Add new search_symbols_multiple API

This patch adds a new symbol searching API based on linespec.c's parser
implementation.  This allows users to find "all* matching symbols instead
of the first found match (a la lookup_symbol).

gdb/ChangeLog:

	* linespec.c (collect_info::add_symbol): Make virtual.
	(struct symbol_searcher_collect_info): New struct.
	(symbol_searcher::find_all_symbols): New method.
	* symtab.h (class symbol_searcher): New class.

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2018-08-29  Keith Seitz  <keiths@redhat.com>
+
+	* linespec.c (collect_info::add_symbol): Make virtual.
+	(struct symbol_searcher_collect_info): New struct.
+	(symbol_searcher::find_all_symbols): New method.
+	* symtab.h (class symbol_searcher): New class.
+
 2018-08-29  Keith Seitz  <keiths@redhat.com>
 
 	* linespec.c (struct linespec) <function_symbols, label_symbols>:

gdb/linespec.c

@@ -199,7 +199,7 @@ struct collect_info
   } result;
 
   /* Possibly add a symbol to the results.  */
-  bool add_symbol (block_symbol *bsym);
+  virtual bool add_symbol (block_symbol *bsym);
 };
 
 bool
@@ -214,6 +214,21 @@ collect_info::add_symbol (block_symbol *bsym)
   return true;
 }
 
+/* Custom collect_info for symbol_searcher.  */
+
+struct symbol_searcher_collect_info
+  : collect_info
+{
+  bool add_symbol (block_symbol *bsym) override
+  {
+    /* Add everything.  */
+    this->result.symbols->push_back (*bsym);
+
+    /* Continue iterating.  */
+    return true;
+  }
+};
+
 /* Token types  */
 
 enum ls_token_type
@@ -3876,6 +3891,36 @@ symtabs_from_filename (const char *filename,
   return result;
 }
 
+/* See symtab.h.  */
+
+void
+symbol_searcher::find_all_symbols (const std::string &name,
+				   const struct language_defn *language,
+				   enum search_domain search_domain,
+				   std::vector<symtab *> *search_symtabs,
+				   struct program_space *search_pspace)
+{
+  symbol_searcher_collect_info info;
+  struct linespec_state state;
+
+  memset (&state, 0, sizeof (state));
+  state.language = language;
+  info.state = &state;
+
+  info.result.symbols = &m_symbols;
+  info.result.minimal_symbols = &m_minimal_symbols;
+  std::vector<symtab *> all_symtabs;
+  if (search_symtabs == nullptr)
+    {
+      all_symtabs.push_back (nullptr);
+      search_symtabs = &all_symtabs;
+    }
+  info.file_symtabs = search_symtabs;
+
+  add_matching_symbols_to_info (name.c_str (), symbol_name_match_type::WILD,
+				search_domain, &info, search_pspace);
+}
+
 /* Look up a function symbol named NAME in symtabs FILE_SYMTABS.  Matching
    debug symbols are returned in SYMBOLS.  Matching minimal symbols are
    returned in MINSYMS.  */

gdb/symtab.h

@@ -2185,4 +2185,47 @@ void completion_list_add_name (completion_tracker &tracker,
 			       const lookup_name_info &lookup_name,
 			       const char *text, const char *word);
 
+/* A simple symbol searching class.  */
+
+class symbol_searcher
+{
+public:
+  /* Returns the symbols found for the search.  */
+  const std::vector<block_symbol> &
+  matching_symbols () const
+  {
+    return m_symbols;
+  }
+
+  /* Returns the minimal symbols found for the search.  */
+  const std::vector<bound_minimal_symbol> &
+  matching_msymbols () const
+  {
+    return m_minimal_symbols;
+  }
+
+  /* Search for all symbols named NAME in LANGUAGE with DOMAIN, restricting
+     search to FILE_SYMTABS and SEARCH_PSPACE, both of which may be NULL
+     to search all symtabs and program spaces.  */
+  void find_all_symbols (const std::string &name,
+			 const struct language_defn *language,
+			 enum search_domain search_domain,
+			 std::vector<symtab *> *search_symtabs,
+			 struct program_space *search_pspace);
+
+  /* Reset this object to perform another search.  */
+  void reset ()
+  {
+    m_symbols.clear ();
+    m_minimal_symbols.clear ();
+  }
+
+private:
+  /* Matching debug symbols.  */
+  std::vector<block_symbol>  m_symbols;
+
+  /* Matching non-debug symbols.  */
+  std::vector<bound_minimal_symbol> m_minimal_symbols;
+};
+
 #endif /* !defined(SYMTAB_H) */