Create dwarf2/attribute.[ch]

This moves the attribute-related code out of dwarf2read.c and into the
new files dwarf2/attribute.[ch].

gdb/ChangeLog
2020-02-08  Tom Tromey  <tom@tromey.com>

	* dwarf2read.c (struct attribute, DW_STRING)
	(DW_STRING_IS_CANONICAL, DW_UNSND, DW_BLOCK, DW_SND, DW_ADDR)
	(DW_SIGNATURE, struct dwarf_block, attr_value_as_address)
	(attr_form_is_block, attr_form_is_section_offset)
	(attr_form_is_constant, attr_form_is_ref): Move.
	* dwarf2/attribute.h: New file.
	* dwarf2/attribute.c: New file, from dwarf2read.c.
	* Makefile.in (COMMON_SFILES): Add dwarf2/attribute.c.

Change-Id: I1ea4c146256a1b9e38b66f1c605d782a14eeded7

1 files changed, 122 insertions, 0 deletions

diff --git a/gdb/dwarf2/attribute.c b/gdb/dwarf2/attribute.c
new file mode 100644
index 0000000..75a2fa3
--- /dev/null
+++ b/gdb/dwarf2/attribute.c
@@ -0,0 +1,122 @@
+/* DWARF attributes
+
+   Copyright (C) 1994-2020 Free Software Foundation, Inc.
+
+   Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
+   Inc.  with support from Florida State University (under contract
+   with the Ada Joint Program Office), and Silicon Graphics, Inc.
+   Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
+   based on Fred Fish's (Cygnus Support) implementation of DWARF 1
+   support.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "dwarf2/attribute.h"
+
+/* See attribute.h.  */
+
+CORE_ADDR
+attr_value_as_address (struct attribute *attr)
+{
+  CORE_ADDR addr;
+
+  if (attr->form != DW_FORM_addr && attr->form != DW_FORM_addrx
+      && attr->form != DW_FORM_GNU_addr_index)
+    {
+      /* Aside from a few clearly defined exceptions, attributes that
+	 contain an address must always be in DW_FORM_addr form.
+	 Unfortunately, some compilers happen to be violating this
+	 requirement by encoding addresses using other forms, such
+	 as DW_FORM_data4 for example.  For those broken compilers,
+	 we try to do our best, without any guarantee of success,
+	 to interpret the address correctly.  It would also be nice
+	 to generate a complaint, but that would require us to maintain
+	 a list of legitimate cases where a non-address form is allowed,
+	 as well as update callers to pass in at least the CU's DWARF
+	 version.  This is more overhead than what we're willing to
+	 expand for a pretty rare case.  */
+      addr = DW_UNSND (attr);
+    }
+  else
+    addr = DW_ADDR (attr);
+
+  return addr;
+}
+
+/* See attribute.h.  */
+
+int
+attr_form_is_block (const struct attribute *attr)
+{
+  return (attr == NULL ? 0 :
+      attr->form == DW_FORM_block1
+      || attr->form == DW_FORM_block2
+      || attr->form == DW_FORM_block4
+      || attr->form == DW_FORM_block
+      || attr->form == DW_FORM_exprloc);
+}
+
+/* See attribute.h.  */
+
+int
+attr_form_is_section_offset (const struct attribute *attr)
+{
+  return (attr->form == DW_FORM_data4
+          || attr->form == DW_FORM_data8
+	  || attr->form == DW_FORM_sec_offset);
+}
+
+/* See attribute.h.  */
+
+int
+attr_form_is_constant (const struct attribute *attr)
+{
+  switch (attr->form)
+    {
+    case DW_FORM_sdata:
+    case DW_FORM_udata:
+    case DW_FORM_data1:
+    case DW_FORM_data2:
+    case DW_FORM_data4:
+    case DW_FORM_data8:
+    case DW_FORM_implicit_const:
+      return 1;
+    default:
+      return 0;
+    }
+}
+
+/* DW_ADDR is always stored already as sect_offset; despite for the forms
+   besides DW_FORM_ref_addr it is stored as cu_offset in the DWARF file.  */
+
+int
+attr_form_is_ref (const struct attribute *attr)
+{
+  switch (attr->form)
+    {
+    case DW_FORM_ref_addr:
+    case DW_FORM_ref1:
+    case DW_FORM_ref2:
+    case DW_FORM_ref4:
+    case DW_FORM_ref8:
+    case DW_FORM_ref_udata:
+    case DW_FORM_GNU_ref_alt:
+      return 1;
+    default:
+      return 0;
+    }
+}