Switch objfile to hold a list of psymbol readers

This changes objfile::qf to be a forward_list, and then updates all
the uses to iterate over the list.  Note that there is still only ever
a single element in the list; this is handled by clearing the list
whenever an object is added.

gdb/ChangeLog
2021-03-20  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (dwarf2_build_psymtabs): Update.
	* symfile.c (syms_from_objfile_1, reread_symbols): Update.
	* symfile-debug.c (objfile::has_partial_symbols)
	(objfile::find_last_source_symtab)
	(objfile::forget_cached_source_info)
	(objfile::map_symtabs_matching_filename, objfile::lookup_symbol)
	(objfile::print_stats, objfile::dump)
	(objfile::expand_symtabs_for_function)
	(objfile::expand_all_symtabs)
	(objfile::expand_symtabs_with_fullname)
	(objfile::map_matching_symbols)
	(objfile::expand_symtabs_matching)
	(objfile::find_pc_sect_compunit_symtab)
	(objfile::map_symbol_filenames)
	(objfile::find_compunit_symtab_by_address)
	(objfile::lookup_global_symbol_language)
	(objfile::require_partial_symbols): Update.
	* psymtab.c (maintenance_print_psymbols)
	(maintenance_info_psymtabs, maintenance_check_psymtabs): Update.
	* objfiles.h (struct objfile) <qf>: Now a forward_list.
	* objfiles.c (objfile_relocate1): Update.
	* elfread.c (elf_symfile_read): Update.

1 files changed, 85 insertions, 52 deletions

diff --git a/gdb/symfile-debug.c b/gdb/symfile-debug.c
index 9997453..3daede8 100644
--- a/gdb/symfile-debug.c
+++ b/gdb/symfile-debug.c
@@ -80,12 +80,16 @@ objfile::has_partial_symbols ()
      them, then that is an indication that they are in fact available.  Without
      this function the symbols may have been already read in but they also may
      not be present in this objfile.  */
-  if ((flags & OBJF_PSYMTABS_READ) == 0
-      && qf != nullptr
-      && qf->can_lazily_read_symbols ())
-    retval = true;
-  else if (qf != nullptr)
-    retval = qf->has_symbols (this);
+  for (const auto &iter : qf)
+    {
+      if ((flags & OBJF_PSYMTABS_READ) == 0
+	  && iter->can_lazily_read_symbols ())
+	retval = true;
+      else
+	retval = iter->has_symbols (this);
+      if (retval)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog, "qf->has_symbols (%s) = %d\n",
@@ -103,8 +107,12 @@ objfile::find_last_source_symtab ()
     fprintf_filtered (gdb_stdlog, "qf->find_last_source_symtab (%s)\n",
 		      objfile_debug_name (this));
 
-  if (qf != nullptr)
-    retval = qf->find_last_source_symtab (this);
+  for (const auto &iter : qf)
+    {
+      retval = iter->find_last_source_symtab (this);
+      if (retval != nullptr)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog, "qf->find_last_source_symtab (...) = %s\n",
@@ -120,8 +128,8 @@ objfile::forget_cached_source_info ()
     fprintf_filtered (gdb_stdlog, "qf->forget_cached_source_info (%s)\n",
 		      objfile_debug_name (this));
 
-  if (qf != nullptr)
-    qf->forget_cached_source_info (this);
+  for (const auto &iter : qf)
+    iter->forget_cached_source_info (this);
 }
 
 bool
@@ -138,9 +146,13 @@ objfile::map_symtabs_matching_filename
 		      host_address_to_string (&callback));
 
   bool retval = false;
-  if (qf != nullptr)
-    retval = (qf->map_symtabs_matching_filename
-	      (this, name, real_path, callback));
+  for (const auto &iter : qf)
+    {
+      retval = (iter->map_symtabs_matching_filename
+		(this, name, real_path, callback));
+      if (retval)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog,
@@ -161,8 +173,12 @@ objfile::lookup_symbol (block_enum kind, const char *name, domain_enum domain)
 		      objfile_debug_name (this), kind, name,
 		      domain_name (domain));
 
-  if (qf != nullptr)
-    retval = qf->lookup_symbol (this, kind, name, domain);
+  for (const auto &iter : qf)
+    {
+      retval = iter->lookup_symbol (this, kind, name, domain);
+      if (retval != nullptr)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog, "qf->lookup_symbol (...) = %s\n",
@@ -180,8 +196,8 @@ objfile::print_stats (bool print_bcache)
     fprintf_filtered (gdb_stdlog, "qf->print_stats (%s, %d)\n",
 		      objfile_debug_name (this), print_bcache);
 
-  if (qf != nullptr)
-    qf->print_stats (this, print_bcache);
+  for (const auto &iter : qf)
+    iter->print_stats (this, print_bcache);
 }
 
 void
@@ -191,8 +207,8 @@ objfile::dump ()
     fprintf_filtered (gdb_stdlog, "qf->dump (%s)\n",
 		      objfile_debug_name (this));
 
-  if (qf != nullptr)
-    qf->dump (this);
+  for (const auto &iter : qf)
+    iter->dump (this);
 }
 
 void
@@ -203,8 +219,8 @@ objfile::expand_symtabs_for_function (const char *func_name)
 		      "qf->expand_symtabs_for_function (%s, \"%s\")\n",
 		      objfile_debug_name (this), func_name);
 
-  if (qf != nullptr)
-    qf->expand_symtabs_for_function (this, func_name);
+  for (const auto &iter : qf)
+    iter->expand_symtabs_for_function (this, func_name);
 }
 
 void
@@ -214,8 +230,8 @@ objfile::expand_all_symtabs ()
     fprintf_filtered (gdb_stdlog, "qf->expand_all_symtabs (%s)\n",
 		      objfile_debug_name (this));
 
-  if (qf != nullptr)
-    qf->expand_all_symtabs (this);
+  for (const auto &iter : qf)
+    iter->expand_all_symtabs (this);
 }
 
 void
@@ -226,8 +242,8 @@ objfile::expand_symtabs_with_fullname (const char *fullname)
 		      "qf->expand_symtabs_with_fullname (%s, \"%s\")\n",
 		      objfile_debug_name (this), fullname);
 
-  if (qf != nullptr)
-    qf->expand_symtabs_with_fullname (this, fullname);
+  for (const auto &iter : qf)
+    iter->expand_symtabs_with_fullname (this, fullname);
 }
 
 void
@@ -244,9 +260,9 @@ objfile::map_matching_symbols
 		      domain_name (domain), global,
 		      host_address_to_string (ordered_compare));
 
-  if (qf != nullptr)
-    qf->map_matching_symbols (this, name, domain, global,
-			      callback, ordered_compare);
+  for (const auto &iter : qf)
+    iter->map_matching_symbols (this, name, domain, global,
+				callback, ordered_compare);
 }
 
 void
@@ -266,9 +282,9 @@ objfile::expand_symtabs_matching
 		      host_address_to_string (&expansion_notify),
 		      search_domain_name (kind));
 
-  if (qf != nullptr)
-    qf->expand_symtabs_matching (this, file_matcher, lookup_name,
-				 symbol_matcher, expansion_notify, kind);
+  for (const auto &iter : qf)
+    iter->expand_symtabs_matching (this, file_matcher, lookup_name,
+				   symbol_matcher, expansion_notify, kind);
 }
 
 struct compunit_symtab *
@@ -288,9 +304,13 @@ objfile::find_pc_sect_compunit_symtab (struct bound_minimal_symbol msymbol,
 		      host_address_to_string (section),
 		      warn_if_readin);
 
-  if (qf != nullptr)
-    retval = qf->find_pc_sect_compunit_symtab (this, msymbol, pc, section,
-					       warn_if_readin);
+  for (const auto &iter : qf)
+    {
+      retval = iter->find_pc_sect_compunit_symtab (this, msymbol, pc, section,
+						   warn_if_readin);
+      if (retval != nullptr)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog,
@@ -314,8 +334,8 @@ objfile::map_symbol_filenames (symbol_filename_ftype *fun, void *data,
 		      host_address_to_string (data),
 		      need_fullname);
 
-  if (qf != nullptr)
-    qf->map_symbol_filenames (this, fun, data, need_fullname);
+  for (const auto &iter : qf)
+    iter->map_symbol_filenames (this, fun, data, need_fullname);
 }
 
 struct compunit_symtab *
@@ -328,8 +348,12 @@ objfile::find_compunit_symtab_by_address (CORE_ADDR address)
 		      hex_string (address));
 
   struct compunit_symtab *result = NULL;
-  if (qf != nullptr)
-    result = qf->find_compunit_symtab_by_address (this, address);
+  for (const auto &iter : qf)
+    {
+      result = iter->find_compunit_symtab_by_address (this, address);
+      if (result != nullptr)
+	break;
+    }
 
   if (debug_symfile)
     fprintf_filtered (gdb_stdlog,
@@ -347,12 +371,15 @@ objfile::lookup_global_symbol_language (const char *name,
 					bool *symbol_found_p)
 {
   enum language result = language_unknown;
+  *symbol_found_p = false;
 
-  if (qf != nullptr)
-    result = qf->lookup_global_symbol_language (this, name, domain,
-						symbol_found_p);
-  else
-    *symbol_found_p = false;
+  for (const auto &iter : qf)
+    {
+      result = iter->lookup_global_symbol_language (this, name, domain,
+						    symbol_found_p);
+      if (*symbol_found_p)
+	break;
+    }
 
   return result;
 }
@@ -364,17 +391,23 @@ objfile::require_partial_symbols (bool verbose)
     {
       flags |= OBJF_PSYMTABS_READ;
 
-      if (qf->can_lazily_read_symbols ())
+      bool printed = false;
+      for (const auto &iter : qf)
 	{
-	  if (verbose)
-	    printf_filtered (_("Reading symbols from %s...\n"),
-			     objfile_name (this));
-	  qf->read_partial_symbols (this);
-
-	  if (verbose && !objfile_has_symbols (this))
-	    printf_filtered (_("(No debugging symbols found in %s)\n"),
-			     objfile_name (this));
+	  if (iter->can_lazily_read_symbols ())
+	    {
+	      if (verbose && !printed)
+		{
+		  printf_filtered (_("Reading symbols from %s...\n"),
+				   objfile_name (this));
+		  printed = true;
+		}
+	      iter->read_partial_symbols (this);
+	    }
 	}
+      if (printed && !objfile_has_symbols (this))
+	printf_filtered (_("(No debugging symbols found in %s)\n"),
+			 objfile_name (this));
     }
 }