[PATCH v3 3/3] gdb: extend the [[N]]::foo syntax for files

[Guinevere Larsen <guinevere@redhat.com>]

This commit implements the missing support for [[N]]::'file.c'::var
syntax that was skipped on the previous commit.

This is done by adding a new value to the global parser_state, so that
the classify_name function can restrict its search for file names to the
specified linker namespace.  It had to be done this way because if the
logic was contained on the newly added "block: block COLONCOLON
FILENAME" rule, we would not have the name to rerun the search. Because
of that, the new rule only exists to make sure this is only used in the
intended syntax.  This commit also adds a link to the solib_ops relevant
to the expression being parsed, as a way to identify if linker
namespaces are supported; this could be achieved by guarding the search
functions instead, but I think that this is more reliable.

The new rule uses "block" rather than a linker namespace specific token,
because if we allowed that token to also reduce into block, the new rule
would never be triggered as the simple reduction would be preferred. If
we didn't allow the linker namespace to reduce into block, the rest of
the syntaxes for [[N]]::foo would be more involved, so the option in
this commit seemed like the simplest solution.

The parser_state changes were not used for the previous commit because
the lookup_symbol calls would lead to an even more intrusive change for
no real gain, since the search would be rerun any way. There is an
argument to be made that the results could be different if only
namespace had a type and another had a variable, but a situation where
that significantly changes the result is quite unlikely, I think.
---
 gdb/c-exp.y                               | 10 +++++++-
 gdb/linespec.c                            |  4 +--
 gdb/parse.c                               |  3 ++-
 gdb/parser-defs.h                         | 30 +++++++++++++++++++++--
 gdb/rust-parse.c                          |  3 ++-
 gdb/symtab.c                              | 24 ++++++++++++++----
 gdb/symtab.h                              |  7 +++++-
 gdb/testsuite/gdb.base/dlmopen-ns-ids.exp |  7 ++++++
 8 files changed, 75 insertions(+), 13 deletions(-)

diff --git a/gdb/c-exp.y b/gdb/c-exp.y
index 1de2ee6bfc6..4f4e36c9789 100644
--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -1084,6 +1084,7 @@ block	:	BLOCKNAME
 			{
 			    $$.search_namespace = true;
 			    $$.namespace_val = $2.val;
+			    pstate->set_linker_namespace ($2.val);
 			}
 	;
 
@@ -1106,6 +1107,12 @@ block	:	block COLONCOLON name
 			  $$.b_val = tem.symbol->value_block ();
 			  $$.search_namespace = false;
 			}
+	|	block COLONCOLON FILENAME
+			{
+			    if (!$1.search_namespace)
+				error (_("Filename must be the first part of the expression"));
+			    $$ = $3;
+			}
 	;
 
 variable:	name_not_typename ENTRY
@@ -3116,7 +3123,8 @@ classify_name (struct parser_state *par_state, const struct block *block,
 	  || is_quoted_name)
 	{
 	  /* See if it's a file name. */
-	  if (auto symtab = lookup_symtab (current_program_space, copy.c_str ());
+	  if (auto symtab = lookup_symtab (current_program_space, copy.c_str (),
+					   par_state->get_linker_namespace ());
 	      symtab != nullptr)
 	    {
 	      yylval.bval.b_val
diff --git a/gdb/linespec.c b/gdb/linespec.c
index b59c0553c34..9fde76d6c80 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -3658,11 +3658,11 @@ collect_symtabs_from_filename (const char *file,
 	  if (pspace->executing_startup)
 	    continue;
 
-	  iterate_over_symtabs (pspace, file, collector);
+	  iterate_over_symtabs (pspace, file, -1, collector);
 	}
     }
   else
-    iterate_over_symtabs (search_pspace, file, collector);
+    iterate_over_symtabs (search_pspace, file, -1, collector);
 
   return collector.release_symtabs ();
 }
diff --git a/gdb/parse.c b/gdb/parse.c
index 64653c8ae6e..6edd9058dcb 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -421,7 +421,8 @@ parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
 
   parser_state ps (lang, get_current_arch (), expression_context_block,
 		   expression_context_pc, flags, *stringptr,
-		   completer != nullptr, tracker);
+		   completer != nullptr, tracker,
+		   current_program_space->solib_ops ());
 
   scoped_restore_current_language lang_saver (lang->la_language);
 
diff --git a/gdb/parser-defs.h b/gdb/parser-defs.h
index ff4ab6a09de..9de3b6f7d9c 100644
--- a/gdb/parser-defs.h
+++ b/gdb/parser-defs.h
@@ -26,6 +26,7 @@
 #include "expression.h"
 #include "symtab.h"
 #include "expop.h"
+#include "solib.h"
 
 struct block;
 struct language_defn;
@@ -147,7 +148,8 @@ struct parser_state : public expr_builder
 		parser_flags flags,
 		const char *input,
 		bool completion,
-		innermost_block_tracker *tracker)
+		innermost_block_tracker *tracker,
+		solib_ops *ops)
     : expr_builder (lang, gdbarch),
       expression_context_block (context_block),
       expression_context_pc (context_pc),
@@ -157,7 +159,8 @@ struct parser_state : public expr_builder
       comma_terminates ((flags & PARSER_COMMA_TERMINATES) != 0),
       parse_completion (completion),
       void_context_p ((flags & PARSER_VOID_CONTEXT) != 0),
-      debug ((flags & PARSER_DEBUG) != 0)
+      debug ((flags & PARSER_DEBUG) != 0),
+      m_solib_ops (ops)
   {
   }
 
@@ -263,6 +266,19 @@ struct parser_state : public expr_builder
     push (expr::make_operation<T> (std::move (lhs), std::move (rhs)));
   }
 
+  void set_linker_namespace (LONGEST ns_id)
+  {
+    if (m_solib_ops->supports_namespaces ())
+      linker_namespace = ns_id;
+    else
+      error (_("Linker namespaces are not supported"));
+  }
+
+  LONGEST get_linker_namespace ()
+  {
+    return linker_namespace;
+  }
+
   /* Function called from the various parsers' yyerror functions to throw
      an error.  The error will include a message identifying the location
      of the error within the current expression.  */
@@ -323,6 +339,16 @@ struct parser_state : public expr_builder
 
   /* Stack of operations.  */
   std::vector<expr::operation_up> m_operations;
+
+  /* If the expression is being restricted to a specific namespace, this is
+     where that information is stored for the block lookup.  It should be
+     accessed through setter/getters to ensure that the linker namespace is
+     only set when the gdbarch supports it.  */
+  LONGEST linker_namespace = -1;
+
+  /* Used to figure out if an inferior is capable of handling linker
+     namespaces at all.  */
+  solib_ops *m_solib_ops;
 };
 
 /* A string token, either a char-string or bit-string.  Char-strings are
diff --git a/gdb/rust-parse.c b/gdb/rust-parse.c
index ef640056051..752b89f4af4 100644
--- a/gdb/rust-parse.c
+++ b/gdb/rust-parse.c
@@ -2315,7 +2315,8 @@ rust_lex_tests (void)
 {
   /* Set up dummy "parser", so that rust_type works.  */
   parser_state ps (language_def (language_rust), current_inferior ()->arch (),
-		   nullptr, 0, 0, nullptr, 0, nullptr);
+		   nullptr, 0, 0, nullptr, 0, nullptr,
+		   current_program_space->solib_ops ());
   rust_parser parser (&ps);
 
   rust_lex_test_one (&parser, "", 0);
diff --git a/gdb/symtab.c b/gdb/symtab.c
index b4db8275580..638142fe633 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -703,6 +703,7 @@ iterate_over_some_symtabs (const char *name,
 
 void
 iterate_over_symtabs (program_space *pspace, const char *name,
+		      LONGEST linker_ns,
 		      gdb::function_view<bool (symtab *)> callback)
 {
   gdb::unique_xmalloc_ptr<char> real_path;
@@ -715,7 +716,20 @@ iterate_over_symtabs (program_space *pspace, const char *name,
       gdb_assert (IS_ABSOLUTE_PATH (real_path.get ()));
     }
 
-  for (objfile *objfile : pspace->objfiles ())
+  std::vector<objfile *> objfiles_to_search;
+  if (linker_ns >= 0)
+    {
+      gdb_assert (pspace->solib_ops ()->supports_namespaces ());
+      objfiles_to_search
+	= get_objfiles_in_linker_namespace (linker_ns, pspace);
+    }
+  else
+    {
+      for (objfile *objf : pspace->objfiles ())
+	objfiles_to_search.push_back (objf);
+    }
+
+  for (objfile *objfile : objfiles_to_search)
     if (iterate_over_some_symtabs (name, real_path.get (),
 				   objfile->compunit_symtabs, nullptr,
 				   callback))
@@ -723,7 +737,7 @@ iterate_over_symtabs (program_space *pspace, const char *name,
 
   /* Same search rules as above apply here, but now we look through the
      psymtabs.  */
-  for (objfile *objfile : pspace->objfiles ())
+  for (objfile *objfile : objfiles_to_search)
     if (objfile->map_symtabs_matching_filename (name, real_path.get (),
 						callback))
       return;
@@ -732,11 +746,11 @@ iterate_over_symtabs (program_space *pspace, const char *name,
 /* See symtab.h.  */
 
 symtab *
-lookup_symtab (program_space *pspace, const char *name)
+lookup_symtab (program_space *pspace, const char *name, LONGEST linker_ns)
 {
   struct symtab *result = NULL;
 
-  iterate_over_symtabs (pspace, name, [&] (symtab *symtab)
+  iterate_over_symtabs (pspace, name, linker_ns, [&] (symtab *symtab)
     {
       result = symtab;
       return true;
@@ -6359,7 +6373,7 @@ collect_file_symbol_completion_matches (completion_tracker &tracker,
 
   /* Go through symtabs for SRCFILE and check the externs and statics
      for symbols which match.  */
-  iterate_over_symtabs (current_program_space, srcfile, [&] (symtab *s)
+  iterate_over_symtabs (current_program_space, srcfile, -1, [&] (symtab *s)
     {
       add_symtab_completions (s->compunit (),
 			      tracker, mode, lookup_name,
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 27acc70bf1d..8ab73e9b73c 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -2090,7 +2090,8 @@ const char *multiple_symbols_select_mode (void);
 
 /* Lookup a symbol table in PSPACE by source file name.  */
 
-extern symtab *lookup_symtab (program_space *pspace, const char *name);
+extern symtab *lookup_symtab (program_space *pspace, const char *name,
+			      LONGEST linker_ns = -1);
 
 /* An object of this type is passed as the 'is_a_field_of_this'
    argument to lookup_symbol and lookup_symbol_in_language.  */
@@ -2824,10 +2825,14 @@ bool iterate_over_some_symtabs (const char *name,
    psymtabs.  *If* there is no '/' in the name, a match after a '/' in the
    symtab filename will also work.
 
+   If LINKER_NS is 0 or greater, only the objfiles in the provided linker
+   namespace will be iterated over.
+
    Call CALLBACK with each symtab that is found.  If CALLBACK returns
    true, the search stops.  */
 
 void iterate_over_symtabs (program_space *pspace, const char *name,
+			   LONGEST linker_ns,
 			   gdb::function_view<bool (symtab *)> callback);
 
 std::vector<CORE_ADDR> find_pcs_for_symtab_line
diff --git a/gdb/testsuite/gdb.base/dlmopen-ns-ids.exp b/gdb/testsuite/gdb.base/dlmopen-ns-ids.exp
index 303595faee5..ac6d1c44aa6 100644
--- a/gdb/testsuite/gdb.base/dlmopen-ns-ids.exp
+++ b/gdb/testsuite/gdb.base/dlmopen-ns-ids.exp
@@ -265,6 +265,7 @@ proc_with_prefix test_print_namespace_symbol {} {
     gdb_breakpoint "change_global" allow-pending
     gdb_continue_to_breakpoint "change_global"
 
+    set ns0 [ns_id_for_command 0]
     set ns1 [ns_id_for_command 1]
     set ns2 [ns_id_for_command 2]
 
@@ -292,6 +293,12 @@ proc_with_prefix test_print_namespace_symbol {} {
     # returning a random one, we just say we didn't find one.
     gdb_test "print gdb_dlmopen_glob" \
 	"No symbol .gdb_dlmopen_glob. in the current linker namespace."
+
+    # Minimal testing for finding files in namespaces.
+    gdb_test "print ${ns1}::'${::srcfile_lib}'::gdb_dlmopen_glob" \
+	".* = 2"
+    gdb_test "print ${ns0}::'${::srcfile_lib}'::gdb_dlmopen_glob" \
+	"No function .${::srcfile_lib}. in specified context."
 }
 
 test_info_shared
-- 
2.49.0