gdb/doc: be more verbose about .gdb_index changes in version 9

I had reason to read the docs relating to .gdb_index format, and ended
up having to look at historical versions of the documentation in order
to clarify exactly what changed with the introduction of version 9.

Given that we claim versions 7, 8, and 9 are all still allowable index
versions, I think our docs should make it clear what the current
format is, but also what previous formats looked like.

I did try to do the same for the changes from 7 to 8, but even after
reading commit 796a7ff8234cfaa8a I'm still not entirely clear what
changed.  If I gain some insight in the future then there might be a
follow on patch for that too.

Approved-By: Eli Zaretskii <eliz@gnu.org>

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index e851588382065e577b648716ff4ab74efcb5920e..a13d5c0388ecb2a1ab7b4988e50b63bd6ffa6227 100644 (file)
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -50809,7 +50809,8 @@ The offset, from the start of the file, of the address area.
 The offset, from the start of the file, of the symbol table.
 
 @item
-The offset, from the start of the file, of the shortcut table.
+The offset, from the start of the file, of the shortcut table.  This
+field was introduced with index version 9.
 
 @item
 The offset, from the start of the file, of the constant pool.
@@ -50902,6 +50903,8 @@ in the constant pool.  This value must be ignored if the value for the language
 of main is zero.
 @end table
 
+This data structure was introduced in index version 9.
+
 @item
 The constant pool.  This is simply a bunch of bytes.  It is organized
 so that alignment is correct: CU vectors are stored first, followed by