This moves dwarf2_cu and one supporting data structure to a new header
file.  The main goal, as always with this kind of change, is to make
the DWARF reader a bit more understandable.

gdb/ChangeLog
2021-05-17  Tom Tromey  <tom@tromey.com>

	* Makefile.in (HFILES_NO_SRCDIR): Add dwarf2/cu.h.
	* dwarf2/read.c (struct delayed_method_info, struct dwarf2_cu):
	Move to cu.h.
	* dwarf2/cu.h: New file.

Two additional settings for developers who use emacs:

  1. Set brace-list-open to 0 for C and C++ modes, this ensures we
  format things like:

  enum blah
  {
    ....
  };

  Instead of the default for the emacs GNU style:

  enum blah
    {
      ...
    };

  The former seems to be the GDB style.

  2. Set sentence-end-double-space to t.  This is actually the default
  value for this setting, but if anyone has customised this to nil in
  general, then forcing this back to t for GDB files will give a
  better behaviour for the paragraph filling.

gdb/ChangeLog:

	* .dir-locals.el: Set sentence-end-double-space for all modes, and
	set brace-list-open to 0 for C and C++ modes.

gdbserver/ChangeLog:

	* .dir-locals.el: Set sentence-end-double-space for all modes, and
	set brace-list-open to 0 for C and C++ modes.

gdbsupport/ChangeLog:

	* .dir-locals.el: Set sentence-end-double-space for all modes, and
	set brace-list-open to 0 for C and C++ modes.

With GCC trunk, gdb.ada/access_to_packed_array.exp causes a GDB crash.
The problem is that ptype tries to resolve a dynamic type.  However,
the inferior is not running, so there are no frames.

This patch updates dwarf2_evaluate_loc_desc::get_frame_base to handle
this situation.

gdb/ChangeLog
2021-05-17  Tom Tromey  <tromey@adacore.com>

	* dwarf2/loc.c (dwarf2_evaluate_loc_desc::get_frame_base): Throw
	if frame is null.

I tried a build using the undefined behavior sanitizer, and gcc gave
this error:

In file included from /usr/include/string.h:495,
                 from ../gnulib/import/string.h:41,
                 from ../../binutils-gdb/gdb/../gdbsupport/common-defs.h:95,
                 from ../../binutils-gdb/gdb/nat/linux-osdata.c:20:
In function 'char* strncpy(char*, const char*, size_t)',
    inlined from 'void time_from_time_t(char*, int, TIME_T)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:923:15,
    inlined from 'void time_from_time_t(char*, int, TIME_T)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:911:1,
    inlined from 'void linux_xfer_osdata_sem(buffer*)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:1082:22:
/usr/include/bits/string_fortified.h:106:34: error: 'char* __builtin_strncpy(char*, const char*, long unsigned int)' specified bound 32 equals destination size [-Werror=stringop-truncation]

This patch fixes the problem by subtracting one from the length
parameter to strncpy.

I changed a couple of other similar functions -- gcc does not warn
about these, but I didn't see any substantial difference between the
different cases, and I think these are just latent warnings, to be
triggered in the future by a change to inlining heuristics.

gdb/ChangeLog
2021-05-17  Tom Tromey  <tromey@adacore.com>

	* nat/linux-osdata.c (user_from_uid, time_from_time_t)
	(group_from_gid): Subtract one from strncpy length.

Address sanitizer pointed out a buglet in source.c:add_path.
In this test, from gdb.base/source-dir.exp:

    (gdb) set directories :/foo:/bar

... 'p[-1]' will result in a buffer underflow.
This patch fixes the bug by introducing a new check.

2021-05-17  Tom Tromey  <tromey@adacore.com>

	* source.c (add_path): Check 'p' before using 'p[-1]'.

Address sanitizer pointed out that the patch to use 'delete' for
dwarf2_per_cu_data introduced a bug -- now it is possible to delete a
signatured_type using a pointer to its base class.

This patch fixes the problem by introducing a deleter and a unique_ptr
specialization.  A virtual destructor would be more ordinary here, but
it seemed wasteful to add a vtable just for this purpose.  If virtual
methods are ever needed here, we can revisit this.

2021-05-17  Tom Tromey  <tromey@adacore.com>

	* dwarf2/read.h (struct dwarf2_per_cu_data_deleter: New.
	(dwarf2_per_cu_data_up): New typedef.
	(struct dwarf2_per_bfd) <allocate_per_cu>: Change return type.
	<all_comp_units>: Use dwarf2_per_cu_data_up.
	* dwarf2/read.c (dwarf2_per_cu_data::operator()): New function.
	(dwarf2_per_bfd::allocate_per_cu): Return dwarf2_per_cu_data_up.
	(create_cu_from_index_list): Likewise.
	(create_signatured_type_table_from_index)
	(create_cus_from_debug_names_list, add_type_unit)
	(read_comp_units_from_section): Update.
	(dwarf2_find_containing_comp_unit): Change type of all_comp_units.
	(run_test): Update.

I noticed that sort_tu_by_abbrev_offset only has a single caller.  It
seemed simpler to replace it with an implementation of operator<
instead.

2021-05-17  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (tu_abbrev_offset::operator<): New method.
	(sort_tu_by_abbrev_offset): Remove.
	(build_type_psymtabs): Update.

I noticed these files because they weren't considered by black for
reformatting, prior to adding pyproject.toml, because their extension is
not .py.  I don't think they specifically need to be named .py.in, so I
suggest renaming them to .py.  This will make it nicer to edit them, as
editors will recognize them more easily as Python files.

Perhaps this was needed before, when the testsuite didn't always put
output files in the output directory.  Then, a different name for the
source and destination file might have been desirable to avoid
overwriting a file with itself (perhaps that wasn't well handled).  But
in any case, it doesn't see to cause any problem now.

gdb/testsuite/ChangeLog:

	* gdb.python/py-framefilter-gdb.py.in: Rename to:
	* gdb.python/py-framefilter-gdb.py: ... this.
	* gdb.python/py-framefilter-invalidarg-gdb.py.in: Rename to:
	* gdb.python/py-framefilter-invalidarg-gdb.py: ... this.

Change-Id: I63bb94010bbbc33434ee1c91a386c91fc1ff80bc

When running black to format Python files, files with extension .py.in
are ignored, because they don't end in .py.  Add a pyproject.toml file
to instruct black to pick up these files too.

gdb/ChangeLog:

	* py-project.toml: New.
	* gdb-gdb.py.in: Re-format.

gdb/testsuite/ChangeLog:

	* gdb.python/py-framefilter-gdb.py.in: Re-format.
	* gdb.python/py-framefilter-invalidarg-gdb.py.in: Re-format.

Change-Id: I9b88faec3360ea24788f44c8b89fe0b2a5f4eb97

Same idea as the previous patches, but for whether a command is a
"command class help" command.  I think this one is particularly useful,
because it's not obvious when reading code what "c->func == NULL" means.

Remove the cmd_func_p function, which does kind of the same thing as
cmd_list_element::is_command_class_help (except it doesn't give a clue
about the semantic of a NULL func value).

gdb/ChangeLog:

	* cli/cli-decode.h (cmd_list_element) <is_command_class_help>:
	New, use it.
	* command.h (cmd_func_p): Remove.
	* cli/cli-decode.c (cmd_func_p): Remove.

Change-Id: I521a3e1896dc93a5babe1493d18f5eb071e1b3b7

Same idea as the previous patch, but for prefix instead of alias.

gdb/ChangeLog:

	* cli/cli-decode.h (cmd_list_element) <is_prefix>: New, use it.

Change-Id: I76a9d2e82fc8d7429904424674d99ce6f9880e2b

Add the cmd_list_element::is_alias helper to check whether a command is
an alias.  I find it easier to understand the intention in:

  if (c->is_alias ())

than

  if (c->alias_target != nullptr)

Change all the spots that are reading alias_target just to compare it to
NULL/nullptr to use is_alias instead.

gdb/ChangeLog:

	* cli/cli-decode.h (cmd_list_element) <is_alias>: New, use it.

Change-Id: I26ed56f99ee47fe884fdfedf87016501631693ce

cmd_pointer is another field whose name I found really not clear.  Yes,
it's a pointer to a command, the type tells me that.  But what's the
relationship of that command to the current command?  This field
contains, for an alias, the command that it aliases.  So I think that
the name "alias_target" would be more appropriate.

Also, rename "old" parameters to "target" in the functions that add
aliases.

gdb/ChangeLog:

	* cli/cli-decode.h (cmd_list_element) <cmd_pointer>: Rename
	to...
	<alias_target>: ... this.
	(add_alias_cmd): Rename old to target.
	(add_info_alias): Rename old_name to target_name.
	(add_com_alias): Likewise.

Change-Id: I8db36c6dd799fae155f7acd3805f6d62d98befa9

While browsing this code, I found the name "prefixlist" really
confusing.  I kept reading it as "list of prefixes".  Which it isn't:
it's a list of sub-commands, for a prefix command.  I think that
renaming it to "subcommands" would make things clearer.

gdb/ChangeLog:

	* Rename "prefixlist" parameters to "subcommands" throughout.
	* cli/cli-decode.h (cmd_list_element) <prefixlist>: Rename to...
	<subcommands>: ... this.
	* cli/cli-decode.c (lookup_cmd_for_prefixlist): Rename to...
	(lookup_cmd_with_subcommands): ... this.

Change-Id: I150da10d03052c2420aa5b0dee41f422e2a97928

I don't think this can ever happen, that we add an alias command and
pass a nullptr old (target) command.  Remove the "if" handling this,
replace with an assert.

gdb/ChangeLog:

	* cli/cli-decode.c (add_alias_cmd): Don't handle old == 0.

Change-Id: Ibb39e8dc4e0c465fa42e6826215f30a0a0aef932

I don't think this method really benefits from being implemented in the
header file, especially because it's recursive, it can't be inlined.
Move it to the source file, so it's no re-compiled by every CU
including cli/cli-decode.h.

I also noticed this method could be const, make it so.

gdb/ChangeLog:

	* cli/cli-decode.h (prefixname): Make const, move implementation
	to cli/cli-decode.c.
	* cli/cli-decode.c (cmd_list_element::prefixname): New.

Change-Id: I1597cace98d9a4ba71f51f1f495e73cc07b5dcf3

The initial problem I wanted to fix here is that GAS was rejecting MVE
instructions such as:

vmov q3[2], q3[0], r2, r2

with:

Error: General purpose registers may not be the same -- `vmov q3[2],q3[0],r2,r2'

which is incorrect; such instructions are valid. Note that for moves in
the other direction, e.g.:

vmov r2, r2, q3[2], q3[0]

GAS is correct in rejecting this as it does not make sense to move both
lanes into the same register (the Arm ARM says this is CONSTRAINED
UNPREDICTABLE).

After fixing this issue, I added assembly/disassembly tests for these
vmovs. This revealed several disassembly issues, including incorrectly
marking the moves into vector lanes as UNPREDICTABLE, and disassembling
many of the vmovs as vector loads. These are now fixed.

gas/ChangeLog:

	* config/tc-arm.c (do_mve_mov): Only reject vmov if we're moving
	into the same GPR twice.
	* testsuite/gas/arm/mve-vmov-bad-2.l: Tweak error message.
	* testsuite/gas/arm/mve-vmov-3.d: New test.
	* testsuite/gas/arm/mve-vmov-3.s: New test.

opcodes/ChangeLog:

	* arm-dis.c (mve_opcodes): Fix disassembly of
	MVE_VMOV2_GP_TO_VEC_LANE when idx == 1.
	(is_mve_encoding_conflict): MVE vector loads should not match
	when P = W = 0.
	(is_mve_unpredictable): It's not unpredictable to use the same
	source register twice (for MVE_VMOV2_GP_TO_VEC_LANE).

As mentioned in the test case itself, depending on the fortran compiler
used, class member names used in the print commands and also output of
these print commands varies. Existing print commands and its output are
suited for gfortran, hence they were failing with clang compiler and test
case was modified accordingly for clang compiler.

gdb/testsuite/ChangeLog:
        * gdb.base/class-allocatable-array.exp: Modified test for clang.

Now that all ports have migrated to the new framework, drop support
for the old sim_state_base layout.

Currently all ports have to declare sim_state themselves in their
sim-main.h and then embed the common sim_state_base & sim_cpu in it.
This dynamic makes it impossible to share common object code among
multiple ports because the core data structure is always different.

Let's invert this relationship: common code declares sim_state, and
if the port actually needs state on a per-instance basis, it can use
the new arch_data field for it.  Most ports don't actually use it,
so they don't need to declare anything at all.

This is the first in a series of changes: it adds a define to select
between the old & new layouts, then converts all the ports that don't
need custom state over to the new layout.

We install libsim.a for people to link against, but haven't been
installing the header files to for its API.  Export them!

The defs.h header will take care of including the various config.h
headers.  For now, it's just config.h, but we'll add more when we
integrate gnulib in.

This header should be used instead of config.h, and should be the
first include in every .c file.  We won't rely on the old behavior
where we expected files to include the port's sim-main.h which then
includes the common sim-basics.h which then includes config.h.  We
have a ton of code that includes things before sim-main.h, and it
sometimes needs to be that way.  Creating a dedicated header avoids
the ordering mess and implicit inclusion that shows up otherwise.

The problems can be illustrated, with any program, below:

(gdb) print main
$1 = {main} 0x0

The return type was incorrectly set in read_func_kind_type, with
the name of the function, which leads c_type_print_base_1 to print
it. In addition, the address of a new function needs to be set with
that info in its minimal symtab entry, when the new function is added.

After the fix:

(gdb) print main
$1 = {int ()} 0x4004b7 <main>

A new test, gdb.ctf/funcreturn.exp, is added to the testsuite.

gdb/ChangeLog:
        * ctfread.c (new_symbol): Set function address.
        (read_func_kind_type): Remove incorrect type name setting.
        Don't copy name returned from ctf_type_ame_raw throughout file.

gdb/testsuite/ChangeLog:
        * gdb.ctf/funcreturn.exp: New file.
        * gdb.ctf/whatis.c: Copy from gdb.base.

A random grab bag of minor fixes to enable -Werror for this port.

Cast address vars to long when the format was using %l.
Use %zu with sizeof operations.
Add const to a bunch of strings.
Trim unused variables.
Fix sizeof call to calculate target storage and not the pointer itself.

Drop our compat code and assume environ exists to simplify.

	* dwarf.c (process_cu_tu_index): Avoid pointer UB.  Use _mul_overflow.
	Delete dead code.

	* dwarf.c (display_gdb_index): Avoid pointer UB and overflow in
	length calculations.

	* dwarf.c (display_debug_names): Complain when header length is
	too small.  Avoid pointer UB.  Sanity check augmentation string,
	CU table, TU table and foreign TU table sizes.

	* dwarf.c (display_debug_frames): Delete initial_length_size.
	Avoid pointer UB.  Constrain data reads to length given in header.
	Sanity check cie header length.  Only skip up to next FDE on
	finding augmentation data too long.

	* dwarf.c (read_cie): Add more sanity checks to ensure data
	pointer is not bumped past end.

	* dwarf.c (display_debug_ranges): Delete initial_length_size.
	Correct fallback size calculated on finding a reloc.  Constrain
	data reads to length given in header.  Avoid pointer UB.