This mildly C++-ifies parser_state and stap_parse_info -- just enough
to remove some cleanups.
This version includes the changes implemented by Simon.
Regression tested by the buildbot.
gdb/ChangeLog
2017-12-30 Tom Tromey <tom@tromey.com>
Simon Marchi <simon.marchi@ericsson.com>
* stap-probe.h (struct stap_parse_info): Add constructor,
destructor.
* stap-probe.c (stap_parse_argument): Update.
* rust-exp.y (rust_lex_tests): Update.
* parser-defs.h (struct parser_state): Add constructor,
destructor, release method.
<expout>: Change type to expression_up.
(null_post_parser): Change type.
(initialize_expout, reallocate_expout): Remove.
* parse.c (parser_state::parser_state): Rename from
initialize_expout.
(parser_state::release): Rename from reallocate_expout.
(write_exp_elt, parse_exp_in_context_1, increase_expout_size):
Update.
(null_post_parser): Change type of "exp".
* dtrace-probe.c (dtrace_probe::build_arg_exprs): Update.
* ada-lang.c (resolve, resolve_subexp)
(replace_operator_with_call): Change type of "expp".
* language.h (struct language_defn) <la_post_parser>: Change type
of "expp".
Pedro has kindly pointed out that
gdb.arch/amd64-stap-optional-prefix.exp was failing after my
C++-ification patches touching the probe interface. The failure is
kind of cryptic:
77 break -pstap bar
78 Breakpoint 3 at 0x40048d
79 (gdb) PASS: gdb.arch/amd64-stap-optional-prefix.exp: bar: break -pstap bar
80 continue
81 Continuing.
82
83 Program received signal SIGILL, Illegal instruction.
84 main () at amd64-stap-optional-prefix.S:26
85 26 STAP_PROBE1(probe, foo, (%rsp))
It took me a while to figure out where this SIGILL is coming from.
Initially I thought it was something related to writing registers to
the inferior when dealing with probe arguments, but I discarded this
since the arguments were not touching any registers.
In the end, this was a mistake that was introduced during the review
process of the patch. When setting/clearing a SystemTap probe's
semaphore, the code was using 'm_address' (which refers the probe's
address) instead of 'm_sem_addr' (which refers to the semaphore's
address). This caused GDB to write a bogus value in the wrong memory
position, which in turn caused the SIGILL.
I am pushing this patch to correct the mistake.
On a side note: I told Pedro that the BuildBot hadn't caught the
failure during my try build, and for a moment there was a suspicion
that the BuildBot might be at fault here. However, I investigate this
and noticed that I only did one try build, with a patch that was
correctly using 'm_sem_addr' where applicable, and therefore no
failure should have happened indeed. I probably should have requested
another try build after addressing the review's comments, but they
were mostly basic and I didn't think it was needed. Oh, well.
2017-11-25 Sergio Durigan Junior <sergiodj@redhat.com>
PR gdb/22491
* stap-probe.c (relocate_address): New function.
(stap_probe::get_relocated_address): Use 'relocate_address'.
(stap_probe::set_semaphore): Use 'relocate_address' and pass
'm_sem_addr'.
(stap_probe::clear_semaphore): Likewise.
This patch converts the SystemTap probe
interface (gdb/stap-probe.[ch]) to C++, and also performs some
cleanups that were on my TODO list for a while.
The main changes were the conversion of 'struct stap_probe' to 'class
stap_probe', and a new 'class stap_static_probe_ops' to replace the
use of 'stap_probe_ops'. Both classes implement the virtual methods
exported by their parents, 'class probe' and 'class static_probe_ops',
respectively. I believe it's now a bit simpler to understand the
logic behind the stap-probe interface.
There are several helper functions used to parse parts of a stap
probe, and since they are generic and don't need to know about the
probe they're working on, I decided to leave them as simple static
functions (instead of e.g. converting them to class methods).
I've also converted a few uses of "VEC" to "std::vector", which makes
the code simpler and easier to maintain. And, as usual, some cleanups
here and there.
Even though I'm sending a series of patches, they need to be tested
and committed as a single unit, because of inter-dependencies. But it
should be easier to review in separate logical units.
I've regtested this patch on BuildBot, no regressions found.
gdb/ChangeLog:
2017-11-22 Sergio Durigan Junior <sergiodj@redhat.com>
Simon Marchi <simark@simark.ca>
* stap-probe.c (struct probe_ops stap_probe_ops): Delete
variable.
(struct stap_probe_arg) <stap_probe_arg>: New constructor.
<aexpr>: Change type to 'expression_up'.
(stap_probe_arg_s): Delete type and VEC.
(struct stap_probe): Delete. Replace by...
(class stap_static_probe_ops): ...this and...
(class stap_probe): ...this. Rename variables to add 'm_'
prefix. Do not use 'union' for arguments anymore.
(stap_get_expected_argument_type): Receive probe name instead
of 'struct stap_probe'. Adjust code.
(stap_parse_probe_arguments): Rename to...
(stap_probe::parse_arguments): ...this. Adjust code to
reflect change.
(stap_get_probe_address): Rename to...
(stap_probe::get_relocated_address): ...this. Adjust code
to reflect change.
(stap_get_probe_argument_count): Rename to...
(stap_probe::get_argument_count): ...this. Adjust code
to reflect change.
(stap_get_arg): Rename to...
(stap_probe::get_arg_by_number'): ...this. Adjust code to
reflect change.
(can_evaluate_probe_arguments): Rename to...
(stap_probe::can_evaluate_arguments): ...this. Adjust code
to reflect change.
(stap_evaluate_probe_argument): Rename to...
(stap_probe::evaluate_argument): ...this. Adjust code
to reflect change.
(stap_compile_to_ax): Rename to...
(stap_probe::compile_to_ax): ...this. Adjust code to
reflect change.
(stap_probe_destroy): Delete.
(stap_modify_semaphore): Adjust comment.
(stap_set_semaphore): Rename to...
(stap_probe::set_semaphore): ...this. Adjust code to reflect
change.
(stap_clear_semaphore): Rename to...
(stap_probe::clear_semaphore): ...this. Adjust code to
reflect change.
(stap_probe::get_static_ops): New method.
(handle_stap_probe): Adjust code to create instance of
'stap_probe'.
(stap_get_probes): Rename to...
(stap_static_probe_ops::get_probes): ...this. Adjust code to
reflect change.
(stap_probe_is_linespec): Rename to...
(stap_static_probe_ops::is_linespec): ...this. Adjust code to
reflect change.
(stap_type_name): Rename to...
(stap_static_probe_ops::type_name): ...this. Adjust code to
reflect change.
(stap_gen_info_probes_table_header): Rename to...
(stap_static_probe_ops::gen_info_probes_table_header):
...this. Adjust code to reflect change.
(stap_gen_info_probes_table_values): Rename to...
(stap_probe::gen_info_probes_table_values): ...this. Adjust
code to reflect change.
(struct probe_ops stap_probe_ops): Delete.
(info_probes_stap_command): Use 'info_probes_for_spops'
instead of 'info_probes_for_ops'.
(_initialize_stap_probe): Use 'all_static_probe_ops' instead
of 'all_probe_ops'.
This patch replaces the usage of VEC to store pointers to probe_ops with
an std::vector. The sole usage of that vector type is one global
variable that holds the ops for the various kinds of probes, so this is
pretty straightforward (no allocation/deallocation issues).
gdb/ChangeLog:
* probe.h (probe_ops_cp): Remove typedef.
(DEF_VEC_P (probe_ops_cp)): Remove.
(all_probe_ops): Change type to std::vector.
* probe.c (info_probes_for_ops): Adjust to vector change.
(probe_linespec_to_ops): Likewise.
(all_probe_ops): Change type to std::vector.
(_initialize_probe): Adjust to vector change.
* dtrace-probe.c (_initialize_dtrace_probe): Likewise.
* elfread.c (elf_get_probes): Likewise.
* stap-probe.c (_initialize_stap_probe): Likewise.
This patch changes one usage of VEC to std::vector. It is a relatively
straightforward 1:1 change. The implementations of
sym_probe_fns::sym_get_probes return a borrowed reference to their probe
vectors, meaning that the caller should not free it. In the new code, I
made them return a const reference to the vector.
This patch and the following one were tested by the buildbot. I didn't
see any failures that looked related to this one.
gdb/ChangeLog:
* probe.h (struct probe_ops) <get_probes>: Change parameter from
vec to std::vector.
* probe.c (parse_probes_in_pspace): Update.
(find_probes_in_objfile): Update.
(find_probe_by_pc): Update.
(collect_probes): Update.
(probe_any_get_probes): Update.
* symfile.h (struct sym_probe_fns) <sym_get_probes> Change
return type to reference to std::vector.
* dtrace-probe.c (dtrace_process_dof_probe): Change parameter to
std::vector and update.
(dtrace_process_dof): Likewise.
(dtrace_get_probes): Likewise.
* elfread.c (elf_get_probes): Change return type to std::vector,
store an std::vector in bfd_data.
(probe_key_free): Update to std::vector.
* stap-probe.c (handle_stap_probe): Change parameter to
std::vector and update.
(stap_get_probes): Likewise.
* symfile-debug.c (debug_sym_get_probes): Change return type to
std::vector and update.
This renames a few functions -- skip_spaces_const,
skip_to_space_const, get_number_const, extract_arg_const -- to drop
the "_const" suffix and instead rely on overloading.
This makes future const fixes simpler by reducing the number of lines
that must be changed. I think it is also not any less clear, as all
these functions have the same interface as their non-const versions by
design. Furthermore there's an example of using an overload in-tree
already, namely check_for_argument.
This patch was largely created using some perl one-liners; then a few
fixes were applied by hand.
ChangeLog
2017-09-11 Tom Tromey <tom@tromey.com>
* common/common-utils.h (skip_to_space): Remove macro, redeclare
as function.
(skip_to_space): Rename from skip_to_space_const.
* common/common-utils.c (skip_to_space): New function.
(skip_to_space): Rename from skip_to_space_const.
* cli/cli-utils.h (get_number): Rename from get_number_const.
(extract_arg): Rename from extract_arg_const.
* cli/cli-utils.c (get_number): Rename from get_number_const.
(extract_arg): Rename from extract_arg_const.
(number_or_range_parser::get_number): Use ::get_number.
* aarch64-linux-tdep.c, ada-lang.c, arm-linux-tdep.c, ax-gdb.c,
break-catch-throw.c, breakpoint.c, cli/cli-cmds.c, cli/cli-dump.c,
cli/cli-script.c, cli/cli-setshow.c, compile/compile.c,
completer.c, demangle.c, disasm.c, findcmd.c, linespec.c,
linux-tdep.c, linux-thread-db.c, location.c, mi/mi-parse.c,
minsyms.c, nat/linux-procfs.c, printcmd.c, probe.c,
python/py-breakpoint.c, record.c, rust-exp.y, serial.c, stack.c,
stap-probe.c, tid-parse.c, tracepoint.c: Update all callers.
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.
ret->args_u.text is const char *, probe_args is const char *, so no cast
is needed. Found while doing cxx-conversion stuff, since it wouldn't
build in C++.
gdb/ChangeLog:
* stap-probe.c (handle_stap_probe): Remove unnecessary cast.
This patch improves the error reporting when handling SystemTap SDT
probes. "Handling", in this case, mostly means "parsing".
On gdb/probe.h, only trivial changes on functions' comments in order
to explicitly mention that some of them can throw exceptions. This is
just to make the API a bit more clear.
On gdb/stap-probe.c, I have s/internal_error/error/ on two functions
that are responsible for parsing specific bits of the probes'
arguments: stap_get_opcode and stap_get_expected_argument_type. It is
not correct to call internal_error on such situations because it is
not really GDB's fault if the probes have malformed arguments. I also
improved the error reported on stap_get_expected_argument_type by also
including the probe name on it.
Aside from that, and perhaps most importantly, I added a check on
stap_get_arg to make sure that we don't try to extract an argument
from a probe that has no arguments. This check issues an
internal_error, because it really means that GDB is doing something it
shouldn't.
Although it can be considered almost trivial, and despite the fact
that I am the maintainer for this part of the code, I am posting this
patch for review. I will wait a few days, and if nobody has anything
to say, I will go ahead and push it.
gdb/ChangeLog:
2015-09-01 Sergio Durigan Junior <sergiodj@redhat.com>
* probe.h (struct probe_ops) <get_probe_argument_count,
evaluate_probe_argument, enable_probe, disable_probe>: Mention in
the comment that the function can throw an exception.
(get_probe_argument_count): Likewise.
(evaluate_probe_argument): Likewise.
* stap-probe.c (stap_get_opcode): Call error instead of
internal_error.
(stap_get_expected_argument_type): Likewise. Add argument
'probe'. Improve error message by mentioning the probe's name.
(stap_parse_probe_arguments): Adjust call to
stap_get_expected_argument_type.
(stap_get_arg): Add comment. Assert that 'probe->args_parsed' is
not zero. Call internal_error if GDB requests an argument but the
probe has no arguments.
This patch adds the above-mentioned commands to the generic probe
abstraction implemented in probe.[ch]. The effects associated to
enabling or disabling a probe depend on the type of probe being
handled, and is triggered by invoking two back-end hooks in
`probe_ops'.
In case some particular probe type does not support the notion of
enabling and/or disabling, the corresponding fields on `probe_ops' can
be initialized to NULL. This is the case of SystemTap probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* stap-probe.c (stap_probe_ops): Add NULLs in the static
stap_probe_ops for `enable_probe' and `disable_probe'.
* probe.c (enable_probes_command): New function.
(disable_probes_command): Likewise.
(_initialize_probe): Define the cli commands `enable probe' and
`disable probe'.
(parse_probe_linespec): New function.
(info_probes_for_ops): Use parse_probe_linespec.
* probe.h (probe_ops): New hooks `enable_probe' and
`disable_probe'.
gdb/doc/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdb.texinfo (Static Probe Points): Cover the `enable probe' and
`disable probe' commands.
This patch moves the `compute_probe_arg' and `compile_probe_arg' functions
from stap-probe.c to probe.c. The rationale is that it is reasonable to
assume that all backends will provide the `$_probe_argN' convenience
variables, and that the user must be placed on the PC of the probe when
requesting that information. The value and type of the argument can still be
determined by the probe backend via the `pops->evaluate_probe_argument' and
`pops->compile_to_ax' handlers.
Note that a test in gdb.base/stap-probe.exp had to be adjusted because the "No
SystemTap probe at PC" messages are now "No probe at PC".
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* probe.c (compute_probe_arg): Moved from stap-probe.c
(compile_probe_arg): Likewise.
(probe_funcs): Likewise.
* stap-probe.c (compute_probe_arg): Moved to probe.c.
(compile_probe_arg): Likewise.
(probe_funcs): Likewise.
gdb/testsuite/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdb.base/stap-probe.exp (stap_test): Remove "SystemTap" from
expected message when trying to access $_probe_* convenience
variables while not on a probe.
A "probe type" (backend for the probe abstraction implemented in
probe.[ch]) can extend the information printed by `info probes' by
defining additional columns. This means that when `info probes' is
used to print all the probes regardless of their types, some of the
columns will be "not applicable" to some of the probes (like, say, the
Semaphore column only makes sense for SystemTap probes). This patch
makes `info probes' fill these slots with "n/a" marks (currently it
breaks the table) and not include headers for which no actual probe
has been found in the list of defined probes.
This patch also adds support for a new generic column "Type", that
displays the type of each probe. SystemTap probes identify themselves
as "stap" probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* probe.c (print_ui_out_not_applicables): New function.
(exists_probe_with_pops): Likewise.
(info_probes_for_ops): Do not include column headers for probe
types for which no probe has been actually found on any object.
Also invoke `print_ui_out_not_applicables' in order to match the
column rows with the header when probes of several types are
listed.
Print the "Type" column.
* probe.h (probe_ops): Added a new probe operation `type_name'.
* stap-probe.c (stap_probe_ops): Add `stap_type_name'.
(stap_type_name): New function.
In C, we can forward declare static structure instances. That doesn't
work in C++ though. C++ treats these as definitions. So then the
compiler complains about symbol redefinition, like:
src/gdb/elfread.c:1569:29: error: redefinition of ‘const sym_fns elf_sym_fns_lazy_psyms’
src/gdb/elfread.c:53:29: error: ‘const sym_fns elf_sym_fns_lazy_psyms’ previously declared here
The intent of static here is naturally to avoid making these objects
visible outside the compilation unit. The equivalent in C++ would be
to instead define the objects in the anonymous namespace. But given
that it's desirable to leave the codebase compiling as both C and C++
for a while, this just makes the objects extern.
(base_breakpoint_ops is already declared in breakpoint.h, so we can
just remove the forward declare from breakpoint.c)
gdb/ChangeLog:
2015-02-11 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
* breakpoint.c (base_breakpoint_ops): Delete.
* dwarf2loc.c (dwarf_expr_ctx_funcs): Make extern.
* elfread.c (elf_sym_fns_gdb_index, elf_sym_fns_lazy_psyms): Make extern.
* guile/guile.c (guile_extension_script_ops, guile_extension_ops): Make extern.
* ppcnbsd-tdep.c (ppcnbsd2_sigtramp): Make extern.
* python/py-arch.c (arch_object_type): Make extern.
* python/py-block.c (block_syms_iterator_object_type): Make extern.
* python/py-bpevent.c (breakpoint_event_object_type): Make extern.
* python/py-cmd.c (cmdpy_object_type): Make extern.
* python/py-continueevent.c (continue_event_object_type)
* python/py-event.h (GDBPY_NEW_EVENT_TYPE): Remove 'qual'
parameter. Update all callers.
* python/py-evtregistry.c (eventregistry_object_type): Make extern.
* python/py-exitedevent.c (exited_event_object_type): Make extern.
* python/py-finishbreakpoint.c (finish_breakpoint_object_type): Make extern.
* python/py-function.c (fnpy_object_type): Make extern.
* python/py-inferior.c (inferior_object_type, membuf_object_type): Make extern.
* python/py-infevents.c (call_pre_event_object_type)
(inferior_call_post_event_object_type).
(memory_changed_event_object_type): Make extern.
* python/py-infthread.c (thread_object_type): Make extern.
* python/py-lazy-string.c (lazy_string_object_type): Make extern.
* python/py-linetable.c (linetable_entry_object_type)
(linetable_object_type, ltpy_iterator_object_type): Make extern.
* python/py-newobjfileevent.c (new_objfile_event_object_type)
(clear_objfiles_event_object_type): Make extern.
* python/py-objfile.c (objfile_object_type): Make extern.
* python/py-param.c (parmpy_object_type): Make extern.
* python/py-progspace.c (pspace_object_type): Make extern.
* python/py-signalevent.c (signal_event_object_type): Make extern.
* python/py-symtab.c (symtab_object_type, sal_object_type): Make extern.
* python/py-type.c (type_object_type, field_object_type)
(type_iterator_object_type): Make extern.
* python/python.c (python_extension_script_ops)
(python_extension_ops): Make extern.
* stap-probe.c (stap_probe_ops): Make extern.
Joel contacted me offlist with a question about a warning that one of
his customers was seeing. The message came from the new
linker-debugger interface, which uses SDT probes internally. The
warning said:
(gdb) run
[...]
warning: Probes-based dynamic linker interface failed.
Reverting to original interface.
Argument to arithmetic operation not a number or boolean.
This should not have happened in the environment the customer was
using (RHEL-6.x), so I found it strange. Another thing caught my
attention: the last message, saying "Argument to arithmetic operation
not a number or boolean.".
Joel kindly investigated the issue further, and found the answer for
this. To quote him:
(gdb) set lang c
(gdb) p 48+$ebp
$4 = (void *) 0xffffd0f8
So far so good. But...
(gdb) set lang ada
(gdb) p 48+$ebp
Argument to arithmetic operation not a number or boolean.
Ooops! Interestingly, if you revert the order of the operands...
(gdb) p $ebp+48
$5 = (access void) 0xffffd0f8
So the problem is doing pointer arithmetics when the language is set
to Ada.
I remembered that, during the parsing and the evaluation of SDT probe
arguments, the code sets the language as current_language, because, at
that time, I thought it was not necessary to worry about the language
given that the code implements its own parser. I was wrong. So here
is a patch to fix that, by setting the language as C, which should
guarantee that the maths are done in the right way (TM).
It was somewhat hard to find a reproducer for this issue. In the end,
what I had to do was to create a testcase that used the %ebp register
on some displacement (e.g., "-4(%ebp)"), which finally triggered the
bug. I am not sure why I could not trigger it when using other
registers, but I did not want to spend too much time investigating
this issue, which seemed like an Ada issue. Also, because of this
peculiar way to trigger the problem, the testcase only covers x86-like
targets (i.e., i*86 and x86_64 with -m32).
Joel kindly tested this for me, and it worked. I also ran a full
regression test here on my Fedora 20 x86_64, and everything is fine.
I will push this patch in a few days if there are no comments.
gdb/ChangeLog:
2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com>
* stap-probe.c (stap_parse_argument): Initialize expout explicitly
using language_c, instead of current_language.
gdb/testsuite/ChangeLog:
2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.arch/stap-eval-lang-ada.S: Likewise.
* gdb.arch/stap-eval-lang-ada.c: Likewise.
* gdb.arch/stap-eval-lang-ada.exp: New file.
This patch is a fix to PR gdb/17235. The bug is about an unused
variable that got declared and set during one of the parsing phases of
an SDT probe's argument. I took the opportunity to rewrite some of the
code to improve the parsing. The bug was actually a thinko, because
what I wanted to do in the code was to discard the number on the string
being parsed.
During this portion, the code identifies that it is dealing with an
expression that begins with a sign ('+', '-' or '~'). This means that
the expression could be:
- a numeric literal (e.g., '+5')
- a register displacement (e.g., '-4(%rsp)')
- a subexpression (e.g., '-(2*3)')
So, after saving the sign and moving forward 1 char, now the code needs
to know if there is a digit followed by a register displacement prefix
operand (e.g., '(' on x86_64). If yes, then it is a register
operation. If not, then it will be handled recursively, and the code
will later apply the requested operation on the result (either a '+', a
'-' or a '~').
With the bug, the code was correctly discarding the digit (though using
strtol unnecessarily), but it wasn't properly dealing with
subexpressions when the register indirection prefix was '(', like on
x86_64. This patch also fixes this bug, and includes a testcase. It
passes on x86_64 Fedora 20.
This commit is actually an update to make the parser in
gdb/stap-probe.c be aware of all the possible prefixes that a probe
argument can have. According to the section "Argument Format" in:
<https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation>
The bitness of the arguments can be 8, 16, 32 or 64 bits, signed or
unsigned. Currently GDB recognizes only 32 and 64-bit arguments.
This commit extends this. It also provides a testcase, only for
x86_64 systems.
gdb/
2014-05-02 Sergio Durigan Junior <sergiodj@redhat.com>
* stap-probe.c (enum stap_arg_bitness): New enums to represent 8
and 16-bit signed and unsigned arguments. Update comment.
(stap_parse_probe_arguments): Extend code to handle such
arguments. Use warning instead of complaint to notify about
unrecognized bitness.
gdb/testsuite/
2014-05-02 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.arch/amd64-stap-optional-prefix.S (main): Add several
probes to test for bitness recognition.
* gdb.arch/amd64-stap-optional-prefix.exp
(test_probe_value_without_reg): New procedure.
Add code to test for different kinds of bitness.
This commit fixes PR breakpoints/16889, which is about a bug that
triggers when GDB tries to parse probes whose arguments do not contain
the initial (and optional) "N@" part. For reference sake, the de
facto format is described here:
<https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation>
Anyway, this PR actually uncovered two bugs (related) that were
happening while parsing the arguments. The first one was that the
parser *was* catching *some* arguments that were missing the "N@"
part, but it wasn't correctly setting the argument's type. This was
causing a NULL pointer being dereferenced, ouch...
The second bug uncovered was that the parser was not catching all of
the cases for a probe which did not provide the "N@" part. The fix
for that was to simplify the check that the code was making to
identify non-prefixed probes. The code is simpler and easier to read
now.
I am also providing a testcase for this bug, only for x86_64
architectures.
gdb/
2014-05-02 Sergio Durigan Junior <sergiodj@redhat.com>
PR breakpoints/16889
* stap-probe.c (stap_parse_probe_arguments): Simplify
check for non-prefixed probes (i.e., probes whose
arguments do not start with "N@"). Always set the
argument type to a sane value.
gdb/testsuite/
2014-05-02 Sergio Durigan Junior <sergiodj@redhat.com>
PR breakpoints/16889
* gdb.arch/amd64-stap-optional-prefix.S: New file.
* gdb.arch/amd64-stap-optional-prefix.exp: Likewise.
This patch moves the probe data from the objfile to the per-BFD
object. This lets the probes be shared between different inferiors
(and different objfiles when dlmopen is in use, should gdb ever handle
that).
2014-03-03 Tom Tromey <tromey@redhat.com>
* elfread.c (probe_key): Change to bfd_data.
(elf_get_probes, probe_key_free, _initialize_elfread): Probes are
now per-BFD, not per-objfile.
* stap-probe.c (stap_probe_destroy): Update comment.
(handle_stap_probe): Allocate on the per-BFD obstack.
This changes the probes to be independent of the program space.
After this, when a probe's address is needed, it is determined by
applying offsets at the point of use.
This introduces a bound_probe object, similar to bound minimal
symbols. Objects of this type are used when it's necessary to pass a
probe and its corresponding objfile.
This removes the backlink from probe to objfile, which was primarily
used to fetch the architecture to use.
This adds a get_probe_address function which calls a probe method to
compute the probe's relocated address. Similarly, it adds an objfile
parameter to the semaphore methods so they can do the relocation
properly as well.
2014-03-03 Tom Tromey <tromey@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Use bound probes.
* breakpoint.c (create_longjmp_master_breakpoint): Use
get_probe_address.
(add_location_to_breakpoint, bkpt_probe_insert_location)
(bkpt_probe_remove_location): Update.
* breakpoint.h (struct bp_location) <probe>: Now a bound_probe.
* elfread.c (elf_symfile_relocate_probe): Remove.
(elf_probe_fns): Update.
(insert_exception_resume_breakpoint): Change type of "probe"
parameter to bound_probe.
(check_exception_resume): Update.
* objfiles.c (objfile_relocate1): Don't relocate probes.
* probe.c (bound_probe_s): New typedef.
(parse_probes): Use get_probe_address. Set sal's objfile.
(find_probe_by_pc): Return a bound_probe.
(collect_probes): Return a VEC(bound_probe_s).
(compare_probes): Update.
(gen_ui_out_table_header_info): Change type of "probes"
parameter. Update.
(info_probes_for_ops): Update.
(get_probe_address): New function.
(probe_safe_evaluate_at_pc): Update.
* probe.h (struct probe_ops) <get_probe_address>: New field.
<set_semaphore, clear_semaphore>: Add objfile parameter.
(struct probe) <objfile>: Remove field.
<arch>: New field.
<address>: Update comment.
(struct bound_probe): New.
(find_probe_by_pc): Return a bound_probe.
(get_probe_address): Declare.
* solib-svr4.c (struct probe_and_action) <address>: New field.
(hash_probe_and_action, equal_probe_and_action): Update.
(register_solib_event_probe): Add address parameter.
(solib_event_probe_at): Update.
(svr4_create_probe_breakpoints): Add objfile parameter. Use
get_probe_address.
* stap-probe.c (struct stap_probe) <sem_addr>: Update comment.
(stap_get_probe_address): New function.
(stap_can_evaluate_probe_arguments, compute_probe_arg)
(compile_probe_arg): Update.
(stap_set_semaphore, stap_clear_semaphore): Compute semaphore's
address.
(handle_stap_probe): Don't relocate the probe.
(stap_relocate): Remove.
(stap_gen_info_probes_table_values): Update.
(stap_probe_ops): Remove stap_relocate.
* symfile-debug.c (debug_sym_relocate_probe): Remove.
(debug_sym_probe_fns): Update.
* symfile.h (struct sym_probe_fns) <sym_relocate_probe>: Remove.
* symtab.c (init_sal): Use memset.
* symtab.h (struct symtab_and_line) <objfile>: New field.
* tracepoint.c (start_tracing, stop_tracing): Update.
This patch does some basic cleanups on the SystemTap SDT probes API. It
removes spurious newlines, brackets, reindents some code, and do
explicit checks for NULL, NUL, and 0 where applicable.
2013-12-23 Sergio Durigan JUnior <sergiodj@redhat.com>
* stap-probe.c (struct stap_probe) <args_parsed>: Add comment.
(stap_is_generic_prefix): Delete extra brackets. Reindent.
(stap_parse_register_operand): Remove spurious newlines. Simplify
code to parse special token.
(stap_parse_argument_conditionally): Add gdb_assert.
(stap_parse_argument_1): Likewise. Explicitly check for NULL and
NUL.
(stap_parse_probe_arguments): Likewise.
(handle_stap_probe): Likewise. Reindent code.
(get_stap_base_address): Explicitly check for NULL.
(stap_get_probes): Likewise. Reindent code.
(stap_relocate): Explicitly check for 0.
(stap_gen_info_probes_table_values): Likewise.
This patch extends the current generic parser for SystemTap SDT probe
arguments. It can be almost considered a cleanup, but the main point of
it is actually to allow the generic parser to accept multiple prefixes
and suffixes for the its operands (i.e., integers, register names, and
register indirection).
I have chosen to implement this as a list of const strings, and declare
this list as "static" inside each target's method used to initialize
gdbarch.
This patch is actually a preparation for an upcoming patch for ARM,
which implements the support for multiple integer prefixes (as defined
by ARM's asm spec). And AArch64 will also need this, for the same
reason.
This patch was regtested on all architectures that it touches (i.e.,
i386, x86_64, ARM, PPC/PPC64, s390x and IA-64). No regressions were found.
2013-12-19 Sergio Durigan Junior <sergiodj@redhat.com>
* amd64-tdep.c (amd64_init_abi): Declare SystemTap SDT probe
argument prefixes and suffixes. Initialize gdbarch with them.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (stap_integer_prefix, stap_integer_suffix)
(stap_register_prefix, stap_register_suffix)
(stap_register_indirection_prefix)
(stap_register_indirection_suffix): Declare as "const char *const
*" instead of "const char *". Adjust printing function. Rename
all of the variables to the plural.
(pstring_list): New function.
* i386-tdep.c (i386_elf_init_abi): Declare SystemTap SDT probe
argument prefixes and suffixes. Initialize gdbarch with them.
* ia64-linux-tdep.c (ia64_linux_init_abi): Likewise.
* ppc-linux-tdep.c (ppc_linux_init_abi): Likewise.
* s390-linux-tdep.c (s390_gdbarch_init): Likewise.
* stap-probe.c (stap_is_generic_prefix): New function.
(stap_is_register_prefix): Likewise.
(stap_is_register_indirection_prefix): Likewise.
(stap_is_integer_prefix): Likewise.
(stap_generic_check_suffix): Likewise.
(stap_check_integer_suffix): Likewise.
(stap_check_register_suffix): Likewise.
(stap_check_register_indirection_suffix): Likewise.
(stap_parse_register_operand): Remove unecessary declarations for
variables holding prefix and suffix information. Use the new
functions listed above for checking for prefixes and suffixes.
(stap_parse_single_operand): Likewise.
This patch sanitizes the access to gdbarch made by various functions of
the SDT probe API. Before this patch, gdbarch was being accessed via
the probe's objfile; however, this proved to cause a bug on 32-bit ARM
targets because during the parsing of the probe's arguments the code
needed to access some pseudo-registers of the architecture, and this
information is not fully correct on the objfile's gdbarch.
Basically, the approach taken was to instead pass the current/selected
frame to the parsing and evaluation functions, so that they can extract
the gdbarch directly from the frame. It solved the ARM bug reported
above, and also contributed to make the API cleaner.
Tested on x86_64 and 32-bit ARM.
2013-12-11 Sergio Durigan Junior <sergiodj@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Pass selected frame
to get_probe_argument_count and evaluate_probe_argument.
* probe.c (get_probe_argument_count): Adjust declaration to accept
frame. Pass frame to probe_ops's get_probe_argument_count.
(evaluate_probe_argument): Likewise, for evaluate_probe_argument.
(probe_safe_evaluate_at_pc): Pass frame to
get_probe_argument_count and evaluate_probe_argument.
* probe.h (struct probe_ops) <get_probe_argument_count,
evaluate_probe_argument>: Adjust declarations to accept frame.
(get_probe_argument_count, evaluate_probe_argument): Likewise.
* solib-svr4.c (solib_event_probe_action): Get current frame.
Pass it to get_probe_argument_count.
(svr4_handle_solib_event): Get current frame. Pass it to
get_probe_argument_count and evaluate_probe_argument.
* stap-probe.c (stap_parse_probe_arguments): Adjust declaration to
accept gdbarch. Do not obtain it from the probe's objfile.
(stap_get_probe_argument_count): Adjust declaration to accept
frame. Obtain gdbarch from the frame. Call generic
can_evaluate_probe_arguments. Pass gdbarch to
stap_parse_probe_arguments.
(stap_get_arg): Adjust declaration to accept gdbarch. Pass it to
stap_parse_probe_arguments.
(stap_evaluate_probe_argument): Adjust declaration to accept
frame. Obtain gdbarch from the frame. Pass gdbarch to
stap_get_arg.
(stap_compile_to_ax): Pass agent_expr's gdbarch to stap_get_arg.
(compute_probe_arg): Obtain gdbarch from frame. Pass frame to
get_probe_argument_count and evaluate_probe_argument.
While looking into the probe API, it seemed to me that there were a
number of methods in sym_probe_fns that were not needed. This patch
removes them.
Specifically, it seems to me that sym_probe_fns ought to be concerned
with the API for constructing the probes. Any method relating to some
aspect of an individual probe can be handled via the probe's own
vtable. That is, the double indirection here doesn't seem useful --
it certainly isn't in fact used, but also I couldn't think of a
potential use.
2013-12-06 Tom Tromey <tromey@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Use
get_probe_argument_count and evaluate_probe_argument.
* elfread.c (elf_get_probe_argument_count)
(elf_can_evaluate_probe_arguments, elf_evaluate_probe_argument)
(elf_compile_to_ax): Remove.
(elf_probe_fns): Update.
* probe.c (get_probe_argument_count, can_evaluate_probe_arguments)
(evaluate_probe_argument): Call method on probe, not via sym
functions.
* stap-probe.c (compute_probe_arg): Use get_probe_argument_count,
evaluate_probe_argument.
(compile_probe_arg): Use get_probe_argument_count. Call method on
probe, not via sym functions.
* symfile-debug.c (debug_sym_get_probe_argument_count)
(debug_can_evaluate_probe_arguments)
(debug_sym_evaluate_probe_argument, debug_sym_compile_to_ax):
Remove.
(debug_sym_probe_fns): Remove.
* symfile.h (struct sym_probe_fns) <sym_get_probe_argument_count,
can_evaluate_probe_arguments, sym_evaluate_probe_argument,
sym_compile_to_ax>: Remove fields.
This moves the "gdbarch" field from the objfile into the BFD.
This field's value is derived from the BFD and is immutable over the
lifetime of the BFD. This makes it a reasonable candidate for pushing
into the per-BFD object.
This is part of the long-term objfile splitting project. In the long
run I think this patch will make it simpler to moves types from the
objfile to the per-BFD object; but the patch makes sense as a minor
cleanup by itself.
Built and regtested on x86-64 Fedora 18.
* cp-namespace.c (cp_lookup_symbol_imports_or_template): Use
get_objfile_arch.
* elfread.c (elf_rel_plt_read, elf_gnu_ifunc_record_cache)
(elf_gnu_ifunc_resolve_by_got): Use get_objfile_arch.
* jit.c (jit_object_close_impl): Update.
* jv-lang.c (get_dynamics_objfile): Update.
* linespec.c (add_minsym): Use get_dynamics_objfile.
* objfiles.c (get_objfile_bfd_data): Initialize 'gdbarch' field.
(allocate_objfile): Don't initialize 'gdbarch' field.
(get_objfile_arch): Update.
* objfiles.h (struct objfile_per_bfd_storage) <gdbarch>: New field,
moved from...
(struct objfile) <gdbarch>: ... here. Remove.
* stap-probe.c (stap_can_evaluate_probe_arguments): Use
get_objfile_arch.
* symfile.c (init_entry_point_info): Use get_objfile_arch.
* breakpoint.c (create_longjmp_master_breakpoint): Check if probe
interface can evaluate arguments. Fallback to the old mode if it
cannot.
(create_exception_master_breakpoint): Likewise.
* elfread.c (elf_can_evaluate_probe_arguments): New function.
(struct sym_probe_fns elf_probe_fns): Export function above to the
probe interface.
* probe.c (can_evaluate_probe_arguments): New function.
* probe.h (struct probe_ops) <can_evaluate_probe_arguments>: New
function pointer.
(can_evaluate_probe_arguments): New function prototype.
* solib-svr4.c (svr4_create_solib_event_breakpoints): Check if
probe interface can evaluate arguments. Fallback to the old mode
if it cannot.
* stap-probe.c (stap_get_probe_argument_count): Check if probe
interface can evaluate arguments. Warning the user if it cannot.
(stap_can_evaluate_probe_arguments): New function.
(struct probe_ops stap_probe_ops): Export function above to the
probe interface.
* symfile.h (struct sym_probe_fns) <can_evaluate_probe_arguments>:
New function pointer.
As a follow up to:
http://sourceware.org/ml/gdb-patches/2013-03/msg00449.html
In a nutshell, casts between 'char **' <-> 'unsigned char **' and
'char **' <-> 'const char **' are invalid.
I grepped for "\*\*) &" and found these. There's another one in
demangle.c, but I've split fixing that one to a separate patch.
I think the ada_decode_symbol change is perhaps the one that could be
surprising. The function's description has this comment, which makes
things much clearer:
The GSYMBOL parameter is "mutable" in the C++ sense: logically
const, but nevertheless modified to a semantically equivalent form
when a decoded name is cached in it. */
const char *
ada_decode_symbol (const struct general_symbol_info *gsymbol)
With that out of the way, I think the patch ends up being pretty
obvious.
Tested on x86_64 Fedora 17.
gdb/
2013-03-13 Pedro Alves <palves@redhat.com>
* ada-lang.c (ada_decode_symbol): Cast away constness of GSYMBOL
rather than casting 'const char * const *' to 'const char **'.
* ada-lex.l (processInt): Make "trailer" local const. Remove
'const char **' cast.
* arm-linux-tdep.c (arm_stap_parse_special_token): Add 'char *'
locals, and use those as strtol output pointer, instead than doing
invalid casts to from 'const char **' to 'char **'.
(_initialize_demangle): Remove cast.
* i386-tdep.c (i386_stap_parse_special_token): : Add 'char *'
locals, and use those as strtol output pointer, instead than doing
invalid casts to from 'const char **' to 'char **'.
* solib-dsbt.c (dsbt_get_initial_loadmaps): Remove 'gdb_byte**'
casts.
* stap-probe.c (stap_parse_register_operand)
(stap_parse_single_operand): Likewise.
$ make WERROR_CFLAGS="-Wpointer-sign -Werror" stap-probe.o 2>&1 1>/dev/null
../../src/gdb/stap-probe.c: In function ‘handle_stap_probe’:
../../src/gdb/stap-probe.c:1306:19: error: pointer targets in assignment differ in signedness [-Werror=pointer-sign]
cc1: all warnings being treated as errors
make: *** [stap-probe.o] Error 1
provider is a string, so it's rightfully a char*. 'data' holds raw
bytes (bfd_byte), so a cast is the right thing to do.
gdb/
2013-03-07 Pedro Alves <palves@redhat.com>
* stap-probe.c (handle_stap_probe): Add cast to char*.
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.
Tom Tromey