[PATCH 1/3] Remove 'read' call from dwz_file::read_string

[Tom Tromey <tom@tromey.com>]

dwz_file::read_string calls 'read' on the section, but this isn't
needed as the sections have all been pre-read.

This patch makes this change, and refactors dwz_file a bit to make
this more obvious -- by making it clear that only the "static
constructor" can create a dwz_file.
---
 gdb/dwarf2/dwz.c  |  8 +++++---
 gdb/dwarf2/dwz.h  | 25 +++++++++++++------------
 gdb/dwarf2/read.c |  2 +-
 3 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/gdb/dwarf2/dwz.c b/gdb/dwarf2/dwz.c
index f36d6a6418a4220d7d531e3bf5b6e047b40edd6e..14cd8e882ba6bc16b57a82aa31296f4025261f15 100644
--- a/gdb/dwarf2/dwz.c
+++ b/gdb/dwarf2/dwz.c
@@ -34,7 +34,9 @@
 const char *
 dwz_file::read_string (struct objfile *objfile, LONGEST str_offset)
 {
-  str.read (objfile);
+  /* This must be true because the sections are read in when the
+     dwz_file is created.  */
+  gdb_assert (str.readin);
 
   if (str.buffer == NULL)
     error (_("DW_FORM_GNU_strp_alt used without .debug_str "
@@ -177,7 +179,7 @@ dwz_search_other_debugdirs (std::string &filename, bfd_byte *buildid,
 /* See dwz.h.  */
 
 void
-dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
+dwz_file::read_dwz_file (dwarf2_per_objfile *per_objfile)
 {
   bfd_size_type buildid_len_arg;
   size_t buildid_len;
@@ -261,7 +263,7 @@ dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
     error (_("could not find '.gnu_debugaltlink' file for %s"),
 	   per_bfd->filename ());
 
-  auto result = std::make_unique<dwz_file> (std::move (dwz_bfd));
+  dwz_file_up result (new dwz_file (std::move (dwz_bfd)));
 
   for (asection *sec : gdb_bfd_sections (result->dwz_bfd))
     locate_dwz_sections (per_objfile->objfile, result->dwz_bfd.get (),
diff --git a/gdb/dwarf2/dwz.h b/gdb/dwarf2/dwz.h
index cd5143ff0848564e1c831f4eb7ddccd7231d28e6..639eea3a41850249a44259e454daa770b246ef2b 100644
--- a/gdb/dwarf2/dwz.h
+++ b/gdb/dwarf2/dwz.h
@@ -31,10 +31,12 @@ struct dwarf2_per_objfile;
 
 struct dwz_file
 {
-  dwz_file (gdb_bfd_ref_ptr &&bfd)
-    : dwz_bfd (std::move (bfd))
-  {
-  }
+  /* Open the separate '.dwz' debug file, if needed.  This will set
+     the appropriate field in the per-BFD structure.  If the DWZ file
+     exists, the relevant sections are read in as well.  Throws an
+     error if the .gnu_debugaltlink section exists but the file cannot
+     be found.  */
+  static void read_dwz_file (dwarf2_per_objfile *per_objfile);
 
   const char *filename () const
   {
@@ -64,16 +66,15 @@ struct dwz_file
      return a pointer to the string.  */
 
   const char *read_string (struct objfile *objfile, LONGEST str_offset);
-};
 
-using dwz_file_up = std::unique_ptr<dwz_file>;
+private:
 
-/* Open the separate '.dwz' debug file, if needed.  This just sets the
-   appropriate field in the per-BFD structure.  If the DWZ file
-   exists, the relevant sections are read in as well.  Throws an error
-   if the .gnu_debugaltlink section exists but the file cannot be
-   found.  */
+  explicit dwz_file (gdb_bfd_ref_ptr &&bfd)
+    : dwz_bfd (std::move (bfd))
+  {
+  }
+};
 
-extern void dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile);
+using dwz_file_up = std::unique_ptr<dwz_file>;
 
 #endif /* GDB_DWARF2_DWZ_H */
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 8875e97a7b3303c5c8bf7ca90ed21f22f4d23b34..f4198d71ca28811bd02c5fb87b5206629f118874 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -1289,7 +1289,7 @@ dwarf2_has_info (struct objfile *objfile,
 	 BFD, to avoid races.  */
       try
 	{
-	  dwarf2_read_dwz_file (per_objfile);
+	  dwz_file::read_dwz_file (per_objfile);
 	}
       catch (const gdb_exception_error &err)
 	{

-- 
2.46.1