* valops.c (value_cast_structs): Return NULL for failure.

	(value_cast): Handle NULL from value_cast_structs.
	(value_fetch_lazy): Call check_typedef.  Remove unused variable.

	testsuite/
	* gdb.base/structs3.c, gdb.base/structs3.exp: New files.

5 files changed, 100 insertions, 5 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c679592..8edf7dd 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2008-09-08  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* valops.c (value_cast_structs): Return NULL for failure.
+	(value_cast): Handle NULL from value_cast_structs.
+	(value_fetch_lazy): Call check_typedef.  Remove unused variable.
+
 2008-09-08  Pedro Alves  <pedro@codesourcery.com>
 
 	* inferior.h (context_switch_to): Delete.
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 4044b60..59b26a4 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2008-09-08  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* gdb.base/structs3.c, gdb.base/structs3.exp: New files.
+
 2008-09-08  Jerome Guitton  <guitton@adacore.com>
 
 	* gdb.arch/powerpc-aix-prologue.c (stack_check_probe_1)
diff --git a/gdb/testsuite/gdb.base/structs3.c b/gdb/testsuite/gdb.base/structs3.c
new file mode 100644
index 0000000..0c20fd7
--- /dev/null
+++ b/gdb/testsuite/gdb.base/structs3.c
@@ -0,0 +1,42 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2008
+   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/>.  */
+
+struct One
+{
+  int x;
+};
+
+struct Two
+{
+  struct One one;
+  int x, y;
+};
+
+struct Two two = { { 1 }, 2, 3 };
+
+typedef struct One tOne;
+typedef struct Two tTwo;
+
+tOne *onep = &two.one;
+tTwo *twop = &two;
+
+int main()
+{
+  onep->x = twop->y;
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/structs3.exp b/gdb/testsuite/gdb.base/structs3.exp
new file mode 100644
index 0000000..bec93b6
--- /dev/null
+++ b/gdb/testsuite/gdb.base/structs3.exp
@@ -0,0 +1,37 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2008 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/>.
+
+set testfile "structs3"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+if { [prepare_for_testing structs3.exp "structs3" "" {debug}] } {
+    return -1
+}
+
+set vhn "\\$\[0-9\]+"
+
+# Check the real contents.
+gdb_test "print two" "$vhn = {one = {x = 1}, x = 2, y = 3}"
+
+# Check through the pointer.
+gdb_test "print *twop" "$vhn = {one = {x = 1}, x = 2, y = 3}"
+
+# Check through a pointer to a smaller type, casted up.
+gdb_test "print *(struct Two *)onep" "$vhn = {one = {x = 1}, x = 2, y = 3}"
+
+gdb_test "print *(tTwo *)onep" "$vhn = {one = {x = 1}, x = 2, y = 3}"
diff --git a/gdb/valops.c b/gdb/valops.c
index 4910649..0d1ffdf 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -193,7 +193,8 @@ allocate_space_in_inferior (int len)
 
 /* Cast struct value VAL to type TYPE and return as a value.
    Both type and val must be of TYPE_CODE_STRUCT or TYPE_CODE_UNION
-   for this to work. Typedef to one of the codes is permitted.  */
+   for this to work.  Typedef to one of the codes is permitted.
+   Returns NULL if the cast is neither an upcast nor a downcast.  */
 
 static struct value *
 value_cast_structs (struct type *type, struct value *v2)
@@ -244,7 +245,8 @@ value_cast_structs (struct type *type, struct value *v2)
 	  return value_at (type, addr2);
 	}
     }
-  return v2;
+
+  return NULL;
 }
 
 /* Cast one pointer or reference type to another.  Both TYPE and
@@ -397,7 +399,12 @@ value_cast (struct type *type, struct value *arg2)
   if ((code1 == TYPE_CODE_STRUCT || code1 == TYPE_CODE_UNION)
       && (code2 == TYPE_CODE_STRUCT || code2 == TYPE_CODE_UNION)
       && TYPE_NAME (type) != 0)
-    return value_cast_structs (type, arg2);
+    {
+      struct value *v = value_cast_structs (type, arg2);
+      if (v)
+	return v;
+    }
+
   if (code1 == TYPE_CODE_FLT && scalar)
     return value_from_double (type, value_as_double (arg2));
   else if (code1 == TYPE_CODE_DECFLOAT && scalar)
@@ -615,9 +622,8 @@ value_fetch_lazy (struct value *val)
   if (VALUE_LVAL (val) == lval_memory)
     {
       CORE_ADDR addr = VALUE_ADDRESS (val) + value_offset (val);
-      int length = TYPE_LENGTH (value_enclosing_type (val));
+      int length = TYPE_LENGTH (check_typedef (value_enclosing_type (val)));
 
-      struct type *type = value_type (val);
       if (length)
 	read_memory (addr, value_contents_all_raw (val), length);
     }