gdb/python: preserve identity for gdb.Symtab objects

This commit changes symtab_to_symtab_object() so that each it is called
with a particular struct symtab * it returns the very same gdb.Symtab
object.

This is done by searching per-objfile linked list of instances and - if
found - return it rather than creating new gdb.Symtab.

Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.python/py-symtab.exp b/gdb/testsuite/gdb.python/py-symtab.exp
index 4765ef5..18d77a0 100644
--- a/gdb/testsuite/gdb.python/py-symtab.exp
+++ b/gdb/testsuite/gdb.python/py-symtab.exp
@@ -90,6 +90,34 @@ gdb_test_multiple "python print (\"simple_struct\" in static_symbols)" \
 	}
     }
 
+# Test symtab identity
+gdb_test "python print (symtab is symtab)"\
+    "True" \
+    "test symtab identity 1"
+gdb_test "python print (symtab is gdb.selected_frame().find_sal().symtab)"\
+    "True" \
+    "test symtab identity 2"
+gdb_test "python print (sal.symtab is gdb.selected_frame().find_sal().symtab)"\
+    "True" \
+    "test symtab identity 3"
+gdb_test "python print (symtab is not \"xxx\")"\
+    "True" \
+    "test symtab non-identity with non-symtab"
+
+# Test symtab equality
+gdb_test "python print (symtab == symtab)"\
+    "True" \
+    "test symtab equality 1"
+gdb_test "python print (symtab == gdb.selected_frame().find_sal().symtab)"\
+    "True" \
+    "test symtab equality 2"
+gdb_test "python print (sal.symtab == gdb.selected_frame().find_sal().symtab)"\
+    "True" \
+    "test symtab equality 3"
+gdb_test "python print (symtab != \"xxx\")"\
+    "True" \
+    "test symtab non-equality with non-symtab"
+
 # Test is_valid when the objfile is unloaded.  This must be the last
 # test as it unloads the object file in GDB.
 gdb_unload