#include "cp-abi.h"
#include "cp-support.h"
#include "demangle.h"
+#include "dwarf2.h"
#include "objfiles.h"
#include "valprint.h"
#include "c-lang.h"
return real_stop_pc;
}
+/* A member function is in one these states. */
+
+enum definition_style
+{
+ DOES_NOT_EXIST_IN_SOURCE,
+ DEFAULTED_INSIDE,
+ DEFAULTED_OUTSIDE,
+ DELETED,
+ EXPLICIT,
+};
+
+/* Return how the given field is defined. */
+
+static definition_style
+get_def_style (struct fn_field *fn, int fieldelem)
+{
+ if (TYPE_FN_FIELD_DELETED (fn, fieldelem))
+ return DELETED;
+
+ if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem))
+ return DOES_NOT_EXIST_IN_SOURCE;
+
+ switch (TYPE_FN_FIELD_DEFAULTED (fn, fieldelem))
+ {
+ case DW_DEFAULTED_no:
+ return EXPLICIT;
+ case DW_DEFAULTED_in_class:
+ return DEFAULTED_INSIDE;
+ case DW_DEFAULTED_out_of_class:
+ return DEFAULTED_OUTSIDE;
+ default:
+ break;
+ }
+
+ return EXPLICIT;
+}
+
+/* Helper functions to determine whether the given definition style
+ denotes that the definition is user-provided or implicit.
+ Being defaulted outside the class decl counts as an explicit
+ user-definition, while being defaulted inside is implicit. */
+
+static bool
+is_user_provided_def (definition_style def)
+{
+ return def == EXPLICIT || def == DEFAULTED_OUTSIDE;
+}
+
+static bool
+is_implicit_def (definition_style def)
+{
+ return def == DOES_NOT_EXIST_IN_SOURCE || def == DEFAULTED_INSIDE;
+}
+
+/* Helper function to decide if METHOD_TYPE is a copy/move
+ constructor type for CLASS_TYPE. EXPECTED is the expected
+ type code for the "right-hand-side" argument.
+ This function is supposed to be used by the IS_COPY_CONSTRUCTOR_TYPE
+ and IS_MOVE_CONSTRUCTOR_TYPE functions below. Normally, you should
+ not need to call this directly. */
+
+static bool
+is_copy_or_move_constructor_type (struct type *class_type,
+ struct type *method_type,
+ type_code expected)
+{
+ /* The method should take at least two arguments... */
+ if (TYPE_NFIELDS (method_type) < 2)
+ return false;
+
+ /* ...and the second argument should be the same as the class
+ type, with the expected type code... */
+ struct type *arg_type = TYPE_FIELD_TYPE (method_type, 1);
+
+ if (TYPE_CODE (arg_type) != expected)
+ return false;
+
+ struct type *target = check_typedef (TYPE_TARGET_TYPE (arg_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 aktemur/2019-10-31: 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.
+ GCC bug link:
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42959
+ */
+ return false;
+ }
+
+ return true;
+}
+
+/* Return true if METHOD_TYPE is a copy ctor type for CLASS_TYPE. */
+
+static bool
+is_copy_constructor_type (struct type *class_type,
+ struct type *method_type)
+{
+ return is_copy_or_move_constructor_type (class_type, method_type,
+ TYPE_CODE_REF);
+}
+
+/* Return true if METHOD_TYPE is a move ctor type for CLASS_TYPE. */
+
+static bool
+is_move_constructor_type (struct type *class_type,
+ struct type *method_type)
+{
+ return is_copy_or_move_constructor_type (class_type, method_type,
+ TYPE_CODE_RVALUE_REF);
+}
+
/* Return pass-by-reference information for the given TYPE.
The rule in the v3 ABI document comes from section 3.1.1. If the
is one or perform the copy itself otherwise), pass the address of
the copy, and then destroy the temporary (if necessary).
- For return values with non-trivial copy constructors or
+ For return values with non-trivial copy/move constructors or
destructors, space will be allocated in the caller, and a pointer
will be passed as the first argument (preceding "this").
We don't have a bulletproof mechanism for determining whether a
- constructor or destructor is trivial. For GCC and DWARF2 debug
- information, we can check the artificial flag.
-
- We don't do anything with the constructors or destructors,
- but we have to get the argument passing right anyway. */
+ constructor or destructor is trivial. For GCC and DWARF5 debug
+ information, we can check the calling_convention attribute,
+ the 'artificial' flag, the 'defaulted' attribute, and the
+ 'deleted' attribute. */
static struct language_pass_by_ref_info
gnuv3_pass_by_reference (struct type *type)
struct language_pass_by_ref_info info
= default_pass_by_reference (type);
- /* FIXME: Currently, this implementation only fills in the
- 'trivially-copyable' field to preserve GDB's existing behavior. */
+ bool has_cc_attr = false;
+ bool is_pass_by_value = false;
+ bool is_dynamic = false;
+ definition_style cctor_def = DOES_NOT_EXIST_IN_SOURCE;
+ definition_style dtor_def = DOES_NOT_EXIST_IN_SOURCE;
+ definition_style mctor_def = DOES_NOT_EXIST_IN_SOURCE;
/* We're only interested in things that can have methods. */
if (TYPE_CODE (type) != TYPE_CODE_STRUCT
&& TYPE_CODE (type) != TYPE_CODE_UNION)
return info;
+ /* The compiler may have emitted the calling convention attribute.
+ Note: GCC does not produce this attribute as of version 9.2.1.
+ Bug link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92418 */
+ if (TYPE_CPLUS_CALLING_CONVENTION (type) == DW_CC_pass_by_value)
+ {
+ has_cc_attr = true;
+ is_pass_by_value = true;
+ /* Do not return immediately. We have to find out if this type
+ is copy_constructible and destructible. */
+ }
+
+ if (TYPE_CPLUS_CALLING_CONVENTION (type) == DW_CC_pass_by_reference)
+ {
+ has_cc_attr = true;
+ is_pass_by_value = false;
+ }
+
/* A dynamic class has a non-trivial copy constructor.
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;
for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);
const char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum);
struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem);
- /* If this function is marked as artificial, it is compiler-generated,
- and we assume it is trivial. */
- if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem))
- continue;
-
- /* If we've found a destructor, we must pass this by reference. */
if (name[0] == '~')
{
- info.trivially_copyable = false;
- return info;
+ /* We've found a destructor.
+ There should be at most one dtor definition. */
+ gdb_assert (dtor_def == DOES_NOT_EXIST_IN_SOURCE);
+ dtor_def = get_def_style (fn, fieldelem);
}
-
- /* If the mangled name of this method doesn't indicate that it
- is a constructor, we're not interested.
-
- FIXME drow/2007-09-23: We could do this using the name of
- the method and the name of the class instead of dealing
- with the mangled name. We don't have a convenient function
- to strip off both leading scope qualifiers and trailing
- template arguments yet. */
- if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))
- && !TYPE_FN_FIELD_CONSTRUCTOR (fn, fieldelem))
- continue;
-
- /* If this method takes two arguments, and the second argument is
- a reference to this class, then it is a copy constructor. */
- if (TYPE_NFIELDS (fieldtype) == 2)
+ else if (is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))
+ || TYPE_FN_FIELD_CONSTRUCTOR (fn, fieldelem))
{
- struct type *arg_type = TYPE_FIELD_TYPE (fieldtype, 1);
-
- if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
+ /* FIXME drow/2007-09-23: We could do this using the name of
+ the method and the name of the class instead of dealing
+ with the mangled name. We don't have a convenient function
+ to strip off both leading scope qualifiers and trailing
+ template arguments yet. */
+ if (is_copy_constructor_type (type, fieldtype))
+ {
+ /* There may be more than one cctors. E.g.: one that
+ take a const parameter and another that takes a
+ non-const parameter. Such as:
+
+ class K {
+ K (const K &k)...
+ K (K &k)...
+ };
+
+ It is sufficient for the type to be non-trivial
+ even only one of the cctors is explicit.
+ Therefore, update the cctor_def value in the
+ implicit -> explicit direction, not backwards. */
+
+ if (is_implicit_def (cctor_def))
+ cctor_def = get_def_style (fn, fieldelem);
+ }
+ else if (is_move_constructor_type (type, fieldtype))
{
- struct type *arg_target_type
- = check_typedef (TYPE_TARGET_TYPE (arg_type));
- if (class_types_same_p (arg_target_type, type))
- {
- info.trivially_copyable = false;
- return info;
- }
+ /* Again, there may be multiple move ctors. Update the
+ mctor_def value if we found an explicit def and the
+ existing one is not explicit. Otherwise retain the
+ existing value. */
+ if (is_implicit_def (mctor_def))
+ mctor_def = get_def_style (fn, fieldelem);
}
}
}
+ bool cctor_implicitly_deleted
+ = (mctor_def != DOES_NOT_EXIST_IN_SOURCE
+ && cctor_def == DOES_NOT_EXIST_IN_SOURCE);
+
+ bool cctor_explicitly_deleted = (cctor_def == DELETED);
+
+ if (cctor_implicitly_deleted || cctor_explicitly_deleted)
+ info.copy_constructible = false;
+
+ if (dtor_def == DELETED)
+ info.destructible = false;
+
+ info.trivially_destructible = is_implicit_def (dtor_def);
+
+ info.trivially_copy_constructible
+ = (is_implicit_def (cctor_def)
+ && !is_dynamic);
+
+ info.trivially_copyable
+ = (info.trivially_copy_constructible
+ && info.trivially_destructible
+ && !is_user_provided_def (mctor_def));
+
/* Even if all the constructors and destructors were artificial, one
of them may have invoked a non-artificial constructor or
destructor in a base class. If any base class needs to be passed
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 = check_typedef (TYPE_TARGET_TYPE (field_type));
+
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;
if (!field_info.trivially_copyable)
- {
- info.trivially_copyable = false;
- return info;
- }
+ info.trivially_copyable = false;
+ if (!field_info.trivially_copy_constructible)
+ info.trivially_copy_constructible = false;
+ if (!field_info.trivially_destructible)
+ info.trivially_destructible = false;
}
+ /* Consistency check. */
+ if (has_cc_attr && info.trivially_copyable != is_pass_by_value)
+ {
+ /* DWARF CC attribute is not the same as the inferred value;
+ use the DWARF attribute. */
+ info.trivially_copyable = is_pass_by_value;
+ }
+
return info;
}
projects / binutils-gdb.git / commitdiff