Avoid expensive complaint calls when complaints are disabled

Running perf on "gdb -nx -readnow -batch gdb", I'm seeing a lot of
time (24%.75!) spent in gettext, via complaints.  'perf report -g' shows:

 -   86.23%     0.00%  gdb      gdb                     [.] gdb_main
    - gdb_main
       - 85.60% catch_command_errors
            symbol_file_add_main_adapter
            symbol_file_add_main
            symbol_file_add_main_1
            symbol_file_add
          - symbol_file_add_with_addrs
             - 84.31% dw2_expand_all_symtabs
                - dw2_instantiate_symtab
                   - 83.79% dw2_do_instantiate_symtab
                      - 70.85% process_die
                         - 41.11% dwarf_decode_macros
                            - 41.09% dwarf_decode_macro_bytes
                               - 39.74% dwarf_decode_macro_bytes
   >>>>>>>>>>>>>>>>>>>>>>>        + 24.75% __dcigettext              <<<<<<<
                                  + 7.37% macro_define_object_internal
                                  + 3.16% macro_define_function
                                    0.77% splay_tree_insert
                                  + 0.76% savestring
                                  + 0.58% free
                                    0.53% read_indirect_string_at_offset_from
                                 0.54% macro_define_object_internal
                                 0.51% macro_start_file
                         + 25.57% process_die
                         + 4.07% dwarf_decode_lines
                      + 4.28% compute_delayed_physnames
                      + 3.85% end_symtab_from_static_block
                      + 3.38% load_cu
                      + 1.29% end_symtab_get_static_block
                   + 0.52% do_my_cleanups
             + 1.29% read_symbols
       + 0.54% gdb_init

The problem is that we're always computing the arguments to pass to
complaint, including passing the format strings through gettext, even
when complaints are disabled.  As seen above, gettext can be quite
expensive.

Fix this by wrapping complaint in a macro that skips the real
complaint call when complaints are disabled.

This improves "gdb -nx -readnow -batch gdb" from
 ~11.0s => ~7.8s with -O2 -g3, and
  ~6.0s => ~5.3s with -O2 -g.
w/ gcc 5.3.1, on x86_64, for me.

gdb/ChangeLog:
2017-11-08  Pedro Alves  <palves@redhat.com>

	* complaints.c (stop_whining): Make extern.
	(complaint): Rename to ...
	(complaint_internal): ... this.
	* complaints.h (complaint): Rename to ...
	(complaint_internal): ... this.
	(complaint): Reimplement as macro around complaint_internal.

gdb/testsuite/ChangeLog:
2017-11-08  Pedro Alves  <palves@redhat.com>

	* gdb.gdb/complaints.exp (test_initial_complaints)
	(test_serial_complaints, test_short_complaints): Call
	complaint_internal instead of complaint.

1 files changed, 17 insertions, 10 deletions

diff --git a/gdb/testsuite/gdb.gdb/complaints.exp b/gdb/testsuite/gdb.gdb/complaints.exp
index c33fb6e..0b03205 100644
--- a/gdb/testsuite/gdb.gdb/complaints.exp
+++ b/gdb/testsuite/gdb.gdb/complaints.exp
@@ -58,16 +58,18 @@ proc test_initial_complaints { } {
     gdb_test "set stop_whining = 2"
 
     # Prime the system
-    gdb_test_stdio "call complaint (&symfile_complaints, \"Register a complaint\")" \
-	    "During symbol reading, Register a complaint."
+    gdb_test_stdio \
+	"call complaint_internal (&symfile_complaints, \"Register a complaint\")" \
+	"During symbol reading, Register a complaint."
 
     # Check that the complaint was inserted and where
     gdb_test "print symfile_complaints->root->fmt" \
 	    ".\[0-9\]+ =.*\"Register a complaint\""
 
     # Re-issue the first message #1
-    gdb_test_stdio "call complaint (&symfile_complaints, symfile_complaints->root->fmt)" \
-	    "During symbol reading, Register a complaint."
+    gdb_test_stdio \
+	"call complaint_internal (&symfile_complaints, symfile_complaints->root->fmt)" \
+	"During symbol reading, Register a complaint."
 
     # Check that there is only one thing in the list.  How the boolean
     # result is output depends on whether GDB is built as a C or C++
@@ -76,8 +78,9 @@ proc test_initial_complaints { } {
 	    ".\[0-9\]+ = \(1|true\)" "list has one entry"
 
     # Add a second complaint, expect it
-    gdb_test_stdio "call complaint (&symfile_complaints, \"Testing! Testing! Testing!\")" \
-	    "During symbol reading, Testing. Testing. Testing.."
+    gdb_test_stdio \
+	"call complaint_internal (&symfile_complaints, \"Testing! Testing! Testing!\")" \
+	"During symbol reading, Testing. Testing. Testing.."
 
     return 0
 }
@@ -86,12 +89,14 @@ proc test_serial_complaints { } {
     gdb_test_exact "call clear_complaints (&symfile_complaints, 1, 0)" "" "serial start"
 
     # Prime the system
-    test_complaint "call complaint (&symfile_complaints, \"serial line 1\")" \
+    test_complaint \
+	"call complaint_internal (&symfile_complaints, \"serial line 1\")" \
 	"During symbol reading...serial line 1..." \
 	"serial line 1"
 
     # Add a second complaint, expect it
-    test_complaint "call complaint (&symfile_complaints, \"serial line 2\")" \
+    test_complaint \
+	"call complaint_internal (&symfile_complaints, \"serial line 2\")" \
 	"serial line 2..." \
 	"serial line 2"
 
@@ -109,12 +114,14 @@ proc test_short_complaints { } {
     gdb_test_exact "call clear_complaints (&symfile_complaints, 1, 1)" "" "short start"
 
     # Prime the system
-    test_complaint "call complaint (&symfile_complaints, \"short line 1\")" \
+    test_complaint \
+	"call complaint_internal (&symfile_complaints, \"short line 1\")" \
 	"short line 1..." \
 	"short line 1"
 
     # Add a second complaint, expect it
-    test_complaint "call complaint (&symfile_complaints, \"short line 2\")" \
+    test_complaint \
+	"call complaint_internal (&symfile_complaints, \"short line 2\")" \
 	"short line 2..." \
 	"short line 2"