Re: [RFC PATCH] Read pseudo registers from frame instead of regcache

[Tom Tromey <tom@tromey.com>]

>>>>> "Simon" == Simon Marchi <simon.marchi@polymtl.ca> writes:

Simon> The problem: Reading pseudo registers from an upper stack frame does not
Simon> work.  The raw registers needed to compose the pseudo registers are
Simon> always read from the current thread's regcache, which is effectively
Simon> frame #0's registers.
[...]
Simon> The gdbarch hooks

Simon>   - pseudo_register_read
Simon>   - pseudo_register_read_value
Simon>   - pseudo_register_write

Simon> receive a regcache as a parameter, as a way to get the values of the raw
Simon> registers required to compute the pseudo register value.  However, the
Simon> regcache object always contains the current register values, not the
Simon> values unwound to the frame we're interested in.

I don't know this area very well, so apologies if this is really off
target; but I am wondering why not just make a regcache for the desired
frame and pass that to the gdbarch hooks?

Another thing I am curious about is how far back this bug goes.  Like,
if it were introduced in one of the last few releases, then it might be
worth bisecting to find out what happened.

Tom