[PATCH] GCC5/DWARFv5 Handle DW_TAG_atomic_type for C11 _Atomic type qualifier.

[Mark Wielaard <mjw@redhat.com>]

Hi,

This is a cleanup version of the prototype we discussed 6 months ago.
https://sourceware.org/ml/gdb-patches/2014-06/msg00795.html
GCC now has support for DW_TAG_atomic_type when using the experimental
-gdwarf-5 flag. I fixed up the issues Tom pointed out back in June.
And I changed the testcase to use the DWARF assembler.

gdb/ChangeLog

	* c-typeprint.c (cp_type_print_method_args): Handle '_Atomic'.
	(c_type_print_modifier): Likewise.
	* dwarf2read.c (read_tag_atomic_type): New function.
	(read_type_die_1): Handle DW_TAG_atomic_type.
	* gdbtypes.c (make_atomic_type): New function.
	(recursive_dump_type): Handle TYPE_ATOMIC.
	* gdbtypes.h (enum type_flag_values): Renumber.
	(enum type_instance_flag_value): Add TYPE_INSTANCE_FLAG_ATOMIC.
	(TYPE_ATOMIC): New macro.
	(make_atomic_type): Declare.

gdb/testsuite/ChangeLog

	* gdb.dwarf2/atomic.c: New file.
	* gdb.dwarf2/atomic-type.exp: Likewise.

include/ChangeLog

	* dwarf2.def: Add DW_TAG_atomic_type.

OK to commit?

Thanks,

Mark

---
diff --git a/gdb/c-typeprint.c b/gdb/c-typeprint.c
index 374c90e..ba5b09e 100644
--- a/gdb/c-typeprint.c
+++ b/gdb/c-typeprint.c
@@ -270,6 +270,9 @@ cp_type_print_method_args (struct type *mtype, const char *prefix,
 
       if (TYPE_RESTRICT (domain))
 	fprintf_filtered (stream, " restrict");
+
+      if (TYPE_ATOMIC (domain))
+	fprintf_filtered (stream, " _Atomic");
     }
 }
 
@@ -431,6 +434,14 @@ c_type_print_modifier (struct type *type, struct ui_file *stream,
       did_print_modifier = 1;
     }
 
+  if (TYPE_ATOMIC (type))
+    {
+      if (did_print_modifier || need_pre_space)
+	fprintf_filtered (stream, " ");
+      fprintf_filtered (stream, "_Atomic");
+      did_print_modifier = 1;
+    }
+
   address_space_id = address_space_int_to_name (get_type_arch (type),
 						TYPE_INSTANCE_FLAGS (type));
   if (address_space_id)
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 829611d..3cb8aee 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -14194,6 +14194,24 @@ read_tag_restrict_type (struct die_info *die, struct dwarf2_cu *cu)
   return set_die_type (die, cv_type, cu);
 }
 
+/* Handle DW_TAG_atomic_type.  */
+
+static struct type *
+read_tag_atomic_type (struct die_info *die, struct dwarf2_cu *cu)
+{
+  struct type *base_type, *cv_type;
+
+  base_type = die_type (die, cu);
+
+  /* The die_type call above may have already set the type for this DIE.  */
+  cv_type = get_die_type (die, cu);
+  if (cv_type)
+    return cv_type;
+
+  cv_type = make_atomic_type (base_type);
+  return set_die_type (die, cv_type, cu);
+}
+
 /* Extract all information from a DW_TAG_string_type DIE and add to
    the user defined type vector.  It isn't really a user defined type,
    but it behaves like one, with other DIE's using an AT_user_def_type
@@ -18635,6 +18653,9 @@ read_type_die_1 (struct die_info *die, struct dwarf2_cu *cu)
     case DW_TAG_module:
       this_type = read_module_type (die, cu);
       break;
+    case DW_TAG_atomic_type:
+      this_type = read_tag_atomic_type (die, cu);
+      break;
     default:
       complaint (&symfile_complaints,
 		 _("unexpected tag in read_type_die: '%s'"),
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 611a0e7..a8edc04 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -703,6 +703,17 @@ make_restrict_type (struct type *type)
 			      NULL);
 }
 
+/* Make a '_Atomic'-qualified version of TYPE.  */
+
+struct type *
+make_atomic_type (struct type *type)
+{
+  return make_qualified_type (type,
+			      (TYPE_INSTANCE_FLAGS (type)
+			       | TYPE_INSTANCE_FLAG_ATOMIC),
+			      NULL);
+}
+
 /* Replace the contents of ntype with the type *type.  This changes the
    contents, rather than the pointer for TYPE_MAIN_TYPE (ntype); thus
    the changes are propogated to all types in the TYPE_CHAIN.
@@ -3856,6 +3867,10 @@ recursive_dump_type (struct type *type, int spaces)
     {
       puts_filtered (" TYPE_FLAG_RESTRICT");
     }
+  if (TYPE_ATOMIC (type))
+    {
+      puts_filtered (" TYPE_FLAG_ATOMIC");
+    }
   puts_filtered ("\n");
 
   printfi_filtered (spaces, "flags");
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index a56f543..3001d6a 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -193,18 +193,18 @@ enum type_code
 
 enum type_flag_value
 {
-  TYPE_FLAG_UNSIGNED = (1 << 8),
-  TYPE_FLAG_NOSIGN = (1 << 9),
-  TYPE_FLAG_STUB = (1 << 10),
-  TYPE_FLAG_TARGET_STUB = (1 << 11),
-  TYPE_FLAG_STATIC = (1 << 12),
-  TYPE_FLAG_PROTOTYPED = (1 << 13),
-  TYPE_FLAG_INCOMPLETE = (1 << 14),
-  TYPE_FLAG_VARARGS = (1 << 15),
-  TYPE_FLAG_VECTOR = (1 << 16),
-  TYPE_FLAG_FIXED_INSTANCE = (1 << 17),
-  TYPE_FLAG_STUB_SUPPORTED = (1 << 18),
-  TYPE_FLAG_GNU_IFUNC = (1 << 19),
+  TYPE_FLAG_UNSIGNED = (1 << 9),
+  TYPE_FLAG_NOSIGN = (1 << 10),
+  TYPE_FLAG_STUB = (1 << 11),
+  TYPE_FLAG_TARGET_STUB = (1 << 12),
+  TYPE_FLAG_STATIC = (1 << 13),
+  TYPE_FLAG_PROTOTYPED = (1 << 14),
+  TYPE_FLAG_INCOMPLETE = (1 << 15),
+  TYPE_FLAG_VARARGS = (1 << 16),
+  TYPE_FLAG_VECTOR = (1 << 17),
+  TYPE_FLAG_FIXED_INSTANCE = (1 << 18),
+  TYPE_FLAG_STUB_SUPPORTED = (1 << 19),
+  TYPE_FLAG_GNU_IFUNC = (1 << 20),
 
   /* * Used for error-checking.  */
   TYPE_FLAG_MIN = TYPE_FLAG_UNSIGNED
@@ -223,7 +223,8 @@ enum type_instance_flag_value
   TYPE_INSTANCE_FLAG_ADDRESS_CLASS_1 = (1 << 4),
   TYPE_INSTANCE_FLAG_ADDRESS_CLASS_2 = (1 << 5),
   TYPE_INSTANCE_FLAG_NOTTEXT = (1 << 6),
-  TYPE_INSTANCE_FLAG_RESTRICT = (1 << 7)
+  TYPE_INSTANCE_FLAG_RESTRICT = (1 << 7),
+  TYPE_INSTANCE_FLAG_ATOMIC = (1 << 8)
 };
 
 /* * Unsigned integer type.  If this is not set for a TYPE_CODE_INT,
@@ -355,6 +356,12 @@ enum type_instance_flag_value
 #define TYPE_RESTRICT(t) \
   (TYPE_INSTANCE_FLAGS (t) & TYPE_INSTANCE_FLAG_RESTRICT)
 
+/* * Atomic type.  If this is set, the corresponding type has an
+   _Atomic modifier.  */
+
+#define TYPE_ATOMIC(t) \
+  (TYPE_INSTANCE_FLAGS (t) & TYPE_INSTANCE_FLAG_ATOMIC)
+
 /* * Instruction-space delimited type.  This is for Harvard architectures
    which have separate instruction and data address spaces (and perhaps
    others).
@@ -1632,6 +1639,8 @@ extern struct type *make_cv_type (int, int, struct type *, struct type **);
 
 extern struct type *make_restrict_type (struct type *);
 
+extern struct type *make_atomic_type (struct type *);
+
 extern void replace_type (struct type *, struct type *);
 
 extern int address_space_name_to_int (struct gdbarch *, char *);
diff --git a/gdb/testsuite/gdb.dwarf2/atomic-type.exp b/gdb/testsuite/gdb.dwarf2/atomic-type.exp
new file mode 100644
index 0000000..d7c3bbe
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/atomic-type.exp
@@ -0,0 +1,90 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# 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/>.
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+    return 0
+}
+
+standard_testfile atomic.c atomic-type-dw.S
+
+# Make some DWARF for the test.
+
+set asm_file [standard_output_file $srcfile2]
+#set ptr_size [get_sizeof "void *" 96]
+Dwarf::assemble $asm_file {
+    cu {} {
+	DW_TAG_compile_unit {
+                {DW_AT_language @DW_LANG_C11}
+                {DW_AT_name     atomic-type-dw.c}
+                {DW_AT_comp_dir /tmp}
+        } {
+	    declare_labels i_l c_l c_c_l ac_c_l pac_c_l vpac_c_l avpac_c_l
+
+            i_l: DW_TAG_base_type {
+                {DW_AT_byte_size 4 DW_FORM_sdata}
+                {DW_AT_encoding  @DW_ATE_signed}
+                {DW_AT_name      int}
+            }
+
+            c_l: DW_TAG_base_type {
+                {DW_AT_byte_size 2 DW_FORM_sdata}
+                {DW_AT_encoding  @DW_ATE_unsigned}
+                {DW_AT_name      char}
+            }
+
+            c_c_l: DW_TAG_const_type {
+                {DW_AT_type :$c_l}
+            }
+
+            ac_c_l: DW_TAG_atomic_type {
+                {DW_AT_type :$c_c_l}
+            }
+
+            pac_c_l: DW_TAG_pointer_type {
+                {DW_AT_byte_size 8 DW_FORM_sdata}
+                {DW_AT_type :$ac_c_l}
+            }
+
+            vpac_c_l: DW_TAG_volatile_type {
+                {DW_AT_type :$pac_c_l}
+            }
+
+            avpac_c_l: DW_TAG_atomic_type {
+                {DW_AT_type :$vpac_c_l}
+            }
+
+            DW_TAG_subprogram {
+                {name f}
+                {low_pc f addr}
+                {high_pc f_end_lbl addr}
+                {type :$i_l}
+            } {
+                DW_TAG_formal_parameter {
+                    {type :$avpac_c_l}
+                    {name x}
+                }
+            }
+	}
+    }
+}
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} \
+	  [list $srcfile $asm_file] {nodebug}] } {
+    return -1
+}
+
+gdb_test "ptype f" "int \\(const _Atomic char \\\* volatile _Atomic\\)"
diff --git a/gdb/testsuite/gdb.dwarf2/atomic.c b/gdb/testsuite/gdb.dwarf2/atomic.c
new file mode 100644
index 0000000..6ebb9ca
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/atomic.c
@@ -0,0 +1,34 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004-2014 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* Dummy main function.  */
+
+int
+main()
+{
+  asm ("main_label: .globl main_label");
+  return 0;
+}
+
+/* dummy f function, DWARF will describe arguments and type differently.  */
+int
+f (char *x)
+{
+  asm (".global f_end_lbl\nf_end_lbl:");
+  return 0;
+}
+
diff --git a/include/dwarf2.def b/include/dwarf2.def
index 8ca143c..f75b6f5 100644
--- a/include/dwarf2.def
+++ b/include/dwarf2.def
@@ -133,6 +133,8 @@ DW_TAG (DW_TAG_shared_type, 0x40)
 DW_TAG (DW_TAG_type_unit, 0x41)
 DW_TAG (DW_TAG_rvalue_reference_type, 0x42)
 DW_TAG (DW_TAG_template_alias, 0x43)
+/* DWARF 5.  */
+DW_TAG (DW_TAG_atomic_type, 0x47)
 
 DW_TAG_DUP (DW_TAG_lo_user, 0x4080)
 DW_TAG_DUP (DW_TAG_hi_user, 0xffff)
-- 
1.8.3.1