[review v2] infcall, c++: collect more pass-by-reference information

["Tankut Baris Aktemur (Code Review)" <gerrit@gnutoolchain-gerrit.osci.io>]

Tankut Baris Aktemur has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/137
......................................................................


Patch Set 2:

(3 comments)

| --- gdb/gnu-v3-abi.c
| +++ gdb/gnu-v3-abi.c
| @@ -1233,0 +1312,23 @@ is_copy_or_move_constructor_type (struct type *class_type,
| +  if (!(class_types_same_p (target, class_type)))
| +    return false;
| +
| +  /* ...and if any of the remaining arguments don't have a default value
| +     then this is not a copy or move constructor, but just a
| +     constructor.  */
| +  for (int i = 2; i < TYPE_NFIELDS (method_type); i++)
| +    {
| +      arg_type = TYPE_FIELD_TYPE (method_type, i);
| +      /* FIXME taktemur/2019-04-23: As of this date, neither
| +	 clang++-7.0.0 nor g++-8.2.0 produce a DW_AT_default_value
| +	 attribute.  GDB is also not set to read this attribute, yet.
| +	 Hence, we immediately return false if there are more than
| +	 2 parameters.  */

PS1, Line 1325:

Added: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42959
(The ticket was opened by you :)

| +      return false;
| +    }
| +
| +  return true;
| +}
| +
| +/* Return true if METHOD_TYPE is a copy ctor type for CLASS_TYPE.  */
| +
| +static bool

 ...

| @@ -1272,9 +1409,14 @@ gnuv3_pass_by_reference (struct type *type)
|       See c++98 section 12.8 Copying class objects [class.copy].  */
|    if (gnuv3_dynamic_class (type))
| -    {
| -      info.trivially_copyable = false;
| -      return info;
| -    }
| -
| +    is_dynamic = true;
| +
| +  /* FIXME taktemur/2019-04-23: What if there are multiple copy ctors?

PS1, Line 1413:

Following the recent overload resolution fixes, this now works.  The
`language_pass_by_ref_info` that was defined at

https://gnutoolchain-gerrit.osci.io/r/c/binutils-
gdb/+/136/2/gdb/language.h#146

is also simplified -- no need to carry the copy-ctor and dtor function
names anymore.

The call to overload resolution happens inside infrun.c, as part of
this patch:

https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/141

| +     E.g.:
| +       class C {
| +       public:
| +	 C (C &c) { ... }
| +	 C (const C &c) { ... }
| +       };
| +  */
|    for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
|      for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);

 ...

| @@ -1335,7 +1486,18 @@ gnuv3_pass_by_reference (struct type *type)
|       about recursive loops here, since we are only looking at members
|       of complete class type.  Also ignore any static members.  */
|    for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++)
|      if (!field_is_static (&TYPE_FIELD (type, fieldnum)))
|        {
| +	struct type *field_type = TYPE_FIELD_TYPE (type, fieldnum);
| +
| +	/* For arrays, make the decision based on the element type.  */
| +	if (TYPE_CODE (field_type) == TYPE_CODE_ARRAY)
| +	  field_type = field_type->main_type->target_type;

PS1, Line 1495:

Done

| +
|  	struct language_pass_by_ref_info field_info
| -	  = gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum));
| +	  = gnuv3_pass_by_reference (field_type);
| +
| +	if (!field_info.copy_constructible)
| +	  info.copy_constructible = false;
| +	if (!field_info.destructible)
| +	  info.destructible = false;

-- 
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: Ic05bd98a962d07ec3c1ad041f709687eabda3bb9
Gerrit-Change-Number: 137
Gerrit-PatchSet: 2
Gerrit-Owner: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Gerrit-Reviewer: Andrew Burgess <andrew.burgess@embecosm.com>
Gerrit-Reviewer: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Gerrit-Reviewer: Tom Tromey <tromey@sourceware.org>
Gerrit-Comment-Date: Mon, 09 Dec 2019 17:54:55 +0000
Gerrit-HasComments: Yes
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Comment-In-Reply-To: Tom Tromey <tromey@sourceware.org>
Comment-In-Reply-To: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Gerrit-MessageType: comment