[PATCH 1/2] Preserve typedef layer when getting struct element

[Pierre-Marie de Rodat <derodat@adacore.com>]

[-- Attachment #1: Type: text/plain, Size: 1764 bytes --]

On behalf of Joel:

Consider the following declarations:

    type Int_Access is access Integer;
    type Record_Type is record
       IA : Int_Access;
    end record;

    R : Record_Type;

Printing the type name of "R.IA" yields:

     (gdb) whatis r.ia
     type = access integer

It should be:

     (gdb) whatis r.ia
     type = bar.int_access

Looking at the debugging info, field "r.ia" is defined as
a typedef which has the name of the field type:

         .uleb128 0x3    # (DIE (0x4e) DW_TAG_typedef)
         .long   .LASF4  # DW_AT_name: "bar__int_access"
         .long   0x8b    # DW_AT_type

... with the typedef's target type being an anonymous pointer
type:

         .uleb128 0x7    # (DIE (0x8b) DW_TAG_pointer_type)
         .byte   0x8     # DW_AT_byte_size
         .long   0x91    # DW_AT_type

What happens here is that a couple of function in ada-lang.c
always start by stripping all typedef layers when handling
struct fields, with the effect of making us lose the type name
in this case.

We did not understand this at the time the code was written,
but typedefs should be stripped only when we know we do not
need them. So this patch, adjust the code to avoid the stripping
while handling the fields, and adds it back in the lone place
which handles the result of processing and didn't know how to
handle typedefs struct fields yet.

gdb/ChangeLog:

         * ada-lang.c (ada_is_tagged_type): Add call to ada_check_typedef.
         (ada_lookup_struct_elt_type): Remove calls to ada_check_typedef.
         (template_to_static_fixed_type): Call ada_check_typedef only
         when necessary.

gdb/testsuite/ChangeLog:

         * gdb.ada/rec_comp: New testcase.

No regression on x86_64-linux. Ok to push?

-- 
Pierre-Marie de Rodat

[-- Attachment #2: 0001-Ada-Preserve-typedef-layer-when-getting-struct-eleme.patch --]
[-- Type: text/x-diff, Size: 9202 bytes --]

From 567d1e0adbc7179bec6795cbbfa19248058373b2 Mon Sep 17 00:00:00 2001
From: Joel Brobecker <brobecker@adacore.com>
Date: Thu, 12 Feb 2015 14:39:14 +0400
Subject: [PATCH 1/2] [Ada] Preserve typedef layer when getting struct element

Consider the following declarations:

   type Int_Access is access Integer;
   type Record_Type is record
      IA : Int_Access;
   end record;

   R : Record_Type;

Printing the type name of "R.IA" yields:

    (gdb) whatis r.ia
    type = access integer

It should be:

    (gdb) whatis r.ia
    type = bar.int_access

Looking at the debugging info, field "r.ia" is defined as
a typedef which has the name of the field type:

        .uleb128 0x3    # (DIE (0x4e) DW_TAG_typedef)
        .long   .LASF4  # DW_AT_name: "bar__int_access"
        .long   0x8b    # DW_AT_type

... with the typedef's target type being an anonymous pointer
type:

        .uleb128 0x7    # (DIE (0x8b) DW_TAG_pointer_type)
        .byte   0x8     # DW_AT_byte_size
        .long   0x91    # DW_AT_type

What happens here is that a couple of function in ada-lang.c
always start by stripping all typedef layers when handling
struct fields, with the effect of making us lose the type name
in this case.

We did not understand this at the time the code was written,
but typedefs should be stripped only when we know we do not
need them. So this patch, adjust the code to avoid the stripping
while handling the fields, and adds it back in the lone place
which handles the result of processing and didn't know how to
handle typedefs struct fields yet.

gdb/ChangeLog:

        * ada-lang.c (ada_is_tagged_type): Add call to ada_check_typedef.
        (ada_lookup_struct_elt_type): Remove calls to ada_check_typedef.
        (template_to_static_fixed_type): Call ada_check_typedef only
        when necessary.

gdb/testsuite/ChangeLog:

        * gdb.ada/rec_comp: New testcase.
---
 gdb/ada-lang.c                                  | 13 ++++++---
 gdb/testsuite/gdb.ada/rec_comp.exp              | 37 +++++++++++++++++++++++++
 gdb/testsuite/gdb.ada/rec_comp/bar_o203_012.adb | 32 +++++++++++++++++++++
 gdb/testsuite/gdb.ada/rec_comp/pck.adb          | 23 +++++++++++++++
 gdb/testsuite/gdb.ada/rec_comp/pck.ads          | 22 +++++++++++++++
 5 files changed, 123 insertions(+), 4 deletions(-)
 create mode 100644 gdb/testsuite/gdb.ada/rec_comp.exp
 create mode 100644 gdb/testsuite/gdb.ada/rec_comp/bar_o203_012.adb
 create mode 100644 gdb/testsuite/gdb.ada/rec_comp/pck.adb
 create mode 100644 gdb/testsuite/gdb.ada/rec_comp/pck.ads

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 124e370..e147d5a 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -6399,6 +6399,8 @@ ada_is_tagged_type (struct type *type, int refok)
 int
 ada_is_tag_type (struct type *type)
 {
+  type = ada_check_typedef (type);
+
   if (type == NULL || TYPE_CODE (type) != TYPE_CODE_PTR)
     return 0;
   else
@@ -7322,7 +7324,7 @@ ada_lookup_struct_elt_type (struct type *type, char *name, int refok,
         {
           if (dispp != NULL)
             *dispp += TYPE_FIELD_BITPOS (type, i) / 8;
-          return ada_check_typedef (TYPE_FIELD_TYPE (type, i));
+          return TYPE_FIELD_TYPE (type, i);
         }
 
       else if (ada_is_wrapper_field (type, i))
@@ -7354,7 +7356,7 @@ ada_lookup_struct_elt_type (struct type *type, char *name, int refok,
               disp = 0;
 	      if (v_field_name != NULL 
 		  && field_name_match (v_field_name, name))
-		t = ada_check_typedef (TYPE_FIELD_TYPE (field_type, j));
+		t = TYPE_FIELD_TYPE (field_type, j);
 	      else
 		t = ada_lookup_struct_elt_type (TYPE_FIELD_TYPE (field_type,
 								 j),
@@ -8177,11 +8179,14 @@ template_to_static_fixed_type (struct type *type0)
 
   for (f = 0; f < nfields; f += 1)
     {
-      struct type *field_type = ada_check_typedef (TYPE_FIELD_TYPE (type0, f));
+      struct type *field_type = TYPE_FIELD_TYPE (type0, f);
       struct type *new_type;
 
       if (is_dynamic_field (type0, f))
-        new_type = to_static_fixed_type (TYPE_TARGET_TYPE (field_type));
+	{
+	  field_type = ada_check_typedef (field_type);
+          new_type = to_static_fixed_type (TYPE_TARGET_TYPE (field_type));
+	}
       else
         new_type = static_unwrap_type (field_type);
       if (type == type0 && new_type != field_type)
diff --git a/gdb/testsuite/gdb.ada/rec_comp.exp b/gdb/testsuite/gdb.ada/rec_comp.exp
new file mode 100644
index 0000000..c462643
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/rec_comp.exp
@@ -0,0 +1,37 @@
+# Copyright 2015 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 "ada.exp"
+
+standard_ada_testfile bar_o203_012
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/bar_o203_012.adb]
+if ![runto "bar_o203_012.adb:$bp_location" ] then {
+  perror "Couldn't run ${testfile}"
+  return
+}
+
+gdb_test "whatis r.ia" " = bar_o203_012.int_access"
+
+gdb_test "ptype r" \
+    " = record\r\n *ia: bar_o203_012\.int_access;\r\nend record"
+
+gdb_test "ptype r.ia" " = access <$decimal-byte integer>"
diff --git a/gdb/testsuite/gdb.ada/rec_comp/bar_o203_012.adb b/gdb/testsuite/gdb.ada/rec_comp/bar_o203_012.adb
new file mode 100644
index 0000000..9783f51
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/rec_comp/bar_o203_012.adb
@@ -0,0 +1,32 @@
+--  Copyright 2015 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/>.
+
+with Pck; use Pck;
+
+procedure Bar_O203_012 is
+   type Int_Access is access Integer;
+   type Record_Type is record
+      IA : Int_Access;
+   end record;
+
+   R : Record_Type;
+   IA : Int_Access;
+begin
+   R.IA := new Integer'(3); -- STOP
+   IA := R.IA;
+   Do_Nothing (R'Address);
+   Do_Nothing (IA'Address);
+end Bar_O203_012;
+
diff --git a/gdb/testsuite/gdb.ada/rec_comp/pck.adb b/gdb/testsuite/gdb.ada/rec_comp/pck.adb
new file mode 100644
index 0000000..c0465af
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/rec_comp/pck.adb
@@ -0,0 +1,23 @@
+--  Copyright 2011-2015 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/>.
+
+package body Pck is
+
+   procedure Do_Nothing (A : System.Address) is
+   begin
+      null;
+   end Do_Nothing;
+
+end Pck;
diff --git a/gdb/testsuite/gdb.ada/rec_comp/pck.ads b/gdb/testsuite/gdb.ada/rec_comp/pck.ads
new file mode 100644
index 0000000..594847c
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/rec_comp/pck.ads
@@ -0,0 +1,22 @@
+--  Copyright 2011-2015 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/>.
+
+with System;
+
+package Pck is
+
+   procedure Do_Nothing (A : System.Address);
+
+end Pck;
-- 
2.3.4