[tcf-dev] PPC64 v2 breakpoint support.

[Xavier Pouyollon <xavier.pouyollon@xxxxxxxxxxxxx>]

Hi Eugene,

We continue the support of PPC64 v2
In PPC64 v2, a function has
- an @, which is the global @
- a local entry point which is an offset retrieved from st_other 
associated to the symbol.

When we put a breakpoint on a symbol, we want to put the breakpoint at 
local_entry, not the global @.
(because compiler can jump directly to the local entry point if called 
from the same module).

Let's say print
0x400
Local entry offset : 8

If we issue a Breakpoints add "Location":"print", we want the breakpoint 
to be put at 0x400 + Local entry offset aka 0x408
However, if we issue Breakpoints add "Location":"print+0x20" we want the 
breakpoint to be put at 0x420.
However, if we issue Breakpoint add "Location":"0x440", we want the 
breakpoint to be put at 0x440.

So far, I have changed symbols to return a new property 
"LocalEntryOffset" returned only for PPC64. So far, so good.

My question: What's the best way to detect that we have a "pure symbol" 
(understand "Location":"print") so I can retrieve the LocalEntryOffset ?
So far, the idea is to edit plant_at_address_expression.
From Value, we can retrieve the symbol and compare the name with 
bp->location. If identical, we can retrieve the LocalOffset (through 
get_symbol_props, I love this routine) and add it to computed address 
given by value_to_address.

Does that seem a good approach to you ?

Thanks !
Xavier.