DWARF info on i386-ELF Linux -- need pointers
Ian Lance Taylor
ian@zembu.com
Thu Jul 1 00:00:00 GMT 1999
From: "Ben Combee" <bcombee@metrowerks.com>
Date: Tue, 22 Jun 1999 17:54:56 -0500
I'm trying to produce DWARF debugging information suitable for use with gdb
and the binutils on i386 ELF-based Linux. I've read the DWARF 1.1
specification and looked at the source code for BFD, but I cannot figure out
the right mapping of x86 registers to DWARF register numbers. Can anyone
here provide me a pointer as to where to look? I'm especially interested in
the floating point/MMX registers, as EAX-EBP have fairly obvious encodings
based on the opcode format.
There are two natural places to look: gcc and gdb. gcc has to
generate the register mappings, and gdb has to interpret them. The
binutils don't care.
In gcc, see DBX_REGISTER_NUMBER in gcc/config/i386/sysv4.h.
In gdb, I think the right place is gdb/config/i386/tm-i386.h.
However, I believe that in neither place will you find any register
number assignments for the MMX registers. I don't think gcc ever
generates code that uses the MMX registers, so it does not need to
define any debugging information for them.
Ian
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