Add a comment describing the difference between readelf and objdump.

3 files changed, 31 insertions, 1 deletions

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 3b73d06..e7d5309 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,10 @@
+2003-11-26  Daniel Jacobowitz <drow@mvista.com>
+            Nick Clifton  <nickc@redhat.com>
+
+	* readelf.c: Add a comment describing the difference between
+	readelf and objdump.
+        * doc/binutils.texi (readelf): Likewise.
+
 2003-11-25  Danny Smith  <dannysmith@users.sourceforge.net>
 
 	* doc/binutils.texi (dlltool): Document dlltool --temp-prefix
diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
index 128645c..ffa680f 100644
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@@ -3129,6 +3129,11 @@ files.  The options control what particular information to display.
 @var{elffile}@dots{} are the object files to be examined.  32-bit and
 64-bit ELF files are supported, as are archives containing ELF files.
 
+This program performs a similar function to @command{objdump} but it
+goes into more detail and it exists independently of the @sc{bfd}
+library, so if there is a bug in @sc{bfd} then readelf will not be
+affected.
+
 @c man end
 
 @c man begin OPTIONS readelf
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 9b8b12e..a11d53b 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -21,7 +21,25 @@
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
    02111-1307, USA.  */
 
-
+/* The difference between readelf and objdump:
+
+  Both programs are capabale of displaying the contents of ELF format files,
+  so why does the binutils project have two file dumpers ?
+  
+  The reason is that objdump sees an ELF file through a BFD filter of the
+  world; if BFD has a bug where, say, it disagrees about a machine constant
+  in e_flags, then the odds are good that it will remain internally
+  consistent.  The linker sees it the BFD way, objdump sees it the BFD way,
+  GAS sees it the BFD way.  There was need for a tool to go find out what
+  the file actually says.
+
+  This is why the readelf program does not link against the BFD library - it
+  exists as an independent program to help verify the correct working of BFD.
+
+  There is also the case that readelf can provide more information about an
+  ELF file than is provided by objdump.  In particular it can display DWARF
+  debugging information which (at the moment) objdump cannot.  */
+
 #include <assert.h>
 #include <sys/types.h>
 #include <sys/stat.h>