Introduce language_defn::lookup_symbol_local

This introduces the new method language_defn::lookup_symbol_local, and
then changes lookup_symbol_local to use it.  This removes an explicit
language check from this function, and makes it easier for other
languages to hook into this code.

gdb/c-lang.c

@@ -1014,6 +1014,17 @@ class cplus_language : public language_defn
 
   /* See language.h.  */
 
+  struct block_symbol lookup_symbol_local
+       (const char *scope,
+	const char *name,
+	const struct block *block,
+	const domain_search_flags domain) const override
+  {
+    return cp_lookup_symbol_imports (scope, name, block, domain);
+  }
+
+  /* See language.h.  */
+
   struct block_symbol lookup_symbol_nonlocal
 	(const char *name, const struct block *block,
 	 const domain_search_flags domain) const override

gdb/f-lang.c

@@ -1711,6 +1711,17 @@ f_language::search_name_hash (const char *name) const
 
 /* See language.h.  */
 
+struct block_symbol
+f_language::lookup_symbol_local (const char *scope,
+				 const char *name,
+				 const struct block *block,
+				 const domain_search_flags domain) const
+{
+  return cp_lookup_symbol_imports (scope, name, block, domain);
+}
+
+/* See language.h.  */
+
 struct block_symbol
 f_language::lookup_symbol_nonlocal (const char *name,
 				    const struct block *block,

gdb/f-lang.h

@@ -140,6 +140,14 @@ class f_language : public language_defn
 
   /* See language.h.  */
 
+  struct block_symbol lookup_symbol_local
+       (const char *scope,
+	const char *name,
+	const struct block *block,
+	const domain_search_flags domain) const override;
+
+  /* See language.h.  */
+
   struct block_symbol lookup_symbol_nonlocal
 	(const char *name, const struct block *block,
 	 const domain_search_flags domain) const override;

gdb/language.h

@@ -507,6 +507,23 @@ struct language_defn
       (tracker, mode, name_match_type, text, word, "", code);
   }
 
+  /* This is called by lookup_local_symbol after checking a block.  It
+     can be used by a language to augment the local lookup, for
+     instance for searching imported namespaces.  SCOPE is the current
+     scope (from block::scope), NAME is the name being searched for,
+     BLOCK is the block being searched, and DOMAIN is the search
+     domain.  Returns a block symbol, or an empty block symbol if not
+     found.  */
+
+  virtual struct block_symbol lookup_symbol_local
+       (const char *scope,
+	const char *name,
+	const struct block *block,
+	const domain_search_flags domain) const
+  {
+    return {};
+  }
+
   /* This is a function that lookup_symbol will call when it gets to
      the part of symbol lookup where C looks up static and global
      variables.  This default implements the basic C lookup rules.  */

gdb/symtab.c

@@ -93,7 +93,7 @@ struct block_symbol lookup_local_symbol (const char *name,
 					 symbol_name_match_type match_type,
 					 const struct block *block,
 					 const domain_search_flags domain,
-					 enum language language);
+					 const struct language_defn *langdef);
 
 static struct block_symbol
   lookup_symbol_in_objfile (struct objfile *objfile,
@@ -2140,10 +2140,12 @@ lookup_symbol_aux (const char *name, symbol_name_match_type match_type,
   if (is_a_field_of_this != NULL)
     memset (is_a_field_of_this, 0, sizeof (*is_a_field_of_this));
 
+  langdef = language_def (language);
+
   /* Search specified block and its superiors.  Don't search
      STATIC_BLOCK or GLOBAL_BLOCK.  */
 
-  result = lookup_local_symbol (name, match_type, block, domain, language);
+  result = lookup_local_symbol (name, match_type, block, domain, langdef);
   if (result.symbol != NULL)
     {
       symbol_lookup_debug_printf
@@ -2155,8 +2157,6 @@ lookup_symbol_aux (const char *name, symbol_name_match_type match_type,
   /* If requested to do so by the caller and if appropriate for LANGUAGE,
      check to see if NAME is a field of `this'.  */
 
-  langdef = language_def (language);
-
   /* Don't do this check if we are searching for a struct.  It will
      not be found by check_field, but will be found by other
      means.  */
@@ -2217,7 +2217,7 @@ lookup_local_symbol (const char *name,
 		     symbol_name_match_type match_type,
 		     const struct block *block,
 		     const domain_search_flags domain,
-		     enum language language)
+		     const struct language_defn *langdef)
 {
   if (block == nullptr)
     return {};
@@ -2242,14 +2242,10 @@ lookup_local_symbol (const char *name,
 	    return (struct block_symbol) {sym, block};
 	}
 
-      if (language == language_cplus || language == language_fortran)
-	{
-	  struct block_symbol blocksym
-	    = cp_lookup_symbol_imports (scope, name, block, domain);
-
-	  if (blocksym.symbol != NULL)
-	    return blocksym;
-	}
+      struct block_symbol blocksym
+	= langdef->lookup_symbol_local (scope, name, block, domain);
+      if (blocksym.symbol != nullptr)
+	return blocksym;
 
       if (block->inlined_p ())
 	break;