Re: [patch 2/2] Perform a namespace lookup at every block level

[Sami Wagiaalla <swagiaal at redhat dot com>]

> A recursive search must be performed. This patch provides that 
> functionality:

That implementation performed redundant searches. This problem is fixed
by this patch.


    2009-09-04  Sami Wagiaalla  <swagiaal@redhat.com>

    	* cp-namespace.c (cp_lookup_symbol_namespace): Added search_parent
    	argument.
    	* cp-support.h (cp_lookup_symbol_imports): Ditto.
    	* cp-namespace.c (cp_lookup_symbol_imports): Ditto.
    	Implement non parent search.
    	* valops.c (value_maybe_namespace_elt): Updated.

    2009-09-04  Sami Wagiaalla  <swagiaal@redhat.com>

    	* gdb.cp/namespace-stress.exp: New test.
    	* gdb.cp/namespace-stress.cc: New test file.

diff --git a/gdb/cp-namespace.c b/gdb/cp-namespace.c
index 909ec2c..eeaf851 100644
--- a/gdb/cp-namespace.c
+++ b/gdb/cp-namespace.c
@@ -46,7 +46,8 @@ static struct symbol *cp_lookup_symbol_imports (const char *scope,
                                                 const char *name,
                                                 const char *linkage_name,
                                                 const struct block *block,
-                                                const domain_enum domain);
+                                                const domain_enum domain,
+                                                const int search_parents);

 static struct symbol *cp_lookup_symbol_in_namespace (const char *namespace,
                                                      const char *name,
@@ -287,7 +288,7 @@ cp_lookup_symbol_nonlocal (const char *name,
   if ( sym != NULL)
     return sym;

-  return cp_lookup_symbol_namespace(scope, name, linkage_name, block, domain);
+  return cp_lookup_symbol_namespace(scope, name, linkage_name, block, domain, 1);
 }

 /* Searches for NAME in the current namespace, and by applying relevant import
@@ -299,14 +300,16 @@ cp_lookup_symbol_namespace (const char *scope,
                             const char *name,
                             const char *linkage_name,
                             const struct block *block,
-                            const domain_enum domain)
+                            const domain_enum domain,
+                            const int search_parents)
 {
   struct symbol *sym;

   /* Search for name in namespaces imported to this and parent blocks.  */
   while (block != NULL)
     {
-      sym = cp_lookup_symbol_imports(scope,name, linkage_name, block, domain);
+      sym = cp_lookup_symbol_imports(scope,name, linkage_name, block, domain,
+                                     search_parents );

       if (sym)
         return sym;
@@ -402,17 +405,33 @@ cp_lookup_symbol_in_namespace (const char *namespace,
 }

 /* Search for NAME by applying all import statements belonging
-   to BLOCK which are applicable in SCOPE.  */
+   to BLOCK which are applicable in SCOPE.
+   If SEARCH_PARENTS the search will include imports which are applicable in
+   parents of scopes.
+   Example:
+
+     namespace A{
+       using namespace X;
+       namespace B{
+         using namespace Y;
+       }
+     }
+
+   If SCOPE is "A::B" and SEARCH_PARENTS is true the imports of namespaces X
+   and Y will be considered. If SEARCH_PARENTS is false only the import of Y
+   is considered.  */

 static struct symbol *
 cp_lookup_symbol_imports (const char *scope,
                             const char *name,
                             const char *linkage_name,
                             const struct block *block,
-                            const domain_enum domain)
+                            const domain_enum domain,
+                            const int search_parents)
 {
   struct using_direct *current;
   struct symbol *sym;
+  int directive_match;

   /* First, try to find the symbol in the given namespace.  */
   sym = cp_lookup_symbol_in_namespace (scope, name, linkage_name, block,
@@ -429,9 +448,15 @@ cp_lookup_symbol_imports (const char *scope,
        current = current->next)
     {

+      directive_match = search_parents ?
+                        strncmp (scope, current->import_dest,
+                                 strlen(current->import_dest)) == 0 :
+                        strcmp (scope, current->import_dest) == 0;
+
       /* If the import destination is the current scope or one of its ancestors then
          it is applicable.  */
-      if (strncmp (scope, current->import_dest,
+      if (directive_match &&
+          strncmp (scope, current->import_dest,
                    strlen(current->import_dest)) == 0 &&
           !current->searched )
 	{
@@ -442,8 +467,8 @@ cp_lookup_symbol_imports (const char *scope,
 					    name,
 					    linkage_name,
 					    block,
-					    domain);
-	
+					    domain, 0);
+
 	  current->searched = 0;
 	  if (sym != NULL)
 	    return sym;
diff --git a/gdb/cp-support.h b/gdb/cp-support.h
index c9d53e5..348d7c9 100644
--- a/gdb/cp-support.h
+++ b/gdb/cp-support.h
@@ -108,7 +108,8 @@ extern struct symbol *cp_lookup_symbol_namespace (const char *namespace,
 						  const char *name,
 						  const char *linkage_name,
 						  const struct block *block,
-						  const domain_enum domain);
+						  const domain_enum domain,
+						  const int search_parents);

 extern struct type *cp_lookup_nested_type (struct type *parent_type,
 					   const char *nested_name,
diff --git a/gdb/testsuite/gdb.cp/namespace-stress.cc b/gdb/testsuite/gdb.cp/namespace-stress.cc
new file mode 100644
index 0000000..f34083e
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/namespace-stress.cc
@@ -0,0 +1,60 @@
+
+namespace A{ int x; }
+namespace B{ int x; }
+namespace C{ int x; }
+namespace D{ int x; }
+namespace E{ int x; }
+namespace F{ int x; }
+namespace G{ int x; }
+namespace H{ int x; }
+namespace I{ int x; }
+namespace J{ int x; }
+namespace K{ int x; }
+namespace L{ int x; }
+namespace M{ int x; }
+namespace N{ int x; }
+namespace O{ int x; }
+namespace P{ int x; }
+namespace Q{ int x; }
+namespace R{ int x; }
+namespace S{ int x; }
+namespace T{ int x; }
+namespace U{ int x; }
+namespace V{ int x; }
+namespace W{ int x; }
+namespace X{ int x; }
+namespace Y{ int x; }
+namespace Z{ int x; }
+
+
+int main(){
+
+  using namespace A;
+  using namespace B;
+  using namespace C;
+  using namespace D;
+  using namespace E;
+  using namespace F;
+  using namespace G;
+  using namespace H;
+  using namespace I;
+  using namespace J;
+  using namespace K;
+  using namespace L;
+  using namespace M;
+  using namespace N;
+  using namespace O;
+  using namespace P;
+  using namespace Q;
+  using namespace R;
+  using namespace S;
+  using namespace T;
+  using namespace U;
+  using namespace V;
+  using namespace W;
+  using namespace X;
+  using namespace Y;
+  using namespace Z;
+
+  return 0;
+}
\ No newline at end of file
diff --git a/gdb/testsuite/gdb.cp/namespace-stress.exp b/gdb/testsuite/gdb.cp/namespace-stress.exp
new file mode 100644
index 0000000..36e0628
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/namespace-stress.exp
@@ -0,0 +1,50 @@
+# Copyright 2008 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+set testfile namespace-stress
+set srcfile ${testfile}.cc
+set binfile ${objdir}/${subdir}/${testfile}
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
+    untested "Couldn't compile test program"
+    return -1
+}
+
+if [get_compiler_info ${binfile}] {
+    return -1;
+}
+
+# Get things started.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+if ![runto_main] then {
+    perror "couldn't run to breakpoint main"
+    continue
+}
+
+############################################
+# Test that the search can fail efficiently
+
+gdb_test "print y" "No symbol \"y\" in current context."
diff --git a/gdb/valops.c b/gdb/valops.c
index 5e5c4ed..3448b4a 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -2754,7 +2754,7 @@ value_maybe_namespace_elt (const struct type *curtype,

   sym = cp_lookup_symbol_namespace (namespace_name, name, NULL,
 				    get_selected_block (0),
-				    VAR_DOMAIN);
+				    VAR_DOMAIN,1);

   if (sym == NULL)
     return NULL;