1 files changed, 161 insertions, 32 deletions

diff --git a/gdb/dwarf2/dwz.c b/gdb/dwarf2/dwz.c
index e5e18a1..583103b 100644
--- a/gdb/dwarf2/dwz.c
+++ b/gdb/dwarf2/dwz.c
@@ -21,6 +21,7 @@
 
 #include "build-id.h"
 #include "debuginfod-support.h"
+#include "dwarf2/leb.h"
 #include "dwarf2/read.h"
 #include "dwarf2/sect-names.h"
 #include "filenames.h"
@@ -34,15 +35,17 @@
 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 "
+    error (_("supplementary DWARF file missing .debug_str "
 	     "section [in module %s]"),
 	   this->filename ());
   if (str_offset >= str.size)
-    error (_("DW_FORM_GNU_strp_alt pointing outside of "
-	     ".debug_str section [in module %s]"),
+    error (_("invalid string reference to supplementary DWARF file "
+	     "[in module %s]"),
 	   this->filename ());
   gdb_assert (HOST_CHAR_BIT == 8);
   if (str.buffer[str_offset] == '\0')
@@ -85,6 +88,139 @@ locate_dwz_sections (struct objfile *objfile, bfd *abfd, asection *sectp,
     }
 }
 
+/* Helper that throws an exception when reading the .debug_sup
+   section.  */
+
+static void
+debug_sup_failure (const char *text, bfd *abfd)
+{
+  error (_("%s [in modules %s]"), text, bfd_get_filename (abfd));
+}
+
+/* Look for the .debug_sup section and read it.  If the section does
+   not exist, this returns false.  If the section does exist but fails
+   to parse for some reason, an exception is thrown.  Otherwise, if
+   everything goes well, this returns true and fills in the out
+   parameters.  */
+
+static bool
+get_debug_sup_info (bfd *abfd,
+		    std::string *filename,
+		    size_t *buildid_len,
+		    gdb::unique_xmalloc_ptr<bfd_byte> *buildid)
+{
+  asection *sect = bfd_get_section_by_name (abfd, ".debug_sup");
+  if (sect == nullptr)
+    return false;
+
+  bfd_byte *contents;
+  if (!bfd_malloc_and_get_section (abfd, sect, &contents))
+    debug_sup_failure (_("could not read .debug_sup section"), abfd);
+
+  gdb::unique_xmalloc_ptr<bfd_byte> content_holder (contents);
+  bfd_size_type size = bfd_section_size (sect);
+
+  /* Version of this section.  */
+  if (size < 4)
+    debug_sup_failure (_(".debug_sup section too short"), abfd);
+  unsigned int version = read_2_bytes (abfd, contents);
+  contents += 2;
+  size -= 2;
+  if (version != 5)
+    debug_sup_failure (_(".debug_sup has wrong version number"), abfd);
+
+  /* Skip the is_supplementary value.  We already ensured there were
+     enough bytes, above.  */
+  ++contents;
+  --size;
+
+  /* The spec says that in the supplementary file, this must be \0,
+     but it doesn't seem very important.  */
+  const char *fname = (const char *) contents;
+  size_t len = strlen (fname) + 1;
+  if (filename != nullptr)
+    *filename = fname;
+  contents += len;
+  size -= len;
+
+  if (size == 0)
+    debug_sup_failure (_(".debug_sup section missing ID"), abfd);
+
+  unsigned int bytes_read;
+  *buildid_len = read_unsigned_leb128 (abfd, contents, &bytes_read);
+  contents += bytes_read;
+  size -= bytes_read;
+
+  if (size < *buildid_len)
+    debug_sup_failure (_("extra data after .debug_sup section ID"), abfd);
+
+  if (*buildid_len != 0)
+    buildid->reset ((bfd_byte *) xmemdup (contents, *buildid_len,
+					  *buildid_len));
+
+  return true;
+}
+
+/* Validate that ABFD matches the given BUILDID.  If DWARF5 is true,
+   then this is done by examining the .debug_sup data.  */
+
+static bool
+verify_id (bfd *abfd, size_t len, const bfd_byte *buildid, bool dwarf5)
+{
+  if (!bfd_check_format (abfd, bfd_object))
+    return false;
+
+  if (dwarf5)
+    {
+      size_t new_len;
+      gdb::unique_xmalloc_ptr<bfd_byte> new_id;
+
+      if (!get_debug_sup_info (abfd, nullptr, &new_len, &new_id))
+	return false;
+      return (len == new_len
+	      && memcmp (buildid, new_id.get (), len) == 0);
+    }
+  else
+    return build_id_verify (abfd, len, buildid);
+}
+
+/* Find either the .debug_sup or .gnu_debugaltlink section and return
+   its contents.  Returns true on success and sets out parameters, or
+   false if nothing is found.  */
+
+static bool
+read_alt_info (bfd *abfd, std::string *filename,
+	       size_t *buildid_len,
+	       gdb::unique_xmalloc_ptr<bfd_byte> *buildid,
+	       bool *dwarf5)
+{
+  if (get_debug_sup_info (abfd, filename, buildid_len, buildid))
+    {
+      *dwarf5 = true;
+      return true;
+    }
+
+  bfd_size_type buildid_len_arg;
+  bfd_set_error (bfd_error_no_error);
+  bfd_byte *buildid_out;
+  gdb::unique_xmalloc_ptr<char> new_filename
+    (bfd_get_alt_debug_link_info (abfd, &buildid_len_arg,
+				  &buildid_out));
+  if (new_filename == nullptr)
+    {
+      if (bfd_get_error () == bfd_error_no_error)
+	return false;
+      error (_("could not read '.gnu_debugaltlink' section: %s"),
+	     bfd_errmsg (bfd_get_error ()));
+    }
+  *filename = new_filename.get ();
+
+  *buildid_len = buildid_len_arg;
+  buildid->reset (buildid_out);
+  *dwarf5 = false;
+  return true;
+}
+
 /* Attempt to find a .dwz file (whose full path is represented by
    FILENAME) in all of the specified debug file directories provided.
 
@@ -93,7 +229,7 @@ locate_dwz_sections (struct objfile *objfile, bfd *abfd, asection *sectp,
 
 static gdb_bfd_ref_ptr
 dwz_search_other_debugdirs (std::string &filename, bfd_byte *buildid,
-			    size_t buildid_len)
+			    size_t buildid_len, bool dwarf5)
 {
   /* Let's assume that the path represented by FILENAME has the
      "/.dwz/" subpath in it.  This is what (most) GNU/Linux
@@ -161,7 +297,7 @@ dwz_search_other_debugdirs (std::string &filename, bfd_byte *buildid,
       if (dwz_bfd == nullptr)
 	continue;
 
-      if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
+      if (!verify_id (dwz_bfd.get (), buildid_len, buildid, dwarf5))
 	{
 	  dwz_bfd.reset (nullptr);
 	  continue;
@@ -177,11 +313,8 @@ 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;
-  bfd_byte *buildid;
   dwarf2_per_bfd *per_bfd = per_objfile->per_bfd;
 
   /* This may query the user via the debuginfod support, so it may
@@ -193,24 +326,17 @@ dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
   /* Set this early, so that on error it remains NULL.  */
   per_bfd->dwz_file.emplace (nullptr);
 
-  bfd_set_error (bfd_error_no_error);
-  gdb::unique_xmalloc_ptr<char> data
-    (bfd_get_alt_debug_link_info (per_bfd->obfd,
-				  &buildid_len_arg, &buildid));
-  if (data == NULL)
+  size_t buildid_len;
+  gdb::unique_xmalloc_ptr<bfd_byte> buildid;
+  std::string filename;
+  bool dwarf5;
+  if (!read_alt_info (per_bfd->obfd, &filename, &buildid_len, &buildid,
+		      &dwarf5))
     {
-      if (bfd_get_error () == bfd_error_no_error)
-	return;
-      error (_("could not read '.gnu_debugaltlink' section: %s"),
-	     bfd_errmsg (bfd_get_error ()));
+      /* Nothing found, nothing to do.  */
+      return;
     }
 
-  gdb::unique_xmalloc_ptr<bfd_byte> buildid_holder (buildid);
-
-  buildid_len = (size_t) buildid_len_arg;
-
-  std::string filename = data.get ();
-
   if (!IS_ABSOLUTE_PATH (filename.c_str ()))
     {
       gdb::unique_xmalloc_ptr<char> abs = gdb_realpath (per_bfd->filename ());
@@ -223,25 +349,26 @@ dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
   gdb_bfd_ref_ptr dwz_bfd (gdb_bfd_open (filename.c_str (), gnutarget));
   if (dwz_bfd != NULL)
     {
-      if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
+      if (!verify_id (dwz_bfd.get (), buildid_len, buildid.get (), dwarf5))
 	dwz_bfd.reset (nullptr);
     }
 
   if (dwz_bfd == NULL)
-    dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid);
+    dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid.get ());
 
   if (dwz_bfd == nullptr)
     {
       /* If the user has provided us with different
 	 debug file directories, we can try them in order.  */
-      dwz_bfd = dwz_search_other_debugdirs (filename, buildid, buildid_len);
+      dwz_bfd = dwz_search_other_debugdirs (filename, buildid.get (),
+					    buildid_len, dwarf5);
     }
 
   if (dwz_bfd == nullptr)
     {
       gdb::unique_xmalloc_ptr<char> alt_filename;
       scoped_fd fd
-	= debuginfod_debuginfo_query (buildid, buildid_len,
+	= debuginfod_debuginfo_query (buildid.get (), buildid_len,
 				      per_bfd->filename (), &alt_filename);
 
       if (fd.get () >= 0)
@@ -252,16 +379,18 @@ dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
 	  if (dwz_bfd == nullptr)
 	    warning (_("File \"%s\" from debuginfod cannot be opened as bfd"),
 		     alt_filename.get ());
-	  else if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
+	  else if (!verify_id (dwz_bfd.get (), buildid_len, buildid.get (),
+			       dwarf5))
 	    dwz_bfd.reset (nullptr);
 	}
     }
 
   if (dwz_bfd == NULL)
-    error (_("could not find '.gnu_debugaltlink' file for %s"),
+    error (_("could not find supplementary DWARF file (%s) for %s"),
+	   filename.c_str (),
 	   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 (),