[RFC PATCH 0/1] gdb/riscv: Cache per-BFD disassembler

[Tsukasa OI <research_trasio@irq.a4lg.com>]

Hello,

On RISC-V, calling the disassembler function (libopcodes) is not a small
cost.  This is because riscv_get_disassembler function sets the default
architecture from given BFD's .riscv.attributes section.  However, by
default, GDB calls this function for every instruction.

This commit replaces RISC-V's disassembler function and stop calling
riscv_get_disassembler function if current BFD has not changed.

It expects around 30-80% improvements on disassembling relatively large
chunk of RISC-V code but most of them will be obscured by a RISC-V
disassembler optimization the author is currently working on.  Still, 3-5%
of performance improvements will remain (due to reduced BFD section reads).

[REQUEST FOR COMMENTS]

I'm confident that most of BFD contents won't change so dynamically on GDB
and caching itself is not a bad idea.  Still, I'm not sure whether this
usage of "static" variables is okay.

I would like to hear your thoughts.

Thanks,
Tsukasa




Tsukasa OI (1):
  gdb/riscv: Cache per-BFD disassembler

 gdb/riscv-tdep.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)


base-commit: c10a862f17847bc9c50d680c87b87dc51ae4b95e
-- 
2.34.1