2014-08-07 17:29:19 +02:00
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/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
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2019-01-01 07:01:51 +01:00
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Copyright (C) 1986-2019 Free Software Foundation, Inc.
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2014-08-07 17:29:19 +02:00
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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2019-01-27 20:51:36 +01:00
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#ifndef COMMON_COMMON_EXCEPTIONS_H
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#define COMMON_COMMON_EXCEPTIONS_H
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2014-08-07 17:29:19 +02:00
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2016-04-12 18:20:04 +02:00
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#include <setjmp.h>
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gdb: Replace operator new / operator new[]
If xmalloc fails allocating memory, usually because something tried a
huge allocation, like xmalloc(-1) or some such, GDB asks the user what
to do:
.../src/gdb/utils.c:1079: internal-error: virtual memory exhausted.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
If the user says "n", that throws a QUIT exception, which is caught by
one of the multiple CATCH(RETURN_MASK_ALL) blocks somewhere up the
stack.
The default implementations of operator new / operator new[] call
malloc directly, and on memory allocation failure throw
std::bad_alloc. Currently, if that happens, since nothing catches it,
the exception escapes out of main, and GDB aborts from unhandled
exception.
This patch replaces the default operator new variants with versions
that, just like xmalloc:
#1 - Raise an internal-error on memory allocation failure.
#2 - Throw a QUIT gdb_exception, so that the exact same CATCH blocks
continue handling memory allocation problems.
A minor complication of #2 is that operator new can _only_ throw
std::bad_alloc, or something that extends it:
void* operator new (std::size_t size) throw (std::bad_alloc);
That means that if we let a gdb QUIT exception escape from within
operator new, the C++ runtime aborts due to unexpected exception
thrown.
So to bridge the gap, this patch adds a new gdb_quit_bad_alloc
exception type that inherits both std::bad_alloc and gdb_exception,
and throws _that_.
If we decide that we should be catching memory allocation errors in
fewer places than all the places we currently catch them (everywhere
we use RETURN_MASK_ALL currently), then we could change operator new
to throw plain std::bad_alloc then. But I'm considering such a change
as separate matter from this one -- it'd make sense to do the same to
xmalloc at the same time, for instance.
Meanwhile, this allows using new/new[] instead of xmalloc/XNEW/etc.
without losing the "virtual memory exhausted" internal-error
safeguard.
Tested on x86_64 Fedora 23.
gdb/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(COMMON_OBS): Add common/new-op.o.
(new-op.o): New rule.
* common/common-exceptions.h: Include <new>.
(struct gdb_quit_bad_alloc): New type.
* common/new-op.c: New file.
gdb/gdbserver/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(OBS): Add common/new-op.o.
(new-op.o): New rule.
2016-09-23 17:42:24 +02:00
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#include <new>
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Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
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#include <memory>
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Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
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#include <string>
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2014-08-07 17:29:19 +02:00
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/* Reasons for calling throw_exceptions(). NOTE: all reason values
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Eliminate catch_exceptions/catch_exceptions_with_msg
This patch gets rid of catch_exceptions / catch_exceptions_with_msg.
The latter is done mostly by getting rid of the three remaining
vestigial libgdb wrapper functions, which are really pointless
nowadays. This results in a good number of simplifications.
(I checked that Insight doesn't use those functions.)
The gdb.mi/mi-pthreads.exp change is necessary because this actually
fixes a bug, IMO -- the patch stops MI's -thread-select causing output
on the CLI stream.
I.e., before:
-thread-select 123456789
&"Thread ID 123456789 not known.\n"
^error,msg="Thread ID 123456789 not known."
(gdb)
After:
-thread-select 123456789
^error,msg="Thread ID 123456789 not known."
(gdb)
gdb/ChangeLog
2017-10-10 Pedro Alves <palves@redhat.com>
Tom Tromey <tom@tromey.com>
* breakpoint.c (struct captured_breakpoint_query_args)
(do_captured_breakpoint_query, gdb_breakpoint_query): Delete.
(print_breakpoint): New.
* breakpoint.h (print_breakpoint): Declare.
* common/common-exceptions.h (enum return_reason): Remove
references to catch_exceptions.
* exceptions.c (catch_exceptions, catch_exceptions_with_msg):
Delete.
* exceptions.h (catch_exceptions_ftype, catch_exceptions)
(catch_exception_ftype, catch_exceptions_with_msg): Delete.
* gdb.h: Delete.
* gdbthread.h (thread_select): Declare.
* mi/mi-cmd-break.c: Don't include gdb.h.
(breakpoint_notify): Use print_breakpoint.
* mi/mi-cmd-catch.c: Don't include gdb.h.
* mi/mi-interp.c: Don't include gdb.h.
(mi_print_breakpoint_for_event): New.
(mi_breakpoint_created, mi_breakpoint_modified): Use
mi_print_breakpoint_for_event.
* mi/mi-main.c: Don't include gdb.h.
(mi_cmd_thread_select): Parse the global thread ID here. Use
thread_select instead of gdb_thread_select.
(mi_cmd_thread_list_ids): Output "thread-ids" tuple here instead
of using gdb_list_thread_ids.
* remote-fileio.c (do_remote_fileio_request): Change type. Reply
FILEIO_ENOSYS here.
(remote_fileio_request): Use TRY/CATCH instead of
catch_exceptions.
* symfile-mem.c (struct symbol_file_add_from_memory_args)
(symbol_file_add_from_memory_wrapper): Delete.
(add_vsyscall_page): Use TRY/CATCH instead of catch_exceptions.
* thread.c: Don't include gdb.h.
(do_captured_list_thread_ids, gdb_list_thread_ids): Delete.
(thread_alive): Use thread_select.
(do_captured_thread_select): Delete, parts salvaged as ...
(thread_select): ... this new function.
(gdb_thread_select): Delete.
gdb/testsuite/ChangeLog
2017-10-10 Pedro Alves <palves@redhat.com>
* gdb.mi/mi-pthreads.exp (check_mi_thread_command_set): Don't
expect CLI output.
2017-10-10 17:45:51 +02:00
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must be different from zero. enum value 0 is reserved for internal
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use as the return value from an initial setjmp(). */
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2014-08-07 17:29:19 +02:00
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enum return_reason
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{
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/* User interrupt. */
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RETURN_QUIT = -2,
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/* Any other error. */
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RETURN_ERROR
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};
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#define RETURN_MASK(reason) (1 << (int)(-reason))
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typedef enum
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{
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RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT),
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RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR),
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RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR)
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} return_mask;
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/* Describe all exceptions. */
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enum errors {
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GDB_NO_ERROR,
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/* Any generic error, the corresponding text is in
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exception.message. */
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GENERIC_ERROR,
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/* Something requested was not found. */
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NOT_FOUND_ERROR,
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/* Thread library lacks support necessary for finding thread local
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storage. */
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TLS_NO_LIBRARY_SUPPORT_ERROR,
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/* Load module not found while attempting to find thread local storage. */
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TLS_LOAD_MODULE_NOT_FOUND_ERROR,
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/* Thread local storage has not been allocated yet. */
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TLS_NOT_ALLOCATED_YET_ERROR,
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/* Something else went wrong while attempting to find thread local
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storage. The ``struct gdb_exception'' message field provides
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more detail. */
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TLS_GENERIC_ERROR,
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/* Problem parsing an XML document. */
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XML_PARSE_ERROR,
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/* Error accessing memory. */
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MEMORY_ERROR,
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/* Value not available. E.g., a register was not collected in a
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traceframe. */
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NOT_AVAILABLE_ERROR,
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/* Value was optimized out. Note: if the value was a register, this
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means the register was not saved in the frame. */
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OPTIMIZED_OUT_ERROR,
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DWARF-5: call sites
this patch updates all call sites related DWARF-5 renames.
gdb/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* block.c (call_site_for_pc): Rename DW_OP_GNU_*, DW_TAG_GNU_* and
DW_AT_GNU_*.
* common/common-exceptions.h (enum errors): Likewise.
* dwarf2-frame.c (class dwarf_expr_executor): Likewise.
* dwarf2expr.c (dwarf_block_to_dwarf_reg)
(dwarf_expr_context::execute_stack_op): Likewise.
* dwarf2expr.h (struct dwarf_expr_context, struct dwarf_expr_piece):
Likewise.
* dwarf2loc.c (dwarf_evaluate_loc_desc::get_base_type)
(dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value)
(show_entry_values_debug, call_site_to_target_addr)
(func_addr_to_tail_call_list, func_verify_no_selftailcall)
(dwarf_expr_reg_to_entry_parameter, dwarf_entry_parameter_to_value)
(entry_data_value_free_closure, value_of_dwarf_reg_entry)
(value_of_dwarf_block_entry, indirect_pieced_value)
(symbol_needs_eval_context::push_dwarf_reg_entry_value):
(disassemble_dwarf_expression): Likewise.
* dwarf2read.c (process_die, inherit_abstract_dies)
(read_call_site_scope): Likewise.
* gdbtypes.h (struct func_type, struct call_site_parameter)
(struct call_site): Likewise.
* stack.c (read_frame_arg): Likewise.
* std-operator.def (OP_VAR_ENTRY_VALUE): Likewise.
gdb/doc/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.texinfo (Print Settings, Tail Call Frames): Rename DW_OP_GNU_*,
DW_TAG_GNU_* and DW_AT_GNU_*.
gdb/testsuite/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.arch/amd64-entry-value-param-dwarf5.S: New file.
* gdb.arch/amd64-entry-value-param-dwarf5.c: New file.
* gdb.arch/amd64-entry-value-param-dwarf5.exp: New file.
* gdb.arch/amd64-entry-value.exp: Rename DW_OP_GNU_*, DW_TAG_GNU_* and
DW_AT_GNU_*.
2017-02-20 20:53:21 +01:00
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/* DW_OP_entry_value resolving failed. */
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2014-08-07 17:29:19 +02:00
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NO_ENTRY_VALUE_ERROR,
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/* Target throwing an error has been closed. Current command should be
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aborted as the inferior state is no longer valid. */
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TARGET_CLOSE_ERROR,
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/* An undefined command was executed. */
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UNDEFINED_COMMAND_ERROR,
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/* Requested feature, method, mechanism, etc. is not supported. */
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NOT_SUPPORTED_ERROR,
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2015-02-01 00:07:22 +01:00
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/* The number of candidates generated during line completion has
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reached the user's specified limit. This isn't an error, this exception
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is used to halt searching for more completions, but for consistency
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"_ERROR" is appended to the name. */
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MAX_COMPLETIONS_REACHED_ERROR,
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2014-08-07 17:29:19 +02:00
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/* Add more errors here. */
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NR_ERRORS
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};
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struct gdb_exception
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{
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Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
gdb_exception ()
|
|
|
|
: reason ((enum return_reason) 0),
|
|
|
|
error (GDB_NO_ERROR)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
gdb_exception (enum return_reason r, enum errors e)
|
|
|
|
: reason (r),
|
|
|
|
error (e)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
|
|
|
gdb_exception (enum return_reason r, enum errors e,
|
|
|
|
const char *fmt, va_list ap)
|
|
|
|
ATTRIBUTE_PRINTF (4, 0)
|
|
|
|
: reason (r),
|
|
|
|
error (e),
|
|
|
|
message (std::make_shared<std::string> (string_vprintf (fmt, ap)))
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
Make exception handling more efficient
This makes exception handling more efficient in a few spots, through
the use of const- and rvalue-references.
I wrote this patch by commenting out the gdb_exception copy
constructor and then examining the resulting error messages one by
one, introducing the use of std::move where appropriate.
gdb/ChangeLog
2019-04-25 Tom Tromey <tromey@adacore.com>
* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
rvalue reference.
(gdb_xml_start_element_wrapper, gdb_xml_end_element_wrapper)
(gdb_xml_parser::parse): Use std::move.
* python/python-internal.h (gdbpy_convert_exception): Take a const
reference.
* python/py-value.c (valpy_getitem, valpy_nonzero): Use
std::move.
* python/py-utils.c (gdbpy_convert_exception): Take a const
reference.
* python/py-inferior.c (infpy_write_memory, infpy_search_memory):
Use std::move.
* python/py-breakpoint.c (bppy_set_condition, bppy_set_commands):
Use std::move.
* mi/mi-main.c (mi_print_exception): Take a const reference.
* main.c (handle_command_errors): Take a const reference.
* linespec.c (parse_linespec): Use std::move.
* infcall.c (run_inferior_call): Use std::move.
(call_function_by_hand_dummy): Use std::move.
* exec.c (try_open_exec_file): Use std::move.
* exceptions.h (exception_print, exception_fprintf)
(exception_print_same): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Change parameters to
const reference.
* event-top.c (gdb_rl_callback_read_char_wrapper): Update.
* common/new-op.c: Use std::move.
* common/common-exceptions.h (struct gdb_exception): Add move
constructor.
(struct gdb_exception_error, struct gdb_exception_quit, struct
gdb_quit_bad_alloc): Change constructor to move constructor.
(throw_exception): Change parameter to rvalue reference.
* common/common-exceptions.c (throw_exception): Take rvalue
reference.
* cli/cli-interp.c (safe_execute_command): Use std::move.
* breakpoint.c (insert_bp_location, location_to_sals): Use
std::move.
2019-04-24 14:50:06 +02:00
|
|
|
/* The move constructor exists so that we can mark it "noexcept",
|
|
|
|
which is a good practice for any sort of exception object. */
|
|
|
|
explicit gdb_exception (gdb_exception &&other) noexcept = default;
|
|
|
|
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
/* The copy constructor exists so that we can mark it "noexcept",
|
|
|
|
which is a good practice for any sort of exception object. */
|
|
|
|
gdb_exception (const gdb_exception &other) noexcept
|
|
|
|
: reason (other.reason),
|
|
|
|
error (other.error),
|
|
|
|
message (other.message)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
/* The assignment operator exists so that we can mark it "noexcept",
|
|
|
|
which is a good practice for any sort of exception object. */
|
|
|
|
gdb_exception &operator= (const gdb_exception &other) noexcept
|
|
|
|
{
|
|
|
|
reason = other.reason;
|
|
|
|
error = other.error;
|
|
|
|
message = other.message;
|
|
|
|
return *this;
|
|
|
|
}
|
|
|
|
|
2019-04-23 15:29:49 +02:00
|
|
|
gdb_exception &operator= (gdb_exception &&other) noexcept = default;
|
|
|
|
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
/* Return the contents of the exception message, as a C string. The
|
|
|
|
string remains owned by the exception object. */
|
|
|
|
const char *what () const noexcept
|
|
|
|
{
|
|
|
|
return message->c_str ();
|
|
|
|
}
|
|
|
|
|
2014-08-07 17:29:19 +02:00
|
|
|
enum return_reason reason;
|
|
|
|
enum errors error;
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
std::shared_ptr<std::string> message;
|
2014-08-07 17:29:19 +02:00
|
|
|
};
|
|
|
|
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
/* Functions to drive the sjlj-based exceptions state machine. Though
|
|
|
|
declared here by necessity, these functions should be considered
|
|
|
|
internal to the exceptions subsystem and not used other than via
|
|
|
|
the TRY/CATCH (or TRY_SJLJ/CATCH_SJLJ) macros defined below. */
|
2014-08-07 17:29:19 +02:00
|
|
|
|
2016-04-12 18:20:04 +02:00
|
|
|
extern jmp_buf *exceptions_state_mc_init (void);
|
2014-08-07 17:29:19 +02:00
|
|
|
extern int exceptions_state_mc_action_iter (void);
|
|
|
|
extern int exceptions_state_mc_action_iter_1 (void);
|
Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
2015-03-07 16:14:14 +01:00
|
|
|
extern int exceptions_state_mc_catch (struct gdb_exception *, int);
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
|
2014-08-07 17:29:19 +02:00
|
|
|
/* Macro to wrap up standard try/catch behavior.
|
|
|
|
|
|
|
|
The double loop lets us correctly handle code "break"ing out of the
|
|
|
|
try catch block. (It works as the "break" only exits the inner
|
|
|
|
"while" loop, the outer for loop detects this handling it
|
|
|
|
correctly.) Of course "return" and "goto" are not so lucky.
|
|
|
|
|
|
|
|
For instance:
|
|
|
|
|
|
|
|
*INDENT-OFF*
|
|
|
|
|
2019-01-28 18:29:42 +01:00
|
|
|
TRY_SJLJ
|
2014-08-07 17:29:19 +02:00
|
|
|
{
|
|
|
|
}
|
2019-01-28 18:29:42 +01:00
|
|
|
CATCH_SJLJ (e, RETURN_MASK_ERROR)
|
2014-08-07 17:29:19 +02:00
|
|
|
{
|
Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
2015-03-07 16:14:14 +01:00
|
|
|
switch (e.reason)
|
|
|
|
{
|
|
|
|
case RETURN_ERROR: ...
|
|
|
|
}
|
2014-08-07 17:29:19 +02:00
|
|
|
}
|
2019-01-28 18:29:42 +01:00
|
|
|
END_CATCH_SJLJ
|
2014-08-07 17:29:19 +02:00
|
|
|
|
2019-01-28 18:29:42 +01:00
|
|
|
The SJLJ variants are needed in some cases where gdb exceptions
|
|
|
|
need to cross third-party library code compiled without exceptions
|
|
|
|
support (e.g., readline). */
|
2014-08-07 17:29:19 +02:00
|
|
|
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
#define TRY_SJLJ \
|
2014-08-07 17:29:19 +02:00
|
|
|
{ \
|
2016-04-12 18:20:04 +02:00
|
|
|
jmp_buf *buf = \
|
Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
2015-03-07 16:14:14 +01:00
|
|
|
exceptions_state_mc_init (); \
|
2016-04-12 18:20:04 +02:00
|
|
|
setjmp (*buf); \
|
2014-08-07 17:29:19 +02:00
|
|
|
} \
|
|
|
|
while (exceptions_state_mc_action_iter ()) \
|
|
|
|
while (exceptions_state_mc_action_iter_1 ())
|
|
|
|
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
#define CATCH_SJLJ(EXCEPTION, MASK) \
|
Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
2015-03-07 16:14:14 +01:00
|
|
|
{ \
|
|
|
|
struct gdb_exception EXCEPTION; \
|
|
|
|
if (exceptions_state_mc_catch (&(EXCEPTION), MASK))
|
|
|
|
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
#define END_CATCH_SJLJ \
|
Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
2015-03-07 16:14:14 +01:00
|
|
|
}
|
|
|
|
|
Make TRY/CATCH use real C++ try/catch in C++ mode
Although the current TRY/CATCH implementation works in C++ mode too,
it relies on setjmp/longjmp, and longjmp bypasses calling the
destructors of objects on the stack, which is obviously bad for C++.
This patch fixes this by makes TRY/CATCH use real try/catch in C++
mode behind the scenes. The way this is done allows RAII and cleanups
to coexist while we phase out cleanups, instead of requiring a flag
day.
This patch is not strictly necessary until we require a C++ compiler
and start actually using RAII, though I'm all for baby steps, and it
shows my proposed way forward. Putting it in now, allows for easier
experimentation and exposure of potential problems with real C++
exceptions.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c [!__cplusplus] (enum catcher_state)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't define.
[__cplusplus] (try_scope_depth): New global.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, gdb_exception_sliced_copy)
(exception_rethrow): New functions.
(throw_exception): In C++ mode, throw
gdb_exception_RETURN_MASK_QUIT for RETURN_QUIT and
gdb_exception_RETURN_MASK_ERROR for RETURN_ERROR.
(throw_it): In C++ mode, use try_scope_depth.
* common/common-exceptions.h [!__cplusplus]
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't declare.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, exception_rethrow): Declare.
[__cplusplus] (struct exception_try_scope): New struct.
[__cplusplus] (TRY, CATCH, END_CATCH): Reimplement on top of real
C++ exceptions.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): New types.
2015-03-07 15:50:03 +01:00
|
|
|
/* The exception types client code may catch. They're just shims
|
|
|
|
around gdb_exception that add nothing but type info. Which is used
|
|
|
|
is selected depending on the MASK argument passed to CATCH. */
|
|
|
|
|
2019-04-03 23:59:07 +02:00
|
|
|
struct gdb_exception_error : public gdb_exception
|
Make TRY/CATCH use real C++ try/catch in C++ mode
Although the current TRY/CATCH implementation works in C++ mode too,
it relies on setjmp/longjmp, and longjmp bypasses calling the
destructors of objects on the stack, which is obviously bad for C++.
This patch fixes this by makes TRY/CATCH use real try/catch in C++
mode behind the scenes. The way this is done allows RAII and cleanups
to coexist while we phase out cleanups, instead of requiring a flag
day.
This patch is not strictly necessary until we require a C++ compiler
and start actually using RAII, though I'm all for baby steps, and it
shows my proposed way forward. Putting it in now, allows for easier
experimentation and exposure of potential problems with real C++
exceptions.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c [!__cplusplus] (enum catcher_state)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't define.
[__cplusplus] (try_scope_depth): New global.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, gdb_exception_sliced_copy)
(exception_rethrow): New functions.
(throw_exception): In C++ mode, throw
gdb_exception_RETURN_MASK_QUIT for RETURN_QUIT and
gdb_exception_RETURN_MASK_ERROR for RETURN_ERROR.
(throw_it): In C++ mode, use try_scope_depth.
* common/common-exceptions.h [!__cplusplus]
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't declare.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, exception_rethrow): Declare.
[__cplusplus] (struct exception_try_scope): New struct.
[__cplusplus] (TRY, CATCH, END_CATCH): Reimplement on top of real
C++ exceptions.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): New types.
2015-03-07 15:50:03 +01:00
|
|
|
{
|
Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
|
|
|
gdb_exception_error (enum errors e, const char *fmt, va_list ap)
|
|
|
|
ATTRIBUTE_PRINTF (3, 0)
|
|
|
|
: gdb_exception (RETURN_ERROR, e, fmt, ap)
|
2019-01-28 18:56:58 +01:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
Make exception handling more efficient
This makes exception handling more efficient in a few spots, through
the use of const- and rvalue-references.
I wrote this patch by commenting out the gdb_exception copy
constructor and then examining the resulting error messages one by
one, introducing the use of std::move where appropriate.
gdb/ChangeLog
2019-04-25 Tom Tromey <tromey@adacore.com>
* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
rvalue reference.
(gdb_xml_start_element_wrapper, gdb_xml_end_element_wrapper)
(gdb_xml_parser::parse): Use std::move.
* python/python-internal.h (gdbpy_convert_exception): Take a const
reference.
* python/py-value.c (valpy_getitem, valpy_nonzero): Use
std::move.
* python/py-utils.c (gdbpy_convert_exception): Take a const
reference.
* python/py-inferior.c (infpy_write_memory, infpy_search_memory):
Use std::move.
* python/py-breakpoint.c (bppy_set_condition, bppy_set_commands):
Use std::move.
* mi/mi-main.c (mi_print_exception): Take a const reference.
* main.c (handle_command_errors): Take a const reference.
* linespec.c (parse_linespec): Use std::move.
* infcall.c (run_inferior_call): Use std::move.
(call_function_by_hand_dummy): Use std::move.
* exec.c (try_open_exec_file): Use std::move.
* exceptions.h (exception_print, exception_fprintf)
(exception_print_same): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Change parameters to
const reference.
* event-top.c (gdb_rl_callback_read_char_wrapper): Update.
* common/new-op.c: Use std::move.
* common/common-exceptions.h (struct gdb_exception): Add move
constructor.
(struct gdb_exception_error, struct gdb_exception_quit, struct
gdb_quit_bad_alloc): Change constructor to move constructor.
(throw_exception): Change parameter to rvalue reference.
* common/common-exceptions.c (throw_exception): Take rvalue
reference.
* cli/cli-interp.c (safe_execute_command): Use std::move.
* breakpoint.c (insert_bp_location, location_to_sals): Use
std::move.
2019-04-24 14:50:06 +02:00
|
|
|
explicit gdb_exception_error (gdb_exception &&ex) noexcept
|
|
|
|
: gdb_exception (std::move (ex))
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
{
|
Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
|
|
|
gdb_assert (ex.reason == RETURN_ERROR);
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
}
|
Make TRY/CATCH use real C++ try/catch in C++ mode
Although the current TRY/CATCH implementation works in C++ mode too,
it relies on setjmp/longjmp, and longjmp bypasses calling the
destructors of objects on the stack, which is obviously bad for C++.
This patch fixes this by makes TRY/CATCH use real try/catch in C++
mode behind the scenes. The way this is done allows RAII and cleanups
to coexist while we phase out cleanups, instead of requiring a flag
day.
This patch is not strictly necessary until we require a C++ compiler
and start actually using RAII, though I'm all for baby steps, and it
shows my proposed way forward. Putting it in now, allows for easier
experimentation and exposure of potential problems with real C++
exceptions.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c [!__cplusplus] (enum catcher_state)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't define.
[__cplusplus] (try_scope_depth): New global.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, gdb_exception_sliced_copy)
(exception_rethrow): New functions.
(throw_exception): In C++ mode, throw
gdb_exception_RETURN_MASK_QUIT for RETURN_QUIT and
gdb_exception_RETURN_MASK_ERROR for RETURN_ERROR.
(throw_it): In C++ mode, use try_scope_depth.
* common/common-exceptions.h [!__cplusplus]
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't declare.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, exception_rethrow): Declare.
[__cplusplus] (struct exception_try_scope): New struct.
[__cplusplus] (TRY, CATCH, END_CATCH): Reimplement on top of real
C++ exceptions.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): New types.
2015-03-07 15:50:03 +01:00
|
|
|
};
|
|
|
|
|
2019-04-03 23:59:07 +02:00
|
|
|
struct gdb_exception_quit : public gdb_exception
|
Make TRY/CATCH use real C++ try/catch in C++ mode
Although the current TRY/CATCH implementation works in C++ mode too,
it relies on setjmp/longjmp, and longjmp bypasses calling the
destructors of objects on the stack, which is obviously bad for C++.
This patch fixes this by makes TRY/CATCH use real try/catch in C++
mode behind the scenes. The way this is done allows RAII and cleanups
to coexist while we phase out cleanups, instead of requiring a flag
day.
This patch is not strictly necessary until we require a C++ compiler
and start actually using RAII, though I'm all for baby steps, and it
shows my proposed way forward. Putting it in now, allows for easier
experimentation and exposure of potential problems with real C++
exceptions.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c [!__cplusplus] (enum catcher_state)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't define.
[__cplusplus] (try_scope_depth): New global.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, gdb_exception_sliced_copy)
(exception_rethrow): New functions.
(throw_exception): In C++ mode, throw
gdb_exception_RETURN_MASK_QUIT for RETURN_QUIT and
gdb_exception_RETURN_MASK_ERROR for RETURN_ERROR.
(throw_it): In C++ mode, use try_scope_depth.
* common/common-exceptions.h [!__cplusplus]
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't declare.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, exception_rethrow): Declare.
[__cplusplus] (struct exception_try_scope): New struct.
[__cplusplus] (TRY, CATCH, END_CATCH): Reimplement on top of real
C++ exceptions.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): New types.
2015-03-07 15:50:03 +01:00
|
|
|
{
|
Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
|
|
|
gdb_exception_quit (const char *fmt, va_list ap)
|
|
|
|
ATTRIBUTE_PRINTF (2, 0)
|
|
|
|
: gdb_exception (RETURN_QUIT, GDB_NO_ERROR, fmt, ap)
|
2019-01-28 18:56:58 +01:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
Make exception handling more efficient
This makes exception handling more efficient in a few spots, through
the use of const- and rvalue-references.
I wrote this patch by commenting out the gdb_exception copy
constructor and then examining the resulting error messages one by
one, introducing the use of std::move where appropriate.
gdb/ChangeLog
2019-04-25 Tom Tromey <tromey@adacore.com>
* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
rvalue reference.
(gdb_xml_start_element_wrapper, gdb_xml_end_element_wrapper)
(gdb_xml_parser::parse): Use std::move.
* python/python-internal.h (gdbpy_convert_exception): Take a const
reference.
* python/py-value.c (valpy_getitem, valpy_nonzero): Use
std::move.
* python/py-utils.c (gdbpy_convert_exception): Take a const
reference.
* python/py-inferior.c (infpy_write_memory, infpy_search_memory):
Use std::move.
* python/py-breakpoint.c (bppy_set_condition, bppy_set_commands):
Use std::move.
* mi/mi-main.c (mi_print_exception): Take a const reference.
* main.c (handle_command_errors): Take a const reference.
* linespec.c (parse_linespec): Use std::move.
* infcall.c (run_inferior_call): Use std::move.
(call_function_by_hand_dummy): Use std::move.
* exec.c (try_open_exec_file): Use std::move.
* exceptions.h (exception_print, exception_fprintf)
(exception_print_same): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Change parameters to
const reference.
* event-top.c (gdb_rl_callback_read_char_wrapper): Update.
* common/new-op.c: Use std::move.
* common/common-exceptions.h (struct gdb_exception): Add move
constructor.
(struct gdb_exception_error, struct gdb_exception_quit, struct
gdb_quit_bad_alloc): Change constructor to move constructor.
(throw_exception): Change parameter to rvalue reference.
* common/common-exceptions.c (throw_exception): Take rvalue
reference.
* cli/cli-interp.c (safe_execute_command): Use std::move.
* breakpoint.c (insert_bp_location, location_to_sals): Use
std::move.
2019-04-24 14:50:06 +02:00
|
|
|
explicit gdb_exception_quit (gdb_exception &&ex) noexcept
|
|
|
|
: gdb_exception (std::move (ex))
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
{
|
Some gdb_exception{,error,quit} tweaks
- Explicitly include <string> for std::string.
- Use std::make_shared to construct gdb_exception::message instead of
operator new, avoiding one heap allocation (2 instead of 3). Add
'const char *fmt, va_list ap' parameters to
gdb_exception{,error,quit}'s ctors, and do the std::make_shared in
the gdb_exception ctor.
- gdb_exception_error's constructor does not need to have an 'enum
return_reason' parameter, since it is always RETURN_ERROR, by
definition.
- Similarly, gdb_exception_quit's contructor does not need to have
'enum return_reason'/'enum errors' parameters.
- In the gdb_exception_{quit,_error} ctors that take a gdb_exception
as argument, assert that they're being passed a gdb_exception object
of the right 'reason'.
gdb/ChangeLog:
2019-04-08 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (throw_exception): Don't create
named object to throw; throw directly.
(throw_it): Likewise. Don't initialize gdb_exception::message
here, with new; pass FMT and AP to the ctor instead.
* common/common-exceptions.h: Include <string>.
(gdb_exception::gdb_exception(enum return_reason, enum errors,
const char *, va_list)): New ctor. Use std::make_shared.
(gdb_exception_error::gdb_exception_error(enum return_reason, enum
errors)): Delete.
(gdb_exception_error::gdb_exception_error(enum errors, const char
*, va_list)): New.
(gdb_exception_error::gdb_exception_error(const gdb_exception &)):
Add assertion.
(gdb_exception_quit::gdb_exception_quit(enum return_reason, enum
errors)): Delete.
(gdb_exception_quit::gdb_exception_quit(const char *, va_list)): New.
(gdb_exception_quit::gdb_exception_quit(const gdb_exception &)):
Add assertion.
2019-04-08 14:03:54 +02:00
|
|
|
gdb_assert (ex.reason == RETURN_QUIT);
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
}
|
Make TRY/CATCH use real C++ try/catch in C++ mode
Although the current TRY/CATCH implementation works in C++ mode too,
it relies on setjmp/longjmp, and longjmp bypasses calling the
destructors of objects on the stack, which is obviously bad for C++.
This patch fixes this by makes TRY/CATCH use real try/catch in C++
mode behind the scenes. The way this is done allows RAII and cleanups
to coexist while we phase out cleanups, instead of requiring a flag
day.
This patch is not strictly necessary until we require a C++ compiler
and start actually using RAII, though I'm all for baby steps, and it
shows my proposed way forward. Putting it in now, allows for easier
experimentation and exposure of potential problems with real C++
exceptions.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c [!__cplusplus] (enum catcher_state)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't define.
[__cplusplus] (try_scope_depth): New global.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, gdb_exception_sliced_copy)
(exception_rethrow): New functions.
(throw_exception): In C++ mode, throw
gdb_exception_RETURN_MASK_QUIT for RETURN_QUIT and
gdb_exception_RETURN_MASK_ERROR for RETURN_ERROR.
(throw_it): In C++ mode, use try_scope_depth.
* common/common-exceptions.h [!__cplusplus]
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Don't declare.
[__cplusplus] (exception_try_scope_entry)
(exception_try_scope_exit, exception_rethrow): Declare.
[__cplusplus] (struct exception_try_scope): New struct.
[__cplusplus] (TRY, CATCH, END_CATCH): Reimplement on top of real
C++ exceptions.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): New types.
2015-03-07 15:50:03 +01:00
|
|
|
};
|
|
|
|
|
gdb: Replace operator new / operator new[]
If xmalloc fails allocating memory, usually because something tried a
huge allocation, like xmalloc(-1) or some such, GDB asks the user what
to do:
.../src/gdb/utils.c:1079: internal-error: virtual memory exhausted.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
If the user says "n", that throws a QUIT exception, which is caught by
one of the multiple CATCH(RETURN_MASK_ALL) blocks somewhere up the
stack.
The default implementations of operator new / operator new[] call
malloc directly, and on memory allocation failure throw
std::bad_alloc. Currently, if that happens, since nothing catches it,
the exception escapes out of main, and GDB aborts from unhandled
exception.
This patch replaces the default operator new variants with versions
that, just like xmalloc:
#1 - Raise an internal-error on memory allocation failure.
#2 - Throw a QUIT gdb_exception, so that the exact same CATCH blocks
continue handling memory allocation problems.
A minor complication of #2 is that operator new can _only_ throw
std::bad_alloc, or something that extends it:
void* operator new (std::size_t size) throw (std::bad_alloc);
That means that if we let a gdb QUIT exception escape from within
operator new, the C++ runtime aborts due to unexpected exception
thrown.
So to bridge the gap, this patch adds a new gdb_quit_bad_alloc
exception type that inherits both std::bad_alloc and gdb_exception,
and throws _that_.
If we decide that we should be catching memory allocation errors in
fewer places than all the places we currently catch them (everywhere
we use RETURN_MASK_ALL currently), then we could change operator new
to throw plain std::bad_alloc then. But I'm considering such a change
as separate matter from this one -- it'd make sense to do the same to
xmalloc at the same time, for instance.
Meanwhile, this allows using new/new[] instead of xmalloc/XNEW/etc.
without losing the "virtual memory exhausted" internal-error
safeguard.
Tested on x86_64 Fedora 23.
gdb/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(COMMON_OBS): Add common/new-op.o.
(new-op.o): New rule.
* common/common-exceptions.h: Include <new>.
(struct gdb_quit_bad_alloc): New type.
* common/new-op.c: New file.
gdb/gdbserver/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(OBS): Add common/new-op.o.
(new-op.o): New rule.
2016-09-23 17:42:24 +02:00
|
|
|
/* An exception type that inherits from both std::bad_alloc and a gdb
|
|
|
|
exception. This is necessary because operator new can only throw
|
|
|
|
std::bad_alloc, and OTOH, we want exceptions thrown due to memory
|
|
|
|
allocation error to be caught by all the CATCH/RETURN_MASK_ALL
|
|
|
|
spread around the codebase. */
|
|
|
|
|
|
|
|
struct gdb_quit_bad_alloc
|
2019-04-03 23:59:07 +02:00
|
|
|
: public gdb_exception_quit,
|
gdb: Replace operator new / operator new[]
If xmalloc fails allocating memory, usually because something tried a
huge allocation, like xmalloc(-1) or some such, GDB asks the user what
to do:
.../src/gdb/utils.c:1079: internal-error: virtual memory exhausted.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
If the user says "n", that throws a QUIT exception, which is caught by
one of the multiple CATCH(RETURN_MASK_ALL) blocks somewhere up the
stack.
The default implementations of operator new / operator new[] call
malloc directly, and on memory allocation failure throw
std::bad_alloc. Currently, if that happens, since nothing catches it,
the exception escapes out of main, and GDB aborts from unhandled
exception.
This patch replaces the default operator new variants with versions
that, just like xmalloc:
#1 - Raise an internal-error on memory allocation failure.
#2 - Throw a QUIT gdb_exception, so that the exact same CATCH blocks
continue handling memory allocation problems.
A minor complication of #2 is that operator new can _only_ throw
std::bad_alloc, or something that extends it:
void* operator new (std::size_t size) throw (std::bad_alloc);
That means that if we let a gdb QUIT exception escape from within
operator new, the C++ runtime aborts due to unexpected exception
thrown.
So to bridge the gap, this patch adds a new gdb_quit_bad_alloc
exception type that inherits both std::bad_alloc and gdb_exception,
and throws _that_.
If we decide that we should be catching memory allocation errors in
fewer places than all the places we currently catch them (everywhere
we use RETURN_MASK_ALL currently), then we could change operator new
to throw plain std::bad_alloc then. But I'm considering such a change
as separate matter from this one -- it'd make sense to do the same to
xmalloc at the same time, for instance.
Meanwhile, this allows using new/new[] instead of xmalloc/XNEW/etc.
without losing the "virtual memory exhausted" internal-error
safeguard.
Tested on x86_64 Fedora 23.
gdb/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(COMMON_OBS): Add common/new-op.o.
(new-op.o): New rule.
* common/common-exceptions.h: Include <new>.
(struct gdb_quit_bad_alloc): New type.
* common/new-op.c: New file.
gdb/gdbserver/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(OBS): Add common/new-op.o.
(new-op.o): New rule.
2016-09-23 17:42:24 +02:00
|
|
|
public std::bad_alloc
|
|
|
|
{
|
Make exception handling more efficient
This makes exception handling more efficient in a few spots, through
the use of const- and rvalue-references.
I wrote this patch by commenting out the gdb_exception copy
constructor and then examining the resulting error messages one by
one, introducing the use of std::move where appropriate.
gdb/ChangeLog
2019-04-25 Tom Tromey <tromey@adacore.com>
* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
rvalue reference.
(gdb_xml_start_element_wrapper, gdb_xml_end_element_wrapper)
(gdb_xml_parser::parse): Use std::move.
* python/python-internal.h (gdbpy_convert_exception): Take a const
reference.
* python/py-value.c (valpy_getitem, valpy_nonzero): Use
std::move.
* python/py-utils.c (gdbpy_convert_exception): Take a const
reference.
* python/py-inferior.c (infpy_write_memory, infpy_search_memory):
Use std::move.
* python/py-breakpoint.c (bppy_set_condition, bppy_set_commands):
Use std::move.
* mi/mi-main.c (mi_print_exception): Take a const reference.
* main.c (handle_command_errors): Take a const reference.
* linespec.c (parse_linespec): Use std::move.
* infcall.c (run_inferior_call): Use std::move.
(call_function_by_hand_dummy): Use std::move.
* exec.c (try_open_exec_file): Use std::move.
* exceptions.h (exception_print, exception_fprintf)
(exception_print_same): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Change parameters to
const reference.
* event-top.c (gdb_rl_callback_read_char_wrapper): Update.
* common/new-op.c: Use std::move.
* common/common-exceptions.h (struct gdb_exception): Add move
constructor.
(struct gdb_exception_error, struct gdb_exception_quit, struct
gdb_quit_bad_alloc): Change constructor to move constructor.
(throw_exception): Change parameter to rvalue reference.
* common/common-exceptions.c (throw_exception): Take rvalue
reference.
* cli/cli-interp.c (safe_execute_command): Use std::move.
* breakpoint.c (insert_bp_location, location_to_sals): Use
std::move.
2019-04-24 14:50:06 +02:00
|
|
|
explicit gdb_quit_bad_alloc (gdb_exception &&ex) noexcept
|
|
|
|
: gdb_exception_quit (std::move (ex)),
|
Make exceptions use std::string and be self-managing
This changes the exception's "message" member to be a shared_ptr
wrapping a std::string. This allows removing the stack of exception
messages, because now exceptions will self-destruct when needed. This
also adds a noexcept copy constructor and operator= to gdb_exception,
plus a "what" method.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c (gdb_xml_parser::parse): Update.
* x86-linux-nat.c (x86_linux_nat_target::enable_btrace): Update.
* value.c (show_convenience): Update.
* unittests/cli-utils-selftests.c (test_number_or_range_parser)
(test_parse_flags_qcs): Update.
* thread.c (thr_try_catch_cmd): Update.
* target.c (target_translate_tls_address): Update.
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(info_frame_command_core, frame_apply_command_count): Update.
* rust-exp.y (rust_lex_exception_test): Update.
* riscv-tdep.c (riscv_print_one_register_info): Update.
* remote.c (remote_target::enable_btrace): Update.
* record-btrace.c (record_btrace_enable_warn): Update.
* python/py-utils.c (gdbpy_convert_exception): Update.
* printcmd.c (do_one_display, print_variable_and_value): Update.
* mi/mi-main.c (mi_print_exception): Update.
* mi/mi-interp.c (mi_cmd_interpreter_exec): Use SCOPE_EXIT.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* linux-nat.c (linux_nat_target::attach): Update.
* linux-fork.c (class scoped_switch_fork_info): Update.
* infrun.c (displaced_step_prepare): Update.
* infcall.c (call_function_by_hand_dummy): Update.
* guile/scm-exception.c (gdbscm_scm_from_gdb_exception): Update.
* gnu-v3-abi.c (print_one_vtable): Update.
* frame.c (get_prev_frame_always): Update.
* f-valprint.c (info_common_command_for_block): Update.
* exec.c (try_open_exec_file): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Update.
* dwarf2-frame.c (dwarf2_build_frame_info): Update.
* dwarf-index-cache.c (index_cache::store)
(index_cache::lookup_gdb_index): Update.
* darwin-nat.c (maybe_cache_shell): Update.
* cp-valprint.c (cp_print_value_fields): Update.
* compile/compile-cplus-symbols.c (gcc_cplus_convert_symbol)
(gcc_cplus_symbol_address): Update.
* compile/compile-c-symbols.c (gcc_convert_symbol)
(gcc_symbol_address, generate_c_for_for_one_variable): Update.
* common/selftest.c: Update.
* common/common-exceptions.h (struct gdb_exception) <message>: Now
a std::string.
(exception_try_scope_entry, exception_try_scope_exit): Don't
declare.
(struct exception_try_scope): Remove.
(TRY): Don't use exception_try_scope.
(struct gdb_exception): Add constructor, operator=.
<what>: New method.
(struct gdb_exception_RETURN_MASK_ALL)
(struct gdb_exception_RETURN_MASK_ERROR)
(struct gdb_exception_RETURN_MASK_QUIT): Add constructor.
(struct gdb_quit_bad_alloc): Update.
* common/common-exceptions.c (exception_none): Change
initializer.
(struct catcher) <state, exception>: Initialize inline.
<prev>: Remove member.
(current_catcher): Remove.
(catchers): New global.
(exceptions_state_mc_init): Simplify.
(catcher_pop): Remove.
(exceptions_state_mc, exceptions_state_mc_catch): Update.
(try_scope_depth, exception_try_scope_entry)
(exception_try_scope_exit): Remove.
(throw_exception_sjlj): Update.
(exception_messages, exception_messages_size): Remove.
(throw_it): Simplify.
(gdb_exception_sliced_copy): Remove.
(throw_exception_cxx): Update.
* cli/cli-script.c (script_from_file): Update.
* breakpoint.c (insert_bp_location, update_breakpoint_locations):
Update.
* ada-valprint.c (ada_val_print): Update.
* ada-lang.c (ada_to_fixed_type_1, ada_exception_name_addr)
(create_excep_cond_exprs): Update.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c (handle_btrace_general_set, handle_qxfer_btrace)
(handle_qxfer_btrace_conf, detach_or_kill_for_exit_cleanup)
(captured_main, main): Update.
* gdbreplay.c (main): Update.
2019-01-28 18:11:10 +01:00
|
|
|
std::bad_alloc ()
|
gdb: Replace operator new / operator new[]
If xmalloc fails allocating memory, usually because something tried a
huge allocation, like xmalloc(-1) or some such, GDB asks the user what
to do:
.../src/gdb/utils.c:1079: internal-error: virtual memory exhausted.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
If the user says "n", that throws a QUIT exception, which is caught by
one of the multiple CATCH(RETURN_MASK_ALL) blocks somewhere up the
stack.
The default implementations of operator new / operator new[] call
malloc directly, and on memory allocation failure throw
std::bad_alloc. Currently, if that happens, since nothing catches it,
the exception escapes out of main, and GDB aborts from unhandled
exception.
This patch replaces the default operator new variants with versions
that, just like xmalloc:
#1 - Raise an internal-error on memory allocation failure.
#2 - Throw a QUIT gdb_exception, so that the exact same CATCH blocks
continue handling memory allocation problems.
A minor complication of #2 is that operator new can _only_ throw
std::bad_alloc, or something that extends it:
void* operator new (std::size_t size) throw (std::bad_alloc);
That means that if we let a gdb QUIT exception escape from within
operator new, the C++ runtime aborts due to unexpected exception
thrown.
So to bridge the gap, this patch adds a new gdb_quit_bad_alloc
exception type that inherits both std::bad_alloc and gdb_exception,
and throws _that_.
If we decide that we should be catching memory allocation errors in
fewer places than all the places we currently catch them (everywhere
we use RETURN_MASK_ALL currently), then we could change operator new
to throw plain std::bad_alloc then. But I'm considering such a change
as separate matter from this one -- it'd make sense to do the same to
xmalloc at the same time, for instance.
Meanwhile, this allows using new/new[] instead of xmalloc/XNEW/etc.
without losing the "virtual memory exhausted" internal-error
safeguard.
Tested on x86_64 Fedora 23.
gdb/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(COMMON_OBS): Add common/new-op.o.
(new-op.o): New rule.
* common/common-exceptions.h: Include <new>.
(struct gdb_quit_bad_alloc): New type.
* common/new-op.c: New file.
gdb/gdbserver/ChangeLog:
2016-09-23 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add common/new-op.c.
(OBS): Add common/new-op.o.
(new-op.o): New rule.
2016-09-23 17:42:24 +02:00
|
|
|
{
|
|
|
|
}
|
|
|
|
};
|
|
|
|
|
2014-08-07 17:29:19 +02:00
|
|
|
/* *INDENT-ON* */
|
|
|
|
|
2016-10-06 20:23:37 +02:00
|
|
|
/* Throw an exception (as described by "struct gdb_exception"),
|
|
|
|
landing in the inner most containing exception handler established
|
|
|
|
using TRY/CATCH. */
|
Make exception handling more efficient
This makes exception handling more efficient in a few spots, through
the use of const- and rvalue-references.
I wrote this patch by commenting out the gdb_exception copy
constructor and then examining the resulting error messages one by
one, introducing the use of std::move where appropriate.
gdb/ChangeLog
2019-04-25 Tom Tromey <tromey@adacore.com>
* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
rvalue reference.
(gdb_xml_start_element_wrapper, gdb_xml_end_element_wrapper)
(gdb_xml_parser::parse): Use std::move.
* python/python-internal.h (gdbpy_convert_exception): Take a const
reference.
* python/py-value.c (valpy_getitem, valpy_nonzero): Use
std::move.
* python/py-utils.c (gdbpy_convert_exception): Take a const
reference.
* python/py-inferior.c (infpy_write_memory, infpy_search_memory):
Use std::move.
* python/py-breakpoint.c (bppy_set_condition, bppy_set_commands):
Use std::move.
* mi/mi-main.c (mi_print_exception): Take a const reference.
* main.c (handle_command_errors): Take a const reference.
* linespec.c (parse_linespec): Use std::move.
* infcall.c (run_inferior_call): Use std::move.
(call_function_by_hand_dummy): Use std::move.
* exec.c (try_open_exec_file): Use std::move.
* exceptions.h (exception_print, exception_fprintf)
(exception_print_same): Update.
* exceptions.c (print_exception, exception_print)
(exception_fprintf, exception_print_same): Change parameters to
const reference.
* event-top.c (gdb_rl_callback_read_char_wrapper): Update.
* common/new-op.c: Use std::move.
* common/common-exceptions.h (struct gdb_exception): Add move
constructor.
(struct gdb_exception_error, struct gdb_exception_quit, struct
gdb_quit_bad_alloc): Change constructor to move constructor.
(throw_exception): Change parameter to rvalue reference.
* common/common-exceptions.c (throw_exception): Take rvalue
reference.
* cli/cli-interp.c (safe_execute_command): Use std::move.
* breakpoint.c (insert_bp_location, location_to_sals): Use
std::move.
2019-04-24 14:50:06 +02:00
|
|
|
extern void throw_exception (gdb_exception &&exception)
|
2014-08-07 17:29:19 +02:00
|
|
|
ATTRIBUTE_NORETURN;
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
|
|
|
|
/* Throw an exception by executing a LONG JUMP to the inner most
|
2016-10-06 20:23:37 +02:00
|
|
|
containing exception handler established using TRY_SJLJ. Necessary
|
|
|
|
in some cases where we need to throw GDB exceptions across
|
|
|
|
third-party library code (e.g., readline). */
|
2019-04-23 15:29:49 +02:00
|
|
|
extern void throw_exception_sjlj (const struct gdb_exception &exception)
|
Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH
If we map GDB'S TRY/CATCH macros to C++ try/catch, GDB breaks on
systems where readline isn't built with exceptions support. The
problem is that readline calls into GDB through the callback
interface, and if GDB's callback throws a C++ exception/error, the
system unwinder won't manage to unwind past the readline frame, and
ends up calling std::terminate(), which aborts the process:
(gdb) whatever-command-that-causes-an-error
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
Aborted
$
This went unnoticed for so long because:
- the x86-64 ABI requires -fasynchronous-unwind-tables, making it
possible for exceptions to cross readline with no special handling.
But e.g., on ARM or AIX, unless you build readline with
-fexceptions, you trip on the problem.
- TRY/CATCH was mapped to setjmp/longjmp, even in C++ mode, until
quite recently.
The fix is to catch and save any GDB exception that is thrown inside
the GDB readline callback, and then once the callback returns back to
the GDB code that called into readline in the first place, rethrow the
saved GDB exception.
This is similar in spirit to how we catch/map GDB exceptions at the
GDB/Python and GDB/Guile API boundaries.
The next question is then: if we intercept all exceptions within GDB's
readline callback, should we simply return normally to readline? The
callback prototype has no way to signal an error back to readline (*).
The answer is no -- if we return normally, we'll be returning to a
loop inside rl_callback_read_char that continues processing pending
input, calling into GDB again, redisplaying the prompt, etc. Thus if
we want to error out of rl_callback_read_char, we need to long jump
across it, just like we always did before TRY/CATCH were ever mapped
to C++ exceptions.
My first approach built a specialized API to handle this, with a
couple macros to hide the setjmp/longjmp and the struct gdb_exception
saving/rethrowing.
However, I realized that we need to:
- Handle multiple active rl_callback_read_char invocations. If,
while processing input something triggers a secondary prompt, we
end up in a nested rl_callback_read_char call, through
gdb_readline_wrapper.
- Propagate a struct gdb_exception along with the longjmp.
... and that this is exactly what the setjmp/longjmp-based TRY/CATCH
does.
So the fix makes the setjmp/longjmp TRY/CATCH always available under
new TRY_SJLJ/CATCH_SJLJ aliases, even when TRY/CATCH is mapped to C++
try/catch, and then uses TRY_SJLJ/CATCH_SJLJ to propagate GDB
exceptions across the readline callback.
This turns out to be a much better looking fix than my bespoke API
attempt, even. We'll probably be able to simplify TRY_SJLJ/CATCH_SJLJ
when we finally get rid of TRY/CATCH all over the tree, but until
then, this reuse seems quite nice for avoiding a second parallel
setjmp/longjmp mechanism.
(*) - maybe we could propose a readline API change, but we still need
to handle current readline, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (enum catcher_state, struct catcher)
(current_catcher): Define in C++ mode too.
(exceptions_state_mc_catch): Call throw_exception_sjlj instead of
throw_exception.
(throw_exception_sjlj, throw_exception_cxx): New functions,
factored out from throw_exception.
(throw_exception): Reimplement.
* common/common-exceptions.h (exceptions_state_mc_init)
(exceptions_state_mc_action_iter)
(exceptions_state_mc_action_iter_1, exceptions_state_mc_catch):
Declare in C++ mode too.
(TRY): Rename to ...
(TRY_SJLJ): ... this.
(CATCH): Rename to ...
(CATCH_SJLJ): ... this.
(END_CATCH): Rename to ...
(END_CATCH_SJLJ): ... this.
[GDB_XCPT == GDB_XCPT_SJMP] (TRY, CATCH, END_CATCH): Map to SJLJ
equivalents.
(throw_exception): Update comments.
(throw_exception_sjlj): Declare.
* event-top.c (gdb_rl_callback_read_char_wrapper): Extend intro
comment. Wrap body in TRY_SJLJ/CATCH_SJLJ and rethrow any
intercepted exception.
(gdb_rl_callback_handler): New function.
(gdb_rl_callback_handler_install): Always install
gdb_rl_callback_handler as readline callback.
2016-04-22 17:18:33 +02:00
|
|
|
ATTRIBUTE_NORETURN;
|
|
|
|
|
|
|
|
/* Convenience wrappers around throw_exception that throw GDB
|
|
|
|
errors. */
|
2014-08-07 17:29:19 +02:00
|
|
|
extern void throw_verror (enum errors, const char *fmt, va_list ap)
|
|
|
|
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
|
|
|
|
extern void throw_vquit (const char *fmt, va_list ap)
|
|
|
|
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
|
|
|
|
extern void throw_error (enum errors error, const char *fmt, ...)
|
|
|
|
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
|
|
|
|
extern void throw_quit (const char *fmt, ...)
|
|
|
|
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
|
|
|
|
|
2019-01-27 20:51:36 +01:00
|
|
|
#endif /* COMMON_COMMON_EXCEPTIONS_H */
|