Tracing allocations with "new" in dmd

[Tim]

On Friday, 19 June 2020 at 13:45:23 UTC, Andrei Alexandrescu 
wrote:
> dmd does most of its allcoation with new. I wonder what would 
> be the easiest way to track how many instances of each type are 
> created.
>
> There are over 3000 call sites, so ideally the changes to the 
> source would be entirely automatic (e.g. with sed).
>
> Would be in your debt for any ideas. Thanks!

You can also use heaptrack for tracing allocations under Linux. 
It uses LD_PRELOAD to replace allocation functions with wrappers.

I have modified heaptrack to also track allocations on the D GC 
heap: https://github.com/tim-dlang/heaptrack/tree/heaptrack-d

When using it, the application has to be linked with druntime 
dynamically. It also only works, when the application is launched 
by heaptrack, and not, when heaptrack is attached later. The 
modified heaptrack will only work with D applications.

dmd can be linked dynamically with phobos/druntime by passing 
DFLAGS="-defaultlib=phobos2 -debuglib=phobos2" to build.d.

For dmd you can call it like this:
heaptrack dmd -lowmem test.d

It will then generate a file like heaptrack.dmd.*.zst, which can 
be analyzed with heaptrack --analyze.