarch_init): Likewise.
* h8300-tdep.c (h8300_gdbarch_init): Likewise.
* i386-nto-tdep.c (i386nto_init_abi): Likewise.
* i386-tdep.c (i386_go32_init_abi): Likewise.
* m32r-tdep.c (m32r_gdbarch_init): Likewise.
* moxie-tdep.c (moxie_gdbarch_init): Likewise.
* nds32-tdep.c (nds32_gdbarch_init): Likewise.
* rs6000-aix-tdep.c (rs6000_aix_init_osabi): Likewise.
* sh-tdep.c (sh_gdbarch_init): Likewise.
* sparc-tdep.c (sparc32_gdbarch_init): Likewise.
* sparc64-tdep.c (sparc64_init_abi): Likewise.
* windows-tdep.c (windows_init_abi): Likewise.
* xstormy16-tdep.c (xstormy16_gdbarch_init): Likewise.
gdb/testsuite/ChangeLog:
2017-04-12 Pedro Alves <palves@redhat.com>
PR gdb/21323
* gdb.cp/wide_char_types.c: Include <wchar.h>.
(wchar): New global.
* gdb.cp/wide_char_types.exp (wide_char_types_program)
(do_test_wide_char, wide_char_types_no_program, top level): Add
wchar_t testing.
This commit adds support to GDB so that it can modify the disassembler-options
value that is passed to the disassembler, similar to objdump's -M option.
Currently, the only supported targets are ARM, PowerPC and S/390, but
adding support for a new target(s) is not difficult.
include/
* dis-asm.h (disasm_options_t): New typedef.
(parse_arm_disassembler_option): Remove prototype.
(set_arm_regname_option): Likewise.
(get_arm_regnames): Likewise.
(get_arm_regname_num_options): Likewise.
(disassemble_init_s390): New prototype.
(disassembler_options_powerpc): Likewise.
(disassembler_options_arm): Likewise.
(disassembler_options_s390): Likewise.
(remove_whitespace_and_extra_commas): Likewise.
(disassembler_options_cmp): Likewise.
(next_disassembler_option): New inline function.
(FOR_EACH_DISASSEMBLER_OPTION): New macro.
opcodes/
* disassemble.c Include "safe-ctype.h".
(disassemble_init_for_target): Handle s390 init.
(remove_whitespace_and_extra_commas): New function.
(disassembler_options_cmp): Likewise.
* arm-dis.c: Include "libiberty.h".
(NUM_ELEM): Delete.
(regnames): Use long disassembler style names.
Add force-thumb and no-force-thumb options.
(NUM_ARM_REGNAMES): Rename from this...
(NUM_ARM_OPTIONS): ...to this. Use ARRAY_SIZE.
(get_arm_regname_num_options): Delete.
(set_arm_regname_option): Likewise.
(get_arm_regnames): Likewise.
(parse_disassembler_options): Likewise.
(parse_arm_disassembler_option): Rename from this...
(parse_arm_disassembler_options): ...to this. Make static.
Use new FOR_EACH_DISASSEMBLER_OPTION macro to scan over options.
(print_insn): Use parse_arm_disassembler_options.
(disassembler_options_arm): New function.
(print_arm_disassembler_options): Handle updated regnames.
* ppc-dis.c: Include "libiberty.h".
(ppc_opts): Add "32" and "64" entries.
(ppc_parse_cpu): Use ARRAY_SIZE and disassembler_options_cmp.
(powerpc_init_dialect): Add break to switch statement.
Use new FOR_EACH_DISASSEMBLER_OPTION macro.
(disassembler_options_powerpc): New function.
(print_ppc_disassembler_options): Use ARRAY_SIZE.
Remove printing of "32" and "64".
* s390-dis.c: Include "libiberty.h".
(init_flag): Remove unneeded variable.
(struct s390_options_t): New structure type.
(options): New structure.
(init_disasm): Rename from this...
(disassemble_init_s390): ...to this. Add initializations for
current_arch_mask and option_use_insn_len_bits_p. Remove init_flag.
(print_insn_s390): Delete call to init_disasm.
(disassembler_options_s390): New function.
(print_s390_disassembler_options): Print using information from
struct 'options'.
* po/opcodes.pot: Regenerate.
binutils/
* objdump.c (main): Use remove_whitespace_and_extra_commas.
gdb/
* NEWS: Mention new set/show disassembler-options commands.
* doc/gdb.texinfo: Document new set/show disassembler-options commands.
* disasm.c: Include "arch-utils.h", "gdbcmd.h" and "safe-ctype.h".
(prospective_options): New static variable.
(gdb_disassembler::gdb_disassembler): Initialize
m_di.disassembler_options.
(gdb_buffered_insn_length_init_dis): Initilize di->disassembler_options.
(get_disassembler_options): New function.
(set_disassembler_options): Likewise.
(set_disassembler_options_sfunc): Likewise.
(show_disassembler_options_sfunc): Likewise.
(disassembler_options_completer): Likewise.
(_initialize_disasm): Likewise.
* disasm.h (get_disassembler_options): New prototype.
(set_disassembler_options): Likewise.
* gdbarch.sh (gdbarch_disassembler_options): New variable.
(gdbarch_verify_disassembler_options): Likewise.
* gdbarch.c: Regenerate.
* gdbarch.h: Likewise.
* arm-tdep.c (num_disassembly_options): Delete.
(set_disassembly_style): Likewise.
(arm_disassembler_options): New static variable.
(set_disassembly_style_sfunc): Convert short style name into long
option name. Call set_disassembler_options.
(show_disassembly_style_sfunc): New function.
(arm_gdbarch_init): Call set_gdbarch_disassembler_options and
set_gdbarch_verify_disassembler_options.
(_initialize_arm_tdep): Delete regnames variable and update callers.
(arm_disassembler_options): Initialize.
(disasm_options): New variable.
(num_disassembly_options): Rename from this...
(num_disassembly_styles): ...to this. Compute by scanning through
disasm_options.
(valid_disassembly_styles): Initialize using disasm_options.
Remove calls to parse_arm_disassembler_option, get_arm_regnames and
set_arm_regname_option.
Pass show_disassembly_style_sfunc to the "disassembler" setshow command.
* rs6000-tdep.c (powerpc_disassembler_options): New static variable.
(rs6000_gdbarch_init): Call set_gdbarch_disassembler_options and
set_gdbarch_verify_disassembler_options.
* s390-tdep.c (s390_disassembler_options): New static variable.
(s390_gdbarch_init):all set_gdbarch_disassembler_options and
set_gdbarch_verify_disassembler_options.
gdb/testsuite/
* gdb.arch/powerpc-power.exp: Delete test.
* gdb.arch/powerpc-power.s: Likewise.
* gdb.disasm/disassembler-options.exp: New test.
* gdb.arch/powerpc-altivec.exp: Likewise.
* gdb.arch/powerpc-altivec.s: Likewise.
* gdb.arch/powerpc-altivec2.exp: Likewise.
* gdb.arch/powerpc-altivec2.s: Likewise.
* gdb.arch/powerpc-altivec3.exp: Likewise.
* gdb.arch/powerpc-altivec3.s: Likewise.
* gdb.arch/powerpc-power7.exp: Likewise.
* gdb.arch/powerpc-power7.s: Likewise.
* gdb.arch/powerpc-power8.exp: Likewise.
* gdb.arch/powerpc-power8.s: Likewise.
* gdb.arch/powerpc-power9.exp: Likewise.
* gdb.arch/powerpc-power9.s: Likewise.
* gdb.arch/powerpc-vsx.exp: Likewise.
* gdb.arch/powerpc-vsx.s: Likewise.
* gdb.arch/powerpc-vsx2.exp: Likewise.
* gdb.arch/powerpc-vsx2.s: Likewise.
* gdb.arch/powerpc-vsx3.exp: Likewise.
* gdb.arch/powerpc-vsx3.s: Likewise.
* gdb.arch/arm-disassembler-options.exp: Likewise.
* gdb.arch/powerpc-disassembler-options.exp: Likewise.
* gdb.arch/s390-disassembler-options.exp: Likewise.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This patch adds a new gdbarch method breakpoint_kind_from_current_state
for single step breakpoint, and uses it in breakpoint_kind.
gdb:
2016-11-03 Yao Qi <yao.qi@linaro.org>
* arch-utils.c (default_breakpoint_kind_from_current_state):
New function.
* arch-utils.h (default_breakpoint_kind_from_current_state):
Declare.
* arm-tdep.c (arm_breakpoint_kind_from_current_state): New
function.
(arm_gdbarch_init): Call
set_gdbarch_breakpoint_kind_from_current_state.
* breakpoint.c (breakpoint_kind): Call
gdbarch_breakpoint_kind_from_current_state for single step
breakpoint. Update comments.
* gdbarch.sh (breakpoint_kind_from_current_state): New.
* gdbarch.c, gdbarch.h: Regenerate.
This patch adds two gdbarch methods breakpoint_kind_from_pc and
sw_breakpoint_from_kind, and uses target_info.placed_size as "kind"
of the breakpoint. This patch updates the usages of
target_info.placed_size.
The "kind" of a breakpoint is determined by gdbarch rather than
target, so we have gdbarch method breakpoint_kind_from_pc, and we
should set target_info.placed_size out of each implementation of
target to_insert_breakpoint. In this way, each target doesn't have
to set target_info.placed_size any more.
This patch also sets target_info.placed_address before
target_insert_breakpoint too, so that target to_insert_breakpoint
can use it, see record_full_insert_breakpoint.
Before we call target_insert_breakpoint, we set
target_info.placed_address and target_info.placed_size like this,
CORE_ADDR addr = bl->target_info.reqstd_address;
bl->target_info.placed_size = gdbarch_breakpoint_kind_from_pc (bl->gdbarch, &addr);
bl->target_info.placed_address = addr;
return target_insert_breakpoint (bl->gdbarch, &bl->target_info);
target_insert_breakpoint may fail, but it doesn't matter to the "kind"
and "placed_address" of a breakpoint. They should be determined by
gdbarch.
gdb:
2016-11-03 Yao Qi <yao.qi@linaro.org>
* arch-utils.h (GDBARCH_BREAKPOINT_MANIPULATION): Define
breakpoint_kind_from_pc and sw_breakpoint_from_kind.
(GDBARCH_BREAKPOINT_MANIPULATION_ENDIAN): Likewise.
(SET_GDBARCH_BREAKPOINT_MANIPULATION): Call
set_gdbarch_breakpoint_kind_from_pc and
set_gdbarch_sw_breakpoint_from_kind.
* arm-tdep.c: Add comments.
* bfin-tdep.c: Likewise.
* breakpoint.c (breakpoint_kind): New function.
(insert_bp_location): Set target_info.placed_size and
target_info.placed_address.
(bkpt_insert_location): Likewise.
* cris-tdep.c: Add comments.
* gdbarch.sh (breakpoint_kind_from_pc): New.
(sw_breakpoint_from_kind): New.
* gdbarch.c, gdbarch.h: Regenerated.
* ia64-tdep.c (ia64_memory_insert_breakpoint): Don't set
bp_tgt->placed_size.
(ia64_memory_remove_breakpoint): Don't assert
bp_tgt->placed_size.
(ia64_breakpoint_kind_from_pc): New function.
(ia64_gdbarch_init): Install ia64_breakpoint_kind_from_pc.
* m32r-tdep.c (m32r_memory_insert_breakpoint): Don't set
bp_tgt->placed_size.
* mem-break.c (default_memory_insert_breakpoint): Don't set
bp_tgt->placed_size. Call gdbarch_sw_breakpoint_from_kind.
(default_memory_remove_breakpoint): Call
gdbarch_sw_breakpoint_from_kind.
(memory_validate_breakpoint): Don't check bp_tgt->placed_size.
* mips-tdep.c: Add comments.
* mt-tdep.c: Likewise.
* nios2-tdep.c: Likewise.
* record-full.c (record_full_insert_breakpoint): Don't call
gdbarch_breakpoint_from_pc. Don't set bp_tgt->placed_address
and bp_tgt->placed_size.
* remote.c (remote_insert_breakpoint): Don't call
gdbarch_remote_breakpoint_from_pc. Use bp_tgt->placed_size.
Don't set bp_tgt->placed_address and bp_tgt->placed_size.
(remote_insert_hw_breakpoint): Likewise.
* score-tdep.c: Likewise.
* sh-tdep.c: Likewise.
* tic6x-tdep.c: Likewise.
* v850-tdep.c: Likewise.
* xtensa-tdep.c: Likewise.
At this point, all TYPE_CODE_FLT types carry their floating-point format,
except for those creating from reading DWARF or stabs debug info. Those
will be addressed by this commit.
The main issue here is that we actually have to determine which floating-
point format to use. Currently, we only have the type length as input
to this decision. In the future, we may hopefully get --at least in
DWARF-- additional information to help disambiguate multiple different
formats of the same length. For now, we can still look at the type name
as a hint.
This decision logic is encapsulated in a gdbarch callback to allow
platform-specific overrides. The default implementation use the same
logic (compare type length against the various gdbarch_..._bit sizes)
that is currently implemented in floatformat_from_length.
With this commit, all platforms still use the default logic, so there
should be no actual change in behavior. A follow-on commit will add
support for __float128 on Intel and Power.
Once dwarf2read.c and stabsread.c make use of the new callback to
determine floating-point formats, we're now sure every TYPE_CODE_FLT
type will always carry its format. The commit therefore adds asserts
to verify_floatformat to ensure new code will continue to always
provide formats, and removes the code in floatformat_from_type that
used to handle types with a NULL TYPE_FLOATFORMAT.
gdb/ChangeLog:
* gdbarch.sh (floatformat_for_type): New gdbarch callback.
* gdbarch.h, gdbarch.c: Re-generate.
* arch-utils.h (default_floatformat_for_type): New prototype.
* arch-utils.c (default_floatformat_for_type): New function.
* doublest.c (floatformat_from_length): Remove.
(floatformat_from_type): Assume TYPE_FLOATFORMAT is non-NULL.
* gdbtypes.c (verify_floatformat): Require non-NULL format.
* dwarf2read.c (dwarf2_init_float_type): New function.
(read_base_type): Use it.
* stabsread.c (dbx_init_float_type): New function.
(read_sun_floating_type): Use it.
(read_range_type): Likewise.
Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Different platforms have different meanings for auxiliary vector
entries. The 'print_auxv_entry' gdbarch method allows an architecture
to output a suitable description for platform-specific entries.
A fprint_auxv_entry function is split out of fprint_target_auxv.
This function outputs the description of a single auxiliary vector
entry to the specified file using caller-supplied formatting and
strings to describe the vector type.
The existing switch on auxiliary vector types is moved out of
fprint_target_auxv into a new default_print_auxv_entry function.
default_print_auxv_entry chooses an appropriate format and description
and calls fprint_single_auxv to describe a single vector entry.
This function is used as the default 'print_auxv_entry' gdbarch method.
fprint_target_auxv now invokes the gdbarch 'print_auxv_entry' method
on each vector entry.
gdb/ChangeLog:
* auxv.c (fprint_auxv_entry): New function.
(default_print_auxv_entry): New function.
(fprint_target_auxv): Use gdbarch_print_auxv_entry.
* auxv.h (enum auxv_format): New enum.
(fprint_auxv_entry): Declare.
(default_print_auxv_entry): Declare.
* gdbarch.sh (print_auxv_entry): New.
* gdbarch.c, gdbarch.h: Re-generated.
Nowadays, GDB can't insert breakpoint on the return address of the
exception handler on ARM M-profile, because the address is a magic
one 0xfffffff9,
(gdb) bt
#0 CT32B1_IRQHandler () at ../src/timer.c:67
#1 <signal handler called>
#2 main () at ../src/timer.c:127
(gdb) info frame
Stack level 0, frame at 0x200ffa8:
pc = 0x4ec in CT32B1_IRQHandler (../src/timer.c:67); saved pc = 0xfffffff9
called by frame at 0x200ffc8
source language c.
Arglist at 0x200ffa0, args:
Locals at 0x200ffa0, Previous frame's sp is 0x200ffa8
Saved registers:
r7 at 0x200ffa0, lr at 0x200ffa4
(gdb) x/x 0xfffffff9
0xfffffff9: Cannot access memory at address 0xfffffff9
(gdb) finish
Run till exit from #0 CT32B1_IRQHandler () at ../src/timer.c:67
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 0.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
even some debug probe can't set hardware breakpoint on the magic
address too,
(gdb) hbreak *0xfffffff9
Hardware assisted breakpoint 2 at 0xfffffff9
(gdb) c
Continuing.
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 2.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
The problem described above is quite similar to PR 8841, in which GDB
can't set breakpoint on signal trampoline, which is mapped to a read-only
page by kernel. The rationale of this patch is to skip "unwritable"
frames when looking for caller frames in command "finish", and a new
gdbarch method code_of_frame_writable is added. This patch fixes
the problem on ARM cortex-m target, but it can be used to fix
PR 8841 too.
gdb:
2016-05-10 Yao Qi <yao.qi@arm.com>
* arch-utils.c (default_code_of_frame_writable): New function.
* arch-utils.h (default_code_of_frame_writable): Declare.
* arm-tdep.c (arm_code_of_frame_writable): New function.
(arm_gdbarch_init): Install gdbarch method
code_of_frame_writable if the target is M-profile.
* frame.c (skip_unwritable_frames): New function.
* frame.h (skip_unwritable_frames): Declare.
* gdbarch.sh (code_of_frame_writable): New.
* gdbarch.c, gdbarch.h: Re-generated.
* infcmd.c (finish_command): Call skip_unwritable_frames.
GDB doesn't insert software single step breakpoint if the instruction
branches to itself, so that the program can't stop after command "si".
(gdb) b 32
Breakpoint 2 at 0x8680: file git/gdb/testsuite/gdb.base/branch-to-self.c, line 32.
(gdb) c
Continuing.
Breakpoint 2, main () at gdb/git/gdb/testsuite/gdb.base/branch-to-self.c:32
32 asm (".Lhere: " BRANCH_INSN " .Lhere"); /* loop-line */
(gdb) si
infrun: clear_proceed_status_thread (Thread 3991.3991)
infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: step-over queue now empty
infrun: resuming [Thread 3991.3991] for step-over
infrun: skipping breakpoint: stepping past insn at: 0x8680
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending packet: $Z0,8678,4#f3...Packet received: OK
infrun: skipping breakpoint: stepping past insn at: 0x8680
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending packet: $Z0,b6fe86c8,4#82...Packet received: OK
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 3991.3991] at 0x868
breakpoint.c:should_be_inserted thinks the breakpoint shouldn't be
inserted, which is wrong. This patch restrict the condition that
only skip the non-single-step breakpoints if they are inserted at
the place we are stepping over, however we don't want to skip
single-step breakpoint if its thread is the thread we are stepping
over, so in this patch, I add a thread num in 'struct step_over_info'
to record the thread we're stepping over.
gdb:
2016-04-25 Yao Qi <yao.qi@linaro.org>
* breakpoint.c (should_be_inserted): Return 0 if the location's
owner is not single step breakpoint or single step breakpoint's
thread isn't the thread which is stepping past a breakpoint.
* gdbarch.sh (software_single_step): Update comments.
* gdbarch.h: Regenerated.
* infrun.c (struct step_over_info) <thread>: New field.
(set_step_over_info): New argument 'thread'. Callers updated.
(clear_step_over_info): Set field thread to -1.
(thread_is_stepping_over_breakpoint): New function.
* infrun.h (thread_is_stepping_over_breakpoint): Declaration.
This comment is out of date. We've already done that. Patch is to remove
it.
gdb:
2016-03-23 Yao Qi <yao.qi@linaro.org>
* gdbarch.sh (software_single_step): Remove comments.
* gdbarch.h: Regenerated.
With Intel Memory Protection Extensions it was introduced the concept of
boundary violation. A boundary violations is presented to the inferior as
a segmentation fault having SIGCODE 3. This patch adds a
handler for a boundary violation extending the information displayed
when a bound violation is presented to the inferior. In the stop mode
case the debugger will also display the kind of violation: "upper" or
"lower", bounds and the address accessed.
On no stop mode the information will still remain unchanged. Additional
information about bound violations are not meaningful in that case user
does not know the line in which violation occurred as well.
When the segmentation fault handler is stop mode the out puts will be
changed as exemplified below.
The usual output of a segfault is:
Program received signal SIGSEGV, Segmentation fault
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In case it is a bound violation it will be presented as:
Program received signal SIGSEGV, Segmentation fault
Upper bound violation while accessing address 0x7fffffffc3b3
Bounds: [lower = 0x7fffffffc390, upper = 0x7fffffffc3a3]
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In mi mode the output of a segfault is:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault", frame={addr="0x0000000000400d7c",
func="upper",args=[{name="p", value="0x603010"},{name="a",value="0x603030"}
,{name="b",value="0x603050"}, {name="c",value="0x603070"},
{name="d",value="0x603090"},{name="len",value="7"}],
file="i386-mpx-sigsegv.c",fullname="i386-mpx-sigsegv.c",line="68"},
thread-id="1",stopped-threads="all",core="6"
in the case of a bound violation:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault",
sigcode-meaning="Upper bound violation",
lower-bound="0x603010",upper-bound="0x603023",bound-access="0x60302f",
frame={addr="0x0000000000400d7c",func="upper",args=[{name="p",
value="0x603010"},{name="a",value="0x603030"},{name="b",value="0x603050"},
{name="c",value="0x603070"},{name="d",value="0x603090"},
{name="len",value="7"}],file="i386-mpx-sigsegv.c",
fullname="i386-mpx-sigsegv.c",line="68"},thread-id="1",
stopped-threads="all",core="6"
2016-02-18 Walfred Tedeschi <walfred.tedeschi@intel.com>
gdb/ChangeLog:
* NEWS: Add entry for bound violation.
* amd64-linux-tdep.c (amd64_linux_init_abi_common):
Add handler for segmentation fault.
* gdbarch.sh (handle_segmentation_fault): New.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* i386-linux-tdep.c (i386_linux_handle_segmentation_fault): New.
(SIG_CODE_BONDARY_FAULT): New define.
(i386_linux_init_abi): Use i386_mpx_bound_violation_handler.
* i386-linux-tdep.h (i386_linux_handle_segmentation_fault) New.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* infrun.c (handle_segmentation_fault): New function.
(print_signal_received_reason): Use handle_segmentation_fault.
gdb/testsuite/ChangeLog:
* gdb.arch/i386-mpx-sigsegv.c: New file.
* gdb.arch/i386-mpx-sigsegv.exp: New file.
* gdb.arch/i386-mpx-simple_segv.c: New file.
* gdb.arch/i386-mpx-simple_segv.exp: New file.
gdb/doc/ChangeLog:
* gdb.texinfo (Signals): Add bound violation display hints for
a SIGSEGV.
When we're looking at a tracefile trace frame where registers are not
available, and the tracepoint has only one location, we supply
the location's address as the PC register. However, this only works
if PC is not a pseudo register, and individual architectures may want
to guess more registers. Add a gdbarch hook that will handle that.
gdb/ChangeLog:
* arch-utils.c (default_guess_tracepoint_registers): New function.
* arch-utils.h (default_guess_tracepoint_registers): New prototype.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh: Add guess_tracepoint_registers hook.
* tracefile.c (tracefile_fetch_registers): Use the new gdbarch hook.
Add a new gdbarch method to extract a thread name from a core for a
given thread. Use this new method in core_thread_name to implement the
to_thread_name target op.
gdb/ChangeLog:
* corelow.c (core_thread_name): New function.
(init_core_ops): Use "core_thread_name" for the "to_thread_name"
target op.
* gdbarch.sh (core_thread_name): New gdbarch callback.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
As reported by Ulrich here:
https://sourceware.org/ml/gdb-patches/2015-09/msg00604.html
The system compiler (gcc 4.1) in Centos 5 doesn't like that we cast to a
pointer to a type that doesn't exist. I see no real value in using this
kind iof construct over just using void *. So this patch changes the
tdep_info field to void * and removes the casts. Even in C++, we
should not need an explicit cast when assigning to a void *.
gdb/ChangeLog:
* gdbarch.sh (struct gdbarch_info): Change tdep_info's type to void *.
* gdbarch.h: Regenerate.
* i386-tdep.c (i386_gdbarch_init): Remove cast to
struct gdbarch_tdep_info *.
* mips-tdep.c (mips_gdbarch_init): Likewise.
* ppc-linux-tdep (ppu2spu_sniffer): Likewise.
* rs6000-tdep.c (rs6000_gdbarch_init): Likewise.
* spu-multiarch.c (spu_gdbarch): Likewise.
Since the type whose name is being set is now being allocated on the
gdbarch obstack, we should allocate its TYPE_NAME on the obstack too.
This reduces the number of individual valgrind warnings for the command
"gdb gdb" from ~300 to ~150.
Tested on x86_64-unknown-linux-gnu.
gdb/ChangeLog:
* gdb_obstack.h (obstack_strdup): Declare.
* gdb_obstack.c (obstack_strdup): Define.
* gdbarch.sh (gdbarch_obstack_strdup): Declare and define.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbtypes.c (arch_type): Use gdbarch_obstack_strdup.
Since the type whose name is being set is now being allocated on the
gdbarch obstack, we should allocate its TYPE_NAME on the obstack too.
This reduces the number of individual valgrind warnings for the command
"gdb gdb" from ~300 to ~150.
Tested on x86_64-unknown-linux-gnu.
gdb/ChangeLog:
* gdbarch.h (gdbarch_obstack_strdup): Declare.
* gdbarch.c (gdbarch_obstack_strdup): Define.
* gdbtypes.c (arch_type): Use it.
The ppc64 displaced step code can't handle atomic sequences. Fallback
to stepping over the breakpoint in-line if we detect one.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (displaced_step_prepare_throw): Return -1 if
gdbarch_displaced_step_copy_insn returns NULL. Update intro
comment.
* rs6000-tdep.c (LWARX_MASK, LWARX_INSTRUCTION, LDARX_INSTRUCTION)
(STWCX_MASK, STWCX_INSTRUCTION, STDCX_INSTRUCTION): Move higher up
in file.
(ppc_displaced_step_copy_insn): New function.
(ppc_displaced_step_fixup): Update comment.
(rs6000_gdbarch_init): Install ppc_displaced_step_copy_insn as
gdbarch_displaced_step_copy_insn hook.
* gdbarch.sh (displaced_step_copy_insn): Document what happens on
NULL return.
* gdbarch.h: Regenerate.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.arch/ppc64-atomic-inst.exp (do_test): New procedure, move
tests here.
(top level): Run do_test with and without displaced stepping.
This patch removes the isize output argument from the
fast_tracepoint_valid_at gdbarch hook. It was used to return the size
of the instruction that needs to be replaced when installing a fast
tracepoint. Instead of getting this value from the
fast_tracepoint_valid_at hook, we can call the gdb_insn_length function.
If we do not do this, then architectures which do not have a restriction
on where to install the fast tracepoint will send uninitialized memory
off to GDBserver. See remote_download_tracepoint:
~~~
int isize;
if (gdbarch_fast_tracepoint_valid_at (target_gdbarch (),
tpaddr, &isize, NULL))
xsnprintf (buf + strlen (buf), BUF_SIZE - strlen (buf), ":F%x",
isize);
~~~
The default implementation of fast_tracepoint_valid_at will not set
isize resulting in uninitialized memory being sent. Later on, GDBserver
could use this information to compute a jump offset.
gdb/ChangeLog:
* arch-utils.c (default_fast_tracepoint_valid_at): Remove unused
isize argument.
* arch-utils.h (default_fast_tracepoint_valid_at): Likewise.
* breakpoint.c (check_fast_tracepoint_sals): Adjust call to
gdbarch_fast_tracepoint_valid_at.
* gdbarch.sh (fast_tracepoint_valid_at): Remove isize argument.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
* i386-tdep.c (i386_fast_tracepoint_valid_at): Remove isize
argument. Do not set it.
* remote.c (remote_download_tracepoint): Adjust call to
gdbarch_fast_tracepoint_valid_at. Call gdb_insn_length to get
the instruction length.
Add a new gdbarch method to get the length of an addressable memory unit
for a given architecture. The default implementation returns 1.
gdb/ChangeLog:
* arch-utils.h (default_addressable_memory_unit_size): New.
* arch-utils.c (default_addressable_memory_unit_size): New.
* gdbarch.sh (addressable_memory_unit_size): New.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
Currently inferior memory is allocated by inferior mmap() but it is never
deallocated; despite the injected objfile incl. its symbols is freed. This was
intentional so that one can do for example:
inferior:
char *str = "foo";
GDB:
(gdb) compile code str = "bar";
I believe later patches will be needed to introduce full control over keeping
vs. discarding the injected module as being discussed in:
compile: objfiles lifetime UI
https://sourceware.org/ml/gdb/2015-04/msg00051.html
Message-ID: <20150429135735.GA16974@host1.jankratochvil.net>
https://sourceware.org/ml/gdb/2015-05/msg00007.html
As decided by Phil it is better not to leak inferior pages as users can
workaround the issue above for example by:
(gdb) compile code str = strdup ("bar");
I have checked that in fact gdb/doc/ (written by Phil) already expects the
injected code will be unmapped so that does not need to be changed:
compile code int ff = 5; p = &ff;
In this example, @code{p} would point to @code{ff} when the
@code{compile} command is executing the source code provided to it.
However, as variables in the (example) program persist with their
assigned values, the variable @code{p} would point to an invalid
location when the command exists.
gdb/ChangeLog
2015-04-28 Jan Kratochvil <jan.kratochvil@redhat.com>
* arch-utils.c (default_infcall_munmap): New.
* arch-utils.h (default_infcall_munmap): New declaration.
* compile/compile-object-load.c (struct munmap_list, munmap_list_add)
(munmap_list_free, munmap_listp_free_cleanup): New.
(struct setup_sections_data): Add field munmap_list_headp.
(setup_sections): Call munmap_list_add.
(compile_object_load): New variable munmap_list_head, initialize
setup_sections_data.munmap_list_headp, return munmap_list_head.
* compile/compile-object-load.h (struct munmap_list): New declaration.
(struct compile_module): Add field munmap_list_head.
(munmap_list_free): New declaration.
* compile/compile-object-run.c (struct do_module_cleanup): Add field
munmap_list_head.
(do_module_cleanup): Call munmap_list_free.
(compile_object_run): Pass munmap_list_head to do_module_cleanup.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (infcall_munmap): New.
* linux-tdep.c (linux_infcall_munmap): New.
(linux_init_abi): Install it.
gdb/testsuite/ChangeLog
2015-04-28 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.compile/compile.exp (keep jit in memory): Rename to ...
(do not keep jit in memory): ... this.
(expect 5): Change it to ...
(expect no 5): ... this.
We concluded that gdbarch_in_function_epilogue_p is misnamed, since it
returns true if the given PC is one instruction after the one that
destroyed the stack (which isn't necessarily inside an epilogue),
therefore it should be renamed to stack_frame_destroyed_p.
I also took the liberty of renaming the arch-specific implementations to
*_stack_frame_destroyed_p as well for consistency.
gdb:
2015-05-26 Martin Galvan <martin.galvan@tallertechnologies.com>
* amd64-tdep.c: Replace in_function_epilogue_p with
stack_frame_destroyed_p throughout.
* arch-utils.c: Ditto.
* arch-utils.h: Ditto.
* arm-tdep.c: Ditto.
* breakpoint.c: Ditto.
* gdbarch.sh: Ditto.
* hppa-tdep.c: Ditto.
* i386-tdep.c: Ditto.
* mips-tdep.c: Ditto.
* nios2-tdep.c: Ditto.
* rs6000-tdep.c: Ditto.
* s390-linux-tdep.c: Ditto.
* score-tdep.c: Ditto.
* sh-tdep.c: Ditto.
* sparc-tdep.c: Ditto.
* sparc-tdep.h: Ditto.
* sparc64-tdep.c: Ditto.
* spu-tdep.c: Ditto.
* tic6x-tdep.c: Ditto.
* tilegx-tdep.c: Ditto.
* xstormy16-tdep.c: Ditto.
* gdbarch.c, gdbarch.h: Re-generated.
Building GDB in C++ mode, I got:
src/gdb/gdbarch.h:240:149: error: invalid type in declaration before ‘;’ token
src/gdb/gdbarch.h:240:14: error: use of enum ‘register_status’ without previous declaration
src/gdb/gdbarch.h:241:13: error: use of enum ‘register_status’ without previous declaration
src/gdb/gdbarch.h:241:140: error: invalid type in declaration before ‘;’ token
That's because 'enum register_status' has not been declared (and we can't
forward declare enums in C++).
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* gdbarch.sh: Include regcache.h.
* gdbarch.h: Regenerate.
This patch adds several gdbarch functions (along with the corresponding
predicates): `dtrace_parse_probe_argument', `dtrace_probe_is_enabled',
`dtrace_enable_probe' and `dtrace_disable_probe'. These functions will
be implemented by target-specific code, and called from the DTrace
probes implementation in order to calculate the value of probe
arguments, and manipulate is-enabled probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdbarch.sh (dtrace_parse_probe_argument): New.
(dtrace_probe_is_enabled): Likewise.
(dtrace_enable_probe): Likewise.
(dtrace_disable_probe): Likewise.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
As reported in PR 17808, a test case with a forged (invalid) core file
can crash GDB with an assertion failure. In that particular case the
prstatus of an i386 core file looks like that from an AMD64 core file.
Consequently the respective regset supply function i386_supply_gregset
is invoked with a larger buffer than usual. But i386_supply_gregset
asserts a specific buffer size, and this assertion fails.
The patch relaxes all buffer size assertions in regset supply
functions such that they merely check for a sufficiently large buffer.
For consistency the regset collect functions are adjusted as well.
gdb/ChangeLog:
PR corefiles/17808:
* gdbarch.sh (iterate_over_regset_sections_cb): Document this
function type, particularly its SIZE parameter.
* gdbarch.h: Regenerate.
* amd64-tdep.c (amd64_supply_fpregset): In gdb_assert, compare
actual against required size using ">=" instead of "==".
(amd64_collect_fpregset): Likewise.
* i386-tdep.c (i386_supply_gregset): Likewise.
(i386_collect_gregset): Likewise.
(i386_supply_fpregset): Likewise.
(i386_collect_fpregset): Likewise.
* mips-linux-tdep.c (mips_supply_gregset_wrapper): Likewise.
(mips_fill_gregset_wrapper): Likewise.
(mips_supply_fpregset_wrapper): Likewise.
(mips_fill_fpregset_wrapper): Likewise.
(mips64_supply_gregset_wrapper): Likewise.
(mips64_fill_gregset_wrapper): Likewise.
(mips64_supply_fpregset_wrapper): Likewise.
(mips64_fill_fpregset_wrapper): Likewise.
* mn10300-linux-tdep.c (am33_supply_gregset_method): Likewise.
(am33_supply_fpregset_method): Likewise.
(am33_collect_gregset_method): Likewise.
(am33_collect_fpregset_method): Likewise.
This patch is to change print_float_info gdbarch method for the
following two reasons,
1. we want to add a default implementation of print_float_info to
dump the float pointer registers. It can be reused by backend to
print something more than float point registers.
2. we want to simplify the caller of print_float_info,
infcmd.c:print_float_info.
gdb:
2014-12-18 Yao Qi <yao@codesourcery.com>
* gdbarch.sh (print_float_info): Change its type from 'M' to 'm'.
* gdbarch.c: Re-generated.
* gdbarch.h: Likewise.
* infcmd.c (default_print_float_info): New function.
(print_float_info): Removed. Move code to
default_print_float_info.
(float_info): Adjust to call gdbarch_print_float_info.
* inferior.h (default_print_float_info): Declare it.
gdb has to inform libcc1.so of the target being used, so that the
correct compiler can be invoked. The compiler is invoked using the
GNU configury triplet prefix, e.g., "x86_64-unknown-linux-gnu-gcc".
In order for this to work we need to map the gdbarch to the GNU
configury triplet arch. In most cases these are identical; however,
the x86 family poses some problems, as the BFD arch names are quite
different from the GNU triplet names. So, we introduce a new gdbarch
method for this. A regular expression is used because there are
various valid values for the arch prefix in the triplet.
This patch also updates the osabi code to associate a regular
expression with the OS ABI. I have only added a concrete value for
Linux. Note that the "-gnu" part is optional, at least on Fedora it
is omitted from the installed GCC executable's name.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* osabi.h (osabi_triplet_regexp): Declare.
* osabi.c (struct osabi_names): New.
(gdb_osabi_names): Change type to struct osabi_names. Update
values.
(gdbarch_osabi_name): Update.
(osabi_triplet_regexp): New function.
(osabi_from_tdesc_string, _initialize_gdb_osabi): Update.
* i386-tdep.c (i386_gnu_triplet_regexp): New method.
(i386_elf_init_abi, i386_go32_init_abi, i386_gdbarch_init): Call
set_gdbarch_gnu_triplet_regexp.
* gdbarch.sh (gnu_triplet_regexp): New method.
* gdbarch.c, gdbarch.h: Rebuild.
* arch-utils.h (default_gnu_triplet_regexp): Declare.
* arch-utils.c (default_gnu_triplet_regexp): New function.
The compiler needed two new gdbarch methods.
The infcall_mmap method allocates memory in the inferior.
This is used when inserting the object code.
The gcc_target_options method computes some arch-specific gcc options
to pass to the compiler. This is used to ensure that gcc generates
object code for the correct architecture.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* arch-utils.c (default_infcall_mmap)
(default_gcc_target_options): New functions.
* arch-utils.h (GDB_MMAP_PROT_READ, GDB_MMAP_PROT_WRITE)
(GDB_MMAP_PROT_EXEC): Define.
(default_infcall_mmap, default_gcc_target_options): Declare.
* gdbarch.h: Rebuild.
* gdbarch.c: Rebuild.
* gdbarch.sh (infcall_mmap, gcc_target_options): New methods.
1. Background information
The MIPS architecture, as originally designed and implemented in
mid-1980s has a uniform instruction word size that is 4 bytes, naturally
aligned. As such all MIPS instructions are located at addresses that
have their bits #1 and #0 set to zeroes, and any attempt to execute an
instruction from an address that has any of the two bits set to one
causes an address error exception. This may for example happen when a
jump-register instruction is executed whose register value used as the
jump target has any of these bits set.
Then in mid 1990s LSI sought a way to improve code density for their
TinyRISC family of MIPS cores and invented an alternatively encoded
instruction set in a joint effort with MIPS Technologies (then a
subsidiary of SGI). The new instruction set has been named the MIPS16
ASE (Application-Specific Extension) and uses a variable instruction
word size, which is 2 bytes (as the name of the ASE suggests) for most,
but there are a couple of exceptions that take 4 bytes, and then most of
the 2-byte instructions can be treated with a 2-byte extension prefix to
expand the range of the immediate operands used.
As a result instructions are no longer 4-byte aligned, instead they are
aligned to a multiple of 2. That left the bit #0 still unused for code
references, be it for the standard MIPS (i.e. as originally invented) or
for the MIPS16 instruction set, and based on that observation a clever
trick was invented that on one hand allowed the processor to be
seamlessly switched between the two instruction sets at any time at the
run time while on the other avoided the introduction of any special
control register to do that.
So it is the bit #0 of the instruction address that was chosen as the
selector and named the ISA bit. Any instruction executed at an even
address is interpreted as a standard MIPS instruction (the address still
has to have its bit #1 clear), any instruction executed at an odd
address is interpreted as a MIPS16 instruction.
To switch between modes ordinary jump instructions are used, such as
used for function calls and returns, specifically the bit #0 of the
source register used in jump-register instructions selects the execution
(ISA) mode for the following piece of code to be interpreted in.
Additionally new jump-immediate instructions were added that flipped the
ISA bit to select the opposite mode upon execution. They were
considered necessary to avoid the need to make register jumps in all
cases as the original jump-immediate instructions provided no way to
change the bit #0 at all.
This was all important for cases where standard MIPS and MIPS16 code had
to be mixed, either for compatibility with the existing binary code base
or to access resources not reachable from MIPS16 code (the MIPS16
instruction set only provides access to general-purpose registers, and
not for example floating-point unit registers or privileged coprocessor
0 registers) -- pieces of code in the opposite mode can be executed as
ordinary subroutine calls.
A similar approach has been more recently adopted for the MIPS16
replacement instruction set defined as the so called microMIPS ASE.
This is another instruction set encoding introduced to the MIPS
architecture. Just like the MIPS16 ASE, the microMIPS instruction set
uses a variable-length encoding, where each instruction takes a multiple
of 2 bytes. The ISA bit has been reused and for microMIPS-capable
processors selects between the standard MIPS and the microMIPS mode
instead.
2. Statement of the problem
To put it shortly, MIPS16 and microMIPS code pointers used by GDB are
different to these observed at the run time. This results in the same
expressions being evaluated producing different results in GDB and in
the program being debugged. Obviously it's the results obtained at the
run time that are correct (they define how the program behaves) and
therefore by definition the results obtained in GDB are incorrect.
A bit longer description will record that obviously at the run time the
ISA bit has to be set correctly (refer to background information above
if unsure why so) or the program will not run as expected. This is
recorded in all the executable file structures used at the run time: the
dynamic symbol table (but not always the static one!), the GOT, and
obviously in all the addresses embedded in code or data of the program
itself, calculated by applying the appropriate relocations at the static
link time.
While a program is being processed by GDB, the ISA bit is stripped off
from any code addresses, presumably to make them the same as the
respective raw memory byte address used by the processor to access the
instruction in the instruction fetch access cycle. This stripping is
actually performed outside GDB proper, in BFD, specifically
_bfd_mips_elf_symbol_processing (elfxx-mips.c, see the piece of code at
the very bottom of that function, starting with an: "If this is an
odd-valued function symbol, assume it's a MIPS16 or microMIPS one."
comment).
This function is also responsible for symbol table dumps made by
`objdump' too, so you'll never see the ISA bit reported there by that
tool, you need to use `readelf'.
This is however unlike what is ever done at the run time, the ISA bit
once present is never stripped off, for example a cast like this:
(short *) main
will not strip the ISA bit off and if the resulting pointer is intended
to be used to access instructions as data, for example for software
instruction decoding (like for fault recovery or emulation in a signal
handler) or for self-modifying code then the bit still has to be
stripped off by an explicit AND operation.
This is probably best illustrated with a simple real program example.
Let's consider the following simple program:
$ cat foobar.c
int __attribute__ ((mips16)) foo (void)
{
return 1;
}
int __attribute__ ((mips16)) bar (void)
{
return 2;
}
int __attribute__ ((nomips16)) foo32 (void)
{
return 3;
}
int (*foo32p) (void) = foo32;
int (*foop) (void) = foo;
int fooi = (int) foo;
int
main (void)
{
return foop ();
}
$
This is plain C with no odd tricks, except from the instruction mode
attributes. They are not necessary to trigger this problem, I just put
them here so that the program can be contained in a single source file
and to make it obvious which function is MIPS16 code and which is not.
Let's try it with Linux, so that everyone can repeat this experiment:
$ mips-linux-gnu-gcc -mips16 -g -O2 -o foobar foobar.c
$
Let's have a look at some interesting symbols:
$ mips-linux-gnu-readelf -s foobar | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 7 entries:
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
66: 0040068c 4 FUNC GLOBAL DEFAULT [MIPS16] 12 bar
68: 00410848 4 OBJECT GLOBAL DEFAULT 21 foo32p
70: 00410844 4 OBJECT GLOBAL DEFAULT 21 foop
78: 00400684 8 FUNC GLOBAL DEFAULT 12 foo32
80: 00400680 4 FUNC GLOBAL DEFAULT [MIPS16] 12 foo
88: 00410840 4 OBJECT GLOBAL DEFAULT 21 fooi
$
Hmm, no sight of the ISA bit, but notice how foo and bar (but not
foo32!) have been marked as MIPS16 functions (ELF symbol structure's
`st_other' field is used for that).
So let's try to run and poke at this program with GDB. I'll be using a
native system for simplicity (I'll be using ellipses here and there to
remove unrelated clutter):
$ ./foobar
$ echo $?
1
$
So far, so good.
$ gdb ./foobar
[...]
(gdb) break main
Breakpoint 1 at 0x400490: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Yay, it worked! OK, so let's poke at it:
(gdb) print main
$1 = {int (void)} 0x400490 <main>
(gdb) print foo32
$2 = {int (void)} 0x400684 <foo32>
(gdb) print foo32p
$3 = (int (*)(void)) 0x400684 <foo32>
(gdb) print bar
$4 = {int (void)} 0x40068c <bar>
(gdb) print foo
$5 = {int (void)} 0x400680 <foo>
(gdb) print foop
$6 = (int (*)(void)) 0x400681 <foo>
(gdb)
A-ha! Here's the difference and finally the ISA bit!
(gdb) print /x fooi
$7 = 0x400681
(gdb) p/x $pc
p/x $pc
$8 = 0x400491
(gdb)
And here as well...
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
main () at foobar.c:24
24 }
Value returned is $9 = 1
(gdb) continue
Continuing.
[Inferior 1 (process 14103) exited with code 01]
(gdb)
So let's be a bit inquisitive...
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Actually we do not like to run foo here at all. Let's run bar instead!
(gdb) set foop = bar
(gdb) print foop
$10 = (int (*)(void)) 0x40068c <bar>
(gdb)
Hmm, no ISA bit. Is it going to work?
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) p/x $pc
$11 = 0x40068c
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068c <+0>: jr ra
0x0040068e <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
Program received signal SIGILL, Illegal instruction.
bar () at foobar.c:9
9 }
(gdb)
Oops!
(gdb) p/x $pc
$12 = 0x40068c
(gdb)
We're still there!
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
So let's try something else:
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
=> 0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
Program received signal SIGILL, Illegal instruction.
foo () at foobar.c:4
4 }
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
The same problem!
(gdb) run
Starting program:
/net/build2-lucid-cs/scratch/macro/mips-linux-fsf-gcc/isa-bit/foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo32
(gdb) advance foo32
foo32 () at foobar.c:14
14 }
(gdb) disassemble
Dump of assembler code for function foo32:
=> 0x00400684 <+0>: jr ra
0x00400688 <+4>: li v0,3
End of assembler dump.
(gdb) finish
Run till exit from #0 foo32 () at foobar.c:14
main () at foobar.c:24
24 }
Value returned is $14 = 3
(gdb) continue
Continuing.
[Inferior 1 (process 14113) exited with code 03]
(gdb)
That did work though, so it's the ISA bit only!
(gdb) quit
Enough!
That's the tip of the iceberg only though. So let's rebuild the
executable with some dynamic symbols:
$ mips-linux-gnu-gcc -mips16 -Wl,--export-dynamic -g -O2 -o foobar-dyn foobar.c
$ mips-linux-gnu-readelf -s foobar-dyn | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 32 entries:
6: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
8: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
9: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
15: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
17: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
25: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
69: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
71: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
72: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
79: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
81: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
89: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
$
OK, now the ISA bit is there for a change, but the MIPS16 `st_other'
attribute gone, hmm... What does `objdump' do then:
$ mips-linux-gnu-objdump -Tt foobar-dyn | egrep 'SYMBOL|foo|bar'
foobar-dyn: file format elf32-tradbigmips
SYMBOL TABLE:
00000000 l df *ABS* 00000000 foobar.c
004009cc g F .text 00000004 0xf0 bar
00410b88 g O .data 00000004 foo32p
00410b84 g O .data 00000004 foop
004009c4 g F .text 00000008 foo32
004009c0 g F .text 00000004 0xf0 foo
00410b80 g O .data 00000004 fooi
DYNAMIC SYMBOL TABLE:
004009cc g DF .text 00000004 Base 0xf0 bar
00410b88 g DO .data 00000004 Base foo32p
00410b84 g DO .data 00000004 Base foop
004009c4 g DF .text 00000008 Base foo32
004009c0 g DF .text 00000004 Base 0xf0 foo
00410b80 g DO .data 00000004 Base fooi
$
Hmm, the attribute (0xf0, printed raw) is back, and the ISA bit gone
again.
Let's have a look at some DWARF-2 records GDB uses (I'll be stripping
off a lot here for brevity) -- debug info:
$ mips-linux-gnu-readelf -wi foobar
Contents of the .debug_info section:
[...]
Compilation Unit @ offset 0x88:
Length: 0xbb (32-bit)
Version: 4
Abbrev Offset: 62
Pointer Size: 4
<0><93>: Abbrev Number: 1 (DW_TAG_compile_unit)
<94> DW_AT_producer : (indirect string, offset: 0x19e): GNU C 4.8.0 20120513 (experimental) -meb -mips16 -march=mips32r2 -mhard-float -mllsc -mplt -mno-synci -mno-shared -mabi=32 -g -O2
<98> DW_AT_language : 1 (ANSI C)
<99> DW_AT_name : (indirect string, offset: 0x190): foobar.c
<9d> DW_AT_comp_dir : (indirect string, offset: 0x225): [...]
<a1> DW_AT_ranges : 0x0
<a5> DW_AT_low_pc : 0x0
<a9> DW_AT_stmt_list : 0x27
<1><ad>: Abbrev Number: 2 (DW_TAG_subprogram)
<ae> DW_AT_external : 1
<ae> DW_AT_name : foo
<b2> DW_AT_decl_file : 1
<b3> DW_AT_decl_line : 1
<b4> DW_AT_prototyped : 1
<b4> DW_AT_type : <0xc2>
<b8> DW_AT_low_pc : 0x400680
<bc> DW_AT_high_pc : 0x400684
<c0> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<c2> DW_AT_GNU_all_call_sites: 1
<1><c2>: Abbrev Number: 3 (DW_TAG_base_type)
<c3> DW_AT_byte_size : 4
<c4> DW_AT_encoding : 5 (signed)
<c5> DW_AT_name : int
<1><c9>: Abbrev Number: 4 (DW_TAG_subprogram)
<ca> DW_AT_external : 1
<ca> DW_AT_name : (indirect string, offset: 0x18a): foo32
<ce> DW_AT_decl_file : 1
<cf> DW_AT_decl_line : 11
<d0> DW_AT_prototyped : 1
<d0> DW_AT_type : <0xc2>
<d4> DW_AT_low_pc : 0x400684
<d8> DW_AT_high_pc : 0x40068c
<dc> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<de> DW_AT_GNU_all_call_sites: 1
<1><de>: Abbrev Number: 2 (DW_TAG_subprogram)
<df> DW_AT_external : 1
<df> DW_AT_name : bar
<e3> DW_AT_decl_file : 1
<e4> DW_AT_decl_line : 6
<e5> DW_AT_prototyped : 1
<e5> DW_AT_type : <0xc2>
<e9> DW_AT_low_pc : 0x40068c
<ed> DW_AT_high_pc : 0x400690
<f1> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<f3> DW_AT_GNU_all_call_sites: 1
<1><f3>: Abbrev Number: 5 (DW_TAG_subprogram)
<f4> DW_AT_external : 1
<f4> DW_AT_name : (indirect string, offset: 0x199): main
<f8> DW_AT_decl_file : 1
<f9> DW_AT_decl_line : 21
<fa> DW_AT_prototyped : 1
<fa> DW_AT_type : <0xc2>
<fe> DW_AT_low_pc : 0x400490
<102> DW_AT_high_pc : 0x4004a4
<106> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<108> DW_AT_GNU_all_tail_call_sites: 1
[...]
$
-- no sign of the ISA bit anywhere -- frame info:
$ mips-linux-gnu-readelf -wf foobar
[...]
Contents of the .debug_frame section:
00000000 0000000c ffffffff CIE
Version: 1
Augmentation: ""
Code alignment factor: 1
Data alignment factor: -4
Return address column: 31
DW_CFA_def_cfa_register: r29
DW_CFA_nop
00000010 0000000c 00000000 FDE cie=00000000 pc=00400680..00400684
00000020 0000000c 00000000 FDE cie=00000000 pc=00400684..0040068c
00000030 0000000c 00000000 FDE cie=00000000 pc=0040068c..00400690
00000040 00000018 00000000 FDE cie=00000000 pc=00400490..004004a4
DW_CFA_advance_loc: 6 to 00400496
DW_CFA_def_cfa_offset: 32
DW_CFA_offset: r31 at cfa-4
DW_CFA_advance_loc: 6 to 0040049c
DW_CFA_restore: r31
DW_CFA_def_cfa_offset: 0
DW_CFA_nop
DW_CFA_nop
DW_CFA_nop
[...]
$
-- no sign of the ISA bit anywhere -- range info (GDB doesn't use arange):
$ mips-linux-gnu-readelf -wR foobar
Contents of the .debug_ranges section:
Offset Begin End
00000000 00400680 00400690
00000000 00400490 004004a4
00000000 <End of list>
$
-- no sign of the ISA bit anywhere -- line info:
$ mips-linux-gnu-readelf -wl foobar
Raw dump of debug contents of section .debug_line:
[...]
Offset: 0x27
Length: 78
DWARF Version: 2
Prologue Length: 31
Minimum Instruction Length: 1
Initial value of 'is_stmt': 1
Line Base: -5
Line Range: 14
Opcode Base: 13
Opcodes:
Opcode 1 has 0 args
Opcode 2 has 1 args
Opcode 3 has 1 args
Opcode 4 has 1 args
Opcode 5 has 1 args
Opcode 6 has 0 args
Opcode 7 has 0 args
Opcode 8 has 0 args
Opcode 9 has 1 args
Opcode 10 has 0 args
Opcode 11 has 0 args
Opcode 12 has 1 args
The Directory Table is empty.
The File Name Table:
Entry Dir Time Size Name
1 0 0 0 foobar.c
Line Number Statements:
Extended opcode 2: set Address to 0x400681
Special opcode 6: advance Address by 0 to 0x400681 and Line by 1 to 2
Special opcode 7: advance Address by 0 to 0x400681 and Line by 2 to 4
Special opcode 55: advance Address by 3 to 0x400684 and Line by 8 to 12
Special opcode 7: advance Address by 0 to 0x400684 and Line by 2 to 14
Advance Line by -7 to 7
Special opcode 131: advance Address by 9 to 0x40068d and Line by 0 to 7
Special opcode 7: advance Address by 0 to 0x40068d and Line by 2 to 9
Advance PC by 3 to 0x400690
Extended opcode 1: End of Sequence
Extended opcode 2: set Address to 0x400491
Advance Line by 21 to 22
Copy
Special opcode 6: advance Address by 0 to 0x400491 and Line by 1 to 23
Special opcode 60: advance Address by 4 to 0x400495 and Line by -1 to 22
Special opcode 34: advance Address by 2 to 0x400497 and Line by 1 to 23
Special opcode 62: advance Address by 4 to 0x40049b and Line by 1 to 24
Special opcode 32: advance Address by 2 to 0x40049d and Line by -1 to 23
Special opcode 6: advance Address by 0 to 0x40049d and Line by 1 to 24
Advance PC by 7 to 0x4004a4
Extended opcode 1: End of Sequence
[...]
-- a-ha, the ISA bit is there! However it's not always right for some
reason, I don't have a small test case to show it, but here's an excerpt
from MIPS16 libc, a prologue of a function:
00019630 <__libc_init_first>:
19630: e8a0 jrc ra
19632: 6500 nop
00019634 <_init>:
19634: f000 6a11 li v0,17
19638: f7d8 0b08 la v1,15e00 <_DYNAMIC+0x15c54>
1963c: f400 3240 sll v0,16
19640: e269 addu v0,v1
19642: 659a move gp,v0
19644: 64f6 save 48,ra,s0-s1
19646: 671c move s0,gp
19648: d204 sw v0,16(sp)
1964a: f352 984c lw v0,-27828(s0)
1964e: 6724 move s1,a0
and the corresponding DWARF-2 line info:
Line Number Statements:
Extended opcode 2: set Address to 0x19631
Advance Line by 44 to 45
Copy
Special opcode 8: advance Address by 0 to 0x19631 and Line by 3 to 48
Special opcode 66: advance Address by 4 to 0x19635 and Line by 5 to 53
Advance PC by constant 17 to 0x19646
Special opcode 25: advance Address by 1 to 0x19647 and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 33: advance Address by 2 to 0x19649 and Line by 0 to 53
Special opcode 39: advance Address by 2 to 0x1964b and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 61: advance Address by 4 to 0x1964f and Line by 0 to 53
-- see that "Advance PC by constant 17" there? It clears the ISA bit,
however code at 0x19646 is not standard MIPS code at all. For some
reason the constant is always 17, I've never seen DW_LNS_const_add_pc
used with any other value -- is that a binutils bug or what?
3. Solution:
I think we should retain the value of the ISA bit in code references,
that is effectively treat them as cookies as they indeed are (although
trivially calculated) rather than raw memory byte addresses.
In a perfect world both the static symbol table and the respective
DWARF-2 records should be fixed to include the ISA bit in all the cases.
I think however that this is infeasible.
All the uses of `_bfd_mips_elf_symbol_processing' can not necessarily be
tracked down. This function is used by `elf_slurp_symbol_table' that in
turn is used by `bfd_canonicalize_symtab' and
`bfd_canonicalize_dynamic_symtab', which are public interfaces.
Similarly DWARF-2 records are used outside GDB, one notable if a bit
questionable is the exception unwinder (libgcc/unwind-dw2.c) -- I have
identified at least bits in `execute_cfa_program' and
`uw_frame_state_for', both around the calls to `_Unwind_IsSignalFrame',
that would need an update as they effectively flip the ISA bit freely;
see also the comment about MASK_RETURN_ADDR in gcc/config/mips/mips.h.
But there may be more places. Any change in how DWARF-2 records are
produced would require an update there and would cause compatibility
problems with libgcc.a binaries already distributed; given that this is
a static library a complex change involving function renames would
likely be required.
I propose therefore to accept the existing inconsistencies and deal with
them entirely within GDB. I have figured out that the ISA bit lost in
various places can still be recovered as long as we have symbol
information -- that'll have the `st_other' attribute correctly set to
one of standard MIPS/MIPS16/microMIPS encoding.
Here's the resulting change. It adds a couple of new `gdbarch' hooks,
one to update symbol information with the ISA bit lost in
`_bfd_mips_elf_symbol_processing', and two other ones to adjust DWARF-2
records as they're processed. The ISA bit is set in each address
handled according to information retrieved from the symbol table for the
symbol spanning the address if any; limits are adjusted based on the
address they point to related to the respective base address.
Additionally minimal symbol information has to be adjusted accordingly
in its gdbarch hook.
With these changes in place some complications with ISA bit juggling in
the PC that never fully worked can be removed from the MIPS backend.
Conversely, the generic dynamic linker event special breakpoint symbol
handler has to be updated to call the minimal symbol gdbarch hook to
record that the symbol is a MIPS16 or microMIPS address if applicable or
the breakpoint will be set at the wrong address and either fail to work
or cause SIGTRAPs (this is because the symbol is handled early on and
bypasses regular symbol processing).
4. Results obtained
The change fixes the example above -- to repeat only the crucial steps:
(gdb) break main
Breakpoint 1 at 0x400491: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) print foo
$1 = {int (void)} 0x400681 <foo>
(gdb) set foop = bar
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068d <+0>: jr ra
0x0040068f <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
main () at foobar.c:24
24 }
Value returned is $2 = 2
(gdb) continue
Continuing.
[Inferior 1 (process 14128) exited with code 02]
(gdb)
-- excellent!
The change removes about 90 failures per MIPS16 multilib in mips-sde-elf
testing too, results for MIPS16 are now similar to that for standard
MIPS; microMIPS results are a bit worse because of host-I/O problems in
QEMU used instead of MIPSsim for microMIPS testing only:
=== gdb Summary ===
# of expected passes 14299
# of unexpected failures 187
# of expected failures 56
# of known failures 58
# of unresolved testcases 11
# of untested testcases 52
# of unsupported tests 174
MIPS16:
=== gdb Summary ===
# of expected passes 14298
# of unexpected failures 187
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 12
# of untested testcases 52
# of unsupported tests 174
microMIPS:
=== gdb Summary ===
# of expected passes 14149
# of unexpected failures 201
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 7
# of untested testcases 53
# of unsupported tests 175
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
Maciej W. Rozycki <macro@mips.com>
Pedro Alves <pedro@codesourcery.com>
gdb/
* gdbarch.sh (elf_make_msymbol_special): Change type to `F',
remove `predefault' and `invalid_p' initializers.
(make_symbol_special): New architecture method.
(adjust_dwarf2_addr, adjust_dwarf2_line): Likewise.
(objfile, symbol): New declarations.
* arch-utils.h (default_elf_make_msymbol_special): Remove
prototype.
(default_make_symbol_special): New prototype.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* mips-tdep.h (mips_unmake_compact_addr): New prototype.
* arch-utils.c (default_elf_make_msymbol_special): Remove
function.
(default_make_symbol_special): New function.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* dwarf2-frame.c (decode_frame_entry_1): Call
`gdbarch_adjust_dwarf2_addr'.
* dwarf2loc.c (dwarf2_find_location_expression): Likewise.
* dwarf2read.c (create_addrmap_from_index): Likewise.
(process_psymtab_comp_unit_reader): Likewise.
(add_partial_symbol): Likewise.
(add_partial_subprogram): Likewise.
(process_full_comp_unit): Likewise.
(read_file_scope): Likewise.
(read_func_scope): Likewise. Call `gdbarch_make_symbol_special'.
(read_lexical_block_scope): Call `gdbarch_adjust_dwarf2_addr'.
(read_call_site_scope): Likewise.
(dwarf2_ranges_read): Likewise.
(dwarf2_record_block_ranges): Likewise.
(read_attribute_value): Likewise.
(dwarf_decode_lines_1): Call `gdbarch_adjust_dwarf2_line'.
(new_symbol_full): Call `gdbarch_adjust_dwarf2_addr'.
* elfread.c (elf_symtab_read): Don't call
`gdbarch_elf_make_msymbol_special' if unset.
* mips-linux-tdep.c (micromips_linux_sigframe_validate): Strip
the ISA bit from the PC.
* mips-tdep.c (mips_unmake_compact_addr): New function.
(mips_elf_make_msymbol_special): Set the ISA bit in the symbol's
address appropriately.
(mips_make_symbol_special): New function.
(mips_pc_is_mips): Set the ISA bit before symbol lookup.
(mips_pc_is_mips16): Likewise.
(mips_pc_is_micromips): Likewise.
(mips_pc_isa): Likewise.
(mips_adjust_dwarf2_addr): New function.
(mips_adjust_dwarf2_line): Likewise.
(mips_read_pc, mips_unwind_pc): Keep the ISA bit.
(mips_addr_bits_remove): Likewise.
(mips_skip_trampoline_code): Likewise.
(mips_write_pc): Don't set the ISA bit.
(mips_eabi_push_dummy_call): Likewise.
(mips_o64_push_dummy_call): Likewise.
(mips_gdbarch_init): Install `mips_make_symbol_special',
`mips_adjust_dwarf2_addr' and `mips_adjust_dwarf2_line' gdbarch
handlers.
* solib.c (gdb_bfd_lookup_symbol_from_symtab): Get
target-specific symbol address adjustments.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
gdb/testsuite/
* gdb.base/func-ptrs.c: New file.
* gdb.base/func-ptrs.exp: New file.
This patch intends to partially fix PR breakpoints/10737, which is
about making the syscall information (for the "catch syscall" command)
be per-arch, instead of global. This is not a full fix because of the
other issues pointed by Pedro here:
<https://sourceware.org/bugzilla/show_bug.cgi?id=10737#c5>
However, I consider it a good step towards the real fix. It will also
help me fix <https://sourceware.org/bugzilla/show_bug.cgi?id=17402>.
What this patch does, basically, is move the "syscalls_info"
struct to gdbarch. Currently, the syscall information is stored in a
global variable inside gdb/xml-syscall.c, which means that there is no
easy way to correlate this info with the current target or
architecture being used, for example. This causes strange behaviors,
because the syscall info is not re-read when the arch changes. For
example, if you put a syscall catchpoint in syscall 5 on i386 (syscall
open), and then load a x86_64 program on GDB and put the same syscall
5 there (fstat on x86_64), you will still see that GDB tells you that
it is catching "open", even though it is not. With this patch, GDB
correctly says that it will be catching fstat syscalls.
(gdb) set architecture i386
The target architecture is assumed to be i386
(gdb) catch syscall 5
Catchpoint 1 (syscall 'open' [5])
(gdb) set architecture i386:x86-64
The target architecture is assumed to be i386:x86-64
(gdb) catch syscall 5
Catchpoint 2 (syscall 'open' [5])
But with the patch:
(gdb) set architecture i386
The target architecture is assumed to be i386
(gdb) catch syscall 5
Catchpoint 1 (syscall 'open' [5])
(gdb) set architecture i386:x86-64
The target architecture is assumed to be i386:x86-64
(gdb) catch syscall 5
Catchpoint 2 (syscall 'fstat' [5])
As I said, there are still some problems on the "catch syscall"
mechanism, because (for example) the user should be able to "catch
syscall open" on i386, and then expect "open" to be caught also on
x86_64. Currently, it doesn't work. I intend to work on this later.
gdb/
2014-11-20 Sergio Durigan Junior <sergiodj@redhat.com>
PR breakpoints/10737
* amd64-linux-tdep.c (amd64_linux_init_abi_common): Adjust call to
set_xml_syscall_file_name to provide gdbarch.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* bfin-linux-tdep.c (bfin_linux_init_abi): Likewise.
* breakpoint.c (print_it_catch_syscall): Adjust call to
get_syscall_by_number to provide gdbarch.
(print_one_catch_syscall): Likewise.
(print_mention_catch_syscall): Likewise.
(print_recreate_catch_syscall): Likewise.
(catch_syscall_split_args): Adjust calls to get_syscall_by_number
and get_syscall_by_name to provide gdbarch.
(catch_syscall_completer): Adjust call to get_syscall_names to
provide gdbarch.
* gdbarch.c: Regenerate.
* gdbarch.h: Likewise.
* gdbarch.sh: Forward declare "struct syscalls_info".
(xml_syscall_file): New variable.
(syscalls_info): Likewise.
* i386-linux-tdep.c (i386_linux_init_abi): Adjust call to
set_xml_syscall_file_name to provide gdbarch.
* mips-linux-tdep.c (mips_linux_init_abi): Likewise.
* ppc-linux-tdep.c (ppc_linux_init_abi): Likewise.
* s390-linux-tdep.c (s390_gdbarch_init): Likewise.
* sparc-linux-tdep.c (sparc32_linux_init_abi): Likewise.
* sparc64-linux-tdep.c (sparc64_linux_init_abi): Likewise.
* xml-syscall.c: Include gdbarch.h.
(set_xml_syscall_file_name): Accept gdbarch parameter.
(get_syscall_by_number): Likewise.
(get_syscall_by_name): Likewise.
(get_syscall_names): Likewise.
(my_gdb_datadir): Delete global variable.
(struct syscalls_info) <my_gdb_datadir>: New variable.
(struct syscalls_info) <sysinfo>: Rename variable to
"syscalls_info".
(sysinfo): Delete global variable.
(have_initialized_sysinfo): Likewise.
(xml_syscall_file): Likewise.
(sysinfo_free_syscalls_desc): Rename to...
(syscalls_info_free_syscalls_desc): ... this.
(free_syscalls_info): Rename "sysinfo" to "syscalls_info". Adjust
code to the new layout of "struct syscalls_info".
(make_cleanup_free_syscalls_info): Rename parameter "sysinfo" to
"syscalls_info".
(syscall_create_syscall_desc): Likewise.
(syscall_start_syscall): Likewise.
(syscall_parse_xml): Likewise.
(xml_init_syscalls_info): Likewise. Drop "const" from return value.
(init_sysinfo): Rename to...
(init_syscalls_info): ...this. Add gdbarch as a parameter.
Adjust function to deal with gdbarch.
(xml_get_syscall_number): Delete parameter sysinfo. Accept
gdbarch as a parameter. Adjust code.
(xml_get_syscall_name): Likewise.
(xml_list_of_syscalls): Likewise.
(set_xml_syscall_file_name): Accept gdbarch as parameter.
(get_syscall_by_number): Likewise.
(get_syscall_by_name): Likewise.
(get_syscall_names): Likewise.
* xml-syscall.h (set_xml_syscall_file_name): Likewise.
(get_syscall_by_number): Likewise.
(get_syscall_by_name): Likewise.
(get_syscall_names): Likewise.
gdb/testsuite/
2014-11-20 Sergio Durigan Junior <sergiodj@redhat.com>
PR breakpoints/10737
* gdb.base/catch-syscall.exp (do_syscall_tests): Call
test_catch_syscall_multi_arch.
(test_catch_syscall_multi_arch): New function.
Yao Qi
Simon Marchi
Maciej W. Rozycki
John Baldwin
Simon Marchi
Jiong Wang
Pedro Alves
Peter Bergner
Joel Brobecker
Ulrich Weigand
Yao Qi
Walfred Tedeschi
Marcin Kościelnicki
Doug Evans
Aleksandar Ristovski
Patrick Palka
Pierre Langlois
Jan Kratochvil
Martin Galvan
Jose E. Marchesi
Andreas Arnez
Yao Qi
Tom Tromey
Maciej W. Rozycki
Sergio Durigan Junior