Re: [PATCH] Do not consider reference types as dynamic

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

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Joel suggested in private that if we don't consider reference types as 
dynamic in is_dynamic_type_internal, maybe the corresponding handling of 
reference types in resolve_dynamic_type_internal could be removed too.

I've tried to do this and this still triggers no regression on 
x86_64-linux. It's not surprising actually, since 
resolve_dynamic_type_internal does nothing on a type when 
is_dynamic_type_internal returns false for it.

So here's the updated patch. Thanks Joel for the idea! :-)

-- 
Pierre-Marie de Rodat

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From f3fd1a7e81fad7a0b8e4f483f79b2470a3cf1499 Mon Sep 17 00:00:00 2001
From: Pierre-Marie de Rodat <derodat@adacore.com>
Date: Fri, 3 Apr 2015 10:40:52 +0200
Subject: [PATCH] Do not consider reference types as dynamic

Even when referenced types are dynamic, the corresponding referencing
type should not be considered as dynamic: it's only a pointer.  This
prevents reference type for values not in memory to be resolved.

gdb/ChangeLog:
2015-04-03  Pierre-Marie de Rodat  <derodat@adacore.com>

	* gdbtypes.c (is_dynamic_type_internal): Remove special handling
	of TYPE_CODE_REF types so that they are not considered as
	dynamic depending on the referenced type.
	(resolve_dynamic_type_internal): Likewise.

gdb/testsuite/ChangeLog:
2015-04-03  Pierre-Marie de Rodat  <derodat@adacore.com>

	* gdb.ada/funcall_ref.exp: New file.
	* gdb.ada/funcall_ref/foo.adb: New file.
---
 gdb/gdbtypes.c                            | 19 -------------
 gdb/testsuite/gdb.ada/funcall_ref.exp     | 44 +++++++++++++++++++++++++++++++
 gdb/testsuite/gdb.ada/funcall_ref/foo.adb | 34 ++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 19 deletions(-)
 create mode 100644 gdb/testsuite/gdb.ada/funcall_ref.exp
 create mode 100644 gdb/testsuite/gdb.ada/funcall_ref/foo.adb

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 217ec70..6fb2e9a 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1752,10 +1752,6 @@ is_dynamic_type_internal (struct type *type, int top_level)
 {
   type = check_typedef (type);
 
-  /* We only want to recognize references at the outermost level.  */
-  if (top_level && TYPE_CODE (type) == TYPE_CODE_REF)
-    type = check_typedef (TYPE_TARGET_TYPE (type));
-
   /* Types that have a dynamic TYPE_DATA_LOCATION are considered
      dynamic, even if the type itself is statically defined.
      From a user's point of view, this may appear counter-intuitive;
@@ -2045,21 +2041,6 @@ resolve_dynamic_type_internal (struct type *type,
 
       switch (TYPE_CODE (type))
 	{
-	case TYPE_CODE_REF:
-	  {
-	    struct property_addr_info pinfo;
-
-	    pinfo.type = check_typedef (TYPE_TARGET_TYPE (type));
-	    pinfo.addr = read_memory_typed_address (addr_stack->addr, type);
-	    pinfo.next = addr_stack;
-
-	    resolved_type = copy_type (type);
-	    TYPE_TARGET_TYPE (resolved_type)
-	      = resolve_dynamic_type_internal (TYPE_TARGET_TYPE (type),
-					       &pinfo, top_level);
-	    break;
-	  }
-
 	case TYPE_CODE_ARRAY:
 	  resolved_type = resolve_dynamic_array (type, addr_stack);
 	  break;
diff --git a/gdb/testsuite/gdb.ada/funcall_ref.exp b/gdb/testsuite/gdb.ada/funcall_ref.exp
new file mode 100644
index 0000000..444e9d2
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/funcall_ref.exp
@@ -0,0 +1,44 @@
+# Copyright 2008-2015 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 foo
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable \
+                     [list debug]] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/foo.adb]
+runto "foo.adb:$bp_location"
+
+# Test printing and type-printing of a discriminated record that a function
+# returns by reference.
+
+# Currently, GCC describes such functions as returning pointers (instead of
+# references).
+setup_xfail *-*-*
+gdb_test "p get (\"Hello world!\")" \
+         "= \\(n => 12, s => \"Hello world!\"\\)" \
+
+setup_xfail *-*-*
+gdb_test "ptype get (\"Hello world!\")" \
+         [multi_line "type = <ref> record" \
+                     "    n: natural;" \
+                     "    s: access array \\(1 \\.\\. n\\) of character;" \
+                     "end record"] \
diff --git a/gdb/testsuite/gdb.ada/funcall_ref/foo.adb b/gdb/testsuite/gdb.ada/funcall_ref/foo.adb
new file mode 100644
index 0000000..84655d3
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/funcall_ref/foo.adb
@@ -0,0 +1,34 @@
+--  Copyright 2008-2015 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/>.
+
+procedure Foo is
+   type Bar (N : Natural) is record
+      S : String (1 .. N);
+   end record;
+
+   function Get (S : String) return Bar is
+   begin
+      return (N => S'Length, S => S);
+   end Get;
+
+   procedure Do_Nothing (B : Bar) is
+   begin
+      null;
+   end Do_Nothing;
+
+   B : Bar := Get ("Foo");
+begin
+   Do_Nothing (B); --  STOP
+end Foo;
-- 
2.3.4