Handle variable-sized fields in the interior of structure type

In Ada, variable-sized field can be located at any position of
a structure. Consider for instance the following declarations:

   Dyn_Size : Integer := 1;

   type Table is array (Positive range <>) of Integer;

   type Inner is record
      T1 : Table (1 .. Dyn_Size) := (others => 1);
      T2 : Table (1 .. Dyn_Size) := (others => 2);
   end record;

   type Inner_Array is array (1 .. 2) of Inner;

   type Outer is
      record
         I0 : Integer := 0;
         A1 : Inner_Array;
         Marker : Integer := 16#01020304#;
      end record;

   Rt : Outer;

What this does is declare a variable "Rt" of type Outer, which
contains 3 fields where the second (A1) is of type Inner_Array.
type Inner_Array is an array with 2 elements of type Inner.
Because type Inner contains two arrays whose upper bound depend
on a variable, the size of the array, and therefore the size of
type Inner is dynamic, thus making field A1 a dynamically-size
field.

When trying to print the value of Rt, we hit the following limitation:

    (gdb) print rt
    Attempt to resolve a variably-sized type which appears in the interior of
    a structure type

The limitation was somewhat making sense in C, but needs to be lifted
for Ada. This patch mostly lifts that limitation. As a result of this
patch, the type length computation had to be reworked a little bit.

gdb/ChangeLog:

        * gdbtypes.c (resolve_dynamic_struct): Do not generate an error
        if detecting a variable-sized field that is not the last field.
        Fix struct type length computation.

gdb/testsuite/ChangeLog:

        * gdb.base/vla-datatypes.c (vla_factory): Add new variable
        inner_vla_struct_object_size.
        * gdb.base/vla-datatypes.exp: Adjust last test, and mark it
        as xfail.

3 files changed, 13 insertions, 3 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 6eb8f3e..eeeab3e 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2014-08-01  Joel Brobecker  <brobecker@adacore.com>
+
+	* gdb.base/vla-datatypes.c (vla_factory): Add new variable
+	inner_vla_struct_object_size.
+	* gdb.base/vla-datatypes.exp: Adjust last test, and mark it
+	as xfail.
+
 2014-07-30  Pedro Alves  <palves@redhat.com>
 
 	* gdb.threads/signal-command-handle-nopass.exp (test): Add
diff --git a/gdb/testsuite/gdb.base/vla-datatypes.c b/gdb/testsuite/gdb.base/vla-datatypes.c
index 1ef30a5..41f3fd3 100644
--- a/gdb/testsuite/gdb.base/vla-datatypes.c
+++ b/gdb/testsuite/gdb.base/vla-datatypes.c
@@ -100,6 +100,7 @@ vla_factory (int n)
   size_t bar_size        = sizeof(bar_vla);
   size_t vla_struct_object_size = sizeof(vla_struct_object);
   size_t vla_union_object_size = sizeof(vla_union_object);
+  size_t inner_vla_struct_object_size = sizeof(inner_vla_struct_object);
 
   return;                                 /* break_end_of_vla_factory */
 }
diff --git a/gdb/testsuite/gdb.base/vla-datatypes.exp b/gdb/testsuite/gdb.base/vla-datatypes.exp
index 0e56bd7..15135a3 100644
--- a/gdb/testsuite/gdb.base/vla-datatypes.exp
+++ b/gdb/testsuite/gdb.base/vla-datatypes.exp
@@ -152,6 +152,8 @@ gdb_test "whatis ++int_vla\[0\]" "type = int" "whatis ++int_vla\[0\]"
 gdb_test "print int_vla\[0\]" " = 42" \
          "print int_vla\[0\] - whatis no side effects"
 
-# This gives an error for now.
-gdb_test "print sizeof(inner_vla_struct_object)" \
-    "appears in the interior of a structure type"
+# Fails due to incorrect debugging information generated by GCC.
+setup_xfail "*-*-*"
+gdb_test \
+    "print inner_vla_struct_object_size == sizeof(inner_vla_struct_object)" \
+    " = 1" "size of inner_vla_struct_object"