Unify read_initial_length implementations

There are two implementations of read_initial_length in gdb.  This
merges them and moves the resulting function to leb.c.

2020-02-08  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.c (read_initial_length): Move to leb.c.
	* dwarf2/leb.h (read_initial_length): Declare.
	* dwarf2/leb.c (read_initial_length): Move from read.c.  Add
	handle_nonstd parameter.
	* dwarf2/frame.c (read_initial_length): Remove.
	(decode_frame_entry_1): Update.

Change-Id: I34d37bad0f8a584bfa781432cba25e05e1bd5750

1 files changed, 27 insertions, 0 deletions

diff --git a/gdb/dwarf2/leb.c b/gdb/dwarf2/leb.c
index d26b48b..ef7314e 100644
--- a/gdb/dwarf2/leb.c
+++ b/gdb/dwarf2/leb.c
@@ -83,3 +83,30 @@ read_signed_leb128 (bfd *abfd, const gdb_byte *buf,
   *bytes_read_ptr = num_read;
   return result;
 }
+
+/* See leb.h.  */
+
+LONGEST
+read_initial_length (bfd *abfd, const gdb_byte *buf, unsigned int *bytes_read,
+		     bool handle_nonstd)
+{
+  LONGEST length = bfd_get_32 (abfd, buf);
+
+  if (length == 0xffffffff)
+    {
+      length = bfd_get_64 (abfd, buf + 4);
+      *bytes_read = 12;
+    }
+  else if (handle_nonstd && length == 0)
+    {
+      /* Handle the (non-standard) 64-bit DWARF2 format used by IRIX.  */
+      length = bfd_get_64 (abfd, buf);
+      *bytes_read = 8;
+    }
+  else
+    {
+      *bytes_read = 4;
+    }
+
+  return length;
+}