RFA: fix crash in expression evaluation

[Tom Tromey <tromey at redhat dot com>]

On irc, Vladimir pointed out this crash:

http://dev.eclipse.org/mhonarc/lists/cdt-dev/msg13422.html

This problem seems to have snuck in via the recent pointer math
changes.

This patch fixes the crash by changing coerce_array to look through
typedefs.

Built and regtested on x86-64 (compile farm).
New test case included.

Please review.

Tom

:ADDPATCH expressions:

2008-10-02  Tom Tromey  <tromey@redhat.com>

	* value.c (coerce_array): Use check_typedef.

2008-10-02  Tom Tromey  <tromey@redhat.com>

	* gdb.base/pointers.exp: Add test.
	* gdb.base/pointers.c (k, S): New typedefs.
	(instance): New global.

diff --git a/gdb/testsuite/gdb.base/pointers.c b/gdb/testsuite/gdb.base/pointers.c
index 85bfdc9..4ee5e78 100644
--- a/gdb/testsuite/gdb.base/pointers.c
+++ b/gdb/testsuite/gdb.base/pointers.c
@@ -71,6 +71,15 @@ float ** ptr_to_ptr_to_float;
 
 int y;
 
+
+typedef long k[5];
+
+typedef struct {
+  k array_variable;
+} S;
+
+S instance;
+
 /* Do nothing function used for forcing some of the above variables to
    be referenced by the program source.  If the variables are not
    referenced, some linkers will remove the symbol from the symbol
diff --git a/gdb/testsuite/gdb.base/pointers.exp b/gdb/testsuite/gdb.base/pointers.exp
index 5532140..d7d17e7 100644
--- a/gdb/testsuite/gdb.base/pointers.exp
+++ b/gdb/testsuite/gdb.base/pointers.exp
@@ -596,3 +596,7 @@ gdb_expect {
     timeout             { fail "(timeout) ptype ppppppC" }
 }
 
+# Regression test for a crash.
+
+gdb_test "p instance.array_variable + 0" \
+  " = \\(long int \\*\\) 0x\[0-9a-f\]*"
diff --git a/gdb/value.c b/gdb/value.c
index f3f2c72..0c33959 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -1692,11 +1692,16 @@ coerce_ref (struct value *arg)
 struct value *
 coerce_array (struct value *arg)
 {
+  struct type *type;
   arg = coerce_ref (arg);
+  type = check_typedef (value_type (arg));
   if (current_language->c_style_arrays
-      && TYPE_CODE (value_type (arg)) == TYPE_CODE_ARRAY)
-    arg = value_coerce_array (arg);
-  if (TYPE_CODE (value_type (arg)) == TYPE_CODE_FUNC)
+      && TYPE_CODE (type) == TYPE_CODE_ARRAY)
+    {
+      arg = value_coerce_array (arg);
+      type = check_typedef (value_type (arg));
+    }
+  if (TYPE_CODE (type) == TYPE_CODE_FUNC)
     arg = value_coerce_function (arg);
   return arg;
 }