[09/15] Simplify the public DWARF API

diff --git a/gdb/coffread.c b/gdb/coffread.c
index 4a6a83b15ad..b0c9c47f13d 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -718,11 +718,9 @@  coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 			       *info->stabsects,
 			       info->stabstrsect->filepos, stabstrsize);
     }
-  if (dwarf2_has_info (objfile, NULL))
-    {
-      /* DWARF2 sections.  */
-      dwarf2_initialize_objfile (objfile);
-    }
+
+  /* DWARF2 sections.  */
+  dwarf2_initialize_objfile (objfile);
 
   /* Try to add separate debug file if no symbols table found.   */
   if (!objfile->has_partial_symbols ())
diff --git a/gdb/dwarf2/public.h b/gdb/dwarf2/public.h
index 0e74857eb1a..efb754b5fe8 100644
--- a/gdb/dwarf2/public.h
+++ b/gdb/dwarf2/public.h
@@ -20,10 +20,6 @@ 
 #ifndef DWARF2_PUBLIC_H
 #define DWARF2_PUBLIC_H
 
-extern bool dwarf2_has_info (struct objfile *,
-			     const struct dwarf2_debug_sections *,
-			     bool = false);
-
 /* A DWARF names index variant.  */
 enum class dw_index_kind
 {
@@ -34,9 +30,17 @@  enum class dw_index_kind
   DEBUG_NAMES,
 };
 
-/* Initialize for reading DWARF for OBJFILE, and push the appropriate
-   entry on the objfile's "qf" list.  */
-extern void dwarf2_initialize_objfile (struct objfile *objfile);
+/* Try to locate the sections we need for DWARF 2 debugging
+   information.  If these are found, begin reading the DWARF and
+   return true.  Otherwise, return false.  NAMES points to the dwarf2
+   section names, or is NULL if the standard ELF names are used.
+   CAN_COPY is true for formats where symbol interposition is possible
+   and so symbol values must follow copy relocation rules.  */
+
+extern bool dwarf2_initialize_objfile
+     (struct objfile *,
+      const struct dwarf2_debug_sections * = nullptr,
+      bool = false);
 
 extern void dwarf2_build_frame_info (struct objfile *);
 
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 3dbe65432d2..5a32710233d 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -1357,14 +1357,10 @@  dwarf2_per_objfile::set_symtab (const dwarf2_per_cu_data *per_cu,
   this->m_symtabs[per_cu->index] = symtab;
 }
 
-/* Try to locate the sections we need for DWARF 2 debugging
-   information and return true if we have enough to do something.
-   NAMES points to the dwarf2 section names, or is NULL if the standard
-   ELF names are used.  CAN_COPY is true for formats where symbol
-   interposition is possible and so symbol values must follow copy
-   relocation rules.  */
+/* Helper function for dwarf2_initialize_objfile that creates the
+   per-BFD object.  */
 
-bool
+static bool
 dwarf2_has_info (struct objfile *objfile,
 		 const struct dwarf2_debug_sections *names,
 		 bool can_copy)
@@ -3211,9 +3207,14 @@  static quick_symbol_functions_up make_cooked_index_funcs
 
 /* See dwarf2/public.h.  */
 
-void
-dwarf2_initialize_objfile (struct objfile *objfile)
+bool
+dwarf2_initialize_objfile (struct objfile *objfile,
+			   const struct dwarf2_debug_sections *names,
+			   bool can_copy)
 {
+  if (!dwarf2_has_info (objfile, names, can_copy))
+    return false;
+
   dwarf2_per_objfile *per_objfile = get_dwarf2_per_objfile (objfile);
   dwarf2_per_bfd *per_bfd = per_objfile->per_bfd;
 
@@ -3245,48 +3246,42 @@  dwarf2_initialize_objfile (struct objfile *objfile)
 	= create_quick_file_names_table (per_bfd->all_units.size ());
 
       objfile->qf.emplace_front (new readnow_functions);
-      return;
     }
-
   /* Was a GDB index already read when we processed an objfile sharing
      PER_BFD?  */
-  if (per_bfd->index_table != nullptr)
+  else if (per_bfd->index_table != nullptr)
     {
       dwarf_read_debug_printf ("re-using symbols");
       objfile->qf.push_front (per_bfd->index_table->make_quick_functions ());
-      return;
     }
-
-  if (dwarf2_read_debug_names (per_objfile))
+  else if (dwarf2_read_debug_names (per_objfile))
     {
       dwarf_read_debug_printf ("found debug names");
       objfile->qf.push_front
 	(per_bfd->index_table->make_quick_functions ());
-      return;
     }
-
-  if (dwarf2_read_gdb_index (per_objfile,
-			     get_gdb_index_contents_from_section<struct dwarf2_per_bfd>,
-			     get_gdb_index_contents_from_section<dwz_file>))
+  else if (dwarf2_read_gdb_index (per_objfile,
+				  get_gdb_index_contents_from_section<struct dwarf2_per_bfd>,
+				  get_gdb_index_contents_from_section<dwz_file>))
     {
       dwarf_read_debug_printf ("found gdb index from file");
       objfile->qf.push_front (per_bfd->index_table->make_quick_functions ());
-      return;
     }
-
   /* ... otherwise, try to find the index in the index cache.  */
-  if (dwarf2_read_gdb_index (per_objfile,
+  else if (dwarf2_read_gdb_index (per_objfile,
 			     get_gdb_index_contents_from_cache,
 			     get_gdb_index_contents_from_cache_dwz))
     {
       dwarf_read_debug_printf ("found gdb index from cache");
       global_index_cache.hit ();
       objfile->qf.push_front (per_bfd->index_table->make_quick_functions ());
-      return;
     }
-
-  global_index_cache.miss ();
-  objfile->qf.push_front (make_cooked_index_funcs (per_objfile));
+  else
+    {
+      global_index_cache.miss ();
+      objfile->qf.push_front (make_cooked_index_funcs (per_objfile));
+    }
+  return true;
 }
 
 
diff --git a/gdb/elfread.c b/gdb/elfread.c
index 7900dfbc388..d12dbc25f7a 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -1200,8 +1200,10 @@  elf_symfile_read_dwarf2 (struct objfile *objfile,
 {
   bool has_dwarf2 = true;
 
-  if (dwarf2_has_info (objfile, NULL, true))
-    dwarf2_initialize_objfile (objfile);
+  if (dwarf2_initialize_objfile (objfile, nullptr, true))
+    {
+      /* Nothing.  */
+    }
   /* If the file has its own symbol tables it has no separate debug
      info.  `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
      SYMTABS/PSYMTABS.	`.gnu_debuglink' may no longer be present with
diff --git a/gdb/machoread.c b/gdb/machoread.c
index 38c252c2861..e701a7366c2 100644
--- a/gdb/machoread.c
+++ b/gdb/machoread.c
@@ -785,6 +785,8 @@  macho_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
      macho_symfile_read_all_oso at the end of this function.  */
   gdb::def_vector<asymbol *> symbol_table;
 
+  dwarf2_initialize_objfile (objfile);
+
   /* Get symbols from the symbol table only if the file is an executable.
      The symbol table of object files is not relocated and is expected to
      be in the executable.  */
@@ -822,9 +824,6 @@  macho_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 	}
 
       /* Try to read .eh_frame / .debug_frame.  */
-      /* First, locate these sections.  We ignore the result status
-	 as it only checks for debug info.  */
-      dwarf2_has_info (objfile, NULL);
       dwarf2_build_frame_info (objfile);
 
       /* Check for DSYM file.  */
@@ -854,12 +853,6 @@  macho_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 	}
     }
 
-  if (dwarf2_has_info (objfile, NULL))
-    {
-      /* DWARF 2 sections */
-      dwarf2_initialize_objfile (objfile);
-    }
-
   /* Then the oso.  */
   if (!oso_vector.empty ())
     macho_symfile_read_all_oso (&oso_vector, objfile, symfile_flags);
diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
index e6ecf2a6de5..23fd38c9aa2 100644
--- a/gdb/xcoffread.c
+++ b/gdb/xcoffread.c
@@ -2871,8 +2871,7 @@  xcoff_initial_scan (struct objfile *objfile, symfile_add_flags symfile_flags)
 
   /* DWARF2 sections.  */
 
-  if (dwarf2_has_info (objfile, &dwarf2_xcoff_names))
-    dwarf2_initialize_objfile (objfile);
+  dwarf2_initialize_objfile (objfile, &dwarf2_xcoff_names);
 }
 
 static void