RE: [PATCH 1/1] gdb, gdbserver: replace PBUFSIZ with a target op

["Gerlicher, Klaus" <klaus.gerlicher@intel.com>]

Hi Simon,

Thanks for the quick response.

At least the initial buffer size needs to be fixed since now most clients aren't aware of any dynamic behavior here and therefore we need at least something pre-allocated for these clients.

For the clients interested we could change the CS buffer to a re-allocatable type that is pre-allocated with the current PBUFSIZ. We could pass this buffer around with a target op. The target could resize at will instead of letting it return a fixed number.

Is this something in line that you would support?

Klaus

-----Original Message-----
From: Simon Marchi <simon.marchi@polymtl.ca> 
Sent: Tuesday, September 19, 2023 4:08 PM
To: Gerlicher, Klaus <klaus.gerlicher@intel.com>; gdb-patches@sourceware.org
Subject: Re: [PATCH 1/1] gdb, gdbserver: replace PBUFSIZ with a target op

On 9/19/23 01:45, Klaus Gerlicher via Gdb-patches wrote:
> From: "Gerlicher, Klaus" <klaus.gerlicher@intel.com>
> 
> PBUFSIZ is a hardcoded value that needs to be as least twice as big as 
> the register set.
> 
> This means that this could be tailored to the target register size as 
> not all targets need a big buffer. For SIMD targets the buffer will 
> obviously be much bigger than for regular scalar targets.
> 
> This patch changes this and adds a target op query_pbuf_size (). It 
> also moves the static global client_state into the get_client_state () 
> function and lazily dynamically allocates storage for its own_buf.

Just throwing an idea out there... instead of trying to determine a buffer size that is large enough, can we instead pass something like an std::vector (gdb::char_vector or gdb::byte_vector) around, and whatever builds the packets and replies makes sure there is enough space?

Simon
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