Determine the factors contributing to unexpected slowdowns during self-hosting

[jserv]

This project has the capability for self-hosting, transitioning from native compilation in stage 1 to stage 2. Given that shecc is composed in ANSI C, it allows for the use of any compiler across various platforms for the initial compilation. This process is further facilitated through the use of RISC-V and/or Arm emulators for bootstrapping. Nevertheless, we are experiencing unforeseen delays during the self-hosting process, particularly in the execution times of stages 1 and 2. Our aim is to conduct a thorough investigation into the causes of these slowdowns.

We can use uftrace to identify the sources of slowdowns.

[vacantron]

After #90 , it no more needs to run the qemu on the ARM32 host. The time of the stage-2 build has decreased from ~25s to 4s.

The uftrace needs the debug symbols (built with GCC "-g" and "-finstrument-functions" flags) to trace the executable file. We can only use it in the stage-1 build, instead, we can use perf to identify the slowdowns in the stage-2 build.

[vacantron]

@jserv , should we close and migrate this topic into #88 ?