[RFC/RFA/i386] pb reading insns if breakpoints still inserted

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

following a discussion that started in:

        http://sources.redhat.com/ml/gdb-patches/2006-04/msg00345.html

Here is a patch that fixes the problem. In summary: When we do next/step
operations, we end up parsing the top frame function prologue and
creating a frame_info with it. Unfortunately, at that point, the
breakpoints are still inserted and that causes the prologue analyzer
to misinterpret the function prologue and consequently breaks unwinding
a bit.

The fix that has been suggested is to fix the i386 prologue analyzer
to handle inserted breakpoints. This is what the new read_insn()
function does. I've always been very bad with names, so suggestions
are more than welcome.

I also think that read_insn() might be better located in a more general
area, such as beside the various read_memory routines for instance. But
before moving this function, I thought I'd ask...

2006-04-28  Joel Brobecker  <brobecker@adacore.com>

        * i386-tdep.c (read_insn): New function.
        (i386_follow_jump): Use read_insn to read instructions.
        (i386_analyze_struct_return): Likewise.
        (i386_skip_probe): Likewise.
        (i386_match_insn): Likewise.
        (i386_analyze_frame_setup): Likewise.
        (i386_analyze_register_saves): Likewise.
        (i386_skip_prologue): Likewise.

Tested on i686-pc-cygwin. No regression. Testcase to follow shortly.
OK to apply? 

Thanks,
-- 
Joel

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