gdb_pretty_print_insn allocates and destroys a couple local buffers
each time it is called, which can be many times when disassembling a
region of memory. Avoid that overhead by adding a new class that
holds the buffers and making gdb_pretty_print_insn a method of that
class, so that the buffers can be reused across calls.
gdb/ChangeLog:
2017-02-02 Pedro Alves <palves@redhat.com>
* disasm.c (gdb_pretty_print_insn): Rename to ...
(gdb_pretty_print_disassembler::pretty_print_insn): ... this.
Remove gdbarch parameter. Adapt to clear the object's buffers
instead of allocating new buffers, and to print using the object's
gdb_disassembler instead of calling gdb_print_insn.
(dump_insns): Use gdb_pretty_print_disassembler.
* disasm.h (gdb_pretty_print_insn): Delete declaration.
(gdb_pretty_print_disassembler): New class.
* record-btrace.c (btrace_insn_history): Use
gdb_pretty_print_disassembler.
ui_file_rewind is a ui_file method that only really works with mem
buffer files, and is a nop on other ui_file types. It'd be desirable
to eliminate it from the base ui_file interface, and move it to the
"mem_fileopen" subclass of ui_file instead. A following patch does
just that.
Unfortunately, there are a couple references to ui_file_rewind inside
gdb_disassembler::pretty_print_insn that were made harder to eliminate
with the recent addition of the gdb_disassembler wrapper.
Before the gdb_disassembler wrapper was added, in commit
e47ad6c0bd ("Refactor disassembly code"), gdb_pretty_print_insn
used to be passed a ui_file pointer as argument, and it was simple to
adjust that pointer be a "mem_fileopen" ui_file pointer instead, since
there's only one gdb_pretty_print_insn caller.
That commit made gdb_pretty_print_insn be a method of
gdb_disassembler, and removed the method's ui_file parameter at the
same time, replaced by referencing the gdb_disassembler's stream
instead. The trouble is that a gdb_disassembler can be instantiated
with a pointer any kind of ui_file. Casting the gdb_disassembler's
stream to a mem_fileopen ui_file inside
gdb_disassembler::pretty_print_insn in order to call the reset method
would be gross hack.
The fix here is to:
- make gdb_disassembler::pretty_print_insn a be free function again
instead of a method of gdb_disassembler. I.e., bring back
gdb_pretty_print_insn.
- but, don't add back the ui_file * parameter. Instead, move the
mem_fileopen allocation inside. That is a better interface, given
that the ui_file is only ever used as temporary scratch buffer as
an implementation detail of gdb_pretty_print_insn. The function's
real "where to send output" parameter is the ui_out pointer. (A
following patch will add back buffer reuse across invocations
differently).
- don't add back a disassemble_info pointer either. That used to be
necessary for this bit:
err = m_di.read_memory_func (pc, &data, 1, &m_di);
if (err != 0)
m_di.memory_error_func (err, pc, &m_di);
... but AFAIK, it's not really necessary. We can replace those
three lines with a call to read_code. This seems to fix a
regression even, because before commit d8b49cf0c8 ("Don't throw
exception in dis_asm_memory_error"), that memory_error_func call
would throw an error/exception, but now it only records the error
in the gdb_disassembler's m_err_memaddr field. (read_code throws
on error.)
With all these, gdb_pretty_print_insn is completely layered on top of
gdb_disassembler only using the latter's public API.
gdb/ChangeLog:
2017-02-02 Pedro Alves <palves@redhat.com>
* disasm.c (gdb_disassembler::pretty_print_insn): Rename to...
(gdb_pretty_print_insn): ... this. Now a free function. Add back
a 'gdbarch' parameter. Allocate a mem_fileopen stream here.
Adjust to call gdb_print_insn instead of
gdb_disassembler::print_insn.
(dump_insns, do_mixed_source_and_assembly_deprecated)
(do_mixed_source_and_assembly, do_assembly_only): Add back a
'gdbarch' parameter. Remove gdb_disassembler parameter.
(gdb_disassembly): Don't allocate a gdb_disassembler here.
* disasm.h (gdb_disassembler::pretty_print_insn): Delete
declaration.
(gdb_pretty_print_insn): Re-add declaration.
* record-btrace.c (btrace_insn_history): Don't allocate a
gdb_disassembler here. Adjust to call gdb_pretty_print_insn.
The file_string parameter was added in 8f0eea0 (sorry, no title back
then) and has never actually been used.
gdb/ChangeLog:
* disasm.h (gdb_disassembly): Remove file_string parameter.
* disasm.c (gdb_disassembly): Likewise.
* cli/cli-cmds.c (print_disassembly): Adapt.
* mi/mi-cmd-disas.c (mi_cmd_disassemble): Likewise.
* stack.c (do_gdb_disassembly): Likewise.
Hi,
GDB calls some APIs from opcodes to do disassembly and provide some
call backs. This model makes troubles on C++ exception unwinding,
because GDB is a C++ program, and opcodes is still compiled as C.
As we can see, frame #10 and #12 are C++, while #frame 11 is C,
#10 0x0000000000544228 in memory_error (err=TARGET_XFER_E_IO, memaddr=<optimized out>) at ../../binutils-gdb/gdb/corefile.c:237
#11 0x00000000006b0a54 in print_insn_aarch64 (pc=0, info=0xffffffffeeb0) at ../../binutils-gdb/opcodes/aarch64-dis.c:3185
#12 0x0000000000553590 in gdb_pretty_print_insn (gdbarch=gdbarch@entry=0xbbceb0, uiout=uiout@entry=0xbc73d0, di=di@entry=0xffffffffeeb0,
insn=0xffffffffed40, insn@entry=0xffffffffed90, flags=flags@entry=0,
C++ exception unwinder can't go across frame #11 unless it has
unwind table. However, C program on many architectures doesn't
have it in default. As a result, GDB aborts, which is described
in PR 20939.
This is not the first time we see this kind of problem. We've
had a commit 89525768cd
"Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH".
We can fix the disassembly bug in a similar way, this is the option one.
Since opcodes is built with gdb, we fix this problem in a different
way as we did for the same issue with readline. Instead of throwing
exception in dis_asm_memory_error, we record the failed memory
address, and throw exception when GDB returns from opcodes disassemblers.
gdb:
2017-01-26 Yao Qi <yao.qi@linaro.org>
Pedro Alves <palves@redhat.com>
PR gdb/20939
* disasm.c (gdb_disassembler::dis_asm_memory_error): Don't
call memory_error, save memaddr instead.
(gdb_disassembler::print_insn): If gdbarch_print_insn returns
negative, cal memory_error.
* disasm.h (gdb_disassembler) <m_err_memaddr>: New field.
gdb/testsuite:
2017-01-26 Yao Qi <yao.qi@linaro.org>
* gdb.base/all-architectures.exp.in (do_arch_tests): Test
disassemble on address 0.
This patch addes class gdb_disassembler, and refactor
code to use it. The gdb_disassembler object is saved
in disassember_info.application_data. However,
disassember_info.application_data is already used by
gdb for arm, mips spu, and scm-disasm. In arm and mips,
.application_data is gdbarch, but we can still get gdbarch
from gdb_disassember.
The use of application_data in spu is a little bit
complicated. It creates its own disassemble_info, and
save spu_dis_asm_data in .application_data. This will
overwrite the pointer to gdb_disassembler, so we need
to find another place to save spu_dis_asm_data. I
extend disassemble_info, and put "id" there.
gdb:
2017-01-26 Pedro Alves <palves@redhat.com>
Yao Qi <yao.qi@linaro.org>
* arm-tdep.c: Include "disasm.h".
(gdb_print_insn_arm): Update code to get gdbarch.
* disasm.c (dis_asm_read_memory): Change it to
gdb_disassembler::dis_asm_read_memory.
(dis_asm_memory_error): Likewise.
(dis_asm_print_address): Likewise.
(gdb_pretty_print_insn): Change it to
gdb_disassembler::pretty_print_insn.
(dump_insns): Add one argument gdb_disassemlber. All
callers updated.
(do_mixed_source_and_assembly_deprecated): Likewise.
(do_mixed_source_and_assembly): Likewise.
(do_assembly_only): Likewise.
(gdb_disassembler::gdb_disassembler): New.
(gdb_disassembler::print_insn): New.
* disasm.h (class gdb_disassembler): New.
(gdb_pretty_print_insn): Remove declaration.
(gdb_disassemble_info): Likewise.
* guile/scm-disasm.c (class gdbscm_disassembler): New.
(gdbscm_disasm_read_memory_worker): Update.
(gdbscm_disasm_read_memory): Update.
(gdbscm_disasm_memory_error): Remove.
(gdbscm_disasm_print_address): Remove.
(gdbscm_disassembler::gdbscm_disassembler): New.
(gdbscm_print_insn_from_port): Update.
* mips-tdep.c: Include disasm.h.
(gdb_print_insn_mips): Update code to get gdbarch.
* record-btrace.c (btrace_insn_history): Update.
* spu-tdep.c: Include disasm.h.
(struct spu_dis_asm_data): Remove.
(struct spu_dis_asm_info): New.
(spu_dis_asm_print_address): Use spu_dis_asm_info to get
SPU id.
(gdb_print_insn_spu): Cast disassemble_info to
spu_dis_asm_info.
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.
The "record instruction-history" command prints for each instruction in
addition to the instruction's disassembly:
- the instruction number in the recorded execution trace
- a '?' before the instruction if it was executed speculatively
To allow the "record instruction-history" command to use GDB's disassembly
infrastructure, we extend gdb_pretty_print_insn to optionally print those
additional fields and export the function.
Add a new struct disasm_insn to add additional fields describing the
to-be-disassembled instruction. The additional fields are:
number an optional instruction number, zero if omitted.
is_speculative a predicate saying whether the instruction was
executed speculatively.
If non-zero, the instruction number is printed first. It will also appear
as a new optional field "insn-number" in MI. The field will be present if
insn_num is non-zero.
If is_speculative is set, speculative execution will be indicated by a "?"
following the new instruction number field. Unless the PC is omitted, it
will overwrite the first byte of the PC prefix. It will appear as a new
optional field "is-speculative" in MI. The field will contain "?" and will
be present if is_speculative is set.
The speculative execution indication is guarded by a new flag
DISASSEMBLY_SPECULATION.
Replace the PC parameter of gdb_pretty_print_insn with a pointer to the above
struct. GDB's "disassemble" command does not use the new fields.
gdb/
* disasm.h (DISASSEMBLY_SPECULATION): New.
(struct disasm_insn): New.
(gdb_pretty_print_insn): New.
* disasm.c (gdb_pretty_print_insn): Replace parameter PC with INSN.
Update users. Print instruction number and indicate speculative
execution, if requested.
The "source centric" /m option to the disassemble command is often
unhelpful, e.g., in the presence of optimized code.
This patch adds a /s modifier that is better.
For one, /m only prints instructions from the originating source file,
leaving out instructions from e.g., inlined functions from other files.
gdb/ChangeLog:
PR gdb/11833
* NEWS: Document new /s modifier for the disassemble command.
* cli/cli-cmds.c (disassemble_command): Add support for /s.
(_initialize_cli_cmds): Update online docs of disassemble command.
* disasm.c: #include "source.h".
(struct deprecated_dis_line_entry): Renamed from dis_line_entry.
All uses updated.
(dis_line_entry): New struct.
(hash_dis_line_entry, eq_dis_line_entry): New functions.
(allocate_dis_line_table): New functions.
(maybe_add_dis_line_entry, line_has_code_p): New functions.
(dump_insns): New arg end_pc. All callers updated.
(do_mixed_source_and_assembly_deprecated): Renamed from
do_mixed_source_and_assembly. All callers updated.
(do_mixed_source_and_assembly): New function.
(gdb_disassembly): Handle /s (DISASSEMBLY_SOURCE).
* disasm.h (DISASSEMBLY_SOURCE_DEPRECATED): Renamed from
DISASSEMBLY_SOURCE. All uses updated.
(DISASSEMBLY_SOURCE): New macro.
* mi/mi-cmd-disas.c (mi_cmd_disassemble): New modes 4,5.
gdb/doc/ChangeLog:
* gdb.texinfo (Machine Code): Update docs for mixed source/assembly
disassembly.
(GDB/MI Data Manipulation): Update docs for new disassembly modes.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-disassemble.exp: Update.
* gdb.base/disasm-optim.S: New file.
* gdb.base/disasm-optim.c: New file.
* gdb.base/disasm-optim.h: New file.
* gdb.base/disasm-optim.exp: New file.
instruction-history" command of record-btrace.
The pc prefix would appear multiple times in the branch trace disassembly,
which is more confusing than helpful.
gdb/
* record-btrace.c (btrace_insn_history): Omit the pc prefix in
the instruction history disassembly.
* disasm.c (dump_insns): Omit the pc prefix, if requested.
* disasm.h (DISASSEMBLY_OMIT_PC): New.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* disasm.c (do_mixed_source_and_assembly): Pass filename flag on
to print_source_lines ().
* symtab.h (PRINT_SOURCE_LINES_FILENAME): New print source lines
flag.
* source.c (print_source_lines_base): Prefix source line with
filename if PRINT_SOURCE_LINES_FILENAME flag is set.
* cli/cli-cmds.c (disassemble_command): Add a new modifier /r
to "disassemble" command to print the raw instructions in hex as
well as in symbolic form.
(init_cli_cmds): Ditto.
(print_disassembly): Change "mixed" to "flags" to translate
the behavior of disassemble.
(disassemble_current_function): Ditto.
* mi/mi-cmd-disas.c (mi_cmd_disassemble): Ditto.
* stack.c (gdb_disassembly_stub): Ditto.
* disasm.c (do_mixed_source_and_assembly): Ditto.
(do_mixed_source_and_assembly): Ditto.
(do_assembly_only): Ditto.
(gdb_disassembly): Ditto.
(dump_insns): print the raw instructions in hex as well as in
symbolic form if DISASSEMBLY_RAW_INSN and flags is true.
* disasm.h (DISASSEMBLY_SOURCE): Include source code with the
assembly if it and flags is true.
(DISASSEMBLY_RAW_INSN): Include the raw instructions in hex with
the assembly if it and flags is true.
(gdb_disassembly): Update extern.
* NEWS: Document disassemble/r support.
* disasm.c (gdb_print_insn): Return the number of branch delay
slot instructions too.
* disasm.h (gdb_print_insn): Update prototype.
* printcmd.c (branch_delay_insns): New variable to record the
number of delay slot instructions after disassembling a branch.
(print_formatted): Record the number of branch delay slot
instructions.
(do_examine): When disassembling, if the last instruction
disassembled has any branch delay slots, then bump the count so
that they get disassembled too.
* tui/tui-disasm.c (tui_disassemble): Update the call to
gdb_print_insn().
* NEWS: Document the new behaviour.
gdb/doc/:
* gdb.texinfo (Examining Memory): Document the new behaviour.
gdb/gdbtk/:
* generic/gdbtk-cmds.c (gdbtk_load_asm): Update the call to
gdb_print_insn().
* disasm.h: New file.
* mi/mi-cmd-disas.c (gdb_dis_asm_read_memory): Moved to disasm.c.
(compare_lines): Ditto.
(dump_insns): Ditto.
(do_mixed_source_and_assembly): Moved to disasm.c. Added uiout argument. (do_assembly_only): Ditto.
(do_disassembly): Renamed to gdb_disassembly and moved to disasm.c.
Sdded uiout argument.
* Makefile.in: Add new files. Reorder SFILES list. Update dependencies. Include libgdb.a later in the insight executable.