OpenE2K/binutils-gdb
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4 Commits

Author SHA1 Message Date
Joel Brobecker
42a4f53d2b Update copyright year range in all GDB files. 
This commit applies all changes made after running the gdb/copyright.py
script.

Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.

gdb/ChangeLog:

	Update copyright year range in all GDB files.
 2019-01-01 10:01:51 +04:00
Joel Brobecker
e2882c8578 Update copyright year range in all GDB files 
gdb/ChangeLog:

        Update copyright year range in all GDB files
 2018-01-02 07:38:06 +04:00
Pedro Alves
d5722aa2fe Introduce gdb::byte_vector, add allocator that default-initializes 
In some cases we've been replacing heap-allocated gdb_byte buffers
managed with xmalloc/make_cleanup(xfree) with gdb::vector<gdb_byte>.
That usually pessimizes the code a little bit because std::vector
value-initializes elements (which for gdb_byte means
zero-initialization), while if you're creating a temporary buffer,
you're most certaintly going to fill it in with some data.  An
alternative is to use

  unique_ptr<gdb_byte[]> buf (new gdb_byte[size]);

but it looks like that's not very popular.

Recently, a use of obstacks in dwarf2read.c was replaced with
std::vector<gdb_byte> and that as well introduced a pessimization for
always memsetting the buffer when it's garanteed that the zeros will
be overwritten immediately.  (see dwarf2read.c change in this patch to
find it.)

So here's a different take at addressing this issue "by design":

#1 - Introduce default_init_allocator<T>

I.e., a custom allocator that does default construction using default
initialization, meaning, no more zero initialization.  That's the
default_init_allocation<T> class added in this patch.

See "Notes" at
<http://en.cppreference.com/w/cpp/container/vector/resize>.

#2 - Introduce def_vector<T>

I.e., a convenience typedef, because typing the allocator is annoying:

  using def_vector<T> = std::vector<T, gdb::default_init_allocator<T>>;

#3 - Introduce byte_vector

Because gdb_byte vectors will be the common thing, add a convenience
"byte_vector" typedef:

  using byte_vector = def_vector<gdb_byte>;

which is really the same as:

  std::vector<gdb_byte, gdb::default_init_allocator<gdb_byte>>;

The intent then is to make "gdb::byte_vector" be the go-to for dynamic
byte buffers.  So the less friction, the better.

#4 - Adjust current code to use it.

To set the example going forward.  Replace std::vector uses and also
unique_ptr<byte[]> uses.

One nice thing is that with this allocator, for changes like these:

  -std::unique_ptr<byte[]> buf (new gdb_byte[some_size]);
  +gdb::byte_vector buf (some_size);
   fill_with_data (buf.data (), buf.size ());

the generated code is the same as before.  I.e., the compiler
de-structures the vector and gets rid of the unused "reserved vs size"
related fields.

The other nice thing is that it's easier to write
  gdb::byte_vector buf (size);
than
  std::unique_ptr<gdb_byte[]> buf (new gdb_byte[size]);
or even (C++14):
  auto buf = std::make_unique<gdb_byte[]> (size); // zero-initializes...

#5 - Suggest s/std::vector<gdb_byte>/gdb::byte_vector/ going forward.

Note that this commit actually fixes a couple of bugs where the current
code is incorrectly using "std::vector::reserve(new_size)" and then
accessing the vector's internal buffer beyond the vector's size: see
dwarf2loc.c and charset.c.  That's undefined behavior and may trigger
debug mode assertion failures.  With default_init_allocator,
"resize()" behaves like "reserve()" performance wise, in that it
leaves new elements with unspecified values, but, it does that safely
without triggering undefined behavior when you access those values.

gdb/ChangeLog:
2017-06-14  Pedro Alves  <palves@redhat.com>

	* ada-lang.c: Include "common/byte-vector.h".
	(ada_value_primitive_packed_val): Use gdb::byte_vector.
	* charset.c (wchar_iterator::iterate): Resize the vector instead
	of reserving it.
	* common/byte-vector.h: Include "common/def-vector.h".
	(wchar_iterator::m_out): Now a gdb::def_vector<gdb_wchar_t>.
	* cli/cli-dump.c: Include "common/byte-vector.h".
	(dump_memory_to_file, restore_binary_file): Use gdb::byte_vector.
	* common/byte-vector.h: New file.
	* common/def-vector.h: New file.
	* common/default-init-alloc.h: New file.
	* dwarf2loc.c: Include "common/byte-vector.h".
	(rw_pieced_value): Use gdb::byte_vector, and resize the vector
	instead of reserving it.
	* dwarf2read.c: Include "common/byte-vector.h".
	(data_buf::m_vec): Now a gdb::byte_vector.
	* gdb_regex.c: Include "common/def-vector.h".
	(compiled_regex::compiled_regex): Use gdb::def_vector<char>.
	* mi/mi-main.c: Include "common/byte-vector.h".
	(mi_cmd_data_read_memory): Use gdb::byte_vector.
	* printcmd.c: Include "common/byte-vector.h".
	(print_scalar_formatted): Use gdb::byte_vector.
	* valprint.c: Include "common/byte-vector.h".
	(maybe_negate_by_bytes, print_decimal_chars): Use
	gdb::byte_vector.
 2017-06-14 11:08:52 +01:00
Pedro Alves
2d7cc5c797 Introduce compiled_regex, eliminate make_regfree_cleanup 
This patch replaces compile_rx_or_error and make_regfree_cleanup with
a class that wraps a regex_t.

gdb/ChangeLog:
2017-06-07  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SFILES): Add gdb_regex.c.
	(COMMON_OBS): Add gdb_regex.o.
	* ada-lang.c (ada_add_standard_exceptions)
	(ada_add_exceptions_from_frame, name_matches_regex)
	(ada_add_global_exceptions, ada_exceptions_list_1): Change regex
	parameter type to compiled_regex.  Adjust.
	(ada_exceptions_list): Use compiled_regex.
	* break-catch-throw.c (exception_catchpoint::pattern): Now a
	std::unique_ptr<compiled_regex>.
	(exception_catchpoint::~exception_catchpoint): Remove regfree
	call.
	(check_status_exception_catchpoint): Adjust to use compiled_regex.
	(handle_gnu_v3_exceptions): Adjust to use compiled_regex.
	* breakpoint.c (solib_catchpoint::compiled): Now a
	std::unique_ptr<compiled_regex>.
	(solib_catchpoint::~solib_catchpoint): Remove regfree call.
	(check_status_catch_solib): Adjust to use compiled_regex.
	(add_solib_catchpoint): Adjust to use compiled_regex.
	* cli/cli-cmds.c (apropos_command): Use compiled_regex.
	* cli/cli-decode.c (apropos_cmd): Change regex parameter to
	compiled_regex reference.  Adjust to use it.
	* cli/cli-decode.h: Remove struct re_pattern_buffer forward
	declaration.  Include "gdb_regex.h".
	(apropos_cmd): Change regex parameter to compiled_regex reference.
	* gdb_regex.c: New file.
	* gdb_regex.h (make_regfree_cleanup, get_regcomp_error): Delete
	declarations.
	(class compiled_regex): New.
	* linux-tdep.c: Include "common/gdb_optional.h".
	(struct mapping_regexes): New, factored out from
	mapping_is_anonymous_p, and adjusted to use compiled_regex.
	(mapping_is_anonymous_p): Use mapping_regexes wrapped in a
	gdb::optional and remove cleanups.  Adjust to compiled_regex.
	* probe.c: Include "common/gdb_optional.h".
	(collect_probes): Use compiled_regex and gdb::optional and remove
	cleanups.
	* skip.c: Include "common/gdb_optional.h".
	(skiplist_entry::compiled_function_regexp): Now a
	gdb::optional<compiled_regex>.
	(skiplist_entry::compiled_function_regexp_is_valid): Delete field.
	(free_skiplist_entry): Remove regfree call.
	(compile_skip_regexp, skip_rfunction_p): Adjust to use
	compiled_regex and gdb::optional.
	* symtab.c: Include "common/gdb_optional.h".
	(search_symbols): Use compiled_regex and gdb::optional.
	* utils.c (do_regfree_cleanup, make_regfree_cleanup)
	(get_regcomp_error, compile_rx_or_error): Delete.  Some bits moved
	to gdb_regex.c.
 2017-06-07 14:21:40 +01:00