gdb: recognize new DWARF attributes: defaulted, deleted, calling conv.

Extend GDB's internal representation of types to include the
DW_AT_calling_convention, DW_AT_defaulted, and DW_AT_deleted attributes
that were introduced in DWARF5.

These attributes will be helpful in a future patch about infcall'ing
functions with call-by-value parameters.  GDB will use the attributes
to decide whether the type of a call-by-value parameter is implicitly
pass-by-reference.

gdb/ChangeLog:
2019-12-20  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* dwarf2read.c (dwarf2_add_member_fn): Read the DW_AT_defaulted
	and DW_AT_deleted attributes of a function.
	(read_structure_type): Read the DW_AT_calling_convention attribute
	of a type.
	(is_valid_DW_AT_defaulted): New function.
	(is_valid_DW_AT_calling_convention_for_type): New function.
	* gdbtypes.h: Include dwarf2.h.
	(struct fn_field)<defaulted>: New field to store the
	DW_AT_defaulted attribute.
	(struct fn_field)<is_deleted>: New field to store the
	DW_AT_deleted attribute.
	(struct cplus_struct_type)<calling_convention>: New field to store
	the DW_AT_calling_convention attribute.
	(TYPE_FN_FIELD_DEFAULTED): New macro.
	(TYPE_FN_FIELD_DELETED): New macro.
	(TYPE_CPLUS_CALLING_CONVENTION): New macro.
	* gdbtypes.c (dump_fn_fieldlists): Update for the changes made
	to the .h file.
	(print_cplus_stuff): Likewise.

Change-Id: I54192f363115b78ec7435a8563b73fcace420765

1 files changed, 61 insertions, 0 deletions

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index ecfae68..6492889 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -15472,6 +15472,25 @@ dwarf2_is_constructor (struct die_info *die, struct dwarf2_cu *cu)
 	  && (type_name[len] == '\0' || type_name[len] == '<'));
 }
 
+/* Check if the given VALUE is a recognized enum
+   dwarf_defaulted_attribute constant according to DWARF5 spec,
+   Table 7.24.  */
+
+static bool
+is_valid_DW_AT_defaulted (ULONGEST value)
+{
+  switch (value)
+    {
+    case DW_DEFAULTED_no:
+    case DW_DEFAULTED_in_class:
+    case DW_DEFAULTED_out_of_class:
+      return true;
+    }
+
+  complaint (_("unrecognized DW_AT_defaulted value (%lu)"), value);
+  return false;
+}
+
 /* Add a member function to the proper fieldlist.  */
 
 static void
@@ -15584,6 +15603,16 @@ dwarf2_add_member_fn (struct field_info *fip, struct die_info *die,
   if (attr && DW_UNSND (attr) != 0)
     fnp->is_artificial = 1;
 
+  /* Check for defaulted methods.  */
+  attr = dwarf2_attr (die, DW_AT_defaulted, cu);
+  if (attr != nullptr && is_valid_DW_AT_defaulted (DW_UNSND (attr)))
+    fnp->defaulted = (enum dwarf_defaulted_attribute) DW_UNSND (attr);
+
+  /* Check for deleted methods.  */
+  attr = dwarf2_attr (die, DW_AT_deleted, cu);
+  if (attr != nullptr && DW_UNSND (attr) != 0)
+    fnp->is_deleted = 1;
+
   fnp->is_constructor = dwarf2_is_constructor (die, cu);
 
   /* Get index in virtual function table if it is a virtual member
@@ -15823,6 +15852,26 @@ maybe_set_alignment (struct dwarf2_cu *cu, struct die_info *die,
 	       objfile_name (cu->per_cu->dwarf2_per_objfile->objfile));
 }
 
+/* Check if the given VALUE is a valid enum dwarf_calling_convention
+   constant for a type, according to DWARF5 spec, Table 5.5.  */
+
+static bool
+is_valid_DW_AT_calling_convention_for_type (ULONGEST value)
+{
+  switch (value)
+    {
+    case DW_CC_normal:
+    case DW_CC_pass_by_reference:
+    case DW_CC_pass_by_value:
+      return true;
+
+    default:
+      complaint (_("unrecognized DW_AT_calling_convention value "
+		   "(%lu) for a type"), value);
+      return false;
+    }
+}
+
 /* Called when we find the DIE that starts a structure or union scope
    (definition) to create a type for the structure or union.  Fill in
    the type's name and general properties; the members will not be
@@ -15904,6 +15953,18 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
   if (cu->language == language_cplus && die->tag == DW_TAG_class_type)
     TYPE_DECLARED_CLASS (type) = 1;
 
+  /* Store the calling convention in the type if it's available in
+     the die.  Otherwise the calling convention remains set to
+     the default value DW_CC_normal.  */
+  attr = dwarf2_attr (die, DW_AT_calling_convention, cu);
+  if (attr != nullptr
+      && is_valid_DW_AT_calling_convention_for_type (DW_UNSND (attr)))
+    {
+      ALLOCATE_CPLUS_STRUCT_TYPE (type);
+      TYPE_CPLUS_CALLING_CONVENTION (type)
+	= (enum dwarf_calling_convention) (DW_UNSND (attr));
+    }
+
   attr = dwarf2_attr (die, DW_AT_byte_size, cu);
   if (attr != nullptr)
     {