[PATCH 39/40] fix compile_rx_or_error

[Tom Tromey <tromey@redhat.com>]

compile_rx_or_error looks like a constructor, but it can return NULL.
This patch changes it to remove the NULL return, making it work
like any other cleanup constructor.

This is a stylistic patch but I think it is also better for code to
follow the normal conventions.

	* probe.c (collect_probes): Check arguments for NULL before
	calling compile_rx_or_error.
	* utils.c (compile_rx_or_error): Require 'rx' to be non-NULL.
	Remove NULL return.
---
 gdb/probe.c | 9 ++++++---
 gdb/utils.c | 7 ++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/gdb/probe.c b/gdb/probe.c
index 05bdd1b..3086f4d 100644
--- a/gdb/probe.c
+++ b/gdb/probe.c
@@ -245,9 +245,12 @@ collect_probes (char *objname, char *provider, char *probe_name,
   cleanup = make_cleanup (VEC_cleanup (probe_p), &result);
 
   cleanup_temps = make_cleanup (null_cleanup, NULL);
-  compile_rx_or_error (&prov_pat, provider, _("Invalid provider regexp"));
-  compile_rx_or_error (&probe_pat, probe_name, _("Invalid probe regexp"));
-  compile_rx_or_error (&obj_pat, objname, _("Invalid object file regexp"));
+  if (provider != NULL)
+    compile_rx_or_error (&prov_pat, provider, _("Invalid provider regexp"));
+  if (probe_name != NULL)
+    compile_rx_or_error (&probe_pat, probe_name, _("Invalid probe regexp"));
+  if (objname != NULL)
+    compile_rx_or_error (&obj_pat, objname, _("Invalid object file regexp"));
 
   ALL_OBJFILES (objfile)
     {
diff --git a/gdb/utils.c b/gdb/utils.c
index c25dadf..fa54e10 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -1127,17 +1127,14 @@ get_regcomp_error (int code, regex_t *rx)
 }
 
 /* Compile a regexp and throw an exception on error.  This returns a
-   cleanup to free the resulting pattern on success.  If RX is NULL,
-   this does nothing and returns NULL.  */
+   cleanup to free the resulting pattern on success.  RX must not be
+   NULL.  */
 
 struct cleanup *
 compile_rx_or_error (regex_t *pattern, const char *rx, const char *message)
 {
   int code;
 
-  if (!rx)
-    return NULL;
-
   code = regcomp (pattern, rx, REG_NOSUB);
   if (code != 0)
     {
-- 
1.8.1.4