Re: [patch] Add namespace aliasing support.

[Sami Wagiaalla <swagiaal at redhat dot com>]

Thanks for the prompt review. Here is the corrected patch:

PR gdb/7935:
2010-02-01  Sami Wagiaalla  <swagiaal@redhat.com>

   * cp-support.h: Added char* alias element to using_direct data
   struct.
   (cp_add_using): Added char* alias argument.
   (cp_add_using_directive): Ditto.
   * cp-namespace.c: Updated with the above changes.
   (cp_lookup_symbol_imports): Check for aliases.
   * dwarf2read.c (read_import_statement): Figure out local alias
   for the import and pass it on to cp_add_using.
   (read_namespace): Pass alias argument to cp_add_using.

2010-02-01  Sami Wagiaalla  <swagiaal@redhat.com>

   * gdb.cp/namespace-using.exp: Removed kfail; bug has been fixed.



diff --git a/gdb/cp-namespace.c b/gdb/cp-namespace.c
index 8ca9c20..e0eb151 100644
--- a/gdb/cp-namespace.c
+++ b/gdb/cp-namespace.c
@@ -117,7 +117,7 @@ cp_scan_for_anonymous_namespaces (const struct symbol *symbol)
 		 anonymous namespace.  So add symbols in it to the
 		 namespace given by the previous component if there is
 		 one, or to the global namespace if there isn't.  */
-	      cp_add_using_directive (dest, src);
+	      cp_add_using_directive (dest, src, NULL);
 	    }
 	  /* The "+ 2" is for the "::".  */
 	  previous_component = next_component + 2;
@@ -132,7 +132,7 @@ cp_scan_for_anonymous_namespaces (const struct symbol *symbol)
    has already been added, don't add it twice.  */
 
 void
-cp_add_using_directive (const char *dest, const char *src)
+cp_add_using_directive (const char *dest, const char *src, const char *alias)
 {
   struct using_direct *current;
   struct using_direct *new;
@@ -146,7 +146,7 @@ cp_add_using_directive (const char *dest, const char *src)
 	return;
     }
 
-  using_directives = cp_add_using (dest, src, using_directives);
+  using_directives = cp_add_using (dest, src, alias, using_directives);
 
 }
 
@@ -198,8 +198,10 @@ cp_is_anonymous (const char *namespace)
 	  != NULL);
 }
 
-/* Create a new struct using direct which imports the namespace SRC
-   into the scope DEST.
+/* Create a new struct using direct which imports the namespace SRC into the
+   scope DEST.  ALIAS is the name of the imported namespace in the current
+   scope.  If ALIAS is an empty string then the namespace is known by its
+   original name.
    Set its next member in the linked list to NEXT; allocate all memory
    using xmalloc.  It copies the strings, so NAME can be a temporary
    string.  */
@@ -207,6 +209,7 @@ cp_is_anonymous (const char *namespace)
 struct using_direct *
 cp_add_using (const char *dest,
               const char *src,
+              const char *alias,
 	      struct using_direct *next)
 {
   struct using_direct *retval;
@@ -214,6 +217,12 @@ cp_add_using (const char *dest,
   retval = xmalloc (sizeof (struct using_direct));
   retval->import_src = savestring (src, strlen(src));
   retval->import_dest = savestring (dest, strlen(dest));
+
+  if (alias != NULL)
+    retval->alias = savestring (alias, strlen (alias));
+  else
+    retval->alias = NULL;
+
   retval->next = next;
   retval->searched = 0;
 
@@ -344,13 +353,28 @@ cp_lookup_symbol_imports (const char *scope,
 	current->searched = 1;
 	searched_cleanup = make_cleanup (reset_directive_searched, current);
 
-	sym = cp_lookup_symbol_namespace (current->import_src,
-	                                  name,
-	                                  linkage_name,
-	                                  block,
-	                                  domain,
-	                                  0);
-
+	if (current->alias != NULL && strcmp (name, current->alias) == 0)
+	  /* If the import is creating an alias and the alias matches the
+	     sought name.  Pass current->import_src as the NAME to direct the
+	     search towards the aliased namespace.  */
+	  {
+	    sym = cp_lookup_symbol_in_namespace (scope,
+	                                         current->import_src,
+	                                         linkage_name,
+	                                         block,
+	                                         domain);
+	  }
+	else if (current->alias == NULL)
+	  {
+	    /* If this import statement creates no alias, pass current->inner as
+               NAMESPACE to direct the search towards the imported namespace.  */
+	    sym = cp_lookup_symbol_imports (current->import_src,
+	                                    name,
+	                                    linkage_name,
+	                                    block,
+	                                    domain,
+	                                    0);
+	  }
 	current->searched = 0;
 	discard_cleanups (searched_cleanup);
 
diff --git a/gdb/cp-support.h b/gdb/cp-support.h
index 33b1b44..44d6ad4 100644
--- a/gdb/cp-support.h
+++ b/gdb/cp-support.h
@@ -38,14 +38,20 @@ struct demangle_component;
 
 /* This struct is designed to store data from using directives.  It
    says that names from namespace IMPORT_SRC should be visible within
-   namespace IMPORT_DEST. IMPORT_DEST should always be a strict initial
-   substring of IMPORT_SRC. These form a linked list; NEXT is the next element
-   of the list.  */
+   namespace IMPORT_DEST.  These form a linked list; NEXT is the next element
+   of the list.  ALIAS is set to a non empty string if the imported namespace
+   has been aliased.
+   Eg:
+       namespace C=A::B;
+*/
 
 struct using_direct
 {
   char *import_src;
   char *import_dest;
+
+  char *alias;
+
   struct using_direct *next;
 
   /* Used during import search to temporarily mark this node as searched.  */
@@ -82,10 +88,12 @@ extern int cp_validate_operator (const char *input);
 extern int cp_is_anonymous (const char *namespace);
 
 extern void cp_add_using_directive (const char *dest,
-                                    const char *src);
+                                    const char *src,
+                                    const char *alias);
 
 extern struct using_direct *cp_add_using (const char *dest,
                                           const char *src,
+                                          const char *alias,
 					  struct using_direct *next);
 
 extern void cp_initialize_namespace (void);
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 2f671ca..46b9efc 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -3385,6 +3385,8 @@ read_import_statement (struct die_info *die, struct dwarf2_cu *cu)
   struct dwarf2_cu *imported_cu;
   const char *imported_name;
   const char *imported_name_prefix;
+  char *import_alias;
+
   const char *import_prefix;
   char *canonical_name;
 
@@ -3436,7 +3438,8 @@ read_import_statement (struct die_info *die, struct dwarf2_cu *cu)
       return;
     }
 
-  /* FIXME: dwarf2_name (die); for the local name after import.  */
+  /* Figure out the local name after import.  */
+  import_alias = dwarf2_name (die, cu);
 
   /* Figure out where the statement is being imported to.  */
   import_prefix = determine_prefix (die, cu);
@@ -3447,7 +3450,8 @@ read_import_statement (struct die_info *die, struct dwarf2_cu *cu)
 
   if (strlen (imported_name_prefix) > 0)
     {
-      canonical_name = alloca (strlen (imported_name_prefix) + 2 + strlen (imported_name) + 1);
+      canonical_name = alloca (strlen (imported_name_prefix)
+                               + 2 + strlen (imported_name) + 1);
       strcpy (canonical_name, imported_name_prefix);
       strcat (canonical_name, "::");
       strcat (canonical_name, imported_name);
@@ -3458,7 +3462,10 @@ read_import_statement (struct die_info *die, struct dwarf2_cu *cu)
       strcpy (canonical_name, imported_name);
     }
 
-  using_directives = cp_add_using (import_prefix,canonical_name, using_directives);
+  using_directives = cp_add_using (import_prefix,
+                                   canonical_name,
+                                   import_alias,
+                                   using_directives);
 }
 
 static void
@@ -5616,7 +5623,7 @@ read_namespace (struct die_info *die, struct dwarf2_cu *cu)
       if (is_anonymous)
 	{
 	  const char *previous_prefix = determine_prefix (die, cu);
-	  cp_add_using_directive (previous_prefix, TYPE_NAME (type));
+	  cp_add_using_directive (previous_prefix, TYPE_NAME (type), NULL);
 	}
     }
 
diff --git a/gdb/testsuite/gdb.cp/nsusing.exp b/gdb/testsuite/gdb.cp/nsusing.exp
index bd115c4..72a616e 100644
--- a/gdb/testsuite/gdb.cp/nsusing.exp
+++ b/gdb/testsuite/gdb.cp/nsusing.exp
@@ -116,14 +116,11 @@ if ![runto marker2] then {
     continue
 }
 
-setup_kfail "gdb/7935" "*-*-*"
 gdb_test "print B::_a" "= 1"
 
-setup_kfail "gdb/7935" "*-*-*"
 gdb_test "print _a" "No symbol \"_a\" in current context." \
     "print _a in namespace alias scope"
 
-setup_kfail "gdb/7935" "*-*-*"
 gdb_test "print x" "No symbol \"x\" in current context." \
     "print x in namespace alias scope"

Attachment: namespace-alias.patch
Description: Text document